Editor’s Note: This week we’re at the virtual 237th AAS Meeting. Along with a team of authors from Astrobites, we will be writing updates on selected events at the meeting and posting each day. Follow along here or at astrobites.com. The usual posting schedule for AAS Nova will resume on January 19th.

Plenary: The Role of Magnetic Fields: Galactic Science from HAWC+/SOFIA (by Ellis Avallone)

The first plenary of the last day of AAS was all about galactic magnetic fields. Dr. David Chuss from Villanova University is an expert in submillimeter polarimetry, a technique that utilizes the polarization of light in submillimeter wavelengths to obtain information about low-magnitude magnetic fields. Today’s talk focused on results from the HAWC+ instrument, a polarimeter on the plane-turned-telescope SOFIA. HAWC+ is especially adept at detecting galactic magnetic fields, which are notoriously difficult to measure and are often neglected. By measuring the polarization of light from magnetically aligned dust grains, we can accurately trace magnetic fields throughout our galaxy. 

An hourglass-shaped magnetic field in the Orion Nebula.

A central question that drove the development of HAWC+ surrounds the role of magnetic fields in star formation. Star formation is surprisingly inefficient (both within and outside our Milky Way), and dynamic support from magnetic fields in molecular clouds can prevent the collapse of gas into stars. Magnetic fields in turn are “frozen” into matter, where they trace the motions of matter while also influencing system dynamics through magnetic pressure. It was theorized that in a gas cloud with magnetically regulated star formation, the gas would be free to collapse along magnetic field lines. However, in regions where gas motions were perpendicular to the magnetic field, magnetic pressure would prevent the gas from fully collapsing. This interaction between the magnetic pressure and gas dynamics would cause the magnetic field to follow an hourglass shape. When HAWC+ observed the Orion nebula, the closest massive star-forming region to Earth, it found the hourglass magnetic-field orientation indicative of magnetically regulated star formation. Chuss then notes that polarimetry can also be used to estimate magnetic field strengths, which can provide further insight into the balance between gas and magnetic field dynamics. With both magnetic field strength and orientation measurements, we can map the distribution of magnetic flux, which then gives us the relative importance of gravitational and magnetic motions throughout a star forming region.

Magnetic fields trace dust rings around our galactic center.

For the final portion of the talk, Chuss turned to our galactic center. Magnetic fields can also affect the dynamics of material near the centers of galaxies, and our own Milky Way provides us with an up-close example. HAWC+ looked at the region directly surrounding our central black hole, Sagittarius A*, and found magnetic field lines tracing a ring of warm dust that surrounds the region. Additionally, HAWC+ found that the magnetic fields of the cool and warm dust near the galactic center are quite different in orientation from one another. Finally, Chuss discussed the magnetic fields of radio filaments in the galactic center. These bands of electrons radiate via synchrotron emission and are bound by magnetic fields that are perpendicular to the galactic plane. HAWC+ observations suggest that reconnecting magnetic fields at the surface of cloud structures are causing electrons to be accelerated to relativistic speeds.

There are still many open questions surrounding magnetic fields in our galaxy. With HAWC+, we can begin to unravel how deeply magnetic fields permeate processes in our universe.

Special Session: Astronomy Education in a Rapidly Changing World: Best Practices from Research and Instruction (by Briley Lewis)

Cover of the recent AAS/IOP ebook edited by Drs. Chris Impey and Sanlyn Buxner, Astronomy Education, Volume 1.

As all current students and teachers know, the past year has been an off-road adventure in online teaching for many of us. Today’s special session addressed this unique challenge in education, focusing on how to support astronomy education during the pandemic. To start, Sanlyn Buxner (University of Arizona & Planetary Science Institute) introduced a great general resource: two volumes of astronomy education content recently published by AAS-IOP Astronomy. The first focused on learner-centered teaching in astronomy, and the second, more recent volume dealt with online learning specifically. 

Next, Molly Simon (Adler Planetarium) discussed using citizen science, an interactive activity well-suited for online learning. Zooniverse, which started with Galaxy Zoo, is now the largest citizen science platform with over 2 million registered volunteers worldwide and many different subjects (even beyond astronomy!). In her research, Simon realized that manipulating spreadsheets, a traditional lab activity, is not necessarily the best approach to build data literacy; instead, she has developed new materials using Zooniverse that have students draw conclusions from graphs and other data representations. These materials are accessible fully online, consisting of a lecture tutorial, citizen science activity, and guided inquiry experience. They’re doing pilot testing now, so if you want to implement it in your classroom, reach out to Molly!

Nicole Gugliucci (Saint Anselm College) brought in yet another engaging online learning activity: video games! The game “At Play in the Cosmos” by Norton ties in with their eBook and includes autograding options, and it takes students on a spaceship adventure that even guides them through relevant physics equations. Students responded positively to this, saying they liked fun ways to apply concepts like this!

Screenshot of the astronomy game used in Nicole Gugliucci’s classroom, showing the spaceship and accompanying physics.

In a presentation called “Interrupting the d00mscroll with Astronomy”, Pamela Gay (Planetary Science Institute) describes a different approach to education in the pandemic, saying that “sometimes you just have to help people get through the moment so tomorrow they can learn.” With the Cosmoquest collaboration, they have been creating content for live internet audiences. In the pandemic, she says they realized delivering content isn’t enough right now, people need a place to come together. They’ve started doing “Community Coffee” sessions on Twitch, bringing together art and science on a Monday morning to get the week started. Using Discord, they’ve built a community chat server for people to hang out. It’s moderated by a team across the world to keep a safe and inclusive space, and they’ve created open-source bots to interact with people — they even have one that will give you a reminder to stop scrolling and go to bed! They’re doing all sorts of cool things to help people get through this together and enjoy astronomy, even building a scale model of the solar system in Minecraft.

An example of the “bedtime” reminder on the Cosmoquest Discord server.

Lastly, Matthew Wenger (University of Arizona) shared about his experiences building self-paced massive open online courses (MOOCs) on Coursera. A different approach to learning than the traditional college classroom, these types of free online courses target adults seeking education out of interest. Along with collaborators, Wenger has built two different astronomy courses, and he emphasized that peer reviewed writing assignments have been key for building student engagement in this online format. Students get to interact with one another, and bonus: writing is a great way to deepen understanding and reach higher levels of Bloom’s Taxonomy of Learning like “evaluating” and “analyzing”! 

This special session gave so many great ideas for not only dealing with online learning, but helping students thrive. As one commenter said, online learning has lots of possibilities, it’s not just a lesser stand-in for face-to-face instruction!

Special Session: Supporting Marginalized Students in Astronomy: A Discussion Among Program Leaders on Best Practices and Ongoing Challenges (by Ellis Avallone)

This session, moderated by Prof. Kelle Cruz from Hunter College, invited leaders of diversity, equity, and inclusion initiatives to discuss the successes and challenges associated with these programs. Leaders of notable bridge programs and research internships were in attendance, including those from the Fisk-Vanderbilt Bridge Program, the Columbia University Bridge Program, Cal-Bridge, and AstroCom NYC. The panel discussed several topics, ranging from securing funding to implementing change in a department’s culture. The discussion started off with an introduction to bridge programs. These programs are designed to bridge the transition between undergrad and graduate school, and they typically focus on supporting and retaining marginalised students. The panelists noted that one of the challenges to running a bridge program is that, due to the length of most graduate programs, it takes a long time (on the order of 10 years) to see the results of a given bridge program and understand how it has impacted their students. A positive aspect of this is that the most successful programs provide long-term mentorship and support for their students, even after they’ve moved on to graduate school or industry. 

The session also included a discussion on how to best enact change within departments that want to tackle DEI projects but do not currently have support systems in place. A few panelists mentioned the importance of outside societies, whose primary focus is to evaluate a department and recommend concrete actions the department can take to improve their diversity (e.g. the AAS Site Visit Oversight Committee). Additionally, the AIP TEAM-UP report (covered by astrobites at AAS236) includes several recommendations on how departments can best support marginalized students. Finally, the panelists emphasized that cultural change within a department has to come from department leadership working with marginalized folks, and the panel advised students to identify allies within their departments who are focused on implementing substantial change. 

Press Conference: The Modern Milky Way (by Haley Wahl)

The first press conference of the final day of AAS 237 was all about new discoveries in our home galaxy. The first speaker was Sailee Sawant from the Florida Institute of Technology, who talked about charge-injection devices. These devices employ simple, cost-effective, yet powerful techniques that allow astronomers to image a very dim companion to a very bright star (they allow extreme contrast imaging). The team has been successful in detecting and resolving previously uncatalogued sources, along with Sirius B (the very faint companion to the star Sirius A). Press release

This image of the Integral Sign galaxy (UGC 3697) shows a galaxy with one of the largest known warps. [DECaLS]

Artist’s impression of a stellar stream arcing high in the Milky Way’s halo. [NASA]

The final talk of the session was given by Kat Barger from Texas Christian University, who talked about the Milky Way’s defense against an incoming gas cloud. She discussed Complex A, a giant gas cloud that is currently bumping elbows with our galaxy. The halo of our galaxy, however, is fighting against it and slowly dissolving the gas cloud. Complex A is currently the best-mapped gas cloud that did not originate from the Milky Way, and it helps us decipher how galaxies obtain the gas they need to form stars.

AAS Strategic Assembly Town Hall (by Haley Wahl)

This town hall, which was rescheduled from Wednesday, focused on the strategic plans of the AAS. President Paula Szkody (University of Washington) started off by introducing the AAS vision statement, which says, “We seek a world where all people value and benefit from a scientific understanding of astronomy that enhances their connection to and enjoyment of the universe around us.” She then went on to the AAS values, which state principles such as, “We act with scientific integrity and transparency as we responsibly and impartially acquire, share, manage, and use scientific data and understanding.” See image below for full set of values. 

Full list of AAS values.

After some discussion, she shared the five strategic priorities of the AAS:

1.  Build equitable and inclusive practices within the astronomy research community
2. Address significant global issues that affect astronomy
3. Improve astronomical science dissemination, scientific publication and literacy, STEM education, and professional learning across all career paths chosen by astronomers
4. Cultivate our network of partnerships to strengthen new initiatives, advance our mission, and strive toward our vision
5. Improve transparency and interconnections among the AAS Board, Divisions, Committees, and Members to accomplish our goals

The rest of the meeting was devoted to answering questions from the Slack channel (#aas-strategic-assembly-town-hall). Visit the AAS strategic planning website for more information about their strategic plans!

SOFIA Town Hall (by Abby Waggoner)

SOFIA, a modified Boeing 747SP carrying a 2.7-m telescope. [NASA]

• The first detection of molecular water on the Moon’s surface
• Results suggesting that gravitational collapse of molecular clouds and star formation can occur even in the presence of strong magnetic fields
• The detection of a “cold” quasar, a galaxy in which the central supermassive black hole is actively accreting matter, yet the star formation in the galaxy is still going strong (a surprising result, since black holes are thought to halt star formation)
• Evidence of the building blocks of complex organic molecules, found in disks around massive stars via high-resolution spectroscopy
• The first detection of the molecule ¹³CH in the interstellar medium.

Meixner highlighted that SOFIA observations were suspended March–August 2020 due to the pandemic, and the observatory is currently suspended in Hamburg, Germany for scheduled maintenance. The image below shows every flight path SOFIA took in the past year.

SOFIA flight paths for 2020.

Next up, James Jackson, the Associate Director for Research, gave us an overview of the Cycle 8 observations and Cycle 9 proposing cycle. Because of the pandemic-related shutdown, Cycle 8 is now scheduled to continue until July 2, 2021, but unfortunately the 2020 Southern Hemisphere deployment is no longer feasible. Instead, a number of flights will be conducted from Germany to accomplish high priority programs. Cycle 9 proposals vastly exceeded the available 820 hours of observing time, with 3,243.5 hours requested worldwide. The Cycle 9 breakdown is shown below. Jackson also highlighted a virtual workshop titled “Rock, Dust, and Ice: Interpreting Planetary Data” happening in March 2021.

The final section of the town hall was an overview of the current and future SOFIA instrumentation, from William Reach, the Associate Director for Science Operations. The future of SOFIA aims to address questions concerning star and planet formation, the path to life, and calibrating the distant universe. These science cases will be addressed by developing new instrument capability that will improve sensitivity, map polarization, increase mapping speed, and more. 

The presenting group concluded by highlighting that SOFIA continues to make new discoveries, and with the upcoming instrumentation upgrades, SOFIA will be able to target more and more areas of the sky and astronomy.

Plenary: Stress-testing the Cold Dark Matter Paradigm: Trouble on Small-scales? (by Luna Zagorac)

The relative amounts of the different constituents of the universe. [ESA/Planck]

This Hubble image shows part of the galaxy cluster Abell 3827. The blue structures surrounding the central galaxies are gravitationally lensed views of a much more distant galaxy behind the cluster. [ESO]

If the object doing the lensing is massive enough, we can even see multiple images of a lensed object. By mapping the objects we see multiply lensed, we can reconstruct the so-called caustics of the lensing object, which relate to its shape and concentration in its very inner parts (see Figure SL3 here for an illustration). This allows us to build a subhalo mass function: in other words, we can predict how many smaller dark matter clumps of a given mass live within a smooth dark matter distribution called a halo. This is predicted by the CDM paradigm, and the simulations agree with the data here: CDM isn’t feeling too stressed about it!

This plot shows two subhalo mass functions, with mass of subhalo in solar masses on the horizontal axis and number of subhaloes of that mass on the vertical axis. A comparison of a subhalo mass function derived from a simulation (solid black with grey uncertainty) and a subhalo mass function derived from Hubble data (red with shaded uncertainty). Note that the two lines don’t differ significantly.

What does stress CDM out is galaxy–galaxy lensing: a regime in which both the lensed and lensing objects are restricted to being galaxies. With galaxy–galaxy lensing we can probe the mass within the inner 5–10 kpc of the galaxy, gaining detailed information about mass distribution (and therefore dark matter distribution) within that range. Turns out, there is an order of magnitude discrepancy between simulations and data here: lenses are ten times less efficient in CDM simulations than in the data! After ruling out issues with the simulation or data resolution, this leaves us with two possibilities: 1) We have a poor understanding of the interplay between DM and regular matter in the cluster cores, or 2) there are deeper problems with the CDM paradigm! This is exciting, Natarajan explained, since gaps like these (see: Mercury’s orbit and General Relativity) sometimes lead to discoveries of new physics. With even better simulations being developed and many space-based missions on the horizon (such as JWST, Roman, and Euclid), Natarajan concluded this is an exciting time to be stress-testing CDM.

Live-tweeting by Luna Zagorac

Press Conference: Evolving Stars & Nebulae II (by Abby Waggoner)

Pulsar PSR B2224+65, as presented by Daniel Wang.

The final press conference of AAS 237 was the second set of briefings on evolving stars and nebulae. The session began with Dr. Daniel Wang, from the University of Massachusetts, Amherst. In this talk, Dr. Wang discussed the pulsar PSR B2224+65 (image to the right), which had a strange jet (in the green box) pointing in the “wrong” direction. Using X-ray light, hot energetic particles were detected in the jet, suggesting that the jet’s unanticipated direction could be caused by magnetic fields. Press release

RGB image of the Butterfly Nebula, which shows extinction due to dust. [STScI, APOD/J. Schmidt; J. Kastner (RIT) et al.]

The final presentation of the press conference was given by Dr. Paula Moraga Baez, from the Rochester Institute of Technology, and Dr. Jesse Bublitz, from the Green Bank Observatory. Dr. Moraga Baez and Dr. Bublitz told us about recent observations and measurements of the NGC 7027 nebula (shown in the cover image). Perhaps most notably, they discussed the observations of CO⁺ — which represents the first mapping of CO⁺ in a planetary nebula and only the second CO⁺ map of any object. CO⁺ is significant because it can tell us about the physics and chemistry in NGC 7027 when observed together with molecules such as H₂ and HCO⁺. Press release

Lancelot M. Berkeley Prize: H0LiCOW! Cosmology with Gravitational Lens Time Delays (by Gourav Khullar)

The last plenary talk for the meeting was by Prof. Sherry Suyu (Max Planck Institute for Astrophysics), winner of this year’s Lancelot M. Berkeley − New York Community Trust Prize for Meritorious Work in Astronomy (Berkeley Prize). 

Prof. Suyu started the plenary session by thanking her H0LiCOW collaborators and family for this prize, and she then jumped into an introduction to the concept of the Hubble constant, the expansion of the universe, and how measurements of this cosmological parameter have spanned decades, with different levels of precision. She also discussed the H₀ tension — the tension that exists between a direct local measurement of H₀ via the cosmic distance ladder (with Cepheid stars), and another measurement via the early-universe cosmic microwave background. Following this, the introduction to gravitational lensing via accessible examples (see the example in the image below) was a great precursor to the science of galaxy- and cluster-scale lenses.

Example of how strong gravitational lensing works, using a candle as a background source and a wine glass as the lens.

Prof. Suyu then shared her work as part of the H0LiCOW (H₀ Lenses in COSMOGRAIL’s Wellspring) collaboration, where the objective has been to use six lensed quasars (and measurements of quasar variability from different images) to measure gravitational lensing time delays. Mathematically, time delay measurements involve the Hubble constant, which makes this methodology an independent means of measuring H₀ (with ~2.4% precision) that could potentially solve the H₀ tension. Prof. Suyu shared the work that her team has done to track a single quasar (and all its lensed images) across two decades, and the associated results from high-cadence (daily) and high signal-to-noise-ratio measurements of flux from this object, with huge success. 

The latest results from H0LICOW.

Prof. Suyu also talked about the HOLISMOKES (Highly Optimised Lensing Investigations of Supernovae, Microlensing Objects, and Kinematics of Ellipticals and Spirals) collaboration, which is specifically interested in studying the progenitors of Type Ia supernovae (like SN Refsdal) as well as measurements of H₀. Finally, Prof. Suyu gave a nod to future facilities like JWST and Rubin Observatory — which will generate a sample of quasars on the order of ~100 — that can allow us to study the above phenomena from a statistical perspective.

Interview with Sherry Suyu by Gourav Khullar
Live-tweeting of the session by Tarini Konchady

Closing Remarks (by Briley Lewis)

Astronomers gather over zoom to wrap up a great week of #AAS237!

To wrap up the week, AAS President Paula Szkody (University of Washington) and AAS Executive Officer Kevin Marvel said a quick few words. (Unfortunately, there can’t be a big closing reception with free food per usual! Hopefully in 2022!) They announced that the format for the AAS 238 meeting this summer is still to be determined, depending on the COVID-19 situation. They also thanked the large number of people that it takes to make this conference happen: the attendees, the volunteers, the session chairs, the Chambliss judges, the coordinators, the exhibitors, the sponsors, everyone involved! Kevin Marvel emphasized that “there’s no way we can have a conference without attendees” and this virtual conference brought together a lot of people, some of whom wouldn’t have been able to join in person. That brings us to the end of this whirlwind week of science — thanks for following along with Astrobites!

Editor’s Note: This week we’re at the virtual 237th AAS Meeting. Along with a team of authors from Astrobites, we will be writing updates on selected events at the meeting and posting each day. Follow along here or at astrobites.com. The usual posting schedule for AAS Nova will resume on January 19th.

Royal Astronomical Society (RAS) Gold Medal in Astronomy: A Schematic Model for Black Hole Growth and Galaxy Quenching (by Haley Wahl)

The spiral galaxy NGC 1559 is an example of a local star-forming galaxy. [NASA/ESA/Hubble]

Dr. Faber focused her question on a specific kind of galaxy: middle-sized galaxies like our own Milky Way. In the current paradigm for these galaxies, their quenching is thought to be caused by feedback from accreting central supermassive black holes, and that feedback is ejective (e.g., by blowing out the gas), preventative (e.g., by heating up the gas), or both. Black holes grow at the centers of galaxies during their formation; the black hole has little effect when a galaxy is young and the black hole is small, but eventually the black hole becomes massive enough to affect the galaxy itself and cause its star formation to quench. It is possible that the growing black hole at the center of the galaxy affects the gas in the halo surrounding the galaxy and alters its ability to cool and fall in. There are a few unanswered questions in this process, such as what the rules are for black holes growing in mass, the nature of black hole feedback, how that feedback interacts with gas in the galaxy, the origin of black hole scaling laws, and what exactly happens when galaxies start to quench. There is a lot left to understand.

Scaling laws are extremely important for answering these questions. Dr. Faber related galactic scaling laws to the zero-age main sequence for stars, which, when understood, unlocked the sequence of nucleosynthesis and how stars shine. By understanding the equivalent scaling laws for galaxies, we can understand how they evolve and how their star formation quenches. She then presented five relations: stellar mass vs. halo mass, mass vs. star formation rate, galactic radius vs. stellar mass, central stellar density vs. stellar mass, and black hole mass vs. central stellar surface density. By examining all of these relations — and how they relate to each other — we can learn a lot about how galaxies are quenched. One very important aspect of this process is the boundary between star-forming and quenched galaxies, and what happens when a galaxy crosses it in a given relation, suggesting the conditions are right for quenching.

What causes this quenching boundary and why does it move? pic.twitter.com/TudLbeLwDF

— astrobites (@astrobites) January 14, 2021

These scaling relations are starting to reveal the nature of galaxy evolution, and how the different variables come into play. One interesting point we have learned from all this is that the connection between dark matter halos and black holes is incredibly tight. There are still many unsolved questions about galaxy quenching, but more advanced modeling is getting us closer to answering the question of how and why galaxies stop forming stars!

Live-tweeting of the session by Haley Wahl

Special Session: What to Expect Under a Biden-Harris Administration (by Briley Lewis)

This special session, composed of panelists with experience in a variety of science policy roles, was held to discuss “the upcoming presidential transition and what we can expect during the first months of the new administration.” Panelists included Joel Bregman (University of Michigan), Jack Burns (University of Colorado, Boulder), Dahlia Sokolov (no affiliation), and Mike Holland (University of Pittsburgh), and the panel was moderated by Joel Parriott (AAS Director of Public Policy) and Kelsie Krafton (AAS Bahcall Fellow).

Although President Elect Biden has assembled a transition team, the transition process has been slow to start due to resistance from the current administration. There are also many other committees and groups that deal with NASA, NSF, NIST, and the DOE: the House Committee on Science, Space, and Technology, the Senate Committee on Commerce, Science, and Transportation, the House and Senate Appropriation Committees, the House Committee on Energy and Commerce, and the Senate Committee on Energy and Natural Resources. The American Institute of Physics (AIP) also has tools for tracking the federal science budget and new appointments & nominations.

Since the transition team relies on advice from a number of parties, the AAS has already sent letters to the NASA transition team and the NSF transition team. Burns reported that he also made two recommendations to the transition team: don’t completely change the scientific agenda, and work on increasing the NASA budget to $25 billion (or at least avoiding cuts to NASA/NSF). Although changes in policy and priorities are to be expected for any change in administration, Burns emphasized that stark changes in scientific agenda creates uncertainty, both within NASA and with international partners, and impedes progress, saying, “Let’s build on infrastructure we already have in place.”

A participant brought up the question of how we can reduce this uncertainty, possibly creating mechanisms for longer-term commitments to projects and making it easier for international partners to commit and fund partnerships. Although multi-year appropriations are often suggested as a solution to this problem, the panelists emphasized that there is also a lot that scientists involved in major projects can do to increase stability, such as setting clear, stable science priorities, improving project management, and controlling budget overrun.

With another stimulus package likely coming soon, the panelists were asked how this spending would affect science. A certain amount of money should be allocated for “research recovery funds” (including a stimulus for NASA) and Sokolov commented that currently the biggest risk is not to the science goals, but to the pipeline of researchers. With postdocs in limbo, students unable to graduate, and hiring freezes, she expressed worry over a possible loss of talent. (The AIP has also put out information on how COVID-19 is affecting the sciences.) Science education is also likely to be an area of interest for the incoming administration, which has placed emphasis on diversity, equity, and inclusion, as well as affordability issues both at the undergraduate and the graduate levels.

The Endless Frontiers Act is a recently introduced piece of legislation from Sen. Chuck Schumer that proposes changes to the NSF. Someone in the Q&A session raised concern that if funding is split between basic and applied sciences without a significant increase in the overall budget, it would lead to a major decrease in basic science support. Although there is a “legislative firewall” built into the legislation, Sokolov warned that those measures can be essentially ignored by an appropriations committee, so this proposal needs careful consideration of how it would change normal NSF operations. Burns added that the NSF is governed by the National Science Board, which generally helps to moderate and implement changes to the agency.

Participants also questioned when the announcement of a new NASA administrator is expected. Although no timeline was given, the panelists expressed the hope for a choice sooner rather than later, and Burns stated that the administration is looking to hire the first woman administrator to NASA, with some very qualified names already put forward for the position. Additionally, panelists discussed the Artemis mission, tasked with landing “the first woman and next man on the Moon by 2024.” Burns expressed doubt that the 2024 goal would be met, calling it “very unlikely” since the budget doesn’t accommodate for developing human landing systems. However, he was hopeful that private companies would work on this goal, too, mentioning that Jeff Bezos and his company Blue Origin have stated that they will go to the Moon whether or not NASA does. In response, participants expressed concerns about private interests setting priorities for space exploration, mentioning the small satellite problems (which will be discussed further in a later session today!).

Press Conference: Galaxies & Quasars II (by John Weaver)

The first press conference of Day 4 of AAS 237 continued the theme from earlier — galaxies and quasars. Four scientists were featured in the hour-long conference, each presenting a different aspect of galaxy evolution.

First up was Adi Foord from Stanford University, who discussed her work on supermassive black holes. When galaxies collide, we can see what happens on large scales using optical and X-ray imaging. But what happens to the supermassive black holes that reside at their centers? In what’s known as the “final parsec problem”, theory predicts that pairs of inspiralling supermassive black holes may stall out, never getting close enough to merge. However, Dr. Foord points out, this problem is mitigated when there is a third black hole involved in the merger, due to the faster circularization of their orbits. Finding collisions of three galaxies, whose supermassive black holes may actually merge quickly, is therefore of interest. Dr. Foord and collaborators used SDSS imaging to pick a handful of promising galaxy triple mergers, and then used Chandra to locate the X-ray-bright black holes. They confirmed four probable double black hole mergers and one triple merger. They also found that the dust and gas in these merging galaxies is enormous, and it’s significantly higher in the group of galaxies with the triple black hole merger. Press release

Incredibly, they can see the same shells seen by Hubble, but using amateur telescopes with longer observation times! #AAS237 pic.twitter.com/eCwtB0apvl

— astrobites (@astrobites) January 14, 2021

Next in the line up was Duilia de Mello (Catholic University of America) to talk about the Deep Images of Mergers or DIM Project. She has teamed up with a group of amateur astronomers in Brazil who use their own telescopes to image galaxy mergers. The crazy part is that they have been able to combine their efforts to match images taken in space by Hubble! By spending longer (41 hours!) observing with common amateur telescopes using extremely broad filters, they are able to cheaply image extremely faint features of galaxies — in particular, the tidal and shell features surrounding spheroidal galaxies, which are typically associated with galaxies that have recently undergone a major merger. These images can help us to understand the chaotic lives of these galaxies. De Mello is now gearing up to conduct a massively larger campaign to image the faint features of many other galaxies using the awesome power of amateaur astronomers! Press release

Magnetic fields in Messier 82, or the Cigar galaxy, are shown as lines over an optical/infrared composite image of the galaxy. [NASA, SOFIA, L. Proudfit; NASA, ESA, Hubble Heritage Team; NASA, JPL-Caltech, C. Engelbracht]

Continuing on the theme of magnetism was Alejandro Borlaff (NASA Ames Research Center) who discussed groundbreaking insight into the magnetic fields in the disk of the Whirlpool Galaxy (M51; see the cover image at the top of today’s post) using the HAWC+ instrument aboard NASA’s SOFIA observatory (the one that’s an airplane!). Previous studies of magnetic fields in galaxies explored how the magnetic field structure interacts with the filaments of gas, and in turn how that can affect or regulate star formation. However, these studies were done at bluer wavelengths that we can measure from the ground, and they mapped the magnetic fields of the diffuse gas and then assumed a similar behaviour from the cold molecular gas, from which stars can form. SOFIA is special because it flies at the edge of space, which means it can observe far-infrared light that is absorbed by our atmosphere. By directly measuring the magnetic field associated with the cold molecular gas, Dr. Borlaff and his team were able to identify differences between the magnetic fields of the diffuse and molecular gas, meaning that much of what we thought we knew about magnetic fields and star-formation will have to be re-written. Press release

NOIRLab Town Hall (by Gourav Khullar)

In this town hall, NOIRLab (the National Optical-Infrared Astronomy Research Laboratory) leadership discussed its missions, updates and future plans, with the session titled “Enabling Breakthrough Discoveries for a Diverse and Inclusive Community.” The mission statement of NOIRLab — which is the umbrella organization unifying all NSF night-time optical/IR facilities into one — is to enable discoveries with observatories, and to develop data products and services for an inclusive astronomy community. The organization wishes to be an agent of change in the community via their projects, facilities, and modes of engagement. 

The team at NOIRLab.

In this session, we heard updates from:

1. Gemini Observatory (and their new networks to coordinate observations of target-of-opportunity events, and adaptive optics and radial velocity measurement instruments)
2. Vera C. Rubin Observatory (and their operations, plans for first light in October 2022, and community engagement plans)
3. Community Science and Data Center (CSDC; which will manage their new dual-anonymous proposal system, open-access time with Keck Observatory consisting of 40 nights over 4 years, and the Astro Datalab data query and analysis service)
4. Mid-scale observatories (like CTIO in Chile and operations with its 4-m Blanco telescope, and Kitt Peak National Observatory and its new DESI survey). 

For the fiscal year 2021, NOIRLab will prioritise bringing the DESI survey online, expanding imaging capabilities, strengthening relationships with local communities, and building a program to protect dark skies from light pollution and satellite constellations. 

Live-tweeting of the session by Gourav Khullar
Twitter thread by NOIRLab

Plenary: Thermal-IR Astronomy: Progress & Future Prospects (by Abby Waggoner)

The structural components of an AGN. Matter orbiting the black hole forms an accretion disk. There is also a torus, a donut-shaped cloud of neutral gas and dust, that could obscure the light emitted by the disk. [Aurore Simonnet, Sonoma State University]

Unfortunately, it is difficult to obtain a high enough resolution when observing AGN to fully understand the relationship between the torus and the black hole. It turns out, protoplanetary disks can be used as an initial guide to AGN physics. This comparison provides a new way of interpreting AGN physics, but there are many different types of AGN. For example, some have jets and some have scattered or transmitted light,  while others do not. The one common component between all AGN is the presence of a dust molecular torus. This theory, known as the Uniform Theory, suggests that the torus plays a key role in the bright AGN emission. But,  what exactly is that role? And what exactly does the torus look like? 

To answer these questions, we turn to infrared astronomy. Light emission from the torus peaks in mid-infrared light (MIR), meaning the torus is easiest to observe in MIR wavelengths. Initial models, shown in the left figure above, from Pier & Krolik (1992) and Pier & Krolik (1993) suggested that the torus was a smooth and homogeneous distribution of gas and dust, but this model was unable to accurately match observations. Thankfully, Sptizer and Gemini provided the data needed! The data combined from these telescopes led to the Clumpy Torus model (shown in the right figure above), which suggests that the torus is full of lots of individual clouds, rather than a single continuous disk. 

Now with high resolution images and an accurate model of the torus, Dr. Packham and his team moved on to longer wavelengths to get a better picture of the entire torus. Combining observations across many wavelengths gives us a better sense of everything going on. Imagine only being able to see things that are blue, but having to figure out everything in a room. If you could also see red, yellow, and purple, you would get a much better idea what all is in the room. As promised, observations with SOFIA and ALMA further confirmed the clumpy model while better defining the structure of the torus. 

Now, what does the future hold for AGN and the torus? Dr. Packham tells us there is still much to learn. The science team is currently working on a new MIR camera called MICHI, and when MICHI and JWST (launching October 2021!) observations are combined in the future, we will gain higher resolution images and spectra, be able to trace thermal disk emission to potentially probe forming planets, probe snow lines, and even detect complex organic molecules. 

Live-tweeting of the session by Briley Lewis

Special Session: Astronomy and Satellite Constellations (by Briley Lewis)

This November 2019 image is from the Dark Energy Camera on the Blanco 4-m telescope at Cerro Tololo Inter-American Observatory in Chile. It reveals the trails of 19 Starlink satellites that passed through the survey’s field of view during the six-minute exposure. [NSF’s National Optical-Infrared Astronomy Research Laboratory / CTIO / AURA / DELVE]

To address these challenges and inform policy decisions, astronomers and satellite operators have collaborated to mitigate the effects of these satellite constellations. In the past few years, the NSF and AAS hosted the SATCON1 workshop, culminating in a report on impacts and mitigation strategies, and the IAU and partners hosted the Dark and Quiet Skies workshop, creating a report to be presented to the UN Committee on the Peaceful Use of Outer Space. The AAS also maintains a Committee on Light Pollution, Radio Interference, and Space Debris. In today’s session, astronomers and satellite operators met once again to discuss these issues and increase awareness of these issues with AAS members.

When SpaceX’s Starlink satellites first went up, many people panicked upon seeing images of the night sky filled with bright streaks. Panelist Patrick Seitzer (University of Michigan, Ann Arbor) reported that the AAS has set a goal for these satellites to stay at magnitude 7 or fainter; that is, they shouldn’t be visible to the naked eye in excellent dark sky conditions. There’s a caveat to this though: objects further away may look fainter to our human eyes, but an object in a higher orbit is actually in better focus for a telescope and has a longer travel time (thus, exposure time) across a detector, causing more problems for astronomy. As a result, the AAS additionally recommends that these satellites stay below 600 km.

Plot of number of satellites visible over the course of a night. Blue points show satellites at 1,000 km, orange at 500 km. [Patrick Seitzer]

Two of Starlink’s mitigation strategies described by Patricia Cooper. [SpaceX]

Responding to questions about international coordination of mitigation efforts, panelists suggested that the orbital debris tracking community could be a good example to look to. As Jeff Hale aptly said, “Lots of people are trying to get into the game, and bad things will happen if they just don’t care.” Hopefully, the satellite operators will continue to consider astronomy and other impacts in their plans, and these conversations between stakeholders will continue as well.

Press Conference: Evolving Stars & Nebulae I (by Ellis Avallone)

Image of an astronomical log book from 1945. These observations are now part of the Digital Access to a Sky Century at Harvard, or DASCH, catalog. [DASCH/Harvard University]

Next, Ethan Kruse from NASA Goddard SFC told us about how we can use machine learning to discover eclipsing binaries in survey data. We have the best chance of detecting lots of eclipsing binaries when we look at the sky for a long time, i.e., with survey telescopes. While Kepler helped us out a ton with getting binary light curves with long baselines, it only looked at a small patch of the sky. The TESS mission, Kepler’s younger sibling, is an all-sky survey that can give us an orders-of-magnitude larger sample than Kepler. The machine learning pipeline developed by Kruse and his team has already detected 20,000 eclipsing binaries in TESS data within their small test sample. As the TESS mission continues, we expect to add tens of thousands of these interesting systems to our current sample.

Hubble 5 is a striking example of a “butterfly” or bipolar (two-lobed) nebula. [Bruce Balick (University of Washington), Vincent Icke (Leiden University, The Netherlands), Garrelt Mellema (Stockholm University), and NASA]

The last two talks were all about supernova remnants. First, Dan Patnaude (Center for Astrophysics | Harvard & Smithsonian) talked about the connection between supernova remnants and the supernovae that formed them. Although we have very few examples where we’ve observed both supernova and remnant, a recent detection caught the eye of Patnaude and his team. SN1996cr is located in the nearby Circinus galaxy, and although the initial supernova wasn’t observed in detail, archival data has assisted tremendously in characterizing this object. Patnaude has been able to effectively look back in time with this object, even without perfect observations.

Hubble view of supernova remnant 1E 0102.2-7219. [NASA, ESA, STScI, and J. Banovetz and D. Milisavljevic (Purdue University)]

Live-tweeting of the briefing by Ellis Avallone

Dannie Heineman Prize for Astrophysics: The All-Sky Automated Survey for Supernovae (by Mike Foley)

The final plenary talk of the day was given by Chrisopher Kochanek (The Ohio State Univ.), this year’s recipient of the Dannie Heineman Prize, an award that recognizes outstanding mid-career work in the field of astrophysics. Dr. Kochanek is one of the architects of ASAS-SN, the All-Sky Automated Survey for Supernovae. ASAS-SN is fully automated and can observe and identify transient objects without human intervention. A transient object is anything that changes substantially in the sky over time; asteroids, cataclysmic variables, novae, and supernovae are the most common. By taking a large number of images across the sky and comparing images of the same region over time, ASAS-SN can identify what changes between images. 

To do this, ASAS-SN doesn’t need large telescopes. In fact, their network of telescopes features individual mounts that have four lenses, each only 14 cm in diameter. By distributing these mounts around the world and continually monitoring the sky, ASAS-SN aims to serve as the “first responder” when a transient event occurs. Once ASAS-SN reports on a transient event, it can be followed up by larger telescopes for further study. Dr. Kochanek noted that amateur astronomers also play a large role in detecting and following up on transient events! ASAS-SN has historically done better at detecting supernovae closer to the centers of their host galaxies (the galaxy in which the supernova went off) than both amateur and professional surveys. 

This artist’s concept depicts “heartbeat stars”. [NASA/JPL-Caltech]

Finally, ASAS-SN also provides a remarkable amount of data for static sources, such as normal stars. Later this year, Dr. Kochanek and collaborators will release Sky Patrol 2.0, which will feature continuously updated light curves for 106 million stars! ASAS-SN has been one of the leaders in promoting open data, creating a full database for users to query light curves observed by ASAS-SN. Thanks to Dr. Kochanek and the ASAS-SN team, the night sky is being well-monitored. 

Live-tweeting of the session by Abby Waggoner
Interview of Chrisopher Kochanek by Ellis Avallone

Editor’s Note: This week we’re at the virtual 237th AAS Meeting. Along with a team of authors from Astrobites, we will be writing updates on selected events at the meeting and posting each day. Follow along here or at astrobites.com. The usual posting schedule for AAS Nova will resume on January 19th.

Henry Norris Russell Lectureship: Comets, Unseen Planets, and the Outer Fringes of the Solar System (by Haley Wahl)

The first plenary of the third day of AAS 237 was given by Scott Tremaine of the Institute for Advanced Study, who gave the Henry Norris Russell Lecture, an honor awarded to a scientist on the basis of lifetime eminence in astronomical research. His talk focused on one of his many interests: comets. Dr. Tremaine started off by giving a brief overview of comets, which are chunks of rock and ice with a radius of a few kilometers. They are thought of as “rubble piles” because of their low density and are believed to be leftover small bodies from the formation of our solar system. Atmospheres (coma) and tails appear when a comet approaches the Sun and once a comet becomes visible, it can survive for more than 100 orbits. 

Dr. Tremaine then dove into discussing the energy of comets and how we can predict where comets will be and where they come from by looking at how much energy they have when passing through our solar system. He then spoke about the Oort Cloud, a region far beyond the orbit of Pluto where a lot of comets are thought to originate. The Oort Cloud is far enough from the Sun that kicks from passing stars and torques from galactic tides can mess with the orbits of the comets in the Cloud, meaning that comets can be removed from it. There is a standard model of the formation of the Oort Cloud, which contains assumptions and initial conditions for how comets form. By using that theory and doing simulations, astronomers can pretty well determine the properties of the inner Oort Cloud. Like the standard model for particle physics, the standard model for the Oort Cloud isn’t perfect. 

There are parallels between the standard model of particle physics and the standard model of comets! pic.twitter.com/xSlZanYDDH

— astrobites (@astrobites) January 13, 2021

Orbit of the comet Sedna.

The final part of Dr. Tremaine’s talk focused on the possibility of another major solar system body existing, an idea motivated by comets on very large orbits — for instance, Sedna!

Sedna and others like it do not follow the standard model … so how did they end up on their current orbits? The standard model is based on the planets and many test particles, so maybe it is oversimplified and we should factor in things like kicks from passing stars and the galactic tide to explain comet orbits. Simulations show that there is a possible undiscovered planet that is ~0.1–1 solar mass that is within 250 au of the Sun, nicknamed “Planet X” (this concept is also sometimes referred to as “Planet Nine”). There is a lot of speculation about whether or not Planet X exists and, if it does exist, where it came from.

There has been a lot of speculation about Planet X, here is a little bit more information! pic.twitter.com/hE3WSCoJU4

— astrobites (@astrobites) January 13, 2021

Dr. Tremaine ended his talk by summarizing that the standard model of the formation of the Oort Cloud explains most but not all properties of comets and that there are possible hidden planets out there. In the next decade, we could improve constraints on Planet X or discover it, but we will not be able to rule it out. He finished by leaving up an XKCD comic:

The realm of undiscovered planets. [XKCD]

Press Conference: Bursting Magnetars (by Ellis Avallone)

NGC 253 is a bright spiral galaxy located about 11.4 million light-years away in the constellation Sculptor. [Dietmar Hager and Eric Benson]

So-called giant magnetar flares occur when starquakes cause a magnetar’s strong magnetic field to rearrange. The Sculptor galaxy magnetar underwent such an event, producing a short burst of gamma rays that was detected by five of the satellites in the Interplanetary Network (IPN) — an array of telescopes essential for localizing gamma-ray bursts. It has long been suspected that some short gamma-ray bursts originate from magnetars, and the detection of one in a nearby galaxy confirmed this suspicion. Although giant magnetar flares represent the most extreme release of magnetic energy we observe in magnetars, we can only observe them out to about 50 million light-years. The triangulation of the signal with the IPN showed that the burst had to have come from the Sculptor galaxy. When triangulating a signal, there is always a chance of a false association, where a background signal is incorrectly associated with an object. However, the chance of this happening for this magnetar flare is about 1 in 230,000, which further confirmed the location of the flare. 

The distinct light curve of a giant flare from a magnetar includes a sudden peak followed by a long, spiky decay tail. The spikes are caused by the gradually cooling hot spot on the magnetar’s surface rotating in and out of view. [NASA’s Goddard SFC]

What does this event mean in the context of other magnetar flares? Dr. Eric Burns from Louisiana State University wanted to find out if giant magnetar flares were being buried in short gamma-ray burst signals, which more frequently originate from neutron star mergers. Although the sample of giant magnetar flares only consists of a handful of events, it is large enough to provide insight into the occurrence rates of these events. With this information, Burns and his team determined that giant magnetar flares occur more frequently than supernovae, at least in the local universe.

Finally, Dr. Victoria Kaspi from McGill University commented on this result and what it means for other areas of astronomy. Most notably, giant magnetar flares are a potential source of fast radio bursts (FRBs), whose origin is still unknown. The occurrence rate for giant magnetar flares found by Burns is consistent with FRB occurrence rates. However, more work needs to be done to confirm that FRBs originate from magnetars.

Press release for the briefing

Live-tweeting of the briefing by Ellis Avallone

STScI Town Hall (by Mike Foley)

The Space Telescope Science Institute (STScI) manages many of the space telescopes, including the Hubble Space Telescope (which has been operational since the 1990s), James Webb Space Telescope (JWST), and Nancy Grace Roman Space Telescope (the latter two of which have yet to be launched). STScI also maintains the Barbara A. Mikulski Archive for Space Telescopes (MAST), which distributes data from over 20 astronomical missions. The Town Hall today focused on a Hubble program, planning for the Roman Telescope, and recent results from an advanced optics lab.

An artist’s illustration of the James Webb Space Telescope, a joint effort between NASA, the European Space Agency, and the Canadian Space Agency. [NASA/JWST]

He was followed up by Julia Roman-Duval, who presented updates about the ULLYSES Hubble program. ULLYSES (the Ultraviolet Legacy Library of Young Stars Essential Standards), a proposed mission that will last three years, represents the largest single Hubble program (observing run) ever, and its span will include nearly 1,000 Earth-orbits of Hubble, providing observations that can be used to study both high- and low-mass young stars. Around 500 of these orbits will be used to extend the spectroscopic library of O and B stars to low metallicity. These data will give important information about the properties of these massive stars, spectral templates for certain stellar populations, chemical information, and characterization of some galaxy-scale outflows in the circumgalactic medium. The other 500 orbits will be used to study T Tauri stars in eight nearby star-forming regions, allowing for an unprecedented look into the lives of young, low-mass stars.

Illustration of NASA’s Nancy Grace Roman Space Telescope (formerly WFIRST). [NASA]

Rémi Soummer finished up the Town Hall with updates from the Russel B. Makidon Optics Laboratory, a state-of-the-art optics lab at STScI created in 2013 to advance technologies for future generations of space telescopes. Recently, they worked on a project aimed at direct imaging of exoplanets, which is extremely difficult and requires sensitive technology. Some of their recent projects are aimed at enabling direct images of exoplanets. Using their equipment, PhD student Susan Redmond recently showed that they could maintain excellent contrast in coronagraph images, even when perturbations are introduced into the system over time. The lab has made a number of student-led improvements that will be relevant to future missions, and they are now operating remotely and have developed ways to maintain experiments throughout the pandemic.

Live-tweeting of the session by Mike Foley

Plenary: Distinguishing Black Hole Binary Formation Channels With Eccentricity Measurements and Other New Gravity Wave Probes (by Luna Zagorac)

The second plenary of the day, re-named “What (Else) Can We Learn About Binary Black Holes?,” was given by Professor Lisa Randall of Harvard University. She noted that the work she was presenting was done with Professor Zhong-Zhi Xianyu of Tsinghua University, as well as with students Alexandra Shelest and Nicholas Deporzio. Dr. Randall started off by introducing a particle physicist’s approach to a particular astronomical data set: LIGO’s observations of stellar-mass black hole mergers via gravitational waves! Data sets in particle physics are scarce, Randall argued, so we eke out the most physics possible from them — and we should do the same with LIGO’s data. With this in mind, what new information can we learn from LIGO data? Randall refers to this approach as BSA: Beyond Standard Astronomy.

The dense and chaotic cores of globular clusters, as shown in this simulation still, may provide an ideal environment for black holes to interact dynamically and merge. [Carl Rodriguez/Northwestern Visualization]

Thankfully, there is a mechanism that produces extremely eccentric orbits, called Kozai–Lidov. It is a feature only of the three-body system, making it extremely interesting for probing the dynamic formation channel when used with eccentric gravitational wave events such as GW190521. Furthermore, the launch of the gravitational wave observatory LISA will help the situation in two ways.

Artist’s impression of the Laser Interferometer Space Antenna (LISA). [NASA]

Second, binaries that start with small eccentricities will be imaged with both LIGO and LISA, allowing us a multichannel view of the merger. In contrast, binaries with large eccentricities will only be seen in a single channel, thus allowing us to discriminate between dynamic and other formation channels. Ultimately, this may mean determining the origins of stellar-mass black hole binaries!

Live-tweeting of the session by Luna Zagorac

Press Conference: Dizzy with Data for DESI (by John Weaver)

The second press conference of the day was all about the Dark Energy Spectroscopic Instrument Survey, or DESI for short. The DESI Survey is conducted at the Mayall 4-meter telescope at Kitt Peak National Observatory and has been running since 2019. Its goal is to map the universe to better understand the nature and origin of, well, dark energy. But as we will see from the press conference today, whenever we peer into the night sky we find lots more than we bargained for. What more could we want? The Data Release 9 is out today.

Co-Project Scientist David Schlegel (Lawrence Berkeley National Laboratory) started us off with a brief overview of the survey. The DESI survey works by first collecting an incredible amount of images of the sky. A team of 150 astronomers help to condense 1,400 nights on 3 telescopes totalling a whopping 1 petabyte of data into vast maps of the night sky. They are aided by immense computing power with over 100 million supercomputer hours spent just on DESI. You can view the polished images here. Although the survey is not yet complete, there are already many exciting discoveries being made. Press release

Lots of fascinating "discoveries waiting to happen" in these images. These will be the focus of another talk in the conference! Have a look at this "galaxy-sized telescope" which helps us peer into the more distant universe. #AAS237 pic.twitter.com/VDbRuZ3Hhn

— astrobites (@astrobites) January 13, 2021

Strong gravitational lenses help magnify distant background galaxies using the power of gravity. Xiaosheng Huang (University of San Francisco) explains that thanks to the DESI area, they are able to find many more of these incredibly rare lenses, affording new opportunities to explore the very distant universe. These “galaxy-sized telescopes” are bulked up by their massive dark matter halo which helps bend light from more distant background galaxies. Since there may be many images of the background galaxy caused by light traveling along different paths around the lensing galaxy, one unique application is to study supernovae by measuring the time delay between the supernovae seen in the duplicate images. This can ultimately help us to understand the nature of cosmic expansion. Press release

They now have the BEST EVER 3D map of brown dwarfs in the solar neighborhood. Incredible, with lots of discoveries to come. #AAS237 pic.twitter.com/bl1PFJZ8TP

— astrobites (@astrobites) January 13, 2021

Cold brown dwarfs are some of the most bizarre and yet fascinating sub-stellar objects in the universe. Aaron Meisner (NSF’s NOIRLab) has collaborated with a huge team of citizen scientists through the Backyard Worlds: Planet 9 project, launched in 2017 at Zooniverse, and has since collected more than 7 million user ‘classifications’ from 150,000 contributors. The result? They have constructed the most complete 3D map of brown dwarfs in the solar neighborhood, selected from images from NASA’s WISE satellite together with the data from DESI. Predictions suggest that our solar neighborhood should host a variety of stellar types, brown dwarfs included. However, the results from Backyard Worlds suggest otherwise: they find the nearest brown dwarf seriously far away at 7 parsecs distance. That may mean that our solar neighborhood is tantalizingly devoid of brown dwarfs, or they’re possibly just too faint to be detected. The citizen scientists not only get to share in the limelight of the discovery, but they have the opportunity to work on projects connecting them to some of the premier facilities in all of astronomy. Press release

This is only a very small portion of the total @desisurvey data footprint. So many galaxies! DESI helps by adding even more spectroscopic redshifts to help pin down their distances. #AAS237 pic.twitter.com/SKP0C2OZ21

— astrobites (@astrobites) January 13, 2021

Black holes in galaxies also seem to be missing. The X-ray emission from all of the monster black holes found so far doesn’t add up to what we see from the cosmic X-ray background. Stephanie Juneau (NSF’s NOIRLab) has worked to correct this dire picture. By using the incredibly wide imaging from the DESI survey, she and her team have tracked down some of these missing black holes. The trick? Combining multiple imaging surveys with spectroscopic follow-up. This way they can identify candidate black holes from the images and then use DESI spectroscopy to confirm them. But the X-ray emission from black holes likes to ‘flicker’ on and off, making them even more difficult to find. If the survey can confirm all of their candidates, Juneau and her team can better understand how often black holes flicker, which has the potential to impact how we understand the growth of black holes and their connection to their host galaxies.

Live-tweeting of the briefing by John Weaver

Annie Jump Cannon Award in Astronomy: Hazy Views of Nearby Worlds: Standing Between Two Eras of Exoplanet Characterization (by Michael Hammer)

Artist’s illustration of NASA’s TESS mission observing a system of transiting exoplanets. [MIT]

The three-part overarching goal driving the field of exoplanet atmospheres is to find molecular biosignatures in the atmosphere of an Earth-like planet around a solar-type star. Before we can do that though, we had to start out by making concessions on all three parts. Most studies of exoplanet atmospheres are based on transmission spectra (see Morley’s own bite for an overview, and here and here for more recent updates) that are taken as a planet transits in front of its star. Similar to the limitations of detecting planets through transits, planets that produce deeper transits yield better-resolved spectra, making it easier to detect features in atmospheres of planets bigger than Earth or around stars smaller than the Sun. Meanwhile, planets that have thicker atmospheres (>1% by mass) than Earth (0.0001% by mass) are also easier to resolve. Beyond just biosignatures, we want to characterize what planetary atmospheres are made of in general.

Artist’s impression of a cloudy exoplanet. [NASA/ESA/G. Bacon, STScI/L. Kreidberg and J. Bean, University of Chicago/H. Knutson, Caltech]

Beyond planets, another focus of Morley’s research has been brown dwarfs. The atmospheres of free-floating brown dwarfs are easier to resolve than those of planets around stars because their spectra are not contaminated by nearby starlight. And, more importantly, they may shed some insight on what planetary atmospheres are like because the coldest ones that we only started discovering this past decade (Y-type) have similar temperatures to planets — at least one is even colder than the Earth! Morley and her collaborators have shown that the atmospheres of Y dwarfs can have thick methane hazes and be out of equilibrium.

Sounds exciting? The AAS certainly thinks so, in that they decided to give next year’s Annie Jump Cannon Award to one of Morley’s collaborators: Laura Kreidberg. Stay tuned for more developments in the field of exoplanet atmospheres — TESS and JWST will certainly provide them!

Interview of Caroline Morley by Briley Lewis
Live-tweeting of the session by Michael Hammer

Hearing the Light: How Sonification Makes Astronomy More Accessible (by Abby Waggoner)

Clara Braseur (Space Telescope Science Institute) & Jenn Kotler (Space Telescope Science Institute) hosted this afternoon’s session on sonification.

As beautiful as the images, plots, and figures we use for astronomy are, visual based astronomy presents a barrier for individuals who have visual impairments or are blind. Sonification is a process that converts visual images into sounds, thus making astronomy more accessible. For a (really awesome) example, check out this NASA website for some examples that bring three astronomical objects to our ears. 

Not only does sonification make astronomy more accessible, but it also presents a new method of interpreting data. Our eyes are able to process roughly 100 frames per second, whereas our ears are able to process over one million frames per second, thus detecting information that our eyes may have missed. We are also able to filter out background sounds and noise more easily in audio rather than visual form a phenomenon known as the cocktail effect — which can make finding patterns in noisy data much easier. 

Sonification is a really cool method, but how does one go about doing it? Thanks to the program Astronify, sonification of your own data is super easy to do. Astronify is a python based code and can be installed on any computer for free using a simple installation command. You simply give it a table of data, such as flux and time, and let it run! Astronify is currently ideal for sonifying lightcurves, spectra, or any other 2D plot, but the Astronify team is working on introducing more dimensions and error bars on the sounds. Check out the two videos below for the sonification of lightcurve with no flare and a lightcurve with seven flares using Astronify. 

Sonification is an exciting tool we can use to make astronomy more accessible, and thanks to Astronify, it is becoming a process we can apply to our own data.

Editor’s Note: This week we’re at the virtual 237th AAS Meeting. Along with a team of authors from Astrobites, we will be writing updates on selected events at the meeting and posting each day. Follow along here or at astrobites.com. The usual posting schedule for AAS Nova will resume on January 19th.

Plenary: Prize Presentations (by Abby Waggoner)

Day two of AAS 237 began with a brief overview of outstanding astronomers and the awards they received for their contribution to the field. All of the awardees are listed in this twitter thread, along with a description of the awardees’ accomplishments. Awards ranged across all fields of astronomy, including instrumentation, theory, education, writing, and more. Congratulations to all of the awardees!

Live-tweeting of the session by Abby Waggoner

Plenary: A New Era for Galactic Dynamics in the Milky Way (by Briley Lewis)

This morning’s first plenary was from Adrian Price-Whelan (Flatiron Institute), astronomer and astropy developer. He opened with a message that likely resonated with many of us, acknowledging how difficult the past year has been and how hard it is to work and be productive. “It’s okay if you’re unproductive, it’s okay if you’re struggling for motivation, it’s okay if you need to prioritize yourself or your family.” 

The science part of this talk focused on galactic dynamics in the Milky Way. With all the surveys of Milky Way stars from the past few decades, we have lots of data to work with. Importantly, these surveys released their data publicly and spanned many modes of observation: photometry and time-domain imaging (2MASS, SDSS, GALEX), astrometry (Gaia), and spectroscopy (APOGEE, GALAH). Gaia is of particular importance, since it has added extremely precise parallaxes and proper motions for many stars in our galaxy. With all these data we can figure out stellar parameters, elemental abundances, kinematics, and more.

This plot from Price-Whelan’s talk shows the drastic increase in the number of stars with velocity measurements between the Hipparcos mission and the new Gaia mission.

For many years, studies of the Milky Way relied on “first order” models — smooth, simplified descriptions of the galaxy. Price-Whelan showed the classic “cartoon/textbook Milky Way” with a central bar, thin disk, thick disk, halo, and dark matter halo. We already know our galaxy also has sub-galaxies (like the Large and Small Magellanic Clouds, a.k.a. LMC/SMC) and dark matter subhalos. 

Cartoon of the Milky Way showing the different features mentioned.

The velocity of the Sun in the galaxy and our distance to the galactic center are well defined, and we have a good “big idea” picture of the galaxy’s overall density, rotation curve, and velocity dispersion in the halo. But with all these new data, like what we’re getting from Gaia, those first order models just can’t keep up with the precision. Price-Whelan is interested in looking at where we see deviations in the precise data from those first order models, to investigate the Milky Way’s structure in finer detail.

This plot from Price-Whelan’s talk shows observed data from SDSS and a corresponding smooth model. The third panel, the residuals, is what Price-Whelan is most interested in studying.

It turns out that satellite galaxies and mergers are a big factor in shaping the Milky Way as we see it and causing these deviations. For example, the Sagittarius Stream (created from the Sagittarius Dwarf Galaxy) perturbed the outer parts of the Milky Way, and the Gaia-Enceladus Merger led to the thick disk that we observe. In the dark matter distribution of the Milky Way, we also see our galaxy responding to the infall of the LMC/SMC.

This comic shows the history of interactions between the Sagittarius Dwarf Galaxy and the Milky Way, tracing out the streams it left behind. [ESA; Ruiz-Lara et al. 2020]

Image showing the observed stellar streams around the Milky Way, including Sagittarius.

We can also use the motion of these satellites to investigate the structure of dark matter in our galaxy. By measuring the orbits of these thin stellar streams (from disrupted star clusters), we can trace out the acceleration field and better understand where the dark matter is. Given that all this interesting galactic science arises from publicly available data, Price-Whelan concluded by emphasizing the importance of open-source software and open science, which encourages collaboration and community building. So, put your code on GitHub! 

Interview of Adrian Price-Whelan by Michael Foley
Live-tweeting of the session by Haley Wahl
Recording of this talk and hands-on access to some of Adrian’s visualizations available on his website

Press Conference: Galaxies & Quasars I (by Haley Wahl)

Illustration of a monster black hole siphoning gas off of an orbiting giant star. [NASA’s Goddard SFC/Chris Smith (USRA/GESTAR)]

The next talk of the press conference was given by graduate student (and Astrobites author!) Gourav Khullar from the University of Chicago. He discussed COOL J1241+2219, the brightest galaxy observed from when the universe was < 1.2 billion years old. This galaxy is unique because it is near the epoch of reionization. The team found that this galaxy was consistent with a constantly star-forming galaxy and that it has formed a few times the number of stars of the Milky Way in just 1/10th the time, and at a much earlier time in the universe!

Most quasars are thought to be obscured by dust. [NASA/SOFIA/Lynette Cook]

The final talk of the press conference was given by Feige Wang from the University of Arizona, who talked about an exciting new discovery. The team announced the detection of the most distant quasar ever discovered, which is seen just 670 million years after the Big Bang and is powered by a black hole that is 1.6 billion times the mass of our Sun! Press release

Recording of the live press conference
Live-tweeting of this session by Haley Wahl

NASA Town Hall (by Mike Foley)

Today’s town hall featured a lot of exciting updates about planned missions and budgetary considerations. First up was Dr. Thomas Zurbuchen (Associate Administrator for the Science Mission Directorate at NASA), who stressed the importance of open communication between NASA and astronomers. “Science is important for all!” he said, emphasizing the necessity of connection with non-scientists as astronomers seek to publicize their work. 2021 will have many long-awaited launches and projects from NASA, and the public deserves to know about all of this cool science. 

Overall, the NASA Science Mission Directorate has a few key areas of focus for this year:

1. Promoting open science through data sharing, open-source software, and other initiatives.
2. Diversity and inclusion initiatives to “build the best teams we can.” Inclusion is now one of NASA’s criteria for evaluating mission success.
3. Assessing and mitigating COVID-19 impacts on NASA research and missions.

In addition to these areas of focus, NASA also has a large number of projects planned for 2021. Below is a breakdown of 2021 milestones for the NASA science directorates. Some major highlights include the release of the Decadal Survey in the spring, which presents an overview of the state of astronomy and astrophysics in the United States. The telescope formerly known as WFIRST was renamed the Nancy Grace Roman Space Telescope in honor of NASA’s first chief astronomer and is well into development, with a completion date scheduled for the end of 2021. The James Webb Space Telescope (JWST) will also launch later this year, revolutionizing many areas of astronomy. Finally, the Mars Perseverance rover will land on February 18th, 2021!

In terms of research, NASA has started to implement dual-anonymous peer review. Because of this, the proportion of accepted proposals with female-identifying PIs (principal investigators) is now consistent with the full application pool! There is overwhelming agreement that the dual-anonymous peer review process improved the overall quality of the peer review. Astronomy research will also benefit from a significant funding package from Congress, allocating over $500 million more than was requested and featuring significant funds for JWST, Roman, Hubble, and SOFIA. 

Live-tweeting of the session by Mia de los Reyes

HEAD Bruno Rossi Prize: Black Hole Imaging: First Results and Future Vision (by Mike Foley)

The first detailed image of a black hole, M87, taken with the Event Horizon Telescope. [Adapted from EHT collaboration et al 2019]

Since then, simulations have improved significantly, and the EHT relied extensively on large samples of simulations of black hole accretion disks to understand their results. These accretion disks are enormous — the one observed around the black hole in M87 is large enough to fit our entire solar system, even beyond the distance traveled by Voyager 1! Nevertheless, M87’s accretion disk is extremely faint when observed from Earth, and it requires incredible resolving power to see. To observe it, the EHT needed to make use of a network of telescopes all across the globe. They combined them to make one “super telescope” with an effective diameter the size of the Earth. 

Eight stations of the EHT 2017 campaign over six geographic locations. [EHT Collaboration et al 2019]

Where to go from here? More resolution! The next generation EHT (ngEHT) will add new telescopes, improve hardware, and observe at two different wavelengths. Such improvements will yield a 3–10x increase in effective resolution, allowing for observations of up to 10 more sources and even potentially enabling scientists to create movies of a black hole! According to Dr. Doeleman, “ngEHT development is underway, with the promise of a black hole cinema by the end of this decade.” Such groundbreaking results will continue to revolutionize our understanding of supermassive black holes and help define the next era of astronomy. 

Interview of Sheperd Doeleman by Gloria Fonseca Alvarez
Live-tweeting of the session by Mike Foley

Special Session: Collaboration with Integrity: Partnerships with Indigenous Communities in the Americas and Polynesia (by Luna Zagorac)

Now at #AAS237: Session 225 – Collaboration with Integrity: Partnerships with Indigenous Communities in the Americas and Polynesia.

— astrobites (@astrobites) January 12, 2021

This session was chaired by Prof. Aparna Venkatesan (University of San Francisco), who began it with a land acknowledgement for where the meeting would have been held: on the land of the Tohono O’odham Nation in Phoenix, Arizona. Prof Venkatesan further acknowledged the difficulty of the past year and the inequality that exists is society and astronomy, asking: “Can we choose a collaborative approach, rather than a transactional approach?… In gaining the stars, who are we losing?”

Afterwards, Prof. Venkatesan introduced Professor Nancy Maryboy and Professor David Begay of the Indigenous Education Institute and Northern Arizona University who spoke about Diné-Navajo astronomical knowledge. Prof. Maryboy noted that “the Diné-Navajo word for Star, Sitsoii Yoo, refers to my ancient relation from where I came…When we look at the Milky Way Galaxy at night we are actually looking at ourselves.” Prof. Begay underlined that the key words here are “ancient” and “relation,” reminding us that we are all made up of the elements of the cosmos. Prof. Begay went on to explain the connection of the hogan, the Navajo house, and the cosmos that is home to us all, noting that this is why there is no word meaning “homeless” in the Navajo language. Prof. Maryboy spoke more about heliophysics and relationships to the Sun — called Johannaa’ éí, and depicted as a man on a horse carrying the solar disk. She also spoke of the Navajo hero twins that visit the Sun, comparing them to the NASA Solar Orbiter and Solar Probe. The Navajo have a long history of discussing travelling to the Sun, she noted. 

The next speaker was Dr. Kaʻiu Kimura, Executive Director of the ‘Imiloa Astronomy Center of Hawaiʻi at the University of Hawaiʻi – Hilo. Dr. Kimura has spoken at previous AAS meetings about A Hua He Inoa, an initiative to use ʻōlelo Hawaiʻi (the Hawaiian language) in naming conventions for naming astronomical objects. Celestial nomenclature and acknowledging connections with the sky has been a part of the Hawaiian universe since the very start (see A Catalogue of Hawaiian and Pacific Star Names), and Dr. Kimura noted that “through naming, we connect to events of historical experience…Names tell stories.” Some recent examples of of using ʻōlelo Hawaiʻi include: asteroid Kamoʻoalewa, alluding to a celestial object that is oscillating, like its path in the sky as viewed from the Earth; black hole Pōwehi, an “embellished source of unending creation,” referring to the recently-imaged black hole at the center of M87; and quasar Pōniuāʻena. Kimura also shared a video of one of the 30 kumu (teachers) from Hawaiian immersion schools, who spoke about the naming as the result of relaying modern technology with 1,621-year history of Indigenous Hawaiian intelligence. Dr. Kimura also emphasized the importance of building connection and developing meaningful relationships between communities, noting that true collaboration is authentic and embraces everyone.

Finally, for the panel part of the session Prof. Venkatesan introduced the remaining panelists: Dr. Douglas Simons of the Canada-France-Hawaii Telescope, Dr. Isabel Hawkins of Exploratorium, and Dr. Laura Peticolas of Sonoma State University. While we did not cover this part of the session in detail, we will end our write-up with a note from Dr. Hawkins that was echoed by Dr. Kimura: introducing Hawaiian naming conventions goes both ways, and Western-trained astronomers can benefit greatly from learning about the language and Indigenous astronomical knowledge more generally. 

Press Conference: Sloan: The Energizer Bunny of Sky Surveys (by Haley Wahl)

The Sloan Digital Sky Survey has been mapping out the universe for more than two decades now, and it’s still going strong! Today’s second press conference focused on some of the latest results to come out of the survey.

An artistic impression based on a computer simulation of the Draco C1 symbiotic binary star system showing material flowing off the red giant star onto the white dwarf. [John Blondin, North Carolina State University]

The second speaker was Dr. Allyson Sheffield from LaGuardia Community College, who discussed new discoveries in the Jhelum stellar stream. Her team examined this stream of stars and found the brightest known member. They also were able to deduce that the Jhelum stream stars may have originated in a satellite galaxy or a globular cluster, and found that stars from the Gaia-Enceladus-Sausage merger do not appear to be associated with the Jhelum stellar stream. Press release

Left: optical image of a galaxy shown to citizen scientists. Right: the heat map of the galaxy’s internal structures collectively generated by the citizen scientists’ input. [Karen Masters (Haverford College), Coleman Krawczyk (University of Portsmouth), and the SDSS Collaboration]

The final talk of the press conference, “A Handoff from SDSS IV to SDSS V,” was given by Juna Kollmeier of Carnegie Observatories and Michael Blanton of New York University. SDSS IV is currently finishing its observations after its 6-year survey, and over the last 20 years, SDSS has made the largest 3D map of the universe, looked at over 10,000 nearby galaxies with MaNGA, and more! SDSS-V plates are currently being constructed using robots that place fibers, which will dramatically increase efficiency in the next phase of the survey. A few components of SDSS-V include: the Milky Way Mapper (which will measure stars in all stellar populations and across the galaxy), the Local Volume Mapper (which will study how stars form and exchange energy with interstellar gas), and the Black Hole Mapper (which will trace how black holes evolve on short and long timescales)!

Recording of the live press conference 

Plenary: Cosmology in the Era of Multi-Messenger Astronomy (by Tarini Konchady)

The last plenary talk of the day was given by Dr. Marcelle Soares-Santos (University of Michigan), who tackled how cosmology is changing as gravitational wave observatories come into their own. Soares-Santos is deeply involved in the Dark Energy Survey (DES), which aims to study dark energy and large scale structure to better understand the universe.

What’s the benefit to introducing gravitational wave science into cosmology? Over the past few decades, astronomers have been increasingly stymied by measurements of the Hubble constant — the rate at which the universe is expanding. Measurements of the Hubble constant from the cosmic microwave background differ significantly from those measurements made using redshifts and distances as determined by Type Ia supernovae. This is strange, because our models of the universe predict that the Hubble constant should have the same value no matter how you measure it!

Soares-Santos said gravitational wave events could provide a tiebreaker between these two measured values of the Hubble constant. The changing frequency of gravitational wave signals can give you the distance to the event, and the electromagnetic counterpart of the event would give you its redshift, allowing an independent measurement of the Hubble constant.

The Hubble constant as estimated by the event GW170817 is shown by the blue curve. The dashed lines are confidence intervals on this estimate. The green region is the Hubble constant measurement made from the cosmic microwave background and the orange region is the measurement made from the distances and redshifts of Type Ia supernovae. [The LIGO Scientific Collaboration and The Virgo Collaboration, et al. 2017]

With the electromagnetic signal of a neutron star merger in hand, Soares-Santos was able to demonstrate that combining DES data with less than ten neutron star mergers could significantly cut down on uncertainty in cosmological parameters. However, binary black hole mergers — the most common gravitational wave event so far — require a different approach.

There currently aren’t any known electromagnetic counterparts to black hole mergers. But if you know roughly where a merger took place and map out all the galaxies in that region, you can generate the probability that the merger took place in a particular galaxy. From there, you can determine the galaxy’s redshift and pair it with the distance as measured from the merger signal.

The more merging events we can detect, the better we can constrain the Hubble Constant, and therefore the age of the universe. According to this figure, we should have a well constrained value by *2023.* pic.twitter.com/B0o7NpYnTm

— astrobites (@astrobites) January 12, 2021

Soares-Santos closed by noting that this particular area of astronomy is changing at a breakneck pace (and would make a great entry point for new grad students!). More optical surveys are coming online in the next few years along with a larger gravitational wave observatory network. It’s feasible that by the late 2020s, we’ll have a high precision measurement of the Hubble constant just based on gravitational wave events!

Interview of Marcelle Soares-Santos by Gloria Fonseca Alvarez
Live-tweeting of the session by Abby Waggoner

This week, AAS Nova and Astrobites are attending the virtual American Astronomical Society (AAS) winter meeting.

AAS Nova Editor Susanna Kohler and AAS Media Fellow Tarini Konchady will join Astrobites Media Intern Haley Wahl and Astrobiters Ellis Avallone, Mike Foley, Michael Hammer, Gourav Khullar, Briley Lewis, Abygail Waggoner, John Weaver, and Luna Zagorac to live-blog the meeting for all those who aren’t attending or can’t make all the sessions they’d like. We plan to cover all of the plenaries and press conferences as well as a number of additional sessions, so follow along here on aasnova.org or on astrobites.org!

As with the summer meeting, we’re sad not to get to talk to you in person, but we’re glad to have this virtual alternative! We look forward to seeing you in sessions and visiting your posters throughout the next three days.

Where can you find us? We’ll be at the Astrobites booth in the Grad Student Fair all week — stop by and join us in the chat room! In addition, you can catch Susanna, Tarini, and Haley at the press conferences all week.

Also, there’s a lot of Astrobiter science at AAS 237 — be sure to check out the talks and posters given by Astrobites authors in the schedule below.

Lastly, if you’re interested in reading up on some of the keynote speakers before their talks at the meeting, be sure to check out the interviews conducted by Astrobites authors! They’ll be published throughout this week, and they provide a great opportunity to discover more about these prominent astrophysicists and learn about the paths they took to where they are today.

You can read the currently published AAS237 keynote speaker interviews here. Be sure to check back all week as the remainder are released!