Sjoert van Velzen et al 2021 ApJ 908 4
17 new tidal disruption events (TDEs) have been detected by the Zwicky Transient Facility and followed up with Swift UV and X-ray observations, allowing homogeneous analysis of a total sample of ~30 TDE light curves.
Adam G. Riess et al 2021 ApJL 908 L6
Recalibration of the extragalactic distance ladder using new observations of 75 Milky Way Cepheids results in a measured Hubble-constant value in 4.2σ tension with the prediction from Planck CMB observations under ΛCDM.
T. J. Davidge 2021 AJ 161 93
The nearby late-type spiral galaxy NGC 247 displays a number of morphologies consistent with a significantly lop-sided spiral galaxy, pointing to likely past interactions with its nearby starburst galaxy companion NGC 253.
Ryunosuke Maeda et al 2021 ApJ 908 2
New simulations demonstrate that the precursors of young massive clusters are formed by the global gravitational collapse of molecular clouds, and young massive clusters can be formed even in low-metallicity environments.
Michael J. Koss et al 2021 ApJS 252 29
A new study of host-galaxy molecular gas properties suggests that active galactic nuclei in massive galaxies tend to have more molecular gas and higher gas fractions than inactive galaxies matched in stellar mass.
A. Albert et al 2021 ApJL 907 L30
The HAWC observatory has discovered the γ-ray source HAWC J1825-134, whose energy spectrum extends well beyond 200 TeV; the source of the radiation is likely PeV cosmic rays colliding with ambient gas.