These three galaxies (click for a full view!) were imaged as a part of the Spitzer Survey of Stellar Structure in Galaxies (S4G), a recent survey of 2352 nearby galaxies with deep imaging at 3.6 and 4.5 μm. The bottom panels show false-color near-UV and far-UV images previously obtained with GALEX. The top panels show the new images obtained with Spitzer as part of S4G. The three galaxies shown here represent three types of galaxies that have a high concentration of mass in their centers, yet still have a high specific star-formation rate (the star formation rate per unit stellar mass):
- Barred galaxies with a prominent ring around their nucleus, like NGC 7552
- Interacting systems, like NGC 2782
- Galaxies with compact bulges and smooth extended disks, like NGC 3642
To learn why this is the case, and to see more results from S4G, see the original paper below.
Citation
Juan Carlos Muñoz-Mateos et al 2015 ApJS 219 3. doi:10.1088/0067-0049/219/1/3