We present the 2020 version of the Siena Galaxy Atlas (SGA-2020), a multi-wavelength optical and infrared imaging atlas of 383,620 nearby galaxies. The SGA-2020 uses optical grz imaging over ≈20,000 deg2 from the DESI Legacy Imaging Surveys Data Release 9 and infrared imaging in four bands (spanning 3.4-22 μm) from the six-year unWISE coadds; it is more than 95% complete for galaxies larger than R(26)≈25 arcsec and r<18 measured at the 26 mag arcsec−2 isophote in the r-band. The atlas delivers precise coordinates, multi-wavelength mosaics, azimuthally averaged optical surface brightness profiles, model images and photometry, and additional ancillary metadata for the full sample. Coupled with existing and forthcoming optical spectroscopy from the Dark Energy Spectroscopic Instrument (DESI), the SGA-2020 will facilitate new detailed studies of the star formation and mass assembly histories of nearby galaxies; enable precise measurements of the local velocity field via the Tully-Fisher and Fundamental Plane relations; serve as a reference sample of lasting legacy value for time-domain and multi-messenger astronomical events; and more.
@article{arxiv.2307.04888,
title = {Siena Galaxy Atlas 2020},
author = {John Moustakas and Dustin Lang and Arjun Dey and Stéphanie Juneau and Aaron Meisner and Adam D. Myers and Edward F. Schlafly and David J. Schlegel and Francisco Valdes and Benjamin A. Weaver and Rongpu Zhou},
journal= {arXiv preprint arXiv:2307.04888},
year = {2023}
}
Comments
47 pages, 13 figures, 5 tables; submitted to ApJS. All catalogs and data are publicly available through the SGA web-portal at https://sga.legacysurvey.org