期刊
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
卷 507, 期 2, 页码 2488-2499出版社
OXFORD UNIV PRESS
DOI: 10.1093/mnras/stab2341
关键词
galaxies: elliptical and lenticular, cD; galaxies: evolution; galaxies: formation; galaxies: fundamental parameters; galaxies: spiral; galaxies: star formation
资金
- Beijing Municipal Natural Science Foundation [1204038]
- National Key Research and Development Program of China [2018YFA0404501]
- National Natural Science Foundation of China (NSFC) [11903046, U1931110, 11333003, 11761131004, 11390372]
- National Key Program for Science and Technology Research and Development [2016YFA0400704]
- National Science Foundation [AST-1715898]
- Alfred P. Sloan Foundation
- U.S. Department of Energy Office of Science
- Brazilian Participation Group
- Carnegie Institution for Science
- Carnegie Mellon University
- Center for Astrophysics | Harvard Smithsonian
- Chilean Participation Group
- French Participation Group
- Instituto de Astrof'isica de Canarias
- Johns Hopkins University
- Kavli Institute for the Physics and Mathematics of the Universe (IPMU) / University of Tokyo
- Korean Participation Group
- Lawrence Berkeley National Laboratory
- Leibniz Institut fur Astrophysik Potsdam (AIP)
- Max-Planck-Institut fur Astronomie (MPIA Heidelberg)
- Max-Planck-Institut fur Astrophysik (MPA Garching)
- Max-Planck-Institut fur Extraterrestrische Physik (MPE)
- National Astronomical Observatories of China
- New Mexico State University
- New York University
- University of Notre Dame
- Observat'ario Nacional / MCTI
- Ohio State University
- Pennsylvania State University
- Shanghai Astronomical Observatory
- United Kingdom Participation Group
- Universidad Nacional Aut 'onoma de M'exico
- University of Arizona
- University of Colorado Boulder
- University of Oxford
- University of Portsmouth
- University of Utah
- University of Virginia
- University of Washington
- University of Wisconsin
- Vanderbilt University
- Yale University
The study reveals that the gradient of stellar mass-to-light ratio varies with galaxy mass and is heavily influenced by stellar age. Galaxies with higher specific star formation rates show steeper negative del(M-*/L-r) gradients.
The stellar mass-to-light ratio gradient in SDSS r-band del(M-*/L-r) of a galaxy depends on its mass assembly history, which is imprinted in its morphology and gradients of age, metallicity, and stellar initial mass function (IMF). Taking a MaNGA sample of 2051 galaxies with stellar masses ranging from 10(9) to 10(12)M(circle dot) released in SDSS DR15, we focus on face-on galaxies, without merger and bar signatures, and investigate the dependence of the 2D del(M-*/L-r) on other galaxy properties, including M-*/L-r-colour relationships by assuming a fixed Salpeter IMF as the mass normalization reference. The median gradient is del M-*/L-r similar to -0.1 (i.e. the M-*/L-r is larger at the centre) for massive galaxies, becomes flat around M-* similar to 10(10)M(circle dot) and change sign to del M-*/L-r similar to 0.1 at the lowest masses. The M-*/L-r inside a half-light radius increases with increasing galaxy stellar mass; in each mass bin, early-type galaxies have the highest value, while pure-disc late-type galaxies have the smallest. Correlation analyses suggest that the mass-weighted stellar age is the dominant parameter influencing the M-*/L-r profile, since a luminosity-weighted age is easily affected by star formation when the specific star formation rate (sSFR) inside the half-light radius is higher than 10(-3)Gyr(-1). With increased sSFR gradient, one can obtain a steeper negative del(M-*/L-r). The scatter in the slopes of M-*/L-colour relations increases with increasing sSFR, for example, the slope for post-starburst galaxies can be flattened to 0.45 from the global value 0.87 in the M-*/L versus g - r diagram. Hence converting galaxy colours to M-*/L should be done carefully, especially for those galaxies with young luminosity-weighted stellar ages, which can have quite different star formation histories.
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