THE STRUCTURE AND STELLAR CONTENT OF THE OUTER DISKS OF GALAXIES: A NEW VIEW FROM THE Pan-STARRS1 MEDIUM DEEP SURVEY

Journal Article · Fri Feb 20 04:00:00 EST 2015 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/800/2/120· OSTI ID:22522119

Zheng, Zheng; Thilker, David A.; Heckman, Timothy M. ^[1]; Meurer, Gerhardt R. ^[2]; Burgett, W. S.; Huber, M. E.; Kaiser, N.; Magnier, E. A.; Tonry, J. L.; Wainscoat, R. J.; Waters, C. ^[3]; Chambers, K. C.; Metcalfe, N. ^[4]; Price, P. A. ^[5]

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1. Department of Physics and Astronomy, Johns Hopkins University, 3701 San Martin Drive, Baltimore, MD 21218 (United States)
2. International Center for Radio Astronomy Research, The University of Western Australia, M468, 35 StirlingHighway, Crawley, WA 6009 (Australia)
3. Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States)
4. Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom)
5. Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

We present the results of an analysis of Pan-STARRS1 Medium Deep Survey multi-band (grizy) images of a sample of 698 low-redshift disk galaxies that span broad ranges in stellar mass, star-formation rate, and bulge/disk ratio. We use population synthesis spectral energy distribution fitting techniques to explore the radial distribution of the light, color, surface mass density, mass/light ratio, and age of the stellar populations. We characterize the structure and stellar content of the galaxy disks out to radii of about twice Petrosian r {sub 90}, beyond which the halo light becomes significant. We measure normalized radial profiles for sub-samples of galaxies in three bins each of stellar mass and concentration. We also fit radial profiles to each galaxy. The majority of galaxies have down-bending radial surface brightness profiles in the bluer bands with a break radius at roughly r {sub 90}. However, they typically show single unbroken exponentials in the reddest bands and in the stellar surface mass density. We find that the mass/light ratio and stellar age radial profiles have a characteristic 'U' shape. There is a good correlation between the amplitude of the down-bend in the surface brightness profile and the rate of the increase in the M/L ratio in the outer disk. As we move from late- to early-type galaxies, the amplitude of the down-bend and the radial gradient in M/L both decrease. Our results imply a combination of stellar radial migration and suppression of recent star formation can account for the stellar populations of the outer disk.

• OSTI ID: 22522119
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 800; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
BRIGHTNESS
COLOR
CONCENTRATION RATIO
DENSITY
ENERGY SPECTRA
GALAXIES
IMAGES
MASS
PHOTOMETRY
RED SHIFT
SPATIAL DISTRIBUTION
STAR EVOLUTION
STARS
SURFACES
VISIBLE RADIATION