OUTER-DISK POPULATIONS IN NGC 7793: EVIDENCE FOR STELLAR RADIAL MIGRATION

Journal Article · Tue Jul 10 04:00:00 EDT 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/753/2/138· OSTI ID:22039384

Radburn-Smith, David J; Dalcanton, Julianne J ^[1]; Roskar, Rok ^[2]; Debattista, Victor P ^[3]; Streich, David; De Jong, Roelof S; Vlajic, Marija ^[4]; Holwerda, Benne W ^[5]; Purcell, Chris W ^[6]; Dolphin, Andrew E ^[7]; Zucker, Daniel B ^[8]

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1. Department of Astronomy, University of Washington, Seattle, WA 98195 (United States)
2. Institut fuer Theoretische Physik, Universitaet Zuerich (Switzerland)
3. Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE (United Kingdom)
4. Leibniz-Institut fuer Astrophysik Potsdam, D-14482 Potsdam (Germany)
5. European Space Agency, ESTEC, 2200 AG Noordwijk (Netherlands)
6. Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260 (United States)
7. Raytheon, 1151 E. Hermans Road, Tucson, AZ 85756 (United States)
8. Department of Physics and Astronomy, Macquarie University, NSW 2109 (Australia)

We analyzed the radial surface brightness profile of the spiral galaxy NGC 7793 using HST/ACS images from the GHOSTS survey and a new HST/WFC3 image across the disk break. We used the photometry of resolved stars to select distinct populations covering a wide range of stellar ages. We found breaks in the radial profiles of all stellar populations at 280'' ({approx}5.1 kpc). Beyond this disk break, the profiles become steeper for younger populations. This same trend is seen in numerical simulations where the outer disk is formed almost entirely by radial migration. We also found that the older stars of NGC 7793 extend significantly farther than the underlying H I disk. They are thus unlikely to have formed entirely at their current radii, unless the gas disk was substantially larger in the past. These observations thus provide evidence for substantial stellar radial migration in late-type disks.

• OSTI ID: 22039384
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 753; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASTRONOMY
ASTROPHYSICS
BRIGHTNESS
COMPUTERIZED SIMULATION
GALAXIES
IMAGES
PHOTOMETRY
STARS
SURFACES