TY - JOUR
T1 - Outer-disk populations in NGC 7793
T2 - evidence for stellar radial migration
AU - Radburn-Smith, David J.
AU - Roškar, Rok
AU - Debattista, Victor P.
AU - Dalcanton, Julianne J.
AU - Streich, David
AU - De Jong, Roelof S.
AU - Vlajić, Marija
AU - Holwerda, Benne W.
AU - Purcell, Chris W.
AU - Dolphin, Andrew E.
AU - Zucker, Daniel B.
PY - 2012/7/10
Y1 - 2012/7/10
N2 - We analyzed the radial surface brightness profile of the spiral galaxy NGC7793 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″ (5.1kpc). 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 NGC7793 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.
AB - We analyzed the radial surface brightness profile of the spiral galaxy NGC7793 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″ (5.1kpc). 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 NGC7793 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.
UR - http://www.scopus.com/inward/record.url?scp=84863110104&partnerID=8YFLogxK
U2 - 10.1088/0004-637X/753/2/138
DO - 10.1088/0004-637X/753/2/138
M3 - Article
AN - SCOPUS:84863110104
SN - 0004-637X
VL - 753
SP - 1
EP - 8
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 138
ER -