Outer-disk populations in NGC 7793

evidence for stellar radial migration

David J. Radburn-Smith*, Rok Roškar, Victor P. Debattista, Julianne J. Dalcanton, David Streich, Roelof S. De Jong, Marija Vlajić, Benne W. Holwerda, Chris W. Purcell, Andrew E. Dolphin, Daniel B. Zucker

*Corresponding author for this work

Research output: Contribution to journalArticle

52 Citations (Scopus)


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.

Original languageEnglish
Article number138
Pages (from-to)1-8
Number of pages8
JournalAstrophysical Journal
Issue number2
Publication statusPublished - 10 Jul 2012

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    Radburn-Smith, D. J., Roškar, R., Debattista, V. P., Dalcanton, J. J., Streich, D., De Jong, R. S., ... Zucker, D. B. (2012). Outer-disk populations in NGC 7793: evidence for stellar radial migration. Astrophysical Journal, 753(2), 1-8. [138]. https://doi.org/10.1088/0004-637X/753/2/138