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Outer-disk populations in NGC 7793: evidence for stellar radial migration


Radburn-Smith, David J; Roškar, Rok; Debattista, Victor P; Dalcanton, Julianne J; Streich, David; de Jong, Roelof S; Vlajić, Marija; Holwerda, Benne W; Purcell, Chris W; Dolphin, Andrew E; Zucker, Daniel B (2012). Outer-disk populations in NGC 7793: evidence for stellar radial migration. Astrophysical Journal, 753(2):138.

Abstract

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'' (~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.

Abstract

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'' (~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.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Institute for Computational Science
Dewey Decimal Classification:530 Physics
Language:English
Date:June 2012
Deposited On:23 Jan 2013 14:51
Last Modified:07 Dec 2017 18:37
Publisher:IOP Publishing
ISSN:0004-637X
Publisher DOI:https://doi.org/10.1088/0004-637X/753/2/138

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