The Impact of Bars on Disk Breaks as Probed by S4G Imaging

Muñoz-Mateos, Juan Carlos; Sheth, Kartik; Gil de Paz, Armando; Meidt, Sharon; Athanassoula, E.; Bosma, Albert; Comerón, Sébastien; Elmegreen, Debra M.; Elmegreen, Bruce G.; Erroz-Ferrer, S.; Gadotti, Dimitri A.; Hinz, Joannah L.; Ho, Luis C.; Holwerda, Benne; Jarrett, Thomas H.; Kim, Taehyun; Knapen, J. H.; Laine, Jarkko; Laurikainen, Eija; Madore, Barry F.; Menendez-Delmestre, Karin; Mizusawa, Trisha; Regan, Michael; Salo, Heikki; Schinnerer, Eva; Seibert, Mark; Skibba, Ramin; Zaritsky, Dennis
Bibliographical reference

The Astrophysical Journal, Volume 771, Issue 1, article id. 59, 30 pp. (2013).

Advertised on:
7
2013
Number of authors
28
IAC number of authors
2
Citations
109
Refereed citations
103
Description
We have analyzed the radial distribution of old stars in a sample of 218 nearby face-on disks, using deep 3.6 μm images from the Spitzer Survey of Stellar Structure in Galaxies. In particular, we have studied the structural properties of those disks with a broken or down-bending profile. We find that, on average, disks with a genuine single-exponential profile have a scale length and a central surface brightness which are intermediate to those of the inner and outer components of a down-bending disk with the same total stellar mass. In the particular case of barred galaxies, the ratio between the break and the bar radii (R br/R bar) depends strongly on the total stellar mass of the galaxy. For galaxies more massive than 1010 M ☉, the distribution is bimodal, peaking at R br/R bar ~ 2 and ~3.5. The first peak, which is the most populated one, is linked to the outer Lindblad resonance of the bar, whereas the second one is consistent with a dynamical coupling between the bar and the spiral pattern. For galaxies below 1010 M ☉, breaks are found up to ~10 R bar, but we show that they could still be caused by resonances given the rising nature of rotation curves in these low-mass disks. While not ruling out star formation thresholds, our results imply that radial stellar migration induced by non-axisymmetric features can be responsible not only for those breaks at ~2 R bar, but also for many of those found at larger radii.
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