Physics and Astronomy
We have analyzed the radial distribution of old stars in a sample of 218 nearby face-on disks, using deep 3.6μm 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 (Rbr/Rbar) depends strongly on the total stellar mass of the galaxy. For galaxies more massive than 1010 M, the distribution is bimodal, peaking at Rbr/Rbar ∼ 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 Rbar, 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 Rbar, but also for many of those found at larger radii.
Original Publication Information
Munoz-Mateos, Juan Carlos, et al. "The Impact of Bars on Disk Breaks as Probed by S4G Imaging." 2013. The Astrophysical Journal 771(1): 30 pp.
Munoz-Mateos, Juan Carlos; Sheth, Kartik; Gil de Paz, Armando; Meidt, Sharon; Athanassoula, E.; Bosma, Albert; Comeron, Sebastien; Elmegreen, Debra M.; Elmegreen, Bruce G.; Erroz-Ferrer, Santiago; Gadotti, Dimitri A.; Hinz, Joannah L.; Ho, Luis C.; Holwerda, Benne W.; Jarrett, Thomas H.; Kim, Taehyun; Knapen, Johan H.; Laine, Jarkko; Laurikainen, Eija; Madore, Barry F.; Menendez-Delmestre, Karin; Mizusawa, Trisha; Regan, Michael; Salo, Heikki; Schinnerer, Eva; Seibert, Mark; Skibba, Ramin; and Zaritsky, Dennis, "The impact of bars on disk breaks as probed by S4G imaging." (2013). Faculty Scholarship. 225.