The Herschel Exploitation Of Local Galaxy Andromeda (HELGA). II. Dust And Gas In Andromeda
MetadataShow full item record
We present an analysis of the dust and gas in Andromeda, using Herschel images sampling the entire far-infrared peak. We fit a modified-blackbody model to similar to 4000 quasi-independent pixels with spatial resolution of similar to 140 pc and find that a variable dust-emissivity index (beta) is required to fit the data. We find no significant long-wavelength excess above this model, suggesting there is no cold dust component. We show that the gas-to-dust ratio varies radially, increasing from similar to 20 in the center to similar to 70 in the star-forming ring at 10 kpc, consistent with the metallicity gradient. In the 10 kpc ring the average beta is similar to 1.9, in good agreement with values determined for the Milky Way (MW). However, in contrast to the MW, we find significant radial variations in beta, which increases from 1.9 at 10 kpc to similar to 2.5 at a radius of 3.1 kpc and then decreases to 1.7 in the center. The dust temperature is fairly constant in the 10 kpc ring (ranging from 17 to 20 K), but increases strongly in the bulge to similar to 30 K. Within 3.1 kpc we find the dust temperature is highly correlated with the 3.6 mu m flux, suggesting the general stellar population in the bulge is the dominant source of dust heating there. At larger radii, there is a weak correlation between the star formation rate and dust temperature. We find no evidence for "dark gas" in M31 in contrast to recent results for the MW. Finally, we obtained an estimate of the CO X-factor by minimizing the dispersion in the gas-to-dust ratio, obtaining a value of (1.9 +/- 0.4) x 10(20) cm(-2) [K km s(-1)](-1).
CitationSmith, Matthew William L., Stephen Anthony Eales, Haley Louise Gomez, J. Roman-Duval, Jacopo Fritz, R. Braun, Maarten Baes et al. "The Herschel Exploitation of Local Galaxy Andromeda (HELGA). II. Dust and Gas in Andromeda." The Astrophysical Journal, Vol. 756, No. 1 (Sep., 2012): 40.
Showing items related by title, author, creator and subject.
Papovich, Casey; Bassett, Robert; Lotz, Jennifer M.; van der Wel, A.; Tran, K. V.; Finkelstein, Steven L.; Bell, Eric F.; Conselice, Christopher J.; Dekel, Avishai; Dunlop, J. S.; Guo, Y. C.; Faber, S. M.; Farrah, D.; Ferguson, Henry C.; Finkelstein, Keely D.; Haussler, Boris; Kocevski, D. D.; Koekemoer, A. M.; Koo, D. C.; McGrath, E. J.; McLure, R. J.; McIntosh, Daniel H.; Momcheva, I.; Newman, Jeffrey A.; Rudnick, Gregory; Weiner, B.; Willmer, Christopher N. A.; Wuyts, S. (2012-05)We discuss the structural and morphological properties of galaxies in a z = 1.62 proto-cluster using near-IR imaging data from Hubble Space Telescope Wide Field Camera 3 data of the Cosmic Assembly Near-IR Deep Extragalactic ...
The Structure Of Classical Bulges And Pseudobulges: The Link Between Pseudobulges And Sersic Index Fisher, David B.; Drory, Niv (2008-08)In this paper, we study the properties of pseudobulges (bulges that appear similar to disk galaxies) and classical bulges (bulges which appear similar to E-type galaxies) in bulge-disk decompositions. We show that the ...
Konstantopoulos, I. S.; Gallagher, S. C.; Fedotov, K.; Durrell, P. R.; Heiderman, Amanda; Elmegreen, D. M.; Charlton, J. C.; Hibbard, J. E.; Tzanavaris, P.; Chandar, R.; Johnson, K. E.; Maybhate, A.; Zabludoff, A. E.; Gronwall, Caryl; Szathmary, D.; Hornschemeier, Ann E.; English, J.; Whitmore, B.; de Oliveira, C. M.; Mulchaey, J. S. (2010-11)The environment where galaxies are found heavily influences their evolution. Close groupings, like the ones in the cores of galaxy clusters or compact groups, evolve in ways far more dramatic than their isolated counterparts. ...