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The SPITZER survey of stellar structure in galaxies (S(^4)G): precise stellar mass distributions from automated dust correction at 3.6 μm



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Gil de Paz, Armando and otros, ... (2015) The SPITZER survey of stellar structure in galaxies (S(^4)G): precise stellar mass distributions from automated dust correction at 3.6 μm. Astrophysical journal supplement series, 219 (1). ISSN 0067-0049


Official URL: http://dx.doi.org/10.1088/0067-0049/219/1/5



The mid-infrared is an optimal window to trace stellar mass in nearby galaxies and the 3.6 μm IRAC band has been exploited to this effect, but such mass estimates can be biased by dust emission. We present our pipeline to reveal the old stellar flux at 3.6 μm and obtain stellar mass maps for more than 1600 galaxies available from the Spitzer Survey of Stellar Structure in Galaxies (S^4G). This survey consists of images in two infrared bands (3.6 and 4.5 μm), and we use the Independent Component Analysis (ICA) method presented in Meidt et al. to separate the dominant light from old stars and the dust emission that can significantly contribute to the observed 3.6 μm flux. We exclude from our ICA analysis galaxies with low signal-to-noise ratio (S/N < 10) and those with original [3.6]-[4.5] colors compatible with an old stellar population, indicative of little dust emission (mostly early Hubble types, which can directly provide good mass maps). For the remaining 1251 galaxies to which ICA was successfully applied, we find that as much as 10%-30% of the total light at 3.6 μm typically originates from dust, and locally it can reach even higher values. This contamination fraction shows a correlation with specific star formation rates, confirming that the dust emission that we detect is related to star formation. Additionally, we have used our large sample of mass estimates to calibrate a relationship of effective mass-to-light ratio (M/L) as a function of observed [3.6]-[4.5] color: log(M/L) = -0.339 (±0.057 x) ([3.6]-[4.5])-0.336 (±0.002). Our final pipeline products have been made public through IRSA, providing the astronomical community with an unprecedentedly large set of stellar mass maps ready to use for scientific applications.

Item Type:Article
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© 2015. The American Astronomical Society. Artículo firmado por 29 autores. We are grateful to the anonymous referee for very insightful comments and suggestions, which have helped us improve the quality of the paper. We acknowledge financial support to the DAGAL network from the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/2007-2013/under REA grant agreement number PITN-GA-2011-289313. M.Q. acknowledges the International Max Planck Research School for Astronomy and Cosmic Physics at the University of Heidelberg (IMPRS-HD). We thank Emer Brady for acting as an external classifier for assigning quality flags, and Simón Díaz García for helpful comments. K.S., J.-C. M.-M., and T.K. acknowledge support from the National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. E.A. and A.B. acknowledge financial support from the CNES (Centre National d'Etudes Spatiales). L.C.H. acknowledges support from the Kavli Foundation, Peking University, and the Chinese Academy of Science through grant No. XDB09030100 (Emergence of Cosmological Structures) from the Strategic Priority Research Program. This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

Uncontrolled Keywords:Infrared array camera; Independent component analysis; Nearby spiral galaxies; Secular evolution; Sauron project; Surface photometry; Space-telescope; Central region; Star-formation; Disk galaxies
Subjects:Sciences > Physics > Astrophysics
Sciences > Physics > Astronomy
ID Code:33281
Deposited On:25 Sep 2015 14:05
Last Modified:10 Dec 2018 15:05

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