Bibcode
Querejeta, M.; Meidt, Sharon E.; Schinnerer, Eva; Cisternas, M.; Muñoz-Mateos, Juan Carlos; Sheth, Kartik; Knapen, J. H.; van de Ven, Glenn; Norris, Mark A.; Peletier, Reynier; Laurikainen, Eija; Salo, Heikki; Holwerda, Benne W.; Athanassoula, E.; Bosma, Albert; Groves, Brent; Ho, Luis C.; Gadotti, Dimitri A.; Zaritsky, Dennis; Regan, Michael; Hinz, Joannah; Gil de Paz, Armando; Menendez-Delmestre, Karin; Seibert, Mark; Mizusawa, Trisha; Kim, Taehyun; Erroz-Ferrer, S.; Laine, Jarkko; Comerón, Sébastien
Bibliographical reference
The Astrophysical Journal Supplement Series, Volume 219, Issue 1, article id. 5, 19 pp. (2015).
Advertised on:
7
2015
Citations
206
Refereed citations
194
Description
The mid-infrared is an optimal window to trace stellar mass in nearby
galaxies and the 3.6 μ {{m}} 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 (S4G). This
survey consists of images in two infrared bands (3.6 and 4.5 μ
{{m}}), 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 μ {{m}} flux. We exclude from our ICA analysis galaxies with low
signal-to-noise ratio ({{S}}/{{N}}\lt 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 μ {{m}} 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}({\text{}}M/L) = -0.339(+/- 0.057) ×
([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.
Related projects
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Our small group is well known and respected internationally for our innovative and important work on various aspects of the structure and evolution of nearby spiral galaxies. We primarily use observations at various wavelengths, exploiting synergies that allow us to answer the most pertinent questions relating to what the main properties of
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