RT Journal Article
T1 Reconstructing the stellar mass distributions of galaxies using S^4G irac 3.6 and 4.5 μm images. II. The conversion from light to mass
A1 Meidt, Sharon E.
A1 Schinnerer, Eva
A1 Van de Ven, Glenn
A1 Zaritsky, Dennis
A1 Peletier, Reynier
A1 Knapen, Johan H.
A1 Sheth, Kartik
A1 Regan, Michael W.
A1 Querejeta, Miguel
A1 Muñoz Mateos, Juan Carlos
A1 Kim, Taehyun
A1 Hinz, Joannah L.
A1 Gil De Paz, Armando
A1 Athanassoula, E.
A1 Bosma, Albert
A1 Buta, Ronald J.
A1 Cisternas, Mauricio
A1 Ho, Luis C.
A1 Holwerda, Benne W.
A1 Skibba, Ramin
A1 Laurikainen, Eija
A1 Salo, Heikki
A1 Gadotti, Dimitri A.
A1 Laine, Jarkko
A1 Erroz Ferrer, Santiago
A1 Comerón, Sébastien
A1 Menéndez-Delmestre, Karín
A1 Seibert, Mark
A1 Mizusawa, Trisha
AB We present a new approach for estimating the 3.6 μm stellar mass-to-light (M/L) ratio Υ_3.6 in terms of the [3.6]-[4.5] colors of old stellar populations. Our approach avoids several of the largest sources of uncertainty in existing techniques using population synthesis models. By focusing on mid-IR wavelengths, we gain a virtually dust extinction-free tracer of the old stars, avoiding the need to adopt a dust model to correctly interpret optical or optical/near-IR colors normally leveraged to assign the mass-to-light ratio Upsilon. By calibrating a new relation between near-IR and mid-IR colors of giant stars observed in GLIMPSE we also avoid the discrepancies in model predictions for the [3.6]-[4.5] colors of old stellar populations due to uncertainties in the molecular line opacities assumed in template spectra. We find that the [3.6]-[4.5] color, which is driven primarily by metallicity, provides a tight constraint on Upsilon3.6, which varies intrinsically less than at optical wavelengths. The uncertainty on Υ3.6 of ~0.07 dex due to unconstrained age variations marks a significant improvement on existing techniques for estimating the stellar M/L with shorter wavelength data. A single Υ3.6 = 0.6 (assuming a Chabrier initial mass function (IMF)), independent of [3.6]-[4.5] color, is also feasible because it can be applied simultaneously to old, metal-rich and young, metal-poor populations, and still with comparable (or better) accuracy (~0.1 dex) than alternatives. We expect our Υ3.6 to be optimal for mapping the stellar mass distributions in S4G galaxies, for which we have developed an independent component analysis technique to first isolate the old stellar light at 3.6 μm from nonstellar emission (e.g., hot dust and the 3.3 polycyclic aromatic hydrocarbon feature). Our estimate can also be used to determine the fractional contribution of nonstellar emission to global (rest-frame) 3.6 μm fluxes, e.g., in WISE imaging, and establishes a reliable basis for exploring variations in the stellar IMF.
PB American Astronomical Society
SN 0004-637X
YR 2014
FD 2014-06-20
LK https://hdl.handle.net/20.500.14352/34981
UL https://hdl.handle.net/20.500.14352/34981
LA eng
NO DAGAL network of the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme
NO National Radio Astronomy Observatory (NRAO)
NO Unión Europea (UE)
NO 7th Framework Programme 7FP (UE)
DS Docta Complutense
RD 4 abr 2025