Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Being WISE I: Validating Stellar Population Models and M/L ratios at 3.4
  and 4.6 microns   Using data from the WISE mission, we have measured near infra-red (NIR)
photometry of a diverse sample of dust-free stellar systems (globular clusters,
dwarf and giant early-type galaxies) which have metallicities that span the
range -2.2 < [Fe/H] (dex) < 0.3. This dramatically increases the sample size
and broadens the metallicity regime over which the 3.4 (W1) and 4.6 micron (W2)
photometry of stellar populations have been examined.
  We find that the W1 - W2 colors of intermediate and old (> 2 Gyr) stellar
populations are insensitive to the age of the stellar population, but that the
W1 - W2 colors become bluer with increasing metallicity, a trend not well
reproduced by most stellar population synthesis (SPS) models. In common with
previous studies, we attribute this behavior to the increasing strength of the
CO absorption feature located in the 4.6 micron bandpass with metallicity.
  Having used our sample to validate the efficacy of some of the SPS models, we
use these models to derive stellar mass-to-light ratios in the W1 and W2 bands.
Utilizing observational data from the SAURON and ATLAS3D surveys, we
demonstrate that these bands provide extremely simple, yet robust stellar mass
tracers for dust free older stellar populations that are freed from many of the
uncertainties common among optical estimators.

18
The categories of this paper are: econ
3
The categories of this paper are: physics
10
The categories of this paper are: q-bio
25
The categories of this paper are: patt-sol
7
The categories of this paper are: hep-th
11
The categories of this paper are: hep-lat
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
2
The categories of this paper are: math
16
The categories of this paper are: stat
24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th
33
The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph
4
The categories of this paper are: cond-mat