Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Wolf-Rayet Galaxies in the Sloan Digital Sky Survey: the metallicity
  dependence of the initial mass function   We use a large sample of 174 Wolf-Rayet (WR) galaxies drawn from the Sloan
Digital Sky Survey to study whether and how the slope of the stellar initial
mass function depends on metallicity. We calculate for each object its oxygen
abundance according to which we divide our sample into four metallicity
subsamples. For each subsample, we then measure three quantities: the
equivalent width of \hb emission line, the equivalent width of WR bump around
4650\AA, and the WR bump-to-\hb intensity ratio, and compare to the predictions
of the same quantities by evolutionary synthesis models of Schaerer & Vacca.
Such comparisons lead to a clear dependence of the slope of initial mass
function ($\alpha$) on metallicity in that galaxies at higher metallicities
tend to have steeper initial mass functions, with the slope index ranging from
$\alpha\sim$1.00 for the lowest metallicity of $Z=0.001$ to $\alpha\sim$3.30
for the highest metallicity $Z=0.02$. We have carefully examined the possible
sources of systematic error either in models or in our observational
measurements and shown that these sources do not change this result.

2
The categories of this paper are: math
13
The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
31
The categories of this paper are: ao-sci
1
The categories of this paper are: cs
33
The categories of this paper are: plasm-ph
23
The categories of this paper are: solv-int
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
21
The categories of this paper are: adap-org
25
The categories of this paper are: patt-sol
26
The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics