Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: What aspects of galaxy environment matter?   We determine what aspects of the density field surrounding galaxies most
affect their properties. For Sloan Digital Sky Survey galaxies, we measure the
group environment, meaning the host group luminosity and the distance from the
group center (hereafter, ``groupocentric distance''). For comparison, we
measure the surrounding density field on scales ranging from 100 kpc/h to 10
Mpc/h. We use the relationship between color and group environment to test the
null hypothesis that only the group environment matters, searching for a
residual dependence of properties on the surrounding density. Generally, red
galaxies are slightly more clustered on small scales (about 100--300 kpc/h)
than the null hypothesis predicts, possibly indicating that substructure within
groups has some importance. At large scales (> 1 Mpc/h), the actual projected
correlation functions of galaxies are biased at less than the 5% level with
respect to the null hypothesis predictions. We exclude strongly the converse
null hypothesis, that only the surrounding density (on any scale) matters.
These results generally encourage the use of the halo model description of
galaxy bias, which models the galaxy distribution as a function of host halo
mass alone. We compare these results to proposed galaxy formation scenarios
within the Cold Dark Matter cosmological model.

35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
16
The categories of this paper are: stat
19
The categories of this paper are: eess
34
The categories of this paper are: chem-ph
0
The categories of this paper are: hep-ph
3
The categories of this paper are: physics
28
The categories of this paper are: alg-geom
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The categories of this paper are: atom-ph
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The categories of this paper are: supr-con
7
The categories of this paper are: hep-th