Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Distinguishing Dark Matter from Modified Gravity   Dynamical mass discrepancies in galaxies have two possible explanations: the
existence of large amounts of dark matter or the breakdown of Newtonian
gravity. True dark matter halos of galaxies could differ in several respects
from apparent halos inferred from misinterpreted modified gravity, and we
discuss two observational tests to probe these differences. Modified gravity
gives generic, geometrical predictions for the shapes of apparent halos, and
also requires that the inferred excess mass strongly correlates with the
visible baryonic mass. Thus modified gravity is more easily falsified, but we
find both hypotheses to be consistent with the meager data on galaxy and
cluster halos; dark matter is not required by current data. We strongly
encourage the acquisition of more data, which could ultimately eliminate one or
other of these possibilities.

27
The categories of this paper are: comp-gas
30
The categories of this paper are: q-alg
4
The categories of this paper are: cond-mat
21
The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
2
The categories of this paper are: math
28
The categories of this paper are: alg-geom
32
The categories of this paper are: atom-ph
17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
16
The categories of this paper are: stat
10
The categories of this paper are: q-bio
0
The categories of this paper are: hep-ph
37
The categories of this paper are: supr-con