Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Low-surface-density galaxies and the modified dynamics   Very-low-surface-density galactic systems have very low mean accelerations.
They thus provide quintessential tests of the Modified Dynamics (MOND), which
predicts an increasing mass discrepancy with decreasing acceleration. We
describe succinctly the results pertinent to several classes of such objects:
Low-luminosity (dwarf) spirals, irregular dwarf spirals, normal-lumonosity-but
-low-surface-density spirals, and dwarf-spheroidal satellites of the Milky Way.

20
The categories of this paper are: acc-phys
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics
2
The categories of this paper are: math
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
0
The categories of this paper are: hep-ph
16
The categories of this paper are: stat