Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: HIghMass - High HI Mass, HI-rich Galaxies at z~0: High-Resolution VLA
  Imaging of UGC 9037 and UGC 12506   We present resolved HI observations of two galaxies, UGC 9037 and UGC 12506,
members of a rare subset of galaxies detected by the ALFALFA extragalactic HI
survey characterized by high HI mass and high gas fraction for their stellar
masses. Both of these galaxies have M$_*>10^{10}$ M$_\odot$ and M$_\text{HI}>$
M$_*$, as well as typical star formation rates for their stellar masses. How
can such galaxies have avoided consuming their massive gas reservoirs? From gas
kinematics, stability, star formation, and dark matter distributions of the two
galaxies, we infer two radically different histories. UGC 9037 has high central
HI surface density ($>10$ M$_\odot$ pc$^{-2}$). Its gas at most radii appears
to be marginally unstable with non-circular flows across the disk. These
properties are consistent with UGC 9037 having recently acquired its gas and
that it will soon undergo major star formation. UGC 12506 has low surface
densities of HI, and its gas is stable over most of the disk. We predict its
gas to be HI-dominated at all except the smallest radii. We claim a very high
dark matter halo spin parameter for UGC 12506 ($\lambda=0.15$), suggesting that
its gas is older, and has never undergone a period of star formation
significant enough to consume the bulk of its gas.

5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
34
The categories of this paper are: chem-ph
36
The categories of this paper are: cmp-lg
7
The categories of this paper are: hep-th
16
The categories of this paper are: stat
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
11
The categories of this paper are: hep-lat
32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex