Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: First detection of CS masers around a high-mass young stellar object,
  W51 e2e   We report the discovery of maser emission in the two lowest rotational
transitions of CS toward the high-mass protostar W51 e2e with ALMA and the
JVLA. The masers from CS J=1-0 and J=2-1 are neither spatially nor spectrally
coincident (they are separated by ~150 AU and ~30 km/s), but both appear to
come from the base of the blueshifted outflow from this source. These CS masers
join a growing list of rarely-detected maser transitions that may trace a
unique phase in the formation of high-mass protostars.

20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
26
The categories of this paper are: bayes-an
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas
35
The categories of this paper are: mtrl-th
0
The categories of this paper are: hep-ph
23
The categories of this paper are: solv-int
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex