Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: W51 IRS 2: A Massive Jet Emerging from a Molecular Cloud into an H II
  Region   We have mapped [Ne II] (12.8um) and [S IV] (10.5um) emission from W51 IRS 2
with TEXES on Gemini North, and we compare these data to VLA free-free
observations and VLT near-infrared images. With 0.5" spatial and 4 km/s
spectral resolution we are able to separate the ionized gas into several
components: an extended H II region on the front surface of the molecular
cloud, several embedded compact H II regions, and a streamer of high velocity
gas. We interpret the high velocity streamer as a precessing or fan-like jet,
which has emerged from the molecular cloud into an OB star cluster where it is
being ionized.

0
The categories of this paper are: hep-ph
15
The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph
33
The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th
18
The categories of this paper are: econ
27
The categories of this paper are: comp-gas
4
The categories of this paper are: cond-mat
25
The categories of this paper are: patt-sol
32
The categories of this paper are: atom-ph
7
The categories of this paper are: hep-th
20
The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
26
The categories of this paper are: bayes-an