Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: IRAS 16293-2422: Evidence for Infall onto a Counter-Rotating
  Protostellar Accretion Disk   We report high spatial resolution VLA observations of the low-mass
star-forming region IRAS 16293-2422 using four molecular probes: ethyl cyanide
(CH$_3$CH$_2$CN), methyl formate (CH$_3$OCHO), formic acid (HCOOH), and the
ground vibrational state of silicon monoxide (SiO). Ethyl cyanide emiss ion has
a spatial scale of $\sim20''$ and encompasses binary cores A and B as
determined by continuum emission peaks. Surrounded by formic acid emission,
methyl formate emission has a spatial scale of $\sim6''$and is confined to core
B. SiO emission shows two velocity components with spatial scales less than
2$''$ that map $\sim2''$ northeast of the A and B symmetry axis. The redshifted
SiO is $\sim2''$ northwest of blueshifted SiO along a position angle of
$\sim135^o$ which is approximately parallel to the A and B symmetry axis. We
interpret the spatial position offset in red and blueshifted SiO emission as
due to rotation of a protostellar accretion disk and we derive $\sim$1.4
M$_{\odot}$ interior to the SiO emission. In the same vicinity, Mundy et al.
(1986) also concluded rotation of a nearly edge-on disk from OVRO observations
of much stronger and ubiquitous $^{13}$CO emission but the direction of
rotation is opposite to the SiO emission findings. Taken together, SiO and
$^{13}$CO data suggest evidence for a counter-rotating disk. Moreover, archival
BIMA array $^{12}$CO data show an inverse P Cygni profile with the strongest
absorption in close proximity to the SiO emission, indicating unambiguous
material infall toward the counter-rotating protostellar disk at a new source
location within the IRAS 16293-2422 complex. The details of these observations
and our interpretations are discussed.

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The categories of this paper are: quant-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: bayes-an
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The categories of this paper are: chem-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: comp-gas
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The categories of this paper are: math
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-th
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The categories of this paper are: math-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: gr-qc
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The categories of this paper are: q-fin
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The categories of this paper are: cs
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The categories of this paper are: ao-sci