Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Accelerating a water maser face-on jet from a high mass young stellar
  object   We report on a long-term single-dish and VLBI monitoring for intermittent
flare activities of a Dominant Blue-Shifted H$_{2}$O Maser (DBSM) associated
with a southern high mass young stellar object, G353.273+0.641. Bi-weekly
single-dish monitoring using Hokkaido University Tomakomai 11-m radio telescope
has shown that a systematic acceleration continues over four years beyond a
lifetime of individual maser features. This fact suggests that the H$_{2}$O
maser traces a region where molecular gas is steadily accelerated. There were
five maser flares during five-years monitoring, and maser distributions in four
of them were densely monitored by the VLBI Exploration of Radio Astrometry
(VERA). The overall distribution of the maser features suggests the presence of
a bipolar jet, with the 3D kinematics indicating that it is almost face-on
(inclination angle of $\sim$ 8$^{\fdg}$--17$^{\fdg}$ from the line-of-sight).
Most of maser features were recurrently excited within a region of
100$\times$100 AU$^{2}$ around the radio continuum peak, while their spatial
distributions significantly varied between each flare. This confirms that
episodic propagations of outflow shocks recurrently invoke intermittent flare
activities. We also measured annual parallax, deriving the source distance of
1.70 $^{+0.19}_{-0.16}$ kpc that is consistent with the commonly-used
photometric distance.

12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph
19
The categories of this paper are: eess
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
18
The categories of this paper are: econ
23
The categories of this paper are: solv-int
24
The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th