Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Triple trouble for XZ Tau: deep imaging with the Jansky Very Large Array   We present new observations of the XZ Tau system made at high angular
resolution (55 milliarcsec) with the Karl G. Jansky Very Large Array (VLA) at a
wavelength of 7 mm. Observations of XZ Tau made with the VLA in 2004 appeared
to show a triple system, with XZ Tau A resolved into two sources, XZ Tau A and
XZ Tau C. The angular separation of XZ Tau A and C (0.09 arcsec) suggested a
projected orbital separation of around 13 AU with a possible orbital period of
around 40 yr. Our observations were obtained approximately 8 yr later, a fifth
of this putative orbital period, and should therefore allow us to constrain the
orbit of XZ Tau C, and evaluate the possibility that a recent periastron
passage of C coincided with the launch of extended optical outflows from XZ Tau
A. Despite improved sensitivity and resolution compared with previous
observations, we find no evidence of XZ Tau C in our data. Components A and B
are detected with a signal-to-noise ratio greater than ten; their orbits are
consistent with previous studies, although the emission from XZ Tau A appears
to be weaker. Three possible interpretations are offered: either XZ Tau C is
transiting XZ Tau A, which is broadly consistent with the periastron passage
hypothesis, or the emission seen in 2004 was that of a transient, or XZ Tau C
does not exist. A fourth interpretation, that XZ Tau C was ejected from the
system, is dismissed due to the lack of angular momentum redistribution in the
orbits of XZ Tau A and XZ Tau B that would result from such an event. Our
observations are insufficient to distinguish between the remaining
possibilities, at least not until we obtain further VLA observations at a
sufficiently later time. A further non-detection would allow us to reject the
transit hypothesis, and the periastron passage of XZ Tau C as agent of XZ Tau
A's outflows.

28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
4
The categories of this paper are: cond-mat
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
3
The categories of this paper are: physics
15
The categories of this paper are: nucl-ex
24
The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th
0
The categories of this paper are: hep-ph
14
The categories of this paper are: math-ph
21
The categories of this paper are: adap-org
37
The categories of this paper are: supr-con