Further radio observations of H1743-322
ATel #1352; M. P. Rupen, V. Dhawan, A. J. Mioduszewski (NRAO)
on 9 Jan 2008; 21:30 UT
Credential Certification: Michael P. Rupen (firstname.lastname@example.org)
Subjects: Radio, X-ray, Black Hole, Transient
Observations with the Very Large Array (VLA) in its moderately extended 'B'
configuration confirm the radio outburst of the black hole transient
H1743-322 reported in ATel #1349, following the X-ray outburst reported
in ATel #1348. The flux densities on Jan. 7 were 15.5 +/- 0.2 mJy at
4.86 GHz and 13.58 +/- 0.13 mJy at 8.46 GHz, somewhat lower than seen by
Corbel & Tzioumis on Jan. 3 (ATel #1349); the errors quoted here are
statistical, but the absolute flux densities are uncertain at the 5-10%
level. The radio spectrum is thus flatter (flux density going as
nu^-0.2) than on Jan. 3, suggesting another outburst occurred between these
two radio observations.
The VLA observations give a marginal detection of linear polarization
at the 4 +/- 1% level at 8.46 GHz, and a nominal value of 1 +/- 1%
at 4.86 GHz. As expected, neither frequency shows any circularly polarized
emission, with 1-sigma limits of about 0.8% in both cases.
The source is unresolved in these images, which had a resolution at 8.46 GHz
of about 1.8 x 0.9 arcsec, oriented roughly north-south. Gaussian fits
yield an upper limit to the source size of 0.25 arcsec at 8.46 GHz.
Further VLA observations are on-going.
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