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Renewed radio emission from GRO J1655-40

ATel #443; M. P. Rupen (NRAO/GSFC), V. Dhawan, A. J. Mioduszewski (NRAO)
on 18 Mar 2005; 21:01 UT
Credential Certification: Michael P. Rupen (mrupen@nrao.edu)

Subjects: Radio, Binary, Black Hole, Transient

Referred to by ATel #: 487

The radio counterpart to the black hole X-ray binary GRO J1655-40 has again re-appeared, and is growing stronger (cf. ATEL #441). Observations taken at 4.86 GHz with the Very Large Array (VLA) showed a 1.77 +/- 0.07 mJy source on March 16th (13:38 to 14:29 UT), and a 3.6 +/- 0.1 mJy source on March 18th (12:59 to 13:10 UT). The latter represents the strongest radio emission so far during the current outburst. The radio emission remains optically thick, with a flux density at 8.46 GHz of 3.8 +/- 0.2 mJy on March 18th (13:19-13:26 UT), implying a quite small source. The full radio light curve is shown at:

http://www.aoc.nrao.edu/~mrupen/XRT/GRJ1655-40/grj1655-40.shtml

This radio re-appearance corresponds to the X-ray hardening visible in the XTE data (see the Web page referenced in ATEL #440). Further VLA observations will be added to the Web page referenced above, with any new surprises reported in another Astronomer's Telegram.

The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

GRO J1655-40 radio light curves