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Radio detection of GRO J1655-40

ATel #419; M. P. Rupen (NRAO/GSFC), V. Dhawan, A. J. Mioduszewski (NRAO)
on 21 Feb 2005; 19:44 UT
Credential Certification: Michael P. Rupen (mrupen@nrao.edu)

Subjects: Radio, Binary, Black Hole, Transient

Referred to by ATel #: 425, 434, 437, 487

We report the detection of renewed radio activity associated with the black hole X-ray binary GRO J1655-40, currently undergoing an X-ray (ATEL #414; ATEL #415) and optical/infrared (ATEL #417, ATEL #418) flare. Very Large Array (VLA) observations taken on Feb. 20th (MJD 53421.6) under poor weather conditions clearly detect a 1.4+/-0.2 mJy source at the position of GRO J1655-40 at 4.86 GHz, and a corresponding 1.1+/-0.4 mJy source (uncertainties dominated by phase errors) at 8.46 GHz. There is no obvious extension with our 5.35 x 2.67 arcsec beam (oriented -5 degrees east of north) at 4.86 GHz; the 8.46 GHz do not place any useful limit. Our last previous observations were made on 4 January 2005 (MJD 53374.6) at 4.86 GHz, yielding a non-detection with an rms noise of 0.13 mJy/beam. Further radio observations are planned.

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