Continued slow radio rise of GRO J1655-40

ATel #434; M. P. Rupen (NRAO/GSFC), A. J. Mioduszewski, V. Dhawan (NRAO)
on 1 Mar 2005; 15:41 UT
Credential Certification: Michael P. Rupen (mrupen@nrao.edu)

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We report further Very Large Array (VLA) observations of the black hole X-ray binary GRO J1655-40. Data taken on Feb. 27th from 11:40 through 13:40 UT (during the X-ray plateau seen by INTEGRAL [ATEL #432] and RXTE [ATEL #433]) show the radio source steady to within 10%, with flux densities of 1.86 +/- 0.17, 1.80 +/- 0.06, and 1.57 +/- 0.05 mJy at 1.425, 4.860, and 8.460 GHz, respectively. Quasi-simultaneous observations at 22.460 GHz were not useful, due to a combination of weather conditions and the low elevation of the source. The radio source has continued its roughly linear rise since the first radio detection on Feb. 20th (ATEL #419), and retains a fairly flat (optically thick) spectrum. The slow (~30%) rise in the radio contrasts with the X-ray flux, which has roughly doubled over the same period (ATEL #433) in both the 2-10 and 10-60 keV bands. Further radio observations are planned, and will be posted (together with the results so far) at:

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

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

Radio observations of GRO J1655-40