AAS 201st Meeting, January, 2003
Session 15. Black Holes Observed and Modeled
Poster, Monday, January 6, 2003, 9:20am-6:30pm, Exhibit Hall AB

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[15.08] A New Jet-Producing State in the Microquasar GRS 1915+105

D.M. Rothstein, S.S. Eikenberry (Cornell), K. Matthews (Caltech)

We report simultaneous, high time resolution infrared and X-ray observations of the Galactic microquasar GRS 1915+105 on 27-30 July 2002 UTC, using the Palomar 200-inch telescope and the Rossi X-ray Timing Explorer. GRS 1915+105 was observed in a jet-producing state that shares some characteristics with previous observations (e.g. Eikenberry et al. 1998) but also has striking differences. The X-ray light curves and spectra differ from those previously observed during jet ejection events (they consist of the "class alpha" state defined by Belloni et al. 2000, as opposed to "class beta"), indicating different behavior within the accretion disk. In both cases, however, infrared flares corresponding to jet ejection are spurred by a sharp X-ray "spike" of duration several seconds. The infrared data from 2002 show quasi-periodic flaring on 15-30 minute timescales with dereddened amplitudes on the order of 40 mJy -- similar to the Eikenberry et al. (1998) data but with amplitudes lower by a factor of a few. The profiles of the 2002 flares also differ from previous observations; they are more likely to be asymmetric, with fast rise times and gradual decays. We discuss the relevance of these observations for models of jet formation and accretion disk evolution in microquasars. With these data, we can begin to "map out" how the many different X-ray states of GRS 1915+105 affect jet production in this unusual source.

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Bulletin of the American Astronomical Society, 34, #4
© 2002. The American Astronomical Soceity.