Query : 2001A&A...372..793V

2001A&A...372..793V - Astronomy and Astrophysics, volume 372, 793-802 (2001/6-4)

Spectral differences between the radio-loud and radio-quiet low-hard states of GRS 1915+105: Possible detection of synchrotron radiation in X-rays.


Abstract (from CDS):

The Galactic microquasar GRS 1915+105 exhibits several episodes of steady X-ray emission characterized by a hard power-law spectrum and intense Quasi Periodic Oscillations. It is known that there are two types of such low-hard states, one with steady radio emission and the other without any significant radio emission. We present the results of a detailed X-ray spectroscopic study of GRS 1915+105, using data from the Rossi X-ray Timing Explorer obtained during various episodes of the low-hard states of the source. We show that there are distinct X-ray spectral differences between the radio-quiet and radio-loud low-hard states of the source. The X-ray spectra of the radio-quiet low-hard state is best described by a model consisting of a multicolor disk-blackbody and a Comptonized component, whereas the X-ray spectra of radio-loud low-hard state requires a model consisting of three components: a multicolor disk-blackbody, a Comptonized component and a power-law, for statistically and physically acceptable fits. We attempt to model the presence of this additional power-law component as due to synchrotron radiation which is responsible for the radio and infrared radiation from the source. We show that a simple adiabatically expanding jet model for the synchrotron radiation can account for the observed X-ray flux for reasonable values of the magnetic field and the mass outflow rate. This is the first report of detection of the synchrotron radiation in the X-ray band for this source.

Abstract Copyright:

Journal keyword(s): accretion, accretion disks - black hole physics - stars: winds, outflows - stars: individual: GRS 1915+105 - X-rays: stars

Simbad objects: 2

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Number of rows : 2
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 V* KV UMa HXB 11 18 10.7930420496 +48 02 12.314730120     12.25     K5V-M1V 802 0
2 Granat 1915+105 HXB 19 15 11.55576 +10 56 44.9052           ~ 2559 0

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