1998A&AS..128..145P


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.10CEST09:34:00

1998A&AS..128..145P - Astron. Astrophys., Suppl. Ser., 128, 145-151 (1998/February-2)

X-ray variability of GRS 1915+105 during the low-hard state observed with the Indian X-ray astronomy experiment (IXAE).

PAUL B., AGRAWAL P.C., RAO A.R., VAHIA M.N., YADAV J.S., MARAR T.M.K., SEETHA S. and KASTURIRANGAN K.

Abstract (from CDS):

The galactic superluminal transient X-ray source GRS 1915+105 was observed with the pointed proportional counters (PPCs) onboard the Indian satellite IRS-P3 during 1996 July 23-27. We report here details of the behavior of this source during the relatively quiet and low luminosity state. Large intensity variations by a factor of 2 to 3, generally seen in black-hole candidates, are observed at a time scale of 100 ms to few seconds. No significant variation is detected over larger time scale of minute or more. The intensity variations are described as sum of shots in the light curve, and the number distribution of the shots are found to be exponential function of the fluence and duration of the shots. The cross correlation spectrum between 6-18keV and 2-6keV X-rays is found to have asymmetry signifying a delay of the hard X-rays by about 0.2 to 0.4s. This supports the idea of hard X-rays being generated by Compton up-scattering from high energy clouds near the source of soft X-rays. Very strong and narrow quasi periodic oscillations in the frequency range 0.62 to 0.82Hz are observed. We discuss about a model which explains a gradual change in the QPO frequencies with corresponding changes in the mass accretion rate of the disk.

Abstract Copyright:

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

Simbad objects: 6

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Number of rows : 6

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 V* V518 Per HXB 04 21 42.7231318463 +32 54 26.936934166 13.00 13.50 13.2     M4.5V 620 1
2 X LMC X-1 HXB 05 39 38.8285930597 -69 44 35.533031148   14.8 14.5     O8(f)p 560 2
3 V* GU Mus HXB 11 26 26.5947467816 -68 40 32.888148788           K3V-K7V 670 1
4 V* V821 Ara HXB 17 02 49.3810714542 -48 47 23.163091737 16.20 16.30 15.5     ~ 1764 0
5 Granat 1915+105 LXB 19 15 11.54938 +10 56 44.7585           ~ 2284 0
6 HD 226868 HXB 19 58 21.6758193269 +35 12 05.782512305 9.38 9.72 8.91 8.42   O9.7Iabpvar 3924 0

    Equat.    Gal    SGal    Ecl

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