Comptel Observations of Gro J1655-40
نویسندگان
چکیده
GRO J1655-40 is a transient black-hole candidate that has been shown to eject matter at apparently superluminal velocities. OSSE spectra measured during X-ray outbursts are consistent with a single power law up to 600 keV, with no evidence for a high-energy cutoo. Flaring behaviour of GRO J1655-40 has also been claimed to be detected up to 10 MeV during observations with the balloon-borne HIREGS instrument in January 1995. Here we present the analysis of COMPTEL observations (0.75{30 MeV) of this source. Before April 1996, GRO J1655-40 was in the eld-of-view of COMPTEL during 50 CGRO viewing periods. We present upper limits on the time-averaged emission from GRO J1655-40 and also search for-ray ares in 200 intervals of two days each.
منابع مشابه
On the distance of GRO J 1655 - 40 ⋆
Aims. We challenge the accepted distance of 3.2 kpc of GRO J1655-40. We present VLT-UVES spectroscopic observations to estimate the absorption toward the source, and determine a maximum distance of GRO J1655-40. Methods. We show that the accepted value of 3.2 kpc is taken for granted by many authors. We retrieved in the ESO archive UVES spectra taken in April 2004 when GRO J1655-40 was in quies...
متن کاملThe Transient Nature of Gro J1655-40 and Its Evolutionary State
We consider the evolutionary state of the black–hole X–ray source GRO J1655–40 in the context of its transient nature. Recent optical observations show that the donor in GRO J1655–40 is an intermediate–mass star (≃ 2.3M⊙) crossing the Hertzsprung gap. Usually in such systems the donor’s radius expansion drives a near-Eddington or super–Eddington mass transfer rate which would sustain a persiste...
متن کاملAND ASTROPHYSICS The radio surroundings of the microquasar GRO J1655−40
We report the results of a study of the radio surroundings of the superluminal microquasar GRO J1655−40. We have searched for extended continuum structures that might be indicative of the presence of a supernova remnant (SNR) associated with the formation of the compact object in the binary system. We also carried out HI-line observations of the region looking for a local minimum created by an ...
متن کاملar X iv : a st ro - p h / 97 12 02 6 v 1 2 D ec 1 99 7 1 Absorption dips in GRO J 1655 − 40 : mapping the inner accretion disk
Using the RXTE PCA we discovered dips in the X-ray light curves of the black-hole candidate GRO J1655−40 during outburst. They are short (∼minute) and deep (down to ∼8% of the out-of-dip intensity). Similar kind of dips were found in 90 s measurements of the RXTE ASM during the same outburst. The occurrences of the dips are consistent with the optically determined orbital period, and were found...
متن کاملObservations of Gamma-Ray Outbursts from Galactic Microquasars
The BATSE earth-occultation database provides nine years of coverage for 75 γ-ray sources in the energy range 35− 1700 keV. For transient sources, this long time-base dataset makes it possible to study the repeated outbursts from individual objects. We have used the JPL data analysis package EBOP (Enhanced BATSE Occultation Package) to derive the light curves and the time evolution of the spect...
متن کامل