Related papers: Long-term Multi-wavelength Observations of GRS 175…
We report on an XMM-Newton Reflection Grating Spectrometer observation of the black hole candidate and Galactic microquasar GRS 1758-258. The source entered a peculiar "off/soft" state in late February, 2001, in which the spectrum softened…
GRS 1758-258 is one of the few persistent hard X-ray emitters (E>100 keV) in the Galaxy. Using the ASCA satellite, we have obtained the first detailed data on GRS 1758-258 in the 1-10 keV range, where previous observations were affected by…
We present the results of a BeppoSAX observation of the black hole candidate GRS1758-258 carried out in 1997, while the source was in its low/hard state. The X-ray spectrum, simultaneously observed over the broad energy range from 0.1 to…
Following a series of deep observations of the Galactic Bulge region performed with the Wide Field Cameras on board BeppoSAX, it has been possible to study throughout a long time period a number of persistent X-ray sources. We report on the…
In spite of increasing evidences of the presence of a massive Black Hole at the Galactic Center, its radio counterpart, Sgr A*, shows little activity at high energies, and recent models involving energy advection (ADAF) have been proposed…
We present the results of a broadband (0.5-78 keV) X-ray spectral study of the persistent Galactic black hole X-ray binary GRS 1758-258 observed simultaneously by Swift and NuSTAR. Fitting with an absorbed power-law model revealed a broad…
The results of GRANAT/SIGMA hard X-ray observations of GRS 1758-258 in 1990-1998 are presented. The source lies at ~5\arcdeg from the Galactic Center and was within the SIGMA field of view during the GRANAT surveys of this region. The total…
Context. GRS 1758-258 is one of two prototypical microquasars towards the Galactic Center direction discovered almost a quarter of a century ago. The system remains poorly studied in the optical domain due to its counterpart being a very…
We report the results of our multi-wavelength observations of GRS 1758-258 made in August 1997. The energy bands include radio, millimeter, X-ray, and gamma-ray. The observations enable us to obtain a complete spectrum of the source over an…
We present the spectral and timing evolution of the persistent black hole X-ray binary GRS 1758-258 based on almost 12 years of observations using the Rossi X-ray Timing Explorer Proportional Counter Array. While the source was…
We present the results of a radio and X-ray study of the Galactic microquasar GRS 1758-258, using unpublished archival data and new observations. We focus in particular on the 2000-2002 state transitions, and on its more quiet behaviour in…
We report on long-term observations of the Galactic-bulge black hole candidates 1E 1740.7-2942 and GRS 1758-258 with the Rossi X-Ray Timing Explorer. 1E 1740.7-2942 has been observed 77 times and GRS 1758-258 has been observed 82 times over…
The Galactic Center black hole candidate (BHC) GRS 1758-258 has been observed extensively within INTEGRAL's Galactic Center Deep Exposure (GCDE) program in 2003 and 2004, while also being monitored with RXTE. We present quasi-simultaneous…
We discuss a series of observations of the black hole candidate GX 339-4 in low luminosity, spectrally hard states. We present spectral analysis of three separate archival Advanced Satellite for Cosmology and Astrophysics (ASCA) data sets…
We observed the "micro-quasar" GRS 1758-258 four times with Chandra. Two HRC-I observations were made in 2000 September-October spanning an intermediate-to-hard spectral transition (identified with RXTE). Another HRC-I and an ACIS/HETGS…
Near the end of 2001 February, the black-hole candidate (BHC) GRS 1758-258 made an abrupt transition from a standard hard (low) state to a soft state. Unlike Cyg X-1 and other BHCs, whose luminosity increases during this transition, GRS…
Recently it has been suggested that the hard x-ray power-law tails exhibited in the ASCA spectra of several nearby giant elliptical galaxies are caused by low-radiative efficiency accretion flows (ADAFs) onto a massive black hole in the…
We present results from observations of persistent black hole candidates with the High Energy Transmission Gratings aboard the Chandra X-ray Observatory. The sources include LMC X-1, LMC X-3, GRS 1758-258, and Cyg X-1. Along with the…
We study spectra produced by weakly accreting black hole (BH) systems using the semi-analytic advection dominated accretion flow (ADAF) model and the general-relativistic magentohydrodynamic (GRMHD) simulation. We find significant…
We present the results on broadband X-ray properties of persistent black hole binaries GRS 1758$-$258 and 1E 1740.7$-$2942 using AstroSat, NuSTAR and Swift-XRT observations carried out during 2016$-$2022. We perform spectral modeling of…