Related papers: A variable magnetic disc wind in the black hole X-…
We present new insights about accretion and ejection physics based on joint RXTE/Chandra HETGS studies of rapid X-ray variability in GRS 1915+105. For the first time, with fast phase-resolved spectroscopy of the rho state, we are able to…
We report on a 120 ks Chandra/HETG spectrum of the black hole GRS 1915+105. The observation was made during an extended and bright soft state in June, 2015. An extremely rich disk wind absorption spectrum is detected, similar to that…
We analyze three observations of GRS 1915+105 in 2017 by Insight-HXMT when the source was in a spectrally soft state. We find strong absorption lines from highly ionized iron, which are due to absorption by disk wind outflowing at a…
Continuing our study of the role and evolution of accretion disc winds in the microquasar GRS 1915+105, we present high-resolution spectral variability analysis of the beta and gamma states with the Chandra High Energy Transmission Grating…
High resolution X-ray spectra of black hole X-ray binaries (BHBs) show blueshifted absorption lines from disk winds which seem to be equatorial. Winds occur in the Softer (disk-dominated) states of the outburst and are less prominent or…
The black hole X-ray binary GRS 1915+105 was bright for 26 years since its discovery and is well-known for its disk instabilities, quasi-periodic oscillations, and disk wind signatures. We report a long-term spectral-timing tracing of this…
The bright, erratic black hole X-ray binary GRS 1915+105 has long been a target for studies of disk instabilities, radio/infrared jets, and accretion disk winds, with implications that often apply to sources that do not exhibit its exotic…
We investigate accretion disk winds commonly observed in galactic black hole (BH) X-ray binaries (XRB), which manifest as blueshifted absorption features in X-ray spectra. We model these winds as ideal magnetohydrodynamic outflows of hot…
We present the results from simultaneous Chandra HETGS and RXTE observations of the microquasar GRS 1915+105 in its quasi-stable "soft state" (or State A) performed on 2007 August 14, several days after the state transition from "hard…
Accretion discs in strong gravity ubiquitously produce winds, seen as blueshifted absorption lines in the X-ray band of both stellar mass X-ray binaries (black holes and neutron stars), and supermassive black holes. Some of the most…
Black hole accretion disks appear to produce invariably plasma outflows that result in blue-shifted absorption features in their spectra. The X-ray absorption-line properties of these outflows are quite diverse, ranging in velocity from…
We report on Chandra gratings spectra of the stellar-mass black hole GRS 1915+105 obtained during a novel, highly obscured state. As the source entered this state, a dense, massive accretion disk wind was detected through strong absorption…
The black hole transient GRS 1915+105 entered a new phase of activity in 2018, generally characterised by low X-ray and radio fluxes. This phase has been only interrupted by episodes of strong and variable radio emission, during which high…
We analyze three prototypical black hole (BH) X-ray binaries (XRBs), \4u1630, \gro1655\ and \h1743, in an effort to systematically understand the intrinsic state transition of the observed accretion-disk winds between \windon\ and \windoff\…
We report on a detailed optical spectroscopic follow-up of the black hole transient MAXI J1820+070 (ASASSN-18ey). The observations cover the main part of the X-ray binary outburst, when the source alternated between hard and soft states…
X-ray signatures of outflowing gas have been detected in several accreting black-hole binaries, always in the soft state. A key question raised by these observations is whether these winds might also exist in the hard state. Here, we carry…
High inclination black hole X-ray binaries exhibit blueshifted ionized absorption lines from disk winds, whose launching mechanism is still in debate. The lines are predominantly observed in the high/soft state and disappear in the low/hard…
During its 2005 outburst, GRO J1655-40 was observed twice with the Chandra High Energy Transmission Grating Spectrometer; the second observation revealed a spectrum rich with ionized absorption lines from elements ranging from O to Ni…
Using high-resolution general relativistic magnetohydrodynamic (GRMHD) simulations, we investigate accretion flows around spinning black holes and identify three distinct accretion states. Our results suggest the origin of the complex…
Chandra obtained two High Energy Transmission Grating (HETG) spectra of the stellar-mass black hole GRO J1655-40 during its 2005 outburst, revealing a rich and complex disk wind. Soon after its launch, the Neil Gehrels Swift Observatory…