Related papers: A persistent disk wind and variable jet outflow in…
Neutron star X-ray binaries emit a compact, optically thick, relativistic radio jet during low-luminosity, usually hard states, as Galactic black-hole X-ray binaries do. When radio emission is bright, a hard power-law tail without evidence…
All disc-accreting astrophysical objects produce powerful outflows. In binaries containing neutron stars (NS) or black holes, accretion often takes place during violent outbursts. The main disc wind signatures during these eruptions are…
We studied and compared the long-term average hard X-ray (>20keV) spectra of a sample of twelve bright low-mass X-ray binaries hosting a neutron star (NS). Our sample comprises the six well studied Galactic Z sources and six Atoll sources,…
Recent observations of the deeply embedded L1551 IRS5 system permit the detailed examination of the properties of both the stellar binary and the binary jet. For the individual components of the stellar binary, we determine their masses,…
The luminous narrow line Seyfert galaxy PG1211+143 was the first non-BAL AGN to reveal a powerful ionized wind, based on early observations with ESA's XMM-Newton X-ray Observatory. Subsequent observations, mainly with XMM-Newton and the…
Compact radio jets are ubiquitous in stellar-mass black-hole binaries in their hard spectral state. Empirical relations between the radio and narrow-band X-ray fluxes have been used to understand the connection between their accretion discs…
We present infrared spectroscopy of the low-mass X-ray binary GX 1+4/V2116 Oph. This symbiotic binary consists of a 2-min accretion-powered pulsar and an M5 III red giant. A strong He I 1.083 micron emission line with a pronounced P Cygni…
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…
The brightest ultraluminous X-ray source currently known, HLX-1, has been observed to undergo five outburst cycles. The periodicity of these outbursts, and their high inferred maximum accretion rates of $\sim{\rm few}\times 10^{-4} M_\odot…
During the bright outburst in 2011, the black hole candidate IGR J17091-3624 exhibited strong quasi-periodic flare-like events (on timescales of tens of seconds) in some characteristic states, the so-called heartbeat state. From the…
In this paper we survey the theory of wind accretion in high mass X-ray binaries hosting a magnetic neutron star and a supergiant companion. We concentrate on the different types of interaction between the inflowing wind matter and the…
High-Mass X-ray Binaries (HMXBs) offer a unique opportunity for the investigation of accretion onto compact objects and of wind structure in massive stars. A key source for such studies is the bright neutron star HMXB Vela X-1 whose…
The Rapid Burster is a unique neutron star low-mass X-ray binary system, showing both thermonuclear Type-I and accretion-driven Type-II X-ray bursts. Recent studies have demonstrated how coordinated observations of X-ray and radio…
We report a broadband investigation of the Z-type neutron star (NS) low mass X-ray binary (LMXB) GX 349+2 using AstroSat and NICER. AstroSat observed the source exhibiting large scale variability in its normal branch (NB) /flaring branch…
We studied the relation of accretion-jet power and disk luminosity, especially the jet efficiencies and disk radiative efficiencies for different accretion disks as well as black hole (BH) spin, in order to explore the origin of radio…
GRS 1915+105 is a transient black hole X-ray binary consistently emitting 10-100% of the Eddington luminosity in the X-ray band during the last three decades until mid-2018 when the source luminosity suddenly decreased by an order of…
Time-resolved optical and infrared polarimetric observations of black hole and neutron star low-mass X-ray binaries are presented. Data were acquired with the VLT, UKIRT and HIPPO on the SAAO 1.9-m. We find that for some sources in…
The connection between the accretion process that powers AGN and the formation of jets is still poorly understood. Here we tackle this issue using new, deep \chandra and \xmm observations of the cores of three powerful radio loud quasars:…
We examine a systematic comparison of jet-knots, hotspots and radio lobes recently observed with Chandra and ASCA. This report will discuss the origin of their X-ray emissions and investigate the dynamics of the jets. The data was compiled…
We investigate the accretion geometry in neutron star low-mass X-ray binaries (LMXBs) in the hard spectral state. It is commonly accepted that, for low mass transfer rates, an advection-dominated accretion flow (ADAF) is present in the…