Related papers: Resolved, expanding jets in the Galactic black hol…
Black hole X-ray binaries in the quiescent state (Eddington ratios typically $\lesssim$10$^{-5}$) display softer X-ray spectra (photon indices $\Gamma\sim2$) compared to higher-luminosity black hole X-ray binaries in the hard state…
We propose a jet model for the low/hard state of Galactic black-hole X-ray sources that can explain the energy spectra from radio to X-rays. The model assumes that i) there is a magnetic field along the axis of the jet; ii) the electron…
A solid theoretical understanding of how inflowing, accreting plasma around black holes and other compact objects gives rise to outflowing winds and jets is still lacking, despite decades of observations. The fact that similar processes and…
We present HST, RXTE, and UKIRT observations of the broad band spectra of the black hole X-ray transient XTE J1859+226 during the decline from its 1999-2000 outburst. Our UV spectra define the 2175A interstellar absorption feature very well…
During outbursts, the observational properties of black hole X-ray binaries (BHXBs) vary on timescales of days to months. These relatively short timescales make these systems ideal laboratories to probe the coupling between accreting…
Most active galactic nuclei at the center of the nearby galaxies have super-massive black holes accreting at sub-Eddington rates through hot accretion flows or radiatively inefficient accretion flows, which efficiently produce jets. The…
In recent years, an increasing number of proper motions have been measured for Galactic X-ray binaries. When supplemented with accurate determinations of the component masses, orbital period, and donor luminosity and effective temperature,…
Stellar-mass black holes with relativistic jets, also known as microquasars, mimic the behavior of quasars and active galactic nuclei. Because timescales around stellar-mass black holes are orders of magnitude smaller than those around more…
We present observations of a major outburst at centimeter, millimeter, optical, X-ray, and gamma-ray wavelengths of the BL Lacertae object AO 0235+164 in 2008. We analyze the timing of multi-waveband variations in the flux and linear…
On 28 February 2007 a new outburst of the previously known transient source XTE J1856+053 was detected with RXTE/ASM. We present here the results of an XMM-Newton (0.5-10.0 keV) Target of Opportunity observation performed on 14 March 2007,…
We report the detection of extended X-ray emission from two high-redshift radio quasars. These quasars, J1405+0415 at $z$=3.208 and J1610+1811 at $z$=3.118, were observed in a Chandra snapshot survey selected from a complete sample of the…
We report results from Chandra observations analyzed for evidence of variability and proper motion in the X-ray jet of Centaurus A. Using data spanning 15 years, collective proper motion of $11.3\pm3.3$ mas yr$^{-1}$, or $0.68\pm0.20c$, is…
The mid-infrared (MIR; $\lambda\simeq3 - 10\mu$m) bands offer a unique window into understanding accretion and its interplay with jet formation in Galactic black hole X-ray binaries (BHXRBs). Although extremely difficult to observe from the…
The Galactic black hole transient GRS1915+105 is famous for its markedly variable X-ray and radio behaviour, and for being the archetypal galactic source of relativistic jets. It entered an X-ray outburst in 1992 and has been active ever…
A black hole x-ray binary (XRB) system forms when gas is stripped from a normal star and accretes onto a black hole, which heats the gas sufficiently to emit x-rays. We report a polarimetric observation of the XRB Cygnus X-1 using the…
We report on simultaneous radio and X-ray observations of the black hole candidate XTE J1650-500 during the course of its 2001-2002 outburst. The scheduling of the observations allowed us to sample the properties of XTE J1650-50 in…
Some X-shaped radio galaxies show a Z-symmetric morphology in the less luminous secondary lobes. Within the scenario of a merger between two galaxies, each hosting a supermassive black hole in its center, this structure has been explained…
Radio emission from X-ray binary systems (XRBs) has developed in recent years from being peculiar phenomenon to being recognised as an ubiquitous property of several classes of XRBs. In this scenario the synchrotron emission is interpreted…
The radio:X-ray correlation that characterises accreting black holes at all mass scales - from stellar mass black holes in binary systems to super-massive black holes powering Active Galactic Nuclei - is one of the most important pieces of…
The radio emitting X-ray binary GRS 1915+105 shows a wide variety of X-ray and radio states. We present a decade of monitoring observations, with the RXTE-ASM and the Ryle Telescope, in conjunction with high-resolution radio observations…