Related papers: A Disk--Jet interaction model for the X--Ray Varia…
We analyze X-ray light curves of the blazar Mrk 421 obtained from the Soft X-ray Imaging Telescope and the Large Area X-Ray Proportional Counter instrument onboard the Indian space telescope $AstroSat$ and archival observations from…
Black hole X-ray binaries display significant stochastic variability on short time-scales (0.01-100 seconds), with a complex pattern of lags in correlated variability seen in different energy bands. This behaviour is generally interpreted…
The power spectral density (PSD) of the X-ray emission variability from the accretion disc-corona region of black hole X-ray binaries and active galactic nuclei has a broken power law shape with a characteristic break time-scale. If the…
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…
In this work we develop a lepto-hadronic model for the electromagnetic radiation from jets in microquasars with low-mass companion stars. We present general results as well as applications to some specific systems, and carefully analyze the…
Interaction of intense radiation from the underlying accretion disc with steady, general-relativistic jet is studied. The radiation field imparts momentum as well as energy on to the outflowing jet under Compton scattering. As a result, the…
Large-scale, decelerating, relativistic X-ray jets due to material ejected from the black-hole candidate X-ray transient and microquasar XTE J1550-564 has been recently discovered with Chandra by Corbel et al. (2002). We find that the…
Multi-wavelength observations of the black hole X-ray binary XTE J1118+480 have offered abundant spectral and timing information about the source, and have thus provided serious challenges to theoretical models. We propose a coupled…
We show that with the wind/jet activity, the spectral index of hard X-ray is changed in galactic microquasars. When mass loss takes place, the spectrum becomes softer and when mass gain takes place, the spectrum becomes harder. We present…
The wide-band X-ray spectra of the high mass X-ray binary Cygnus X-3 exhibits a pivoting behavior in the `low' (as well as `hard') state, correlated to the radio emission. The time scale of the soft and hard X-rays' anti-correlation, which…
The large mechanical luminosity of the jets of GRS 1915+105 should give rise to luminous emission regions, similar to those observed in radio galaxies, where the jets interact with the gas surrounding the source. However, no radio…
We present results based on the first 20 Chandra images obtained in a survey of jets in radio selected flat-spectrum quasars (FSRQs), along with new sub-arcsecond radio maps and optical images. We discover jet X-ray flux in 12 sources…
We have discovered at x-ray and radio wavelengths large-scale moving jets from the microquasar XTE J1550-654. Plasma ejected from near the black hole traveled at relativistic velocities for at least four years. We present direct evidence…
I reexamine recent observations of velocity profiles across jets blown by young stellar objects, and argue that the observations do not support the interpretation of jets rotating around their symmetry axes. Instead, I propose that the…
The observed radio-optical-X-ray spectral energy distributions (SEDs) of 22 hot spots and 45 knots in the jets of 35 active galactic nuclei are complied from literature and modeled with single-zone lepton models. It is found that the…
The Galactic microquasar GRS 1915+105 exhibits several episodes of steady X-ray emission characterized by a hard power-law spectrum and intense Quasi Periodic Oscillations. It is known that there are two types of such low-hard states, one…
In the subclass of high-mass X-ray binaries known as "microquasars", relativistic hadrons in the jets launched by the compact object can interact with cold protons from the star's radiatively driven wind, producing pions that then quickly…
A new class of X-ray sources was clearly established with the discovery of highly relativistic radio jets from the galactic sources GRS 1915+105 and GRO J1655-40. Both of these objects have given us a broader view of black holes and the…
We present a timing analysis of two Rossi X-ray Timing Explorer observations of the microquasar GRS 1915+105 during the heartbeat state. The phase-frequency-power maps show that the intermediate-frequency aperiodic X-ray variability weakens…
We treat transformation properties of external radiation fields in the proper frame of a plasma moving with constant speed. The specific spectral energy densities of external isotropic and accretion-disk radiation fields are derived in the…