Related papers: Swift Observations of Shock Evolution in RS Ophiuc…
X-ray irradiation in X-ray binaries is thought to control the behavior at the outer disc, which is observable mainly at optical wavelengths. It is generally parameterized phenomenologically, but it can also be predicted from theoretical…
Very early observations with the Swift satellite of gamma-ray burst (GRB) afterglows reveal that the optical component is not detected in a large number of cases. This is in contrast to the bright optical flashes previously discovered in…
The early X-ray afterglow for a significant number of gamma-ray bursts detected by the Swift satellite is observed to have a phase of very slow flux decline with time ($F_\nu \propto t^{-\alpha}$ with $0.2 \lesssim \alpha \lesssim 0.8$) for…
Supergiant Fast X-ray Transients (SFXTs) are a sub-class of High Mass X-ray Binaries (HMXBs) associated with OB supergiant companions and displaying transient X-ray activity. This behaviour is quite surprising since HMXBs hosting…
Aims: The launch of Swift has allowed many more novae to be observed regularly over the X-ray band. Such X-ray observations of novae can reveal ejecta shocks and the nuclear burning white dwarf, allowing estimates to be made of the ejecta…
Optical spectra of the 2006 outburst of RS Ophiuchi beginning one day after discovery to over a year after the outburst are presented here. The spectral evolution is found to be similar to that in previous outbursts. The early phase spectra…
We present an update on the results of our monitoring observations of the X-ray remnant of supernova (SN) 1987A with the {\it Chandra X-Ray Observatory}. As of 2002 December, we have performed a total of seven observations of SN 1987A. The…
We present low-frequency radio observations of the Galactic symbiotic recurrent nova RS Ophiuchi during its 2021 outburst. The observations were carried out with the upgraded Giant Metrewave Radio Telescope (uGMRT) spanning a frequency…
We report on the temporal and spectral characteristics of the early X-ray emission from the Gamma Ray Burst 051117A as observed by Swift. The superb quality of the early X-ray light-curve and spectra of this source, one of the brightest…
We have carried out detailed analysis on the black hole candidate (BHC) X- ray transient Swift J1753.5-0127 observed by the Rossi X-Ray Timing Explorer (RXTE) during its outburst in 2005 {2006. The spectral analysis shows that the emissions…
We report low-frequency radio observations of the 2021 outburst of the recurrent nova RS Ophiuchi. These observations include the lowest frequency observations of this system to date. Detailed light curves are obtained by MeerKAT at 0.82…
The Be X-ray pulsar, SMC X-3 underwent a giant outburst from 2016 August to 2017 March, which was monitored with the Swift satellite. During the outburst, its broadband flux increased dramatically, and the unabsorbed X-ray luminosity…
We describe how the various outcomes of stellar tidal disruption give rise to observable radiation. We separately consider the cases where gas circularizes rapidly into an accretion disc, as well as the case when shocked debris streams…
Extended emission is a mystery in short gamma-ray bursts (SGRBs). By making time resolved spectral analyses of brightest nine events observed by ${\it Swift}$ XRT, we obviously classify the early X-ray emission of SGRBs into two types. One…
The low-mass X-ray binary GS 1826-238 is presently unique for its consistently regular bursting behavior. In previous Rossi X-Ray Timing Explorer (RXTE) measurements between 1997 November and 2002 July, this source exhibited (nearly)…
We report on the detailed study of the 2008 October outburst from the anomalous X-ray pulsar (AXP) 1E 1547.0-5408 discovered through the Swift/Burst Alert Telescope (BAT) detection of SGR-like short X-ray bursts on 2008 October 3. The…
We present near-IR photo-spectroscopy in the H and K bands of the 2006 outburst of the recurrent nova RS Ophiuchi (RS Oph). The observations cover the period between 1 to 94 days after the eruption. The near IR light curve and an extensive…
X-Ray Flashes (XRFs) are soft gamma-ray bursts whose nature is not clear. Their soft spectrum can be due to cosmological effects (high redshift), an off-axis view of the jet or can be intrinsic to the source. We use SWIFT observations to…
We report the Fermi-LAT gamma-ray detection of the 2021 outburst of the symbiotic recurrent nova RS Ophiuchi. In this system, unlike classical novae from cataclysmic binaries, the ejecta from the white dwarf form shocks when interacting…
In a dwarf nova, the accretion disk around the white dwarf is a source of ultraviolet, optical, and infrared photons, but is never hot enough to emit X-rays. Observed X-rays instead originate from the boundary layer between the disk and the…