Related papers: Pile-up correction for the Swift-XRT observations …
With respect to the recent INTEGRAL/IBIS 9-year Galactic Hard X-ray Survey (Krivonos et al. 2012), we use archival Swift/XRT observations in conjunction with multi-wavelength information to discuss the counterparts of a sample of newly…
For bright transients such as Gamma-Ray Bursts (GRBs), the Ultra-Violet/Optical Telescope (UVOT) operates under event mode at early phases, which records incident positions and arrival time for each photon. The event file is able to be…
As the number of observed Gamma-Ray Bursts (GRBs) continues to grow, follow-up resources need to be used more efficiently in order to maximize science output from limited telescope time. As such, it is becoming increasingly important to…
The rapid acquisition of positions by the upcoming Swift satellite will allow the monitoring for X-ray lines in GRB afterglows at much earlier epochs than was previously feasible. We calculate the possible significance levels of iron line…
We present new results of uniform spectral analysis of Swift/XRT observations of the X-ray binary system 4U 1957+11. This includes 26 observations of the source made between MJD 54282$-$55890 (2007 July 01 $-$ 2011 November 25). All 26…
This paper discusses Swift observations of the gamma-ray burst GRB 050315 (z=1.949) from 80 s to 10 days after the onset of the burst. The X-ray light curve displayed a steep early decay (t^-5) for ~200 s and several breaks. However, both…
I describe the modifications to the standard forward-shock model required to account for the X-ray light-curve features discovered by Swift in the early afterglow emission and propose that a delayed, pair-enriched, and highly relativistic…
A new accreting millisecond X-ray pulsar, IGR J17511-3057, was discovered in outburst on 2009 September 12 during the INTEGRAL Galactic bulge monitoring programme. To study the evolution of the source X-ray flux and spectral properties…
X-ray observations with the ROSAT High Resolution Imager (HRI) often have spatial smearing on the order of 10 arcsec (Morse 1994). This degradation of the intrinsic resolution of the instrument (5 arcsec) can be attributed to errors in the…
BAT and XRT observations of two recent well-covered GRBs observed by Swift, GRB 050315 and GRB 050319, show clearly a prompt component joining the onset of the afterglow emission. By fitting a power law form to the gamma-ray spectrum, we…
We present Swift-UVOT data on the optical afterglow of the X-ray flash of 2005 April 6 (XRF 050406) from 88s to \sim 10^5s after the initial prompt gamma-ray emission. Our observations in the V, B and U bands are the earliest that have been…
We describe a long-term Swift monitoring program of Fermi gamma-ray sources, particularly the 23 gamma-ray "sources of interest." We present a systematic analysis of the Swift X-ray Telescope light curves and hardness ratios of these…
We have performed a systematic study of Gamma-Ray Bursts (GRBs), which have various values in the peak energy of the ${\nu}F_{\nu}$ spectrum of the prompt emission, $E_{{\rm peak}}$, observed by \textsl{Swift}/BAT and \textsl{Fermi}/GBM,…
The successful operation of dedicated detectors has brought us valuable information for understanding the central engine and the progenitor of gamma-ray bursts (GRBs). For instance, the giant X-ray and optical bumps found in some…
Swift J2218.4+1925, a hard X-ray source detected by Swift BAT, has been proposed as a candidate magnetic cataclysmic variable of the polar type from optical spectroscopy. Using XMM-Newton we perform detailed timing and spectral analysis…
We compute the probability to detect long Gamma Ray Bursts (GRBs) at z>5 with Swift, assuming that GRBs form preferentially in low-metallicity environments. The model fits well both the observed BATSE and Swift GRB differential peak flux…
We present the Living Swift-XRT Point Source catalogue (LSXPS) and real-time transient detector. This system allows us for the first time to carry out low-latency searches for new transient X-ray events fainter than those available to the…
One of the major achievements of Swift is the discovery of the erratic X-ray flares harboring nearly half of gamma-ray bursts (GRBs), both for long-duration and short-duration categories, and both for traditional hard GRBs and soft X-ray…
Analyzing light curves of a complete sample of bright Swift long gamma-ray bursts (LGRBs) of which the peak photon fluxes constructed with the bin width of 1 second in the Swift 15-350 keV energy band exceed 2.6 photons cm$^{-2}$s$^{-1}$,…
The canonical observation mode for IACT gamma-ray observations employs four discrete pointings in the cardinal directions (the "wobble" mode). For the VERITAS Observatory, the target source is offset by 0.5-0.7 degrees from the camera…