Related papers: Pile-up correction for the Swift-XRT observations …
Gamma-ray bursts (GRBs) have been detected up to GeV energies and are predicted by many models to emit in the very high energy (VHE, > 100 GeV) regime too. Detection of such emission would allow us to constrain GRB models. Since its launch,…
Since the advent of the Swift satellite it has been possible to obtain precise localisations of GRB positions of sub-arcsec accuracy within seconds, facilitating ground-based robotic telescopes to automatically slew to the target within…
The dynamic range of photon counting micro-channel-plate (MCP) intensified charged-coupled device (CCD) instruments such as the Swift Ultraviolet/Optical Telescope (UVOT) and the XMM-Newton Optical Monitor (XMM-OM) is limited at the bright…
Swift discovered GRB050128 with the Burst Alert Telescope and promptly pointed its narrow field instruments to monitor the afterglow. X-ray observations started 108 s after the trigger time. The early decay of the afterglow is relatively…
The Swift X-ray Telescope focal plane camera is a front-illuminated MOS CCD, providing a spectral response kernel of 135 eV FWHM at 5.9 keV as measured before launch. We describe the CCD calibration program based on celestial and on-board…
To date, the Burst Alert Telescope (BAT) onboard Swift has detected ~ 1000 gamma-ray bursts (GRBs), of which ~ 360 GRBs have redshift measurements, ranging from z = 0.03 to z = 9.38. We present the analyses of the BAT-detected GRBs for the…
We present results of Swift optical, UV and X-ray observations of the afterglow of GRB 050801. The source is visible over the full optical, UV and X-ray energy range of the Swift UVOT and XRT instruments.Both optical and X-ray lightcurves…
The Ultraviolet/Optical Telescope (UVOT) is one of three instruments onboard the Swift observatory. The photometric calibration has been published, and this paper follows up with details on other aspects of the calibration including a…
In collaboration with the Observatories of Palermo and Rome and the SAX-SDC we are constructing a multi-site interactive archive system featuring specific analysis tools. In this context we developed a detection algorithm based on the…
We present observations of GRB 050318 by the Ultra-Violet and Optical Telescope (UVOT) on-board the Swift observatory. The data are the first detections of a Gamma Ray Burst (GRB) afterglow decay by the UVOT instrument, launched…
There are a subset of short gamma-ray bursts (SGRBs) which exhibit a rebrightening in their high-energy light curves known as extended emission. These bursts have the potential to discern between various models proposed to describe SGRBs as…
While waiting for new gamma-ray burst detections, the Burst Alert Telescope (BAT) on board Swift covers each day ~50% of the sky in the hard X-ray band (``Survey data''). The large field of view (FOV), high sensitivity and good angular…
The Burst Alert Telescope (BAT) on board Swift has accumulated extensive light curves for 265 sources (not including GRBs) in the energy range 14 to 200 keV. We present here a summary of searches for periodic modulation in the flux from…
We propose a new method for the classification of optically dark gamma-ray bursts (GRBs), based on the X-ray and optical-to-X-ray spectral indices of GRB afterglows, and utilizing the spectral capabilities of Swift. This method depends less…
The effective bandwidth of an energy dispersive x-ray fluorescence spectroscopy system is limited by the timing of incident photons. When multiple photons strike the detector within the processing time of the detector photon pile-up occurs…
The system RX J0806.3+1527 (HM Cnc) is a pulsating X-ray source with 100 per cent modulation on a period of 321.5 s (5.4 min). This period reflects the orbital motion of a close binary consisting of two interacting white dwarfs. Here we…
We present a machine learning (ML) based method for automated detection of Gamma-Ray Burst (GRB) candidate events in the range 60 keV - 250 keV from the AstroSat Cadmium Zinc Telluride Imager data. We use density-based spatial clustering to…
We present the Swift X-ray Cluster Survey (SWXCS) catalog obtained using archival data from the X-ray telescope (XRT) on board the Swift satellite acquired from 2005 to 2012, extending the first release of the SWXCS. The catalog provides…
Gamma-ray bursts (GRBs) show diverse X-ray afterglow light-curves, including breaks and plateaus, whose physical origins remain debated. Previous claims linked high-energy ($E \ge 100$ MeV) detection to X-ray afterglow complexity or plateau…
In 2006 February, shortly after its launch, Swift began monitoring the center of the Milky Way with the onboard X-Ray Telescope using short 1-ks exposures performed every 1-4 days. Between 2006 and 2014, over 1200 observations have been…