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Discovery of an Afterglow Extension of the Prompt Phase of Two Gamma Ray Bursts Observed by Swift
S. D. Barthelmy, J. K. Cannizzo, N. Gehrels +19
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.…
The signature of a wind reverse shock in Gamma-ray bursts afterglows
Asaf Pe'er, Ralph A. M. J. Wijers
Explosions of massive stars are believed to be the source of a significant fraction of gamma-ray bursts (GRBs). If this is indeed the case, then the explosion blast wave propagates…
Structure in the radio counterpart to the 2004 Dec 27 giant flare from SGR 1806-20
R. P. Fender, T. W. B. Muxlow, M. A. Garrett +7
On Dec 27, 2004, the magnetar SGR 1806-20 underwent an enormous outburst resulting in the formation of an expanding, moving, and fading radio source. We report observations of this…
Thermal neutrinos from hot GRB fireballs
Hylke B. J. Koers, Ralph A. M. J. Wijers
We consider the physics of neutrinos in a fireball, i.e. a tightly coupled plasma of photons, positrons and electrons. Such a fireball is believed to form in the first stages of a…
Low-resolution VLT spectroscopy of GRBs 991216, 011211 and 021211
P. M. Vreeswijk, A. Smette, A. S. Fruchter +16
We present low-resolution VLT spectroscopy of the afterglow of the gamma-ray bursts (GRBs) 991216, 011211 and 021211. Our spectrum of GRB991216 is the only optical spectrum for thi…
Gas and dust properties in the afterglow spectra of GRB 050730
R. L. C. Starling, P. M. Vreeswijk, S. L. Ellison +9
We present early WHT ISIS optical spectroscopy of the afterglow of gamma-ray burst GRB 050730. The spectrum shows a DLA system with the highest measured hydrogen column to date: N(…
The radio afterglow of GRB 030329 at centimeter wavelengths: evidence for a structured jet or non-relativistic expansion
A. J. van der Horst, E. Rol, R. A. M. J. Wijers +3
We present our centimeter wavelength (1.4, 2.3 and 4.8 GHz) light curves of the afterglow of GRB 030329, which were obtained with the Westerbork Synthesis Radio Telescope. Modeling…
Broadband modeling of gamma-ray burst afterglows
A. J. van der Horst, R. A. M. J. Wijers, E. Rol
According to the fireball model gamma-ray burst (GRB) afterglows are the result of a shock pushed into the surrounding medium by an extremely relativistic outflow from the GRB. By…
GRB 050509B: Constraints on short gamma-ray burst models
J. Hjorth, J. Sollerman, J. Gorosabel +19
We have obtained deep optical images with the Very Large Telescope at ESO of the first well-localized short-duration gamma-ray burst, GRB 050509B. From V and R imaging, initiated ~…
On the stellar luminosity of the universe
Ralph A. M. J. Wijers
It has been noted at times that the rate of energy release in the most violent explosive events in the Universe, such as supernovae and gamma-ray bursts, rivals the stellar luminos…
The effect of neutrinos on the initial fireballs in gamma-ray bursts
Hylke B. J. Koers, Ralph A. M. J. Wijers
We investigate the fate of very compact, sudden energy depositions that may lie at the origin of gamma-ray bursts. Following on from the work of Cavallo and Rees (1978), we take ac…
The redshift distribution of gamma-ray bursts revisited
Priyamvada Natarajan, Badr Albanna, Jens Hjorth +3
In this letter, we calculate the redshift distribution of gamma-ray bursts assuming that they trace (i) the globally averaged star formation rate or (ii) the average metallicity in…
Late-epoch optical and near-infrared observations of the GRB000911 afterglow and its host galaxy
N. Masetti, E. Palazzi, E. Pian +28
We present the results of an optical and near-infrared (NIR) monitoring campaign of the counterpart of Gamma-Ray Burst (GRB) 000911, located at redshift z=1.06, from 5 days to more…
The Growth, Polarization, and Motion of the Radio Afterglow from the Giant Flare from SGR 1806-20
G. B. Taylor, J. D. Gelfand, B. M. Gaensler +8
The extraordinary giant flare (GF) of 2004 December 27 from the soft gamma repeater (SGR) 1806-20 was followed by a bright radio afterglow. We present an analysis of VLA observatio…
SCUBA sub-millimeter observations of gamma-ray bursters IV. GRB 021004, 021211, 030115, 030226, 041006
I. A. Smith, R. P. J. Tilanus, N. Tanvir +7
We discuss our ongoing program of Target of Opportunity (ToO) sub-millimeter observations of gamma-ray bursts (GRBs) using the Sub-millimetre Common-User Bolometer Array (SCUBA) on…
SCUBA sub-millimeter observations of gamma-ray bursters III. GRB 030329: The brightest sub-millimeter afterglow to date
I. A. Smith, R. P. J. Tilanus, N. Tanvir +4
We discuss our ongoing program of Target of Opportunity (ToO) sub-millimeter observations of gamma-ray bursts (GRBs) using the Sub-millimetre Common-User Bolometer Array (SCUBA) on…
Gamma-Ray Observations of a Giant Flare from The Magnetar SGR 1806-20
D. M. Palmer, S. Barthelmy, N. Gehrels +25
Magnetars comprise two classes of rotating neutron stars (Soft Gamma Repeaters (SGRs) and Anomalous X-ray Pulsars), whose X-ray emission is powered by an ultrastrong magnetic field…
A Re-brightening of the Radio Nebula associated with the 2004 December 27 giant flare from SGR 1806--20
J. D. Gelfand, Y. E. Lyubarsky, D. Eichler +7
The 2004 Dec. 27 giant Gamma-ray flare detected from the magnetar SGR 1806-20 created an expanding radio nebula which we have monitored with the Australia Telescope Compact Array a…
Diagnosing the outflow from the SGR 1806-20 Giant Flare with Radio Observations
J. Granot, E. Ramirez-Ruiz, G. B. Taylor +6
On 2004 Dec. 27, the soft gamma repeater (SGR) 1806-20 emitted the brightest giant flare (GF) ever detected from an SGR, with an (isotropic) energy release times greater…
An expanding radio nebula produced by a giant flare from the magnetar SGR 1806-20
B. M. Gaensler, C. Kouveliotou, J. D. Gelfand +16
Soft gamma repeaters (SGRs) are "magnetars", a small class of slowly spinning neutron stars with extreme surface magnetic fields, ~10^15 gauss. On 2004 December 27, a giant flare w…
How Special Are Dark Gamma-Ray Bursts: A Diagnostic Tool
E. Rol, R. A. M. J. Wijers, C. Kouveliotou +2
We present here a comprehensive study of the optical/near-infrared (IR) upper limits for gamma-ray bursts that have an X-ray afterglow. We have extrapolated the X-ray afterglows to…
Spectroscopy of GRB 021004: a structured jet ploughing through a massive stellar wind
R. L. C. Starling, R. A. M. J. Wijers, M. A. Hughes +4
We present spectra of the afterglow of GRB 021004 taken with WHT ISIS and VLT FORS1 at three epochs spanning 0.49--6.62 days after the burst. We observe strong absorption likely co…