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Photometry and spectroscopy of GRB 060526: A detailed study of the afterglow and host galaxy of a z=3.2 gamma-ray burst
C. C. Thöne, D. A. Kann, G. Jóhannesson +58
Aims: With this paper we want to investigate the highly variable afterglow light curve and environment of gamma-ray burst (GRB) 060526 at . Methods: We present one of the…
Early spectroscopic identification of SN 2008D
D. Malesani, J. P. U. Fynbo, J. Hjorth +27
SN 2008D was discovered while following up an unusually bright X-ray transient in the nearby spiral galaxy NGC 2770. We present early optical spectra (obtained 1.75 days after the…
The extreme, red afterglow of GRB 060923A: Distance or dust?
N. R. Tanvir, A. J. Levan, E. Rol +16
Gamma-ray bursts are powerful probes of the early universe, but locating and identifying very distant GRBs remains challenging. We report here the discovery of the K-band afterglow…
GRB 070306: A Highly Extinguished Afterglow
A. O. Jaunsen, E. Rol, D. J. Watson +12
We report on the highly extinguished afterglow of GRB 070306 and the properties of the host galaxy. An optical afterglow was not detected at the location of the burst, but in near-…
GRB051022: physical parameters and extinction of a prototype dark burst
Evert Rol, Alexander van der Horst, Klaas Wiersema +19
GRB051022 was undetected to deep limits in early optical observations, but precise astrometry from radio and X-ray showed that it most likely originated in a galaxy at z~0.8. We re…
Gamma-ray burst host galaxies and the link to star-formation
J. P. U. Fynbo, J. Hjorth, D. Malesani +5
We briefly review the current status of the study of long-duration gamma-ray burst (GRB) host galaxies. GRB host galaxies are mainly interesting to study for two reasons: 1) they m…
A Search for Host Galaxies of 24 Gamma-Ray Bursts
J. -E. Ovaldsen, A. O. Jaunsen, J. P. U. Fynbo +6
We report the results from observations of 24 gamma ray burst (GRB) fields from 2005 and 2006 undertaken at the Danish 1.54m telescope at ESO/La Silla. Photometry and positions for…
The nature of the X-Ray Flash of August 24 2005
J. Sollerman, J. P. U. Fynbo, J. Gorosabel +23
We present comprehensive photometric R-band observations of the fading optical afterglow of the X-Ray Flash XRF050824, from 11 minutes to 104 days after the burst. The R-band light…
Fundamental Properties of GRB-Selected Galaxies: A Swift/VLT Legacy Survey
P. Jakobsson, J. Hjorth, J. P. U. Fynbo +2
We present the motivation, aims and preliminary result from the Swift/VLT legacy survey on gamma-ray burst host galaxies. This survey will produce a homogeneous and well-understood…
Three intervening galaxy absorbers towards GRB060418: faint and dusty?
Sara L. Ellison, Paul Vreeswijk, Cedric Ledoux +8
We present an analysis of three strong, intervening Mg II absorption systems (z_abs = 0.603, 0.656, 1.107) towards the optical afterglow of gamma-ray burst (GRB) 060418. From high…
Supernova 2006aj and the associated X-Ray Flash 060218
J. Sollerman, A. O. Jaunsen, J. P. U. Fynbo +23
We have studied the afterglow of the gamma-ray burst (GRB) of February 18, 2006. This is a nearby long GRB, with a very low peak energy, and is therefore classified as an X-ray Fla…
Discovery of a high-redshift Einstein ring
R. A. Cabanac, D. Valls-Gabaud, A. O. Jaunsen +2
We report the discovery of a partial Einstein ring of radius 1.48arcsec produced by a massive (and seemingly isolated) elliptical galaxy. The spectroscopic follow-up at the VLT rev…
The blue host galaxy of the red GRB 000418
J. Gorosabel, S. Klose, L. Christensen +25
We report on multi-band (UBVRIZJsKs) observations of the host galaxy of the April 18, 2000 gamma-ray burst. The Spectral Energy Distribution (SED) is analysed by fitting empirical…
The optical/near-IR spectral energy distribution of the GRB 000210 host galaxy
J. Gorosabel, L. Christensen, J. Hjorth +25
We report on UBVRIZJsHKs-band photometry of the dark GRB 000210 host galaxy. Fitting a grid of spectral templates to its Spectral Energy Distribution (SED), we derived a photometri…
Time delay and lens redshift for the doubly imaged BAL quasar SBS1520+530
I. Burud, J. Hjorth, F. Courbin +6
We present optical R-band light curves of the gravitationally lensed quasar SBS1520+530 derived from data obtained at the Nordic Optical Telescope. A time delay of 130+/-3 days (1…
The afterglow and complex environment of the optically dim burst GRB 980613
Jens Hjorth, Bjarne Thomsen, Svend R. Nielsen +15
We report the identification of the optical afterglow of GRB 980613 in R- and I-band images obtained between 16 and 48 hours after the gamma-ray burst. Early near-infrared (NIR) H…
The time delay of the quadruple quasar RX J0911.4+0551
Jens Hjorth, Ingunn Burud, Andreas O. Jaunsen +9
We present optical lightcurves of the gravitationally lensed components A (=A1+A2+A3) and B of the quadruple quasar RX J0911.4+0551 (z = 2.80). The observations were primarily obta…
An HST study of three very faint GRB host galaxies
A. O. Jaunsen, M. I. Andersen, J. Hjorth +8
As part of the HST/STIS GRB host survey program we present the detection of three faint gamma-ray burst (GRB) host galaxies based on an accurate localisation using ground-based dat…
Constraining halo properties from galaxy-galaxy lensing and photo-z
Andreas O. Jaunsen
Here we present results from a maximum likelihood analysis of galaxy-galaxy weak lensing effects as measured in a 12.5' x 12.5' field obtained at the Nordic Optical Telescope, on L…
Optical observations of the dark Gamma-Ray Burst GRB 000210
Javier Gorosabel, Jens Hjorth, Holger Pedersen +11
We report on optical observations on GRB 000210 obtained with the 2.56-m Nordic Optical Telescope and the 1.54-m Danish Telescope starting 12.4 hours after the gamma-ray event. The…
The Host Galaxy and Optical Light Curve of the Gamma-Ray Burst GRB 980703
S. Holland, J. P. U. Fynbo, J. Hjorth +10
We present deep HST/STIS and ground-based photometry of the host galaxy of the gamma-ray burst GRB 980703 taken 17, 551, 710, and 716 days after the burst. We find that the host is…
VLT identification of the optical afterglow of the gamma-ray burst GRB 000131 at z=4.50
M. I. Andersen, J. Hjorth, H. Pedersen +16
We report the discovery of the gamma-ray burst GRB 000131 and its optical afterglow. The optical identification was made with the VLT 84 hours after the burst following a BATSE det…
Depletion of background galaxies due to the cluster lens CL0024+1654: U and R band observations
O. E. Rognvaldsson, T. R. Greve, J. Hjorth +7
We have obtained U and R band observations of the depletion of background galaxies due to the gravitational lensing of the galaxy cluster CL0024+1654 (z=0.39). The radial depletion…
HST/STIS Imaging of the Host Galaxy of GRB980425/SN1998bw
J. U. Fynbo, S. Holland, M. I. Andersen +6
We present HST/STIS observations of ESO 184-G82, the host galaxy of the gamma-ray burst GRB 980425 associated with the peculiar Type Ic supernova SN1998bw. ESO 184-G82 is found to…