A5037496050- Gamma-ray bursts and supernovae
- Stellar, planetary, and galactic studies
- Astrophysical Phenomena and Observations
- SAS software applications and methods
- Astronomical Observations and Instrumentation
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Pulsars and Gravitational Waves Research
- Statistical and numerical algorithms
- Astrophysics and Cosmic Phenomena
- Advanced X-ray and CT Imaging
- Inertial Sensor and Navigation
- Nuclear Physics and Applications
- Particle Detector Development and Performance
- Medical Imaging Techniques and Applications
- CCD and CMOS Imaging Sensors
- Approximation Theory and Sequence Spaces
- Adaptive optics and wavefront sensing
- Mathematical functions and polynomials
- Calibration and Measurement Techniques
- Advanced Numerical Analysis Techniques
- Geophysics and Sensor Technology
- Shoulder Injury and Treatment
- Nonlinear Differential Equations Analysis
- Animal Virus Infections Studies
University of Copenhagen
1998-2023
Leibniz Institute for Astrophysics Potsdam
2006
University College Copenhagen
1994
European Southern Observatory
1982-1987
We present B-, V-, RC-, IC-, J-, H-, K-, and K'-band observations of the optical transient (OT) associated with GRB 970228, based on a reanalysis previously used images unpublished data. In order to minimize calibration differences, we have collected analyzed most photometry consistently determined magnitude OT relative set secondary field stars. confirm our earlier finding that early decay light curves (before 1997 March 6) was faster than at intermediate times (between 6 April 7). At late...
We report on the results of a search for Ly-alpha emission from host galaxy z=2.140 GRB 011211 and other galaxies in its surrounding field. detect as well six The restframe equivalent width line is about 21 AA. This fifth detection out five possible detections galaxies, strongly indicating that hosts, at least high redshifts, are emitters. intriguing only 25% Lyman-Break selected similar redshifts have lines with larger than 20 Possible explanations i) preference progenitors to be metal-poor...
We present the discovery of optical transient long-duration gamma-ray burst GRB 000630. The was detected with Nordic Optical Telescope 21.1 hours after burst. At time magnitude . displayed a power-law decline characterized by decay slope A deep image obtained 25 days shows no indication contribution from supernova or host galaxy at position transient. closest is 2.0 arcsec north magnitudes afterglows 980329, 980613 and 000630 were all less than 24 epoch. discuss implications this for our...
We describe the INTEGRAL Burst Alert System (IBAS): automatic software for rapid distribution of coordinates Gamma-Ray Bursts detected by INTEGRAL. IBAS is implemented as a ground based system, working on near-real time telemetry stream. During first six months operations, GRB have been in field view instruments and localized IBAS. Positions with an accuracy few arcminutes are currently distributed to community follow-up observations within tens seconds event.
We present Ulysses and NEAR data from the detection of short or intermediate duration (2 s) gamma-ray burst GRB 000301C (2000 March 1.41 UT). The (GRB) was localised by Inter Planetary Network (IPN) RXTE to an area ~50 arcmin2. A fading optical counterpart subsequently discovered with Nordic Optical Telescope (NOT) about 42 h after burst. lies at border between long-soft short-hard classes GRBs. If belongs latter class, this would be first afterglow a UBRI photometry time discovery until 11...
The gamma-ray burst GRB000210 had the highest peak flux of any event localized by BeppoSAX as yet but it did not have a detected optical afterglow. It is therefore one events recently classified dark GRBs or GHOST (GRB Hiding Optical Source Transient), whose origin still unclear. Chandra observations allowed us to localize this GRB within ~1" and radio transient was with VLA. We identify likely (P=0.01) host galaxy at z=0.846. X-ray spectrum afterglow shows intrinsic absorption N_H=5x10**21...
Observations of the extraordinarily bright optical afterglow (OA) GRB 991208 started 2.1 d after event. The flux decay constant OA in R-band is -2.30 +/- 0.07 up to 5 d, which very likely due jet effect, and that it followed by a much steeper with -3.2 0.2, fastest one ever seen OA. A negative detection several all-sky films taken simultaneously event implies either previous additional break prior 2 occurrence (as expected from effect). existence second might indicate steepening electron...
We present optical and near-infrared follow-up observations of the X-Ray Flash (XRF) July 23 2003. Our in R-band cover temporal range from 4.2 h to 64 days after high energy event. also results multicolor imaging extending K-band on three epochs. The lightcurve afterglow first week burst is similar for long duration Gamma-Ray Bursts (GRBs), i.e., a broken power-law with late time slope alpha=-2.0 (F_nu propto t^alpha). Furthermore, spectral distribution (SED) has nu^beta) shape beta=-1.0....
We report on a 3600 s spectrum of GRB 021004 obtained with the Nordic Optical Telecope La Palma 10.71 hours after burst. identify absorption lines from five systems at redshifts 1.3806, 1.6039, 2.2983, 2.3230, and 2.3292. In addition we find an emission line which, if due to Lyα host galaxy, gives redshift 2.3351. The nearest absorber is blueshifted by 530 km s-1 respect this line, consistent shifts seen in Damped Lyman-Break galaxies similar redshifts. flux erg cm-2. Some are “line-locked”,...
Optical Transients from gamma-ray burst sources, in addition to offering a distance determination, convey important information about the physics of emission mechanism, and perhaps also underlying energy source. As phenomenon is extremely diverse, with timescales spanning several orders magnitude, some diversity optical counterpart signatures appears plausible.
We report on photometric, spectroscopic and polarimetric monitoring of the optical near-infrared (NIR) afterglow GRB020405. Ground-based observations, performed with 8 different telescopes, started about 1 day after high-energy prompt event spanned a period ~10 days; addition archival HST data extended coverage up to ~150 days GRB. first detection in NIR bands. The Balmer oxygen emission lines spectrum host galaxy indicates that GRB is located at redshift . Fe ii Mg absorption systems are...
We report on the results of deep narrow-band Lyα and broad-band U I imaging fields two Gamma-Ray bursts at redshift (GRB 000301C GRB 000926). find that host galaxy 000926 is an extended (more than 2 arcsec), strong emitter with a rest-frame equivalent width 71 Å. The consists main components several fainter knots. occurred in western component, whereas most luminosity (about 65%) originates eastern component. Using archival HST images we measure spectral slopes () to (east) (west). This...
We analyse the distribution of matter around progenitor star gamma-ray burst GRB 021004 as well properties its host galaxy with high-resolution echelle near-infrared spectroscopy. Observations were taken by 8.2m Very Large Telescope Ultraviolet and Visual Echelle spectrograph (UVES) Infrared Spectrometer And Array Camera (ISAAC) between 10 14 hours after onset event. report first detection emission lines from a in near-infrared, detecting H-alpha [O III] doublet. These allow an independent...
We present UBVRIZJsHKs broad band photometry of the host galaxy dark gamma-ray burst (GRB) February 10, 2000. These observations represent most exhaustive given to date any GRB galaxy. A grid spectral templates have been fitted Spectral Energy Distribution (SED) host. The derived photometric redshift is , which in excellent agreement with spectroscopic () proposed by Piro et al. ([CITE]) based on a single emission line. Furthermore, we determined all galaxies an area around galaxy, order...
We report on Hubble Space Telescope observations of the optical transient (OT) discovered in error box gamma-ray burst GRB 970508. The object was imaged 1997 June 2 with Imaging Spectrograph and Near-Infrared Camera Multiobject Spectrometer. reveal a pointlike source R = 23.1±0.2 H 20.6±0.3, agreement power-law temporal decay seen ground-based monitoring. Unlike case 970228, no nebulosity is detected surrounding OT set very conservative upper limits R~24.5 H~22.2 brightness any underlying...
We present polarimetric observations of the afterglow gamma-ray burst (GRB) 021004, obtained with Nordic Optical Telescope (NOT) and Very Large (VLT) between 8 17 hours after burst.Comparison among shows a 45 degree change in position angle from 9 to 16 burst, comparison published data later epochs even 90 89 burst.The linear polarization marginal change, but is also consistent being constant time.In context currently available models for changes GRBs, homogeneous jet an early break time t b...
We present ground-based and Hubble Space Telescope optical observations of the X-ray flash (XRF) 020903, covering 300 days. The afterglow showed a very rapid rise in first day, followed by relatively slow decay next few There was clear bump light curve after ~25 days, accompanied drastic change spectral energy distribution. distribution are naturally interpreted as emergence -- subsequent supernova (SN), similar to SN 1998bw. At peak luminosity, is estimated be 0.8 +/- 0.1 mag fainter than...
We present extensive multi-colour (UBVR_CI_C) photometry of the optical afterglow GRB 980519. Upon discovery, 8.3 hours after burst, source was decaying as a power law, (t-t_GRB)^alpha, with rapid decay rate alpha_1 = - 1.73+-0.04. About 13 burst steepening light-curve to alpha_2 -2.22+-0.04 observed. Within framework current models, we argue that initial decline, `break' in light curve, and spectral properties are best interpreted being due collimated ultra-relativistic jet fixed opening...
We present optical, near-infrared, and X-ray observations of the optical afterglow (OA) rich, long-duration gamma-ray burst GRB 011211. Hubble Space Telescope (HST) data obtained 14, 26, 32, 59 days after burst, show host galaxy to have a morphology that is fairly typical blue galaxies at high redshift. measure its magnitude be . detect break in OA R-band light curve which naturally accounted for by collimated outflow geometry. By fitting broken power-law we find best fit with pre-break...
We present deep HST/STIS and ground-based photometry of the host galaxy gamma-ray burst GRB 980703 taken 17, 551, 710, 716 days after burst. find that is a blue, slightly over-luminous with V_gal = 23.00 +/- 0.10, (V-R)_gal 0.43 0.13, centre approximately 0.2 mag bluer than outer regions galaxy. The has star-formation rate 8-13 M_sun/yr, assuming no extinction in host. best fit by Sersic R^(1/n) profile n ~= 1.0 half-light radius 0.13 arcsec (= 0.72/h_100 proper kpc). This corresponds to an...
We report on multi-band () observations of the host galaxy April 18, 2000 gamma-ray burst. The Spectral Energy Distribution (SED) is analysed by fitting empirical and synthetic spectral templates. find that: (i) best SED fit obtained with a starburst template, (ii) photometric redshift consistent spectroscopic redshift, (iii) colours are inconsistent an old stellar population, (iv) global extinction constrained to be in range –0.61 mag. derived agrees one reported for afterglow (–0.9 mag),...
We present the results of an optical and near-infrared (NIR) monitoring campaign counterpart Gamma-Ray Burst (GRB) 000911, located at redshift z=1.06, from 5 days to more than 13 months after explosion. Our extensive dataset is a factor 2 larger spans time interval about 4 times longer ones considered previously for this GRB afterglow; allows thorough analysis its light curve host galaxy properties. The afterglow curves show single power-law temporal decline, modified late by with moderate...
view Abstract Citations (52) References (22) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Optical candidates for the 1978 november 19 gamma-ray burst source. Pedersen, H. ; Motch, C. Tarenghi, M. Danziger, J. Pizzichini, G. Lewin, W. The authors report on detection and variability of two very faint (mR ≡ 24) objects in 4arcsec×16arcsec error region 1928 November 17 optical transient that may be associated with They discuss consequences if one these is...
We imaged the X-ray error box of GRB 980703, beginning 22.5 hours after gamma--ray event, in both optical R and near-infrared H bands. A fading optical/IR object was detected within box, coincident with variable radio source reported by Frail et al. (1998a), who also transient independently us. Further imagery revealed host galaxy, = 22.49 +/- 0.04 20.5 0.25, brightest so far detected. When excluding its contribution to total flux, H-band light curves are well-fit a power-law decay index...