Related papers: Is the Fuzziness of GRB970228 constant?
We report on observations of the fading optical counterpart of the gamma-ray burst GRB 970228, made on 4~September~1997 using the STIS CCD on the Hubble Space Telescope. The unresolved counterpart is detected at V=28 +/- 0.25, consistent…
GRB 970228 is the first gamma ray burst for which prolonged post-burst transient x-ray, optical, and infrared emission has been detected. Recent Hubble Space Telescope observations show that the transient consists of two components: a point…
Although more than 2,000 astronomical gamma-ray bursts (GRBs) have been detected, and numerous models proposed to explain their occurrence, they have remained enigmatic owing to the lack of an obvious counterpart at other wavelengths. The…
We carefully analyze the WFPC2 and STIS images of GRB970228. We measure magnitudes for the GRB970228 point source component in the WFPC2 images of $V=26.20^{+0.14}_{-0.13}$, $I_c=23.94^{+0.10}_{-0.09}$ and $V=26.52^{+0.16}_{-0.18}$,…
After a quarter of a century of gamma-ray burst (GRB) astronomy, the Italian-Dutch satellite BeppoSAX on Feb 28th, 1997 detected a soft X-ray afterglow from GRB 970228 and positioned it accurately. This made possible the successful…
The IRAS 100 micron image of the GRB 970228 field shows that the amount of galactic dust in this direction is substantial and varies on arcminute angular scales. From an analysis of the observed surface density of galaxies in the $2.6'…
The analysis of the light curves of the optical counterparts of GRB 970228 and GRB 970508 points out remarkable similarities. The spectral distribution obtained from the color indices shows that both the transients became bluer during the…
We report on observations of the fading optical counterpart of the gamma-ray burst GRB 970228, made with the Hubble Space Telescope STIS CCD approximately six months after outburst and with the HST/NICMOS and Keck/NIRC approximately one…
We present B-, V-, R_c-, I_c-, J-, H-, K- and K'-band observations of the optical transient (OT) associated with GRB970228, based on a reanalysis of previously used images and unpublished data. In order to minimize calibration differences…
The gamma-ray burst source GRB970228 has been observed after a delay of 8--12 hours in X-rays and after one day in visible and near infrared light. This marks the first detection of emission at lower frequencies following the gamma-ray…
We investigate whether current data on the distribution of observed flux densities of Fast Radio Bursts (FRBs) are consistent with a constant source density in Euclidean space. We use the number of FRBs detected in two surveys with…
We present the results of photometric observations of the variable optical source associated to the remnant of the gamma-ray burst GRB970508 performed at SAO RAS (Russia) from May to August 1997. The observations were carried out with the…
The gamma-ray burst of 28 February 1997 (GRB 970228) ushered in the discovery of the afterglow phenomenon. Despite intense study of the host galaxy, however, the nature of the host and the distance to the burst eluded the community. Here we…
We present the R_c band light curve of the optical transient (OT) associated with GRB970228, based on re-evaluation of existing photometry. Data obtained until April 1997 suggested a slowing down of the decay of the optical brightness.…
We report on observations of the field of GRB~970508 made in early August 1998, 454 days after outburst, with the STIS CCD camera onboard the Hubble Space Telescope. The images, taken in open filter (50CCD) mode, clearly reveal the presence…
We present the R and V light curves of the optical counterpart of GRB 970228. A critical analysis of all the available data is made in light of the results achieved in the recent GRB Symposium held in Huntsville and by considering the…
The 18 mag QSO 1633+382 (4C38.41, z=1.807) showed a very pronounced outburst in 2001/2002. With a peak amplitude of more than 9 Jy at 90GHz, this flare was brighter than any known previous flare in this source (data available since…
The deviation from the power-law decline of the optical flux observed in GRB 970228 and GRB 980326 has been used recently to argue in favor of the connection between GRBs and supernovae. We consider an alternative explanation for this…
The observations with the SAO-RAS 6-m telescope in July-August 1998 show that the GRB970508 optical remnant has varied very little since November 1997. We can conclude that we observe a proper host galaxy without the GRB optical remnant.…
Visible afterglow counterparts have now been detected for two GRBs (970228 and 970508) but are absent, with $L_{opt}/L_{\gamma}$ ratios at least two orders of magnitude lower, for other GRBs, e.g., 970828. The causes of this variation are…