12 research outputs found
A two-component jet model for the optical plateau in the afterglow of GRB 191221B
The long gamma-ray burst GRB 191221B has abundant observations in X-ray,
optical and radio bands. In the literature, the observed optical light curve of
GRB 191221B displays a plateau around 0.1-day, which is rather peculiar in
gamma-ray bursts. Here we performed detailed analysis of the observational data
from Swift/UVOT, VLT and LCO, obtained the light curve of the multi-band
afterglow of GRB 191221B. By examining optical, ultraviolet, X-ray, and radio
data for this event, we demonstrate that an on-axis two-component jet model can
explain the observations. Our analysis suggests that the narrow component has
an initial Lorentz factor of 400 and a jet opening half-angle of ,
while the wide component has an initial Lorentz factor of 25 and a jet opening
half-angle of . The narrow jet dominates the early decay, whereas
the wider jet causes the optical plateau and dominates late decay. According to
this model, the reason for the absence of the X-ray plateau is due to the
steeper spectral index of the wide component, resulting in a less significant
flux contribution from the wide jet in the X-ray bands than in the optical
bands. Moreover, we have explained the inconsistency in the decay indices of
the UVOT and Rc-band data around 2000 seconds using reverse shock emission.Comment: 10 pages, 7 figures, Accepted by the Monthly Notices of the Royal
Astronomical Societ
MASTER prompt and follow-up GRB observations
There are the results of gamma-ray bursts observations obtained using the
MASTER robotic telescope in 2007 - 2009. We observed 20 error-boxes of
gamma-ray bursts this period.The limits on their optical brightnesses have been
derived. There are 5 prompt observations among them, obtained at our very wide
field cameras. Also we present the results of the earliest observations of the
optical emission of the gamma-ray bursts GRB 050824 and GRB 060926.Comment: 10 pages, 2 figure
Master Robotic Net
The main goal of the MASTER-Net project is to produce a unique fast sky
survey with all sky observed over a single night down to a limiting magnitude
of 19 - 20mag. Such a survey will make it possible to address a number of
fundamental problems: search for dark energy via the discovery and photometry
of supernovas (including SNIa), search for exoplanets, microlensing effects,
discovery of minor bodies in the Solar System and space-junk monitoring. All
MASTER telescopes can be guided by alerts, and we plan to observe prompt
optical emission from gamma-ray bursts synchronously in several filters and in
several polarization planes.Comment: 10 pages, 8 figure
Transient detections and other real-time data processing from wide-field chambers MASTER-VWF
At present time Robotic observatory making is of current importance. Having a
large field of view and being able to point at anywhere, Robotic astronomical
systems are indispensable when they looking for transients like grb, supernovae
explosions, novae etc, as it's impossible in these cases to foresee what you
should point you telescope at and when. In work are described prompt GRB
observations received on wide-field chambers MASTER-VWF, and also methods of
the images analysis and transients classifications applied in real-time data
processing in this experiment. For 7 months of operation 6 synchronous
observations of gamma-ray burst had been made by MASTER VWF in Kislovodsk and
Irkutsk. In all cases a high upper limits have been received (see tabl \ref
{tab_grbwf} and fig. \ref {allgrb}).Comment: 21 pages, 21 figure, 2 tables, Advances in Astronomy in pres
MASTER Real-Time Multi-Message Observations of High Energy Phenomena
This review considers synchronous and follow-up MASTER Global Robotic Net optical observations of high energy astrophysical phenomena such as fast radio bursts (FRB), gamma-ray bursts (including prompt optical emission polarization discovery), gravitational-wave events, detected by LIGO/VIRGO (including GW170817 and independent Kilonova discovery), high energy neutrino sources (including the detection of IC-170922A progenitor) and others. We report on the first large optical monitoring campaign of the closest at that moment radio burster FRB 180916.J0158+65 simultaneously with a radio burst. We obtained synchronous limits on the optical flux of the FRB 180916.J0158+65 and FRB 200428 (soft gamma repeater SGR 1935+2154) (The CHIME/FRB Collaboration, Nature 2020, 587) at 155093 MASTER images with the total exposure time equal to 2,705,058 s, i.e., 31.3 days. It follows from these synchronous limitations that the ratio of the energies released in the optical and radio ranges does not exceed 4 × 105. Our optical monitoring covered a total of 6 weeks. On 28 April 2020, MASTER automatically following up on a Swift alert began to observe the galactic soft gamma repeater SGR 1935+2154 experienced another flare. On the same day, radio telescopes detected a short radio burst FRB 200428 and MASTER-Tavrida telescope determined the best prompt optical limit of FRB/SGR 1935+2154. Our optical limit shows that X-ray and radio emissions are not explained by a single power-law spectrum. In the course of our observations, using special methods, we found a faint extended afterglow in the FRB 180916.J0158+65 direction associated with the extended emission of the host galaxy
MASTER Real-Time Multi-Message Observations of High Energy Phenomena
This review considers synchronous and follow-up MASTER Global Robotic Net optical observations of high energy astrophysical phenomena such as fast radio bursts (FRB), gamma-ray bursts (including prompt optical emission polarization discovery), gravitational-wave events, detected by LIGO/VIRGO (including GW170817 and independent Kilonova discovery), high energy neutrino sources (including the detection of IC-170922A progenitor) and others. We report on the first large optical monitoring campaign of the closest at that moment radio burster FRB 180916.J0158+65 simultaneously with a radio burst. We obtained synchronous limits on the optical flux of the FRB 180916.J0158+65 and FRB 200428 (soft gamma repeater SGR 1935+2154) (The CHIME/FRB Collaboration, Nature 2020, 587) at 155093 MASTER images with the total exposure time equal to 2,705,058 s, i.e., 31.3 days. It follows from these synchronous limitations that the ratio of the energies released in the optical and radio ranges does not exceed 4 × 105. Our optical monitoring covered a total of 6 weeks. On 28 April 2020, MASTER automatically following up on a Swift alert began to observe the galactic soft gamma repeater SGR 1935+2154 experienced another flare. On the same day, radio telescopes detected a short radio burst FRB 200428 and MASTER-Tavrida telescope determined the best prompt optical limit of FRB/SGR 1935+2154. Our optical limit shows that X-ray and radio emissions are not explained by a single power-law spectrum. In the course of our observations, using special methods, we found a faint extended afterglow in the FRB 180916.J0158+65 direction associated with the extended emission of the host galaxy