scholarly journals A statistical method to detect non-stationarities of gamma-ray burst jets

2019 ◽  
Author(s):  
A Budai ◽  
P Raffai ◽  
B Borgulya ◽  
B A Dawes ◽  
G Szeifert ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Light Curves ◽  
Prompt Gamma ◽  
Density Profiles ◽  
Gamma Ray Burst ◽  
Gaussian Profile ◽  
Angle Measurements ◽  
Restoring Forces ◽  
Break Time ◽  
Characteristic Angle

Abstract We propose a method to detect possible non-stationarities of gamma-ray burst jets. Assuming that the dominant source of variability in the prompt gamma light curve is the non-stationarity of the jet, we show that there should be a connection between the variability measure and the characteristic angle of the jet derived from the jet break time of the afterglow. We carried out Monte Carlo simulations of long gamma-ray burst observations assuming three radial luminosity density profiles for jets and randomizing all burst parameters, and created samples of gamma light curves by simulating jets undergoing Brownian motions with linear restoring forces. We were able to demonstrate that the connection between the variability and the characteristic angle is an anti-correlation in case of uniform and power-law jet profiles, and a correlation in case of a Gaussian profile. We have found that as low as 50 (144) gamma-ray burst observations with jet angle measurements can be sufficient for a 3σ (5σ) detection of the connection. The number of observations required for the detection depends on the underlying jet beam profile, ranging from 50 (144) to 237 (659) for the four specific profile models we tested.

scholarly journals A study of gamma-ray burst afterglows as they first come into view of the SwiftUltraviolet and Optical Telescope

2019 ◽  
Vol 488 (2) ◽  
pp. 2855-2863
Author(s):  
M J Page ◽  
S R Oates ◽  
M De Pasquale ◽  
A A Breeveld ◽  
S W K Emery ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Light Curves ◽  
Field Of View ◽  
Prompt Gamma ◽  
Optical Telescope ◽  
Gamma Ray Burst ◽  
Thick Shells ◽  
Temporal Indices ◽  
Rule Out

ABSTRACT We examine the emission from optically bright gamma-ray burst (GRB) afterglows, as the Ultraviolet and Optical Telescope (UVOT) on the Neil Gehrels Swift Observatory first begins observing, following the slew to target the GRB, while the pointing of the Swift satellite is still settling. We verify the photometric quality of the UVOT settling data using bright stars in the field of view. In the majority of cases, we find no problems with the settling exposure photometry, but in one case, we excise the first second of the exposure to mitigate a spacecraft attitude reconstruction issue, and in a second case, we exclude the first second of the exposure in which the UVOT photocathode voltage appears to be ramping up. Of a sample of 23 afterglows which have peak V magnitudes <16, we find that all are detected in the settling exposures, when Swift arrives on target. For nine of the GRBs, the UVOT settling exposure took place before the conclusion of the prompt gamma-ray emission. Five of these GRBs have well-defined optical peaks after the settling exposures, with rises of >0.5 mag in their optical light curves, and there is a marginal trend for these GRBs to have long T90. Such a trend is expected for thick-shell afterglows, but the temporal indices of the optical rises and the timing of the optical peaks appear to rule out thick shells.

scholarly journals Gamma‐Ray Burst Afterglow: Polarization and Analytic Light Curves

1999 ◽  
Vol 511 (2) ◽  
pp. 852-861 ◽  
Author(s):  
Andrei Gruzinov ◽  
Eli Waxman
Keyword(s):  
Gamma Ray ◽  
Light Curves ◽  
Gamma Ray Burst

scholarly journals Are the missing X-ray breaks in gamma-ray burst afterglow light curves merely hidden?

2008 ◽  
Vol 386 (2) ◽  
pp. 859-863 ◽  
Author(s):  
P. A. Curran ◽  
A. J. van der Horst ◽  
R. A. M. J. Wijers
Keyword(s):  
Gamma Ray ◽  
Light Curves ◽  
Gamma Ray Burst ◽  
X Ray

scholarly journals Imprint of Gravitational Lensing by Population III Stars in Gamma‐Ray Burst Light Curves

2006 ◽  
Vol 650 (1) ◽  
pp. 252-260 ◽  
Author(s):  
Y. Hirose ◽  
M. Umemura ◽  
A. Yonehara ◽  
J. Sato
Keyword(s):  
Gravitational Lensing ◽  
Gamma Ray ◽  
Light Curves ◽  
Gamma Ray Burst ◽  
Population Iii Stars ◽  
Population Iii

scholarly journals A comparison between short GRB afterglows and kilonova AT2017gfo: shedding light on kilonovae properties

2020 ◽  
Vol 493 (3) ◽  
pp. 3379-3397 ◽  
Author(s):  
A Rossi ◽  
G Stratta ◽  
E Maiorano ◽  
D Spighi ◽  
N Masetti ◽  
...  
Keyword(s):  
Gravitational Wave ◽  
Gamma Ray ◽  
Light Curves ◽  
Optical Counterpart ◽  
Wave Source ◽  
Gamma Ray Burst ◽  
Nir Light ◽  
First Time ◽  
Short Grbs

ABSTRACT Multimessenger astronomy received a great boost following the discovery of kilonova (KN) AT2017gfo, the optical counterpart of the gravitational wave source GW170817 associated with the short gamma-ray burst GRB 170817A. AT2017gfo was the first KN that could be extensively monitored in time using both photometry and spectroscopy. Previously, only few candidates have been observed against the glare of short GRB afterglows. In this work, we aim to search the fingerprints of AT2017gfo-like KN emissions in the optical/NIR light curves of 39 short GRBs with known redshift. For the first time, our results allow us to study separately the range of luminosity of the blue and red components of AT2017gfo-like kilonovae in short GRBs. In particular, the red component is similar in luminosity to AT2017gfo, while the blue KN can be more than 10 times brighter. Finally, we exclude a KN as luminous as AT2017gfo in GRBs 050509B and 061201.

scholarly journals GAMMA-RAY BURST LIGHT CURVES IN THE RELATIVISTIC TURBULENCE AND RELATIVISTIC SUBJET MODELS

2009 ◽  
Vol 695 (1) ◽  
pp. L10-L14 ◽  
Author(s):  
Ayah Lazar ◽  
Ehud Nakar ◽  
Tsvi Piran
Keyword(s):  
Gamma Ray ◽  
Light Curves ◽  
Gamma Ray Burst
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