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The POLAR Gamma-Ray Burst Polarization Catalog
- Source :
- Astronomy and Astrophysics, Vol. 644 (2020) P. A124
- Publication Year :
- 2020
- Publisher :
- arXiv, 2020.
-
Abstract
- Despite over 50 years of research, many open questions remain about the origin and nature of GRBs. Polarization measurements of the prompt emission of these extreme phenomena have long been thought to be the key to answering a range of these questions. The POLAR detector was designed to produce the first set of detailed and reliable polarization measurements in an energy range of approximately 50-500 keV. During late 2016 and early 2017, POLAR detected a total of 55 GRBs. Analysis results of 5 of these GRBs have been reported in the past. The results were found to be consistent with a low or unpolarized flux. However, previous reports by other collaborations found high levels of polarization. We study the polarization for all the 14 GRBs observed by POLAR for which statistically robust inferences are possible. Additionally, time-resolved polarization studies are performed on GRBs with sufficient apparent flux. A publicly available polarization analysis tool, developed within the 3ML framework, was used to produce statistically robust results. The method allows to combine spectral and polarimetric data from POLAR with spectral data from the Fermi GBM and Swift-BAT to jointly model the spectral and polarimetric parameters. The time integrated analysis finds all results to be compatible with a low or zero polarization with the caveat that, when time-resolved analysis is possible within individual pulses, we observe moderate polarization with a rapidly changing polarization angle. Thus, time-integrated polarization results, while pointing to lower polarization are potentially an artifact of summing over the changing polarization signal and thus, washing out the true moderate polarization. Therefore, we caution against over interpretation of any time-integrated results and encourage one to wait for more detailed polarization measurements from forthcoming missions such as POLAR-2 and LEAP.<br />Comment: 43 pages, 78 figures, Accepted for publication in A&A
- Subjects :
- Astrophysics::High Energy Astrophysical Phenomena
Polarimetry
FOS: Physical sciences
Astrophysics
ddc:500.2
general [gamma-ray burst]
01 natural sciences
polarimeters [instrumentation]
symbols.namesake
Observatory
0103 physical sciences
data analysis [methods]
010306 general physics
010303 astronomy & astrophysics
Instrumentation and Methods for Astrophysics (astro-ph.IM)
Physics
High Energy Astrophysical Phenomena (astro-ph.HE)
polarization
Brewster's angle
Linear polarization
Astronomy and Astrophysics
Polarization (waves)
Space and Planetary Science
symbols
Polar
Gamma-ray burst
Astrophysics - High Energy Astrophysical Phenomena
Astrophysics - Instrumentation and Methods for Astrophysics
catalogs
Fermi Gamma-ray Space Telescope
Subjects
Details
- ISSN :
- 00046361
- Database :
- OpenAIRE
- Journal :
- Astronomy and Astrophysics, Vol. 644 (2020) P. A124
- Accession number :
- edsair.doi.dedup.....2b53e83640349783a7fa406970dbdf40
- Full Text :
- https://doi.org/10.48550/arxiv.2009.04871