Polarimetric Analysis of the Long Duration Gamma-Ray Burst GRB 160530A With the Balloon Borne Compton Spectrometer and Imager

Journal Article · Fri Oct 20 04:00:00 EDT 2017 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/AA8CCB· OSTI ID:22679730

Lowell, A. W.; Boggs, S. E; Chiu, C. L.; Kierans, C. A.; Sleator, C.; Tomsick, J. A.; Zoglauer, A. C. ^[1]; Chang, H. -K.; Tseng, C. -H.; Yang, C. -Y. ^[2]; Jean, P.; Ballmoos, P. von ^[3]; Lin, C. -H. ^[4]; Amman, M. ^[5]

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1. Space Sciences Laboratory, University of California, Berkeley (United States)
2. Institute of Astronomy, National Tsing Hua University, Taiwan (China)
3. IRAP Toulouse (France)
4. Institute of Physics, Academia Sinica, Taiwan (China)
5. Lawrence Berkeley National Laboratory (United States)

A long duration gamma-ray burst, GRB 160530A, was detected by the Compton Spectrometer and Imager (COSI) during the 2016 COSI Super Pressure Balloon campaign. As a Compton telescope, COSI is inherently sensitive to the polarization of gamma-ray sources in the energy range 0.2–5.0 MeV. We measured the polarization of GRB 160530A using (1) a standard method (SM) based on fitting the distribution of azimuthal scattering angles with a modulation curve and (2) an unbinned, maximum likelihood method (MLM). In both cases, the measured polarization level was below the 99% confidence minimum detectable polarization levels of 72.3% ± 0.8% (SM) and 57.5% ± 0.8% (MLM). Therefore, COSI did not detect polarized gamma-ray emission from this burst. Our most constraining 90% confidence upper limit on the polarization level was 46% (MLM).

• OSTI ID: 22679730
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 848; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COMPTON SPECTROMETERS
COSMIC GAMMA BURSTS
DISTRIBUTION
EMISSION
GAMMA SOURCES
IMAGES
MAXIMUM-LIKELIHOOD FIT
MEV RANGE
POLARIMETERS
POLARIZATION
SCATTERING
TELESCOPES