Detection of polarized gamma-ray emission from the Crab nebula with the Hitomi Soft Gamma-ray Detector

Hitomi Collaboration

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

We present the results from the Hitomi Soft Gamma-ray Detector (SGD) observation of the Crab nebula. The main part of SGD is a Compton camera, which in addition to being a spectrometer, is capable of measuring polarization of gamma-ray photons. The Crab nebula is one of the brightest X-ray/gamma-ray sources on the sky, and the only source from which polarized X-ray photons have been detected. SGD observed the Crab nebula during the initial test observation phase of Hitomi. We performed data analysis of the SGD observation, SGD background estimation, and SGD Monte Carlo simulations and successfully detected polarized gamma-ray emission from the Crab nebula with only about 5 ks exposure time. The obtained polarization fraction of the phase-integrated Crab emission (sum of pulsar and nebula emissions) is (22.1%±10.6%), and the polarization angle is 110°.7 + 13°.2/-13°.0 in the energy range of 60.160 keV (the errors correspond to the 1 σ deviation). The confidence level of the polarization detection was 99.3%. The polarization angle measured by SGD is about one sigma deviation with the projected spin axis of the pulsar, 124°.0 ± 0°.0.1.

Original languageEnglish
Article number113
JournalPublications of the Astronomical Society of Japan
Volume70
Issue number6
DOIs
Publication statusPublished - 2018 Dec 1

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Crab nebula
crab
gamma rays
detectors
polarization
pulsars
deviation
detector
detection
crabs
photons
spectrometer
nebulae
sky
confidence
x rays
cameras
spectrometers

Keywords

  • Instrumentation: polarimeters
  • Polarization-X-rays: individual (Crab)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Detection of polarized gamma-ray emission from the Crab nebula with the Hitomi Soft Gamma-ray Detector. / Hitomi Collaboration.

In: Publications of the Astronomical Society of Japan, Vol. 70, No. 6, 113, 01.12.2018.

Research output: Contribution to journalArticle

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abstract = "We present the results from the Hitomi Soft Gamma-ray Detector (SGD) observation of the Crab nebula. The main part of SGD is a Compton camera, which in addition to being a spectrometer, is capable of measuring polarization of gamma-ray photons. The Crab nebula is one of the brightest X-ray/gamma-ray sources on the sky, and the only source from which polarized X-ray photons have been detected. SGD observed the Crab nebula during the initial test observation phase of Hitomi. We performed data analysis of the SGD observation, SGD background estimation, and SGD Monte Carlo simulations and successfully detected polarized gamma-ray emission from the Crab nebula with only about 5 ks exposure time. The obtained polarization fraction of the phase-integrated Crab emission (sum of pulsar and nebula emissions) is (22.1{\%}±10.6{\%}), and the polarization angle is 110°.7 + 13°.2/-13°.0 in the energy range of 60.160 keV (the errors correspond to the 1 σ deviation). The confidence level of the polarization detection was 99.3{\%}. The polarization angle measured by SGD is about one sigma deviation with the projected spin axis of the pulsar, 124°.0 ± 0°.0.1.",
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author = "{Hitomi Collaboration} and Felix Aharonian and Hiroki Akamatsu and Fumie Akimoto and Allen, {Steven W.} and Lorella Angelini and Marc Audard and Hisamitsu Awaki and Magnus Axelsson and Aya Bamba and Bautz, {Marshall W.} and Roger Blandford and Brenneman, {Laura W.} and Brown, {Gregory V.} and Esra Bulbul and Cackett, {Edward M.} and Maria Chernyakova and Chiao, {Meng P.} and Coppi, {Paolo S.} and Elisa Costantini and {De Plaa}, Jelle and {De Vries}, {Cor P.} and {Den Herder}, {Jan Willem} and Chris Done and Tadayasu Dotani and Ken Ebisawa and Eckart, {Megan E.} and Teruaki Enoto and Yuichiro Ezoe and Fabian, {Andrew C.} and Carlo Ferrigno and Foster, {Adam R.} and Ryuichi Fujimoto and Yasushi Fukazawa and Akihiro Furuzawa and Massimiliano Galeazzi and Gallo, {Luigi C.} and Poshak Gandhi and Margherita Giustini and Andrea Goldwurm and Liyi Gu and Matteo Guainazzi and Yoshito Haba and Kouichi Hagino and Kenji Hamaguchi and Harrus, {Ilana M.} and Isamu Hatsukade and Katsuhiro Hayashi and Takayuki Hayashi and Kiyoshi Hayashida and Aya Kubota",
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AU - Hitomi Collaboration

AU - Aharonian, Felix

AU - Akamatsu, Hiroki

AU - Akimoto, Fumie

AU - Allen, Steven W.

AU - Angelini, Lorella

AU - Audard, Marc

AU - Awaki, Hisamitsu

AU - Axelsson, Magnus

AU - Bamba, Aya

AU - Bautz, Marshall W.

AU - Blandford, Roger

AU - Brenneman, Laura W.

AU - Brown, Gregory V.

AU - Bulbul, Esra

AU - Cackett, Edward M.

AU - Chernyakova, Maria

AU - Chiao, Meng P.

AU - Coppi, Paolo S.

AU - Costantini, Elisa

AU - De Plaa, Jelle

AU - De Vries, Cor P.

AU - Den Herder, Jan Willem

AU - Done, Chris

AU - Dotani, Tadayasu

AU - Ebisawa, Ken

AU - Eckart, Megan E.

AU - Enoto, Teruaki

AU - Ezoe, Yuichiro

AU - Fabian, Andrew C.

AU - Ferrigno, Carlo

AU - Foster, Adam R.

AU - Fujimoto, Ryuichi

AU - Fukazawa, Yasushi

AU - Furuzawa, Akihiro

AU - Galeazzi, Massimiliano

AU - Gallo, Luigi C.

AU - Gandhi, Poshak

AU - Giustini, Margherita

AU - Goldwurm, Andrea

AU - Gu, Liyi

AU - Guainazzi, Matteo

AU - Haba, Yoshito

AU - Hagino, Kouichi

AU - Hamaguchi, Kenji

AU - Harrus, Ilana M.

AU - Hatsukade, Isamu

AU - Hayashi, Katsuhiro

AU - Hayashi, Takayuki

AU - Hayashida, Kiyoshi

AU - Kubota, Aya

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N2 - We present the results from the Hitomi Soft Gamma-ray Detector (SGD) observation of the Crab nebula. The main part of SGD is a Compton camera, which in addition to being a spectrometer, is capable of measuring polarization of gamma-ray photons. The Crab nebula is one of the brightest X-ray/gamma-ray sources on the sky, and the only source from which polarized X-ray photons have been detected. SGD observed the Crab nebula during the initial test observation phase of Hitomi. We performed data analysis of the SGD observation, SGD background estimation, and SGD Monte Carlo simulations and successfully detected polarized gamma-ray emission from the Crab nebula with only about 5 ks exposure time. The obtained polarization fraction of the phase-integrated Crab emission (sum of pulsar and nebula emissions) is (22.1%±10.6%), and the polarization angle is 110°.7 + 13°.2/-13°.0 in the energy range of 60.160 keV (the errors correspond to the 1 σ deviation). The confidence level of the polarization detection was 99.3%. The polarization angle measured by SGD is about one sigma deviation with the projected spin axis of the pulsar, 124°.0 ± 0°.0.1.

AB - We present the results from the Hitomi Soft Gamma-ray Detector (SGD) observation of the Crab nebula. The main part of SGD is a Compton camera, which in addition to being a spectrometer, is capable of measuring polarization of gamma-ray photons. The Crab nebula is one of the brightest X-ray/gamma-ray sources on the sky, and the only source from which polarized X-ray photons have been detected. SGD observed the Crab nebula during the initial test observation phase of Hitomi. We performed data analysis of the SGD observation, SGD background estimation, and SGD Monte Carlo simulations and successfully detected polarized gamma-ray emission from the Crab nebula with only about 5 ks exposure time. The obtained polarization fraction of the phase-integrated Crab emission (sum of pulsar and nebula emissions) is (22.1%±10.6%), and the polarization angle is 110°.7 + 13°.2/-13°.0 in the energy range of 60.160 keV (the errors correspond to the 1 σ deviation). The confidence level of the polarization detection was 99.3%. The polarization angle measured by SGD is about one sigma deviation with the projected spin axis of the pulsar, 124°.0 ± 0°.0.1.

KW - Instrumentation: polarimeters

KW - Polarization-X-rays: individual (Crab)

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