Spectral and polarization properties of photospheric emission from stratified jets

Hirotaka Ito, Shigehiro Nagataki, Jin Matsumoto, Shiu Hang Lee, Alexey Tolstov, Jirong Mao, Maria Dainotti, Akira Mizuta

研究成果: Article査読

26 被引用数 (Scopus)


We explore the spectral and polarization properties of photospheric emissions from stratified jets in which multiple components, separated by sharp velocity shear regions, are distributed in lateral directions. Propagation of thermal photons injected at a high optical depth region are calculated until they escape from the photosphere. It is found that the presence of the lateral structure within the jet leads to the nonthermal feature of the spectra and significant polarization signal in the resulting emission. The deviation from thermal spectra, as well as the polarization degree, tends to be enhanced as the velocity gradient in the shear region increases. In particular, we show that emissions from multicomponent jet can reproduce the typical observed spectra of gamma-ray bursts irrespective of the position of the observer when a velocity shear region is closely spaced in various lateral (θ) positions. The degree of polarization associated with the emission is significant (>few percent) at a wide range of observer angles and can be higher than 30%.

ジャーナルAstrophysical Journal
出版ステータスPublished - 2014 7 10

ASJC Scopus subject areas

  • 天文学と天体物理学
  • 宇宙惑星科学


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