• Title/Summary/Keyword: spectral space

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The Spectral Sharpness Angle of Gamma-ray Bursts

  • Yu, Hoi-Fung;van Eerten, Hendrik J.;Greiner, Jochen;Sari, Re'em;Bhat, P. Narayana;Kienlin, Andreas von;Paciesas, William S.;Preece, Robert D.
    • Journal of Astronomy and Space Sciences
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    • v.33 no.2
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    • pp.109-117
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    • 2016
  • We explain the results of Yu et al. (2015b) of the novel sharpness angle measurement to a large number of spectra obtained from the Fermi gamma-ray burst monitor. The sharpness angle is compared to the values obtained from various representative emission models: blackbody, single-electron synchrotron, synchrotron emission from a Maxwellian or power-law electron distribution. It is found that more than 91% of the high temporally and spectrally resolved spectra are inconsistent with any kind of optically thin synchrotron emission model alone. It is also found that the limiting case, a single temperature Maxwellian synchrotron function, can only contribute up to 58+23−18% of the peak flux. These results show that even the sharpest but non-realistic case, the single-electron synchrotron function, cannot explain a large fraction of the observed spectra. Since any combination of physically possible synchrotron spectra added together will always further broaden the spectrum, emission mechanisms other than optically thin synchrotron radiation are likely required in a full explanation of the spectral peaks or breaks of the GRB prompt emission phase.

MEDIUM RESOLUTION SPECTRAL LIBRARY OF LATE-TYPE STELLAR TEMPLATES IN NEAR-INFRARED BAND

  • Le, Huynh Anh Nguyena;Kang, Won-Seok;Pak, Soo-Jong;Im, Myung-Shin;Lee, Jeong-Eun;Ho, Luis C.;Pyo, Tae-Soo;Jaffe, Daniel T.
    • Journal of The Korean Astronomical Society
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    • v.44 no.4
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    • pp.125-134
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    • 2011
  • We present medium resolution (R = 5000 - 6000) spectra in the near-infrared band, 1.4 - 1.8 ${\mu}m$, for template stars in G, K, and M types observed by the echelle spectrometer, IRCS, at the SUBARU 8.2 m telescope. The identification of lines is based on the spectra of Arcturus (K2 III) in the literature. We measured the equivalent of widths and compared our results to those of Meyer et al. (1998). We conclude that our spectral resolution (R = 6000) data can investigate more accurately the properties of lines in stellar spectra. The library of the template stellar spectra in ASCII format are available for download on the World Wide Web.