TY - JOUR
T1 - Time-Resolved Spectral Variability of the Prompt Emission from GRB 070125 Observed with Suzaku/WAM
AU - Onda, Kaori
AU - Tashiro, Makoto S.
AU - Nakagawa, Yujin E.
AU - Yamaoka, Kazutaka
AU - Terada, Yukikatsu
AU - Ohno, Masanori
AU - Sugita, Satoshi
AU - Sakamoto, Takanori
AU - Toma, Kenji
AU - Gandhi, Poshak
AU - Kodak, Natsuki
AU - Iwakiri, Wataru
AU - Urata, Yuji
AU - Yamauchi, Makoto
AU - Fukazawa, Yasushi
PY - 2010
Y1 - 2010
N2 - Time-resolved spectral analyses of GRB 070125 with significant photon detections over the MeV regime using Suzaku/WAM data are reported. The prompt emission interval was divided into 10 time regions, and their spectra were reproduced by a Band function or a cutoff power-law model. The spectra show a complex evolution; a soft-hard-soft trend is seen, rather than a typical hard-to-soft monotonic variation. In addition, a flat spectral slope in the low-energy band exceeding the slope expected from a simple synchrotron emission model is suggested in one of the time regions. These results imply that the internal shocks in the relativistic jet of GRB 070125 have different physical conditions. There is a possible excess at ∼ 2.2 MeV in the spectrum of 33 seconds after the trigger at a significant level of ≈ 98.5%, where the continuum spectrum is not reproduced by the Band function. These properties are only shown during the short prompt time interval of the prompt emission, and emphasize the utility of the Suzaku/WAM for the study of gamma-ray bursts.
AB - Time-resolved spectral analyses of GRB 070125 with significant photon detections over the MeV regime using Suzaku/WAM data are reported. The prompt emission interval was divided into 10 time regions, and their spectra were reproduced by a Band function or a cutoff power-law model. The spectra show a complex evolution; a soft-hard-soft trend is seen, rather than a typical hard-to-soft monotonic variation. In addition, a flat spectral slope in the low-energy band exceeding the slope expected from a simple synchrotron emission model is suggested in one of the time regions. These results imply that the internal shocks in the relativistic jet of GRB 070125 have different physical conditions. There is a possible excess at ∼ 2.2 MeV in the spectrum of 33 seconds after the trigger at a significant level of ≈ 98.5%, where the continuum spectrum is not reproduced by the Band function. These properties are only shown during the short prompt time interval of the prompt emission, and emphasize the utility of the Suzaku/WAM for the study of gamma-ray bursts.
KW - Gamma rays: burst
KW - Gamma rays: observations
KW - X-rays: individual (GRB 070125)
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U2 - 10.1093/pasj/62.3.547
DO - 10.1093/pasj/62.3.547
M3 - Article
AN - SCOPUS:77954775478
SN - 0004-6264
VL - 62
SP - 547
EP - 556
JO - Publication of the Astronomical Society of Japan
JF - Publication of the Astronomical Society of Japan
IS - 3
ER -