Multiple-Component Analysis of the Time-Resolved Spectra of GRB 041006: A Clue to the Nature of the Underlying Soft Component of GRBs

作者：Shirasaki Yuji^*; Yoshida Atsumasa; Kawai Nobuyuki; Tamagawa Toru; Sakamoto Takanori; Suzuki Motoko; Nakagawa Yujin; Kobayashi Akina; Sugita Satoshi; Takahashi Ichiro; Arimoto Makoto; Shimokawabe Takashi; Pazmino Nicolas Vasquez; Ishimura Takuto; Sato Rie; Matsuoka Masaru; Fenimore Edward E; Galassi Mark; Lamb Donald Q; Graziani Carlo; Donaghy Timothy Q; Atteia Jean Luc; Pelangeon Alexandre; Vanderspek Roland; Crew Geoffrey B; Doty John P; Villasenor Joel

来源：Publications of the Astronomical Society of Japan, 2008, 60(4): 919-931.

• gamma-rays: bursts
• X-rays: bursts
• X-rays: individual (GRB 041006)

GRB 041006 was detected by HETE-2 on 2004 October 06. The light curves in four different energy bands display different features. At higher energy bands several peaks are seen in the light curve, while at lower energy bands a single broader bump dominates. It is expected that these different features are the result of a mixture of several components, each of which has different energetics and variability. We analyzed the time-resolved spectra, which were resolved into several components. These components can be classified into two distinct classes. One is a component that has an exponential decay of E(p) with a characteristic timescale shorter than similar to 30 s; its spectrum is well represented by a broken power-law function, which is frequently observed in many prompt GRB emissions, so it should have an internal-shock origin. Another is a component whose E(p) is almost unchanged with a characteristic timescale longer than similar to 60 s, and shows a very soft emission and slower variability. The spectrum is characterized by either a broken power law or a black-body spectrum. By assuming that the soft component is a thermal emission, the radiation radius is initially 4.4 x 10(6) km, which is a typical radius of a blue supergiant, and its expansion velocity is 2.4 x 10(5) km s(-1) in the source frame.

• 出版日期2008
• 单位中国科学院国家天文台