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arXiv 1005.1876astro-ph.HEastro-ph.CO
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伽马射线暴宿主星系的理论研究

A Theoretical Investigation on the Gamma-ray Burst Host Galaxies

J. Mao

摘要:

长时间的伽马射线暴(LGRB)被认为与恒星的形成有关。我们采用了一个星系演化模型,在该模型中,在给定的红移下,可以得到在维里化暗晕内的恒星形成过程。本文假设伽马射线暴(GRB)的宿主星系是小暗晕中的恒星形成星系。在星系演化时间约为$10^7$ yr的几倍,暗晕质量约为$5\times 10^{11}M_\odot$的条件下,利用我们的模型计算了不同红移的LGRB宿主星系的恒星形成率。并对这些宿主的相关恒星质量、光度和金属丰度进行了估算。我们进一步计算了伽玛暴余辉辐射的X射线和光吸收。从我们的模型计算可知,在红移较高的情况下,在尘埃和金属成分局部释放的情况下,宿主星系的SFR较大,余辉在X射线波段和光学波段的吸收较强,围绕着GRB环境。这些模型的预测与{ \it Swift}和其他观测数据进行了比较。在较低的红移$z<1$,由于涉及到一些宿主星系的合并和相互作用,一个单一的物理过程不足以完全解释所观察到的各种现象。

英文摘要:

Long-duration gamma-ray bursts(LGRBs) are believed to be linked with the star formation. We adopt a galactic evolution model, in which the star formation process inside the virialized dark halo at given redshift can be achieved. In this paper, the gamma-ray burst(GRB) host galaxies are assumed to be the star-forming galaxies within the small dark halos. The star formation rates(SFRs) in the host galaxies of LGRBs at different redshifts have been derived from our model with the galactic evolutionary time about a few times of $10^7$ yr and the dark halo mass of about $5\times 10^{11}M_\odot$. The related stellar masses, luminosities and metallicities of these hosts are estimated as well. We further calculate the X-ray and optical absorption of GRB afterglow emission. From our model calculation, at higher redshift, the SFR of host galaxy is larger, the absorption in X-ray band and optical band of GRB afterglow is stronger, in the condition that the dust and metal components are released locally, surrounding the GRB environment. These model predictions are compared with the {\it Swift} and other observational data. At lower redshift $z<1$, as the merger and interaction of some host galaxies are involved, one monolithic physical process is not sufficient to fully explain all kinds of observed phenomena.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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