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arXiv 0708.2106astro-ph
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长伽马射线暴在本机宇宙中有多常见?

How common are long Gamma-Ray Bursts in the Local Universe?

Robert Chapman, Nial R. Tanvir, Robert S. Priddey, Andrew J. Levan

摘要:

到目前为止,探测到的两个最近的伽马射线暴(GRB 980425和060218)都是低亮度、光谱柔和、持续时间长的爆发,光变曲线平滑、单峰。只有大约100个伽玛暴被测量到红移,例如,仅在BATSE目录中就有2704个伽玛暴。因此,似乎有理由认为,其他附近的伽玛暴已经被观测到,但没有被确定为相对较近。在这里,我们寻找BATSE长持续时间伽玛暴和星系样品的后退速度v <= 11,000 km/s(z = 0.0367,~ 155 Mpc)从两个目录的附近星系之间的统计相关性。我们还研究了使用突发子样本的相关性,这些子样本的属性类似于两个已知的附近突发。我们的研究结果表明,整个长伽玛暴样本的相关性保持一致,零出最高半径考虑,而一个子样本选择低通量,光谱软,平滑的单峰光变曲线(177爆发)表明增加的相关性与星系内~ 155 Mpc。测量的相关性(样本的28% +/- 16%)表明BATSE每年观察到2到9个长持续时间的伽玛射线暴,类似于伽玛射线暴980425和060218,并且距离相似。这意味着在155 Mpc范围内观测到的局部速率密度为700 +/- 360 Gpc^{-3}yr^{-1}。

英文摘要:

The two closest Gamma-Ray Bursts so far detected (GRBs 980425 & 060218) were both under-luminous, spectrally soft, long duration bursts with smooth, single-peaked light curves. Only of the order of 100 GRBs have measured redshifts, and there are, for example, 2704 GRBs in the BATSE catalogue alone. It is therefore plausible that other nearby GRBs have been observed but not identified as relatively nearby. Here we search for statistical correlations between BATSE long duration GRBs and galaxy samples with recession velocities v <= 11,000 km/s (z = 0.0367, ~ 155 Mpc) selected from two catalogues of nearby galaxies. We also examine the correlations using burst sub-samples restricted to those with properties similar to the two known nearby bursts. Our results show correlation of the entire long GRB sample to remain consistent with zero out to the highest radii considered whereas a sub-sample selected to be low fluence, spectrally soft, with smooth single-peaked light curves (177 bursts) demonstrates increased correlation with galaxies within ~ 155 Mpc. The measured correlation (28% +/- 16% of the sample) suggests that BATSE observed between 2 and 9 long duration GRBs per year similar to, and from within similar distances to GRBs 980425 and 060218. This implies an observed local rate density (to BATSE limits) of 700 +/- 360 Gpc^{-3}yr^{-1} within 155 Mpc.

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