Li 2007 长伽玛暴不是标准烛光之Amati关系
主要内容:
重新讨论Amati关系，用Eiso = a + b log Epeak，把长伽玛暴按红移从小到大分成4组，结果a和b变化很大，说明该关系随红移变化，不能作为标准烛光。
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文章信息:
arXiv:0705.4401 [ps, pdf, other] : Title: Are Gamma-Ray Bursts Standard Candles?
Authors: Li-Xin Li
Comments: 4 pages, including 4 figures. To appear in the proceedings of "070228: The Next Decade of GRB afterglows", Amsterdam, 19-23 March 2007
By dividing a sample of 48 long-duration gamma-ray bursts (GRBs) into four groups with redshift from low to high and fitting each group with the Amati relation log Eiso = a + b log Epeak, I find that parameters a and b vary with the mean redshift of the GRBs in each group systematically and significantly. The results suggest that GRBs evolve strongly with the cosmic redshift and hence are not standard candles.
http://www.arxiv.org/abs/0704.3128
Variation of the Amati Relation with the Cosmological Redshift: a Selection Effect or an Evolution Effect?
Abstract: Because of the limit in the number of gamma-ray bursts (GRBs) with available redshifts and spectra, all current investigations on the correlation among GRB variables use burst samples with redshifts that span a very large range. The evolution and selection effects have thus been ignored, which might have important influence on the results. In this Letter, we divide the 48 long-duration GRBs in Amati (2006, 2007) into four groups with redshift from low to high, each group contains 12 GRBs. Then we fit each group with the Amati relation $\log E_\iso = a + b \log E_\p$, and check if the parameters $a$ and $b$ evolve with the GRB redshift. We find that $a$ and $b$ vary with the mean redshift of the GRBs in each group systematically and significantly. Monte-Carlo simulations show that there is only $\sim 4$ percent of chance that the variation is caused by the selection effect arising from the fluence limit. Hence, our results may indicate that GRBs evolve strongly with the cosmological redshift.
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