Salvaterra 2007 Swift对高红移伽玛暴的观测

主要内容:
从06年到现在大约有6个红移大于5的伽玛暴，数量、流量等和理论模型吻合。

精彩摘抄:


文章信息:
arXiv:0706.0657 [ps, pdf, other] : Title: On the detection of very high redshift Gamma Ray Bursts with Swift
Authors: R. Salvaterra, S. Campana, G. Chincarini, G. Tagliaferri, S. Covino
Comments: 5 pages, 2 figures, MNRAS in press

We compute the probability to detect long Gamma Ray Bursts (GRBs) at z>5 with Swift, assuming that GRBs form preferentially in low-metallicity environments. The model fits well both the observed BATSE and Swift GRB differential peak flux distribution and is consistent with the number of z>2.5 detections in the 2-year Swift data. We find that the probability to observe a burst at z>5 becomes larger than 10% for photon fluxes P<1>5 bursts in the Swift catalog is ~10%-30% depending on the adopted metallicity threshold for GRB formation. We propose to use the computed probability as a tool to identify high redshift GRBs. By jointly considering promptly-available information provided by Swift and model results, we can select reliable z>5 candidates in a few hours from the BAT detection. We test the procedure against last year Swift data: only three bursts match all our requirements, two being confirmed at z>5. Other three possible candidates are picked up by slightly relaxing the adopted criteria. No low-z interloper is found among the six candidates.