论文标题

Chandra(2000-2014)发现

Extragalactic fast X-ray transient candidates discovered by Chandra (2000-2014)

论文作者

Quirola-Vasquez, J., Bauer, F. E., Jonker, P. G., Brandt, W. N., Yang, G., Levan, A. J., Xue, Y. Q., Eappachen, D., Zheng, X. C., Luo, B.

论文摘要

外乳外快速X射线瞬变(FXRT)是几秒钟至小时的X射线光子的短闪光,其起源不确定。在大多数情况下,我们对它们的物理机制和祖细胞系统的无知部分是由于缺乏明确的多波长对应物,因为它们仅偶然地被鉴定出来。我们在Chandra源目录中使用直接的X射线耀斑搜索算法对FXRT进行了系统的搜索(数据版本2.0; 169.6 ms以592.4 v $^{2} $在仅使用$ | b | b |> 10^{\ circ} $和2015年之前的观测值,并在2015年之前和整个多人构成了各种序列的序列,以列出各种序列。我们报告了来自214,701个来源的父样本的14个FXRT候选者的检测。候选人在1 $ \ times $ 10 $^{ - 13} $到2 $ \ times $ 10 $ 10 $^{ - 10} $ erg cm $^{ - 2} $ s $ s $^{ - 1} $和$ t_ {90} $值的峰值0.5-7 keV通量之间。该样本可以细分为两组:六个“附近” FXRT发生在$ d \ lyssim $ 100 mpc和八个“远处” fxrts之内,可能是红移$ \ gtrsim $ 0.1。三个遥远的FXRT候选者表现出具有高原($ {\ about} $ 1-3 ks的持续时间)的光曲线,其次是幂律衰减和X射线频谱软化,类似于先前报道的FXRT CDF-S〜XT2,提出的磁力磁力磁力启动的Binart Bariare Healtron Setron Star Merger事件。应用完整性校正后,我们计算了附近和遥远的样本的事件率,为53.7 $ _ { - 15.1}^{+22.6} $和28.2 $ _ { - 6.9}^{+9.8}^{+9.8} $ deg $^$^$^{ - 2} $ yr $ yr $ yr $^{ - 1} $。这个新颖的Chandra检测到的样本外层次FXRT候选者虽然规模适中,但在表征这些神秘事件的各种特性,性质和可能的祖细胞方面,却打破了新的基础。

Extragalactic Fast X-ray Transients (FXRTs) are short flashes of X-ray photons spanning a few seconds to hours, with an uncertain origin. Our ignorance about their physical mechanisms and progenitor systems is due in part to the lack of clear multi-wavelength counterparts in most cases because they only have been identified serendipitously. We develop a systematic search of FXRTs using a straightforward X-ray flare search algorithm, in the Chandra Source Catalog (Data Release 2.0; 169.6 Ms over 592.4 deg$^{2}$ using only observations with $|b|>10^{\circ}$ and before 2015), incorporating various multi-wavelength constraints to rule out Galactic contamination and characterize the candidates. We report the detection of 14 FXRT candidates from a parent sample of 214,701 sources. Candidates have peak 0.5-7 keV fluxes between 1$\times$10$^{-13}$ to 2$\times$10$^{-10}$ erg cm$^{-2}$ s$^{-1}$ and $T_{90}$ values from 4 to 48 ks. The sample can be subdivided into two groups: six "nearby" FXRTs that occurred within $d\lesssim$100 Mpc and eight "distant" FXRTs with likely redshifts $\gtrsim$0.1. Three distant FXRT candidates exhibit light curves with a plateau (${\approx}$1-3 ks duration) followed by a power-law decay and X-ray spectral softening, similar to what was observed for the previously reported FXRT CDF-S~XT2, a proposed magnetar-powered binary neutron star merger event. After applying completeness corrections, we calculate event rates for the nearby and distant samples of 53.7$_{-15.1}^{+22.6}$ and 28.2$_{-6.9}^{+9.8}$ deg$^{-2}$ yr$^{-1}$, respectively. This novel sample of Chandra-detected extragalactic FXRT candidates, although modest in size, breaks new ground in terms of characterizing the diverse properties, nature, and possible progenitors of these enigmatic events.

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