| 其他摘要 | Gamma-ray burst（briefly called GRB）is the most violent burst, which largely emergesgamma-ray emission during short time. In Galaxy plane, GRBs are isotropic. In radial direction,GRBs are inhomogeneous. The duration of GRB ranges from milliseconds to thousand seconds,while durations of long bursts are greater than 2 seconds and durations of short bursts are lessthan 2 seconds. For short burst, the typical duration is 0.3 seconds. For long burst, the typicalduration is 30 seconds. The pulse of GRB is asymmetric with rise time less than decay time.The spectrum of GRBs can be discribed by band function which consists of three parameters:low energy index (typical value: -1)、high energy index (typical value: -2.2) and peak energy(typical value: 250 keV). The GRBs are classified into three types: X-ray flash (briefly calledXRF)、X-ray rich GRB (briefly called XRR) and classical GRB (briefly called C-GRB) basedon energy band in which the flux largely emerges. In GRBs, the peak flux of low energy is lateto the peak flux of high energy, and the pulse keeps self-similar both in low and high energy.Some GRBs have thermal emission in spectrum. The redshift distribution between short burstsand long bursts is different. And the spectrum of short burst is harder than long burst.XRF is GRB, which has large flux in X-ray energy. XRF hold in log[S X(25 -50keV)/S (50 - 100keV)] > 1.32. The T90 is similar among XRF、XRR and C-GRB, exceptfor peak energy. For GRB 011121 and XRF 020903, the afterglows have a rebright whichis caused by SNe. The XRF and low-luminous GRB have a similar typical luminosity value1047 ergs??1, but XRF has different z - t relationship from subluminous-long GRB.X-ray flares are short flare in X-ray afterglow of GRBs. The pulses of X-ray flares aresimilar to the pulses of GRBs. The durations of X-ray flares range from hundred seconds tothousand seconds. In the fraction of GRBs, the flux of X-ray flare reaches the flux of promptemission. The spectrum of X-ray flare is harder than the spectrum of X-ray afterglow. DuringX-ray flare, the spectrum evolves from hardness to softness. The peak flux of low energy islate to peak flux of high energy during X-ray flare. The early X-ray flares harden the late X-rayflares, but there is a similar w - tp relationship between the early X-ray flare and the late X-ray p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 12.0px Helvetica}
span.s1 {font: 8.0px Helvetica}flare. In some of X-ray flares, there is thermal emission in spectrum. The optical rebright isrelated to X-ray flare, because there is a similar w - tp relationship between the optical rebrightand X-ray flare. For short bursts, their X-ray flares are dimmer than X-ray flares of long bursts.For short bursts, their X-ray flares reside both in early-type galaxies and late-type galaxies. Thespectrum of X-ray flare evolves from hardness to softness both in short bursts and long bursts,while there is a similar w - tp relationship for X-ray flares both in short bursts and long bursts.We make a invetigation of X-ray flare among XRFs、XRRs and C-GRBs. XRFs、XRRsand C-GRBs can be obtained from Swift-BAT observation during time from December 17, 2004to December 2, 2016. X-ray flares are from Chincarini et al. (2010) and Yi et al. (2016),respectively. For Chincarini et al. (2018), X-ray flares are observed between April, 2005 andMarch, 2008. For Yi et al. (2018), X-ray flares are observed between April, 2005 and March,2015. In GRBs with X-ray flare, we examine the T90 distribution among XRFs、XRRs andC-GRBs. We examine the ratio distribution between X-ray flare fluence and prompt emissionfluence among XRFs、XRRs and C-GRBs. We examine the duration distribution and the peaktime distribution for X-ray flare among XRFs、XRRs and C-GRBs. We examine the correlationbetween the duration and the peak time for X-ray flare among XRFs、XRRs and C-GRBs. Weexamine the distribution in planeΔF/F-w/tp for X-ray flare among XRFs、XRRs and C-GRBs.We find that the ratio distribution between X-ray flare fluence and prompt emission fluence isdifferent between XRFs and C-GRBs. We find that the correlation between the duration and thepeak time of X-ray flare is different between XRFs and C-GRBs. XRFs include more numberof bright X-ray flares than C-GRBs. X-ray flares may be related to XRFs. Some of GRBs withbright X-ray flares may be inclined to XRFs. |
修改评论