Swift and Suzaku Observations of the X-Ray Afterglow from the GRB 060105

[摘要] ResultsarepresentedofearlyX-rayafterglowobservationsofGRB060105bySwiftandSuzaku.Thebright,longgamma-rayburstGRB060105triggeredtheSwiftBurstAlertTelescopeat06:49:28on2006January5($$T_0$$).TheSuzakuteamcommencedapre-plannedtargetofopportunityobservationat19 ks(5.3 hr)aftertheSwifttrigger.TheX-rayfluxfadedduringobservationsfrom$$6.8imes10^{-9},mathrm{erg},mathrm{s}^{-1},mathrm{cm}^{-2}$$(at$$T_0+87,mathrm{s}$$withtheSwift/XRT)to$$1.5imes10^{-13},mathrm{erg},mathrm{s}^{-1},mathrm{cm}^{-2}$$[at$$T_0+94hbox{}{--}101,mathrm{ks}$$withtheSuzakuX-rayImagingSpectrometer(XIS)]inthe2–10 keVenergyband.Followingpromptemissionandsuccessiveverysteepdecay,ashallowdecaywasobservedfrom$$T_0+187,mathrm{s}$$to$$T_0+1287,mathrm{s}$$.Afteranobservationgapduring$$T_0+(1.5hbox{}{--}3);mathrm{ks}$$,anextremelyearlysteepdecaywasobservedin$$T_0+(4hbox{}{--}30);mathrm{ks}$$.Thelightcurveflattenedagainat$$T_0+30,mathrm{ks}$$,andanothersteepdecayfollowedfrom$$T_0+50,mathrm{ks}$$totheendofobservations.Bothsteepdecaysexhibiteddecayindicesof2.3–2.4.Thisveryearlybreak,ifitisajetbreak,istheearliestcaseamongX-rayafterglowobservations,suggestingaverynarrowjetwhoseopeningangleiswellbelow$$1^circ$$.TheuniqueSuzaku/XISdataallowustosetverytightupperlimitsonlineemissionorabsorptioninthisGRB.Forthereportedpseudo-redshiftof$$z=4.0pm1.3$$theupperlimitontheironlineequivalentwidthis50 eV.

[学科分类] 天文学(综合)

[关键词] "gamma-ray burst: general";"radiation mechanisms: non-thermal";"relativistic jet";"X-rays: individual (GRB 060105)";"X-rays: stars acceleration of particles"