Late-Time Optical Afterglow Observations with LBT and MDM
Using the 2．4m MDM and 8．4m Large Binocular Telescope,We observed nine GRB afterglows to systematicallyprobe the late time behaviors of afterglows including jet breaks,flares,and supernova bumps．In particular,the LBTobservations have typical flux limits of 25-26 mag in the Sloan r1 band,which allows US to extend the temporal baselinefor measuring jet breaks by another decade in time scale．We detected four jet breaks(including a“textbookjet breakin GRB070125) and a fifth candidate,all of which are not detectable without deep,late time optical observations．In theother four cases,we do not detect the jet breaks either because of contamination from the host galaxy light,the presence of asupemova bump,or the intrinsic faintness of the optical afterglow．This suggests that the basic picture that GRBs are collimatedis still valid and that the apparent lack of Swift jet breaks is due to poorly sampled afterglow light curves,particularly at latetimes．Besides the jet breaks,we also detected late time flares,which could attribute to late ceutral engine activities,and twosupernova bumps．
Gamma-ray bursts
X.Dai K.Z.Stanek P.M.Garnavich
Department of Astronomy,Ohio State University,Columbus,oH 43210,UsA Department of Physics,University of Notre Dame,Notre Dame,IN46556,USA
国际会议
2008 NanJing Gamma-Ray Burst Conference(2008年伽马暴国际研讨会)
南京
英文
93-98
2008-06-23（万方平台首次上网日期，不代表论文的发表时间）