LOTIS Upper Limits and the Prompt OT from GRB 990123.

Williams, G. G. ; Hartmann, D. H. ; Park, H. S. ; Porrata, R. A. ; Ables, E.

Technical Information Center Oak Ridge Tennessee

关键词: Cosmic gamma bursts;    Limiting values;    Photon emission;    Afterglow;    Lawrence Livermore Laboratory;   

RP-ID  :  DE200415006145

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

GRB 990123 established the existence of prompt optical emission from gamma-ray bursts (GRBs). The Livermore Optical Transient Imaging System (LOTIS) has been conducting a fully automated search for this kind of simultaneous low energy emission from GRBs since October 1996. Although LOTIS has obtained simultaneous, or near simultaneous, coverage of the error boxes obtained with BATSE, IPN, XTE, and BeppoSAX for several GRBs, image analysis resulted in only upper limits. The unique gamma-ray properties of GRB 990123, such as very large fluence (top 0.4%) and hard spectrum, complicate comparisons with more typical bursts. We scale and compare gamma-ray properties, and in some cases afterglow properties, from the best LOTIS events to those of GRB 990123 in an attempt to determine whether the prompt optical emission of this event is representative of all GRBs. Furthermore, using LOTIS upper limits in conjunction with the relativistic blast wave model, we weakly constrain the GRB and afterglow parameters such as density of the circumburster medium and bulk Lorentz factor of the ejecta.