학술논문
Discovery of the Optical Transient of the Gamma Ray Burst 990308
Document Type
Working Paper
Author
Schaefer, Bradley E.; Snyder, J. A.; Hernandez, J.; Roscherr, B.; Deng, M.; Ellmann, N.; Bailyn, C.; Rengstorf, A.; Smith, D.; Levine, A.; Barthelmy, S.; Butterworth, P.; Hurley, K.; Cline, T.; Meegan, C.; Kouveliotou, C.; Kippen, R.; Park, H.; Williams, G.; Porrata, R.; Bionta, R.; Hartmann, D.; Band, D.; Frail, D.; Kulkarni, S.; Bloom, J.; Djorgovski, S.; Harris, F.; Abad, C.; Adams, B.; Andrews, P.; Baltay, C.; Bongiovanni, A.; Briceno, C.; Bruzual, G.; Coppi, P.; Della Prugna, F.; Dubuc, A.; Emmet, W.; Ferrin, I.; Fuenmayor, F.; Gebhard, M.; Herrera, D.; Honeycutt, K.; Magris, G.; Mateu, J.; Muffson, S.; Musser, J.; Naranjo, O.; Oemler, A.; Pacheco, R.; Paredes, G.; Rengel, M.; Romero, L.; Rosenzweig, P.; al, C. Sabbey et
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Subject
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Abstract
The optical transient of the faint Gamma Ray Burst 990308 was detected by the QUEST camera on the Venezuelan 1-m Schmidt telescope starting 3.28 hours after the burst. Our photometry gives $V = 18.32 \pm 0.07$, $R = 18.14 \pm 0.06$, $B = 18.65 \pm 0.23$, and $R = 18.22 \pm 0.05$ for times ranging from 3.28 to 3.47 hours after the burst. The colors correspond to a spectral slope of close to $f_{\nu} \propto \nu^{1/3}$. Within the standard synchrotron fireball model, this requires that the external medium be less dense than $10^{4} cm^{-3}$, the electrons contain $> 20%$ of the shock energy, and the magnetic field energy must be less than 24% of the energy in the electrons for normal interstellar or circumstellar densities. We also report upper limits of $V > 12.0$ at 132 s (with LOTIS), $V > 13.4$ from 132-1029s (with LOTIS), $V > 15.3$ at 28.2 min (with Super-LOTIS), and a 8.5 GHz flux of $< 114 \mu Jy$ at 110 days (with the Very Large Array). WIYN 3.5-m and Keck 10-m telescopes reveal this location to be empty of any host galaxy to $R > 25.7$ and $K > 23.3$. The lack of a host galaxy likely implies that it is either substantially subluminous or more distant than a red shift of $\sim 1.2$.
Comment: ApJ Lett submitted, 5 pages, 2 figures, no space for 12 coauthors
Comment: ApJ Lett submitted, 5 pages, 2 figures, no space for 12 coauthors