A New Radio Detection of the Transient Bursting Source GCRT J1745−3009

GCRT J1745-3009 is a transient bursting radio source located in the directionof the Galactic center, discovered in 330 MHz VLA observations from 2002September 30--October 1 by Hyman et al. We have searched for bursting activityfrom GCRT J1745-3009 in nearly all of the available 330 MHz VLA observations ofthe Galactic center since 1989 as well as in 2003 GMRT observations. We reporta new radio detection of the source in 330 MHz GMRT data taken on 2003September 28. A single ~0.5 Jy burst was detected, approximately 3x weaker thanthe five bursts detected in 2002. Due to the sparse sampling of the 2003observation, only the decay portion of a single burst was detected. We presentadditional evidence indicating that this burst is an isolated one, but wecannot completely rule out additional undetected bursts that may have occuredwith the same ~77 min. periodicity observed in 2002 or with a differentperiodicity. Assuming the peak emission was detected, the decay time of theburst, ~2 min, is consistent with that determined for the 2002 bursts. Based onthe total time for which we have observations, we estimate that the source hasa duty cycle of roughly 10%.Comment: 16 pages including 4 figures. Submitted to The Astrophysical Journa