Archival searches for transient optical emission in the error box of the 1991 January 22 gamma-ray burst

Javier Gorosabel, Alberto Castro-Tirado

Published 1998-06-23Version 1

We present here the results of a study carried out at the Harvard College Observatory Plate Collection. We examined 3995 plates covering the error box of the gamma-ray burst GRB 910122, over a time span of 90 yr (from 1889 to 1979). The total exposure time is ~0.55 yr. No convincing evidence of optical transient emission was found within the GRB 910122 IPN error box. However, a possible OT was found outside the GRB 910122 error box. Optical ground based observations have revealed a V~22.3 object consistent with the position of the new object. The colours of the object are typical of a K7/M0 star or a reddened galaxy, which could have caused the OT, but the fact that the object is far away from the GRB error box makes both events unrelated.