GRG18 5a

Jumping ahead to the 3:30 session, as promised Marka spoke about LIGO results triggered by em observations. Note again that the S5 run has been operating at design sensitivity for some time now. Triggered events include gamma ray bursters, short hard GRBs and neutrinos. 39 GRBs were checked during the S2, S3 and S4 runs with a bandwidth of 40 to 2000 Hz. With the longer S5 run, 157 GRBs were checked from Nov 2005 to Mar 2007. For 70% of these events 2 detectors were in operation and for 40% there were three. For soft gamma ray flares such as SGR 1806-20 from Dec 2004, at a distance of around 10 kpc and energy around 10^46 erg, there were signatures for quasi-periodic signals in satellite observations, but no gravitational waves detected. Upper limits are beginning to look interesting.

The new, preliminary S5 result of most interest is for GRB 070201 in the galaxy M31. Images show the source region overlapping the spiral arms of M31. This burst duration was around 0.15 sec with a secondary pulse of 0.08 sec, and it was observed using two Hanford LIGO detectors. No GWs detected. The conclusion is that it is quite unlikely the source can be associated to M31 at all, and an upcoming paper will include minimum distance estimates for the source (based on the assumption that gravitational waves exist).