TITLE: GCN GRB OBSERVATION REPORT NUMBER: 931 SUBJECT: IPN Status Report DATE: 01/02/13 19:10:33 GMT FROM: Kevin Hurley at UCBerkeley/SSL As many of you are no doubt aware, the Near Earth Asteroid Rendezvous mission executed a controlled descent to the surface of the asteroid Eros on February 12, bringing the mission to a successful end. However, this has also deprived the 3rd Interplanetary Network of the second distant point which is required to produce small error boxes. The network now consists of Ulysses, in heliocentric orbit, BeppoSAX (GRBM), HETE-II, and RXTE, in low earth orbit, and Konus-Wind, at the L1 Lagrange point. In this configuration, the IPN can produce (as it did prior to NEAR), a) single annuli (using Ulysses and one other spacecraft), which will help reduce the sizes of the error boxes derived from HETE-II, RXTE, and the BeppoSAX WFC and NFI, and b) long, narrow error boxes (using Ulysses, Konus, and a near-Earth spacecraft). In general, our policy will be NOT to issue GCN notices for the bursts detected by the IPN in this mode unless 1) they are imaged by BeppoSAX, HETE-II, or RXTE, 2) they are very unusual in some sense, 3) they are suspected to originate from known or new soft gamma repeaters, or 4) potential users of such notices notify us of their requirements. (We do, however, intend to triangulate these events and produce a catalog of them eventually. We will also begin work immediately on a catalog of NEAR bursts.) The Mars Odyssey '01 mission, to be launched in April, has two independent gamma-ray burst detection systems. Because the mission goes farther from Earth than NEAR, and because the detection systems have better time resolution, this rejuvenated network promises to perform better than the old one. Due to financial constraints, there is still some uncertainty about the duty cycles of these systems during the 9 month cruise phase to Mars. (Although once they are in orbit, they are expected to operate continuously for one Mars year, i.e. through 2003.) We look forward to continuing to issue small error box notices, perhaps as soon as a few months from now. Kevin Hurley (on behalf of the Ulysses GRB team) Thomas Cline (on behalf of the NEAR GRB team) Scott Barthelmy (on behalf of the GCN)