TITLE: GCN CIRCULAR NUMBER: 6408 SUBJECT: GRB 070512: IPN localization and Konus spectrum of a bright burst DATE: 07/05/14 19:01:07 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, and T. Cline on behalf of the Konus-Wind team, K. Hurley and T. Cline, on behalf of the Mars Odyssey GRB team, I. Mitrofanov, A. Kozyrev, M. Litvak, A. Sanin, V. Tret'yakov and A. Parshukov, on behalf of the HEND-Odyssey GRB team, W. Boynton, C. Fellows, K. Harshman, C. Shinohara and R. Starr, on behalf of the GRS-Odyssey GRB team, J. Cummings, S. Barthelmy, N. Gehrels, and H. Krimm, on behalf of the Swift-BAT team, A bright GRB triggered Konus-Wind at 2007-05-12 T0=21972.572 s UT (06:06:12.572). It was also observed by Mars Odyssey (HEND and GRS), and Swift-BAT. The burst was outside of the field of view of Swift-BAT, so it was not imaged. The burst light curve shows a single smooth pulse with a duration of ~2 sec, followed by a weak tail seen up to T-T0 ~10 sec. There is substantial time lag between light curve in different Konus-Wind bands. It was triangulated to the MO-Wind annulus centered at RA=357.861 (23h 51m 27s) Dec=-2.565 (-2d 33' 55"), whose radius is 87.897 +/- 0.035 deg (3 sigma). The Wind-Swift annulus constrains the arrival direction to the long 3-sigma error box (portion of the annulus) with corners: --------------------------------------------------- RA, deg Dec, deg (J2000) --------------------------------------------------- 269.113 (17h 56m 27s) -20.440 (-20d 26' 25") 269.181 (17h 56m 43s) -20.642 (-20d 38' 31") 268.735 (17h 54m 56s) -30.959 (-30d 57' 32") 268.823 (17h 55m 18s) -30.761 (-30d 45' 41") --------------------------------------------------- The area of the box is 0.361 sq. deg. We note that this error box is consistent with the direction of the Galactic bulge. We are waiting for MESSENGER data to reduce the size of the error box. Preliminary analysis of the Konus-Wind data yields a burst fluence of 2.86(-0.12, +0.10)x10^-5 erg/cm2 (in the 20 keV - 1 MeV range). The time-integrated spectrum of the burst (from T0 to T0+9.472 s) can be fitted (in the 20 keV - 1 MeV range) by GRBM (Band) model for which: the low-energy photon index is alpha = -0.68(-0.18, +0.19), the high energy photon index beta = -2.65 (-0.46, +0.20), the peak energy Ep = 191(-18, +23) keV (chi2 = 68/59 dof). So the burst cannot definitely be placed in either the short or long GRB class. All the quoted errors are at the 90% confidence level. The Konus-Wind light curve of this GRB is available at http://www.ioffe.rssi.ru/LEA/GRBs/GRB070512_T21972/