From quai@cbatmpc.harvard.edu Wed Jun 3 19:04:01 1998 Return-Path: Received: [ from aip.de by abrixas.obs.aip.de (8.8.7/8.8.7) with SMTP id TAA01795 for ; Wed, 3 Jun 1998 19:04:01 +0200 (MET DST)] Received: from cfa.harvard.edu by marlowe (4.1/SMI-4.2-apr170795) id AA02255; Wed, 3 Jun 98 19:02:51 +0200 Received: from cbatmpc.harvard.edu (cbatmpc.harvard.edu [131.142.10.57]) by cfa.harvard.edu (8.8.5/8.7.3) with SMTP id NAA24176 for ; Wed, 3 Jun 1998 13:03:04 -0400 (EDT) Received: by cbatmpc.harvard.edu (SMI-8.6/SMI-SVR4) id NAA13274; Wed, 3 Jun 1998 13:02:32 -0400 Date: Wed, 3 Jun 1998 13:02:32 -0400 From: quai@cbatmpc.harvard.edu (IAUC mailing list) Message-Id: <199806031702.NAA13274@cbatmpc.harvard.edu> To: iau-circulars@aip.de Subject: IAUC 6929: SGR 1900+14 Status: RO Circular No. 6929 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science) URL http://cfa-www.harvard.edu/iau/cbat.html Phone 617-495-7244/7440/7444 (for emergency use only) SGR 1900+14 K. Hurley, Space Sciences Laboratory, on behalf of the Ulysses Gamma-Ray Burst Team; C. Kouveliotou, Universities Space Research Association, on behalf of the Gamma-Ray Observatory BATSE team; and E. Mazets and T. Cline, on behalf of the KONUS-WIND team, report: "This soft gamma-ray repeater has entered an extraordinary new phase of activity with a previously unobserved frequency and intensity of bursts. Activity began on May 26 and has continued at least through May 30. Triangulation with Ulysses and BATSE gives a preliminary annulus whose center is at R.A. = 21h58m18s, Decl. = -11o18'.4 (equinox 2000.0), and whose radius is 47.269 +/- 0.019 deg. This annulus includes the network synthesis error box (Hurley et al. 1994, Ap.J. 431, L31), the ROSAT source proposed as a possible quiescent x-ray counterpart to the soft repeater (Hurley et al. 1996, Ap.J. 463, L13), and the peculiar double M star system coincident with the ROSAT source (Vrba et al. 1996, Ap.J. 468, 225). As all these locations are mutually consistent, we conclude that the ROSAT source and M star system are indeed the counterparts to the soft gamma-ray repeater, and urge that observations at other wavelengths be undertaken immediately, while the source remains active. An image may be found at http://ssl.berkeley.edu/ipn3/sgr1900+14/." C. Kouveliotou, Universities Space Research Association; P. Woods, M. Kippen, and M. S. Briggs, University of Alabama in Huntsville; and K. Hurley, Space Sciences Laboratory, write: "On May 30, BATSE triggered on an extremely intense outburst from this source that comprised at least 38 bursts of varying intensity and duration; the series of bursts started at May 30.37759 UT and lasted for about 350 s. The peak flux of each of the three major bursts in the series is 1.1 x 10E-4 erg cmE-2 sE-1 (between 25 and 300 keV, integrated for 128 ms). Assuming a distance of about 12 kpc for SGR 1900+14 (Vrba et al. 1996, Ap.J. 468, 225), this corresponds to a luminosity of about 2 x 10E42 ergs/s for each burst. This bunching of emission is very similar to the behavior of SGR 1806-20, as detected with the Rossi X-Ray Timing Explorer in 1996 (IAUC 6503). Overall, between May 26 and June 1, we have detected over 50 bursts from SGR 1900+14. The frequency and intensity of emissions are unlike any previously seen behavior from this source. We strongly encourage follow-up observations at infrared and radio wavelengths, while the source is still active." (C) Copyright 1998 CBAT 1998 June 3 (6929) Daniel W. E. Green