THIS FILE CHANGES WITH TIME -- HIT THE RELOAD BUTTON NOW! ///////////////////////////////////////////////////////////////////// SGR 1900+14 ///////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 94 SUBJECT: SGR1900+14 DATE: 98/06/03 01:03:48 GMT FROM: Kevin Hurley at UCBerkeley/SSL 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 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 (equinox 2000.0) R.A. = 21h58m18s, Decl. = -11o18'.4, and whose radius is 47.269 +/- 0.019 deg. This annulus includes the network synthesis error box (Hurley et al. ApJ 431, L31, 1994), the ROSAT source proposed as a possible quiescent X-ray counterpart to the soft repeater (Hurley et al. ApJ 463, L13, 1996), and the peculiar double M star system coincident with the ROSAT source (Vrba et al. ApJ 468, 225, 1996). 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 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, M.S. Briggs, University of Alabama in Huntsville, K. Hurley, Space Sciences Laboratory, report: "On May 30th, 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 32624 s UT, and lasted for about 350s. The peak flux of each of the three major bursts in the series is 1.1x10e-4 ergs/cm^2 s (between 25-300 keV, integrated for 128 ms). Assuming a distance of about 12 kpc for SGR 1900+14 (F. Vrba et al., ApJ 468, 225 1996), this corresponds to a luminosity of about 2x10e42 ergs/s for each burst. This bunching of emission is very similar to the behaviour of SGR 1806-20, as detected with the Rossi X-Ray Timing Explorer in 1996 (C. Kouveliotou, et al, IAUC 6503). Overall, between May 26 and June 1st, we have detected over 50 bursts from SGR 1900+14. The frequency and intensity of emissions are unlike any previously seen behaviour from this source. We strongly encourage follow up observations in infra-red and radio wavelengths, while the source is still active." These messages are citeable. ///////////////////////////////////////////////////////////////////// [Operators Note: This is the 2nd distribution -- see explanation below.] TITLE: GCN GRB OBSERVATION REPORT NUMBER: 95 SUBJECT: SGR1900+14 DATE: 98/06/03 01:40:08 GMT FROM: Kevin Hurley at UCBerkeley/SSL 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 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 (equinox 2000.0) R.A. = 21h58m18s, Decl. = -11o18'.4, and whose radius is 47.269 +/- 0.019 deg. This annulus includes the network synthesis error box (Hurley et al. ApJ 431, L31, 1994), the ROSAT source proposed as a possible quiescent X-ray counterpart to the soft repeater (Hurley et al. ApJ 463, L13, 1996), and the peculiar double M star system coincident with the ROSAT source (Vrba et al. ApJ 468, 225, 1996). 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 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, M.S. Briggs, University of Alabama in Huntsville, K. Hurley, Space Sciences Laboratory, report: "On May 30th, 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 32624 s UT, and lasted for about 350s. The peak flux of each of the three major bursts in the series is 1.1x10e-4 ergs/cm^2 s (between 25-300 keV, integrated for 128 ms). Assuming a distance of about 12 kpc for SGR 1900+14 (F. Vrba et al., ApJ 468, 225 1996), this corresponds to a luminosity of about 2x10e42 ergs/s for each burst. This bunching of emission is very similar to the behaviour of SGR 1806-20, as detected with the Rossi X-Ray Timing Explorer in 1996 (C. Kouveliotou, et al, IAUC 6503). Overall, between May 26 and June 1st, we have detected over 50 bursts from SGR 1900+14. The frequency and intensity of emissions are unlike any previously seen behaviour from this source. We strongly encourage follow up observations in infra-red and radio wavelengths, while the source is still active." These messages are citeable. [GCN Operator's Note: The process table on the machine used by the GCN Circular system exceeded the maximum number of processes. This caused about 15 e-mails to be aborted. This re-invoking the mailing will fix the omission (with about a 30 minute extra delay). Since it is impossible to determine to the exact person in the list when the overflow started and when it stopped, a few of you will be receiving a second copy of this circular so as to make sure that everyone receives at least one copy -- my apologies for the duplication. Also, the re-invokation results in a Circular number (=95) different from the number for the original mailing (=94). Pepole should use the original number (94) when making citations. The GCN Circular distribution program has been fixed to prevent this problem from recurring.] ///////////////////////////////////////////////////////////////////// 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 ///////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 97 SUBJECT: SGR 1900+14 DATE: 98/06/05 00:43:43 GMT FROM: Josh Bloom at CIT SGR 1900+14 IR Observations B. R. Oppenheimer, J. S. Bloom, S. S. Eikenberry, and K. Matthews (Caltech) report: "We have obtained narrowband 2.2 micron images of the proposed infrared counterpart to SGR 1900+14 (Vrba et al. 1996, Ap.J. 468, 225) at June 3.486 UT, 4.1 days after the recent bursting activity reported by Hurley et al. and Kouveliotou et al. (IAUC 6929). Differential photometry of stars "A" and "B" (the double M -stars) and star "C" of Vrba et al. show A-B=0.4 +-0.1 mag and A-C=4.5+-0.2 mag, consistent with the measurements of Vrba et al. Over the course of 10 minutes (ten separate frames) no variability was detected in the double M-stars to a limit of 0.1 mag." This report may be cited. ///////////////////////////////////////////////////////////////////// Circular No. 6933 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 B. R. Oppenheimer, J. S. Bloom, S. S. Eikenberry, and K. Matthews, California Institute of Technology, communicate: "We have obtained narrowband 2.2-micron images of the proposed infrared counterpart to SGR 1900+14 (Vrba et al. 1996, Ap.J. 468, 225) on June 3.486 UT, 4.1 days after the recent bursting activity reported on IAUC 6929. Differential photometry of stars 'A' and 'B' (the double M stars) and star 'C' of Vrba et al. yields m_A-m_B = +0.4 +/- 0.1 and m_A-m_C = +4.5 +/- 0.2 mag, consistent with the measurements of Vrba et al. Over the course of 10 min (ten separate frames), no variability was detected in the double M stars to a limit of 0.1 mag." (C) Copyright 1998 CBAT 1998 June 5 (6933) Daniel W. E. Green ///////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 120 SUBJECT: SGR1900+14 field optical observations DATE: 98/06/30 17:05:16 GMT FROM: Arne A Henden at USNO/USRA A. Henden, C. Luginbuhl and F. Vrba (U.S. Naval Observatory Flagstaff Station) report that they have obtained extensive I-band and J-band observations of the near-IR sources and surrounding field associated with SGR1900+14 both before and after the recent onset of activity. None of the observations coincide with bursts detected by BATSE, and no unusual photometric behavior has been detected though reductions are ongoing. A new eclipsing binary has been detected nearby, however, at RA 19:07:16.85 DEC +09:18:50.4 (J2000), about 39.0 arcseconds SE of the M supergiant pair. The binary is about I=19.1 out of eclipse, and has been observed through several eclipses of about 0.4mag depth. The period is either about 1.07day or some integer fraction. This binary appears as the star labelled 'J' in Figure 1 of Vrba et. al. ApJ 468:225 (1996). We bring this star to the attention of other observers in the hope that it not send anyone on a wild goose chase if it is detected as a variable in observations of this gamma-ray burst location. This message is quotable in publications. ///////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 121 SUBJECT: Radio observations of SGRs DATE: 98/07/01 17:10:46 GMT FROM: Dale A Frail at NRAO D. A. Frail, National Radio Astronomy Observatory and S. R. Kulkarni, California Institute of Technology report: The recent renewed activity from SGR1900+14 (GCN #94) and the newly-discovered SGR1627-41 (GCN #107) prompted VLA radio observations at 8.46 GHz on 1998 June 25. For SGR1900+14 we observed a field centered on the proposed X-ray/infrared counterpart (Hurley et al. ApJ, 463, L13, 1996, Vrba et al. ApJ, 468, 225, 1996). For SGR1627-41 we observed the 95 arcsec diameter supernova remnant CTB33 (IAU Circ. 6948), most recently studied by Sarma, Goss, Green & Frail (ApJ, 483, 335, 1997). The synthesized beam was approximately 1 arcsec. The interferometer is insensitive to extended structure on angular scales larger than 20 arcsec. No point sources were visible above 200 microJy and 345 microJy (4-sigma) for the SGR1900+14 and SGR1627-41, respectively. This report can be cited. ///////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 153 SUBJECT: SGR1900+14, BeppoSAX-GRBM observations DATE: 98/09/01 15:49:39 GMT FROM: Marco Feroci at IAS/CNR Frascati SGR 1900+14 M. Feroci, P. Soffitta, E. Costa, Istituto di Astrofisica Spaziale, CNR, Rome, and F. Frontera, Istituto Tecnologie e Studio Radiazioni Extraterrestri, CNR, Bologna, on behalf of the BeppoSAX/GRBM team, and M. Tavani, Istituto di Fisica Cosmica, CNR, Milano, and Columbia Astrophysics Laboratory, New York, report: "The Gamma-Ray Burst Monitor (GRBM) onboard BeppoSAX was triggered by the event reported by Cline et al. (IAUC 7002) on Aug. 27.4321259. The event showed a fast rise (<1s) and an exponential-like decay, lasting more than 300s. The event was observed at an off-set angle of about 56 degrees from the axis of GRBM unit 1, and showed a peak intensity in (40-700 keV) of about 64000 c/s. The event was clearly detected above 100 keV. A preliminary analysis shows that the spectrum is hard during the initial 1s, followed by a sudden softening. Subsequent spectral evolution shows a progressive hardening. The near-5s periodicity reported by Cline et al. (IAUC 7002) is evident in the GRBM data for the entire duration of the event. In addition, starting from about 35s after the event onset, the GRBM clearly detected a periodic pattern of subpulses for each near-5s oscillation. The repetitive pattern is made of four subpulses of period near-1s. More detailed temporal and spectral analyses are in progress."