//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8920 SUBJECT: GRB 090301: Swift detection of a burst DATE: 09/03/01 07:07:31 GMT FROM: David Palmer at LANL L. Vetere (PSU), C. Gronwall (PSU), J. A. Kennea (PSU), C. B. Markwardt (CRESST/GSFC/UMD), D. M. Palmer (LANL), T. Sakamoto (NASA/UMBC), M. H. Siegel (PSU) and M. C. Stroh (PSU) report on behalf of the Swift Team: At 06:55:55 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 090301 (trigger=344582). Swift could not slew to the burst due to its proximity to the Sun (34 degrees). The BAT on-board calculated location is RA, Dec 338.140, +26.642 which is RA(J2000) = 22h 32m 34s Dec(J2000) = +26d 38' 32" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex multiple-peak structure with a duration of about 50 sec. The peak count rate was ~20,0000 counts/sec (15-350 keV), at ~23 sec after the trigger. Due to an observing constraint, Swift cannot slew to the BAT position. There will thus be no XRT or UVOT data for this trigger. The source will become observable again after April 15th. Burst Advocate for this burst is L. Vetere (vetere AT astro.psu.edu). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8923 SUBJECT: GRB 090301A: Swift-BAT refined analysis DATE: 09/03/01 17:22:50 GMT FROM: Scott Barthelmy at NASA/GSFC E. E. Fenimore (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. N. Ukwatta (GWU), L. Vetere (PSU) (i.e. the Swift-BAT team): Using the data set from T-61 to T+242 sec from the recent telemetry downlink, we report further analysis of BAT GRB 090301A (trigger #344582) (Vetere, et al., GCN Circ. 8920). The BAT ground-calculated position is RA, Dec = 338.142, 26.639 deg, which is RA(J2000) = 22h 32m 34.2s Dec(J2000) = +26d 38' 19.0" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 35%. The mask-weighted light curve shows a complex of overlapping and separated peaks starting at ~T-20 sec and ending some time after T+86 sec at which time the burst location went ouf out the BAT FOV when Swift slewed to the next planned target. Given that the burst location will not come out of the Sun observing consrtaint until after April 15, we will not have any further data on this burst. T90 (15-350 keV) is 41.0 +- 2.2 sec (estimated error including systematics). The time-averaged spectrum from T-17.0 to T+72.2 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.08 +- 0.12, and Epeak of 343.3 +- 328.8 keV (chi squared 37.39 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 2.3 +- 0.03 x 10^-5 erg/cm2 and the 1-sec peak flux measured from T+23.07 sec in the 15-150 keV band is 18.7 +- 0.6 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.25 +- 0.03 (chi squared 43.70 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/344582/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8924 SUBJECT: Konus-Wind observation of GRB 090301A DATE: 09/03/02 14:56:38 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report: The bright long GRB 090301A (Swift-BAT trigger #344582: Vetere et al., GCN 8920; Fenimore et al., GCN 8923) triggered Konus-Wind at T0=24949.694 s UT (06:55:49.694). The burst light curve shows a multipeaked structure with a duration of ~50 s, followed by a weak tail marginally seen up to ~T0+200 s. As observed by Konus-Wind the burst had a fluence of (1.13 +/- 0.08)x10^-4 erg/cm2, and a 64-ms peak flux measured from T0+25.408 s of (1.51 +/- 0.23)x10^-5 erg/cm2/s (both in the 20 keV - 5 MeV energy range). The time-integrated spectrum of the burst (from T0 to T0+44.032 s) is well fitted (in the 20 keV - 5 MeV range) by GRB (Band) model for which: the low-energy photon index alpha = -0.87 +/- 0.05, the high energy photon index beta = -2.65(-0.47, +0.25), the peak energy Ep = 429(-32, +34) keV (chi2 = 77.5/76 dof). All the quoted errors are at the 90% confidence level. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB090301_T24949/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8929 SUBJECT: GRB 090301A: Suzaku WAM observation of the prompt emission DATE: 09/03/04 15:39:51 GMT FROM: Kazutaka Yamaoka at Aoyama Gakuin U T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo), Y. Hanabata, Y. Fukazawa, T. Takahashi, T. Uehara, C. Kira (Hiroshima U.), Y. Terada, M. Tashiro, Y. Urata, A. Endo, K. Onda, N. Kodaka, K. Morigami, T. Sugasahara, W. Iwakiri (Saitama U.), M. Ohno, M. Kokubun, M. Suzuki, T. Takahashi (ISAS/JAXA), K. Yamaoka, S. Sugita (Aoyama Gakuin U.), Y.E. Nakagawa, T. Tamagawa (RIKEN), E. Sonoda, M. Yamauchi, H. Tanaka, R. Hara, N. Ohmori, K. Kono, H. Hayashi (Univ. of Miyazaki), S. Hong (Nihon U.), N. Vasquez (Tokyo Tech), on behalf of the Suzaku WAM team, report: The bright long GRB 090301A (Swift/BAT trigger #344582; Fenimore et al., GCN 8923) triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 06:55:50.862 UT (=T0). The observed light curve shows a multi-peaked structure lasting from T0-2s to T0+48s with a duration (T90) of about 35 seconds. The fluence in 100 - 1000 keV was 6.9(-0.5, +0.1) x 10^-5 erg/cm^2. The 1-s peak flux measured from T0+27 was 14.8(+/-0.9) photons/cm^2/s in the same energy range. Preliminary result shows that the time-averaged spectrum from T0-2s to T0+48s is fitted by a GRB Band model as follows. the low-energy photon index alpha: -0.93 (-0.16, +0.18), the high-energy photon index beta: -2.82 (-0.74, +0.29), the break energy E0: 536 (-101, +131) keV, and the peak energy Epeak: 574 +/- 170 keV (chi^2/d.o.f = 68/56). Due to the high counting rate of this GRB, a 1% systematic error was added for low energy channels. All the quoted errors are at the 90% confidence level. The light curves for this burst are available at: http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html