//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9963 SUBJECT: GRB 090929B: Swift detection of a burst DATE: 09/09/29 10:37:12 GMT FROM: David Palmer at LANL C. Pagani (PSU), A. P. Beardmore (U Leicester), S. Campana (INAF-OAB), V. D'Elia (ASDC), C. Gronwall (PSU), D. Grupe (PSU), C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC), N. P. M. Kuin (MSSL), J. Mao (INAF-OAB), P. T. O'Brien (U Leicester), J. P. Osborne (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), P. Romano (INAF-IASFPA), B. Sbarufatti (INAF-IASFPA), T. N. Ukwatta (GSFC/GWU) and L. Vetere (PSU) report on behalf of the Swift Team: At 10:09:07 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 090929B (trigger=371050). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 117.705, -0.632 which is RA(J2000) = 07h 50m 49s Dec(J2000) = -00d 37' 55" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with most activity in multiple peaks from T-10 sec to T+50 s, and additional peaks at T+150 sec, during the XRT observations. The peak count rate was ~7000 counts/sec (15-350 keV), at ~40 sec after the trigger. The XRT began observing the field at 10:10:31.3 UT, 84.1 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 117.7202, -0.6574 which is equivalent to: RA(J2000) = 07h 50m 52.84s Dec(J2000) = -00d 39' 26.6" with an uncertainty of 5.3 arcseconds (radius, 90% containment). This location is 106 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 1.49e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 97 seconds with the White filter starting 93 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.07. We note there is a bright (10th mag) star less than 2 arcsec from the XRT position which complicates the analysis of the UVOT data. Burst Advocate for this burst is C. Pagani (pagani 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: 9965 SUBJECT: Correction: GRB 090929B: Enhanced Swift-XRT position DATE: 09/09/29 14:09:34 GMT FROM: Kim Page at U.of Leicester K.L. Page (U. Leicester) reports on behalf of the Swift-XRT team: GCN Circ. 9964 referred to GRB 090929 when, in fact, the position given is for GRB 090929B (GCN Circ. 9963). The correct text should read Using 2438 s of XRT Photon Counting mode data and 2 UVOT images for GRB 090929B, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 117.72015, -0.65764 which is equivalent to: RA (J2000): 07h 50m 52.84s Dec (J2000): -00d 39' 27.5" with an uncertainty of 1.8 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). We apologise for any confusion. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9967 SUBJECT: GRB 090929B: RAPTOR Discovery of Optical Counterpart DATE: 09/09/29 16:46:34 GMT FROM: James Wren at LANL J. Wren, W.T. Vestrand, P.R. Wozniak, H. Davis, B. Norman of Los Alamos National Laboratory report: The RAPTOR telescope system responded to Swift trigger 371050 (Pagani et al., GCN 9963) under good observing conditions. Our narrow-field instruments began observing the location at 10:20:53.37 UTC, 11.77 minutes after the initial BAT trigger. Our initial images show an R~16.8 optical counterpart at the enhanced XRT location (Page et al., GCN 9965). The object fades steadily reaching R~18.0 at 10:50 UTC. Our unfiltered images were calibrated against the USNO-B1 R-band. Unfortunately, an 11th magnitude star is only 19 arcseconds away, limiting our photometric accuracy. Further analysis is ongoing. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9969 SUBJECT: GRB 090929B: Swift/UVOT Observations DATE: 09/09/29 19:13:57 GMT FROM: Peter Curran at MSSL P.A. Curran (MSSL-UCL), F. Marshall (GSFC), S. Holland (GSFC) and C. Pagani (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 090929B 94s after the BAT trigger (Pagani et al., GCN Circ. 9963). No optical afterglow is detected in the b, u or uvw2 UVOT exposures. There is a detection in the white filter, consistent with the enhanced XRT position (Goad et al. GCN 9964, Page et al. GCN 9965), the proposed optical counterpart (Wren et al. GCN 9967) and a USNO catalogued star (R2=19.3). Since the photometry is contaminated by a bright (R = 9.5), near-by star, we cannot determine the nature of the source at this time. Preliminary magnitudes and 3-sigma upper limits using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for the initial exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag ---------------------------------------------------------------- white 94 4032 292 18.7 +/- 0.5 b 3627 3827 197 >20.5 u 3422 3622 197 >20.3 uvw2 4038 4224 183 >20.3 The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.07 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9970 SUBJECT: GRB 090929B: Skynet/DSO Observations DATE: 09/09/29 20:28:10 GMT FROM: Josh Haislip at U.North Carolina J. Haislip, D. Reichart, A. Smith, D. Caton, L. Hawkins, K. Ivarsen, M. Schubel, A. LaCluyze, A. Foster, J. Moore, A. Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. Nysewander report: Skynet observed the Swift/BAT localization of GRB 090929B (Pagani et al., GCN 9963) with the 14" Dark Sky Observatory telescope in North Carolina beginning 12.0 minutes after the trigger in I. We do not detect the afterglow (Pagani et al., GCN 9963, Wren et al., GCN 9967) within the enhanced Swift/XRT localization (Goad et al., 9964; Page, GCN 9965). However, the nearby I = 9.07 mag (USNO B1) star complicates photometry. mean 1-sig. 1-sig. time 3-sig. sys. stat. since lim. cal. cal. cal. trig. tel. exp. fil. mag. stars unc. unc. (h) (# x s) (mag) (mag) 12.0 DSO-14 1 x 80 I 17.1 183 USNO B1 0.400 0.001 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9971 SUBJECT: GRB 090929B: Gemini-N upper limits DATE: 09/09/29 21:12:50 GMT FROM: Antonino Cucchiara at PSU A. Cucchiara, D. B. Fox (PSU), N. Tanvir (U. Leicester), E. Berger (Harvard U.) and A. Levan (U. Warwick) report: On September 29.58 UT we observed the field of GRB 090929B (Pagani et al. GCN 9963) with Gemini-North + NIRI. We took a sequence of YJHK bands images under twilight conditions. No clear afterglow candidate has been found in the XRT refined error circle (GCN 9964 and 9965) to the following limits (3-sigma): J > 21.10 mag H > 19.53 mag K > 18.06 mag Our limits are estimated using detected 2MASS objects at comparable distance to the bright star (R = 9.5) which is located near the XRT error circle. We note the presence of a USNO catalogued star inside the refined error circle; the above limits are exclusive of that star. We thank the Gemini staff for performing these observations, in particular Ricardo Schiavon. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9973 SUBJECT: GRB 090929B: Swift-XRT refined analysis DATE: 09/09/30 01:40:54 GMT FROM: Claudio Pagani at PSU/Swift-XRT C. Pagani and L. Vetere (PSU) report on behalf of the Swift-XRT team: We have analysed 3.7 ks of XRT data for GRB 090929B (Pagani et al. GCN Circ. 9963), from 90 s to 16.3 ks after the BAT trigger. The first orbit of data was entirely taken in Windowed Timing (WT) mode for a total of 100 s. The remaining orbits are in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Page (GCN. Circ 9965). The light curve shows intense flaring activity during the first orbit with the strongest emission at approximately 180 counts s^-1 at T+150 s, during a peak also detected by the BAT (GCN Circ. 9963). The following orbits can be modeled with a broken power-law decay with an shallow phase of index of alpha=0.5 (+1.0, -0.6) followed by a steeper decay of index alpha=1.2+/-0.3 after ~T+5.6 ks. A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.68 (+/-0.05). The best-fitting absorption column is 2.2 (+/-0.1) x 10^21 cm^-2, in excess of the Galactic value of 5.4 x 10^20 cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index of 2.01 (+0.18, -0.17) and a best-fitting absorption column of 1.6 (+0.5, -0.4) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.1 x 10^-11 (5.7 x 10^-11) erg cm^-2 count^-1. If the light curve continues to decay with a power-law decay index of 1.2, the count rate at T+24 hours will be 0.015 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 6.1 x 10^-12 (8.6 x 10^-12) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00371050. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9975 SUBJECT: Konus-Wind observation of GRB 090929B DATE: 09/09/30 13:30:14 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 long GRB 090929B (Swift-BAT trigger #371050: Pagani et al., GCN 9963) triggered Konus-Wind at T0=36565.377 s UT (10:09:25.377). The burst light curve shows a multipeaked structure with a total duration of ~20 s. As observed by Konus-Wind the burst had a fluence of (1.16 +/- 0.12)x10^-5 erg/cm2, and a 256-ms peak flux measured from T0+16.208 s of (3.80 +/- 0.90)x10^-6 erg/cm2/s (both in the 20 keV - 1 MeV energy range). The time-integrated spectrum of the burst (from T0 to T0+16.640 s) is well fitted (in the 20 keV - 1 MeV range) by GRB (Band) model for which: the low-energy photon index alpha = -0.41 (-0.77, +1.16), the high energy photon index beta = -1.82(-0.59, +0.24), the peak energy Ep = 282(-78, +169) keV (chi2 = 52.4/59 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/GRB090929_T36565/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9979 SUBJECT: GRB 090929B, Swift-BAT refined analysis DATE: 09/09/30 21:04:27 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), C. B. Markwardt (GSFC/UMD), C. Pagani (PSU), 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) (i.e. the Swift-BAT team): Using the data set from T-239 to T+691 sec from the recent telemetry downlink, we report further analysis of BAT GRB 090929 (trigger #371050) (Pagani, et al., GCN Circ. 9963). The BAT ground-calculated position is RA, Dec = 117.712, -0.645 deg which is RA(J2000) = 07h 50m 50.9s Dec(J2000) = -00d 38' 41.2" with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 63%. The mask-weighted lightcurve shows many peaks interspersed with intervals with no detected flux, from T-10 to T+380 sec when the source left the coded field of view due to a observing constraint. There may have been small and/or low-energy peaks beyond this time. The largest peak was at about T+30 to T+40 sec. T90 (15-350 keV) was 360 +- 20 sec (estimated error including systematics). The time-averaged spectrum from T-9.8 to T+371.0 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.85 +- 0.08. The fluence in the 15-150 keV band is 5.9 +- 0.3 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+30.67 sec in the 15-150 keV band is 3.3 +- 0.2 ph/cm2/sec. 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/371050/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9993 SUBJECT: GRB 090929B: Suzaku WAM observation of the prompt emission DATE: 09/10/05 09:02:34 GMT FROM: Norisuke Ohmori at Miyazaki U N. Ohmori, E. Sonoda, K. Kono, H. Hayashi, A. Daikyuji, Y. Nishioka, K. Noda, M. Yamauchi (Univ. of Miyazaki), K. Yamaoka (Aoyama Gakuin U.), Y. Hanabata, T. Uehara, T. Takahashi, Y. Fukazawa (Hiroshima U.), M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA), W. Iwakiri, M. Tashiro, Y. Terada, A. Endo, K. Onda, T. Sugasahara (Saitama U.), Y. Urata (NCU), T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo), Y. E. Nakagawa, T. Tamagawa (RIKEN), S. Hong (Nihon U.), S. Sugita (Nagoya U.), N. Vasquez (Tokyo Tech.), on behalf of the Suzaku WAM team, report: The long GRB 090929B (Swift-BAT trigger #371050; Pagani et al., GCN 9963, Krimm et al. GCN 9979) was detected by the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 10:09:23.633 UT (=T0). The observed light curve shows a multi-peaked structure, starting at T0-2 s and ending at T0+20 s, with a total duration (T90) of about 18 s. The fluence in 100 - 1000 keV was (3.92 ± 0.63) x 10-6 erg/cm2. The 1-s peak flux measured from T0+1 s was 1.42 (-0.25. +0.24) photons/cm2/s in the same energy range. Preliminary result shows that the time-averaged spectrum from T0-2 s to T0+20 s is well fitted by a single power-law with a photon index of 1.96 (-0.17, +0.20) (chi2/d.o.f = 23.4/27). All the quoted errors are at statistical 90% confidence level, in which the systematic uncertainties are not included. The light curves for this burst will be available at: http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/untrig/grb_table.html