GRB090812A

This page lists all entries on GRB090812A in GRBweb

Summary IPN Swift GCN 9768 GCN 9769 GCN 9770 GCN 9771 GCN 9772 GCN 9773 GCN 9774 GCN 9775 GCN 9776 GCN 9777 GCN 9778 GCN 9779 GCN 9780 GCN 9814 GCN 9816 GCN 9821 GCN 9999

Summary table
Variable Value Source
T0 6:02:08 UTC GCN_circulars,Swift Det
ra 353.2022° Swift
decl -10.6048° Swift
pos_error 1.01e-04° Swift
T90 66.7 s Swift
T90_start 6:02:08 UTC Swift
fluence 5.80e-06 erg/cm² Swift
redshift 2.4520 GCN_circulars,Other
T100 66.7 s
GBM_located False
mjd 55055.25148148148 GCN_circulars,Swift Det
IPN table
GRB_name GRB090812A
ra 353.1958°
decl -10.6000°
pos_error 5.00e-02°
redshift 2.4520
Swift table
GRB_name GRB090812A
t_trigger 6:02:08 UTC
ra 353.2022°
decl -10.6048°
pos_error 1.01e-04°
T90 66.7 s
fluence 5.80e-06 erg/cm²
redshift 2.4520
GCN 9768 table
GRB_name GRB090812A
GCN_number 9768
Detection_method Swift Det
t_trigger 6:02:08 UTC
ra 353.1940°
decl -10.5950°
Circular_text TITLE: GCN CIRCULAR NUMBER: 9768 SUBJECT: GRB 090812: Swift detection of a burst with an optical counterpart DATE: 09/08/12 06:20:46 GMT FROM: David Palmer at LANL M. Stamatikos (NASA/ORAU), J. R. Cummings (NASA/UMBC), P. A. Evans (U Leicester), C. Gronwall (PSU), C. Guidorzi (U Ferrara), C. B. Markwardt (CRESST/GSFC/UMD), P. T. O'Brien (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL) and R. L. C. Starling (U Leicester) report on behalf of the Swift Team: At 06:02:08 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 090812 (trigger=359711). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 353.194, -10.595 which is RA(J2000) = 23h 32m 47s Dec(J2000) = -10d 35' 39" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a triple-peaked structure with a duration of about 70 sec. The peak count rate was ~6500 counts/sec (15-350 keV), at ~25 sec after the trigger. The XRT began observing the field at 06:03:25.7 UT, 76.8 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 353.20133, -10.60457 which is equivalent to: RA(J2000) = 23h 32m 48.32s Dec(J2000) = -10d 36' 16.5" with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 43 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 2.26e+20 cm^-2 (Kalberla et al. 2005). The initial flux in the 2.5 s image was 4.95e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 250 seconds with the U filter starting 298 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 23:32:48.53 = 353.20222 DEC(J2000) = -10:36:17.3 = -10.60481 with a 90%-confidence error radius of about 0.78 arc sec. This position is 5.1 arc sec. from the center of the XRT error circle. The estimated magnitude is 18.62 with a 1-sigma error of about 0.16. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02. Burst Advocate for this burst is M. Stamatikos (michael AT milkyway.gsfc.nasa.gov). 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.)
GCN 9769 table
GRB_name GRB090812A
GCN_number 9769
Detection_method Other
ra 353.2023°
decl -10.6047°
Circular_text TITLE: GCN CIRCULAR NUMBER: 9769 SUBJECT: GRB 090812: P60 Confirmation of Optical Afterglow DATE: 09/08/12 06:53:20 GMT FROM: S. Bradley Cenko at Caltech S. B. Cenko (UC Berkeley) reports on behalf of a larger collaboration: We have imaged the field of GRB090812 (Stamatikos et al., GCN 9768) with the automated Palomar 60 inch telescope. Observations were obtained in the Sloan r', i', and z' filters beginning at 6:34 UT (~ 2.5 minutes after the burst). Near the XRT afterglow we detect a point source at coordinates (J2000): RA: 23:32:48.55 Dec: -10:36:17.0 with an estimated uncertainty of ~ 0.3" in each coordinate. This is consistent with the position reported by the UVOT. We measure the following magnitudes for the source, calculated with respect to the SDSS DR7: Time (UT mid-point) Exposure (s) Filter Magnitude ----------------------------------------------------------------------- 06:05:02 60 r' 16.18 06:06:27 60 i' 16.39 06:09:28 60 r' 17.30 06:10:43 60 i' 17.34 The fading nature confirms this is the afterglow of GRB090812. Further observations are planned.
GCN 9770 table
GRB_name GRB090812A
GCN_number 9770
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 9770 SUBJECT: GRB 090812: Liverpool Telescope afterglow confirmation DATE: 09/08/12 07:19:41 GMT FROM: Cristiano Guidorzi at Ferrara U,Italy R.J. Smith (Liverpool JMU), A. Gomboc (U. Ljubljana), C. Guidorzi (U. Ferrara), C.G. Mundell, I.A. Steele, A. Melandri, S. Kobayashi, C.J. Mottram, D.F. Bersier, Z. Cano (Liverpool JMU) report on behalf of a large collaboration: On 2009 August 12 at 06:03:54 UT the 2-m Liverpool Telescope automatically began observing the Swift GRB 090812 (Stamatikos et al., GCN Circ. 9768) using the r' and i' filters. We clearly detected the fading optical afterglow reported by Swift-UVOT and P60 (Cenko et al. GCN Circ. 9769) with the following values: Mid Time Delay from BAT Total Exp Filter Mag (UT) trigger (s) (s) ---------------------------------------------------------- 06:03:59 111 10 r' 15.51 +- 0.04 06:06:26 258 10 r' 16.60 +- 0.10 ---------------------------------------------------------- Magnitudes have been calibrated from nearby SDSS stars.
GCN 9771 table
GRB_name GRB090812A
GCN_number 9771
Detection_method Other
redshift 2.4520
Circular_text TITLE: GCN CIRCULAR NUMBER: 9771 SUBJECT: GRB 090812 VLT redshift DATE: 09/08/12 09:02:26 GMT FROM: Antonio Deugarte at IAA-CSIC A. de Ugarte Postigo (INAF-OAB), J. Gorosabel (IAA-CSIC), J.P.U. Fynbo (DARK/NBI), K. Wiersema and N. Tanvir (Leicester) report on behalf of a larger collaboration We have observed the afterglow of GRB 090812 (Stamatikos et al. GCNC 9768) using FORS2 at the VLT (Paranal observatory) starting at 06:54 UT (52min after the burst). In the spectrum we detect strong absorption lines, including Ly-alpha, SiII, SiII*, CII, SiIV, CIV, SiII, AlII, AlIII, FeII, ZnII, MnII and TiII at a common redshift of 2.452 which we identify as the redshift of the GRB. We also detect absorption lines from an unidentified intervening system. Further analysis is ongoing. We acknowledge the excellent support from Paranal staff, in particular Jonathan Smoker, Cedric Ledoux and Karla Aubel.
GCN 9772 table
GRB_name GRB090812A
GCN_number 9772
Detection_method Swift-XRT Det
ra 353.2022°
decl -10.6049°
Circular_text TITLE: GCN CIRCULAR NUMBER: 9772 SUBJECT: GRB 090812: Enhanced Swift-XRT position DATE: 09/08/12 10:25:05 GMT FROM: Phil Evans at U of Leicester M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team. Using 456 s of XRT Photon Counting mode data and 1 UVOT images for GRB 090812, 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 = 353.20225, -10.60489 which is equivalent to: RA (J2000): 23h 32m 48.54s Dec (J2000): -10d 36' 17.6" 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, arXiv:0812.3662). This circular was automatically generated, and is an official product of the Swift-XRT team.
GCN 9773 table
GRB_name GRB090812A
GCN_number 9773
Detection_method GROND
redshift 2.4500
Circular_text TITLE: GCN CIRCULAR NUMBER: 9773 SUBJECT: GRB 090812: GROND Observations of the Optical/NIR Afterglow DATE: 09/08/12 11:54:31 GMT FROM: Thomas Kruehler at MPE/MPI Adria Updike (Clemson University), Arne Rau, Thomas Kruehler, Felipe Olivares, and Jochen Greiner (all MPE Garching) report on behalf of the GROND team: We observed the field of GRB 090812 (Swift trigger 359711; Stamatikos et al., GCN #9768) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m ESO/MPI telescope at La Silla Observatory (Chile). Due to cloud coverage, observations started only at 08:13 UT on August 12, 2 hours and 11 minutes after the GRB trigger. They were performed at an average seeing of 1.1" and at an average airmass of 1.2 with light cirrus, and continued until twilight. We clearly detect the afterglow in stacked images (Stamatikos et al. GCN #9768, Cenko GCN #9769). Based on the first 4 min of total exposures, we estimate preliminary magnitudes and upper limits (all in AB system) of g' = 22.15 +- 0.15 mag, r' = 21.50 +- 0.08 mag, i' = 21.30 +- 0.13 mag, z' = 21.02 +- 0.12 mag, J = 20.57 +- 0.15 mag, H > 19.8 mag, K > 18.9 mag The given magnitudes are calibrated against SDSS as well as 2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.02 mag in the direction of the burst (Schlegel et al. 1998). The foreground extinction corrected spectral energy distribution is well fit with a pure power law and a spectral index of beta = 1.1+/-0.2 and no strong evidence of excess extinction. The flux difference between the g' band magnitude and the extrapolation of the power law as defined by r'i'z'J is consistent with Lyman-alpha absorption at a redshift of 2.45 as reported by de Ugarte Postigo et al. (GCN #9771).
GCN 9774 table
GRB_name GRB090812A
GCN_number 9774
Detection_method Swift-UVOT Det
redshift 2.4520
Circular_text TITLE: GCN CIRCULAR NUMBER: 9774 SUBJECT: GRB090812: Swift/UVOT observations DATE: 09/08/12 13:52:31 GMT FROM: Patricia Schady at MSSL/Swift P. Schady (MSSL-UCL) and M. Stamatikos (NASA/ORAU) report on behalf of the Swift UVOT team: The Swift/UVOT began settled observations of the field of GRB 090812 86s after the BAT trigger (Stamatikos et al., GCN Circ. 9768). An uncatalogued, fading source is detected in the UVOT white, v, b and u band filters at the position reported in Stamatikos et al. (GCN Circ. 9768), consistent with the refined XRT error circle (Goad et al., GCN Circ. 9772). The detection of the afterglow in the white, v, b and u filters is consistent with the spectroscopic redshift of z=2.452 reported by Ugarte Postigo et al. (GCN Circ. 9771). Early time UVOT obserations indicate a decay rate of alpha~1.5. The magnitudes and 3-sigma upper limits for the UVOT observations of GRB 090812 in each filter are as follows: Filter T_start(s) T_stop(s) Exp(s) Mag/3-sig UL white 86 235 146 17.35+/-0.03 v 628 647 19 18.17+/-0.41 b 554 573 19 18.62+/-0.28 u 299 548 246 18.65+/-0.11 uvw1 677 1124 58 > 19.20 uvm2 652 1099 58 > 18.72 uvw2 603 1050 58 > 19.13 The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel et al. 1998). The photometry is on the UVOT photometric system described in Poole et al. (2008, MNRAS, 383, 627).
GCN 9775 table
GRB_name GRB090812A
GCN_number 9775
Detection_method Swift-BAT Det
ra 353.2000°
decl -10.6090°
Circular_text TITLE: GCN CIRCULAR NUMBER: 9775 SUBJECT: GRB 090812 Swift-BAT Refined Analysis DATE: 09/08/12 15:09:27 GMT FROM: Michael Stamatikos at OSU/GSFC W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), 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), M. Stamatikos (OSU/NASA/GSFC), J. Tueller (GSFC), T. N. Ukwatta (GWU) on behalf of the Swift-BAT team: Using the data set from T-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 090812 (trigger #359711) (Stamatikos, et al., GCN Circ. 9768). The BAT ground-calculated position is RA, Dec = 353.200, -10.609 deg which is RA(J2000) = 23h 32m 47.9s Dec(J2000) = -10d 36' 34.1" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 78%. The burst starts at ~T-4 sec and ends at ~T+120 sec, with 3 peaks at ~T+5 sec, ~T+27 sec and ~T+55 sec, respectively. T90 (15-350 keV) is 66.7 +- 14.7 sec (estimated error including systematics). The time-averaged spectrum from T-5.4 to T+113.9 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.24 +- 0.05. The fluence in the 15-150 keV band is 5.8 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+26.82 sec in the 15-150 keV band is 3.6 +- 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/359711/BA/. [GCN OPS NOTE(13aug09): Per author's request, the "080912" was changed to "090812" in the Subject line.]
GCN 9776 table
GRB_name GRB090812A
GCN_number 9776
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 9776 SUBJECT: GRB 090812, RIMOTS optical upper limits DATE: 09/08/12 15:14:43 GMT FROM: Kazuhiro Noda at Miyazaki U K.Noda, A.Daikyuji, K.Kono, E.Sonoda, N.Ohmori, H.hayasi, M.Yamauchi (University of Miyazaki) We have observed the field covering the error circle of GRB 090812 (Swift trigger 359711, GCN 9768, M. Stamatikos et al.) with the unfiltered CCD camera on the 30-cm telescope at University of Miyazaki. The observation was started 12:30:59 UT, about 6.5 hr after the Swift trigger time. We have compared our data of 30 sec exposures with the USNO-A2.0 catalog, There is no new source at the reported position. ((GCN 9768(M. Stamatikos et al.), GCN 9769(S. B. Cenko et al.) GCN 9770(R.J. Smith et al.), GCN 9772(M.R. Goad et al.) GCN 9773(Adria Updike et al.), GCN 9774(P. Schady et al.)) the upper limits are as follows: -------------------------------------------------------------- Start(UT) End(UT) Num. of frames Limit (mag.) -------------------------------------------------------------- 12:30:59 12:31:29 1 12.1 12:30:59 13:45:22 62 17.3 ---------------------------------------------------------------
GCN 9777 table
GRB_name GRB090812A
GCN_number 9777
Detection_method Swift Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 9777 SUBJECT: GRB 090812: Swift XRT refined analysis DATE: 09/08/12 15:19:27 GMT FROM: Rhaana Starling at U of Leicester R. Starling (U. Leicester) and M. Stamatikos (NASA/ORAU) report on behalf of the Swift-XRT team: We have analysed the first two orbits of Swift XRT data for GRB 090812 (trigger=359711, Stamatikos et al. GCN Circ. 9768) spanning T0+78 s to T0+12.4 ks. The UVOT-enhanced XRT position was given by Goad et al. in GCN Circ. 9748. The light curve shows initial flaring, with two large flares overlaid on a power law of decay slope alpha1=1.5+/-0.5. The power law then breaks at approximately 960 s to a shallower slope of alpha=1.05+/-0.10. A power law is an acceptable fit to a spectrum formed from the first orbit windowed timing (WT) mode data centred at T0+230 s, with a photon index, Gamma, of 1.97+/-0.03. The resulting column density at the source (z=2.452, de Ugarte Postigo et al. GCN Circ. 9771) is (1.00+/-0.09)e22 cm^-2 in addition to the Galactic column of 2.26e20 cm^-2 (Kalberla et al. 2005). The 0.3-10 keV observed (unabsorbed) count to flux conversion is 1 ct = 3.4e-11 (4.2e-11) erg/cm2/s. A fit to the spectrum formed from the first and second orbit photon counting (PC) mode data centred at T0+2760 s is consistent with the WT spectral results. Interestingly, the X-ray spectral slope we derive is consistent with slope reported for the optical data from GROND, centred at T0+7860 s (Updike et al. GCN Circ. 9773.), which may imply a single spectral slope between the X-ray and optical bands several thousand seconds after the trigger. While we only have two orbits of data, if we assume the light curve continues to decay with a power law of index alpha=1.05, the predicted count rate at T+24 hours will be 0.023 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 7.7e-13 (9.5e-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00359711. This circular is an official product of the Swift-XRT team.
GCN 9778 table
GRB_name GRB090812A
GCN_number 9778
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 9778 SUBJECT: GRB 090812: RAPTOR detections during the burst DATE: 09/08/12 17:15:03 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 359711 (Stamatikos et al., GCN 9768) under good observing conditions. Our narrow-field instruments began observing the location at 06:02:32.9 UTC, 24.0 s after the Swift trigger (7.0 s after receipt of GCN message). We obtained simultaneous observations during the gamma-ray emitting interval in Cousins V, R, and I bands as well as unfiltered data. We detect the optical counterpart in all color bands. Initial analysis of our unfiltered data calibrated to the USNO-B1 R-band revals the counterpart brightening until ~T=70s after the trigger and then beginning a steady decline. The following table gives selected observations, not corrected for extinction, from this event. Further analysis of the multi-color data is underway. t-mid(s) exp(s) mag mag-err -------------------------------------------- 26.48 5.0 15.98 0.18 46.08 5.0 15.39 0.11 73.55 5.0 14.84 0.07 91.71 5.0 15.13 0.09 101.21 5.0 15.25 0.10 141.62 10.0 15.63 0.10
GCN 9779 table
GRB_name GRB090812A
GCN_number 9779
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 9779 SUBJECT: GRB 090812: Faulkes Telescope South Continued Optical Monitoring DATE: 09/08/12 18:02:44 GMT FROM: Zach Cano at ARI/John Moores Liverpool Z. Cano (Liverpool JMU), C. Guidorzi (U. Ferrara), C. Mundell, R.J. Smith, D. Bersier, A. Melandri, I.A. Steele, S. Kobayashi, C.J. Mottram, (Liverpool JMU), A. Gomboc (U. Ljubljana) report, on behalf of a large collaboration: Following our report of observations on the Liverpool Telescope (Smith et al. GCN 9520) we continued monitoring the field of GRB090812 (Swift trigger 359711, Stamatikos et al. GCN 9768) on the Faulkes Telescope South (Australia) from 5.88 hours to 8.40 hours post burst in r' and i' bands. We find from 6 x 300s stacked images: t_exp filter t-T0 R-mag ---------------------------------------------------------- 30min i' 5.88 hours 22.43 +/- 0.25 30min i' 8.40 hours 22.85 +/- 0.25 30min r' 6.60 hours 22.31 +/- 0.09 ---------------------------------------------------------- The calibration is still preliminary and determined against stars in the sdss field. Finally, we find the decay rate in i' from 111s to 2.35ks post burst is consistent with alpha ~ 1.25 +/- 0.1
GCN 9780 table
GRB_name GRB090812A
GCN_number 9780
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 9780 SUBJECT: GRB 090812: WIRO NIR upper limit DATE: 09/08/12 20:06:03 GMT FROM: Jay Norris at U. of Denver Alexander Kutyrev (CRESST/UMCP/GSFC), Jay Norris (U. Denver), report on behalf of the Goddard/U. Wyoming NIR camera collaboration. We observed the afterglow position of GRB 090812 as reported by Cenko (GCN Circ. 9769) with the 2.3-meter WIRO telescope and the Goddard NIR camera, commencing 10:28 UT, 4.4 hrs after the Swift trigger (Stamatikos et al., GCN Circ. 9768). Using stacked J-band images with a total exposure time of 1360 s, via comparison with two adjacent 2-MASS stars, we derive the following 3 sigma upper limit for the afterglow: Tmid (UT) Mag 10:46 J-band > 21.2
GCN 9814 table
GRB_name GRB090812A
GCN_number 9814
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 9814 SUBJECT: VLA radio non-detection of GRB 090812 DATE: 09/08/16 02:03:58 GMT FROM: Poonam Chandra at U Virginia/NRAO Poonam Chandra (RMC) and Dale A. Frail (NRAO) report on behalf of a larger collaboration: "We used the Very Large Array to observe the field of view toward GRB 090812 (GCN 9768) at a frequency of 8.46 GHz at two epochs, on 2009 Aug. 13.37 UT and Aug. 15.41 UT. The GRB radio afterglow is undetected in both the observations. The peak fluxes at the P60 optical afterglow position (GCN 9769) in the two observations are 104+/-43 uJy and 63+/-62 uJy, respectively. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc."
GCN 9816 table
GRB_name GRB090812A
GCN_number 9816
Detection_method Suzaku WAM Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 9816 SUBJECT: GRB 090812: Suzaku WAM observation of the prompt emission DATE: 09/08/17 09:36:54 GMT FROM: Kazuhiro Noda at Miyazaki U K. Noda, E. Sonoda, N. Ohmori, K. Kono, H. Hayashi, A. Daikyuji, Y. Nishioka, M. Yamauchi (Univ. of Miyazaki), 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), K. Yamaoka, S. Sugita (Aoyama Gakuin U.), Y. E. Nakagawa, T. Tamagawa (RIKEN), S. Hong (Nihon U.), N. Vasquez (Tokyo Tech.), on behalf of the Suzaku WAM team, report: The long GRB 090812 (Swift/BAT trigger #359711; Stamatikos et al., GCN 9768; Baumgartner et al., GCN 9775) triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 2009-08-12 06:02:33.68 UT (=T0). The observed light curve shows a double-peaked structure, starting at T0-30 s and ending at T0+40 s, with a total duration (T90) of about 36 s. The fluence in 100 - 1000 keV was 1.50(-0.46, +0.40) x10-6 erg/cm2. The 1-s peak flux measured from T0+2 s was 2.77(-0.35, +0.23) photons/cm2/s in the same energy range. Preliminary result shows that the time-averaged spectrum from T0-30 s to T0+40s is well fitted by a power-law with exponential cutoff model: dN/dE ~ E^{-alpha} * exp(-(2-alpha)*E/Epeak) with alpha: 1.31(-1.09, +0.81), and Epeak: 340(-138, +254) keV (chi2/d.o.f. = 36.6/37). 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/trig/grb_table.html
GCN 9821 table
GRB_name GRB090812A
GCN_number 9821
Detection_method Konus-Wind Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 9821 SUBJECT: GRB 090812: Konus-Wind and Swift/BAT joint spectral analysis DATE: 09/08/17 15:28:46 GMT FROM: Valentin Pal'shin at Ioffe Inst V. Pal'shin, S. Golenetskii, R.Aptekar, E. Mazets, D. Frederiks, and T. Cline on behalf of the Konus-Wind team, T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), and T. Ukwatta (GWU) report: The most intense pulse of the long GRB 090812 (Swift/BAT trigger #359711: Stamatikos et al., GCN Circ. 9768, Baumgartner et al. GCN Circ. 9775) triggered Konus-Wind at T0(KW)=21758.942 s UT (06:02:38.942). Since the Konus-Wind trigger record misses the early weaker part of this GRB, we have only Konus-Wind 3-channel spectral data for the whole burst which cover the energy range from 23 keV to 1.4 MeV. We performed the Konus-Wind and Swift/BAT joint spectral analysis of this GRB to derive the broad-band spectral and energetic parameters of this burst. The time interval of the spectral data is chosen from T0(BAT)-6.7 to T0(BAT)+58.1 sec where T0(BAT) is the trigger time of BAT at 06:02:08.897 UTC. The energy ranges which we used in the joint spectral analysis are 23-1400 keV and 15-150 keV for the Konus-Wind and the Swift/BAT respectively. The spectral data of two instruments are fitted with the spectral model multiplied by the constant factor to take into account the systematic effective area uncertainties in the response matrices of each instrument. The spectrum is well fitted with a power-law with exponential cutoff model: dN/dE ~ E^{alpha}*exp(-(2+alpha)*E/Epeak). The constant factors of each instrument agree within 15%. No systematic residual from the best fit model is seen in the spectral data of each instrument. The best fit spectral parameters are: alpha = -1.03(-0.06, +0.07) and Epeak = 586(-152, +243) keV (chi2/dof = 59.3/57). The best fit spectral parameters for the GRB (Band) model fixing beta = -2.5 are: alpha = -1.03 +/- 0.07, and Epeak = 572(-159, +251) keV (chi2/dof = 59.6/57). The energy fluence in the 15-1400 keV band calculated by a power-law with exponential cutoff model for this 64.8 sec interval is (2.61 +/- 0.34)x10^-5 erg/cm2 (assuming the constant factor of the Konus-Wind is fixed to 1). Assuming z = 2.452 (de Ugarte Postigo et al. GCN Circ. 9771) and a standard cosmology model with H_0 = 71 km/s/Mpc, Omega_M = 0.27, Omega_Lambda = 0.73, the isotropic energy release is E_iso = 4.4 (-0.6, +0.7)x10^53 erg in 1 keV to 10 MeV at the GRB rest frame extrapolating the best Band function fit fixing beta = -2.5, and the rest frame peak energy is Epeak_rest = 2.0(-0.5, +0.9) MeV. 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/GRB090812_T21758/
GCN 9999 table
GRB_name GRB090812A
GCN_number 9999
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 9999 SUBJECT: GRB 090812: Skynet/PROMPT and GORT Observations DATE: 09/10/08 04:54:57 GMT FROM: Josh Haislip at U.North Carolina J. Haislip, D. Reichart, K. Ivarsen, L. Cominsky, K. McLin, T. Graves, G. Spear, 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 090812 (Stamatikos et al., GCN 9768) with four of the 16" PROMPT telescopes at CTIO beginning 3.9 minutes after the trigger in UBVRI through variable cloud cover. Skynet continued observing with the 14" GORT telescope at Hume Observatory in California beginning 48.4 minutes after the the trigger in RI. We detect the afterglow (Stamatikos et al., GCN 9768). Stacking only images that increase the limiting magnitude yields: mean 1-sig. 1-sig. time sys. stat. since cal. cal. cal. trig. tel. exp. fil. magnitude stars* unc. unc. (# x s) (mag) (mag) 15.0 m PROMPT-4 2 x 80 R > 17.7 (3 sig.) 50 SDSS 7 0.008 0.010 15.0 m PROMPT-5 2 x 80 I > 17.0 (3 sig.) 20 SDSS 7 0.026 0.010 15.0 m PROMPT-2 2 x 80 V > 17.4 (3 sig.) 15 SDSS 7 0.030 0.020 32.1 m PROMPT-3 2 x 80 B > 18.5 (3 sig.) 25 SDSS 7 0.028 0.031 32.6 m PROMPT-2 4 x 80 V > 18.3 (3 sig.) 15 SDSS 7 0.039 0.010 + 1 x 40 32.7 m PROMPT-4 5 x 80 R > 18.4 (3 sig.) 50 SDSS 7 0.008 0.005 32.7 m PROMPT-5 5 x 80 I > 17.8 (3 sig.) 20 SDSS 7 0.026 0.005 62.0 m GORT 6 x 80 R > 18.8 (3 sig.) 34 SDSS 7 0.039 0.003 76.8 m GORT 9 x 80 I > 18.7 (3 sig.) 43 SDSS 7 0.097 0.003 117.3 m PROMPT-2 8 x 80 V > 18.7 (3 sig.) 17 SDSS 7 0.019 0.006 119.1 m PROMPT-4 11 x 80 R > 19.1 (3 sig.) 62 SDSS 7 0.229 0.003 119.2 m PROMPT-5 11 x 80 I > 18.4 (3 sig.) 25 SDSS 7 0.117 0.003 120.0 m PROMPT-3 10 x 80 B > 19.4 (3 sig.) 26 SDSS 7 0.085 0.011 3.2 h PROMPT-3 24 x 80 B > 21.3 (3 sig.) 26 SDSS 7 0.085 0.003 3.2 h GORT 16 x 80 I > 19.2 (3 sig.) 43 SDSS 7 0.097 0.002 3.4 h GORT 20 x 80 R > 20.0 (3 sig.) 34 SDSS 7 0.039 0.001 3.5 h PROMPT-2 67 x 80 V 21.05 +0.35 -0.27 17 SDSS 7 0.019 0.001 3.5 h PROMPT-5 66 x 80 I 20.60 +0.26 -0.21 25 SDSS 7 0.117 0.001 3.5 h PROMPT-4 65 x 80 R 21.35 +0.28 -0.22 62 SDSS 7 0.229 0.001 3.6 h PROMPT-3 37 x 80 U > 19.5 (3 sig.) 30 SDSS 7 0.015 0.012 * Transformed using Jester et al., 2005, ApJ, 130, 873.