//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13716 SUBJECT: GRB 120907A: Swift detection of a burst with optical counterpart DATE: 12/09/07 00:38:43 GMT FROM: Scott Barthelmy at NASA/GSFC J. L. Racusin (NASA/GSFC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), S. T. Holland (STScI), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), T. Sakamoto (NASA/UMBC), B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 00:24:23 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 120907A (trigger=532871). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 74.741, -9.314 which is RA(J2000) = 04h 58m 58s Dec(J2000) = -09d 18' 48" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single pulse with a duration of about 5 sec. The peak count rate was ~2000 counts/sec (15-350 keV), at ~2 sec after the trigger. The XRT began observing the field at 00:25:45.1 UT, 82.0 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 74.7494, -9.3143 which is equivalent to: RA(J2000) = 04h 58m 59.86s Dec(J2000) = -09d 18' 51.3" with an uncertainty of 2.1 arcseconds (radius, 90% containment). This location is 29 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 5.35 x 10^20 cm^-2 (Kalberla et al. 2005). UVOT took a finding chart exposure of 250 seconds with the U filter starting 142 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 04:59:00.01 = 74.75005 DEC(J2000) = -09:18:54.2 = -9.31505 with a 90%-confidence error radius of about 0.63 arc sec. This position is 4.6 arc sec. from the center of the XRT error circle. The estimated magnitude is 17.63 with a 1-sigma error of about 0.15. No correction has been made for the expected extinction corresponding to E(B-V) of 0.09. Burst Advocate for this burst is J. L. Racusin (judith.racusin AT 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.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13717 SUBJECT: GRB 120907A: ROTSE-III Optical Limits DATE: 12/09/07 00:59:19 GMT FROM: Weikang Zheng at U.of Michigan W. Zheng (U Mich), H. Flewelling (IfA/Hawaii), report on behalf of the ROTSE collaboration: ROTSE-IIId, located at the Turkish National Observatory at Bakirlitepe, Turkey, automatically responded to GRB 120907A (Swift trigger 532871; Racusin et al., GCN 13716). An automated response took the first image at 00:31:23.7 UT, 420 s after the burst, under fair conditions. We took 10 5-sec, 10 20-sec and 0 60-sec exposures. These unfiltered images are calibrated relative to USNO A2.0 (R). Imaging is on going. We do not detect the candidate afterglow reported in GCN 13716. Individual images have limiting magnitudes ranging from 14.0-15.4; we set the following specific limits. start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd? -------------------------------------------------------------------- 00:31:23.7 00:31:07.0 5 14.8 420 N 00:31:23.7 00:33:35.0 50 15.8 420 Y 00:33:40.0 00:38:20.0 200 16.4 557 Y //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13718 SUBJECT: GRB 120907A MASTER optical observations DATE: 12/09/07 02:35:27 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, A.Belinski, N.Tyurina, N.Shatskiy, P.Balanutsa, D.Zimnukhov, A.Kuznetsov, V.V.Chazov, A.Kuznetsov, A.Sankovich Moscow Lomonosov State University, Sternberg Astronomical Institute, K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Krushinski, I.Zalozhnich, A. Popov, A. Bourdanov, A. Punanova Ural Federal University Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Kislovodsk was pointed to the GRB120907A 375 s after notice time and 389 sec after GRB time at 2012-09-07 00:30:52 UT in a two polarizations. We are marginaly see SWIFT-UVOT optical transient (J. L. Racusin et. al. GCN 13716) on out first images. The unfiltred OT magnitude is about 17.5 mag. The long pointing time was due to some technical issues. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13719 SUBJECT: GRB 120907A: NOT optical observations DATE: 12/09/07 06:51:15 GMT FROM: Thomas Kruehler at Dark Cosmology Center T. Kruehler (DARK/NBI), D. Xu (WIS) and S. Schulze (PUC and MCSS) report on behalf of a larger collaboration: We observed the field of the Swift GRB 120907A (Racusin et al., GCN 13716) with the NOT telescope equipped with StanCam. Eight I-band images with integration times of 120 s each were obtained on 2012-09-07 starting at 03:49 UT, which is roughly 3.4 hours after the trigger. The optical afterglow (Racusin et al., GCN 13716) is clearly detected in our images. We derive a preliminary magnitude of I = 20.2 +/- 0.1 centered at approximatly 3.6 hours after the trigger and assuming that the USNO star at RA(J2000) = 04:58:58.52, decl.(J2000) = -09:18:00.7 has an I-band magnitude of 15.28. An additional systematic uncertainty in the absolute brightness of about 0.3 mag is expected due to the calibration against the USNO catalog. We are grateful to the NOT staff and observer, Anlaug Amanda Djupvik, for obtaining these observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13720 SUBJECT: GRB 120907A: Swift-BAT refined analysis DATE: 12/09/07 14:46:18 GMT FROM: Scott Barthelmy at NASA/GSFC M. Stamatikos (OSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), J. L. Racusin (NASA/GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-61 to T+242 sec from recent telemetry downlinks, we report further analysis of BAT GRB 120907A (trigger #532871) (Racusin, et al., GCN Circ. 13714). The BAT ground-calculated position is RA, Dec = 74.736, -9.323 deg which is RA(J2000) = 04h 58m 56.7s Dec(J2000) = -09d 19' 21.2" with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 21%. The mask-weighted light curve shows 2 or 3 somewhat overlapping peaks starting at ~T-1 sec, peaking at ~T+1 sec, and ending at ~T+20 sec. T90 (15-350 keV) is 16.9 +- 8.9 sec (estimated error including systematics). The time-averaged spectrum from T-0.04 to T+18.76 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.73 +- 0.25. The fluence in the 15-150 keV band is 6.7 +- 1.1 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.10 sec in the 15-150 keV band is 2.9 +- 0.4 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/532871/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13721 SUBJECT: GRB 120907A: Fermi GBM detection DATE: 12/09/07 15:27:07 GMT FROM: George A. Younes at USRA/NASA/MSFC George Younes (MSFC/USRA) reports on behalf of the Fermi GBM Team: "At 00:24:24.51 UT on 07 September 2012, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 120907A (trigger 368670267 / 120907017) which was also detected by the Swift/BAT (Barthelmy et al. 2012, GCN 13716). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight is 110 degrees. The GBM light curve consists of a single pulse with a duration (T90) of about 5.8 s (50-300 keV). The time-averaged spectrum from T0-1.4 s to T0+0.7 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.75 +/- 0.25 and the cutoff energy, parameterized as Epeak, is 154.50 +/- 32.90 keV. The event fluence (10-1000 keV) in this time interval is (7.8 +/- 1.1)E-07 ergs/cm^2. The 1-sec peak photon flux measured starting from T0-1.1 s in the 10-1000 keV band is 4.3 +/- 0.4 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13722 SUBJECT: GRB 120907A: Enhanced Swift-XRT position DATE: 12/09/07 16:07:31 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 4509 s of XRT Photon Counting mode data and 5 UVOT images for GRB 120907A, 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 = 74.74990, -9.31501 which is equivalent to: RA (J2000): 04h 58m 59.98s Dec (J2000): -09d 18' 54.0" with an uncertainty of 1.6 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). This circular was automatically generated, and is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13723 SUBJECT: GRB 120907A: Spectroscopy from OSIRIS/GTC DATE: 12/09/07 16:35:20 GMT FROM: Antonio de Ugarte Postigo at IAA-CSIC R. Sanchez-Ramirez, J. Gorosabel (IAA-CSIC), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI) and J.M. Gonzalez Perez (GTC) report on behalf of a larger collaboration: We have obtained spectroscopy of the afterglow of GRB 120907A (Racusin et al. GCN 13716) with OSIRIS/ GTC (La Palma, Spain) on Sep 7.20647-7.23893 UT (4.55-5.33 hours post GRB). The observation consisted of 3x900s exposures using the R1000R grating, covering the range from 5100 to 10000 A with a resolution of ~1100. In the combined spectrum we detect several absorption features corresponding to FeII, MgII, MgI and CaII at a common redshift of z=0.970, which we identify as the redshift of the GRB. We acknowledge the excellent support of the GTC staff. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13724 SUBJECT: GRB 120907A: Swift-XRT refined Analysis DATE: 12/09/07 16:38:07 GMT FROM: Phil Evans at U of Leicester A. Maselli (INAF-IASFPA), V. Mangano (INAF-IASFPA), A. Melandri (INAF-OAB), J.A. Kennea (PSU), M.C. Stroh (PSU), D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Pagani (U. Leicester) and J.L. Racusin report on behalf of the Swift-XRT team: We have analysed 16 ks of XRT data for GRB 120907A (Racusin et al. GCN Circ. 13716), from 93 s to 46.4 ks after the BAT trigger. The data comprise 76 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Goad et al. (GCN. Circ 13722). The late-time light curve (from T0+4.5 ks) can be modelled with a power-law decay with a decay index of alpha=1.02 (+/-0.08). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.91 (+0.13, -0.12). The best-fitting absorption column is 10.0 (+3.1, -2.9) x 10^20 cm^-2, in excess of the Galactic value of 5.4 x 10^20 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.8 x 10^-11 (4.7 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 10.0 (+3.1, -2.9) x 10^20 cm^-2 Galactic foreground: 5.4 x 10^20 cm^-2 Excess significance: 2.7 sigma Photon index: 1.91 (+0.13, -0.12) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00532871. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13725 SUBJECT: GRB 120907A: Swift/UVOT Detection DATE: 12/09/07 19:17:57 GMT FROM: Samantha Oates at MSSL S. R. Oates (MSSL-UCL) and J. L. Racusin (NASA/GSFC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 120907A 142 s after the BAT trigger (Racusin et al., GCN Circ. 13716). A source consistent with the enhanced XRT position (Goad et al. GCN Circ. 13722) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 04:59:00.00 = 74.75002 (deg.) Dec (J2000) = -09:18:54.0 = -9.31501 (deg.) with an estimated uncertainty of 0.52 arc sec. (radius, 90% confidence). Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag v 449 6811 471 >19.5 b 398 567 39 19.02 +/- 0.29 u 142 392 246 17.67 +/- 0.08 w1 498 666 40 18.27 +/- 0.32 m2 473 1122 79 18.68 +/- 0.36 w2 424 642 39 18.56 +/- 0.37 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.09 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13726 SUBJECT: GRB 120907A: EVLA observations DATE: 12/09/08 16:47:19 GMT FROM: Tanmoy Laskar at Harvard U T. Laskar, A. Zauderer and E. Berger (Harvard) report: "We observed the position of GRB 120907A (GCN 13716) with the EVLA beginning 2012 September 7.46 UT (10.5 hours after the burst). No significant radio emission is detected at the enhanced Swift-XRT position (GCN 13724), the UVOT position (GCN 13725) or optical position (GCN 13719). Preliminary analysis indicates a three-sigma upper limit of 75 uJy at 5.8 GHz. Further observations are planned." -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 3rd Yr Graduate Student in Astronomy Harvard-Smithsonian Center for Astrophysics A-107, 60 Garden St, Cambridge (617)-495-5989 http://www.cfa.harvard.edu/~tlaskar Mobile: (617)-899-9361 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13743 SUBJECT: GRB 120907A: SMA upper limits DATE: 12/09/11 02:18:39 GMT FROM: Ashley Zauderer at CfA G. Petitpas (SAO), A. Zauderer, T. Laskar, E. Berger (Harvard) report on behalf of the SMA Rapid Transients (SMART) Key Project: "We observed the position of GRB 120907A (Racusin et al; GCN 13716) with the Submillimeter Array (SMA) beginning 2012 Sep 7.63 UT (dt ~ 0.6 d). At a mean frequency of 230 GHz, we do not detect significant radio emission within the enhanced Swift/XRT error circle (Goad et al; GCN 13702) to a 3-sigma upper limit of 2.7 mJy. Beginning 2012 Sep 8.5 UT (dt ~ 1.5 d), we repeated our observations, and report a 3-sigma upper limit of 2.4 mJy. We thank the SMA Observatory staff for its support." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13761 SUBJECT: GRB 120907A: optical observations of ISON-Kislovodsk DATE: 12/09/13 18:53:47 GMT FROM: Alexei Pozanenko at IKI, Moscow V. Nevski (ISON-Kislovodsk Observatory), A. Volnova (SAI MSU/IKI), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger collaboration: We observed the field of GRB 120907A (Racusin et al., GCN 13716) with Santel-400AN (0.4-m f/3) telescope Ïf ISON-Kislovodsk observatory starting on Sep. 07 (UT) 00:34:32, i.e. ~10.2 minutes after burst trigger. We took several unfiltered images of 30 s and 60 s exposures. In a stacked images we clearly detect optical afterglow of GRB 120907A (Racusin et al., GCN 13716; Gorbovskoy et al., GCN 13718; Kruehler et al., GCN 13719). A preliminary photometry of stacked frames is based on the USNO-B1.0 (R2) nearby stars: T_start, T0+, Exp, Filter, OT (UT) mid (d) (s) 00:34:32 0.00899 10x30 none 18.55+/-0.09 00:51:45 0.02120 5x60 none 18.95+/-0.13 00:58:09 0.02980 8x60 none 19.52+/-0.20 01:16:32 0.04339 8x60 none 19.50+/-0.20