//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13727 SUBJECT: GRB 120909A: Swift detection of a burst DATE: 12/09/09 01:54:56 GMT FROM: David Palmer at LANL S. Immler (CRESST/GSFC/UMD), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), S. T. Holland (STScI), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 01:42:03 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 120909A (trigger=533060). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 275.685, -59.426 which is RA(J2000) = 18h 22m 44s Dec(J2000) = -59d 25' 34" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows one, possibly two, peaks with a duration of about 5 sec. The peak count rate was ~2000 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began observing the field at 01:43:36.6 UT, 93.4 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 275.7388, -59.4485 which is equivalent to: RA(J2000) = +18h 22m 57.31s Dec(J2000) = -59d 26' 54.6" with an uncertainty of 4.8 arcseconds (radius, 90% containment). This location is 127 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 7.55e-09 erg cm^-2 s^-1 (0.2-10 keV). Because of an earth limb constraint, Swift slewed away before UVOT could take its initial exposures. Subsequent orbits will include UVOT observations. Burst Advocate for this burst is S. Immler (stefan.immler 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: 13728 SUBJECT: Skynet/PROMPT Observations of GRB120909A DATE: 12/09/09 02:24:04 GMT FROM: Aaron LaCluyze at U.North Carolina J. Haislip, A. LaCluyze, K. Ivarsen, D. Reichart, J. Moore, H. T. Cromartie, R. Egger, A. Foster, N. Frank, M. Nysewander, A. Oza, E. Speckhard, A.Trotter, and J. A. Crain report: Skynet observed the field of GRB120909A (GCN 13727, Swift trigger #533060) with the PROMPT telescopes located at CTIO in Chile beginning ~4 minutes after the burst. We detect a fading, uncataloged source at RA 18:22:56.72 DEC -59:26:54.0, roughly coinciding with the location of the Swift trigger with an initial magnitude of ~16.3 in R, calibrated to the NOMAD catalog. Further observations are ongoing. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13729 SUBJECT: GRB 120909A: GROND detection of the afterglow DATE: 12/09/09 02:41:37 GMT FROM: Vladimir Sudilovsky at MPE V. Sudilovsky (MPE Garching), S. Schmidl (TLS Tautenburg), D.A. Kann (MPE Garching) and J. Greiner (MPE Garching) report on behalf of the GROND team: We observed the field of GRB 120909A (Swift trigger 533060; Immler et al., GCN #13727) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG/ESO telescope at La Silla Observatory (Chile). Observations started at 01:44 UT, September 09, 140s after the burst, and are continuing. They were performed at an average seeing of 1".6 and at an average airmass of 1.2 . We found a single point source within the 4".8 Swift-XRT error circle reported by Immler et al. (GCN #13727) at RA (J2000.0) = 18h 22m 56.72s DEC (J2000.0) = -59d 26' 54".1 with an uncertainty of 0".5 in each coordinate, which is consistent with the position reported by Haislip et al. (GCN #13728) . Based on the first 141s of total exposures in g'r'i'z' and 240s in JHK, we estimate preliminary magnitudes (all in AB) of g' = 18.4 +- 0.1, r' = 16.6 +- 0.1, i' = 15.8 +- 0.1, z' = 15.5 +- 0.1, J = 14.8 +- 0.1, H = 14.5 +- 0.1, and K = 14.3 +- 0.1. Based on the the significantly lower flux in g', this suggests a redshift z>3. Given magnitudes are calibrated against GROND zeropoints as well as 2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.08 mag in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13730 SUBJECT: GRB 120909A: X-Shooter redshift 3.93 DATE: 12/09/09 05:22:52 GMT FROM: Olga Hartoog at U of Amsterdam O. E. Hartoog (Uva, NL), D. Malesani (DARK/NBI), K. Wiersema (U. Leicester, UK), T. Kruehler (DARK/NBI), S. Schulze (PUC and MCSS), A. de Ugarte Postigo (IAA/CSIC and DARK/NBI), V. D'Elia (INAF/Roma and ASI/ASDC), J. P. U. Fynbo (DARK/NBI), report on behalf of the X-shooter GRB GTO collaboration: We observed the optical counterpart of GRB 120909A (Immler et al., GCN 13727; Haislip et al., GCN 13728; Sudilovsky et al., GCN 13729) with the ESO VLT equipped with the X-shooter spectrograph. Observations were carried out starting on 2012 Sep 9.14 UT (1.7 hr after the GRB), for a total exposure time of 20 min, covering the wavelength range 3000-25000 AA. We detect several absorption features, including Ly-a, FeII, NiII, SiII, SII, AlII, AlIII, CII, OI, CIV, ZnII all at a common redshift z = 3.93. In particular, the presence of fine-structure lines (Fe II*, SiII*, OI*, OI**, CII*) makes the redshift securely associated to the GRB. We acknowledge support from the VLT staff, in particular Giovanni Carraro and Giacomo Beccari. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13732 SUBJECT: GRB 120909A: Enhanced Swift-XRT position DATE: 12/09/09 13:23:25 GMT FROM: Phil Evans at U of Leicester J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team. Using 1720 s of XRT Photon Counting mode data and 5 UVOT images for GRB 120909A, 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 = 275.73656, -59.44863 which is equivalent to: RA (J2000): 18h 22m 56.78s Dec (J2000): -59d 26' 55.1" with an uncertainty of 1.4 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: 13733 SUBJECT: GRB 120909A: Swift-BAT refined analysis DATE: 12/09/09 15:03:07 GMT FROM: Scott Barthelmy at NASA/GSFC T. N. Ukwatta (MSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), S. Immler (CRESST/GSFC/UMD), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC) (i.e. the Swift-BAT team): Using the data set from T-41 to T+556 sec from recent telemetry downlinks, we report further analysis of BAT GRB 120909A (trigger #533060) (Immler, et al., GCN Circ. 13727). The BAT ground-calculated position is RA, Dec = 275.735, -59.432 deg which is RA(J2000) = 18h 22m 56.5s Dec(J2000) = -59d 25' 55.2" with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 48%. The mask-weighted light curve shows multiple overlapping peaks. The burst was already occurring when Swift-BAT came out of the SAA at ~T-40 sec. The observed peaks occurred at ~T-38, ~T+1, ~T+28, and ~T+48 sec. The burst returned to baseline at ~T+200 sec. There is a possible peak at ~T+490 to ~T+580 sec, at which point Swift had to slew due to an observing constraint and the location went out of the BAT FoV. The time-averaged spectrum from T-38.98 to T+95.17 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.39 +- 0.06. The fluence in the 15-150 keV band is 6.8 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+0.88 sec in the 15-150 keV band is 1.8 +- 0.3 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/533060/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13734 SUBJECT: GRB 120909A: Swift-XRT refined Analysis DATE: 12/09/09 15:55:07 GMT FROM: Phil Evans at U of Leicester V. Mangano (INAF-IASFPA), A. Melandri (INAF-OAB), M.C. Stroh (PSU), D.N. Burrows (PSU), J.A. Kennea (PSU), K.L. Page (U. Leicester), C. Pagani (U. Leicester), A.P. Beardmore (U. Leicester), B. Sbarufatti (INAF-OAB/PSU) and S. Immler report on behalf of the Swift-XRT team: We have analysed 9.3 ks of XRT data for GRB 120909A (Immler et al. GCN Circ. 13727), from 3.3 ks to 33.3 ks after the BAT trigger. The data comprise 173 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN. Circ 13732). The light curve can be modelled with a power-law decay with a decay index of alpha=1.19 (+/-0.06). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.04 (+/-0.09). The best-fitting absorption column is 1.9 (+0.8, -0.7) x 10^22 cm^-2, at a redshift of 3.93, in addition to the Galactic value of 6.5 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 3.5 x 10^-11 (4.7 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Galactic foreground: 6.5 x 10^20 cm^-2 Intrinsic column: 1.9 (+0.8, -0.7) x 10^22 cm^-2 at z=3.93 Photon index: 2.04 (+/-0.09) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00533060. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13735 SUBJECT: GRB 120909A: Swift/UVOT Detection DATE: 12/09/09 18:02:19 GMT FROM: Alice Breeveld at MSSL-UCL A. A. Breeveld (MSSL-UCL) and S. Immler (CRESST/GSFC/UMD) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 120909A 3308 s after the BAT trigger (Immler et al., GCN Circ. 13727). A source consistent with the optical position (Sudilovsky et al. GCN Circ. 13729), is detected in the initial UVOT exposures. 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 white 3308 4690 344 20.75 ± 0.20 v 3465 16690 1261 >20.2 b 4285 23216 937 >21.5 u 4080 22450 1848 >21.4 w1 3875 21536 1968 >21.6 m2 3670 17445 1820 >21.4 w2 4696 15776 1082 >21.6 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: 13736 SUBJECT: Konus-Wind observation of GRB 120909A DATE: 12/09/09 18:28:23 GMT FROM: Dmitry Frederiks at Ioffe Institute 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 120909A (Swift-BAT trigger #533060: Immler et al., GCN 13727; Ukwatta et al., GCN 13733) was detected by Konus-Wind in the waiting mode starting at 6069 s UT (01:41:09), ~54s before the T0(BAT). The burst light curve shows a multi-peaked structure with a total duration of ~115s. The K-W light curve of this burst is available at http://www.ioffe.rssi.ru/LEA/GRBs/GRB120909A/ As observed by Konus-Wind, the burst had a fluence of (2.3 ± 0.2)x10-5 erg/cm2 and a peak energy flux, measured on the 2.944-s scale, of (6.1 ± 0.8)x10-7 erg/cm2 (both in the 20 - 1500 keV energy range). Modelling the K-W 3-channel time-integrated spectrum (from T0(BAT)-54s to T0(BAT)+61 s) by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) yields alpha = -1.23 ± 0.04, and Ep = 335 ± 25 keV Assuming X-Shooter redshift of z=3.93 (Hartoog et al., GCN 13730) and a standard cosmology model with H_0 = 71 km/s/Mpc, Omega_M = 0.27, Omega_Lambda = 0.73: the isotropic energy release E_iso is (6.9 ± 0.5)x10^53 erg, the isotropic peak luminosity L_iso_max is (9.0 ± 1.2)x10^52 erg/s, and Ep_rest is (1650 ± 120) keV. All the quoted errors are estimated at the 1 sigma confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13737 SUBJECT: GRB 120909A: Fermi GBM observation DATE: 12/09/09 19:49:34 GMT FROM: Vandiver Chaplin at UAH/Fermi-GBM V.Chaplin (UAH) reports on behalf of the Fermi GBM Team: At 01:41:22.40 UT on 09 September 2012, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 120909A (trigger 368847685 / 120909070), which was also detected by the Swift/BAT (Immler et al. 2012, GCN 13727) The GBM on-ground location is consistent with the Swift position. The angle to the Fermi LAT boresight is 66 degrees. The GBM light curve consists of several peaks between T0 and T0+100 seconds, with a total duration (T90) of about 112 s (50-300 keV). The time-averaged spectrum from T0-2.8 s to T0+104.7 s is best fit by a power law with exponential cutoff having an index of -1.3 +/- 0.1 and cutoff energy 370 +/- 140 keV. The event fluence (10-1000 keV) in this time interval is (2.1 +/- 0.2)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+3.26 s in the 10-1000 keV band is 3.0 +/- 0.2 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: 13738 SUBJECT: GRB 120909A: Pi of the Sky upper limits DATE: 12/09/09 21:17:21 GMT FROM: Lech Wiktor Piotrowski at U Warsaw T.Batsch,A.Cwiek,A.Majcher,A.Majczyna,K.Nawrocki,M.Sokolowski,G.Wrochna (NCBJ, Swierk), M.Cwiok,L.W.Piotrowski,M.Zaremba,A.F.Zarnecki (University of Warsaw), K.Malek,L.Mankiewicz,R.Opiela,M.Siudek,V.Repei (CFT PAN), G.Kasprowicz (Warsaw University of Technology), from the "Pi of the Sky" collaboration ( http://grb.fuw.edu.pl ). The wide field "Pi of the Sky South" telescope, installed in the private observatory of Alain Maury in San Pedro de Atacama (http://grb.fuw.edu.pl/pi/index.html#spda_site.htm) observed coordinates of the GRB 120909A, starting 10 s exposure 94 s after the reported SWIFT BAT detection. No new source was identified. The limiting magnitude is 11.6, based on the reference star magnitudo in V filter. We acknowledge support received from Alain Maury at SPdA Observatory. This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13739 SUBJECT: GRB 120909A: TAROT La Silla observatory optical observations DATE: 12/09/10 09:07:00 GMT FROM: Alain Klotz at CESR-CNRS Klotz A. (IRAP-CNRS-OMP), Gendre B. (ASDC/INAF-OAR), Boer M. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report: We imaged the field of GRB 120909A detected by SWIFT (trigger 533060) with the TAROT robotic telescope (D=25cm) located at the European Southern Observatory, La Silla observatory, Chile. The observations started 40s after the GRB trigger (14s after the notice). The elevation of the field decreased from 54 degrees above horizon and weather conditions were good. The first image is trailed with a duration of 60.0s (see the description in Klotz et al., 2006, A&A 451, L39). We detect the optical transient discovered by Haislip et al. (GCNC 13728). Relative photometric analysis is done using R=14.37 for the star NOMAD1 0305-0869420 (R.A.=275.7585731 Decl=-59.4476147 J2000). The careful analysis of the trail is compatible with a constant magnitude of R=17.1 from T+40s to T+100s. There is not optical peak during the gamma peak at T+48s reported by Ukwatta et al. (GCNC 13733). After the trailed image, a technical problem caused the lost of images until T+439s. Following images have been acquired using the classical diurnal drift. Summary of the first observations is: Start Stop Rmag Error 40s 100s 17.1 0.1 (continuous photometry) 439s 529s 16.5 0.1 539s 629s 18.9 0.1 640s 729s 19.1 0.2 744s 834s 19.3 0.2 845s 935s 19.7 0.2 Magnitudes are not corrected for galactic dust extinction (which should be about 0.4 magnitude in the R band according to D. Schlegel et al. 1998ApJ...500..525S). This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13742 SUBJECT: GRB 120908A and GRB 120909A : Fermi/LAT upper limit DATE: 12/09/10 19:20:18 GMT FROM: Weikang Zheng at U.of Michigan Weikang Zheng and Carl Akerlof (Umich), report on behalf of the ROTSE collaboration: We analyzed Fermi/LAT data of GRB 120908A (Morii et al., GCN 13731) and GRB 120909A (Immler et al., GCN 13727) as a follow-up of routine search in Swift trigger catalogs in our LAT data processing pipeline using both the matched filter technique (Akerlof et al. 2010, ApJ, 725, L15; 2011 ApJ, 726, 22; 2012, arXiv:1205.3066; Zheng et al. 2012, ApJ 745,72; ApJ, 756, 64) and likelihood method. We do NOT detect high energy photon emission from both methods in the two GRBs. A standard data selection method is applied when extracting the LAT photon data with energy E > 100 MeV, and a duration of T0 - T0+47.5s after the trigger. A zenith angle cut of <105 degree is applied to all photons. For GRB 120908A, the burst location was about 72 degrees from the LAT boresight, and the zenith angle was about 64 degrees at trigger time. Using the likelihood method, we estimated the upper limit in LAT energy range (0.1 - 10 GeV) is 8.3e-09 (photons cm^-2 s^-1) by assuming a spectral index of -2.2. The pipeline result of GRB 120908A is given in the following link: http://www.rotse.net/LAT/SwiftTriggers/368836516/ For GRB 120909A, the burst location was about 65 degrees from the LAT boresight, and the zenith angle was about 98 degrees at trigger time. Using the likelihood method, we estimated the upper limit in LAT energy range (0.1 - 10 GeV) is 2.0e-08 (photons cm^-2 s^-1) by assuming a spectral index of -2.2. The pipeline result of GRB 120909A is given in the following link: http://www.rotse.net/LAT/SwiftTriggers/368847726/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13776 SUBJECT: Corrections to the Fermi-LAT upper limits for GRB 120807A, 120908A, 120909A, and 120911A DATE: 12/09/17 21:22:46 GMT FROM: Weikang Zheng at U.of Michigan Weikang Zheng and Carl Akerlof (Umich), report on behalf of the ROTSE collaboration (the authors are not affiliated with the Fermi Collaboration), The recent GCN Circulars we reported about Fermi-LAT upper limits for GRB 120807A (GCN 13608), 120908A (GCN 13742), 120909A (GCN 13742), and 120911A (GCN 13752) contain an error about the upper limits estimation due to a wrong method. We apologize for the confusion. We thank Giacomo Vianello from LAT group for pointing it out and making suggestion to correct it. We've updated our pipeline result with the appropriate method (see The Fermi LAT team, Ackermann et al., 2012, ApJ, 754, 121). We report the corrected upper limit result (100 MeV -300 GeV; T0-T0 +47.5s) for the 4 GRBs again: GRB 120807A : 5.42e-05 ph/cm2/s GRB 120908A : 1.79e-04 ph/cm2/s GRB 120909A : 8.70e-05 ph/cm2/s GRB 120911A : 3.81e-05 ph/cm2/s