//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9983 SUBJECT: GRB 091003A: Fermi GBM detection DATE: 09/10/03 11:42:08 GMT FROM: Arne Rau at MPE Arne Rau (MPE) reports on behalf of the Fermi GBM Team: "At 04:35:45.58 UT on 03 September 2009, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 091003A (trigger 276237347 / 091003191). The on-ground calculated location, using the GBM trigger data, is RA = 251.1, DEC = 37.2 (J2000 degrees, equivalent to 16h 44m, 37d 12'), with an uncertainty of 1.0 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). The angle from the Fermi LAT boresight is 13 degrees. This burst was also independently detected by INTEGRAL SPI-ACS. The GBM light curve consists of multiple peaks with a duration (T90) of about 21.1 +/- 0.5s (8-1000 keV). The time-averaged spectrum from T0-0.384s to T0+23.168s is best fit by a Band function with Epeak = 486.2 +/- 23.6 keV, alpha = -1.13 +/- 0.01, and beta = -2.64 +/- 0.24 (chi squared 851 for 611 d.o.f.). The event fluence (8-1000 keV) in this time interval is (3.76 +/- 0.04)E-05 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+18.048 s in the 8-1000 keV band is 31.8 +/- 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: 9985 SUBJECT: GRB 091003A: Fermi LAT detection DATE: 09/10/03 21:46:38 GMT FROM: Julie McEnery at UMBC/GSFC Julie McEnery (NASA/GSFC), Jim Chiang (SLAC) and Yoshitaka Hanabata (Hiroshima) report on behalf of the Fermi LAT team: At 04:35:45 (UT) on 03 Oct 2009, the Fermi Large Area Telescope (LAT) detected gamma rays from the long GRB 091003, which was triggered and located by the Fermi Gamma-ray Burst Monitor (GBM) (trigger 2756237347 / 091003191, GCN9983). The angle of the GBM best position (RA, Dec= 251.1, 37.2) with respect to the LAT boresight was ~13 degrees at the time of the trigger, which is close to the center of our field of view. This burst was bright enough to initiate a Fermi spacecraft repointing maneuver resulting in 5 hours of pointed observations of the burst position following the GBM trigger. The data from the Fermi LAT shows a significant increase in the event rate after the GBM trigger that is spatially and temporally correlated with the GBM emission with high significance (>10 sigma). The best LAT on-ground localization is found to be (RA, Dec = 251.39, 36.58) with a 90% containment radius of 0.21 deg (statistical; 68% containment radius: 0.15 deg, preliminary systematic error is less than 0.1 deg) which is consistent with the GBM localization. A Swift TOO request has been issued. Further analysis is ongoing. The point of contact for this burst is Julie McEnery : julie.mcenery@nasa.gov The Fermi LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden. This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9986 SUBJECT: GRB 091003: Swift XRT analysis DATE: 09/10/04 00:44:01 GMT FROM: Rhaana Starling at U of Leicester R.L.C. Starling and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team: The Swift X-ray Telescope (XRT) observed the Fermi GBM/LAT and Integral-detected GRB 091003 (Rau GCN Circ. 9983; McEnery et al. GCN Circ. 9985) on 2009 October 3 at 20:07:28 UT, 15.5 hours after the Fermi trigger. In 2.5 ks of photon counting mode data we detect an uncatalogued X-ray source at RA, Dec = 251.52047, 36.62548 degrees, which is equivalent to: RA (J2000) = 16:46:04.9 Dec (J2000) = +36:37:31.74 with an uncertainty of 3.7 arcsec (radius, 90% containment). This is 6.85 arcmin from the Fermi LAT position and within its error circle. A spectrum formed from these data can be fit with an absorbed power law of photon index 1.7+/-0.3, with nH < 2e21 cm-2, and has an observed 0.3-10 keV count rate of 0.087+/-0.007 count/s corresponding to a flux of 3.6e-12 erg/cm2/s. At this stage we do not have enough data to tell if the source is fading. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9987 SUBJECT: GRB 091003: Swift UVOT Detection of a Candidate UV Afterglow DATE: 09/10/04 02:21:18 GMT FROM: Caryl Gronwall at PSU/Swift-UVOT C. Gronwall (PSU) and R.L.C. Starling (U. Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 091003 approximately 15.5 hours after the Fermi/GBM trigger (Rau, GCN Circ. 9983). In a 885 sec observation in the uvw2 filter, we find a faint candidate fading UV afterglow within the XRT error circle (Starling & Beardmore, GCN Circ. 9986). The estimated magnitude is 21.02 +/- 0.27. This value is 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). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9988 SUBJECT: GRB 091003: UVOT-enhanced XRT position DATE: 09/10/04 12:10:23 GMT FROM: Rhaana Starling at U of Leicester R.L.C. Starling, P.A. Evans, A.P. Beardmore and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team: Using 4881 s of XRT Photon Counting mode data and 11 UVOT images for GRB 091003, 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 = 251.51980, 36.62470 which is equivalent to: RA (J2000): 16 46 4.75 Dec (J2000): +36 37 29.0 with an uncertainty of 1.7 arcsec (radius, 90% confidence). The UV counterpart reported in Gronwall & Starling (GCN Circ.9987) is consistent with this position. 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 is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9989 SUBJECT: GRB 091003: Skynet/DSO Observations DATE: 09/10/04 18:14:15 GMT FROM: Josh Haislip at U.North Carolina J. Haislip, D. Reichart, A. Smith, D. Caton, L. Hawkins, K. Ivarsen, A. LaCluyze, A. Foster, J. Moore, A. Oza, M. Schubel, J. Styblova, A. Trotter, J. A. Crain, and M. Nysewander report: Skynet observed the Fermi/LAT localization (McEnery, Chiang & Hanabata, GCN 9985) of GRB 091003 (Rau, GCN 9935) with the 14" Dark Sky Observatory telescope in North Carolina beginning 20.2 hours after the trigger in BVRI. We do not detect the afterglow (Starling & Beardmore, GCN 9986; Gronwall & Starling, GCN 9987). Stacking only images that increase the limiting magnitude yields: 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) 21.0 DSO-14 16 x 80 V 19.6 58 SDSS 7 0.076 0.000 21.0 DSO-14 17 x 80 B 19.5 33 SDSS 7 0.087 0.001 21.0 DSO-14 16 x 80 R 19.8 64 SDSS 7 0.064 0.000 21.0 DSO-14 16 x 80 I 19.3 45 SDSS 7 0.049 0.000 * Transformed using Jester et al., 2005, ApJ, 130, 873. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9990 SUBJECT: GRB 091003: Swift/UVOT Detection of an Optical Afterglow DATE: 09/10/04 23:42:48 GMT FROM: Tyler Pritchard at PSU T. A. Pritchard (PSU) , E.A. Hoversten (PSU), and R.L.C. Starling (U. Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 091003 approximately 15.5 hours after the FERMI/GBM Trigger (Rau, GCN Circ. 9983) A faint source is detected with 3.9-sigma confidence in the summed UVOT observations at the Swift UVOT-enhanced XRT position (R.L.C. Starling, et al. GCN Circ. 9988). The observed magnitudes and upper limits using the UVOT photometric system (Poole etal. 2008, MNRAS, 383, 627) for the initial exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag ======================================================================= w2 56820 64169 1150 21.08 ± 0.28 (3.9 sigma) w1 103712 104474 750 20.70 ± 0.32 (3.4 sigma) b 92252 92954 685 20.80 ± 0.26 (4.1 sigma) m2 98013 98715 691 > 21.63 v 86432 87195 741 > 20.27 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). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9991 SUBJECT: GRB 091003: Swift-XRT confirmation of fading afterglow DATE: 09/10/05 07:59:40 GMT FROM: Kim Page at U.of Leicester K.L. Page, R.L.C. Starling, P.A. Evans & A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team: We have now collected 15 ks of Swift-XRT Photon Counting mode data on the Fermi burst GRB 091003 (Rau, GCN Circ. 9983; McEnery, Chiang & Hanabata, GCN Circ. 9985), between 56 and 168 ks after the trigger. The light-curve is fading, with alpha = 1.02 +0.21/-0.20. We therefore confirm that the source given by Starling et al. in GCN Circ. 9986 and 9988 is, indeed, the X-ray afterglow. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9994 SUBJECT: Konus-Wind observation of GRB 091003A DATE: 09/10/05 10:14:24 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 bright GRB 091003A (Fermi-GBM trigger 276237347 / 091003191: Rau, GCN 9983) localized by Fermi-LAT (McEnery et al., GCN 9985) triggered Konus-Wind at T0=16543.801 s UT (04:35:43.801). The burst light curve shows a multipeaked structure with a total duration of ~23 s. As observed by Konus-Wind the burst had a fluence of 3.44(-0.19, +0.20)x10^-5 erg/cm2, and a 16-ms peak flux measured from T0+18.592 s of (1.68 +/- 0.32)x10^-5 erg/cm2/s (both in the 20 keV - 2 MeV energy range). The time-integrated spectrum of the burst (from T0 to T0+26.880 s) is well fitted (in the 20 keV - 2 MeV range) by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep), with alpha = -1.04 +/- 0.06, and Ep = 381(-36, +44) keV (chi2 = 58.4/61 dof). Fitting by GRB (Band) model yields the same alpha and Ep, and only an upper limit on the high energy photon index: beta < -2.22 (chi2 = 56.2/60 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/GRB091003_T16543/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9995 SUBJECT: GRB 091003: WHT ACAM observations DATE: 09/10/05 17:11:44 GMT FROM: Klaas Wiersema at U of Leicester K. Wiersema, N. Tanvir (Leicester), A. Levan (Warwick) and C. Benn (ING) report on behalf of a larger collaboration: We observed the afterglow of Fermi GRB 091003 (Rau GCN 9983; McEnery et al GCN 9985; Starling & Beardmore GCN 9986) with the William Herschel Telescope, using the ACAM instrument. We took a 60 and a 250 second exposure in imaging mode, starting at 21:11 UT, October 4 (1.69 days after burst). The afterglow is clearly detected, with r = 21.33 +/- 0.11 (calibrated to SDSS field stars), at position: RA (J2000) = 16:46:04.687 Dec (J2000) = +36:37:30.76 with uncertainty 0.3 arcseconds. We obtained spectroscopy with ACAM immediately after, at high airmass. Two 900 second exposures were obtained using the 400V grism and a 1 arcsecond slit. Faint continuum emission is detected over the 4000-9300 A range. No strong absorption or emission lines are detected. The detection of continuum at 4000A gives a upper limit to the redshift of 2.3. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9997 SUBJECT: GRB 091003: Lick observations and possible SDSS host galaxy DATE: 09/10/06 22:17:22 GMT FROM: Daniel Perley at U.C. Berkeley D. A. Perley, J. Choi, A. J. L. Morton, and M. Ganeshalingam (UC Berkeley) report: We observed the position of Fermi GRB 091003 (Rau et al., GCN9983) using the Nickel 1m telescope at Lick Observatory on the night of 2009-10-06 (UT) starting at 04:06 for a series of five 600-second exposures in R-band. The afterglow (Starling and Beardmore, GCN 9986; Gronwall and Starling, GCN 9987) is marginally detected in the combined frame. Calibrating to nearby SDSS stars transformed to R-band using the equations of Lupton et al. (2005) we estimate a magnitude of R = 21.2 +/- 0.4 (t_mid = 3.00 days) This suggests only limited fading since the observations of Wiersama et al. (GCN 9995). Further, we note that a source coincident with this position is detected in the SDSS survey imaging. The object (SDSS J164604.70+363731.1) has a magnitude of r = 23.2 and is classified as a star, but could represent the host galaxy of this event. A low redshift would also be consistent with the absence of absorption signatures in the spectrum of Wiersema et al. and with the Swift UVW2 detection (Pritchard et al., GCN 9990). We encourage further observations, in particular additional spectroscopy, of this object. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9998 SUBJECT: GRB 091003A: Suzaku WAM observation of the prompt emission DATE: 09/10/07 02:43:10 GMT FROM: Kenta Kono at Miyazaki U K. Kono, E. Sonoda, N. Ohmori, K. Noda, 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 091003A (Fermi-GBM trigger 276237347 / 091003191 ; A. Rau et al., GCN 9983 ; J. McEnery et al., GCN 9985) triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 04:35:45.586 UT (=T0). The observed light curve shows a multi-peaked structure starting at T0-2 s and ending at T0+23 s, with a total duration (T90) of about 21 s. The fluence in 100 - 1000 keV was 1.98(-0.14, +0.08)x10-5 erg/cm2. The 1-s peak flux measured from T0+18 s was 7.53(-1.28, +0.39) photons/cm2/s in the same energy range. Preliminary result shows that the time-averaged spectrum from T0-2 s to T0+23 s is well fitted by a power-law with exponential cutoff model: dN/dE ~ E^{-alpha} * exp(-(2-alpha)*E/Epeak) with alpha 1.19(-0.36, +0.29), and Epeak 576(-72, +106) keV (chi2/d.o.f. = 21.5/24). Due to the brightness of this burst, a 3% systematic error was added for low energy channels. All the quoted errors are at 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 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10031 SUBJECT: GRB 091003: Gemini-N redshift of possible host galaxy DATE: 09/10/18 19:20:08 GMT FROM: Antonino Cucchiara at PSU A. Cucchiara, D. B. Fox (PSU), S. B. Cenko (U. Berkeley), N. Tanvir (U. Leicester), E. Berger (Harvard U.) report on behalf of a larger collaboration: "On October 17.20 UT we observed the possible host galaxy of the Fermi/LAT GRB 091003 (McEnery at al, GCN 9985 and Perley et al. GCN 9997) with Gemini GMOS-N. We took a sequence of 2 spectra of 1800s each covering the 6000-10000A wavelength range. The spectra clearly show emission lines which we interpreted as [OII]3727, Hbeta and we resolved the [OIII]4959,5007 doublet. All these identifications are consistent with redshift z = 0.8969 for this galaxy. The galaxy is detected in our 300s R-band acquisition image. The estimated magnitude, calibrated using 3 SDSS stars is: R = 22.65 +- 0.05 mag This value is brighter than the cataloged magnitude, which may indicate a contribution of the afterglow. After subtracting the contribution of the galaxy we derive an estimate of the OT flux, R = 23.65 +- 0.05 mag. We thank the Gemini staff for performing these observations." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10032 SUBJECT: GRB 091003: Possible Supernova Component DATE: 09/10/18 19:56:31 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC S. T. Holland (CRESST/USRA/GSFC) reports: The excess light from the z = 0.8969 host galaxy candidate for GRB 091003 (Cucchiara et al. 2009, GCNC 10031) correspond to a rest-frame B-band absolute magnitude of approximately M_B = -20 mag. This is approximately consistent with the peak rest-frame B-band absolute magnitude of SN1998bw. The Cucchiara et al. (2009, GCNC 10031) observation was taken on 2009 Oct 17, which corresponds to approximately seven days after the burst in the rest frame, which is approximately the expected time of maximum light for a SN Ib/c. Therefore, we suggest that the excess light seen in this galaxy may be due to a supernova component of GRB 091003. The lack of an observed optical afterglow at earlier times supports this interpretation. Further spectroscopic observations are encouraged to test this hypothesis. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10033 SUBJECT: Fwd: GRB 091003: Possible Supernova Component Retraction DATE: 09/10/18 20:04:51 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC S. T. Holland (CRESST/USRA/GSFC) reports: I would like to retract GCNC 10032 (Holland 2009). It was sent in error due to a confusion between GRB 091003 and GRB 091010. I apologize for the error and any confusion that it may have caused.