//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8473 SUBJECT: GRB 081104: Swift detection of a burst DATE: 08/11/04 09:53:20 GMT FROM: Ann M. Parsons at NASA/GSFC/Swift A. M. Parsons (GSFC), A. P. Beardmore (U Leicester), P. J. Brown (PSU), P. A. Evans (U Leicester), C. Gronwall (PSU), C. Guidorzi (INAF-OAB), S. T. Holland (CRESST/USRA/GSFC), N. P. M. Kuin (MSSL), V. La Parola (INAF-IASFPA), V. Mangano (INAF-IASFPA), J. Mao (INAF-OAB), P. T. O'Brien (U Leicester), J. P. Osborne (U Leicester), K. L. Page (U Leicester), P. Romano (INAF-IASFPA), T. N. Ukwatta (GSFC/GWU) and H. Ziaeepour (UCL-MSSL) report on behalf of the Swift Team: At 09:34:42 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 081104 (trigger=333666). The BAT on-board calculated location is RA, Dec 100.485, -54.732 which is RA(J2000) = 06h 41m 56s Dec(J2000) = -54d 43' 55" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multiple peaked structure with a duration of about 30 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~10 sec after the trigger. Due to an observing constraint, Swift will not slew until T0+40.5 minutes. There will be no XRT or UVOT data until this time. Burst Advocate for this burst is A. M. Parsons (parsons 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.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8474 SUBJECT: GRB 081104: Swift-XRT position DATE: 08/11/04 10:42:53 GMT FROM: Vanessa Mangano at INAF-IASFPA V. Mangano, V. La Parola (INAF-IASF PA), P. Evans (U. Leicester) report on behalf the Swift XRT Team: Swift slewed to the target (trigger=333666, Parsons et al., GCN Circ. 8473) at about 10:14:00 UT. Using promptly downlinked XRT data we find an uncatalogued source located at RA,Dec = 100.4835, -54.7211 which is equivalent to: RA (J2000.0) = 06 41 56.04 DEC (J2000.0) = -54 43 15.9 with an uncertainty of 4.04 arcsec (radius, 90% containment). This location is 39.4 arcsec from the BAT position, inside the BAT error circle. This is an official product of the Swift XRT Team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8475 SUBJECT: GRB 081104 : Faulkes Telescope South observations DATE: 08/11/04 13:58:03 GMT FROM: Andrea Melandri at Liverpool John Moores U A. Melandri, D.F. Bersier, M. Burgdorf, C.G. Mundell, R.J. Smith, I.A. Steele (Liverpool JMU) on behalf of a larger collaboration report: On 2008 November 04 on 12:13 UT we observed the field of GRB 081104 (trigger = 333666, Parsons et al., GCN 8473) with the robotic 2m Faulkes Telescope South located in Australia. We do not detect any fadind optical source within the XRT error circle (Mangano et al., GCN 8474) down to the following limit: Dt_mid T_exp Filter Mag_lim [hr] [min] =========================================== 2.89 30.0 R > 21.9 =========================================== Limiting magnitude has been estimated using the R2 magnitude of the USNO-B1 catalogue. The reported value is not corrected for the Galactic extinction. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8478 SUBJECT: GRB081104: Swift/UVOT Upper Limits DATE: 08/11/04 20:35:43 GMT FROM: Peter Brown at PSU P. J. Brown, C. A. Swenson (PSU), S. T. Holland, and A. M. Parsons (GSFC), on behalf of the Swift/UVOT team. The Swift Ultra-Violet/Optical Telescope (UVOT) began settled observations of GRB 081104 (trigger 333666) 2638 seconds after the BAT trigger (Parsons et al., GCN Circ. 8473). No afterglow is detected at the XRT position (Mangano et al., GCN Circ. 8474) in any filter. The limiting magnitudes (3-sigma in 5" radius apertures) in each of the UVOT filters are as follows: Filter T_start(s) T_stop(s) Exp(s) Mag UL (3sig) white 2638 3882 209 >21.1 v 2794 9582 1082 >20.5 b 3614 3814 197 >20.4 u 3409 3609 197 >20.1 uvw1 3204 3404 197 >19.8 uvm2 2999 9874 479 >20.1 uvw2 2788 5368 197 >19.9 The values quoted above are in the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627). They are not corrected for the expected Galactic extinction corresponding to a reddening of E(B-V)=0.11 mag in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8479 SUBJECT: GRB 081104: Swift-BAT refined analysis DATE: 08/11/04 22:39:17 GMT FROM: Ann M. Parsons 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), K. McLean (GSFC/UMD), 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-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 081104 (trigger #333666) (Parsons, et al., GCN Circ. 8473). The BAT ground-calculated position is RA, Dec = 100.500, -54.722 deg which is RA(J2000) = 06h 42m 00.0s Dec(J2000) = -54d 43' 17.4" with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 32%. The BAT mask-weighted light curve shows a single FRED peak. T90 (15-350 keV) is 59.1 +- 13.9 sec (estimated error including systematics). The time-averaged spectrum from T-23.5 to T+51.2 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.00 +- 0.14. The fluence in the 15-150 keV band is 2.0 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+13.54 sec in the 15-150 keV band is 1.0 +- 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/333666/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8480 SUBJECT: GRB 081104: Enhanced Swift-XRT position DATE: 08/11/05 08:02:38 GMT FROM: Phil Evans at U of Leicester A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team. Using 4796 s of XRT Photon Counting mode data and 6 UVOT images for GRB 081104, 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 = 100.4886, -54.7199 which is equivalent to: RA (J2000): 06h 41m 57.26s Dec (J2000): -54d 43' 11.5" 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 http://www.swift.ac.uk/xrt_positions/Goad.pdf), the current algorithm is an extension of this method. This circular was automatically generated, and is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8481 SUBJECT: GRB 081104: refined XRT analysis DATE: 08/11/05 11:11:44 GMT FROM: Vanessa Mangano at INAF-IASFPA V. Mangano, V. La Parola, B. Sbarufatti (INAF-IASF PA) report on behalf the Swift-XRT Team: Swift XRT follow-up observation of the field of GRB 081104 (trigger=333666, Parsons et al., GCN Circ. 8473) started on 2008 11 04 at 10:18:45 UT (about 40 min after the trigger). We have analysed the first four orbits of PC mode XRT data accumulated from T+2640 s to T+22153 s (6.5 ks exposure). The light curve of the X-ray source given in Mangano e. at, GCN Circ. 8474 shows a power-law decay with slope -1.0 +/- 0.2, with an initial count rate at the level of 0.1 counts/s. If decaying at this rate the source will reach a count rate level of 3.e-3 counts/s at T+24 hours. The average spectrum of the source have been fitted with Cash statistics. It can be modeled with a highly absorbed power law, with NH=(1.5 +/ -0.4)e22 cm^-2 (significantly in excess with respect to the Galactic absorption along the line of sight, of 7.0e20 cm^-2; Kalberla et al. 2005) and a photon index of 5.2 +/- 1.0 (C-statistic=84.4 with 93 bins). With the power law fit, the average observed (unabsorbed) flux in the 0.3-10 keV energy range is of 8.0e-13 (1.9e-10) erg cm^-2 s^-1. This is an official product of the Swift-XRT Team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8482 SUBJECT: GRB 081104: GROND Detection of the Optical/NIR Afterglow Candidate? DATE: 08/11/05 11:23:12 GMT FROM: Jochen Greiner at MPI C. Clemens, T. Kruehler, J. Greiner, R. Filgas, A. Yoldas (all MPE Garching), A. Kupcu Yoldas (ESO) and G. Szokoly (Eoetvoes Univ., Budapest) report on behalf of the GROND team: We observed the field of GRB 081104 (Swift trigger 333666; Parsons et al., GCN #8473) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPI/ESO telescope at La Silla Observatory (Chile). Observations started at 07:43 UT on November 5th, 2008, 22.1 hr after the GRB trigger. They were performed at an average seeing of 1.0" and at an average airmass of 1.1. We found a single point source at the edge of the astrometrically corrected 1.6'' Swift-XRT error circle reported by Beardmore et al. (GCN #8480) at RA (J2000.0) = 06h 41m 57.13s DEC (J2000.0) = -54d 43' 09.9'' with an uncertainty of 0.5". Based on the first 25 min of total exposures in g'r'i'z' and 20 min in JHK, we estimate preliminary magnitudes (all in AB system) of g' ~ 22.7 mag, r' ~ 22.6 mag, i' ~ 21.8 mag, z' ~ 21.7 mag, J ~ 21.2 mag, H > 21.1 mag and K > 20.0 mag with errors of +/- 0.2. These magnitudes are calibrated against GROND zeropoints as well as 2MASS field stars, and are not corrected for the galactic foreground extinction of E(B-V)= 0.1 The extinction-corrected spectral energy distribution is only marginally consistent with a power law, so at present (without proper calibration) we cannot distinguish between a foreground star, an afterglow, or a host. No statement about variability can be made at this point either. We note that a very faint object is also visible on the POSS-IIN plate at this location. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8493 SUBJECT: GRB 081104: GROND found no Optical/NIR Afterglow DATE: 08/11/07 09:38:11 GMT FROM: Christian Clemens at MPE C. Clemens, T. Kruehler, J. Greiner (all MPE Garching) and G. Szokoly (Eoetvoes Univ., Budapest) report on behalf of the GROND team: We observed the field of GRB 081104 for a second time at 04:29 UT on November 6th, 2008, 42.9 hr after the GRB trigger with 73.0 min of total exposures in g'r'i'z' and 64.0 min in JHK. Observations were performed at an average seeing of 1.7". We still detect the previously reported source (Clemens et al., GCN #8482) with magnitudes identical within the errors to our first epoch observations. Therefore, this object is most likely not the afterglow of GRB 081104. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8635 SUBJECT: Radio observation of GRB 081104 with ATCA DATE: 08/12/08 04:02:10 GMT FROM: Aquib Moin at CIRA/ATNF Aquib Moin (Curtin Institute of Radio Astronomy / Australia Telescope National Facility), Steven Tingay (Curtin Institute of Radio Astronomy), Chris Phillips (Australia Telescope National Facility), Gregory Taylor (University of New Mexico), Mark Wieringa (Australia Telescope National Facility) and Ralph Martin (Perth Observatory) report: We observed the GROND position of the GRB 081104 optical afterglow (GCN 8482) at 4.800 and 4.928 GHz with the Australia Telescope Compact Array (ATCA) between 01:15:05 UT, November 24, 2008 and 20:35:30 UT November 25, 2008. We did not detect a radio source at the optical afterglow position of the GRB 081104 (GCN 8482). The data at 4.800 and 4.928 GHz were merged and the radio flux density at the afterglow position found out to be -0.142 +/- 0.152 mJy/beam (1-sigma). The Australia Telescope Compact Array (/ Parkes telescope / Mopra telescope / Long Baseline Array) is part of the Australia Telescope which is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO. See the 4.800 & 4.928 GHz combined image at: http://cira.ivec.org/dokuwiki/doku.php/grb/grb081104_field_image