This file contains bother GRBs: 080218A and 080218B //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7313 SUBJECT: GRB 080218: Swift detection of a burst DATE: 08/02/18 20:18:57 GMT FROM: Scott Barthelmy at NASA/GSFC H. Ziaeepour (UCL-MSSL), S. D. Barthelmy (GSFC), J. R. Cummings (NASA/UMBC), P. A. Evans (U Leicester), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), W. B. Landsman (NASA/GSFC), K. M. McLean (GSFC/UMD), C. Pagani (PSU), D. M. Palmer (LANL), T. Sakamoto (NASA/UMBC), G. Sato (GSFC/ISAS), M. Stamatikos (NASA/ORAU), D. E. Vanden Berk (PSU), L. Vetere (PSU) and P. A. Ward (MSSL-UCL) report on behalf of the Swift Team: At 20:08:42 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 080218 (trigger=303609). Swift did not slew to the burst location because of the Sun observing constraint (34 deg from the Sun). The BAT on-board calculated location is RA, Dec 355.922, +12.175 which is RA(J2000) = 23h 43m 41s Dec(J2000) = +12d 10' 29" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a weak peak around T_0. The peak count rate was ~400 counts/sec (15-350 keV). Because this burst is in the Sun constraint until May, no XRT or UVOT data will be available. Burst Advocate for this burst is H. Ziaeepour (hz AT mssl.ucl.ac.uk). 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: 7314 SUBJECT: GRB 080218B: Swift detection of a burst DATE: 08/02/19 00:37:50 GMT FROM: David Palmer at LANL P. Schady (MSSL-UCL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), J. R. Cummings (NASA/UMBC), P. A. Evans (U Leicester), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), H. A. Krimm (GSFC/USRA), F. E. Marshall (NASA/GSFC), C. Pagani (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL), T. Sakamoto (NASA/UMBC), G. Sato (GSFC/ISAS), M. Stamatikos (NASA/ORAU), R. L. C. Starling (U Leicester), D. E. Vanden Berk (PSU) and P. A. Ward (MSSL-UCL) report on behalf of the Swift Team: At 23:57:47 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 080218B (trigger=303631). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 177.951, -53.100 which is RA(J2000) = 11h 51m 48s Dec(J2000) = -53d 06' 00" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of at least 12 sec, up to an interruption in the available data caused by a TDRSS gap. The peak count rate was ~1300 counts/sec (15-350 keV), at ~0 sec after the trigger. Using prompt downlinked data starting 931 s after the BAT trigger, we find a bright X-ray source located at RA, Dec 177.9560, -53.0960 which is RA(J2000) = 11 51 49.44 Dec(J2000) = -53 05 45.7 with an uncertainty of 3.0 arcsec (radius, 90% containment). This location is 18 arcseconds from the BAT on-board position, within the BAT error circle. UVOT took a finding chart exposure of 99 seconds with the White (160-650 nm) filter starting 551 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. The UVOT image covers 100% of the XRT error circle and has an estimated 3-sigma limiting magnitude of white = 20.6. No correction has been made for the expected extinction corresponding to a reddening of E(B-V) = 0.17 mag. Burst Advocate for this burst is P. Schady (ps AT mssl.ucl.ac.uk). 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: 7316 SUBJECT: GRB080218B: Watcher prompt limit DATE: 08/02/19 02:02:07 GMT FROM: Martin Jelinek at Inst.Astrophys.Andalucia,Granada J. French (UCD Dublin), M. Jelinek and Petr Kubanek (IAA CSIC Granada) and Antonio de Ugarte Postigo (ESO Santiago) on behalf of the Watcher collaboration report: "The 0.4 m telecope Watcher, located at Boyden observatory, South Africa, followed the Swift GRB 080218B (Schady et al. GCN 7314). 10s unfiltered (limmag = 16.0) images were obtained starting 60.4s after the GRB (18.3s after receiving the notification). We do not detect any new source in single nor combined images within the BAT or XRT errorbox." This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7317 SUBJECT: GRB 080218A, Swift-BAT refined analysis DATE: 08/02/19 03:24:29 GMT FROM: Takanori Sakamoto at NASA/GSFC E. Fenimore (LANL), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta (GWU), H. Ziaeepour (UCL-MSSL) (i.e. the Swift-BAT team): Using the data set from T-239 to T+303 sec from the recent telemetry downlink, we report further analysis of BAT GRB 080218A (trigger #303609) (Ziaeepour, et al., GCN Circ. 7313). The BAT ground-calculated position is RA, Dec = 355.941, 12.159 deg which is RA(J2000) = 23h 43m 45.8s Dec(J2000) = 12d 9' 34" with an uncertainty of 2.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 21%. The mask-weighted light curve shows three peaks at T-12 sec, T+0 sec, and T+9 sec. T90 (15-350 keV) is 27.6 +- 5.9 sec (estimated error including systematics). The time-averaged spectrum from T-12.8 to T+18.6 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.34 +- 0.35. The fluence in the 15-150 keV band is 6.3 +- 1.4 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T+1.22 sec in the 15-150 keV band is 1.4 +- 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/303609/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7318 SUBJECT: GRB 080218b, SMARTS optical/IR limits DATE: 08/02/19 03:55:24 GMT FROM: Bethany Cobb at Yale U B. E. Cobb, part of the larger SMARTS consortium, reports: Using the ANDICAM instrument on the 1.3m telescope at CTIO, we obtained optical/IR imaging of the error region of GRB 080218b (Schady et al. GCN 7314) with a mid-exposure time of ~3.1 hours post-burst (2008-02-19 03:03 UT). Total summed exposure times amounted to 18 minutes in I and 15 minutes in J. No source is detected at the position of the X-ray afterglow (Schady et al. GCN 7314) to approximate limiting magnitudes of I > 21.1 and J > 18.7. Magnitudes are calibrated using USNO-B1.0 values for I, and 2MASS values for J. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7319 SUBJECT: GRB 080218B: GROND upper limits DATE: 08/02/19 04:15:59 GMT FROM: Jochen Greiner at MPI A. Rossi (Tautenburg Obs.), J. Greiner, A. K"upc"u Yoldas, and A. Yoldas (MPE Garching) report for the GROND team: We observed the field of GRB 080218B, Swift trigger 303631 (Schady et al. 2008, GCN Circ. 7314) simultaneously in grizJHK with GROND (Greiner et al. 2008, astro-ph/0801.4801) mounted at the 2.2m MPI/ESO telescope at La Silla (Chile). Observations started at 00:37, 379 min after the GRB. At this time, the GRB location was becoming visible at 20 degrees above horizon. Through thin cirrus, we do not detect any source inside the XRT error. We estimate the following limits: g'>24.2, r'>24.2, i'>23.7, z'>23.4, J>21.6, H>20.6, K>19.5, calibrated against USNO-B and 2MASS stars. These values are not corrected for the substantial foreground extinction. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7320 SUBJECT: GRB 080218B: Enhanced Swift-XRT position DATE: 08/02/19 06:16:07 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 311 s of overlapping XRT Photon Counting mode and UVOT V-band data for GRB 080218B, 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 = 177.95739, -53.09712 which is equivalent to: RA (J2000): 11h 51m 49.77s Dec (J2000): -53d 05' 49.6" with an uncertainty of 2.4 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 http://www.swift.ac.uk/xrt_positions/Goad.pdf). This circular was automatically generated, and is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7322 SUBJECT: GRB 080218B: REM NIR early upper limits DATE: 08/02/19 07:39:08 GMT FROM: Stefano Covino at Brera Astronomical Observatory S. Covino, P. D'Avanzo, L.A. Antonelli, D. Fugazza, L. Calzoletti, S. Campana, G. Chincarini, M.L. Conciatore, S. Cutini, V. D'Elia, F. D'Alessio, F. Fiore, P. Goldoni, D. Guetta, C. Guidorzi, G.L. Israel, E. Maiorano, N. Masetti, A. Melandri, E.J.A. Meurs, L. Nicastro, E. Palazzi, E. Pian, S. Piranomonte, L. Stella, G. Stratta, G. Tagliaferri, G. Tosti, V. Testa, S.D. Vergani, F. Vitali report on behalf of the REM team: The robotic 60-cm REM telescope located at La Silla (Chile) observed automatically the field of the GRB 080218B (Schady et al., GCN 7314). A preliminary analysis of the first set of H and K-band exposures does not reveal any afterglow candidate inside the refined XRT error box (Osborne et al., GCN 7320). The 3sigma upper limits of our images are H > 13.7 about 2 minutes after the burst and K > 12.6 about 8 minutes after the burst (calibrated against the 2MASS catalog). Further analysis is in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7323 SUBJECT: Swift/UVOT observations of GRB080218B DATE: 08/02/19 08:25:39 GMT FROM: Patricia Schady at MSSL/Swift P. Schady (MSSL-UCL) reports on behalf of the Swift-UVOT team The Swift-UVOT observed the field of GRB080218B starting 551 s after the BAT trigger (Schady et al., GCN 7314). No new source is detected within the refined XRT error circle (Osborne et al., GCN 7320) in any of the UVOT co-added observations down to the following 3-sigma upper limits: Filter Tmid (s) Exp (s) Upper Limit wh 4178 420 > 21.09 v 2955 494 > 19.87 b 4126 283 > 20.24 u 4098 294 > 19.98 uvw1 3984 294 > 19.77 uvm2 3868 313 > 19.67 uvw2 6056 281 > 19.91 where Tmid is the weighted mid time of the co-added observations. The values quoted above are not corrected for the expected Galactic extinction corresponding to a reddening of E(B-V)= 0.17 mag in the direction of the burst (Schlegel et al. 1998), //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7324 SUBJECT: GRB 080218B: Swift-XRT refined analysis DATE: 08/02/19 09:51:14 GMT FROM: Phil Evans at U of Leicester P.A. Evans, K.L. Page, A.P. Beardmore, J.P. Osborne (U Leicester) and P. Schady (MSSL-UCL) report on behalf of the Swift-XRT team: We have analysed the first four orbits of XRT data obtained for GRB 080218B (Schady et al., GCN Circ. 7314), totalling 4.6 ks in Photon Counting (PC) mode. Partly due to the proximity of Swift to the SAA, the observations did not start until 930 s after the trigger. The UVOT-enhanced XRT position was given in Osborne et al. (GCN Circ. 7320). The light curve shows a simple power-law decay, with an index of alpha=0.92 (+0.13/-0.11). A spectrum formed from all available data can be modelled with an absorbed power law, with gamma=2.46 (+0.53/-0.47) and a column density nH=5.17(+0.24/-0.18)e21 cm^-2, significantly in excess of the Galactic value of 1.35e21 cm^-2 (Kalberla et al. 2005). Given the excess absorption, the relation given in Grupe et al (2007) suggests that this burst lies at a redshift <3.3 (90% confidence). The 0.3-10 keV observed (unabsorbed) flux during the interval T0+1--25 ks is 5.72e-12 (1.48e-11) erg cm^-2 s^-1. If the light curve continues to decay at alpha=0.92, the XRT count rate at T0+24 hours will be 4.0e-3 count s^-1, which is equivalent to an observed (unabsorbed) 0.3-10 keV flux of 2.29e-13 (5.92e-13) erg cm^-2 s^-1. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7325 SUBJECT: GRB 080218B, Swift-BAT refined analysis DATE: 08/02/19 15:41:08 GMT FROM: Scott Barthelmy at NASA/GSFC H. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), C. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/UMBC), G. Sato (GSFC/ISAS), P. Schady (MSSL-UCL), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-198 to T+962 sec from recent telemetry downlinks, we report further analysis of BAT GRB 080218 (trigger #303631) (Schady, et al., GCN Circ. 7314). The BAT ground-calculated position is RA, Dec = 177.927, -53.086 deg, which is RA(J2000) = 11h 51m 42.4s Dec(J2000) = -53d 05' 11" with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 10%. The mask-weighted light curve shows a roughly triangular peak starting at ~T-3 sec, peaking at T+1 sec, and ending at ~T+7 sec. T90 (15-350 keV) is 6.2 +- 1.2 sec (estimated error including systematics). The time-averaged spectrum from T-0.8 to T+6.6 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.11 +- 2.44, and Epeak of 23.6 +- 14.6 keV (chi squared 49.02 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 5.1 +- 1.0 x 10^-7 erg/cm2 and the 1-sec peak flux measured from T+0.28 sec in the 15-150 keV band is 3.1 +- 0.6 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.63 +- 0.29 (chi squared 55.36 for 57 d.o.f.). 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/303631/BA/ We note that the fluence ratio in a simple power-law fit between the 25-50 keV band and the 50-100 keV band is 1.55. This fluence ratio is larger than 1.32 which can be achieved in the Band function of alpha=-1.0, beta=-2.5, and Epeak=30 keV. Thus, preliminary analysis shows that Epeak of the burst is very likely around or below 30 keV. Therefore the burst can be classified as an X-ray flash (e.g. Sakamoto et al. ApJ in press, arXiv:0801.4319). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7327 SUBJECT: ESO optical and NIR observations of GRB 080218B DATE: 08/02/22 16:51:29 GMT FROM: Paul Vreeswijk at Dark Cosmology Centre,U.of Copenhagen Paul Vreeswijk, Johan Fynbo, Bo Milvang-Jensen, Daniele Malesani, Jens Hjorth (DARK/NBI), Pall Jakobsson (U. Hertfordshire), Andreas Jaunsen (U. Oslo), Nial Tanvir (U. Leicester) report on behalf of a larger collaboration: The Swift localization of GRB 080218B (Schady et al., GCN 7314) was observed with FORS2 mounted at the VLT Antu telescope on Cerro Paranal in Rapid-Response Mode, and with SOFI at the NTT on La Silla. Starting at Feb 19, 1:03 UT (roughly 1 hour after the burst) VLT/FORS2 performed the imaging sequence R-I-z-V-B-R (30-150s per filter) through thin cirrus, at an airmass of 2.5, and with an effective seeing of 1.5". NTT/SOFI imaged the afterglow location at an airmass of 1.3-1.5 and in 1.4" seeing conditions in Ks-J-H-Ks (10 min. per filter), starting at Feb 19, 2:52 UT. No object is detected within the enhanced XRT error circle (Osborne et al., GCN 7320) down to the following limiting magnitudes (2 sigma): B>22.1, V>22.7, R>22.9, I>22.6, J>20.6, H>20.1 and Ks>19.4. The corresponding upper limit on the optical to X-ray spectral slope, beta_OX, is 0.24, rendering the burst dark according to the definition proposed by Jakobsson et al. (2004, ApJ, 617, L21). A spectrum of an object just outside the XRT error circle at R.A. 11:51:49.25, decl. -53:05:50.1 (J2000), shows it to be a Galactic star of type M6V. We acknowledge the excellent support of ESO's night astronomers at La Silla Paranal Observatory, and in particular that of Linda Schmidtobreick, Colin Snodgrass, Stephane Brillant and Lorenzo Monaco. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8466 SUBJECT: Radio observation of GRB 080218b with ATCA DATE: 08/11/03 01:41:02 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 SWIFT-BAT refined position of the GRB 080218b (GCN 7325) at 4.8 and 8.456 GHz with the Australia Telescope Compact Array (ATCA) on May 31, 2008 between 04:24:45 UT and 10:15:15 UT. We did not detect a radio source at the BAT position of the GRB 080218b (GCN 7325). The radio flux density at the GRB position is -0.286 +/- 0.252 mJy at 4.8 GHz, and -0.350 +/- 0.271 mJy at 8.456 GHz (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 field images at: http://cira.ivec.org/dokuwiki/doku.php/grb/grb_080218b_field_image_at_4.8_ghz http://cira.ivec.org/dokuwiki/doku.php/grb/grb_080218b_field_image_at_8.456_ghz