//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7894 SUBJECT: GRB 080623: Swift detection of a burst DATE: 08/06/23 10:43:00 GMT FROM: David Palmer at LANL T. N. Ukwatta (GSFC/GWU), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), O. Godet (U Leicester), S. T. Holland (CRESST/USRA/GSFC), S. D. Hunsberger (PSU), J. A. Kennea (PSU), A. Moretti (INAF-OAB), K. L. Page (U Leicester), D. M. Palmer (LANL), D. Perez (U Leicester), M. Perri (ASDC) and G. Stratta (ASDC) report on behalf of the Swift Team: At 10:25:28 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 080623 (trigger=315080). Swift did not immediately slew because of an Earth observing constraint. The BAT on-board calculated location is RA, Dec 237.660, -62.038, which is RA(J2000) = 15h 50m 38s Dec(J2000) = -62d 02' 16" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showes several overlapping peaks with a duration of about 25 sec. The peak count rate was ~2500 counts/sec (15-350 keV), at ~7 sec after the trigger. XRT and UVOT observations will begin when the source comes out of Earth constraint near T+21 minutes. Burst Advocate for this burst is T. N. Ukwatta (tilan.ukwatta AT gmail.com). 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: 7895 SUBJECT: GRB 080623: Swift XRT prompt analysis DATE: 08/06/23 11:13:13 GMT FROM: Phil Evans at U of Leicester D. Perez (U. Leicester-U. Jaen), K. Page, P. Evans, A. Beardmore (U. Leicester) report on behalf of the Swift XRT Team The XRT began observing the field at 10:47:31.4 UT, 22.0 minutes after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source located at RA, Dec 237.66083, -62.04897 which is equivalent to: RA(J2000) = 15h 50m 38.60s Dec(J2000) = -62d 02' 56.3" with an uncertainty of 3.0 arcseconds (radius, 90% containment). This location is 39 arcseconds from the BAT onboard position, within the BAT error circle. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 2.59e+21 cm^-2 (Kalberla et al. 2005). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7896 SUBJECT: GRB 080623: Swift/UVOT Non-Detection of an Optical Afterglow DATE: 08/06/23 11:35:42 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC S. T. Holland (CRESST/USRA/GSFC) reports on behalf of the Swift/UVOT Team: UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 1331 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle (Perez, et al., 2008, GCN Circ. 7895). The 3-sigma upper limit is 21.1 mag. No correction has been made for the large expected extinction corresponding to E(B-V) of 0.35 mag. The USNO B1.0 star 279-072176 is located 2.07 arcsec from the centre of the XRT error circle. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7897 SUBJECT: GRB 080623: TAROT La Silla observatory optical observations DATE: 08/06/23 12:26:04 GMT FROM: Alain Klotz at CESR-CNRS Klotz, A. (CESR-OMP), Boer M. (OHP), Atteia J.L. (LATT-OMP) report: We imaged the field of GRB 080623 detected by SWIFT (trigger 315080) with the TAROT robotic telescope (D=25cm) located at the European Southern Observatory, La Silla observatory, Chile. The observations started 425.1s after the GRB trigger (14.8s after the notice). The elevation of the field decreased from 12 degrees above horizon and weather conditions were good but only four images of 90s were taken due to the end of the night. The date of trigger : t0 = 2008-06-23T10:25:28.44 We do not detect any optical transient at the XRT position (Ukwatta et al. GCNC 7894) with the following limiting magnitudes: The first image is 90.0s exposure: t0+425s to t0+515s : R > 16.2 We co-added the four exposures: t0+425s to t0+802.0s : R > 17.0 This last value is conservative because the star density is high and the spatial sampling of TAROT (i.e. 3.3 arcsec/pix) is not adapted to separate close sources fainter than mag 17.0 at the XRT position. Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction. N.B. Galactic coordinates are lon=322.3398 lat= -6.1221 and the galactic extinction in R band is 0.94 magnitudes estimated from D. Schlegel et al. 1998ApJ...500..525S. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7898 SUBJECT: GRB 080623: Enhanced Swift-XRT position DATE: 08/06/23 16:00:38 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 199 s of overlapping XRT Photon Counting mode and UVOT data for GRB 080623, 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 = 237.66166, -62.04919 which is equivalent to: RA (J2000): 15h 50m 38.80s Dec (J2000): -62d 02' 57.1" 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), 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: 7899 SUBJECT: GRB 080623, Swift-BAT refined analysis DATE: 08/06/23 17:35:06 GMT FROM: Scott Barthelmy at NASA/GSFC W. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), K. McLean (GSFC/UMD), D. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC), T. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+1390 sec from recent telemetry downlinks, we report further analysis of BAT GRB 080623 (trigger #315080) (Ukwatta, et al., GCN Circ. 7894). The BAT ground-calculated position is RA, Dec = 237.667, -62.044 deg which is RA(J2000) = 15h 50m 40.1s Dec(J2000) = -62d 02' 36.7" with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 33%. The mask-weighted light curve shows four overlapping peaks starting at ~T-1 sec and ending at ~T+18 sec. T90 (15-350 keV) is 15.2 +- 5 sec (estimated error including systematics). The time-averaged spectrum from T-0.7 to T+16.0 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.35 +- 0.15. The fluence in the 15-150 keV band is 1.0 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+7.23 sec in the 15-150 keV band is 2.0 +- 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/315080/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7900 SUBJECT: GRB 080623: Swift-XRT refined analysis DATE: 08/06/23 20:06:49 GMT FROM: Dolores Perez-Ramirez at U.Leicester D. Perez (U. Leicester-U. Jaen), K.L. Page (U. Leicester), T. N. Ukwatta (GSFC/GWU), report on behalf of the Swift-XRT team: We have analysed the first three orbits of data obtained for GRB 080623 (Ukwatta et al., GCN Circ. 7894), covering 4.3ks of Photon Counting (PC) mode data. The UVOT-enhanced XRT position was given by Beardmore et al. in GCN Circ. 7898. The light-curve can be fitted with a single powerlaw with a decay of alpha ~1.0 +/- 0.1. The first three orbits of PC data can be modelled with an absorbed powerlaw, with Gamma = 2.03 +/- 0.14 and total NH = (0.37 +/- 0.05)x10^22 cm^-2, in excess of the Galactic value of 0.26x10^22 cm^-2. The observed (unabsorbed) flux over this time interval is 8.05 x10^-12 (1.34x10^-11) erg cm^-2 s^-1. The counts to observed flux conversion is 5.3x10^-11 erg cm^-2 count^-1. If the light-curve continues to decay at alpha ~ 1.0, the count rate at 24 hours is predicted to be 0.0086 count s^-1, corresponding to an observed flux of 4.5x10^-13 erg cm^-2 s^-1. This is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7901 SUBJECT: GRB080623: Swift UVOT followup observations DATE: 08/06/23 20:43:04 GMT FROM: Alice Breeveld at MSSL-UCL A. A. Breeveld (MSSL/UCL) and T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift/UVOT team. The Swift Ultra-Violet/Optical Telescope (UVOT) began settled observations of GRB 080623 (Ukwatta et al., GCN Circ. 7894) 22.15 minutes after the trigger, as reported in Holland, GCN Circ. 7896. We confirm that no afterglow is detected at the position of the enhanced XRT position (Beardmore et al., GCN Circ. 7898) in the initial finding chart or subsequent summed images. The following table gives the 3 sigma upper limits in all filters. Filter T_start(s) T_stop(s) Exp(s) Mag UL (3sig) white 1329 1428 98.1 >20.4 white 1559 2713 76.9 >20.3 white 8133 8332 196.6 >20.8 v 1436 2598 155.6 >19.0 b 1535 2698 155.5 >19.9 u 1510 2673 155.4 >19.7 uvw1 1486 2648 155.5 >19.4 uvm2 1460 2623 155.6 >19.1 uvw2 1575 2573 136.1 >19.3 The values quoted above are in the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627). No correction has been made for the large expected extinction corresponding to E(B-V) of 0.35 mag in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7902 SUBJECT: GRB 080623: GROND upper limits DATE: 08/06/25 02:42:32 GMT FROM: Adria C. Updike at Clemson U A. Updike (Clemson Univ.), S. Loew, J. Greiner, T. Kruehler, A. Kuepcue Yoldas, A. Yoldas, (all MPE Garching), G. Szokoly (Eoetvoes Univ., Budapest and MPE Garching), report for the GROND team: We observed the field of GRB 080623 detected by Swift/BAT (Ukwatta et al. 2008, GCN 7894) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405), mounted at the 2.2m MPI/ESO telescope at La Silla (Chile). A first epoch started on Jun. 23 at 22:50 UT (12.3 hrs after the GRB) and continued for 2.5 hours; the second epoch was obtained on Jun. 24 at 23:50 UT (mid-time). We do not detect any new source within the astrometrically corrected XRT position (Beardmore et al. 2008, GCN 7898). We note that there is a bright star at the border of the XRT error circle and a fainter one just outside the XRT error circle. A finding chart can be found at http://www.mpe.mpg.de/~jcg/grb080623.html . Both objects are visible in DSS2-R and are constant between our two epochs. Image subtraction revealed no hidden sources. Limiting magnitudes inside the XRT error circle are g'>24.3, r'>23.5, i'>21.8, z'>21.7, J>20.2, H>19.4, K>17.5, calibrated against USNO-B1 and 2MASS stars. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7909 SUBJECT: GRB 080623: Suzaku WAM observation of the prompt emission DATE: 08/06/28 02:39:45 GMT FROM: Yoshitaka Hanabata at Hiroshima U Y. Terada, M. Tashiro, Y. Urata, K. Onda, A. Endo, N. Kodaka, K. Morigami, T. Sugasahara, W. Iwakiri (Saitama U.), M. Ohno, M. Kokubun, M. Suzuki, T. Takahashi (ISAS/JAXA), Y. Fukazawa, T. Takahashi, T. Uehara, C. Kira, Y. Hanabata (Hiroshima U.), K. Yamaoka, S. Sugita (Aoyama Gakuin U.), Y. E. Nakagawa, T. Tamagawa (RIKEN), T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo), E. Sonoda, M. Yamauchi, H. Tanaka, R. Hara (Univ. of Miyazaki), S. Hong (Nihon U.), on behalf of the Suzaku WAM team, report: The long GRB 080623 (Swift/BAT trigger #315080 ; Ukwatta et al., GCN 7894) was detected by the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 10:25:28 UT on 23 July 2008 (=T0). The observed light curve shows a multi-peaked structure starting at T0, ending at T0+10 s with a duration (T90) of about 7 seconds. The fluence in 100 - 1000 keV was (1.6 +/- 0.4) E-6 erg/cm^2. The 1-s peak flux measured from T0+ 8 s was 0.5 +/- 0.4 photons/cm^2/s in the same energy range. Preliminary result shows that the time-averaged spectrum from T0 to T0+10 s is well fitted by a single power-law with a photon index of 2.0 -0.9+1.0 (chi^2/d.o.f = 5.6 / 8) at the 150 - 600 keV bandpass. ---- All the quoted errors are at statistical 90% confidence level, in which the systematic uncertainties are not included. ---- The light curves with 1-sec time resolution for this burst will be appeared at the following URL. http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/untrig/grb_table.html [GCN OPS NOTE(30jun08): Per author's request, the Subject was changed from "080523" to "080623".]