//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7203 SUBJECT: GRB 080123: Swift detection of a short burst DATE: 08/01/23 04:43:57 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT T. N. Ukwatta (GSFC/GWU), W. H. Baumgartner (GSFC/UMBC), M. M. Chester (PSU), N. Gehrels (NASA/GSFC), S. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU), S. Immler (CRESST/GSFC/UMD), J. A. Kennea (PSU), V. Mangano (INAF-IASFPA), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), T. Sakamoto (NASA/UMBC), B. Sbarufatti (INAF-IASFPA) and D. E. Vanden Berk (PSU) report on behalf of the Swift Team: At 04:21:57 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 080123 (trigger=301578). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 338.929, -64.890 which is RA(J2000) = 22h 35m 43s Dec(J2000) = -64d 53' 23" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a double-peaked structure with a duration of about 0.5 sec. The peak count rate was ~6000 counts/sec (15-350 keV), at ~0.1 sec after the trigger. The XRT began observing the field at 04:23:38 UT, 102 seconds after the BAT trigger. Using prompt downlinked data, we find a bright, fading X-ray source located at RA, Dec 338.9446, -64.9011 which is RA(J2000) = 22h 35m 46.71s Dec(J2000) = -64d 54' 04.0" with an uncertainty of 1.6 arcsec (radius, 90% containment). This location is 46 arcseconds from the BAT on-board position, outside the BAT error circle. UVOT took a finding chart exposure of nominal 100 seconds with the White (160-650 nm) filter starting 111 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. Image catalog data are not available at this time. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.03. 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: 7204 SUBJECT: GRB 080123: Enhanced Swift-XRT position DATE: 08/01/23 10:46:03 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 390 s of overlapping XRT Photon Counting mode and UVOT V-band data for GRB 080123, 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 = 338.94226, -64.90090 which is equivalent to: RA (J2000): 22h 35m 46.1s Dec (J2000): -64d 54' 3.24" with an uncertainty of 2.1 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, astro-ph/0708.0986 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: 7205 SUBJECT: GRB 080123, Swift-BAT refined analysis DATE: 08/01/23 14:54:48 GMT FROM: Scott Barthelmy at NASA/GSFC J. Tueller (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (GSFC/ISAS), M. Stamatikos (GSFC/ORAU), T. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-240 to T+962 sec from recent telemetry downlinks, we report further analysis of BAT GRB 080123 (trigger #301578) (Ukwatta, et al., GCN Circ. 7203). The BAT ground-calculated position is RA, Dec = 338.974, -64.930 deg which is RA(J2000) = 22h 35m 53.8s Dec(J2000) = -64d 55' 48" with an uncertainty of 4.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 20%. The mask-weighted light curve shows two well-separated peaks. The first starts at ~T+0.3 sec and is no wider than 64 msec. The second peak starts at ~T+0.6 sec with a FRED-like shape and a duration of ~256 msec. There is soft extended emission lasting ~120 sec. T90 (15-350 keV) is 115 +- 30 sec (estimated error including systematics). The time-averaged spectrum from T+0.3 to T+122.2 sec (SHB plus extended emmission) is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.15 +- 0.54. The fluence in the 15-150 keV band is 5.7 +- 1.7 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T-0.05 sec in the 15-150 keV band is 1.8 +- 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/301578/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7207 SUBJECT: GRB 080123: Swift/UVOT refined analysis DATE: 08/01/23 16:09:43 GMT FROM: Antonino Cucchiara at PSU A. Cucchiara (PSU), T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift-UVOT team: The Swift/UVOT observed the field of GRB080123 (trigger #301578) starting 111 seconds after the BAT trigger (Ukwatta et al. 2008, GCN Circ. 7203). We do not find any new source in any of the UVOT single or coadded observations inside the XRT enhanced error circle (Osborne et al., GCN Circ. 7204). The XRT position is not covered by the V ,U and B images. The 3-sigma upper limits (in the UVOT photometric system, Breeveld et al., GCN Circ. 6614) are listed: Filter Tstart Tstop Exp Magnitude (s) (s) (s) white 112 211 100 >20.48 (finding chart) uvw1 651 8022 577 >20.86 uvm2 626 7817 578 >20.70 uvw2 731 14026 1188 >21.56 The values quoted above are not corrected for the expected Galactic extinction corresponding to a reddening of E_{B-V} = 0.03 mag in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7208 SUBJECT: GRB 080123: Swift-XRT refined analysis DATE: 08/01/23 17:24:42 GMT FROM: Boris Sbarufatti at INAF-IASF-Pa V. Mangano, B. Sbarufatti (INAF-IASF PA), T. N. Ukwatta (GSFC/GWU), and D. N. Burrows (PSU) report on behalf of the Swift XRT team: We have analyzed the XRT data collected during the first three orbits of observation of GRB 080123 (Ukwatta et al., GCN Circ. 7203). We have 124 s of exposure in WT mode (from T+108 to T+224 s) and 7.1 ks in PC mode. The initial XRT on-board position was centered on a cosmic ray hit. This position was retracted. The XRT position reported in GCN Circ. 7203 was obtained from the first downlinked data, but we note that the error circle given in this circular erroneously ignored the systematic component and was therefore much too small. The new, refined position of the XRT afterglow is 22h 35m 46.6s, -64d 54' 03.8" (J2000) with an error circle radius of 3.9" (90% confidence). As reported by Osborne et al. (GCN Circ. 7204), the UVOT-enhanced astrometric position is RA, Dec = 338.94226, -64.90090 which is equivalent to: RA (J2000): 22h 35m 46.1s Dec (J2000): -64d 54' 03.24" with an uncertainty of 2.1 arcsec (radius, 90% confidence). The X-ray light curve of the source shows a doubly broken power law behaviour, with an initial decay with slope 1.7 +/- 0.2, a first break at T+203 +/- 10 s, a second decay phase with slope 6.9 +/- 0.4, a second break at T+436 +/- 250 s and a third decay phase with slope 1.2 +/- 0.3. If decaying at this rate the source will be at the level of 9.0e-5 counts/s at T+24 hr. The WT spectrum is well fitted by an absorbed power law with photon index 1.64 +/- 0.09, while the PC spectrum can be fitted by a power law with photon index of 2.1 +/- 0.2. Both spectra are consistent with an absorption column of (8.1 +/- 2.4)e20 cm^-2, in excess with respect to the Galactic absorption along the line of sight (2e20 cm^-2, Kalberla et al. 2005). The observed (unabsorbed) flux in the 0.3-10 keV band is 7.0e-10 (7.9e-10) erg cm^-2 s^-1 for the WT spectrum and 1.1e-12 (1.4e-12) erg cm^-2 s^-1 for the PC spectrum. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7223 SUBJECT: GRB 080123 : Suzaku WAM observation of the prompt emission DATE: 08/01/28 13:12:19 GMT FROM: Takeshi Uehara at Hiroshima U T. Uehara, M. Ohno, T. Takahashi, Y. Fukazawa, C. Kira, Y. Hanabata (Hiroshima U.), T. Tamagawa (RIKEN), K. Yamaoka, Y. E. Nakagawa, S. Sugita (Aoyama Gakuin U.), M. Tashiro, Y. Terada, Y. Urata, A. Endo, K. Onda, M. Suzuki, N. Kodaka, K. Morigami (Saitama U.), T. Enoto, R. Miyawaki, K. Nakazawa, K. Makishima (Univ. of Tokyo), E. Sonoda, M. Yamauchi, H. Tanaka, R. Hara (Univ. of Miyazaki), M. Kokubun, M. Suzuki, T. Takahashi (ISAS/JAXA), S. Hong (Nihon U.), on behalf of the Suzaku WAM team, report: The short GRB 080123 (Swift/BAT trigger #301578 ; Ukwatta et al., GCN 7203) triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 2008-01-22 04:21:57 UT (=T0). The observed light curve shows a double-peaked structure starting at T0 s, ending at T0+0.4 s with a duration (T90) of about 0.40 seconds. The fluence in 100 - 1000 keV was 3.1 (+/- 0.5) x 10^-7 erg/cm^2. The 1-s peak flux measured from T0 s was 1.2 (+/- 0.2) photons/cm^2/s in the same energy range. Preliminary result shows that the time-averaged spectrum from T0 s to T0+0.5 s is well fitted by a single power-law with a photon index of 1.22 (+0.21, -0.52) (chi^2/d.o.f = 10/13). All the quoted errors are at statistical 90% confidence level, in which the systematic uncertainties are not included. 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: 7237 SUBJECT: GRB 080123: Early afterglow detection with BATSS (BAT Slew Survey) DATE: 08/01/29 23:57:04 GMT FROM: Antonio Copete at Harvard U A. Copete, J. Grindlay, B. Allen, J. Hong (Harvard) S. Barthelmy, C. Markwardt, N. Gehrels (GSFC) We report the independent detection of early afterglow (or post prompt- emission flaring) emission from the short GRB 080123 (GCN#7203). The BATSS pipeline processed the BAT data from the initial automatic slew to the burst, which started at 04:22:09 UT (T+12sec), and was completed within 5 hours of the BAT trigger. A 6.2-sigma image detection (from stacked 0.2sec slew images throughout the 68sec slew) in the 15-50 keV energy band yielded a position of: RA(J2000) = 22h 35m 08s Dec(J2000) = -64d 57' 24" with an uncertainty of 6 arcmin (90% confidence radius), consistent with the XRT reported position of GRB080123 (GCN# 7208). Preliminary lightcurve analysis shows the BATSS image detection is due to an inital ~4sec duration flare at T+20, followed by two possible broader (~10-15sec) peaks at T+49 and T+72. The total estimated fluence is 2.1E-7 erg/cm2 (15-50keV; derived for a PL model with photon index 2) over the 68.8sec duration of the slew. This fluence is a factor of 0.36 times that reported in the 15-150keV band (GCN Report 111.1) for T +0.3 to T+122.2 and is likely dominated by the soft flare emission after the prompt hard emission of the short GRB. BATSS pipeline processing is in the final stages of development following our first preliminary tests, which discovered GRB070326 (GCN# 6653). Full BATSS results will begin to be available soon from a website to be announced.