//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6678 SUBJECT: GRB 070729: Swift detection of a short hard burst DATE: 07/07/29 00:48:05 GMT FROM: Scott Barthelmy at NASA/GSFC C. Guidorzi (Univ Bicocca&INAF-OAB), L. M. Barbier (NASA/GSFC), S. D. Barthelmy (GSFC), N. Gehrels (NASA/GSFC), C. Gronwall (PSU), S. T. Holland (CRESST/GSFC/USRA), J. A. Kennea (PSU), V. Mangano (INAF-IASFPA), C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC), A. Moretti (INAF-OAB), D. M. Palmer (LANL), M. Stamatikos (NASA/ORAU) and T. N. Ukwatta (GSFC/GWU) report on behalf of the Swift Team: At 00:25:53 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 070729 (trigger=286373). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 56.322, -39.312 which is RA(J2000) = 03h 45m 17s Dec(J2000) = -39d 18' 41" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows three overlapping peaks with a total duration of about 1.5 sec. The peak count rate was ~2000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began taking data at 00:27:21 UT, 87 seconds after the BAT trigger. The XRT on-board centroid algorithm did not find a source in the image. Using prompt downlinked data, we find an uncatalogued X-ray source located at RA, Dec 56.3147, -39.3234 which is RA(J2000) = 03 45 15.52 Dec(J2000) = -39 19 24.2 with an uncertainty of 5.7 arcsec (radius, 90% containment). This location is 45 arcseconds from the BAT on-board position, within the BAT error circle. UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 91 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. The typical 3-sigma upper limit has been about 18.5 mag. No correction has been made for the expected Galactic extinction corresponding to a reddening of 0.02 mag. Burst Advocate for this burst is C. Guidorzi (cristiano.guidorzi AT brera.inaf.it). 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: 6680 SUBJECT: GRB 070729: Magellan NIR Observations DATE: 07/07/29 08:20:29 GMT FROM: Edo Berger at Carnegie Obs E. Berger (Carnegie Observatories) and D.L. Kaplan (MIT) report: "Starting on July 29.315 UT we observed the XRT position of the short burst GRB 070729 (GCN #6678) with Persson's Auxiliary Nasmyth Infrared Camera (PANIC) on the Magellan/Baade 6.5-m telescope. A total of 6 min were obtained in the Ks band in 0.55" seeing. We find a single, extended object within the XRT error circle with Ks ~ 18.2 mag, located at: RA = 03:45:15.52 DEC = -39:19:28.7 No point sources are visible within the XRT error circle to a 3-sigma depth of about 21.3 mag. Further observations are in progress." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6681 SUBJECT: GRB 070729, Swift-BAT refined analysis DATE: 07/07/29 13:18:29 GMT FROM: Scott Barthelmy at NASA/GSFC G. Sato (GSFC/ISAS), L. Barbier (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), C. Guidorzi (U.Bicocca&INAF-OAB), H. Krimm (GSFC/USRA), C. Markwardt (GSFC/UMD), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), 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+963 sec from recent telemetry downlinks, we report further analysis of BAT GRB 070729 (trigger #286373) (Guidorzi, et al., GCN Circ. 6678). The BAT ground-calculated position is RA, Dec = 56.296, -39.330 deg which is RA(J2000) = 3h 45m 11.1s Dec(J2000) = -39d 19' 47" with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 65%. The mask-weighted light curve shows two overlaping peaks starting at ~T-0.2 sec, peaking at ~T+0.2 and ~T+0.8 sec, and ending at ~T+1.2 sec. T90 (15-350 keV) is 0.9 +- 0.1 sec (estimated error including systematics). The time-averaged spectrum from T-0.1 to T+1.1 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 0.96 +- 0.27. The fluence in the 15-150 keV band is 1.0 +- 0.2 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.03 sec in the 15-150 keV band is 1.0 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6682 SUBJECT: GRB 070729: Swift-XRT refined analysis DATE: 07/07/29 14:43:33 GMT FROM: Cristiano Guidorzi at INAF-OAB C. Guidorzi, P. Romano (U.Bicocca & INAF-OAB), A. Moretti (INAF-OAB) report on behalf of the Swift-XRT team: we have analysed the first five orbits of Swift-XRT data obtained for GRB 070729 (Guidorzi et al., GCN Circ. 6678), which include 9.1 ks of Photon Counting (PC) data. We find a refined X-ray position of RA, Dec (J2000) = 56.31385, -39.32400 which is equivalent to: RA (J2000): 03 45 15.32 Dec (J2000): -39 19 26.4 with an uncertainty of 4.5 arcsec (radius, 90% confidence). This is 3.2 arcsec from the initial XRT position (GCN Circ. 6678) and 53 arcsec from the BAT ground-calculated position (Sato et al., GCN Circ. 6681). The XRT light-curve of the first orbit, in the time interval from T+95s to T+600s, shows a fading behaviour with a power-law index of 1.5+/-0.6. The upper limit on the count rate derived from the data of the following orbits is consistent with it. The spectrum (35 photons) can be fit using Cash statistics with an absorbed power law with a photon index of 1.8+/-0.4 and a column density consistent with the Galactic value (2.6e20 cm^-2; Kalberla et al. 2005). The absorbed (unabsorbed) 0.3-10.0keV flux for the spectrum is (2.2+/-0.7)e-13 ((2.4+/-0.7)e-13) ergs cm^-2 s^-1, at mean time of T+0.13d. If the decay continues with a slope of ~ 1.5, the count rate at 24 hours is predicted to be 1e-5 count s^-1; this ranges between 4e-4 and 3e-7 count s^-1, taking into account the uncertainties on the slope. Using the spectral fit detailed above, this corresponds to an observed flux <2e-14 erg cm^-2 s^-1 (over 0.3-10 keV). This circular is an official product of the XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6683 SUBJECT: GRB070729: Swift/UVOT upper limits DATE: 07/07/29 16:17:07 GMT FROM: Antonino Cucchiara at PSU A. Cucchiara (PSU), C. Guidorzi (U.Bicocca & INAF-OAB) report on behalf of the Swift-UVOT team: The Swift/UVOT observed the field of GRB070729 (trigger=286373) starting 2007-0729 at 00:27:24, 91 s after the BAT trigger (Guidorzi et al. 2007, GCN Circ. 6678). We do not find any new source in any of the UVOT observations inside the refined XRT error circle (Guidorzi 2007, GCN Circ. 6782). The 3-sigma upper limits (in the UVOT photometric system, Breeveld et al., GCN Circ. 6614)for detecting a source inside the XRT error circle in the first finding chart (FC) exposure and the co-added frames (including the finding chart) are listed below: Filter Tstart Tstop Exposure Magnitude (s) (s) (s) (3-sigma UL) White FC 91 191 99.7 20.27 White 91 6079 491 21.30 v 200 33740 1767 20.45 b 4241 19519 1163 20.97 u 4036 25507 2828 21.12 uvw1 3831 24911 3049 21.53 uvm2 606 27229 2764 21.34 uvw2 4652 28966 2164 21.46 The values quoted above are not corrected for the expected Galactic extinction corresponding to a reddening of E_{B-V} = 0.02 mag in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6686 SUBJECT: GRB 070729: LCO optical imaging DATE: 07/07/29 22:45:51 GMT FROM: Edo Berger at Carnegie Obs E. Berger, D. Murphy (Carnegie Observatories) report: "We imaged the position of the X-ray afterglow of GRB 070729 (GCNs #6681,6682) with the Swope 40-inch telescope at Las Campanas Observatory starting on 2007 July 29.385 UT. A total of 3600 sec were obtained in R-band. We do not detect any sources within the XRT error circle, including the possible host galaxy detected in K-band with Magellan (GCN #6680). The 3-sigma limit is R>21.8 mag, indicating that the putative host is red, with R-K>3.6 mag." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6690 SUBJECT: Konus-A observation of GRB 070729 DATE: 07/07/31 12:33:00 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P. Oleynik and M. Ulanov on behalf of the Konus-A team report: The short hard GRB 070729 (Swift-BAT trigger #286373: Guidorzi et al., GCN 6678; Sato et al., GCN 6681), triggered Konus-A (Cosmos-2421) at T0=1554.9 s UT (00:25:54.9). As observed by Konus-A the burst had a fluence of 5.59(-4.38, +0.05)x10^-7 erg/cm2, and a 64-ms peak flux measured from T0-0.840 s of 1.07(-0.92, +0.38)x10^-6 erg/cm2/s (both in the 20 keV - 1 MeV energy range). Preliminary analysis shows that the time-integrated spectrum of the burst (from T0-1 s to T0) can be fitted (in the 20 keV - 1 MeV range) by a power law with exponential cutoff model: dN/dE ~ E^(-alpha)*exp(-E*(2-alpha)/Ep) with alpha = 1.08 (-0.36, +0.28) and Ep = 467(-195, +848) keV (chi2 = 36/48 dof). All the quoted errors are at the 90% confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6742 SUBJECT: VLA upper limit on the short hard burst GRB 070729 DATE: 07/08/10 15:17:06 GMT FROM: Poonam Chandra at U Virginia/NRAO Poonam Chandra (NRAO/UVA) and Dale A. Frail (NRAO) report on behalf of the Caltech-NRAO-Carnegie GRB Collaboration: "We used the Very Large Array to observe the field of view towards short hard burst GRB 070729 (GCN 6678) at a frequency of 8.46 GHz on 2007 August 7th at 12.15 UT for 30 minutes. The GRB is undetected and the peak radio brightness at the SWIFT-XRT position (GCN 6682) is -71 uJy ± 85 uJy. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc."