//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6594 SUBJECT: GRB 070704: Swift detection of a burst DATE: 07/07/04 20:40:31 GMT FROM: Scott Barthelmy at NASA/GSFC T. Sakamoto (NASA/ORAU), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), M. M. Chester (PSU), N. Gehrels (NASA/GSFC), O. Godet (U Leicester), S. T. Holland (CRESST/GSFC/USRA), S. Immler (GSFC/UMCP), F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester), D. M. Palmer (LANL), G. Sato (GSFC/ISAS), B. Sbarufatti (INAF-IASFPA) and R. L. C. Starling (U Leicester) report on behalf of the Swift Team: At 20:05:57 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 070704 (trigger=283791). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 354.723, +66.248 which is RA(J2000) = 23h 38m 54s Dec(J2000) = +66d 14' 52" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve does not show anything significant, as is typical for image-trigger events. There is a possibility that the burst started at ~T-70 sec, but since Swift was executing a preplanned slew from ~T-35 to T_0 sec, it is difficult to interpret the TDRSS lightcurve. The XRT began observing the field at 20:08:30 UT, 153 seconds after the BAT trigger. The on-board XRT position was not correct, because the algorithm centroided on a hot pixel. From the ground data analysis, a moderately bright and uncatalogued X-ray source was found at RA, Dec 354.69922, + 66.25226 which is RA(J2000) = 23h 38m 47.8s Dec(J2000) = 66d 15' 08.1" with an uncertainty of 5.5 arcseconds (radius, 90% containment). This location is 40.8 arcseconds from the BAT on-board position, outside the BAT error circle. The initial flux in the 2.5s image was 3.7e-10 erg/cm2/s (0.2-10 keV). UVOT took a finding chart exposure of 100 seconds with the White (160-650 nm) filter starting 158 seconds after the BAT trigger, and a finding chart exposure of 400 seconds with the V filter starting 265 seconds after the BAT trigger. No afterglow candidate has been found in the initial data products. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT and XRT error circles. The 2.7'x2.7' sub-image does not cover the XRT error circle. The list of sources is typically complete to about 18.0 mag. No correction has been made for the large, but uncertain extinction expected. Burst Advocate for this burst is T. Sakamoto (takanori 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: 6596 SUBJECT: GRB 070704, Swift-BAT refined analysis DATE: 07/07/04 23:50:57 GMT FROM: Scott Barthelmy at NASA/GSFC C. Markwardt (GSFC/UMD), L. Barbier (GSFC), S. D. Barthelmy (GSFC), J. Cummings (GSFC/UMBC), E. Fenimore (LANL), N. Gehrels (GSFC), H. Krimm (GSFC/USRA), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/ORAU), G. Sato (GSFC/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+523 sec from the recent telemetry downlink, we report further analysis of BAT GRB 070704 (trigger #283791) (Sakamoto, et al., GCN Circ. 6594). The BAT ground-calculated position is RA, Dec = 354.707, 66.257 deg which is RA(J2000) = 23h 38m 49.6s Dec(J2000) = 66d 15' 25" with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment). The partial coding was 42%. The mask-weighted light curve shows the burst started at ~T-65 sec when Swift was executing a preplanned slew. There are multiple peaks with decreasing amplitude with time. The burst almost returns to background during T+110 to T+230 sec, but then has emission from T+250 to T+410 sec. T90 (15-350 keV) is 380 +- 10 sec (estimated error including systematics). The time-averaged spectrum from T-57.3 to T+400.8 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.79 +- 0.08. The fluence in the 15-150 keV band is 5.9 +- 0.3 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T-53.10 sec in the 15-150 keV band is 2.1 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6597 SUBJECT: Swift/UVOT Observations of GRB070704 DATE: 07/07/05 10:16:46 GMT FROM: Patricia Schady at MSSL/Swift P. Schady (MSSL-UCL) and T. Sakamoto (NASA/ORAU) report on the behalf of the Swift UVOT team: The Swift/UVOT observed the field of GRB 070704 starting 142 s after the BAT trigger (Sakamoto et al. 2007, GCN Circ. 6594). We do not find any source, in any of the UVOT observations, inside the XRT error circle (Sakamoto et al. 2007, GCN Circ. 6594). The 3-sigma upper limits for detecting a source inside the refined XRT error circle in the initial data products are: Filter T_mid(s) Exp(s) Mag (3-sigma upper limit) ------------------------------------------------------- V 654 597 19.16 B 749 10 17.56 U 729 20 17.64 UVW1 5603 439 18.91 UVM2 4431 239 19.36 UVW2 5697 220 19.27 White 574 209 19.65 ----------------------------------------------------------------- where T_mid is the weighted mid time of the coadded exposure. The values quoted above are not corrected for the expected Galactic extinction corresponding to a reddening of E_{B-V} = 1.81 mag in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6598 SUBJECT: GRB 070704: Swift-XRT refined analysis DATE: 07/07/05 11:43:49 GMT FROM: Olivier Godet at U.of Leicester O. Godet (U. Leicester) & T. Sakamoto (GSFC/ISAS) report on behalf the Swift/XRT team We have analysed the first 8.5ks of Swift XRT PC and WT data of GRB 070704 (Sakamoto et al., GCN Circ. 6594) taken from T0+153s to T0+3e4s. Using 129 s of overlapping XRT Photon Counting mode and UVOT V-band data, 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 = 354.69915, +66.25328 which is equivalent to: RA (J2000): 23 38 47.80 Dec (J2000): +66 15 11.8 with an uncertainty of 2.7 arcsec (90% confidence). This is 3.7 arcsec from the initially reported XRT position and 39.4 arcsec from the BAT position (GCN Circ. 6594). The XRT light curve exhibits an initial decay on which is superposed a large flare peaking around T0+300s. We note that between T0+250s and T0 +410s an emission was also detected in the BAT (Markwardt et al., GCN Circ. 6596). The light-curve from T0+600s to T0+3e4s is fit well by a power-law with a decay index of 0.87 +0.11/-0.12. The spectrum of the WT data from T0+153s to T0+527s is fit well by an absorbed power-law with a photon index of 1.85 +/-0.06 and column density of N_H = (1.08+/-0.06)e22 cm^-2 in excess of the Galactic value (8.6E21 cm^-2; Dickey & Lockman, 1990). The absorbed (unabsorbed) 0.3-10.0keV flux for that spectrum is (1.57+/-0.05)E-9 (2.85E-9) ergs cm^-2 s^-1. The spectrum of the PC data from T0+530s to T0+3e4s is fit well by an absorbed power-law with a photon index of 1.97+/-0.27 with N_H fixed at 1.08e22 cm^-2. The absorbed (unabsorbed) 0.3-10.0keV flux for that spectrum is (3.3 +0.6/-0.8)E-12 (6.54E-12) ergs cm^-2 s^-1. Assuming the source continues to decay at the same rate, we predict an XRT count rate of 0.0044 counts/s at T0+24 hours, which corresponds to an observed (unabsorbed) flux of 6.2E-13 (2.9E-12) ergs cm^-2 s^-1. This circular is an official product of the Swift XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6602 SUBJECT: GRB 070704 : Liverpool Telescope Observations DATE: 07/07/06 12:50:15 GMT FROM: Andrea Melandri at Liverpool John Moores U A. Melandri (Liverpool JMU), E. Rol, N. Tanvir (U. Leicester) report on behalf of the RoboNet GRB collaborationon: We observed the field of GRB 070704 (trigger=283791, Sakamoto et al., GCN 6594) with the 2-m Liverpool Telescope about 4.2 hours after the trigger time. At the revised XRT position (Godet & Sakamoto, GCN 6598) we do not detect any new object in stacked images down to: Filter t_mid (hr from GRB) Tot_Exp (s) Lim -------------------------------------------------------------- r' 4.26 1800 23.0 i' 5.10 1800 23.3 -------------------------------------------------------------- Magnitudes were calibrated vs R2 and I USNO-B1 magnitude for few selected stars. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6603 SUBJECT: GRB070704: FAVOR optical observations DATE: 07/07/06 17:34:41 GMT FROM: Sergey Karpov at SAO RAS S. Karpov, G. Beskin (Special Astrophysical Observatory of Russian Academy of Sciences, Russia), S. Bondar, E. Ivanov, E. Katkova (Research Institute for Precision Instrumentation, Russia), A. Pozanenko (Space Research Institute, Russia) report on behalf of the FAVOR team: The field of GRB 070704 (Sakamoto et al, GCN 6594) has been observed by the FAVOR (FAst Variability Optical Registrator) wide-field fast camera (15 cm diameter, 16x21 deg FOV) located in Russia, North Caucasus, near 6-m telescope since UT 20:05:17 (40 seconds before BAT trigger, 25 seconds after actual burst onset), during the event and for 20 minutes after it with 7.5 frames per second acquisition rate (0.128 s frame exposure). The event occured on the edge of CCD detector and has been affected by the image distortion. The authomatic data reduction and transient detection pipeline, based on the inspection of each pixel statistical properties in time, has not detected any transient event at the XRT position of the source with the limiting magnitude of 10.8 (3-sigma) in the unfiltered light close to V on a single frame. We performed additional study of the data on T-40s - T+142s time interval (i.e. prior to Swift/UVOT observations). Combining the sets of 100 consecutive images we obtained an upper limit of 13.0 m (3-sigma) on the optical emission over this time span with temporal resolution of 12.8 s. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6616 SUBJECT: GRB 070704: Suzaku/WAM observation of the prompt emission DATE: 07/07/10 11:39:17 GMT FROM: Masanori Ohno at Hiroshima U C. Kira, M. Ohno, T. Uehara, T. Takahashi, Y. Fukazawa (Hiroshima U.), K. Yamaoka, Y. E. Nakagawa, S. Sugita (Aoyama Gakuin U.), K. Morigami, N. Kodaka, K. Onda, M. Tashiro, M. Suzuki,Y. Urata, A. Endo (Saitama U.), T. Enoto, R. Miyawaki, K. Nakawaza, K. Makishima (Univ. of Tokyo), S. Hong (Nihon U.), M. Kokubun, M. Suzuki, T. Takahashi (ISAS/JAXA), E. Sonoda, M. Yamauchi, S. Maeno, H. Tanaka, R. Hara(Univ. of Miyazaki), T. Tamagawa, Y. Terada (RIKEN), and Suzaku WAM team report: The long burst, GRB 070704 (Swift/BAT trigger #283791; T. Sakamoto et al., GCN Circ. 6594; A. Melandri et al., GCN Circ. 6602; S. Karpov et al., GCN Circ.6603) was triggered at T0=2007-07-04 20:05:02 UT by Suzaku Wide-band All-sky Monitor (WAM) which covers the energy range of 50 keV - 5 MeV. The observed light curve shows the multiple peaked structures with a duration (T90 in the 50-5000 keV band) of nearly 35 seconds. According to the GCN Report 69.2, the light curve observed by Swift BAT shows an upsurge around T0+350, while in the light curve by Suzaku WAM, there is no such a structure. The fluence in the 100-1000 keV band was (8.4+/-1.7)*10^-6 erg/cm^2, and the 1-s peak flux in the same band was 0.19+/-0.06 photons/cm^2/s. Preliminary result shows that the time-averaged spectrum from T0-5 to T0+40 is well fitted by single power law with a photon index of 2.0+/-0.4 in 100-1000 keV range. All the quoted errors are at the 90% confidence level, while systematic errors are not included. The WAM light curve of this event is available at the following URL. http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6617 SUBJECT: GRB 070704: RTT150 optical observations DATE: 07/07/11 10:21:38 GMT FROM: Alexander Mescheryakov at IKI RAN A. Meshcheryakov, R. Burenin, M. Pavlinsky, R. Sunyaev (IKI), I. Khamitov, Z. Tunca (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.), I. Bikmaev, and N. Sakhibullin (KSU/AST) report: We observed the field of GRB 070704 (Sakamoto et al., GCN 6594) with Russian-Turkish 1.5-m telescope (RTT150, Bakyrlytepe,TUBITAK National Observatory, Turkey). The observations consisted of a series 30-second exposures in g',r',i' filters, until ~1h after the burst time we continue only r'-filter exposures. The first exposure in g' started at 20:15:13.9UT, i.e.556 s after the BAT trigger. The observations were finished ~1.5 hour after the burst time. In 30-second images as well as in combined images we do not detect any new object at the revised XRT position (Godet & Sakamoto, GCN 6598) down to following limiting magnitudes: Filter T_start(sec after trigger) Exp(s) Lim ---------------------------------------------------------------------------- g' 556 30 20.1 first 240 21.2 combined r' 641 30 20.1 first 1720 22.3 combined i' 721 30 20.3 first 180 21.3 combined This message may be cited. [GCN OPS NOTE(12jul07): Per author's request, IK was added to the author list, and the extra period after 'filter' in the 4th line was removed.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 6634 SUBJECT: Erratum : Suzaku WAM observation of GRB 070704 DATE: 07/07/17 10:08:01 GMT FROM: Masanori Ohno at Hiroshima U C. Kira, M. Ohno, T. Uehara, T. Takahashi, Y. Fukazawa (Hiroshima U.), K. Yamaoka, Y. E. Nakagawa, S. Sugita (Aoyama Gakuin U.), M. Tashiro, Y. Urata, A. Endo, K. Onda, M. Suzuki, N. Kodaka, K. Morigami (Saitama U.), T. Enoto, R. Miyawaki, K. Nakawaza, K. Makishima (Univ. of Tokyo), S. Hong (Nihon U.), M. Kokubun, M. Suzuki, T. Takahashi (ISAS/JAXA), E. Sonoda, M. Yamauchi, S. Maeno, H. Tanaka, R. Hara (Univ. of Miyazaki), T. Tamagawa, Y. Terada (RIKEN), and Suzaku WAM team report: The Suzaku WAM preliminary result of GRB 070704 (Kira et al. GCN Circ. 6616) contained a wrong value in a 1-s peak flux in the 100-1000 keV band. The correct value is 1.2 +/- 0.1 photons/cm^2/s. We apologize for this mistake.