//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7935 SUBJECT: GRB 080703A: ROTSE-III Detection of Optical Counterpart DATE: 08/07/03 19:06:08 GMT FROM: Eli Rykoff at UCSB E.S. Rykoff (UCSB), B. E. Schaefer (Louisiana State), report on behalf of the ROTSE collaboration: ROTSE-IIIa, located at Siding Spring Observatory, Australia, responded to GRB 080703A (Swift trigger 315819). The first image was at 19:00:45.1 UT, 31.5 s after the burst (11.1 s after the GCN notice time). The unfiltered images are calibrated relative to USNO A2.0. We detect a 14.7 magnitude, steady source with coordinates: 06:47:12.7 -63:13:08.6 (J2000), with positional uncertainty of 1" or better start UT mag mlim(of image) ---------------------------------- 19:00:45.1 14.7 15.9 This source is not visible in DSS (second epoch), 2MASS or the MPChecker database. A jpeg image is available at http://www.rotse.net/images/gsb315819_3a00_img.jpg Note that the object marked 18 is the candidate in question. Continuing observations are in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7936 SUBJECT: GRB 080703: Swift detection of a burst with optical afterglow DATE: 08/07/03 19:17:07 GMT FROM: David Palmer at LANL H. Ziaeepour (UCL-MSSL), S. D. Barthelmy (GSFC), M. M. Chester (PSU), J. R. Cummings (NASA/UMBC), P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), O. Godet (U Leicester), H. A. Krimm (CRESST/GSFC/USRA), C. B. Markwardt (CRESST/GSFC/UMD), F. E. Marshall (NASA/GSFC), P. T. O'Brien (U Leicester), C. Pagani (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL), D. Perez (U Leicester), P. Schady (MSSL-UCL), R. L. C. Starling (U Leicester), M. C. Stroh (PSU), T. N. Ukwatta (GSFC/GWU), D. E. Vanden Berk (PSU) and P. A. Ward (MSSL-UCL) report on behalf of the Swift Team: At 19:00:13 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 080703 (trigger=315819). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 101.867, -63.222 which is RA(J2000) = 06h 47m 28s Dec(J2000) = -63d 13' 19" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single peak with a duration of about 5 sec. The peak count rate was ~1500 counts/sec (15-350 keV), at ~0 sec after the trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source. The position, astrometrically enhanced by aligning promptly available UVOT field source positions to the USNO-B1 catalogue, is RA,Dec = 101.80538, -63.22039 (degrees) which is equivalent to: RA (J2000.0) = 06 47 13.29 DEC (J2000.0) = -63 13 13.4 with an uncertainty of 3.04 arcsec (radius, 90% containment). This position is 100.1 arcsec from the BAT position, inside the BAT error circle and 6.3 arcseconds from the UVOT position. UVOT took a finding chart exposure of nominal 100 seconds with the White (160-650 nm) filter starting 100 seconds after the BAT trigger. There is a candidate afterglow in the list of sources generated on-board at RA(J2000) = 06:47:12.65 = 101.8027 DEC(J2000) = -63:13:08.8 = -63.2191 with a 1-sigma error radius of about 0.8 arc sec. This position is 104.9 arc sec. from the center of the BAT error circle. The estimated magnitude is 17.6 with a 1-sigma error of about 0.5 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.07. 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: 7938 SUBJECT: GRB 080703, Swift-BAT refined analysis DATE: 08/07/03 23:21:52 GMT FROM: Scott Barthelmy at NASA/GSFC T. Sakamoto (GSFC/UMBC), S. D. Barthelmy (GSFC), W. Baumgartner (GSFC/UMBC), 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), G. Sato (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-120 to T+183 sec from the recent telemetry downlink, we report further analysis of BAT GRB 080703 (trigger #315819) (Ziaeepour, et al., GCN Circ. 7936). The BAT ground-calculated position is RA, Dec = 101.822, -63.211 deg, which is RA(J2000) = 06h 47m 17.2s Dec(J2000) = -63d 12' 40.7" with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 53%. The mask-weighted light curve shows a single peak starting at ~T-5 sec, peaking at ~T+0 sec, and ending at ~T+4 sec. T90 (15-350 keV) is 3.4 +- 0.8 sec (estimated error including systematics). The time-averaged spectrum from T-1.7 to T+2.1 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.53 +- 0.22. The fluence in the 15-150 keV band is 2.0 +- 0.3 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.04 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. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/315819/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7939 SUBJECT: GRB 080703: Enhanced Swift-XRT position DATE: 08/07/04 06:30:32 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 3392 s of overlapping XRT Photon Counting mode and UVOT data for GRB 080703, 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 = 101.80180, -63.21893 which is equivalent to: RA (J2000): 06h 47m 12.43s Dec (J2000): -63d 13' 08.2" with an uncertainty of 1.4 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: 7940 SUBJECT: GRB 080703: VLT observations of the afterglow DATE: 08/07/04 10:58:08 GMT FROM: Daniele Malesani at Niels Bohr Inst,Dark Cosmology Center D. Malesani, P. M. Vreeswijk, J. P. U. Fynbo, J. Hjorth (DARK/NBI), P. Jakobsson (Univ. Hertfordshire), report on behalf of a larger collaboration: We observed the field of GRB 080703 (Ziaeepour et al., GCN 7936) with the ESO VLT equipped with FORS1. Due to visibility constraints, observations could only be carried out during twilight at high airmass. The optical afterglow first reported by Rykoff & Schaefer (GCN 7935; see also Ziaeepour et al., GCN 7936) is detected in our image (15 s exposure). On 2008 Jul 3.948 UT (3.76 hr after the GRB), the afterglow had R ~ 21.6 assuming R = 15.92 for the USNO star at (06:47:12.61, -63:12:31.7). A finding chart is posted at http://www.astro.ku.dk/~malesani/GRB/080703/080703_finder.png No further observations are planned. We acknowledge excellent support from the ESO staff in executing this challenging observation, particularly Thomas Szeifert and Dominique Naef. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7941 SUBJECT: GRB 080703: UVOT Follow-Up Observation DATE: 08/07/04 11:15:48 GMT FROM: Paul Ward at MSSL P. Ward (MSSL-UCL) and H. Ziaeepour (UCL-MSSL) report on behalf of the Swift/UVOT team: The Swift Ultra-Violet/Optical Telescope (UVOT) started observing GRB 080703 (Rykoff et al. GCN 7935, Ziaeepour et. al, GCN 7936) ~100 seconds after the trigger. A quickly fading candidate afterglow is found in the UVOT White and V filters. The preliminary Swift/UVOT position of the optical afterglow candidate is: RA(J2000) = 06:47:12.639 = 101.8027 DEC(J2000) = -63:13:08.96 = -63.2192 with a 1-sigma error radius of about 0.5 arcsec. The following table gives the measured magnitudes: Filter T_start T_stop Exp Mag White 101 200 99.8 17.40 +/- 0.03 White 857 956 99.8 20.27 +/- 0.35 White 5905 6102 196.6 21.29 +/- 0.49 White 5905 19222 869.5 > 21.77 (1.9-sigma) V 207 606 399.8 18.02 +/- 0.10 V 963 1362 399.8 19.06 +/- 0.27 V 6315 6512 196.6 > 19.65 (0.2-sigma) V 6315 12021 1081.7 > 20.83 (0.9-sigma) B 687 1788 78.9 > 19.48 (1.8-sigma) B 663 1764 99.0 > 19.33 (1.5-sigma) UVW1 638 1885 99.9 > 19.55 (0.1-sigma) UVM2 613 1878 118.7 > 19.67 (1.7-sigma) UVW2 718 1829 79.1 > 19.55 (0.9-sigma) The values quoted above are in the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627). No correction has been made for the expected extinction corresponding to E(B-V) of 0.071 mag in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7942 SUBJECT: GRB 080703: Swift-XRT refined analysis DATE: 08/07/04 13:45:39 GMT FROM: Olivier Godet at U.of Leicester We analysed 12.1 ks of data in Photon Counting (PC) mode obtained for GRB 080703 (Ziaeepour et al., GCN Circ 7936) between 106 s and 3.1e4s after the trigger (T0). The UVOT-enhanced XRT position was given by Osborne et al. in GCN Circ. 7939. The X-ray light-curve shows an initial rise from T0+106s to ~T0+200s and then decays with a slope of ~1.2. From ~T0+700s to ~T0+2000s, the XRT light-curve shows some flaring activities. The light-curve after ~T0+1e4s decays with a slope of 1.57 +/-0.21. The hardness ratio does not show any significant spectral variation from T0+106s to T0+3.1e4s. The PC spectrum from T0+106s to T0+3.1e4s is well fitted by an absorbed power-law with a photon index of 1.7 +/-0.1 and an absorption column of (8.9 +3.9/-3.3)e20 cm**-2, in excess with respect to the Galactic one (5.2e20 cm**-2; Kalberla et al. 2005). The observed 0.3-10 keV flux over this time interval is (8.2 +0.8/-1.2)e-12 erg/cm**2/s. If the light-curve continues to decay with alpha = 1.6, the count rate at 24 hours after the trigger is estimated to be 7e-3 counts/s, which corresponds to an observed flux of 6.7e-13 erg/cm**2/s. This is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 7944 SUBJECT: GRB 080703: GROND Upper Limits DATE: 08/07/04 18:25:08 GMT FROM: Christian Clemens at MPE C. Clemens, S. Loew, J. Greiner, A. Yoldas, T. Kruehler (all MPE Garching), A. Kupcu Yoldas (ESO) and G. Szokoly (Eoetvoes Univ., Budapest) report on behalf of the GROND team: We observed the field of GRB 080703 (Swift trigger 315819; Ziaeepour et al., GCN #7936) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m ESO/MPI telescope at La Silla Observatory (Chile). Observations started at 23:04 UT on July 3rd, 2008, 4.1 hrs after the GRB trigger with 4.7 min of effective exposures in g'r'i'z' and 8.0 min in JHK, and were performed at an average seeing of 1.8" during astronomical twilight. We do not detect any object within the 0.5'' Swift-UVOT error circle reported by Ward & Ziaeepour (GCN #7941) to the following upper limits: g' > 22.1 mag, r' > 22.6 mag, i' > 21.8 mag, z' > 21.3 mag, J > 19.3 mag, H > 18.1 mag and K > 17.0 mag. These upper limits are calibrated against USNO-B1 as well as 2MASS field stars.