//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19645 SUBJECT: GRB 160703A: Swift detection of a burst DATE: 16/07/03 12:21:44 GMT FROM: David Palmer at LANL S. B. Cenko (GSFC), V. D'Elia (ASDC), N. Gehrels (NASA/GSFC), L. Izzo (IAA-CSIC), J. A. Kennea (PSU), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), T. Sakamoto (AGU), B. Sbarufatti (INAF-OAB/PSU) and T. N. Ukwatta (LANL) report on behalf of the Swift Team: At 12:10:05 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 160703A (trigger=702699). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 287.392, +36.901 which is RA(J2000) = 19h 09m 34s Dec(J2000) = +36d 54' 04" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 60 sec. The peak count rate was ~10000 counts/sec (15-350 keV), at ~22 sec after the trigger. XRT is temporarily offline, and so there will be no immediate data from this GRB. UVOT took a finding chart exposure of 150 seconds with the White filter starting 75 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 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 0.14. Burst Advocate for this burst is S. B. Cenko (brad.cenko AT 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: 19647 SUBJECT: GRB 160703A: Zadko observatory - Gingin optical observations DATE: 16/07/03 19:25:36 GMT FROM: Alain Klotz at IRAP-CNRS-OMP Klotz A., Turpin D., Atteia J.L. (CNRS-OMP-IRAP), Boer, M., Laugier, R. (CNRS-ARTEMIS), Gendre B. (UVI - Etelman Obs.), Coward, D. McPherson, D. Williams A., Martin R., Moore J., Dodson R. (UWA) report: We imaged the field of GRB 160703A detected by SWIFT (trigger 702699) with the Zadko robotic telescope (D=100cm) located at the observatory - Gingin, Australia. The observations started 5.5h after the GRB trigger. The elevation of the field decreased from only 20 degrees above horizon and weather conditions were good. We co-added a series of exposures. No credible source was found in the BAT error box: t0+5.5h to t0+5.6h : Rlim = 19.4 Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19648 SUBJECT: GRB 160703A: Swift-BAT refined analysis DATE: 16/07/03 20:12:32 GMT FROM: Scott Barthelmy at NASA/GSFC A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), S. B. Cenko (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-240 to T+963 sec from the recent telemetry downlinks, we report further analysis of BAT GRB 160703A (trigger #702699) (Cenko, et al., GCN Circ. 19645). The BAT ground-calculated position is RA, Dec = 287.414, 36.913 deg, which is RA(J2000) = 19h 09m 39.4s Dec(J2000) = +36d 54' 46.2" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 84%. The mask-weighted light curve shows many overlapping peaks starting at ~T-26 sec, with the brightest peak at ~T+28 sec, and ending at ~T+75 sec. T90 (15-350 keV) is 44.4 +- 2.8 sec (estimated error including systematics). The time-averaged spectrum from T-26.43 to T+52.57 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.34 +- 0.04. The fluence in the 15-150 keV band is 9.0 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+26.64 sec in the 15-150 keV band is 5.8 +- 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/702699/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19649 SUBJECT: Konus-Wind observation of GRB 160703A DATE: 16/07/04 11:31:52 GMT FROM: Dmitry Frederiks at Ioffe Institute D. Frederiks, S. Golenetskii, R.Aptekar, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, A.Lysenko, A. Kozlova, and T. Cline, on behalf of the Konus-Wind team, report: The long GRB 160703A (Swift/BAT observation: Cenko et al., GCN 19645; Lien et al., GCN 19648) triggered Konus-Wind at T0=43807.015 s UT (12:10:07.015). The light curve shows multiple overlapping pulses, a total duration of the burst is ~50 s. The emission is seen up to ~4 MeV. As observed by Konus-Wind, the burst had a fluence of (2.7 ± 0.2)x10^-5 erg/cm2 and a 64-ms peak energy flux, measured from T0+23.360, of (2.8 ± 0.3)x10^-6 erg/cm2 (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum (measured from T0 to T0+41.216 s) is best fit in the 20 keV - 10 MeV range by a cutoff power-law (CPL) function with the following model parameters: the photon index alpha = -1.01(-0.09,+0.10), and the peak energy Ep = 327(-36,+46) keV, chi2 = 93/97 dof. Fitting this spectrum with the GRB (Band) function yields the same alpha and Ep with only an upper limit on beta of -2.4, chi2 = 93/96 dof. The spectrum near the peak count rate (measured from T0 to T0+41.216 s) is best fit in the 20 keV - 10 MeV range by a cutoff power-law (CPL) function with the following model parameters: the photon index alpha = -0.66(-0.15,+0.16), and the peak energy Ep = 272(-29,+35) keV, chi2 = 79/89 dof. Fitting this spectrum with the GRB (Band) function yields the same alpha and Ep with only an upper limit on beta of -3.1, chi2 = 79/88 dof. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB160703_T43807/ All the quoted errors are estimated at the 90% confidence level. All the presented results are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19650 SUBJECT: GRB 160703A: Bassano Bresciano Observatory upper limits DATE: 16/07/04 12:53:18 GMT FROM: Ulisse Quadri at Bassano Bresciano Obs U.Quadri, L.Strabla and R.Girelli report: We imaged the field of GRB 160703A detected by SWIFT(trigger 702699) with the robotic telescope of (IAU station 565) Bassano Bresciano Observatory, Italy. Member of: AAVSO - American Association of Variable Star Observers. ISSP - Italian Supernovae Search Project. UAI/SSV - Unione Astrofili Italiani/sezione stelle variabili. The observations started 8.31 hour after the GRB trigger, with our Schmidt telescope D=320/400 mm F/D=3.1. Weather conditions were good. We co-added a series of exposures of 120 sec each. Start T0+ End T0+ Vlim 8.31 hour 10.28 hour 19 We did not found any optical counterpart in the error box of the XRTcandidate. (S. B. Cenko (GSFC), V. D'Elia (ASDC), N. Gehrels (NASA/GSFC), et al.) Magnitudes were estimated with the UCAC4 cat. and are not corrected for galactic dust extinction. Reference: http://www.osservatoriobassano.org/GRB.asp The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19652 SUBJECT: GRB 160703A: MITSuME Akeno Optical Observations DATE: 16/07/04 17:56:53 GMT FROM: Taketoshi Yoshii at Tokyo Tech Y. Tachibana, Y. Saito, Y. Muraki, Y. Ono, T. Fujiwara, T. Yoshii, K. Saisho, H. Ohuchi, Y. Yano, S. Harita, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We report the optical follow-up observations of GRB 160703A (S. B. Cenko et al., GCN Circular #19645) with a tricolor camera (g', Rc, and Ic) attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan. The observation started at 2016-07-03 12:10:54 UT (~30 sec after the burst). Although the first eight frames (each exposure time is 30 sec) are covered by thick clouds, we detected a bright optical transient source in the refined BAT error circle (A. Y. Lien et al., GCN Circular #19648) ~5 min after the trigger. The position of the counterpart is RA(J2000) = 19h 09m 40.1s Dec(J2000) = +36d 55' 08.1" with an uncertainty of ~0.5 arc sec. Nearby the optical transient, a known source N2JN062852 (RA, Dec = 19h 09m 40.212s, +36d 55' 06.9816$B!I(B) catalogued in GSC2.3 is located. In the photometric analysis, we ignored the contamination from the nearby source because its flux is substantially lower (Fmag = 20.27) comparing with the optical counterpart. The results were shown below: T0+[min] MID-UT T-EXP[sec] g$B!G(B g$B!G(B_err Rc Rc_err Ic Ic_err ---------------------------------------------------------------------------------------------------------------------- 5.82 12:15:54 30 15.46 0.06 14.59 0.06 14.25 0.09 58.35 13:08:26 3900 18.18 0.05 17.08 0.04 16.87 0.06 330.52 15:40:36 7680 19.13 0.06 17.96 0.05 17.61 0.06 ---------------------------------------------------------------------------------------------------------------------- T0+ : Elapsed time after the burst T-EXP: Total Exposure time We used GSC2.3 catalog for flux calibration. Further analysis is ongoing. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19653 SUBJECT: GRB 160703A: MITSuME Ishigakijima Optical Observation DATE: 16/07/05 01:03:31 GMT FROM: Daisuke Kuroda at OAO/NAOJ D. Kuroda (OAO, NAOJ), H. Hanayama, T. Miyaji, J. Watanabe (IAO, NAOJ), K. Yanagisawa (OAO, NAOJ), S.Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of the MITSuME and OISTER collaboration: We observed the field of GRB 160703A (Cenko et al., GCNC 19645) with the optical three color (g', Rc and Ic) CCD camera attached to the Murikabushi 1m telescope of Ishigakijima Astronomical Observatory. The observation started on 2016-07-03 12:12:55 UT, (~2.8 min after the burst). We detected the previously reported afterglow (Tachibana et al., GCNC 19652) in in all the three bands. The photometric results of the OT are listed below. We used GSC2.3 catalog for flux calibration. #T0+[day] MID-UT T-EXP[sec] g' g'_e Rc Rc_e Ic Ic_e ------------------------------------------------------------------- 0.00232 12:13:25 60.0 14.02 0.02 13.73 0.02 13.35 0.01 0.13017 15:17:31 540.0 19.32 0.07 18.37 0.04 18.22 0.08 ------------------------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19655 SUBJECT: GRB 160703A: Swift-XRT afterglow detection DATE: 16/07/05 08:40:09 GMT FROM: Valerio D'Elia at ASDC V. D'Elia (INAF-OAR), L. Izzo (IAA-CSIC), D. Malesani (DARK/NBI), E. Troja (GSFC), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), T.G.R. Roegiers (PSU), B. Mingo (U. Leicester), A.P. Beardmore (U. Leicester), A. Maselli (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the Swift/BAT-detected burst GRB 160703A (Lien et al. GCN Circ. 19648), collecting 5.0 ks of Photon Counting (PC) mode data between T0+107.8 ks and T0+120.4 ks. An uncatalogued X-ray source is detected within the 3-sigma Swift/BAT error region and is above the RASS limit, and is therefore likely the GRB afterglow. The position of this source is RA, Dec=287.4168, +36.9175 which is equivalent to: RA (J2000): 19:09:40.04 Dec(J2000): +36:55:03.0 with an uncertainty of 3.9 arcsec (radius, 90% confidence). This position is 92 arcsec from the Swift/BAT position and 5.1 arcsec from the optical transient reported by Tachibana et al. (GCN Circ. 19652). The light curve is consistent with a constant source of mean count rate 1.7e-02 ct/sec. A power-law fit gives an index of 2.92 (+0.03, -3.89). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.9 (+0.7, -0.5). The best-fitting absorption column is 3.0 (+3.9, -1.5) x 10^21 cm^-2, consistent with the Galactic value of 1.5 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.9 x 10^-11 (5.4 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 3.0 (+3.9, -1.5) x 10^21 cm^-2 Galactic foreground: 1.5 x 10^21 cm^-2 Excess significance: <1.6 sigma Photon index: 1.9 (+0.7, -0.5) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00702699. The results of the full analysis of the XRT observations are available at http://www.swift.ac.uk/ToO_GRBs/00702699. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19656 SUBJECT: GRB 160703A: Swift/UVOT Detection DATE: 16/07/05 18:44:25 GMT FROM: Lea Hagen at PSU L. M. Z. Hagen (PSU) and S. B. Cenko (GSFC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 160703A 75 s after the BAT trigger (Cenko et al., GCN Circ. 19645). We detect a fading source consistent with the XRT position (D'Elia et al. GCN Circ. 19655) and optical detections (Tachibana et al., GCN Circ. 19652; Kuroda et al., GCN Circ. 19653). Preliminary detections using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 75 225 147 14.09+-0.02 white 567 1014 186 16.64+-0.03 white 4890 5090 196 18.33+-0.05 v 617 1064 58 16.51+-0.10 v 5300 5500 196 18.34+-0.17 b 543 735 38 16.38+-0.06 b 4685 4885 196 18.76+-0.11 u 288 537 245 15.05+-0.03 u 691 710 19 15.88+-0.09 u 4480 4680 196 17.79+-0.08 uvw1 666 1113 58 16.80+-0.12 uvm2 642 1089 58 17.75+-0.25 uvm2 5505 5695 187 19.07+-0.29 uvw2 593 1040 58 18.38+-0.27 uvw2 5096 5295 196 19.45+-0.30 The detection in all UVOT filters is consistent with a redshift of z < ~1.5. The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.15 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19668 SUBJECT: GRB 160703A: Keck-I/LRIS Optical Observations DATE: 16/07/09 04:19:22 GMT FROM: Weikang Zheng at UC Berkeley WeiKang Zheng, Alexei V. Filippenko (UC Berkeley), and Melissa Graham (University of Washington) report on behalf of the KAIT GRB team: We observed the field of GRB 160703A (Cenko et al., GCN 19645) with the 10 m Keck-I telescope on July 3 starting at 13:17:55 UT, or 1.125 hours after the burst. A 180 s g'-band image and a 150 s R-band image were taken simultaneously with LRIS. We detect the optical afterglow (Tachibana et al., GCN 19652; Kuroda et al., GCN 19653; Hagen & Cenko, GCN 19656) in both the g' and R images. The afterglow is well separated in our images from the nearby source N2JN062852 noted by Tachibana et al. (GCN 19652). We measure the afterglow to be 1.58" west and 1.30" north of N2JN062852. A finding chart is posted at website URL http://w.astro.berkeley.edu/~zwk/grb/GRB160703A/GRB160703A_keck_lris_g_fc.png . We find that the afterglow had a brightness of R=17.9 mag at 1.125 hours after the burst, calibrated with the USNO B1.0 R2 system. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19737 SUBJECT: GRB 160703A: 15 GHz upper limits from AMI DATE: 16/07/28 17:38:09 GMT FROM: Kunal Mooley at Oxford U K. P. Mooley, T. D. Staley, R. P. Fender (Oxford), G. E. Anderson (Curtin), T. Cantwell (Manchester), C. Rumsey, D. Titterington, S. H. Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge), K. Grainge, A. Scaife (Manchester) The AMI Large Array robotically triggered on the Swift alert for GRB 160703A (Cenko et al., GCN 19645) as part of the 4pisky program, and subsequent follow up observations were obtained up to 10 days post-burst. While the first observation on 2016 Jul 03.83 was severely affected by RFI, our observations at 15 GHz on 2016 Jul 04.99, Jul 07.00, and Jul 11.00 (UT) do not reveal any radio source at the XRT location (D'Elia et al., GCN 19655), with 3sigma upper limits of 150 uJy, 210 uJy, and 120 uJy respectively. We thank the AMI staff for scheduling these observations. The AMI-GRB database is a log of all GRB follow up observations with the AMI, and is available at http://4pisky.org/ami-grb/. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19739 SUBJECT: GRB160703A: Astrosat CZTI detection DATE: 16/07/29 04:23:54 GMT FROM: Varun Bhalerao at IUCAA V. Bhalerao (IUCAA), V. Kumar (IUCAA), D. Bhattacharya (IUCAA), A. R. Rao (TIFR), S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration: Analysis of Astrosat data showed the CZTI detection of a long duration GRB 160703A (Swift/BAT observation:Cenko et al., GCN 19645, Swift/BAT triggered at 12:10:05 UT). The GRB occured at an angle of 134 degrees away from the CZTI pointing direction. The source was clearly detected in the 40-200 keV energy range. The light curve shows a complex structure, with a peak at UT 12:10:27.000. The peak count rate was 360.40 counts/sec above the background (four quadrants summed together), with a total of 5022.0 counts. The local mean background count rate was 352.0 counts/sec. Using cumulative rates, we measure a T90 of 45.0 secs. CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb . CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 19849 SUBJECT: Possible radio detection of GRB160703A with the GMRT DATE: 16/08/23 09:58:51 GMT FROM: Nayana A J at NCRA-TIFR A.J Nayana (NCRA-TIFR), Poonam Chandra (NCRA-TIFR), A. R. Rao (TIFR), Dipankar Bhattacharya (IUCAA) and Varun Bhalerao (IUCAA) report: We carried out Giant Metrewave Radio Telescope (GMRT) observations of GRB 160703A (Cenko et al. GCN Circ. 19645) at 1460 MHz band on 2016 Aug 11.79 UT. We detect a faint source at the GRB position (Cenko et al. GCN Circ. 19645) with a flux density of 166+/-46 uJy. This is most likely the radio afterglow of GRB 160703A. Map rms is 40 uJy. We thank GMRT staff for making these observations possible.