//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13487 SUBJECT: IPN Triangulation of unusual GRB 120716A DATE: 12/07/17 20:16:23 GMT FROM: Dmitry Svinkin at Ioffe Institute K. Hurley, and J. Goldsten, on behalf of the MESSENGER GRNS GRB team, S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, V. Connaughton, M. Briggs, and C. Meegan, on behalf of the Fermi GBM team, A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, and K. Yamaoka, M. Ohno, Y. Hanabata, Y. Fukazawa, T. Takahashi, M. Tashiro, Y. Terada, T. Murakami, and K. Makishima on behalf of the Suzaku WAM team, report: The long-duration GRB 120716A has been observed by Fermi (GBM: trigger 364151106), Konus-Wind, INTEGRAL (SPI-ACS), Suzaku (WAM), and MESSENGER (GRNS), so far, at about 61504 s UT (17:05:04). The burst light curve shows a short initial pulse followed in ~170 s period of quiescence by two long pulses with a total duration of ~60 s. We have triangulated both emission episodes and have revealed that they came from the same direction. We have localized the burst to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 313.089 (20h 52m 21s) +9.558 ( +9d 33' 28") Corners: 311.595 (20h 46m 23s) +9.913 ( +9d 54' 46") 313.791 (20h 55m 10s) +10.049 (+10d 02' 56") 314.615 (20h 58m 28s) +9.110 ( +9d 06' 36") 312.407 (20h 49m 38s) +9.046 ( +9d 02' 45") --------------------------------------------- The error box area is 2.04 sq. deg, and its maximum dimension is 3.1 deg. This box can be improved. A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB120716_T61507/IPN/ The time history and spectrum will be given in a forthcoming GCN Circular. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13488 SUBJECT: Konus-Wind observation of GRB 120716A DATE: 12/07/18 10:21:17 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report: The long-duration unusual GRB 120716A (IPN detection and localization: Hurley at al., GCN 13487) triggered Konus-Wind at T0=61507.357s UT (17:05:07.357) The light curve started with a short (~0.9 s) pulse followed, after ~170 s, by a double-peaked structure lasting for ~60 s. The total duration of the burst is ~230 s. This GRB is similar to GRB 041219A, GRB 050820A, and GRB 060124, which display a rather short precursor, a ~200 s long period of quiescence, and the main episode of emission. For this burst, the precursor is relatively short and bright and the main part is shorter and dimmer. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB120716_T61507/ As observed by Konus-Wind: - the precursor had a fluence of 1.4(-0.3,+1.0)x10-6 erg/cm2, and a 64-ms peak flux, measured from T0-0.064 s, of 3.3(-0.8,+2.7)x10-6 erg/cm2/s; - the main part of the burst had a fluence of 1.3(-0.3,+0.3)x10-5 erg/cm2, and a 256-ms peak flux, measured from T0+181.760 s, of 8.8(-0.15,+0.15)x10-7 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The 3-channel spectrum of the precursor (from T0-0.256 to T0+0.512 s) can be modeled (in the 20-1200 keV range) by a power law with exponential cutoff model with alpha = -1.3 ± 0.1 and Ep = 380 ± 50 keV (one-sigma errors are given for this fit). The time-integrated spectrum of the main emission episode (measured from T0+172.288 to T0+213.248 s) is well fit in the 20 keV - 5 MeV range by a power law with exponential cutoff model, for which: alpha = -1.50 (-0.2, +0.2), and Ep = 190(-44, +110) keV, chi2 = 59.2/75 dof. Fitting this spectrum with the GRB (Band) function yields the following model parameters: the low-energy photon index alpha = -1.5 (-0.2, +0.3), the high energy photon index beta = -2.4 (<-2.0), the peak energy Ep = 175(-73, +96) keV, chi2 = 58.2/74 dof. The spectrum at the maximum count rate (measured from T0+180.480 to T0+188.672 s) is best fitted is best fit in the 20 keV - 5 MeV range by a power law with exponential cutoff model, for which: alpha = -1.1 (-0.3, +0.3), and Ep = 180(-37, +68) keV, chi2 = 66.5/75 dof. All the quoted results are preliminary. All the quoted errors are at the 90% confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13489 SUBJECT: GRB 120716A: Candidate Optical Afterglow from PTF DATE: 12/07/19 00:01:37 GMT FROM: S. Bradley Cenko at Caltech S. B. Cenko (UC Berkeley), E. O. Ofek (Weizmann Institute of Science), and P. E. Nugent (Lawrence Berkeley National Laboratory / UC Berkeley) report on behalf of a larger collaboration: We have imaged the location of the IPN GRB 120716A (Hurley et al., GCN 13487) with the Palomar 48 inch Oschin Schmidt telescope as part of the Palomar Transient Factory (PTF). Images were obtained in the r' filter beginning at 4:25 UT on 18 July 2012 (~ 1.5 d after the IPN trigger). Within the IPN localization, we identify a new point source with coordinates: RA: 20:52:12.10 Dec: +09:35:53.7 (J2000.0) Using several nearby stars from the Sloan Digital Sky Survey for reference, we measure a magnitude of r' ~ 20.4 at this time. Nothing is detected at this location in previous PTF imaging of this field, with images beginning in June 2011. Furthermore, no source is detected in archival SDSS imaging of this location (a faint nearby object in the SDSS database, SDSS J205212.01+093551.9, appears to be of very low significance). However, our most recent epoch of PTF imaging was obtained in March 2012, so we cannot currently rule out the chance alignment of an unassociated foreground or background transient. Further observations of this candidate optical afterglow are planned. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13490 SUBJECT: GRB 120716A: Optical decay from NOT DATE: 12/07/19 05:52:35 GMT FROM: Dong Xu at Weizmann Inst D. Xu (WIS), N. Groeneboom, K. Mikkelsen (U. Oslo) report on behalf of a larger collaboration: We observed the field of the candidate optical afterglow (Cenko et al., GCN 13489) of GRB 120716A (Hurley et al., GCN 13487), using the 2.5m Nordic Optical Telescope (NOT) equipped with ALFOSC. Observations started 04:03 UT on 2012-07-19 (i.e., 2.455 days after the IPN trigger) and 5x300s SDSS r'-band images were obtained in a seeing of ~0.7". The optical source reported in GCN 13489 is well detected in each NOT image at coordinates RA(J2000)=20:52:12.17 Dec(J2000)=+09:35:53.9 with an uncertainty of ~0.1 arcsec radius, being consistent with the PTF position. The source had r(AB)=20.10+/-0.04, calibrated with nearby SDSS stars. The decay between the PTF and NOT epochs indicates that the source may be the optical afterglow of GRB 120716A. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13491 SUBJECT: GRB 120716A: Typo correction in GCN 13490 DATE: 12/07/19 06:10:16 GMT FROM: Dong Xu at Weizmann Inst D. Xu (WIS) reports The magnitude in GCN 13490 should be r'(AB)=21.00 rather than r'(AB)=20.10. Otherwise there would be no decay compared with the previous PTF magnitude of r'~20.4. Thanks to Brad Cenko for pointing out this. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13492 SUBJECT: GRB 120716A: GROND confirmation of the optical/NIR afterglow DATE: 12/07/19 06:26:31 GMT FROM: Patricia Schady at MPE/Swift P. Schady (MPE Garching), M. Nardini (Universita degli studi di Milano-Bicocca ) and J. Greiner (MPE Garching) report on behalf of the GROND team: We observed the field of GRB 120716A (Hurley et al., GCN #13487) at the position of the afterglow candidate (Cenko et al., GCN #13489) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG/ESO telescope at La Silla Observatory (Chile). Observations started at 05:07 UT on 2012-07-19, 2.5 days after the GRB trigger. They were performed at an average seeing of 1.4" and at an average airmass of 1.3. We found a single point source at a position consistent the afterglow candidate reported in Cenko et al. (GCN #13489) and Xu et al. (GCN #13490). Based on the first 460s of total exposures in g'r'i'z' and 480 s in JHK, we estimate preliminary magnitudes (all in AB system) of g' = 21.8 +- 0.1 mag, r' = 20.9 +- 0.1 mag, i' = 20.5 +- 0.1 mag, z' = 20.3 +- 0.1 mag, J = 19.9 +- 0.2 mag, H = 19.6 +- 0.2 mag and K = 18.8 +- 0.5 mag The optical/NIR SED is well fit by a power-law with a spectral slope of ~1.3, typical for GRB afterglows, confirming this to be the afterglow of GRB120716A. Given magnitudes are calibrated against SDSS zeropoints as well as 2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.07 mag in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13493 SUBJECT: VLT/FORS2 redshift of GRB120716A DATE: 12/07/19 08:40:51 GMT FROM: Arne Rau at MPE Jochen Greiner, Arne Rau, Patricia Schady (all MPE), Ivo Saviane (ESO), and Brad Cenko ( UC Berkeley) report on behalf of a larger collaboration. We observed the afterglow candidate of GRB 120716A (Hurley et al., GCN 13454; Cenko et al. GCN 13489; Xu et al, GCN 13490; Schady et al. CGN 13492) with the ESO VLT equipped with the FORS2 spectrograph. Observations with the 600B grism, covering a spectral range of 350-610nm) started at ~06:54 UT on July 19th 2012 (~58.2 hr after the gamma-ray trigger) and lasted for ~ 1.5hr. The spectrum shows a prominent, broad absorption trough centered at ~4250A, interpreted as Lyman-alpha, together with numerous metal lines (SiII, OI, SiIV, CIV) at longer wavelength. We find a common redshift of these features of z=2.48. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13494 SUBJECT: GRB 120716A: Redshift confirmation from VLT/X-shooter DATE: 12/07/19 16:56:53 GMT FROM: Valerio D'Elia at ASDC V. D'Elia (ASDC/INAF-OAR), P. Goldoni (APC,CEA/Irfu), D. Xu (WIS), T. Kruehler, J. P. U. Fynbo, D. Malesani (DARK/NBI), O.E. Hartoog (UvA, Netherland), N. R. Tanvir (U. of Leicester)   report  on behalf of the X-shooter GRB GTO collaboration: We observed the GRB 120716A (Hurley et. al GCN 13487) optical counterpart (Cenko et al. GCN 13489, Xu et al. GCN 13490, Schady et al. GCN 13492) with X-shooter at the VLT (Paranal, Chile). Observations started on 19 July at 8:40 UT (2.6 days after the burst) and consisted of a total observing time of 3600 s in each of the UVB, VIS and NIR arms, covering the range between 3000 and 18000 A. The spectrum shows a broad absorption trough at ~4250A which we interpret as due to Lyman-alpha. At the same redshift z=2.486 we detect plenty of metal absorption lines, such as (CII, SiII, OI, FeII, CIV, SiIV), fine structure (CII*, SiII* FeII*) and metastable (NiII) lines. We thus confirm the redshift reported by Greiner et al. (GCN 13493). We acknowledge excellent support from the ESO staff, in particular Dimitri Gadotti, Lorena Faundez, Fernando Selman and Jonathan Smoker. ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13495 SUBJECT: GRB 120716A: Swift/XRT position consistent with that of the optical counterpart DATE: 12/07/19 18:22:19 GMT FROM: Dong Xu at Weizmann Inst D. Xu (WIS) reports on behalf of a larger collaboration: The Swift satellite observed the field of the decaying optical transient (Cenko et al. GCN 13489; Xu et al. GCN 13490; Schady et al. GCN 13492), which is very likely the optical afterglow of GRB 120716A (Hurley et al., GCN 13487). Initial observation started at 12:47 UT and ended at 13:12 UT on 2012-07-19 (i.e., a median time of 2.83 d after the IPN trigger), and consisted of a total observing time of 1470s for Swift/XRT. Preliminary XRT data reduction reveals a S/N~2 source at coordinates RA(J2000) = 20:52:12.4 Dec(J2000) = +09:35:51.1 with an uncertainty of 7.7 arcsec radius, being consistent with the position of the optical source. Currently we don't know whether the X-ray source is decaying or not. We thank the Swift team for carrying out a quick ToO observation. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13496 SUBJECT: GRB 120716A: Swift-XRT detection DATE: 12/07/19 19:15:34 GMT FROM: Valerio D'Elia at ASDC V. D'Elia (ASDC), J. Gelbord and J. Kennea (PSU) report on behalf of the Swift-XRT team: Swift began a target of opportunity observation of GRB120716A on July 19, 2012 at 14:22 UT, approximately 2.9 days after the discovery (Hurley et al. GCN 13487). Swift data for these observations utilize Target ID 20225. Preliminary analysis of the 1.5 ks downlinked XRT data finds an uncatalogued X-ray source at RA, Dec = 313.05050, 9.59850 which is equivalent to: RA(J2000) =  20h 52m 12.12s Dec(J2000)= +09d 35m 54.6s, with an error radius of 3.4 arcsecs (position enhanced by UVOT field astrometry). The above position is consistent with the optical afterglow detection reported by Cenko et al. (GCN 13489), Xu et al. (GCN 13490), Schady et al. (GCN 13492). In addition, no known X-ray object is present at the XRT coordinates, so this is likely the X-ray afterglow of GRB120716A. The count rate of the XRT source is 8.32E-03+/-2.9E-03 cts/s. We cannot determine at the present time whether the source is fading. This circular is an official product of the Swift-XRT team. ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13497 SUBJECT: GRB 120716A: EVLA Detection DATE: 12/07/19 22:26:20 GMT FROM: Ashley Zauderer at CfA A. Zauderer, T. Laskar, A. Soderberg and E. Berger (Harvard) report on behalf of a larger collaboration: "We observed the position of GRB 120716A (Hurley et al.; GCN 13487) with the EVLA beginning 2012 July 19.26 (dt ~ 2.5 d). At a mean frequency of 6 and 22 GHz, we detect a radio source (10 and 6 sigma, respectively) consistent with optical candidates (e.g. Cenko et al.; GCN 13489) and the Swift-XRT detection (D'Elia et al.; GCN 13496). Followup observations are planned." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13498 SUBJECT: GRB 120716A: Fermi GBM observation DATE: 12/07/20 11:21:05 GMT FROM: David Gruber at MPE David Gruber (MPE) and Adam Goldstein (UAH) report on behalf of the Fermi GBM Team: "At 17:05:03.91 UT on 16 July 2012, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 120716A (trigger 364151106 / 120716712). This burst was localized by the IPN (Hurley et al., GCN 13487). The GBM on-ground calculated location is consistent with the IPN location. The angle from the Fermi LAT boresight is 63 degrees. This burst was also independently detected by INTEGRAL SPI-ACS. The GBM light curve consists of a bright precursor, followed by a double-peaked main emission after ~ 160 s. The duration (T90) is about 234 s (50-300 keV). The time-averaged spectrum of the precursor is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.84 +/- 0.11 and the cutoff energy, parameterized as Epeak, is 173 +/- 18 keV. A Band function fits the spectrum equally well with Epeak= 115 +/- 19 keV, alpha = -0.48 +/- 0.22 and beta = -2.19 +/- 0.17. The time-averaged spectrum of the main emission is best fit by a Band function with Epeak= 114 +/- 12 keV, alpha = -1.00 +/- 0.08 and beta= -2.08 +/- 0.07. The event fluence (10-1000 keV) is (1.47 +/- 0.01)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0-0.13 s in the 10-1000 keV band is 8.37 +/- 0.32 ph/s/cm^2. Using the redshift of 2.48 (Greiner et al., GCN 13493; D'Elia et al., GCN 13494) and a standard cosmology model with H_0 = 71 km/s/Mpc, Omega_M = 0.27, Omega_Lambda = 0.73, this corresponds to an isotropic energy release of ~ 3E+53 erg. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13518 SUBJECT: GRB 120716A: optical observation in CrAO DATE: 12/07/25 19:24:53 GMT FROM: Alexei Pozanenko at IKI, Moscow V. Rumyantsev, N. Pit (CrAO), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the region of optical afterglow (Cenko et al., GCN 13489) of IPN localized GRB 120716A (Hurley et al., GCN 13487) with AZT-11 telescope of CrAO observatory starting on July 19 (UT) 18:51 under seeing of about 3.3 arsces. We do not detected optical afterglow up to R=20.8. The photometry is based on the USNO-B1.0 star 0996-0576906 (20 52 01.46 +09 36 17.8) assuming R=15.97: T0+ Filter, Exposure, OT, uplim (3 sigma) (mid, d) (s) 2.0972 R 22x180 n/d 20.8 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13523 SUBJECT: GRB 120716A: optical observation in Maidanak observatory DATE: 12/07/28 14:43:32 GMT FROM: Alexei Pozanenko at IKI, Moscow A. Pozanenko (IKI), A. Sergeev (Institute of Radio Astronomy NASU), A. Volnova (SAI MSU), O. Burhonov (UBAI), I. Molotov (KIAM) report on behalf of larger GRB follow-up collaboration: We observed the region of the optical afterglow (Cenko et al., GCN 13489) of IPN localized GRB 120716A (Hurley et al., GCN 13487) with AZT-22 telescope of Maidanak observatory on Jul. 19 (UT) 17:57:06 and Jul. 21 (UT) 18:46:16 under mean seeing of about 0.6 arcsec. Totally we obtained 8 images of 600 s exposure in R filter. In each particular image we clearly see the optical afterglow (Cenko et al., GCN 13489; Xu et al., GCN 13490; Schady et al., GCN 13492) in coordinates (J2000) 20:52:12.15 +09:35:54.2 (uncertainty of 0.13 arcsec in both coordinates). Preliminary photometry of the afterglow is based on USNO-B1.0 nearby stars: T0+ Filter, Exposure, OT (mid, d) (s) date t_start (UT) filter exp,s OT 2012-07-19 17:57:06 R 4*600 20.71+/-0.04 2012-07-21 18:46:16 R 4*600 21.01+/-0.04