//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13471 SUBJECT: GRB 120714B: Swift detection of a burst DATE: 12/07/14 21:34:11 GMT FROM: Scott Barthelmy at NASA/GSFC C. J. Saxton (UCL-MSSL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), N. P. M. Kuin (UCL-MSSL), C. B. Markwardt (NASA/GSFC), S. R. Oates (UCL-MSSL), K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 21:18:46.57 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 120714B (trigger=526642). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 355.433, -46.186 deg, which is RA(J2000) = 23h 41m 44s Dec(J2000) = -46d 11' 08" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for image triggers (64 sec), the realtime TDRSS lightcurve does not show anything significant. The XRT began observing the field at 21:20:46.6 UT, 120.1 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 355.3993, -46.1764 which is equivalent to: RA(J2000) = +23h 41m 35.83s Dec(J2000) = -46d 10' 35.0" with an uncertainty of 5.2 arcseconds (radius, 90% containment). This location is 90 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 1.59e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT results will not be available until further data are processed. Burst Advocate for this burst is C. J. Saxton (cjs2 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: 13473 SUBJECT: GRB 120714B: Position Correction and Candidate Optical Afterglow DATE: 12/07/15 00:06:32 GMT FROM: Frank Marshall at GSFC F. E. Marshall (NASA/GSFC) and C. J. Saxton (UCL-MSSL) report on behalf of the Swift team: The positions reported for GRB 120714B in GCN Circular 13471 are incorrect because of an unusally large attitude error on the spacecraft. Using the initial UVOT exposure, we find the corrected XRT position is: RA (J2000) = 23h 41m 38.35s DEC (J2000) = -46d 11' 07" There is a candidate afterglow in the initial UVOT exposure of 36 seconds starting 129 seconds after the trigger. The source has a mag of 18.6 in the white filter and is located at the following position: RA (J2000) = 23h 41m 38.05s DEC (J2000) = -46d 11' 03" //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13477 SUBJECT: GRB 120714B: Redshift from VLT/X-shooter DATE: 12/07/15 08:22:43 GMT FROM: Antonio de Ugarte Postigo at IAA-CSIC J.P.U. Fynbo (DARK/NBI), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), V. D'Elia (ASDC, INAF), D. Xu (WIS), and D. Malesani (DARK/NBI) report on behalf of the X-shooter GRB GTO collaboration: We observed the field of GRB 120714B (Saxton et. al GCN 13471, Marshall & Saxton GCN 13473) with X-shooter at VLT (Paranal, Chile). Observations started on 15 July at 5:06 UT (7.8 hr after the burst) and consisted of a total observing time of 4800 s in each of the UVB, VIS and NIR arms, covering the range between 3000 and 18000 A. The spectrum shows a faint continuum where we detect MgII absorption as well as emission lines of [OII], H-beta, [OIII] and H-alpha at a common redshift of z=0.3984. We acknowledge excellent support from the ESO staff, in particular Dimitri Gadotti. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13478 SUBJECT: GRB 120714B: GROND confirmation of fading afterglow DATE: 12/07/15 08:26:41 GMT FROM: Jochen Greiner at MPI A. Nicuesa Guelbenzu, S. Klose (both TLS Tautenburg), and J. Greiner (MPE Garching) report on behalf of the GROND team: We observed the field of GRB 120714B (Swift trigger 526642; Saxton et al., GCN 13471) simultaneously in g'r'i'z'JHKs 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 3:01 UT on 2012-07-15, about 6 hrs after the GRB trigger, at a airmass of 2.2, and a mean seeing of 2.4". Based on an exposure of 460 seconds in the optical and 480 seconds in the NIR, at a mean time of 03:27 UT we detect the UVOT afterglow candidate (Marshall et al., GCN 13473) with preliminary AB magnitudes g' = 22.3 +/- 0.2 r' = 22.1 +/- 0.2 i' = 21.5 +/- 0.2 z' = 20.5 +/- 0.2 J > 20.7 H > 20.1 Ks > 19.2. This suggests a fading relative to the white light magnitude of 18.6 mag as reported by Marshall et al. (GCN 13473), suggesting this to be the afterglow of GRB 120714B. Observations are ongoing. The magnitudes are derived based on GROND zeropoints (g'r'i'z') and 2MASS stars (JHK). We note that the Galactic reddening along the line of sight is E_(B-V)= 0.01 mag (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13481 SUBJECT: GRB 120714B: Swift-BAT refined analysis DATE: 12/07/15 17:34:09 GMT FROM: Scott Barthelmy at NASA/GSFC J. R. Cummings (GSFC/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), C. J. Saxton (UCL-MSSL), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-60 to T+243 sec from recent telemetry downlinks, we report further analysis of BAT GRB 120714B (trigger #526642) (Saxton, et al., GCN Circ. 13471). The BAT ground-calculated position is RA, Dec = 355.412, -46.196 deg, which is RA(J2000) = 23h 41m 38.9s Dec(J2000) = -46d 11' 47.3" with an uncertainty of 2.6 arcmin, (radius, sys+stat, 90% containment). The partial coding was 92%. The mask-weighted light curve shows a broad peak starting at ~T-35 sec, peaking around T+0 sec, and ending at ~T+55 sec with a tail out to ~T+150 sec. T90 (15-350 keV) is 159 +- 34 sec (estimated error including systematics). The time-averaged spectrum from T-23.0 to T+154.0 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.52 +- 0.17. The fluence in the 15-150 keV band is 1.2 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T-21.71 sec in the 15-150 keV band is 0.4 +- 0.1 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/526642/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13483 SUBJECT: GRB 120714B: Swift-XRT refined Analysis DATE: 12/07/16 09:17:01 GMT FROM: Owen Littlejohns at U of Leicester O. M. Littlejohns, K. Page (U. Leicester) & C. J. Saxton (UCL-MSSL) reports on behalf of the Swift-XRT team: We have analysed 2.4 ks of XRT data for GRB 120714B (Saxton et al. GCN Circ. 13471), from 110 s to 75.0 ks after the BAT trigger. The data comprise 9 s in Windowed Timing (WT) mode (taken while Swift was slewing), with the remainder in Photon Counting (PC) mode. The light curve can be modelled with a power-law decay with a decay index of alpha=1.87 (+0.13, -0.09). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.0 (+0.9, -0.6). The best-fitting absorption column is 1 (+11, -0) x 10^20 cm^-2, consistent with the Galactic value of 1.2 x 10^20 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.4 x 10^-11 (3.6 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1 (+11, -0) x 10^20 cm^-2 Galactic foreground: 1.2 x 10^20 cm^-2 Excess significance: <1.6 sigma Photon index: 2.0 (+0.9, -0.6) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00526642. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13484 SUBJECT: GRB 120714B: Swift/UVOT Detection DATE: 12/07/16 17:33:51 GMT FROM: Paul Kuin at MSSL N. P. M. Kuin (MSSL-UCL), F. Marshall (NASA/GSFC), and C. J. Saxton (UCL-MSSL) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 120714B 129 s after the BAT trigger (Saxton et al., GCN Circ. 13471). The UVOT source candidate reported by Marshall and Saxton (GCN Circ. No. 13473) is found to decay. The preliminary UVOT position is RA, Dec (J2000) = (355.40864,-46.18387), or in sexagesimal coordinates: RA = 23h41m38.1s Dec = -46d11'02" with 90% confidence error radius of 0.58". Preliminary detections and 3-sigma upper limits 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 129 165 35 18.40 +/- 0.20 white 10034 10184 147 >20.8 b 10195 11102 885 >21.5 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.01 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13613 SUBJECT: GRB 120714B: GROND/FORS2 detection of a supernova DATE: 12/08/09 18:34:32 GMT FROM: Sylvio Klose at TLS Tautenburg S. Klose (TLS), J. Greiner (MPE), J. Fynbo (DARK), A. Nicuesa Guelbenzu, S. Schmidl (both TLS), A. Rau (MPE), T. Kruehler (DARK), report on behalf of a larger collaboration: GROND has been following the afterglow of GRB 120714B (Saxton et al., GCN 13471) at z=0.398 (Fynbo et al., GCN 13477) since July 15 (Nicuesa Guelbenzu et al., GCN 13478). The light of the optical transient has been fading in all GROND optical bands during the first 1.5 days, was then flattening in r',i',z', and finally rising at about 3 days after the trigger (while it is flattening in g'). The data suggested that this behavior can be interpreted as an upcoming supernova component with a an early rise similar to the SN associated with GRB 011121 at z=0.36 (Bloom et al. 2002, ApJ 672, 45; Garnavich et al. 2003, ApJ 582, 924; Greiner et al. 2003, ApJ 599, 1223; Price et al. 2002, ApJ 572, 51). Spectroscopy of the optical transient with VLT/FORS2 was performed on August 1/2, 18.3 days after the burst. Observations were done with the 300V grism, covering the wavelength range from 445 to 865 nm, and lasted 7200 sec. The spectrum reveals very broad features in the continuum with a prominent peak around 6500 A and broad lines of Si II and Ca II, in agreement with a broad-lined SN dominating the light of the optical transient. At present a decision between type Ib and Ic cannot be performed due to an uncomfortable presence of atmospheric features in the spectrum. We thank the staff at ESO Paranal and ESO Garching for their excellent support and for performing the spectroscopy. GROND observations are continuing.