//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16456 SUBJECT: GRB 140626A: Swift detection of a burst DATE: 14/06/26 00:47:35 GMT FROM: Scott Barthelmy at NASA/GSFC J. R. Cummings (NASA/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), V. D'Elia (ASDC), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), N. P. M. Kuin (UCL-MSSL), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC) and D. M. Palmer (LANL) report on behalf of the Swift Team: At 00:33:01 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 140626A (trigger=602604). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 77.350, -82.630 which is RA(J2000) = 05h 09m 24s Dec(J2000) = -82d 37' 46" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a double pulse structure with a duration of about 35 sec. The peak count rate was ~1500 counts/sec (15-350 keV), at ~5 sec after the trigger. The XRT began observing the field at 00:34:41.7 UT, 99.9 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 77.37387, -82.63218 which is equivalent to: RA(J2000) = 05h 09m 29.73s Dec(J2000) = -82d 37' 55.8" with an uncertainty of 4.0 arcseconds (radius, 90% containment). This location is 13 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. We cannot determine whether the source is fading at the present time. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 1.42 x 10^21 cm^-2 (Willingale et al. 2013). UVOT took a finding chart exposure of 150 seconds with the White filter starting 103 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 100% of the XRT 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 XRT 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 0.15. Burst Advocate for this burst is J. R. Cummings (jayc 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: 16458 SUBJECT: GRB 140626A: GROND Afterglow Candidate DATE: 14/06/26 02:43:50 GMT FROM: Alexander Kann at TLS Tautenburg M. Tanga, J. F. Graham (both MPE Garching), D. A. Kann (TLS Tautenburg), and J. Greiner (MPE Garching) report on behalf of the GROND team: We observed the field of GRB 140626A (Swift trigger 602604; Cummings et al., GCN #16456) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla Observatory (Chile). Observations started at 00:45:12 UT on June 26, 2014, 12 minutes after the GRB trigger. They were performed at an average seeing of 2.4 and at an average airmass of 2.5. We detect a source at the north-eastern edge of the the Swift-XRT error circle reported by Cummings et al., GCN #16456 at RA (J2000) = 05:09:30.79, Dec. (J2000) = -82:37:50.2, at AB magnitude: g' = 21.9 +/- 0.1 mag, r' = 20.9 +/- 0.1 mag, i' = 20.4 +/- 0.1 mag, and z' = 19.8 +/- 0.1 mag. This object is not detected in the DSS. We propose it to be the afterglow of GRB 140626A but at this time cannot ascertain fading. The magnitude was derived based on calibrating the image against the GROND zeropoint and is not corrected for the Galactic foreground extinction corresponding to a reddening of E_(B-V)= 0.15 mag in the direction of the burst (Schlegel et al. 1998). [GCN OPS NOTE(26jun14): Per author's request, the typo of the observation date in the second paragraph was changed from Jun 22 to Jun 26.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16459 SUBJECT: GRB 140626A: Enhanced Swift-XRT position DATE: 14/06/26 06:37:23 GMT FROM: Phil Evans at U of Leicester A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team. Using 1162 s of XRT Photon Counting mode data and 3 UVOT images for GRB 140626A, 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 = 77.38009, -82.63084 which is equivalent to: RA (J2000): 05h 09m 31.22s Dec (J2000): -82d 37' 51.0" with an uncertainty of 2.1 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) and Evans et al. (2009, MNRAS, 397, 1177). This circular was automatically generated, and is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16460 SUBJECT: GRB 140626A: Swift/UVOT Upper Limits DATE: 14/06/26 12:44:27 GMT FROM: Paul Kuin at MSSL N. P. M. Kuin (UCL-MSSL) and J. R. Cummings (NASA/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 140626A 103 s after the BAT trigger (Cummings et al., GCN Circ. 16456). No optical afterglow consistent with the XRT position (Beardmore et al. GCN Circ. 16459) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 103 253 147 >20.9 u_FC 262 511 246 >20.3 white 103 1538 392 >21.1 v 592 1590 117 >19.0 b 517 1514 97 >20.0 u 262 1489 343 >20.4 w1 642 1639 117 >19.4 m2 617 1440 39 >19.1 w2 568 1563 117 >19.9 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: 16461 SUBJECT: GRB 140626A: Swift-XRT refined Analysis DATE: 14/06/26 12:47:04 GMT FROM: Phil Evans at U of Leicester J.A. Kennea (PSU), B.P. Gompertz (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), M. de Pasquale (INAF-IASFPA), A. Maselli (INAF-IASFPA), A. Melandri (INAF-OAB), V. Mangano (PSU), M.C. Stroh (PSU) and J.R. Cummings report on behalf of the Swift-XRT team: We have analysed 8.5 ks of XRT data for GRB 140626A (Cummings et al. GCN Circ. 16456), from 86 s to 18.9 ks after the BAT trigger. The data comprise 7 s in Windowed Timing (WT) mode (taken while Swift was slewing), with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN Circ. 16459). The light curve can be modelled with a power-law decay with a decay index of alpha=0.52 (+/-0.11). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.06 (+0.34, -0.27). The best-fitting absorption column is 1.8 (+1.2, -0.4) x 10^21 cm^-2, consistent with the Galactic value of 1.4 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 3.4 x 10^-11 (4.6 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.8 (+1.2, -0.4) x 10^21 cm^-2 Galactic foreground: 1.4 x 10^21 cm^-2 Excess significance: <1.6 sigma Photon index: 2.06 (+0.34, -0.27) If the light curve continues to decay with a power-law decay index of 0.52, the count rate at T+24 hours will be 7.5 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.5 x 10^-13 (3.4 x 10^-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00602604. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16462 SUBJECT: GRB 140626A: Swift-BAT refined analysis DATE: 14/06/26 12:49:33 GMT FROM: Hans Krimm at NASA-GSFC M. Stamatikos (OSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 140626A (trigger #602604) (Cummings, et al., GCN Circ. 16456). The BAT ground-calculated position is RA, Dec = 77.163, -82.625 deg which is RA(J2000) = 05h 08m 39.1s Dec(J2000) = -82d 37' 29.5" with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The mask-weighted light curve shows a double-peaked structure. The first peak extends from T-10 sec to T+0 sec, while the second, comparably-sized peak extends from T+0 sec to T+10 sec. T90 (15-350 keV) is 16.4 +- 1.4 sec (estimated error including systematics). The time-averaged spectrum from T-8.94 to T+9.08 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.61 +- 0.88, and Epeak of 44.7 +- 9.5 keV (chi squared 45.83 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 3.6 +- 0.5 x 10^-7 erg/cm2 and the 1-sec peak flux measured from T+5.68 sec in the 15-150 keV band is 0.7 +- 0.1 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.91 +- 0.17 (chi squared 54.28 for 57 d.o.f.). 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/602604/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16469 SUBJECT: GRB 140626A: TAROT La Silla observatory optical observations DATE: 14/06/28 16:54:48 GMT FROM: Alain Klotz at IRAP-CNRS-OMP Klotz A., Turpin D. (IRAP-CNRS-OMP), Boer M., Gendre B., Siellez K., Dereli H., Bardho O. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report: We imaged the field of GRB 140626A detected by SWIFT (trigger 602604) with the TAROT robotic telescope (D=25cm) located at the European Southern Observatory, La Silla observatory, Chile. The observations started 72.1s after the GRB trigger (15.9s after the notice). The elevation of the field decreased from 23 degrees above horizon and weather conditions were good. Images were not accessible during two days due to a disk access problem. The first image is trailed with a duration of 60.0s (see the description in Klotz et al., 2006, A&A 451, L39). We do not detect any OT with a limiting magnitude of: t0+72.1s to t0+132.1s : R > 16.6 The second image is 30.0s exposure in tracking mode: t0+145.4s to t0+175.4s : R > 17.6 We co-added a series of exposures: t0+145.4s to t0+437.3s : R > 19.2 Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction.