//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16732 SUBJECT: GRB 140824A: Swift detection of a burst DATE: 14/08/24 08:55:04 GMT FROM: Hans Krimm at NASA-GSFC A. P. Beardmore (U Leicester), H. A. Krimm (CRESST/GSFC/USRA), C. J. Mountford (U Leicester) and K. L. Page (U Leicester) report on behalf of the Swift Team: At 08:40:28 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 140824A (trigger=610501). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 206.644, +33.297 which is RA(J2000) = 13h 46m 35s Dec(J2000) = +33d 17' 50" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peaked structure with a duration of about 5 sec. The peak count rate was ~2700 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began observing the field at 08:41:43.2 UT, 75.1 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 206.6168, 33.2935 which is equivalent to: RA(J2000) = 13h 46m 28.03s Dec(J2000) = +33d 17' 36.6" with an uncertainty of 2.2 arcseconds (radius, 90% containment). This location is 82 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 1.46 x 10^20 cm^-2 (Willingale et al. 2013). UVOT took a finding chart exposure of 150 seconds with the White filter starting 79 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 0.02. Burst Advocate for this burst is A. P. Beardmore (apb AT star.le.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: 16733 SUBJECT: GRB 140824A: Swift/UVOT Upper Limits DATE: 14/08/24 15:25:09 GMT FROM: Paul Kuin at MSSL N. P. M. Kuin (UCL-MSSL) and A. P. Beardmore (U Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 140824A 80 s after the BAT trigger (Beardmore et al., GCN Circ. 16732). No optical afterglow consistent with the XRT position (Beardmore et al. GCN Circ. 16732) 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 80 229 147 >21.0 u_FC 292 542 246 >20.2 white 80 6901 688 >21.9 v 5676 7226 309 >20.1 b 5061 6696 393 >20.9 u 292 6491 639 >20.6 w1 4651 6286 393 >20.0 m2 5881 11294 1082 >21.4 w2 5471 7107 393 >20.9 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16734 SUBJECT: GRB 140824A: MITSuME Ishigakijima upper limits DATE: 14/08/24 15:28:57 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 140824A (Beardmore et al., GCNC 16732) 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 2014-08-24 11:50:27 UT (~3.2 h after the burst). We did not find any new point source within the XRT circle (Beardmore et al., GCNC 16732) in all the three bands. Three sigma upper limits of the OT are listed below. We used SDSS catalog for flux calibration. #T0+[day] MID-UT T-EXP[sec] g' Rc Ic ----------------------------------------------------- 0.14409 12:07:58 1800.0 >21.7 >21.4 >20.5 ----------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16735 SUBJECT: GRB 140824A: Enhanced Swift-XRT position DATE: 14/08/24 15:46:54 GMT FROM: Phil Evans at U of Leicester P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team. Using 1996 s of XRT Photon Counting mode data and 3 UVOT images for GRB 140824A, 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 = 206.61710, +33.29376 which is equivalent to: RA (J2000): 13h 46m 28.10s Dec (J2000): +33d 17' 37.5" with an uncertainty of 1.7 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: 16736 SUBJECT: GRB 140824A: Swift-BAT refined analysis DATE: 14/08/24 17:21:26 GMT FROM: Hans Krimm at NASA-GSFC A. Y. Lien (NASA/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), 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), J. Tueller (GSFC), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-240 to T+714 sec from the recent telemetry downlink, we report further analysis of BAT GRB 140824A (trigger #610501) (Beardmore, et al., GCN Circ. 16732). The BAT ground-calculated position is RA, Dec = 206.627, 33.285 deg which is RA(J2000) = 13h 46m 30.4s Dec(J2000) = +33d 17' 05.1" with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 73%. The mask-weighted light curve shows a single peak with a FRED-like profile, starting at T+0 and lasting approximately five seconds. T90 (15-350 keV) is 3.09 +- 0.50 sec (estimated error including systematics). The time-averaged spectrum from T+0.26 to T+3.64 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.98 +- 0.21. The fluence in the 15-150 keV band is 1.9 +- 0.2 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.34 sec in the 15-150 keV band is 1.2 +- 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/610501/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16737 SUBJECT: GRB 140824A: Swift-XRT refined Analysis DATE: 14/08/24 21:55:03 GMT FROM: Phil Evans at U of Leicester A. Maselli (INAF-IASFPA), A. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), V. Mangano (PSU), M.C. Stroh (PSU), D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Pagani (U. Leicester) and A.P. Beardmore report on behalf of the Swift-XRT team: We have analysed 16 ks of XRT data for GRB 140824A (Beardmore et al. GCN Circ. 16732), from 85 s to 35.6 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Evans et al. (GCN Circ. 16735). The light curve can be modelled with a power-law decay with a decay index of alpha=0.90 (+/-0.05). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.87 (+0.27, -0.25). The best-fitting absorption column is 1.0 (+0.8, -0.7) x 10^21 cm^-2, in excess of the Galactic value of 1.5 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.6 x 10^-11 (4.3 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.0 (+0.8, -0.7) x 10^21 cm^-2 Galactic foreground: 1.5 x 10^20 cm^-2 Excess significance: 2.2 sigma Photon index: 1.87 (+0.27, -0.25) If the light curve continues to decay with a power-law decay index of 0.90, the count rate at T+24 hours will be 1.5 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.3 x 10^-14 (6.4 x 10^-14) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00610501. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16738 SUBJECT: GRB 140824A: OSN optical limit DATE: 14/08/24 22:08:45 GMT FROM: Javier Gorosabel at IAA-CSIC F. Espartero (IAA-CSIC), F.J. Aceituno (OSN/IAA-CSIC), J. Gorosabel (IAA-CSIC/UPV-EHU) and A.J. Castro-Tirado (IAA-CSIC/UMA), report on behalf of a larger collaboration: We observed the field of GRB140824A (Beardmore et al. 16732) with the 1.5m OSN telescope at Observatorio de Sierra Nevada (Spain). The observations were carried out in the Clear band on Aug 24.84965-24.88029 (11.72-12.45 hours post bust). We do not detect any optical source brighter than R~21 consistent with the XRT position (Evans et al. 16735). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16739 SUBJECT: GRB 140824A: NOT optical upper limits DATE: 14/08/24 22:56:03 GMT FROM: Dong Xu at DARK/NBI D. Xu (DARK/NBI), S. Covino (INAF-OAB), J. P. U. Fynbo (DARK/NBI), A. A. Djupvik, J. Harmanen (NOT), P. Jakobsson (U. Iceland) report on behalf of a larger collaboration: We observed the field of GRB 140824A (Beardmore et al., GCN 16732) using the 2.5m Nordic Optical Telescope (NOT) equipped with ALFOSC. We obtained 3x300s SDSS r-band and 6x200s SDSS z-band images with their median time of 12.41 hr and 12.88 hr after the burst, respectively. No optical source is detected at the XRT position (Evans et al., GCN 16735), down to the upper limits of r~24.0 mag and z~22.4 mag. Near-infrared follow-ups are encouraged. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16747 SUBJECT: GRB 140824A: optical upper limit in CrAO DATE: 14/08/26 18:11:29 GMT FROM: Alexei Pozanenko at IKI, Moscow V. Rumyantsev (CrAO), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of the Swift GRB 140824A (Beardmore et al., GCN 16732) with ZTSh telescope of CrAO observatory starting on Aug. 24 (UT) 17:48:55 (9.1 hours after burst trigger). We took several images in R-filter of 120 s exposure. Within enhanced XRT position (Evans et al., GCN 16735) we do not detect any source. Photometry of a combined image is following Date UT start, t-t0 Filter Exp. OT UL (3 sigma) (mid, days) (s) 2014-08-24 17:48:55 0.4105 R 39x120 n/d 23.5 The photometry is based on USNO-B1.0 star 1233-0239576 (13:46:31.55 +33:18:14.7) assuming R=19.66