//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18643 SUBJECT: GRB 151127A: Swift detection of a short burst DATE: 15/11/27 09:24:29 GMT FROM: David Palmer at LANL A. D'Ai (INAF-IASFPA), P. A. Evans (U Leicester), A. Maselli (INAF-IASFPA), K. L. Page (U Leicester), D. M. Palmer (LANL) and T. Sakamoto (AGU) report on behalf of the Swift Team: At 09:08:49 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 151127A (trigger=665268). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 19.778, -82.774 which is RA(J2000) = 01h 19m 07s Dec(J2000) = -82d 46' 25" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single peak structure with a duration of about 0.5 sec. The peak count rate was ~3000 counts/sec (15-350 keV), at ~0.15 sec after the trigger. The XRT began observing the field at 09:10:09.0 UT, 79.2 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 19.4797, -82.7707 which is equivalent to: RA(J2000) = 01h 17m 55.13s Dec(J2000) = -82d 46' 14.5" with an uncertainty of 2.6 arcseconds (radius, 90% containment). This location is 135 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 1.02 x 10^21 cm^-2 (Willingale et al. 2013). UVOT took a finding chart exposure of 150 seconds with the White filter starting 77 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 none of the XRT error circle. 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 0.12. Burst Advocate for this burst is A. D'Ai (antonino.dai AT ifc.inaf.it). 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: 18644 SUBJECT: GRB 151127A: LCOGT-SSO optical upper limits DATE: 15/11/27 12:51:46 GMT FROM: Dong Xu at NAOC/CAS D. Xu (NAOC/CAS), D. Malesani (DARK/NBI), Y. Qin (Geneva Observatory), Y.-H. Han (NAOC/CAS, HUST), and Y.-D. Hu (IAA-CSIC) report: We observed the field of the short GRB 151127A (D'Ai et al., GCN 18643) with the 1-m LCOGT telescope at the Siding Spring Observatory. Observations started 27.42 UT on 2015-11-27 (i.e., 1.04 hr after the GRB), and we obtained 5x180s R-band and 8x180s I-band images. No new source is detected inside or close to the XRT position (D'Ai et al., GCN 18643), down to 3-sigma upper limits of R > 20 mag and I > 19 mag (calibrated against nearby USNO stars), at mean times of 1.17 and 1.52 hr after the GRB, respectively. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18645 SUBJECT: GRB 151127A: GROND K-band upper limit DATE: 15/11/27 13:01:13 GMT FROM: Jochen Greiner at MPI T. Schweyer and J. Greiner (both MPE Garching) report on behalf of the GROND team: We observed the field of GRB 151127A (Swift trigger 665268; D'Ai et al., GCN #18643) simultaneously in JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at the ESO La Silla Observatory (Chile). Observations started at 09:12:30 UT on 2015-11-27, about 4 min after the GRB trigger. They were performed at an average seeing of 2" and at an average airmass of 2.3 during morning twilight, with the Sun at -6 deg. Due to the sky brightness, only the first two 1-min exposure K-band images are useful. We do not detect a source within the 2.6 arcsecond XRT error circle (D'Ai et al., GCN #18643), down to a limiting magnitude of K(AB) > 16.5 mag. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18646 SUBJECT: GRB151127A: Planned XMM-Newton observation DATE: 15/11/27 14:31:35 GMT FROM: Norbert Schartel at XMM-Newton/ESA XMM-Newton will observe GRB GRB151127A at location (RA=01h 17m 55.13s, DEC=-82d 46' 14.5", J2000), starting at 13:35:45 UT, on November 28, 2015, for an exposure of 17500 seconds. This message and any attachments are intended for the use of the addressee or addressees only. The unauthorised disclosure, use, dissemination or copying (either in whole or in part) of its content is not permitted. If you received this message in error, please notify the sender and delete it from your system. Emails can be altered and their integrity cannot be guaranteed by the sender. Please consider the environment before printing this email. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18647 SUBJECT: GRB 151127A: Enhanced Swift-XRT position DATE: 15/11/27 16:07:42 GMT FROM: Phil Evans at U of Leicester M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team. Using 466 s of XRT Photon Counting mode data and 1 UVOT images for GRB 151127A, 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 = 19.47835, -82.77070 which is equivalent to: RA (J2000): 01h 17m 54.80s Dec (J2000): -82d 46' 14.5" 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: 18648 SUBJECT: GRB 151127A: Swift-BAT refined analysis DATE: 15/11/27 16:48:26 GMT FROM: Scott Barthelmy at NASA/GSFC T. Sakamoto (AGU), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), A. D'Ai (INAF-IASFPA), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), 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-60 to T+243 sec from recent telemetry downlinks, we report further analysis of BAT GRB 151127A (trigger #665268) (D'Ai, et al., GCN Circ. 18643). The BAT ground-calculated position is RA, Dec = 19.664, -82.762 deg, which is RA(J2000) = 01h 18m 39.4s Dec(J2000) = -82d 45' 42.1" with an uncertainty of 2.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 96%. The mask-weighted light curve shows a single spike starting at T_zero and ending at ~T+0.25 sec. T90 (15-350 keV) is 0.19 +- 0.04 sec (estimated error including systematics). The time-averaged spectrum from T+0.016 to T+0.220 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.26 +- 0.33. The fluence in the 15-150 keV band is 2.3 +- 0.6 x 10^-8 erg/cm2. The 1-sec peak photon flux measured from T-0.38 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/665268/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18649 SUBJECT: GRB 151127A: Swift-XRT refined Analysis DATE: 15/11/27 17:09:09 GMT FROM: Phil Evans at U of Leicester P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. D'ai (INAF-IASFPA), T.G.R. Roegiers (PSU), L.M. McCauley (PSU), J.A. Kennea (PSU), S.L. Gibson (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester) and A. D'Ai report on behalf of the Swift-XRT team: We have analysed 8.2 ks of XRT data for GRB 151127A (D'Ai et al. GCN Circ. 18643), from 80 s to 18.4 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Goad et al. (GCN Circ. 18647). The light curve can be modelled with a power-law decay with a decay index of alpha=1.15 (+0.17, -0.15). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.3 (+0.7, -0.5). The best-fitting absorption column is 1.6 (+1.6, -0.6) x 10^21 cm^-2, consistent with the Galactic value of 1.0 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 2.9 x 10^-11 (4.4 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.6 (+1.6, -0.6) x 10^21 cm^-2 Galactic foreground: 1.0 x 10^21 cm^-2 Excess significance: <1.6 sigma Photon index: 2.3 (+0.7, -0.5) If the light curve continues to decay with a power-law decay index of 1.15, the count rate at T+24 hours will be 1.4 x 10^-4 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.2 x 10^-15 (6.4 x 10^-15) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00665268. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18650 SUBJECT: GRB 151127A: Swift/UVOT Upper Limits DATE: 15/11/27 18:22:40 GMT FROM: Sam Emery at MSSL-UCL S.W.K Emery (UCL-MSSL) and A. D'Ai (INAF-IASFPA) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 151127A 77 s after the BAT trigger (D'Ai et al., GCN Circ. 18643). No optical afterglow consistent with the XRT position (Goad et al. GCN Circ. 18647) 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 77 227 147 >20.8 white 77 1017 295 >21.2 w1 668 6559 452 >20.3 m2 816 6354 432 >20.0 w2 594 18458 1696 >21.3 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.12 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18656 SUBJECT: GRB 151127A iTelescope observation DATE: 15/12/02 13:35:18 GMT FROM: Takanori Sakamoto at AGU Y. Kitaoka, T. Sakamoto, A. Yoshida (AGU) We observed the field of GRB 151127A detected by Swift (trigger #665268; D'Ai et al., GCN Circ. 18643) with the iTelescope.Net (http://www.itelescope.net) T30 (20" Plane Wave) telescope located at the Siding Spring Observatory (New South Wales, Australia). 20 images of 60 sec exposures were taken in the R filter starting from November 27 09:47:56 (UT) about 39.1 minutes after the trigger and stopped on November 27 10:23:18 (UT). We do not detect the optical afterglow both in the individual images and the stacked image at the enhanced X-ray afterglow position (Goad et al., GCN Circ. 18647). The estimated five sigma upper limit of the combined image (total exposure of 1200 sec) is ~18.2 using the USNO-B1 catalog.