//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20145 SUBJECT: GRB 161108A: Swift detection of a burst DATE: 16/11/08 03:49:46 GMT FROM: David Palmer at LANL A. P. Beardmore (U Leicester), N. Gehrels (NASA/GSFC), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 03:32:33 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 161108A (trigger=721234). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 180.784, +24.869 which is RA(J2000) = 12h 03m 08s Dec(J2000) = +24d 52' 09" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 30 sec. The peak count rate was ~800 counts/sec (15-350 keV), at ~3 sec after the trigger. The XRT began observing the field at 03:33:53.5 UT, 80.3 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source located at RA, Dec 180.78748, 24.86801 which is equivalent to: RA(J2000) = 12h 03m 09.00s Dec(J2000) = +24d 52' 04.8" with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 11 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. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 1.79 x 10^20 cm^-2 (Willingale et al. 2013). The initial flux in the 2.5 s image was 8.63e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 90 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: 20146 SUBJECT: GRB 161108A: NOT candidate afterglow DATE: 16/11/08 06:08:47 GMT FROM: Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst D. Malesani (DARK/NBI and DTU Space), A. de Ugarte Postigo (IAA-CSIC and DARK/NBI), A. Somero (UTU), E. Gafton (NOT, SU, OKC), S. Damsted (Univ. Helsinki), G. Erfanianfar (MPE), A. Finoguenov (Univ. Helsinki), C. Gibson (Univ. Helsinki), F. Kiefer (MPE), C. Kirkpatrick (Univ. Helsinki), M. Lumme (Univ. Helsinki), V. Oja (Univ. Helsinki), J. Rantakyla (Univ. Helsinki), I. Salmenpera (Univ. Helsinki), and M. Seppala (Univ. Helsinki), report on behalf of a larger collaboration: We observed the field of GRB 161108A (Beardmore et al., GCN 20145) with the Nordic Optical Telescope (NOT) equipped with the AlFOSC imager and spectrograph. Observations started on Nov 8.2132 UT (94.4 min after the GRB trigger) and were carried out in the r and z filters. Within the currently available XRT position (Beardmore et al., GCN 20145), we detect a single object, at coordinates (J2000): RA = 12:03:09.11 Dec = +24:52:04.9 This source has a magnitude r = 20.82 +- 0.05 AB, calibrated against nearby SDSS stars. The same object is visible in the SDSS archival images, at a significantly fainter magnitude r = 22.69 +- 0.20. It is classified as a galaxy with a photometric redshift of 0.50 +- 0.12. The most likely interpretation is that the object seen in the NOT images is the superposition of afterglow and host galaxy, so we consider the association with GRB 161108A secure. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20147 SUBJECT: GRB 161108A: Enhanced Swift-XRT position DATE: 16/11/08 11:23:14 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 3332 s of XRT Photon Counting mode data and 5 UVOT images for GRB 161108A, 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 = 180.78794, +24.86815 which is equivalent to: RA (J2000): 12h 03m 9.11s Dec (J2000): +24d 52' 05.3" with an uncertainty of 1.6 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: 20148 SUBJECT: GRB 161108A: Swift-XRT refined Analysis DATE: 16/11/08 14:19:15 GMT FROM: Phil Evans at U of Leicester L.M. McCauley (PSU), P.A. Evans (U. Leicester), S.L. Gibson (U. Leicester), J.P. Osborne (U. Leicester), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU) and A.P. Beardmore report on behalf of the Swift-XRT team: We have analysed 6.5 ks of XRT data for GRB 161108A (Beardmore et al. GCN Circ. 20145), from 73 s to 27.1 ks after the BAT trigger. The data comprise 263 s in Windowed Timing (WT) mode (the first 6 s were 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. 20147).Considering only the late-time light curve (from T0+4.5 ks), the source is fading with alpha >1.2. A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.20 (+/-0.04). The best-fitting absorption column is 2.20 (+0.15, -0.14) x 10^21 cm^-2, in excess of the Galactic value of 1.8 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 2.09 (+0.24, -0.22) and a best-fitting absorption column of 1.5 (+0.7, -0.6) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.3 x 10^-11 (4.4 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.5 (+0.7, -0.6) x 10^21 cm^-2 Galactic foreground: 1.8 x 10^20 cm^-2 Excess significance: 3.7 sigma Photon index: 2.09 (+0.24, -0.22) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00721234. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20149 SUBJECT: GRB 161108A: RATIR Afterglow Confirmation DATE: 16/11/08 14:29:23 GMT FROM: Nat Butler at Az State U Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), José A. de Diego (UNAM), Leonid Georgiev (UNAM), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report: We observed the field of GRB 161108A (Beardmore, et al., GCN 20145) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir from 2016/11 8.48 to 2016/11 8.54 UTC (7.87 to 9.34 hours after the BAT trigger), obtaining a total of 1.03 hours exposure in the r and i bands and 0.40 hours exposure in the Z, Y, J, and H bands. The afterglow candidate reported by Malesani et al. (GCN 20146) is well detected. In comparison with the SDSS DR9 and 2MASS catalogs, we obtain the following detections and upper limits (3-sigma): r = 21.97 +/- 0.12 i = 21.36 +/- 0.06 Z = 20.88 +/- 0.11 Y = 20.57 +/- 0.14 J = 20.05 +/- 0.27 H > 18.12 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. The source appears to have faded in r by about 1 magnitude as compared to Malesani et al. (GCN 20146). We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20150 SUBJECT: GRB 161108A: NOT redshift DATE: 16/11/08 15:00:18 GMT FROM: Antonio de Ugarte Postigo at IAA-CSIC A. de Ugarte Postigo (IAA-CSIC and DARK/NBI), D. Malesani (DARK/NBI and DTU Space), D.A. Perley (DARK/NBI), J.P.U. Fynbo (DARK/NBI), K.E. Heintz (Univ. of Iceland and DARK/NBI), A. Somero (UTU), E. Gafton (NOT, SU, OKC), S. Damsted (Univ. Helsinki), G. Erfanianfar (MPE), A. Finoguenov (Univ. Helsinki), C. Gibson (Univ. Helsinki), F. Kiefer (MPE), C. Kirkpatrick (Univ. Helsinki), M. Lumme (Univ. Helsinki), V. Oja (Univ. Helsinki), J. Rantakyla (Univ. Helsinki), I. Salmenpera (Univ. Helsinki), and M. Seppala (Univ. Helsinki), report on behalf of a larger collaboration: Continuing with the observations of GRB 161108A (Beardmore et al., GCN 20145) reported by Malesani et al. (GCN 20146) we performed spectroscopy of the afterglow (see also Butler et al. GCN 20149) and host galaxy using the Nordic Optical Telescope (NOT) equipped with AlFOSC. The observation consisted of 2x1200s+1x600s exposures using grism 4, starting at 5:47 UT (2.25 hr after the burst). The spectrum shows continuum from 3900 to 9300 AA, with a single emission line at 8048 AA, consistent with being due to the [O II] doublet at z=1.159. Additionally we detect low SNR absorption features consistent with Mg II, Mg I, and Fe II at the same redshift, which we identify as the redshift of the GRB. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20151 SUBJECT: GRB 161108A, Swift-BAT refined analysis DATE: 16/11/08 22:14:28 GMT FROM: Amy Lien at GSFC D. M. Palmer (LANL), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 161108A (trigger #721234) (Beardmore, et al., GCN Circ. 20145). The BAT ground-calculated position is RA, Dec = 180.776, 24.905 deg which is RA(J2000) = 12h 03m 06.1s Dec(J2000) = +24d 54' 19.4" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 95%. The mask-weighted light curve shows a multi-peaked structure that starts at ~ T-5 s and ends at ~ T+ 130 s. The main peak occurs at ~T0. T90 (15-350 keV) is 105.1 +- 11.9 sec (estimated error including systematics). The time-averaged spectrum from T-1.9 to T+126.8 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.85 +- 0.17. The fluence in the 15-150 keV band is 1.1 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T-1.80 sec in the 15-150 keV band is 0.6 +- 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/721234/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20153 SUBJECT: GRB 161108A: TAROT Calern observatory optical observations DATE: 16/11/08 22:57:10 GMT FROM: Alain Klotz at IRAP-CNRS-OMP Klotz A., Turpin D., Atteia J.L. (CNRS-OMP-IRAP), Boer, M., Laugier, R. (CNRS-ARTEMIS), Gendre B. (UVI - Etelman Obs.) report: We imaged the field of GRB 161108A detected by SWIFT (trigger 721234) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France. The observations started 449s after the GRB trigger The elevation of the field increased from 28 degrees above horizon and weather conditions were good. We co-added a series of exposures but we did not detect the afterglow candidate of Malesani et al. (GCNC 20146). TAROT limiting magnitudes are: t0+ 449s to t0+ 539s : Rlim = 18.5 t0+1271s to t0+1941s : Rlim = 19.5 t0+1952s to t0+3694s : Rlim = 19.5 t0+3705s to t0+6041s : Rlim = 19.5 Magnitudes were estimated with the nearby NOMAD1 stars and are not corrected for galactic dust extinction. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20159 SUBJECT: GRB 161108A: Swift/UVOT Upper Limits DATE: 16/11/09 18:46:33 GMT FROM: Mike Siegel at PSU/Swift MOC M. H. Siegel (PSU) 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 161108A 90 s after the BAT trigger (Beardmore et al., GCN Circ. 20131). No optical afterglow consistent with the XRT position (Beardmore et al. GCN Circ. 20147) or the NOT position (Malesani et al., GCN Cir., 20146) 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 initial exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white (fc) 90 239 147 >20.08 white 90 5617 344 >20.62 v 578 6029 235 >18.61 b 5212 5412 196 >19.76 u 248 498 245 >19.24 u 248 10794 652 >19.88 uvw1 628 6439 412 >19.66 uvm2 603 6234 412 >19.89 uvw2 554 5823 235 >19.59 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: 20160 SUBJECT: GRB 161108A: TSHAO optical observations DATE: 16/11/09 21:29:59 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), A. Kusakin (Fesenkov Astrophysical Institute), I. Reva (Fesenkov Astrophysical Institute), A. Volnova (IKI), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of GRB 161108A (Beardmore et al., GCN 20145) with Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical Observatory. We obtained several images in R filter starting on Nov. 08 (UT) 23:06:16. Within enhanced XRT position (Beardmore et al., GCN 20147) we detected a source coinciding with the afterglow of GRB 161014A (Malesani et al., GCN 20146; Butler et al., GCN 20149). Preliminary photometry of the source is following Date UT start t-T0 Filter Exp. OT Err. UL (mid, days) (s) 2016-11-08 23:06:16 0.83869 R 28*120 21.8 0.20 22.0 Our photometry of the afterglow might be affected by nearby galaxy mentioned in GCN 20149 (Malesani et al.) Photometry is based on nearby SDSS-DR9 stars (Lupton transformations): SDSS-DR9_id R(Lupton) J120315.88+245217.4 18.37 J120326.17+245228.7 18.71 J120318.05+245356.7 18.52 J120250.21+245354.3 18.35 J120258.81+245024.2 16.90 J120314.67+244944.0 17.06 J120321.43+244829.2 16.79 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20163 SUBJECT: GRB 161108A: MITSuME Okayama upper limits DATE: 16/11/10 01:15:17 GMT FROM: Daisuke Kuroda at OAO/NAOJ D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ), S. Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of MITSuME and OISTER collaboration: We observed the field of GRB 161108A (Beardmore et al., GCNC 20145) with the optical three color (g', Rc and Ic) CCD camera attached to the MITSuME 50cm telescope of Okayama Astrophysical Observatory. The observation started on 2016-11-08 17:48:36 UT (~14.3 h after the burst). We could not detect the previously reported afterglow (Malesani et al., GCNC 20146; Butler et al., GCNC 20149) in all the three bands. Three sigma upper limits of the OT are listed below. We used SDSS-DR8 catalog for flux calibration. #T0+[day] MID-UT T-EXP[sec] g' Rc Ic ----------------------------------------------------- 0.63016 18:39:58 5940.0 >19.9 >19.6 >19.2 ----------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20167 SUBJECT: GRB 161108A: continued TSHAO optical observations DATE: 16/11/10 20:53:57 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), A. Kusakin (Fesenkov Astrophysical Institute), I. Reva (Fesenkov Astrophysical Institute), A. Volnova (IKI), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of GRB 161108A (Beardmore et al., GCN 20145) with Zeiss-1000 (East) 1-m telescope of Tien Shan Astronomical Observatory. We obtained several images in R filter starting on Nov. 09 (UT) 22:52:14. Within enhanced XRT position (Beardmore et al., GCN 20147) we detected the afterglow of GRB 161014A (Malesani et al., GCN 20146; Butler et al., GCN 20149). Preliminary photometry of the afterglow is following Date UT start t-T0 Filter Exp. OT Err. UL (mid, days) (s) 2016-11-09 22:52:14 1.83762 R 41*120 22.0 0.24 22.2 The photometry of the afterglow might be affected by nearby galaxy mentioned in GCN 20149 (Malesani et al.) Photometry is based on nearby SDSS-DR9 stars (Mazaeva et al., GCN 20160). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20200 SUBJECT: GRB 161108A: 15 GHz upper limits from AMI DATE: 16/11/21 18:19:57 GMT FROM: Kunal Mooley at Oxford U K. P. Mooley, T. D. Staley, R. P. Fender (Oxford), G. E. Anderson (Curtin), T. Cantwell (Manchester), D. Titterington, S. H. Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge), K. Grainge, A. Scaife (Manchester) The AMI Large Array robotically triggered on the Swift alert for GRB 161108A (Beardmore et al., GCN 20145) as part of the 4pisky program, and subsequent follow up observations were obtained up to 10 days post-burst. Our observations at 15 GHz on 2016 Nov 08.19, Nov 09.40, Nov 12.35 and Nov 15.36 (UT) do not reveal any radio source at the XRT location (Beardmore et al., GCN 20147), with 3sigma upper limits of 378 uJy, 284 uJy, 190 uJy and 93 uJy respectively. We thank the AMI staff for scheduling these observations. The AMI-GRB database is a log of all GRB follow up observations with the AMI, and is available at http://4pisky.org/ami-grb/.