//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18938 SUBJECT: GRB 160127A: Swift detection of a burst with an optical counterpart DATE: 16/01/27 09:05:29 GMT FROM: David Palmer at LANL A. Amaral-Rogers (U Leicester), A. P. Beardmore (U Leicester), P.A. Evans (U Leicester), A. Y. Lien (GSFC/UMBC), P. T. O'Brien (U Leicester), K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of the Swift Team: At 08:43:07 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 160127A (trigger=671828). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 225.956, +0.089 which is RA(J2000) = 15h 03m 49s Dec(J2000) = +00d 05' 20" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multiple-peaked structure with a duration of about 20 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 08:44:25.9 UT, 78.6 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 225.98136, 0.07222 which is equivalent to: RA(J2000) = 15h 03m 55.53s Dec(J2000) = +00d 04' 20.0" with an uncertainty of 3.8 arcseconds (radius, 90% containment). This location is 109 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 5.71 x 10^20 cm^-2 (Willingale et al. 2013). UVOT took a finding chart exposure of 150 seconds with the White filter starting 81 seconds after the BAT trigger. There is a candidate afterglow in the list of sources generated on-board at RA(J2000) = 15:03:55.70 = 225.98209 DEC(J2000) = +00:04:23.0 = 0.07305 with a 90%-confidence error radius of about 1.10 arc sec. This position is 3.9 arc sec. from the center of the XRT error circle. The estimated magnitude is 18.13. No correction has been made for the expected extinction corresponding to E(B-V) of 0.06. Burst Advocate for this burst is A. Amaral-Rogers (aar14 AT 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: 18939 SUBJECT: GRB 160127A: TAROT La Silla observatory optical light curve DATE: 16/01/27 12:14:43 GMT FROM: Alain Klotz at IRAP-CNRS-OMP Klotz A., Turpin D. (IRAP-CNRS-OMP), Boer M., Gendre B., Bardho O. (UNS-CNRS-OCA), Gendre B. (Etelman Observatory-UVI), Atteia J.L. (IRAP-CNRS-OMP) report: We imaged the field of GRB 160127A detected by SWIFT (trigger 671828) with the TAROT robotic telescope (D=25cm) located at the European Southern Observatory, La Silla observatory, Chile. The observations started 25.1s after the GRB trigger (13.4s after the notice). The elevation of the field increased from 42 degrees above horizon and weather conditions were good. We detected the candidate couterpart mentioned by Amaral-Rogers et al. (GCNC 18938). The first image is trailed with a duration of 60.0s (see the description in Klotz et al., 2006, A&A 451, L39). We detect the OT increasing its optical flux from t0+25s to t0+45s (R~16.9) and fading until the end of the trail at t0+85s. Following images were acquired in tracking mode: t1(s) t2(s) Rmag d_Rmag 99 129 17.9 0.6 141 171 17.4 0.1 182 212 17.1 0.7 223 253 17.1 0.0 306 396 17.1 0.2 407 497 17.4 0.4 610 700 17.6 0.1 711 801 17.6 0.2 914 1004 17.6 0.1 1015 1105 17.4 0.0 1742 1922 >18.4 0.6 Magnitudes were estimated with the stars: NOMAD1 0900-0248256 ra=225.9885561 dec=+00.0840197 R=14.83 NOMAD2 0901-0246538 ra=225.9533572 dec=+00.1320336 R=14.83 Magnitudes are not corrected for galactic dust extinction. After the first deacay observed in the trailed image from t0+45s to t0+85s, we observed a bump (maximum flux at t0+220s R~17.1) and we suspect a second bump (maximum flux at t0+1100s R~17.3) followed by a steep decay. The OT become fainter than 18.4 after t0+2000s. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18940 SUBJECT: GRB 160127A: Enhanced Swift-XRT position DATE: 16/01/27 12:39:17 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 1815 s of XRT Photon Counting mode data and 1 UVOT images for GRB 160127A, 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 = 225.98206, +0.07291 which is equivalent to: RA (J2000): 15h 03m 55.69s Dec (J2000): +00d 04' 22.5" 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: 18941 SUBJECT: GRB 160127A: RATIR Optical Observations DATE: 16/01/27 15:16:55 GMT FROM: Alan M. Watson at Instituto de Astronomia UNAM Antonino Cucchiara (GSFC/STScI), 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), 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 160127A (Amaral-Rogers et al., GCN 18938) 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 2016/01 27.39 to 2016/01 27.55 UTC (0.73 to 4.43 hours after the BAT trigger), obtaining a total of 2.68 hours exposure in the r,i and z bands. We detect the optical counterpart at RA, Dec = 15:3:55.77, +00:04:22.4 (J2000, +/-0.5”). In comparison with the SDSS DR9, we obtain the following magnitudes: r 20.64 +/- 0.03 i 20.66 +/- 0.03 z 20.14 +/- 0.32 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. Further observations are planned. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18943 SUBJECT: GRB 160127A: Swift-XRT refined Analysis DATE: 16/01/27 18:07:07 GMT FROM: Phil Evans at U of Leicester J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), S.L. Gibson (U. Leicester), A. D'Ai (INAF-IASFPA), A. Maselli (INAF-IASFPA), A. Melandri (INAF-OAB), D.N. Burrows (PSU) and A. Amaral-Rogers report on behalf of the Swift-XRT team: We have analysed 6.9 ks of XRT data for GRB 160127A (Amaral-Rogers et al. GCN Circ. 18938), from 65 s to 19.1 ks after the BAT trigger. The data comprise 121 s in Windowed Timing (WT) mode (the first 5 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 Evans et al. (GCN Circ. 18940). The late-time light curve (from T0+6.0 ks) can be modelled with a power-law decay with a decay index of alpha=1.6 (+/-0.3). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.65 (+0.23, -0.21). The best-fitting absorption column is 1.7 (+/-0.5) x 10^21 cm^-2, in excess of the Galactic value of 5.7 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.85 (+/-0.15) and a best-fitting absorption column of 9.7 (+4.4, -3.9) x 10^20 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.6 x 10^-11 (4.2 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 9.7 (+4.4, -3.9) x 10^20 cm^-2 Galactic foreground: 5.7 x 10^20 cm^-2 Excess significance: 1.7 sigma Photon index: 1.85 (+/-0.15) If the light curve continues to decay with a power-law decay index of 1.6, the count rate at T+24 hours will be 1.7 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 6.2 x 10^-14 (7.3 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/00671828. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18944 SUBJECT: GRB 160127A: Swift-BAT refined analysis DATE: 16/01/27 18:48:10 GMT FROM: Amy Lien at GSFC S. D. Barthelmy (GSFC), A. Amaral-Rogers (U Leicester), J. R. Cummings (GSFC/UMBC), 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-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 160127A (trigger #671828) (Amaral-Rogers et al., GCN Circ. 18938). The BAT ground-calculated position is RA, Dec = 225.966, 0.080 deg which is RA(J2000) = 15h 03m 51.8s Dec(J2000) = +00d 04' 46.7" with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 41%. The mask-weighted light curve shows a double-peaked structure that starts at ~ T-1 s and ends at ~ T+6 s. The two peaks occur at ~ T+1 and ~T+3 s, respectively. T90 (15-350 keV) is 6.16 +- 0.94 sec (estimated error including systematics). The time-averaged spectrum from T-1.44 to T+5.70 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.99 +- 1.11, and Epeak of 25.6 +- 0.0 keV (chi squared 44.15 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 3.3 +- 0.5 x 10^-7 erg/cm2 and the 1-sec peak flux measured from T+3.34 sec in the 15-150 keV band is 1.4 +- 0.3 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.43 +- 0.23 (chi squared 50.23 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/671828/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18945 SUBJECT: GRB 160127A: Swift/UVOT Detection DATE: 16/01/27 20:48:49 GMT FROM: Mike Siegel at PSU/Swift MOC M. H. Siegel (PSU) and Amaral-Rogers (U. Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 160127A 82 s after the BAT trigger (Amaral-Rogers et al., GCN Circ. 18938). A fading source consistent with the XRT position (Evans et al. GCN Circ. 18940) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 15:03:55.76 = 225.98234 (deg.) Dec (J2000) = +00:04:22.5 = 0.07291 (deg.) with an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence). Preliminary detections 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 (fc) 82 232 147 17.59 +/- 0.04 white 574 2411 342 18.66 +/- 0.08 white 6837 7037 196 20.85 +/- 0.28 v 624 1942 156 18.46 +/- 0.19 b 550 1174 58 18.58 +/- 0.16 u (fc) 295 545 246 17.25 +/- 0.05 u 698 2362 174 18.31 +/- 0.13 u 6427 19117 1004 20.92 +/- 0.31 w1 674 1124 58 17.87 +/- 0.20 m2 824 1966 117 19.07 +/- 0.32 w2 600 1917 136 19.56 +/- 0.32 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.06 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18946 SUBJECT: GRB 160127A: LCOGT-Sutherland optical upper limit DATE: 16/01/28 05:58:41 GMT FROM: Dong Xu at NAOC/CAS D. Xu (NAOC/CAS), Y.-H. Han (NAOC/CAS, HUST), Y.-D. Hu (IAA-CSIC), Y. Qing (Geneva Observatory) report on behalf of a larger collaboration: We observed the field of GRB 160127A (Amaral-Rogers et al., GCN 18938) using the LCOGT-1m located at the Sutherland, South Africa. Observations started at 01:14:53 UT on 2016-01-28 (i.e., 16.53 hr after the burst) and a series of 120s Sloan r-band frames were obtained. The previously reported afterglow (Amaral-Rogers et al., GCN 18938; Klotz et al., GCN 18939; Cucchiara et al., GCN 18941) is not detected in our stacked image, down to a limiting magnitude of m(r) ~20.5, calibrated with the SDSS field. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18947 SUBJECT: GRB 160127A: VLA Detection DATE: 16/01/29 02:54:28 GMT FROM: Kate Alexander at Harvard K. D. Alexander (Harvard), T. Laskar (NRAO / UC Berkeley), and E. Berger (Harvard) report on behalf of a larger collaboration: We observed GRB 160127A (Amaral-Rogers et al., GCN 18938) at multiple frequencies with the Karl G. Jansky Very Large Array (VLA) beginning 2016 January 28.46 UT (1.09 days after the burst). At a mean frequency of 21.8 GHz, we detect a radio source with a preliminary flux density of ~70 uJy at RA = 15:03:55.773 +/- 0.013 Dec = +00:04:22.07 +/- 0.17 consistent with the enhanced Swift/XRT position (Evans et al., GCN 18940) and the optical position (Cucchiara et al., GCN 18941; Siegel & Amaral-Rogers, GCN 18945). Follow-up observations are planned. We thank the VLA staff for rapidly executing these observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18948 SUBJECT: GRB 160127A: MITSuME Akeno optical upper limits DATE: 16/01/29 08:23:14 GMT FROM: Taketoshi Yoshii at Tokyo Tech Y.Saito, T.Fujiwara, T. Yoshii, Y. Tano, Y. Tachibana, Y.Ono, S.Harita, Y.Muraki, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We searched for the optical counterpart of GRB 160127A (A. Amaral-Rogers et al., GCN Circular #18938) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan. The observation started on 2016-01-27 17:04:39 UT (~8.4 h after the burst). We did not find previously reported afterglow (A. Amaral-Rogers et al., GCN Circular #18938; A. Klotz et al., GCN Circular #18939; A. Cucchiara et al., GCN Circular #18941) in all three bands. We obtained following limits for the magnitudes. T0+[hour] MID-UT T-EXP[sec] g' Rc Ic ----------------------------------------------------------------------------- 10.19 18:54:38 11700 > 20.7 > 20.4 > 19.2 ----------------------------------------------------------------------------- T0+ : Elapsed time after the burst T-EXP: Total Exposure time We used GSC2.3 catalog for flux calibration. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18949 SUBJECT: GRB 160127A: Khureltogot optical observations DATE: 16/01/29 11:37:43 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), S. Schmalz (AIP), A. Volnova (IKI), N. Tungalag (Research Center of Astronomy and Geophysics MAS), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of Swift GRB 160127A (Amaral-Rogers et al., GCN 18938) with ORI-40 telescope of Khureltogot observatory starting on Jan., 27 (UT) 19:32:48. We marginally detect optical afterglow (Amaral-Rogers et al., GCN 18938; Klotz et al., GCN 18939; Cucchiara et al., GCN 18941). Preliminary photometry of the afterglow is following Date UT start t-T0 Filter Exp. OT Err UL(3sigma) (mid, days) (s) 2016-01-27 19:32:48 0.48499 none 90*60 21.0 0.35 21.0 2016-01-27 21:10:18 0.55333 none 89*60 n/d n/d 21.2 Photometry is based on nearby SDSS stars, R magnitude deduced from Lupton's transformations. SDSS_DR9_id R(Lupton) J150358.16+000929.4 16.36 J150406.02+000738.4 16.03 J150341.40+000835.8 15.17 J150334.55+000806.9 16.20 J150334.11+000513.3 17.32 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18950 SUBJECT: GRB 160127A: RATIR Optical Observations DATE: 16/01/29 16:56:34 GMT FROM: Alan M. Watson at Instituto de Astronomia UNAM Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (GSFC/STScI), 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 160127A (Amaral-Rogers et al., GCN Circular 18938) 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 2016/01 29.43 to 2016/01 29.55 UTC (49.72 to 52.43 hours after the BAT trigger), obtaining a total of 1.48 hours exposure in the r, i, and z bands. We no longer detect the optical counterpart reported by Amaral-Rogers et al. (GCN Circular 18938), Klotz et al. (GCN Circular 18939), Cucchiara et al. (GCN Circular 18941), and Siegel et al. (GCN Circular 18945). In comparison with the SDSS DR9 catalog, we obtain the following 3-sigma upper limits: r > 23.15 i > 23.09 z > 20.00 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.