//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16938 SUBJECT: GRB 141022A: Swift detection of a burst DATE: 14/10/22 01:48:24 GMT FROM: David Palmer at LANL A. Vargas (PSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. A. Kennea (PSU), V. Mangano (PSU), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU) and T. N. Ukwatta (LANL) report on behalf of the Swift Team: At 01:27:42 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 141022A (trigger=616061). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 241.901, -72.129 which is RA(J2000) = 16h 07m 36s Dec(J2000) = -72d 07' 44" 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 ~1000 counts/sec (15-350 keV), at ~8 sec after the trigger. The XRT began observing the field at 01:29:57.6 UT, 134.9 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 241.8698, -72.1255 which is equivalent to: RA(J2000) = 16h 07m 28.75s Dec(J2000) = -72d 07' 31.7" with an uncertainty of 2.2 arcseconds (radius, 90% containment). This location is 36 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 in excess of the Galactic value (1.04 x 10^21 cm^-2, Willingale et al. 2013), with an excess column of 7.9 (+6.17/-4.49) x 10^21 cm^-2 (90% confidence). UVOT took a finding chart exposure of 250 seconds with the U filter starting 135 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 19.2 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the region. No correction has been made for the expected extinction corresponding to E(B-V) of 0.10. Burst Advocate for this burst is A. Vargas (avargas AT swift.psu.edu). 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: 16939 SUBJECT: GRB 141022A: GROND Detection of a possible Optical Afterglow Candidate DATE: 14/10/22 06:18:29 GMT FROM: Jochen Greiner at MPI D.A. Kann (TLS Tautenburg), T. Schweyer, J. F. Graham, J. Greiner (all MPE Garching) report on behalf of the GROND team: We observed the field of GRB 141022A (Swift trigger 616061; Vargas et al., GCN #16938) 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 01:39 UT on October 22nd, approximately 20 min after the GRB trigger. They were performed on a setting target at high airmass (~2.7) until reaching the pointing limit. Despite a crowed field we find only a single object in the 2.2" Swift-XRT enhanced error circle reported by Vargas et al., GCN #16938) at RA (J2000.0) = 16h 07m 28.82s DEC (J2000.0) = -72d 07' 29.6" (error of 0".5) but cannot ascertain variability in images centered 875 sec and 2095 sec after the trigger, and note the possibility of a chance coincidence given the density of objects in the field. We intended subsequent observations to determine variability. Based on a 16.5 min sequence of exposures, we estimate preliminary magnitudes and limits (all in AB system) of: g' = 23.6 +/- 0.2 mag r' = 22.2 +/- 0.1 mag i' = 21.6 +/- 0.1 mag z' = 22.0 +/- 0.2 mag J > 20.9 mag H > 20.3 mag K > 19.8 mag Given magnitudes are calibrated against GROND zeropoints and 2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.1 mag in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16941 SUBJECT: GRB 141022A: Swift-XRT refined Analysis DATE: 14/10/22 13:48:04 GMT FROM: Phil Evans at U of Leicester P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), M. de Pasquale (INAF-IASFPA), M.C. Stroh (PSU), D.N. Burrows (PSU), J.A. Kennea (PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), B.P. Gompertz (U. Leicester) and A. Vargas report on behalf of the Swift-XRT team: We have analysed 10 ks of XRT data for GRB 141022A (Vargas et al. GCN Circ. 16938), from 144 s to 25.5 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The best available XRT position (using the promptly downlinked event data, the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue) is RA, Dec = 241.8696, -72.1254 which is equivalent to: RA (J2000): 16 07 28.70 Dec(J2000): -72 07 31.4 with an uncertainty of 2.1 arcsec (radius, 90% confidence). The light curve can be modelled with a power-law decay with a decay index of alpha=1.21 (+/-0.08). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.5 (+0.5, -0.4). The best-fitting absorption column is 1.1 (+0.5, -0.4) x 10^22 cm^-2, in excess of 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 3.9 x 10^-11 (1.2 x 10^-10) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.1 (+0.5, -0.4) x 10^22 cm^-2 Galactic foreground: 1.0 x 10^21 cm^-2 Excess significance: 4.5 sigma Photon index: 2.5 (+0.5, -0.4) If the light curve continues to decay with a power-law decay index of 1.21, the count rate at T+24 hours will be 2.7 x 10^-4 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.0 x 10^-14 (3.3 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/00616061. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16942 SUBJECT: GRB 141022A: Swift-BAT refined analysis DATE: 14/10/22 18:31:58 GMT FROM: Tilan Ukwatta at MSU T. Sakamoto (AGU), 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 (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (LANL), A. Vargas (PSU) (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 141022A (trigger #616061) (Vargas, et al., GCN Circ. 16938). The BAT ground-calculated position is RA, Dec = 241.930, -72.152 deg which is RA(J2000) = 16h 07m 43.1s Dec(J2000) = -72d 09' 06.7" with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 39%. The mask-weighted light curve shows a weak episode starting at ~T-1.0 sec, and ending around T+10 sec. The burst location came into the BAT FOV around ~T-140 sec. T90 (15-350 keV) is 8.72 +- 1.56 sec (estimated error including systematics). The time-averaged spectrum from T-0.38 to T+9.17 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.31 +- 0.27. The fluence in the 15-150 keV band is 4.8 +- 0.7 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T+6.20 sec in the 15-150 keV band is 0.9 +- 0.3 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/616061/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16944 SUBJECT: GRB 141022A: Swift/UVOT Upper Limits DATE: 14/10/22 20:09:48 GMT FROM: Mike Siegel at PSU/Swift MOC M. H. Siegel (PSU) and A. Vargas (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 141022A 136 s after the BAT trigger (Vargas et al., GCN Circ. 16938). No optical afterglow consistent with the optical position (Kann et al. GCN Circ. 16939) 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 u (fc) 136 386 246 >20.2 v 443 1997 194 >19.9 b 392 1946 214 >20.6 u 136 1921 568 >20.7 uvw1 493 1895 175 >20.7 uvm2 468 2011 185 >20.5 uvw2 418 1973 194 >20.5 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.10 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16946 SUBJECT: GRB141022A: Fermi GBM Detection DATE: 14/10/23 19:54:27 GMT FROM: Matthew Stanbro at UAH/Fermi Matthew Stanbro (UAH) reports on behalf of the Fermi GBM Team: "At 01:27:48.52 UT on 22 October 2014, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 141022A (trigger 141022061 / 141022061) which was also detected by Swift BAT (Vargas et al. 2014, GCN 16938). The GBM on-ground location, using the Fermi GBM trigger data, is consistent with Swift's location. The GBM light curve shows a long burst, consisting of one main episode, with a total duration (T90) of about 11.5 s (50-300 keV). The time-averaged spectrum from T0-6.1 s to T0+6.1 s is well fit by a power law function with an exponential high-energy cutoff. The power law index is -0.8 +/- 0.3 and the cutoff energy, parameterized as Epeak, is 231.5 +/- 71.1 keV. The event fluence (10-1000 keV) in this time interval is (1.2 +/- 0.2)E-06 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0-5.696 s in the 10-1000 keV band is 1.1 +/- 0.2 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17023 SUBJECT: GRB 141022A: Skynet PROMPT-CTIO Observations DATE: 14/11/03 13:24:59 GMT FROM: Adam S. Trotter at UNC-Chapel Hill/PROMPT/Skynet A. Trotter, J. Haislip, D. Reichart, A. Aji, R. Beauchemin, T. Berger, A. Dow, A. Foster, N. Frank, M. Hinckle, K. Ivarsen, A. LaCluyze, M. Maples, J. Moore, M. Nysewander, C. Salemi, L. Zbinden, and J. A. Crain report: Skynet observed the Swift BAT/XRT localization of GRB 141022A (Vargas et al., GCN 16938, Swift trigger=616061) with one 24" telescope (PROMPT 8; I band) and two 16" telescopes (PROMPT 1,5; V,I bands) of the PROMPT array at CTIO, Chile. Starting at 2014-10-22 01:29:40 UT and continuing until 02:50 UT (t=2m-83m post-trigger), Skynet took a total of 126 exposures ranging from 10s-160s each. We stacked subsets of these images to maximize the S/N ratio, and detected no optical source in either band at the OT position reported by GROND (Kann et al., GCN 16939). Our 3-sigma limiting magnitudes are: ================================== tmid scope expos fil limit ================================== 50m PROMPT1 25x160s V >21.2 50m PROMPT5 24x160s I >20.6 45m PROMPT8 46x80s I >20.3 ================================== Magnitudes are in the Vega System, calibrated to 3 APASS stars in the field. Magnitudes have not been corrected for line-of-sight Milky Way dust extinction, with expected E(B-V)=0.09 (Schlafly & Finkbeiner 2011). No further Skynet observations are scheduled. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17065 SUBJECT: GRB 141022A: TAROT La Silla observatory optical observations DATE: 14/11/13 00:35:18 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 141022A detected by SWIFT (trigger 616061) with the TAROT robotic telescope (D=25cm) located at the European Southern Observatory, La Silla observatory, Chile. The observations started 71s after the GRB trigger (16s after the notice). The elevation of the field decreased from 24 degrees above horizon and weather conditions were excellent. 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+71s to t0+131s : Rlim = 16.4 The second image is 30.0s exposure in tracking mode: t0+145s to t0+175s : Rlim = 17.5 Later TAROT images (until 1800s) do not show any afterglow at Rlim = 17.5 Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction.