//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20462 SUBJECT: GRB 170115A: Swift detection of a burst DATE: 17/01/15 21:15:39 GMT FROM: David Palmer at LANL K. L. Page (U Leicester), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), A. Cholden-Brown (PSU), C. Gronwall (PSU), J. A. Kennea (PSU), H. A. Krimm (CRESST/NSF/USRA), F. E. Marshall (NASA/GSFC) and D. M. Palmer (LANL) report on behalf of the Swift Team: At 20:50:08 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 170115A (trigger=733103). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 332.154, +13.781 which is RA(J2000) = 22h 08m 37s Dec(J2000) = +13d 46' 51" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve is only immediately available until T+8 seconds due to a telemetry gap, showing a rise to a maximum rate of ~800 counts/s at the end of that period. The XRT began observing the field at 20:51:39.5 UT, 91.5 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 332.1390, 13.7283 which is equivalent to: RA(J2000) = +22h 08m 33.36s Dec(J2000) = +13d 43' 41.9" with an uncertainty of 6.3 arcseconds (radius, 90% containment). This location is 196 arcseconds from the BAT onboard position, outside the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 5.14e-10 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 99 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 0.07. Burst Advocate for this burst is K. L. Page (klp5 AT leicester.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: 20465 SUBJECT: GRB 170115A: Enhanced Swift-XRT position DATE: 17/01/16 03:35:10 GMT FROM: Phil Evans at U of Leicester J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team. Using 615 s of XRT Photon Counting mode data and 1 UVOT images for GRB 170115A, 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 = 332.13844, +13.72836 which is equivalent to: RA (J2000): 22h 08m 33.23s Dec (J2000): +13d 43' 42.1" with an uncertainty of 3.7 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: 20470 SUBJECT: GRB 170115A: Swift-XRT refined Analysis DATE: 17/01/16 15:12:26 GMT FROM: Kim Page at U.of Leicester K.L. Page and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: We have analysed 3.9 ks of XRT data for GRB 170115A, from 82 s to 40.4 ks after the BAT trigger. The data comprise 224 s in Windowed Timing (WT) mode (the first 7 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The light curve can be modelled with a power-law decay with a decay index of alpha=1.54 (+0.06, -0.05). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.22 (+0.17, -0.16). The best-fitting absorption column is 1.3 (+0.5, -0.4) x 10^21 cm^-2, in excess of the Galactic value of 6.1 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 2.9 x 10^-11 (4.0 x 10^-11) erg cm^-2 count^-1. A summary of the WT-mode spectrum is thus: Total column: 1.3 (+0.5, -0.4) x 10^21 cm^-2 Galactic foreground: 6.1 x 10^20 cm^-2 Excess significance: 2.6 sigma Photon index: 2.22 (+0.17, -0.16) If the light curve continues to decay with a power-law decay index of 1.54, the count rate at T+24 hours will be 4.1 x 10^-4 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.2 x 10^-14 (1.7 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/00733103. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20471 SUBJECT: GRB 170115A: Swift-BAT refined analysis DATE: 17/01/16 19:22:36 GMT FROM: Hans Krimm at NSF/NASA-GSFC D. M. Palmer (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), N. Gehrels (GSFC), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), K. L. Page (U Leicester), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-240 to T+450 sec from the recent telemetry downlink, we report further analysis of BAT GRB 170115A (trigger #733103) (Page, et al., GCN Circ. 20462). The BAT ground-calculated position is RA, Dec = 332.145, 13.750 deg which is RA(J2000) = 22h 08m 34.9s Dec(J2000) = +13d 45' 01.6" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The mask-weighted light curve shows a single FRED-shaped peak, starting at T+0, peaking at around T+10 sec and decaying to background by around T+50 sec. The spacecraft entered the SAA at around T+400 seconds, so there is no data after this time. T90 (15-350 keV) is 48.0 +- 22.6 sec (estimated error including systematics). The time-averaged spectrum from T-7.6 to T+40.4 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.45 +- 0.25. The fluence in the 15-150 keV band is 4.7 +- 0.8 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+15.94 sec in the 15-150 keV band is 0.2 +- 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/733103/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20478 SUBJECT: GRB 170115A: Swift/UVOT Upper Limits DATE: 17/01/17 16:39:49 GMT FROM: Mike Siegel at PSU/Swift MOC M. H. Siegel (PSU) and K. L. Page (U. Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 170115A 100 s after the BAT trigger (Page et al., GCN Circ. 20462). No optical afterglow consistent with the enhanced XRT position (Osborne et al. GCN Circ. 20465) 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) 100 250 147 >20.40 white 4804 6335 291 >20.66 v 5214 35195 816 >19.67 b 4599 40415 838 >20.68 u (fc) 260 328 67 >18.98 u 5829 6029 196 >19.65 uvw1 5624 5824 196 >19.32 uvm2 5419 5619 196 >19.37 uvw2 5009 11435 992 >20.69 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.07 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20479 SUBJECT: GRB 170115A : AbAO optical upper limit DATE: 17/01/17 17:16:40 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), A. Pozanenko (IKI), R. Inasaridze (AbAO), A. Volnova (IKI), V. Ayvazian (AbAO), O.Kvaratskhelia (AbAO), G. Inasaridze (AbAO), I. Molotov (KIAM), report on behalf of larger GRB follow-up collaboration: We observed the field of the GRB 170115A (Page et al., GCN Circ. 20462) with AS-32 (0.7m) telescope of Abastumani Observatory on Jan., 16 (UT) 14:57:24. We obtained several unfiltered images of the field. No source is found within enhanced XRT position (Osborne et al. GCN Circ. 20465). Preliminary photometry of the field is following Date UT start t-T0 Filter Exp. OT Err UpLim (3 sigma) (mid, days) (s) 2017-01-16 14:57:24 0.78450 CR 49*60 n/d n/d 22.5 Photometry is based on nearby SDSS_DR9 stars SDSS_DR9_id R(Lupton) J220832.66+134330.8 18.50 J220831.22+134259.5 18.59 J220831.94+134225.7 18.57 J220847.68+134539.9 16.60 J220833.30+133952.6 16.32 J220835.19+134539.0 17.66 J220837.56+134537.8 15.86 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 20529 SUBJECT: GRB 170115A: 15 GHz upper limits from AMI DATE: 17/01/26 11:30:40 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 170115A (Page et al., GCN 20462) 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 Jan 16.42, Jan 17.59, Jan 18.67 and Jan 23.51 (UT) do not reveal any radio source at the XRT location (Osborne et al., GCN 20465), with 3sigma upper limits of 300 uJy, 78 uJy, 72 uJy and 81 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/.