//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16831 SUBJECT: GRB 140919A: Swift detection of a burst DATE: 14/09/19 15:38:25 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT M.E. Gropp (PSU), S. B. Cenko (GSFC), C. Gronwall (PSU), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), N. P. M. Kuin (UCL-MSSL), A. Y. Lien (GSFC/UMBC), V. Mangano (PSU), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC), J. L. Racusin (NASA/GSFC) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift Team: At 15:15:15 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 140919A (trigger=613160). The BAT on-board calculated location is RA, Dec 221.556, -32.154 which is RA(J2000) = 14h 46m 13s Dec(J2000) = -32d 09' 14" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multi-peaked structure with a duration of about 100 sec. The peak count rate was ~2000 counts/sec (15-350 keV), at ~1 sec after the trigger. Due to an observing constraint, Swift will not slew until T0+48.2 minutes. There will be no XRT or UVOT data until this time. Burst Advocate for this burst is M.E. Gropp (mgropp742 AT gmail.com). 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: 16832 SUBJECT: GRB 140919A: Swift-XRT observations DATE: 14/09/19 16:36:48 GMT FROM: Phil Evans at U of Leicester M. Perri (ASDC), G. Tagliaferri (INAF-OAB), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), D.N. Burrows (PSU) and J.A. Kennea (PSU) report on behalf of the Swift-XRT team: The XRT began observing the field of GRB 140919A at 16:07:15.9 UT, 3120.4 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 221.53822, -32.17586 which is equivalent to: RA(J2000) = 14h 46m 09.17s Dec(J2000) = -32d 10' 33.1" with an uncertainty of 3.9 arcseconds (radius, 90% containment). This location is 95 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 7.65 x 10^20 cm^-2 (Willingale et al. 2013). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16833 SUBJECT: GRB 140919A: Swift/UVOT observations DATE: 14/09/19 17:22:26 GMT FROM: Samantha Oates at MSSL S. R. Oates (IAA-CSIC, MSSL-UCL) and M.E. Gropp (PSU) report on behalf of the Swift/UVOT team: UVOT took a finding chart exposure of 150 seconds with the White filter starting 3124 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. We note that within the XRT error circle (Perri et al., GCN Circ. 16832) there is a point source which is also observed in the DSS. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. The typical 3-sigma upper limit has been about 19.6mag. The 8'x8' region for the list of sources generated on-board covers 100% of the BAT error circle. The list of sources is typically complete to about 18mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.09. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16834 SUBJECT: GRB 140919A: Enhanced Swift-XRT position DATE: 14/09/19 19:23:43 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 1892 s of XRT Photon Counting mode data and 1 UVOT images for GRB 140919A, 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 = 221.53734, -32.17629 which is equivalent to: RA (J2000): 14h 46m 8.96s Dec (J2000): -32d 10' 34.7" with an uncertainty of 1.8 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: 16835 SUBJECT: GRB 140919A: Fermi GBM observation DATE: 14/09/20 02:54:19 GMT FROM: Veronique Pelassa at UAH V. Pelassa (UAH) and D. Yu (MPE) report on behalf of the Fermi GBM Team: "At 15:15:13.54 UT on 19 September 2014, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 140919A (trigger 432832516 / 140919636), which was also detected by the Swift/BAT (Gropp et al. 2014, GCN 16831). The GBM on-ground location is consistent with the Swift position. The angle of the Swift position from the Fermi LAT boresight is 34.6 degrees. The GBM light curve consists of multiple peaks with a duration (T90) of about 109 s (50-300 keV). The time-averaged spectrum from T0-5.12 s to T0+123.91 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.80 +/- 0.04 and the cutoff energy, parameterized as Epeak, is 103 +/- 18 keV (Castor statistics 1085.8 for 610 d.o.f.). The event fluence (10-1000 keV) in this time interval is (1.20 +/- 0.06)E-05 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+5.248 s in the 10-1000 keV band is 3.6 +/- 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: 16836 SUBJECT: GRB 140919A: GROND afterglow candidate DATE: 14/09/20 03:46:13 GMT FROM: Sebastian Schmidl at TLS Tautenburg S. Schmidl (TLS Tautenburg), J. Bolmer and J. Greiner (both MPE Garching) report on behalf of the GROND team: We observed the field of GRB 140919A (Swift trigger 613160; Gropp et al., GCN #16831) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m MPG telescope at ESO La Silla Observatory (Chile). Observations started at 23:29 UT on 2014-09-19, 8.2 hrs after the GRB trigger. They were performed at an average seeing of 1.7" and at an average airmass of 2.1. We detect a source inside the enhanced 1.5" Swift-XRT error cicle, at RA (J2000.0) = 14:46:08.96 DEC (J2000.0) = -32:10:34.6 with an uncertainty of 0.5" in each coordinate. Based on total exposures of 7.7 minutes in g'r'i'z'and 24.0 minutes in JHK, at a midtime of 9.2 hrs after the burst, we measure the following preliminary magnitudes and upper limits (AB magnitude system): g' = 19.8 +/- 0.1, r' = 19.5 +/- 0.1, i' = 19.4 +/- 0.1, z' = 19.3 +/- 0.1, J = 18.9 +/- 0.1, H = 19.0 +/- 0.2, and K > 18.9. At present we cannot decide if the source is fading. Given magnitudes are calibrated against GROND zeropoints as well as 2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V) = 0.09 mag in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16837 SUBJECT: GRB 140919A: Swift/UVOT Detection DATE: 14/09/20 11:53:48 GMT FROM: Samantha Oates at MSSL S. R. Oates (IAA-CSIC/UCL-MSSL) and M.E. Gropp (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 140919A 3125 s after the BAT trigger (Gropp et al., GCN Circ. 16831). A fading source consistent with the optical and enhanced XRT position (Schmidl et al. GCN Circ. 16836; Beardmore et al., GCN Circ 16834) is detected in the initial UVOT exposures. Initial identification was complicated by the presence of a point source in the DSS close to the optical position. Photometry is therefore also complicated by the presence of this point source. 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) 3125 3275 147 16.62 +/- 0.05 white 45180 45480 295 19.40 +/- 0.11 v 4848 5047 197 17.33 +/- 0.10 b 8834 9134 295 18.34 +/- 0.09 u 5462 5613 148 16.86 +/- 0.07 w1 5258 5458 197 16.98 +/- 0.09 m2 5052 5252 197 17.12 +/- 0.11 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.09 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16838 SUBJECT: GRB 140919A: Swift-XRT refined Analysis DATE: 14/09/20 15:19:03 GMT FROM: Matthew Gropp at PSU/Swift M.E. Gropp (PSU) reports on behalf of the Swift-XRT team: We have analysed 12 ks of XRT data for GRB 140919A (Gropp et al. GCN Circ. 16831), from 3.1 ks to 57.4 ks after the BAT trigger. The data comprise 99 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN Circ. 16834). The light curve can be modelled with a power-law decay with a decay index of alpha=1.00 (+/-0.04). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.05 (+/-0.10). The best-fitting absorption column is 1.54 (+0.30, -0.29) x 10^21 cm^-2, in excess of the Galactic value of 7.6 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 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: 1.54 (+0.30, -0.29) x 10^21 cm^-2 Galactic foreground: 7.6 x 10^20 cm^-2 Excess significance: 4.5 sigma Photon index: 2.05 (+/-0.10) If the light curve continues to decay with a power-law decay index of 1.00, the count rate at T+24 hours will be 0.061 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.0 x 10^-12 (2.7 x 10^-12) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00613160. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 16839 SUBJECT: GRB 140919A, Swift-BAT refined analysis DATE: 14/09/20 21:03:58 GMT FROM: Amy Lien at GSFC T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), M.E. Gropp (PSU), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), J. Tueller (GSFC), (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 140919A (trigger #613160) (Gropp, et al., GCN Circ. 16831). The BAT ground-calculated position is RA, Dec = 221.540, -32.153 deg which is RA(J2000) = 14h 46m 09.5s Dec(J2000) = -32d 09' 11.5" with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 14%. The mask-weighted light curve shows a multi-peaked structure starts at ~ T-1 s and ends at ~T+175 s. The structure includes roughly three peaks at ~T+3 s, ~T+40 s, and ~T+90 s, respectively. T90 (15-350 keV) is 151.3 +- 25.6 sec (estimated error including systematics). The time-averaged spectrum from T-0.7 to T+174.6 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.74 +- 0.12. The fluence in the 15-150 keV band is 5.9 +- 0.4 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+38.97 sec in the 15-150 keV band is 2.0 +- 0.5 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/613160/BA/