//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21016 SUBJECT: GRB 170419B: Swift detection of a burst DATE: 17/04/19 21:59:49 GMT FROM: Scott Barthelmy at NASA/GSFC A. Cholden-Brown (PSU), S. D. Barthelmy (GSFC), C. Gronwall (PSU), N. P. M. Kuin (UCL-MSSL), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 21:33:46 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 170419B (trigger=748947). Swift did not slew due to Sun constraint. The BAT on-board calculated location is RA, Dec 60.498, -15.143, which is RA(J2000) = 04h 01m 59s Dec(J2000) = -15d 08' 32" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single with a duration of about 10 sec. The peak count rate was ~3000 counts/sec (15-350 keV), at ~3 sec after the trigger. Due to a Sun observing constraint, Swift cannot slew to the BAT position until 05:29 UT on 2017 June 19. There will thus be no XRT or UVOT data for this trigger before this time. Burst Advocate for this burst is A. Cholden-Brown (aaronb 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: 21019 SUBJECT: GRB 170419B: Fermi GBM observation DATE: 17/04/20 09:08:01 GMT FROM: Andreas von Kienlin at MPE P. Veres and C. Meegan (both UAH) report on behalf of the Fermi GBM Team: "At 21:33:46.807 UT on 19 April 2016, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 170419B (trigger 514330431 / 170419898). which was also detected by the Swift/BAT (Cholden-Brown et al., GCN 21016). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 41 degrees. The GBM light curve shows a single pulse with a duration (T90) of about 24 s (50-300 keV). The time-averaged spectrum from T0-0.5 s to T0+5.1 s is best fit by a Band function with Epeak = 116 +/- 19 keV, alpha = -0.03 +/- 0.29, and beta = -2.07 +/- 0.15. The event fluence (10-1000 keV) in this time interval is (2.4 +/- 0.2)E-6 erg/cm^2. The 1-sec peak photon flux measured starting from T0+1.2 s in the 10-1000 keV band is 3.8 +/- 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: 21024 SUBJECT: GRB 170419B: Zadko observatory - Gingin optical observations DATE: 17/04/20 14:19:03 GMT FROM: Alain Klotz at IRAP-CNRS-OMP A. Klotz, D. Turpin (IRAP-CNRS-OMP), D. Macpherson (UWA/ICRAR), D. Coward (UWA), M. Boer, (UNS-CNRS-OCA), Gendre B. (UVI - Etelman Obs.), A. Williams (PO-UWA), R. Martin (PO-UWA) report: We imaged the field of GRB 170419B detected by SWIFT (trigger 748947) with the Zadko robotic telescope (D=100cm) located at the observatory - Gingin, Australia. The observations started 13.3h after the GRB trigger. The elevation of the field decreased from 31 degrees above horizon and weather conditions were good. We co-added a series of exposures but we did not find any optical transcient in the BAT error box provided by Cholden-Brown et al. (GCNC 21016): t0+13.3h to t0+13.5h : Rlim = 19.2 Magnitudes were estimated with the nearby NOMAD1 stars and are not corrected for galactic dust extinction. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 21025 SUBJECT: GRB 170419B, Swift-BAT refined analysis DATE: 17/04/20 17:02:25 GMT FROM: Amy Lien at GSFC T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC), A. Cholden-Brown (PSU), J. R. Cummings (CPI), N. Gehrels (GSFC), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU) (i.e. the Swift-BAT team): Using the data set from T-240 to T+262 sec from the recent telemetry downlink, we report further analysis of BAT GRB 170419B (trigger #748947) (Cholden-Brown et al., GCN Circ. 21016). The BAT ground-calculated position is RA, Dec = 60.494, -15.121 deg which is RA(J2000) = 04h 01m 58.5s Dec(J2000) = -15d 07' 14.3" with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 52%. The mask-weighted light curve shows a single-pulse structure that starts at ~ T0 and peaks at ~T+2. The major part of the pulse ends at ~T+10 s, and the weaker tail emission lasts till ~T+90 s. T90 (15-350 keV) is 77.2 +- 9.8 sec (estimated error including systematics). The time-averaged spectrum from T+0.3 to T+88.0 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.47 +- 0.13. The fluence in the 15-150 keV band is 1.9 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+1.98 sec in the 15-150 keV band is 2.4 +- 0.2 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/748947/BA/