//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25462 SUBJECT: GRB 190824A: Fermi GBM Final Real-time Localization DATE: 19/08/24 14:56:55 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 14:46:37 UT on 24 Aug 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 190824A (trigger 588350802.674684 / 190824616). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 208.1, Dec = -39.7 (J2000 degrees, equivalent to J2000 13h 52m, -39d 42'), with a statistical uncertainty of 1.5 degrees. The angle from the Fermi LAT boresight is 86.0 degrees. The skymap can be found here: http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190824616/quicklook/glg_skymap_all_bn190824616.png The HEALPix FITS file, including the estimated localization systematic, can be found here: http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190824616/quicklook/glg_healpix_all_bn190824616.fit The GBM light curve can be found here: http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190824616/quicklook/glg_lc_medres34_bn190824616.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25463 SUBJECT: GRB 190824A: Swift detection of a burst DATE: 19/08/24 15:03:25 GMT FROM: David Palmer at LANL V. D'Elia (SSDC), E. Ambrosi (INAF-IASFPA), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), J.D. Gropp (PSU), N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift Observatory Team: At 14:46:39 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 190824A (trigger=922107). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 215.329, -41.902, which is RA(J2000) = 14h 21m 19s Dec(J2000) = -41d 54' 07" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows multiple peaks with a total duration of about 120 sec. The peak count rate was ~3200 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began observing the field at 14:55:24.0 UT, 524.4 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source with an enhanced position: RA, Dec 215.3045, -41.8943 which is equivalent to: RA(J2000) = 14h 21m 13.09s Dec(J2000) = -41d 53' 39.3" with an uncertainty of 2.3 arcseconds (radius, 90% containment). This location is 71 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. No spectrum from the promptly downlinked event data is yet available to determine the column density. UVOT took a finding chart exposure of 150 seconds with the White filter starting 568 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 0.12. Burst Advocate for this burst is V. D'Elia (delia AT ssdc.asi.it). 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/) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25466 SUBJECT: GRB 190824A: Enhanced Swift-XRT position DATE: 19/08/24 20:05:19 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 1213 s of XRT Photon Counting mode data and 2 UVOT images for GRB 190824A, 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 = 215.30490, -41.89382 which is equivalent to: RA (J2000): 14h 21m 13.18s Dec (J2000): -41d 53' 37.8" with an uncertainty of 1.5 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: 25469 SUBJECT: GRB 190824A: Fermi GBM observation DATE: 19/08/24 22:06:37 GMT FROM: Cori Fletcher at USRA C. Fletcher (USRA) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 14:46:37.67 UT on 24 August 2019, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 190824A (trigger 588350802 / 190824616), which was also detected by the Swift/BAT (D'Elia et al. 2019, GCN 25463) The Fermi GBM Final Real-time Localization (GCN 25462) is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 82 degrees. The GBM light curve consists of an initial bright pulse followed by multiple peaks with a duration (T90) of about 109 s (50-300 keV). The time-averaged spectrum from T0-1.024 s to T0+107.52 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.38 +/- 0.06 and the cutoff energy, parameterized as Epeak, is 247 +/- 55 keV The event fluence (10-1000 keV) in this time interval is (1.4 +/- 0.1)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+2.05 s in the 10-1000 keV band is 7.9 +/- 0.4 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25470 SUBJECT: GRB 190824A: Swift-XRT refined Analysis DATE: 19/08/25 03:13:15 GMT FROM: Phil Evans at U of Leicester A. Tohuvavohu (PSU), J.A. Kennea (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , B. Sbarufatti (PSU) and V. D'Elia report on behalf of the Swift-XRT team: We have analysed 6.1 ks of XRT data for GRB 190824A (D'Elia et al. GCN Circ. 25463), from 524 s to 34.2 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN Circ. 25466). The light curve can be modelled with a power-law decay with a decay index of alpha=0.64 (+/-0.04). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.19 (+0.22, -0.21). The best-fitting absorption column is 1.29 (+0.25, -0.22) 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 4.7 x 10^-11 (1.1 x 10^-10) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.29 (+0.25, -0.22) x 10^22 cm^-2 Galactic foreground: 1.0 x 10^21 cm^-2 Excess significance: 8.9 sigma Photon index: 2.19 (+0.22, -0.21) If the light curve continues to decay with a power-law decay index of 0.64, the count rate at T+24 hours will be 0.030 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.4 x 10^-12 (3.3 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/00922107. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25479 SUBJECT: GRB 190824A: Swift/UVOT Upper Limits DATE: 19/08/26 12:55:49 GMT FROM: Kira Simpson at PSU GRB 190824A: Swift/UVOT Upper Limits K. K. Simpson (PSU) and V. D'Elia (SSDC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 190824A 568 s after the BAT trigger (D'Elia et al., GCN Circ. 25463). No optical afterglow consistent with the XRT position (Osborne et al., GCN Circ. 25466) 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 568 718 147 >19.9 white 568 1721 389 >19.9 v 1058 6747 196 >17.8 b 799 1697 97 >18.9 u 774 1672 97 >19.3 w1 750 1647 97 >18.4 m2 725 1622 97 >19.6 w2 849 1742 74 >18.7 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.12 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25482 SUBJECT: GRB 190824A, Swift-BAT refined analysis DATE: 19/08/26 20:50:27 GMT FROM: Hans Krimm at NSF/NASA-GSFC J. R. Cummings (CPI) S. D. Barthelmy (GSFC), V. D'Elia (SSDC), H. A. Krimm (NSF), 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-230 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 190824A (trigger #922107) (D'Elia, et al., GCN Circ. 25463). The BAT ground-calculated position is RA, Dec = 215.323, -41.900 deg which is RA(J2000) = 14h 21m 17.6s Dec(J2000) = -41d 53' 59.5" with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 28%. The mask-weighted light curve shows three main peaks, each with underlying substructure. The first peak is from ~T-80 sec to T-60 sec. The second, largest, peak is from ~T-10 sec to T+50 sec, and the third peak is from ~T+85 sec to T+110 sec. T90 (15-350 keV) is 169.4 +- 5.9 sec (estimated error including systematics). The time-averaged spectrum from T-71.9 to T+114.6 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.62 +- 0.08. The fluence in the 15-150 keV band is 8.5 +- 0.4 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+0.12 sec in the 15-150 keV band is 5.0 +- 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/922107/BA/