GRB180823A

This page lists all entries on GRB180823A in GRBweb

Summary IPN Swift GCN 23169 GCN 23170 GCN 23171 GCN 23172 GCN 23173 GCN 23175

Summary table
Variable Value Source
T0 19:04:32 UTC GCN_circulars,Swift Det
ra 210.3558° Swift
decl 14.8925° Swift
pos_error 1.81e-04° Swift
T90 80.3 s Swift
T90_start 19:04:32 UTC Swift
fluence 7.80e-06 erg/cm² Swift
T100 80.3 s
GBM_located False
mjd 58353.79481481481 GCN_circulars,Swift Det
IPN table
GRB_name GRB180823A
ra 210.3500°
decl 14.8833°
pos_error 5.00e-02°
Swift table
GRB_name GRB180823A
t_trigger 19:04:32 UTC
ra 210.3558°
decl 14.8925°
pos_error 1.81e-04°
T90 80.3 s
fluence 7.80e-06 erg/cm²
GCN 23169 table
GRB_name GRB180823A
GCN_number 23169
Detection_method Swift Det
t_trigger 19:04:32 UTC
ra 210.3490°
decl 14.8840°
Circular_text TITLE: GCN CIRCULAR NUMBER: 23169 SUBJECT: GRB 180823A: Swift detection of a burst DATE: 18/08/23 19:31:39 GMT FROM: Aaron Tohuvavohu at PSU/Swift B. Sbarufatti (PSU), H. A. Krimm (NSF/USRA), F. E. Marshall (NASA/GSFC) and A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift Observatory Team: At 19:04:32 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 180823A (trigger=855434). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 210.349, +14.884 which is RA(J2000) = 14h 01m 24s Dec(J2000) = +14d 53' 03" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve, which is superimposed on a declining background, shows a double-peaked structure with a duration of about 40 sec. The peak count rate was ~2000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 19:06:02.2 UT, 89.2 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 210.35630, 14.89029 which is equivalent to: RA(J2000) = 14h 01m 25.51s Dec(J2000) = +14d 53' 25.0" with an uncertainty of 5.4 arcseconds (radius, 90% containment). This location is 34 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. No spectrum from the promptly downlinked event data is yet available to determine the column density. The initial flux in the 2.5 s image was 3.10e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 37 seconds with the White filter starting 379 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 is expected to be about 18.5 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.02. Burst Advocate for this burst is B. Sbarufatti (bxs60 AT 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.)
GCN 23170 table
GRB_name GRB180823A
GCN_number 23170
Detection_method Swift-XRT Det
ra 210.3558°
decl 14.8925°
Circular_text TITLE: GCN CIRCULAR NUMBER: 23170 SUBJECT: GRB 180823A: Enhanced Swift-XRT position DATE: 18/08/24 00:43:22 GMT FROM: Phil Evans at U of Leicester M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team. Using 2364 s of XRT Photon Counting mode data and 7 UVOT images for GRB 180823A, 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 = 210.35583, +14.89245 which is equivalent to: RA (J2000): 14h 01m 25.40s Dec (J2000): +14d 53' 32.8" with an uncertainty of 1.6 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.
GCN 23171 table
GRB_name GRB180823A
GCN_number 23171
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 23171 SUBJECT: GRB 180823A: Swift-XRT refined Analysis DATE: 18/08/24 13:43:15 GMT FROM: Phil Evans at U of Leicester A. Tohuvavohu (PSU), S. J. LaPorte (PSU), S.L. Gibson (U. Leicester), Z. Liu (NAOC / U. Leicester), J.P. Osborne (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), J.A. Kennea (PSU) and B. Sbarufatti report on behalf of the Swift-XRT team: We have analysed 7.7 ks of XRT data for GRB 180823A (Sbarufatti et al. GCN Circ. 23169), from 331 s to 39.4 ks after the BAT trigger. The data comprise 46 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Goad et al. (GCN Circ. 23170). 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 1.99 (+0.19, -0.18). The best-fitting absorption column is 1.2 (+/-0.5) x 10^21 cm^-2, in excess of the Galactic value of 1.2 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 (4.2 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.2 (+/-0.5) x 10^21 cm^-2 Galactic foreground: 1.2 x 10^20 cm^-2 Excess significance: 3.7 sigma Photon index: 1.99 (+0.19, -0.18) 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 0.013 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.3 x 10^-13 (5.3 x 10^-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00855434. This circular is an official product of the Swift-XRT team.
GCN 23172 table
GRB_name GRB180823A
GCN_number 23172
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 23172 SUBJECT: GRB 180823A: RATIR Optical and NIR Observations DATE: 18/08/24 14:46:19 GMT FROM: Nat Butler at Az State U Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki Toy (UMD) report: We observed the field of GRB 180823A (Sbarufatti, et al., GCN 23169) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir from 2018/08 24.14 to 2018/08 24.19 UTC (8.40 to 9.45 hours after the BAT trigger), obtaining a total of 0.40 hours exposure in the r and i bands and 0.29 hours exposure in the Z, Y, J, and H bands. For a source within the Swift-XRT error circle (Evans, et al., GCN 23170), in comparison with the SDSS DR9 and 2MASS catalogs, we obtain the following upper limits (3-sigma): r > 22.20 i > 22.05 Z > 20.84 Y > 19.72 J > 20.45 H > 19.12 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.
GCN 23173 table
GRB_name GRB180823A
GCN_number 23173
Detection_method Swift-UVOT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 23173 SUBJECT: GRB 180823A: Swift/UVOT Upper Limits DATE: 18/08/24 16:26:22 GMT FROM: Sam LaPorte at PSU GRB 180823A: Swift/UVOT Upper Limits S. Sebzda (PSU) and B. Sbarufatti (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 180823A 381 s after the BAT trigger (Sbarufatti et al., GCN Circ. 23169). No optical afterglow consistent with the XRT position (Goad et al. GCN Circ. 23170) 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 initial exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 381 417 36 >19.1 white 381 4476 380 >20.9 v 4686 10356 927 >19.2 b 4071 4271 197 >19.7 u 3866 4066 197 >19.8 m2 10361 10803 435 >19.8 w2 4482 4681 197 >20.0 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel et al. 1998).
GCN 23175 table
GRB_name GRB180823A
GCN_number 23175
Detection_method Swift-BAT Det
ra 210.3580°
decl 14.9010°
Circular_text TITLE: GCN CIRCULAR NUMBER: 23175 SUBJECT: GRB 180823A, Swift-BAT refined analysis DATE: 18/08/25 20:56:53 GMT FROM: Hans Krimm at NSF/NASA-GSFC A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), B. Sbarufatti (PSU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-43 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 180823A (trigger #855434) (Sbarufatti, et al., GCN Circ. 23169). The BAT ground-calculated position is RA, Dec = 210.358, 14.901 deg which is RA(J2000) = 14h 01m 25.9s Dec(J2000) = +14d 54' 03.2" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 92%. The available data starts as the burst is rising, but it appears that it includes the entire burst. The mask-weighted light curve shows a double-peaked structure, starting at ~T-43 seconds, with comparably sized peaks at ~T+5 and ~T+20 sec, and returning to near background by T+70 seconds, with a fainter tail out past T+100 seconds. A spacecraft slew took the burst location out of the BAT field of view around T+450 seconds. T90 (15-350 keV) is 80.3 +- 6.9 sec (estimated error including systematics). The time-averaged spectrum from T-37.5 to T+72.0 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.58 +- 0.05. The fluence in the 15-150 keV band is 7.8 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+18.33 sec in the 15-150 keV band is 2.3 +- 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/855434/BA/