//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28043 SUBJECT: GRB 200630A: Swift detection of a burst DATE: 20/06/30 02:09:43 GMT FROM: David Palmer at LANL K. L. Page (U Leicester), S. D. Barthelmy (GSFC), J.D. Gropp (PSU), J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), M. J. Moss (GWU) and D. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift Observatory Team: At 01:49:34 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 200630A (trigger=980210). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 91.380, -60.789 which is RA(J2000) = 06h 05m 31s Dec(J2000) = -60d 47' 20" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 10 sec. The peak count rate was ~1600 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 01:50:52.3 UT, 77.8 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 91.3308, -60.7524 which is equivalent to: RA(J2000) = 06h 05m 19.38s Dec(J2000) = -60d 45' 08.6" with an uncertainty of 2.6 arcseconds (radius, 90% containment). This location is 157 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 https://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 4.33 x 10^20 cm^-2 (Willingale et al. 2013). UVOT took a finding chart exposure of 150 seconds with the White filter starting 82 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 none of the XRT error circle. 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 0.04. This burst is consistent with Fermi/GBM trigger number 615174580. 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/) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28044 SUBJECT: GRB 200630A: Enhanced Swift-XRT position DATE: 20/06/30 15:39:12 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 1889 s of XRT Photon Counting mode data and 3 UVOT images for GRB 200630A, 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 = 91.33040, -60.75279 which is equivalent to: RA (J2000): 06h 05m 19.30s Dec (J2000): -60d 45' 10.1" with an uncertainty of 2.0 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: 28046 SUBJECT: GRB 200630A: Fermi GBM detection DATE: 20/06/30 21:14:09 GMT FROM: Rachel Hamburg at UAH R. Hamburg (UAH) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 01:49:35.08 UT on 30 June 2020, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 200630A (trigger 615174580 / 200630076) which was also detected by the Swift/BAT (Page et al. 2020, GCN 28043) and the Swift/XRT (Beardmore et al. 2020, GCN 28044). The Fermi GBM Final Position is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 42 degrees. The GBM light curve shows one main peak with a duration (T90) of about 7 s (50-300 keV). The time-averaged spectrum from T0-1.5 s to T0+3.56 s is best fit by a single power law function with index of -1.51 +/- 0.05. The event fluence (10-1000 keV) in this time interval is (1.41 +/- 0.12)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0-0.19 s in the 10-1000 keV band is 2.9 +/- 0.2 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: 28049 SUBJECT: GRB 200630A: Swift-XRT refined Analysis DATE: 20/07/01 02:09:03 GMT FROM: Phil Evans at U of Leicester A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , M. Capalbi (INAF-IASFPA), D.N. Burrows (PSU), J. D. Gropp (PSU), J.A. Kennea (PSU) and K.L. Page report on behalf of the Swift-XRT team: We have analysed 2.9 ks of XRT data for GRB 200630A (Page et al. GCN Circ. 28043), from 86 s to 7.0 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN Circ. 28044). The light curve can be modelled with a power-law decay with a decay index of alpha=0.66 (+0.27, -0.20). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.7 (+/-0.5). The best-fitting absorption column is 3.7 (+3.4, -2.3) x 10^21 cm^-2, in excess of the Galactic value of 4.3 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 4.6 x 10^-11 (6.1 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 3.7 (+3.4, -2.3) x 10^21 cm^-2 Galactic foreground: 4.3 x 10^20 cm^-2 Excess significance: 2.3 sigma Photon index: 1.7 (+/-0.5) If the light curve continues to decay with a power-law decay index of 0.66, the count rate at T+24 hours will be 1.8 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.2 x 10^-14 (1.1 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/00980210. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28050 SUBJECT: GRB 200630A: Swift/UVOT Upper Limits DATE: 20/07/01 02:15:16 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 200630A 83 s after the BAT trigger (Page et al., GCN Circ. 28043). No optical afterglow consistent with the XRT position (Page et al. GCN Circ. 28043) 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 83 233 147 >19.7 u_FC 295 545 246 >19.8 white 83 1189 353 >20.4 v 624 1239 78 >18.9 b 550 1164 58 >19.6 u 295 5310 433 >20.1 w1 674 5154 253 >20.1 m2 822 4949 232 >20.5 w2 600 1214 78 >20.0 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.04 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28051 SUBJECT: GRB 200630A: Swift-BAT refined analysis DATE: 20/07/01 04:06:52 GMT FROM: Amy Lien at GSFC D. M. Palmer (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), 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-61 to T+242 sec from the recent telemetry downlink, we report further analysis of BAT GRB 200630A (trigger #980210) (Page et al., GCN Circ. 28043). The BAT ground-calculated position is RA, Dec = 91.389, -60.779 deg which is RA(J2000) = 06h 05m 33.3s Dec(J2000) = -60d 46' 44.8" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 70%. The mask-weighted light curve shows a single-pulse structure that starts and peaks at ~T0, and ends at~T+17 s. T90 (15-350 keV) is 14.83 +- 3.63 sec (estimated error including systematics). The time-averaged spectrum from T-0.51 to T+16.64 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.64 +- 0.24. The fluence in the 15-150 keV band is 4.7 +- 0.7 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.06 sec in the 15-150 keV band is 1.4 +- 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/980210/BA/