//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24785 SUBJECT: GRB 190611A: Swift detection of a burst DATE: 19/06/11 18:02:03 GMT FROM: David Palmer at LANL V. D'Elia (SSDC), J.D. Gropp (PSU), N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), M. J. Moss (GWU), D. M. Palmer (LANL), B. Sbarufatti (PSU), M. H. Siegel (PSU) and A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift Observatory Team: At 17:49:01 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 190611A (trigger=907950). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 324.769, -56.082 which is RA(J2000) = 21h 39m 05s Dec(J2000) = -56d 04' 54" 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 ~900 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began observing the field at 17:50:55.4 UT, 113.5 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source located at RA, Dec 324.72043, -56.07370 which is equivalent to: RA(J2000) = 21h 38m 52.90s Dec(J2000) = -56d 04' 25.3" with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 102 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. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (3.25 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 4.3 (+3.64/-3.06) x 10^21 cm^-2 (90% confidence). UVOT took a finding chart exposure of 150 seconds with the White filter starting 116 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. 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: 24786 SUBJECT: GRB 190611A: Enhanced Swift-XRT position DATE: 19/06/11 20:43:25 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 772 s of XRT Photon Counting mode data and 2 UVOT images for GRB 190611A, 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 = 324.72268, -56.07426 which is equivalent to: RA (J2000): 21h 38m 53.44s Dec (J2000): -56d 04' 27.3" 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: 24790 SUBJECT: GRB 190611A, Swift-BAT refined analysis DATE: 19/06/12 14:08:05 GMT FROM: Amy Lien at GSFC T. Sakamoto (AGU), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), V. D'Elia (SSDC), H. A. Krimm (NSF), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (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 190611A (trigger #907950) (D'Elia et al., GCN Circ. 24785). The BAT ground-calculated position is RA, Dec = 324.689, -56.070 deg which is RA(J2000) = 21h 38m 45.3s Dec(J2000) = -56d 04' 12.6" with an uncertainty of 3.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 64%. The mask-weighted light curve shows a single-peaked structure that starts and peaks at ~T0, and ends at ~T+40 s. T90 (15-350 keV) is 41.8 +- 30.6 sec (estimated error including systematics). The time-averaged spectrum from T-0.9 to T+63.8 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.88 +- 0.54. The fluence in the 15-150 keV band is 4.6 +- 1.6 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.54 sec in the 15-150 keV band is 0.9 +- 0.3 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/907950/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24791 SUBJECT: GRB 190611A: Optical observations from VLT/FORS2 DATE: 19/06/12 14:23:34 GMT FROM: Antonio de Ugarte Postigo at IAA-CSIC R. Sanchez-Ramirez (INAF-IAPS), L. Izzo (HETH/IAA-CSIC), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), D. B. Malesani (DTU Space), D. A. Kann (HETH/IAA-CSIC) report on behalf of the Stargate collaboration: We observed the field of GRB 190611A (D’Elia et al. GCN 24785) with FORS2, mounted on UT1 (Antu) of ESO VLT (Paranal observatory). Two V-band images were obtained in search of the possible afterglow, at a mean epoch of 12 June 08:10:32 UT (14.36 hr after the burst). In the combined exposure of 180s, no new source was detected within the enhanced XRT error circle (Goad et al. GCN 24786) down to a 3-sigma limit of V(AB) = 24.0 mag. Photometric calibration was performed with respect to field stars from the NOMAD catalogue. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 24792 SUBJECT: GRB 190611A: Swift/UVOT Upper Limits DATE: 19/06/12 17:31:41 GMT FROM: Kira Simpson at PSU GRB 190611A: 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 190611A 118 s after the BAT trigger (D'Elia et al., GCN Circ. 24785). No optical afterglow consistent with the XRT position (Goad et al., GCN Circ. 24786) RA (J2000): 21h 38m 53.44s Dec (J2000): -56d 04' 27.3" 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 118 268 147 >20.1 u_FC 276 525 246 >19.2 white 118 917 186 >20.0 u 276 525 246 >19.2 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: 24793 SUBJECT: GRB 190611A: Swift-XRT refined Analysis DATE: 19/06/12 18:03:03 GMT FROM: Phil Evans at U of Leicester B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), E. Ambrosi (INAF-IASFPA) , A. D'Ai (INAF-IASFPA), A. Tohuvavohu (PSU) and V. D'Elia report on behalf of the Swift-XRT team: We have analysed 4.7 ks of XRT data for GRB 190611A (D'Elia et al. GCN Circ. 24785), from 117 s to 22.2 ks after the BAT trigger. The data comprise 15 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. 24786). The light curve can be modelled with a power-law decay with a decay index of alpha=0.93 (+0.09, -0.08). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.48 (+0.24, -0.22). The best-fitting absorption column is 8.5 (+8.2, -5.2) x 10^20 cm^-2, consistent with the Galactic value of 3.2 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 4.5 x 10^-11 (4.9 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 8.5 (+8.2, -5.2) x 10^20 cm^-2 Galactic foreground: 3.2 x 10^20 cm^-2 Excess significance: <1.6 sigma Photon index: 1.48 (+0.24, -0.22) If the light curve continues to decay with a power-law decay index of 0.93, the count rate at T+24 hours will be 2.5 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x 10^-13 (1.2 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/00907950. This circular is an official product of the Swift-XRT team.