//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11807 SUBJECT: GRB 110319A: Swift detection of a burst DATE: 11/03/19 02:31:37 GMT FROM: Scott Barthelmy at NASA/GSFC A. Melandri (INAF-OAB), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), P. D'Avanzo (INAF-OAB), J. M. Gelbord (PSU), C. Gronwall (PSU), S. T. Holland (CRESST/USRA/GSFC), N. P. M. Kuin (UCL-MSSL), R. Margutti (INAF-OAB), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/IASFPA) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 02:16:41 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 110319A (trigger=449578). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 356.401, -66.017 which is RA(J2000) = 23h 45m 36s Dec(J2000) = -66d 01' 01" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a double-peaked structure with a duration of about ~30 sec. The peak count rate was ~3800 counts/sec (15-350 keV), at ~5 sec after the trigger. The XRT began observing the field at 02:17:37.5 UT, 55.9 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source with an enhanced position: RA, Dec 356.5017, -66.0114 which is equivalent to: RA(J2000) = 23h 46m 0.40s Dec(J2000) = -66d 00' 40.9" with an uncertainty of 2.3 arcseconds (radius, 90% containment). This location is 148 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 consistent with the Galactic value of 2.62 x 10^20 cm^-2 (Kalberla et al. 2005). The initial flux in the 2.5 s image was 1.10e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 66 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7' x 2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.03. Burst Advocate for this burst is A. Melandri (andrea.melandri AT brera.inaf.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/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11808 SUBJECT: GRB 110319A: Enhanced Swift-XRT position DATE: 11/03/19 07:59:32 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 285 s of XRT Photon Counting mode data and 1 UVOT images for GRB 110319A, 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 = 356.50181, -66.01113 which is equivalent to: RA (J2000): 23h 46m 0.43s Dec (J2000): -66d 00' 40.1" 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: 11810 SUBJECT: GRB 110319A: Swift-XRT refined Analysis DATE: 11/03/19 13:59:42 GMT FROM: Andrea Melandri at INAF-OAB A. Melandri, B. Sbarufatti and R. Margutti (INAF-OAB) reports on behalf of the Swift-XRT team: We have analysed 9.9 ks of XRT data for GRB 110319A (Melandri et al. GCN Circ. 11807), from 47 s to 23.4 ks after the BAT trigger. The data comprise 33 s in Windowed Timing (WT) mode (the first 7 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Goad et al. (GCN. Circ 11808). The light curve can be modelled with a series of power-law decays. The initial decay index is alpha=3.7 (+0.6, -0.3). At T+151 s the decay flattens to an alpha of -0.63 (+0.07, -0.65). The light curve breaks again at T+4335 s to a decay with alpha=0.98(+0.11, -0.10). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 3.4 (+0.4, -0.3). The best-fitting absorption column is 2.4 (+0.7, -0.6) x 10^21 cm^-2, in excess of the Galactic value of 2.6 x 10^20 cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index of 2.33 (+0.13, -0.14) and a best-fitting absorption column of 1.16 (+0.32, -0.18) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.3 x 10^-11 (5.0 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.16 (+0.32, -0.18) x 10^21 cm^-2 Galactic foreground: 2.6 x 10^20 cm^-2 Excess significance: 10.8 sigma Photon index: 2.33 (+0.13, -0.14) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00449578. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11811 SUBJECT: GRB 110319A: Swift-BAT refined analysis DATE: 11/03/19 14:28:25 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), A. Melandri (INAF-OAB), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from recent telemetry downlinks, we report further analysis of BAT GRB 110319A (trigger #449578) (Melandri, et al., GCN Circ. 11807). The BAT ground-calculated position is RA, Dec = 356.510, -66.008 deg, which is RA(J2000) = 23h 46m 02.4s Dec(J2000) = -66d 00' 28.7" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The mask-weighted light curve shows two overlapping peaks starting at ~T_zero, peaking at ~T+5 and ~T+13 sec, and ending at ~T+30 sec. T90 (15-350 keV) is 19.3 +- 1.6 sec (estimated error including systematics). The time-averaged spectrum from T-0.3 to T+31.3 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.31 +- 0.43, and Epeak of 21.9 +- 7.0 keV (chi squared 54.2 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 1.4 +- 0.1 x 10^-6 erg/cm2 and the 1-sec peak flux measured from T+13.10 sec in the 15-150 keV band is 2.2 +- 0.2 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.55 +- 0.08 (chi squared 86.5 for 57 d.o.f.). 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/449578/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11812 SUBJECT: GRB 110319A: Swift/UVOT Detection DATE: 11/03/19 15:19:16 GMT FROM: Mike Siegel at PSU/Swift MOC M. H. Siegel (PSU), S. T. Holland (CRESST/USRA/GSFC) and A. Melandri (INAF-OAB) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 110319A 65s after the BAT trigger (Melandri et al, GCN Circ 11807). We identify an optical afterglow near the enchanced XRT position given by Melandri et al. (GCN Circ. 11810). The transient is only detected in the optical filters and shows fading between the first and second orbits. The preliminary UVOT position is: RA (J2000) 23:46:00.69 = 356.50287 (deg) Dec (J2000) -66:00:40.4 = -66.01122 (deg) with an estimated uncertainty of 0.44 arcsec (radius, 90% confidence, statistical + systematic). Preliminary 3-sigma upper limits and magnitudes using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for the exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white (fc) 65 215 147 18.36+-0.07 white 3924 5560 393 20.32+-0.22 v 4336 5971 393 >19.56 b 3719 5355 393 19.51+-0.21 b 11317 11950 615 >20.63 u 277 395 115 18.13+-0.13 u 4950 11310 1081 19.76+-0.18 uvw1 4745 4945 196 >19.72 uvw1 9497 10397 885 >20.58 uvm2 4540 4740 196 >19.64 uvm2 5976 6172 193 >19.69 uvw2 4131 4330 196 >19.91 uvw2 5566 5766 196 >19.91 The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11813 SUBJECT: GRB 110319B found in ground analysis of Swift-BAT data DATE: 11/03/20 02:31:42 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift J. R. Cummings (UMBC/CRESST/NASA-GSFC), D. M. Palmer (Los Alamos), B. Sbarufatti (INAF-OAB/IASFPA), C. Gronwall (PSU) At 19:34:02, during a Swift slew, Fermi GBM detected a burst. The IPN was alerted. In a mosaic image of BAT slew event data a strong source is found at RA, Dec 326.074, -56.773, which is: RA (J2000) 21h 44m 17.8s Dec (J2000) -56d 46m 24s with an estimated uncertainty of 3 arcmin radius (90% confidence). The burst was in the fully-coded field of view from the trigger time to the end of the Swift slew. This position is 60 degrees (2.2 hours) from the Sun. GRB 110319B was a long GRB with a T90 about 18 seconds. The lightcurve as seen by BAT was a single FRED. A Swift TOO is scheduled to begin at 03:10 March 20, 2011. The BA for this burst is B. Sbarufatti (INAF-OAB/IASFPA). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11814 SUBJECT: GRB 110319B: Swift-XRT afterglow candidate. DATE: 11/03/20 12:01:02 GMT FROM: Boris Sbarufatti at INAF-OAB/IASFPA B. Sbarufatti (INAF-OAB/IASFPA) report on behalf of the Swift-XTR team We have analysed 4.9 ks of XRT data for the Swift/BAT-detected burst: GRB110319B (Cummings et al. et al. GCN Circ. 11813), from 27.7 ks to 35.9 ks after the Swift/BAT trigger. The data are entirely in Photon Counting (PC) mode. An X-ray source is detected within the Swift/BAT error circle. Using 2442 s of PC mode data and 2 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 326.09490, -56.78240 which is equivalent to: RA (J2000): 21h 44m 22.77s Dec(J2000): -56d 46' 56.5" with an uncertainty of 2.4 arcsec (radius, 90% confidence). This position is 53 arcsec from the Swift/BAT position. The source has a mean count rate of 9.4e-03 ct/sec; we cannot determine at the present time whether it is fading. This circular is an official product of the Swift XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11815 SUBJECT: GRB 110319B: GROND upper limits DATE: 11/03/20 15:19:22 GMT FROM: Jochen Greiner at MPI A. Updike (GSFC), J. Greiner, T. Kruehler, F. Schrey (all MPE Garching), A. Nicuesa Guelbenzu and S. Klose (both TLS Tautenburg) report on behalf of the GROND team. We observed the field of GRB 110319B (GBM trigger 322256044 at 19:34:02 UT; Swift slew source, Cummings et al., GCN #11813) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPI/ESO telescope at La Silla Observatory (Chile). Observation started at 08:24 UT, which is 12.9 h after the trigger, and were obtained under clear skies with an airmass of around 2.0 and seeing of 1.6". In stacked images with a total integration time of 25 min in g'r'i'z and 20 min in JHK (mid-time 9:12 UT), we do not detect a source in the 2.4" XRT error circle of the X-ray counterpart candidate (Sbarufatti et al., GCN #11814) to the following 3-sigma upper limits (AB system): g' > 23.1 r' > 23.2 i' > 23.2 z' > 23.2 J > 21.1 H > 20.5 These magnitudes are calibrated against GROND zeropoints and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.03 mag in the direction of the burst (Schlegel et al. 1998). GROND is currently cooling down after hardware maintenance, and hence no proper K band data are available for this burst. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11817 SUBJECT: GRB 110319B: Swift/UVOT Upper Limits DATE: 11/03/21 21:07:01 GMT FROM: Frank Marshall at GSFC F.E. Marshall (NASA/GSFC) and B. Sbarufatti (INAF-OAB/IASFPA) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 110319B 27685 s after the Fermi/GBM trigger (Cummings et al., GCN Circ. 11813). No optical afterglow consistent with the XRT position (Sbarufatti, GCN Circ. 11814) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for the initial exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 28512 35117 1570 >21.8 v 29340 35964 1678 >20.0 u 27685 34323 1597 >20.8 The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11818 SUBJECT: GRB 110319B BAT refined analysis DATE: 11/03/22 15:38:58 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift D. M. Palmer (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), A. Melandri (INAF-OAB), T. Sakamoto (GSFC/UMBC), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-48 to T+52 sec, we report further analysis of GRB 110319B (Cummings, et al., GCN Circ. 11813). The refined BAT position is RA, Dec = 326.088, -56.774 deg, which is RA(J2000) = 21h 44m 21.1s Dec(J2000) = -56d 46m 26s with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). This position is 33 arcsec from the XRT position of the candidate afterglow. The partial coding was 100%. The mask-weighted light curve shows a single FRED peak starting at ~T-3 sec, peaking at ~T0, and ending at ~T+20 sec. T90 (15-350 keV) is 14.5 +- 2 sec (estimated error including systematics). The time-averaged spectrum from T-3.5 to T+16.5 sec is best fit by a simple power law. This fit gives a photon index 1.39 +- 0.05. For this model the total fluence in the 15-150 keV band is 1.0 +- 0.1 x 10-6 erg/cm2 and the 1-sec peak flux measured from T0 sec in the 15-150 keV band is 1.25 +- 0.15 ph/cm2/sec. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11820 SUBJECT: GRB 110319B Swift-XRT afterglow confirmation DATE: 11/03/24 16:31:02 GMT FROM: Boris Sbarufatti at INAF-OAB/IASFPA B. Sbarufatti (INAF-OAB/IASFPA) reports on behalf of the Swift-XRT team: Swift performed a second target of opportunity observation of GRB 110319B on March 23, 2011. The XRT began observing the field at 2011-03-23 17:57:33 UT, that is T+340 ks ( 3.9 days) (Cummings, GCN Circ. 11813). Using 4.9 ks of Photon Counting mode data we find that the source reported previously (Sbarufatti, GCN Circ. 11814) has faded down to a 3-sigma upper limit of 0.002 counts/s. Assuming a power law decay starting from the first source detection the upper limit is consistent with a decay index steeper than alpha = 0.6. The fading nature of the source confirms its afterglow origin. This circular is an official product of the Swift-XRT team.