//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12548 SUBJECT: GRB 111109A: Swift detection of a burst DATE: 11/11/09 03:07:17 GMT FROM: David Palmer at LANL C. Pagani (U Leicester), S. D. Barthelmy (GSFC), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/IASFPA), M. H. Siegel (PSU) and T. N. Ukwatta (MSU) report on behalf of the Swift Team: At 02:57:46 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 111109A (trigger=507342). Swift did not slew due an observing constraint. The BAT on-board calculated location is RA, Dec 118.196, -41.599, which is RA(J2000) = 07h 52m 47s Dec(J2000) = -41d 35' 54" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a few peaks with a total duration of about 20 sec. The peak count rate was ~1500 counts/sec (15-350 keV), at ~1 sec after the trigger. Due to an observing constraint, Swift will not slew until T0+49.2 minutes. There will be no XRT or UVOT data until this time. Burst Advocate for this burst is C. Pagani (cp232 AT star.le.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/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12549 SUBJECT: GRB 111109A: Swift-XRT observations DATE: 11/11/09 04:24:11 GMT FROM: Phil Evans at U of Leicester D.N. Burrows (PSU), J.A. Kennea (PSU), M. Perri (ASDC), G. Tagliaferri (INAF-OAB), P.A. Evans (U. Leicester) and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team: The XRT began observing the field of GRB 111109A at 03:49:14.9 UT, 3088.9 seconds after the BAT trigger. No source was detected in 922 s of promptly downlinked data. We are waiting for the full dataset to detect and localise the XRT counterpart. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12550 SUBJECT: GRB 111109A: Enhanced Swift-XRT position DATE: 11/11/09 08:36:22 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 2557 s of XRT Photon Counting mode data and 1 UVOT images for GRB 111109A, 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 = 118.20283, -41.58413 which is equivalent to: RA (J2000): 07h 52m 48.68s Dec (J2000): -41d 35' 02.9" with an uncertainty of 2.4 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: 12551 SUBJECT: GRB 111109A: Swift-BAT refined analysis DATE: 11/11/09 14:14:55 GMT FROM: Scott Barthelmy at NASA/GSFC W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), C. Pagani (U Leicester), 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-240 to T+645 sec from recent telemetry downlinks, we report further analysis of BAT GRB 111109A (trigger #507342) (Pagani, et al., GCN Circ. 12548). The BAT ground-calculated position is RA, Dec = 118.248, -41.588 deg, which is RA(J2000) = 07h 52m 59.5s Dec(J2000) = -41d 35' 18.3" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 91%. The mask-weighted light curve shows a couple overlapping peaks starting at ~T-5 sec, peaking at ~T+2 sec, and ending at ~T+20 sec. There is a hint of possible precursor activity (~2 sigma) at ~T-110 sec. We note that the burst location went out of the BAT FoV at ~T+120 sec (a slew due to an observing constraint). T90 (15-350 keV) is 13.0 +- 3.2 sec (estimated error including systematics). The time-averaged spectrum from T-5.60 to T+8.40 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.86 +- 0.26. The fluence in the 15-150 keV band is 2.4 +- 0.4 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+1.40 sec in the 15-150 keV band is 0.5 +- 0.1 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/507342/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12552 SUBJECT: GRB 111109A: Swift/UVOT Photometry DATE: 11/11/09 20:13:32 GMT FROM: Stephen Holland at USRA/NASA/GSFC/SSC S. T. Holland (CRESST/USRA/GSFC) and C. Pagani (U Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT observed the field of GRB 111109A starting 3074 s after the BAT trigger (Pagani et al., 2011, GCNC 12548). Settled observations started at 3095 s. The USNO-B1.0 source 0484-0114145 is seen in the UVOT-enhanced XRT error circle (Beardmore et al., 2011, GCNC 12550). Our preliminary photometry suggests that this source did not vary during the UVOT observations. We note that the position listed in the GCN/SWIFT_POSITION_NOTICE dated Wed 09 Nov 11 03:56:21 UT is incorrect due to it being inconsistent with the XRT position, and the presence of a nearby high proper motion star. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12553 SUBJECT: GRB 111109A: Swift-XRT refined Analysis DATE: 11/11/09 23:04:22 GMT FROM: Claudio Pagani at U of Leicester C. Pagani (U Leicester) reports on behalf of the Swift-XRT team: We have analysed 10 ks of XRT data for GRB 111109A (Pagani et al. GCN Circ. 12548), from 3.1 ks to 51.8 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 12550). The light curve can be modelled with a power-law decay with a decay index of alpha=0.5 (+/-0.3). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 3.0 (+0.8, -0.7). The best-fitting absorption column is 6.1 (+3.1, -2.9) x 10^21 cm^-2, in excess of the Galactic value of 3.2 x 10^21 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.1 x 10^-11 (1.5 x 10^-10) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 6.1 (+3.1, -2.9) x 10^21 cm^-2 Galactic foreground: 3.2 x 10^21 cm^-2 Excess significance: 3.5 sigma Photon index: 3.0 (+0.8, -0.7) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00507342. This circular is an official product of the Swift-XRT team.