//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12774 SUBJECT: GRB 111229A: Swift detection of a burst DATE: 11/12/29 22:55:19 GMT FROM: Scott Barthelmy at NASA/GSFC A. Y. Lien (NASA/GSFC/ORAU), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), S. Campana (INAF-OAB), P. D'Avanzo (INAF-OAB), N. Gehrels (NASA/GSFC), S. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU), H. A. Krimm (CRESST/GSFC/USRA), V. Mangano (INAF-IASFPA), A. Melandri (INAF-OAB), J. L. Racusin (NASA/GSFC), P. Romano (INAF-IASFPA), E. Troja (NASA/GSFC/ORAU) and B.-B. Zhang (PSU) report on behalf of the Swift Team: At 22:37:52 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 111229A (trigger=510736). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 76.282, -84.723, which is RA(J2000) = 05h 05m 08s Dec(J2000) = -84d 43' 20" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows two or three peaks with a total duration of about 25 sec. The peak count rate was ~1300 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began observing the field at 22:39:15.5 UT, 83.3 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 76.2885, -84.7108 which is equivalent to: RA(J2000) = 05h 05m 09.25s Dec(J2000) = -84d 42' 38.8" with an uncertainty of 2.5 arcseconds (radius, 90% containment). This location is 43 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. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (1.04 x 10^21 cm^-2, Kalberla et al. 2005), with an excess column of 9.2 (+7.65/-5.74) x 10^21 cm^-2 (90% confidence). UVOT took a finding chart exposure of 150 seconds with the White filter starting 87 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image processing failed because of no aspect solution. Results from the list of sources generated on-board are not available at this time. A full analysis will not be possible until the full data set is downlinked. Burst Advocate for this burst is A. Y. Lien (yarleen AT gmail.com). 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: 12775 SUBJECT: GRB 111229A: GROND afterglow candidate DATE: 11/12/30 01:57:34 GMT FROM: Sylvio Klose at TLS Tautenburg A. Nicuesa Guelbenzu, S. Klose, D. A. Kann (all TLS Tautenburg), and J. Greiner (MPE Garching) report on behalf of the GROND team: We observed the field of GRB 111229A (Lien et al., GCN 12774) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2-m MPG/ESO telescope on La Silla. Observations started in twilight, at 00:45 UT on December 30, 2.12 hr after the burst. In the refined XRT error circle (Lien et al., GCN 12774), we detect a new source in all bands which is significantly brighter than the DSS2 limit at RA, DEC (J2000) = 05:05:08.84, -84:42:38.7. At a mean time of December 30, 00:51 UT, in an 8min exposure, we measure the following preliminary magnitudes (AB system): g' = 20.50 +/- 0.04, r' = 19.96 +/- 0.03, i' = 19.74 +/- 0.03, z' = 19.58 +/- 0.03, J = 19.01 +/- 0.11. We propose this source to be the afterglow of GRB 111229A, implying a redshift of less than 3.5. After correcting for a Galactic reddening of 0.18 mag, the SED is best fit with a spectral slope of 0.72 +/- 0.06. Optical data are calibrated against GROND zero points and NIR data against 2MASS field stars. Observations are continuing. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12776 SUBJECT: GRB 111229A: Swift-BAT refined analysis DATE: 11/12/30 02:12:44 GMT FROM: Scott Barthelmy at NASA/GSFC H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), A. Y. Lien (NASA/GSFC/ORAU), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-60 to T+243 sec from the recent telemetry downlink, we report further analysis of BAT GRB 111229A (trigger #510736) (Lien, et al., GCN Circ. 12774). The BAT ground-calculated position is RA, Dec = 76.561, -84.687 deg which is RA(J2000) = 05h 06m 14.5s Dec(J2000) = -84d 41' 14.8" with an uncertainty of 2.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 78%. The mask-weighted light curve shows an initial peak starting at ~T-2 sec, peaking at ~T+1 sec, and returning to baseline at ~T+7 sec. The second weaker peak starts at ~T+15 sec and ends at ~T+22 sec. T90 (15-350 keV) is 25.4 +- 5.0 sec (estimated error including systematics). The time-averaged spectrum from T-0.97 to T+26.15 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.85 +- 0.33. The fluence in the 15-150 keV band is 3.4 +- 0.7 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.12 sec in the 15-150 keV band is 1.0 +- 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/510736/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12777 SUBJECT: GRB 111229A: Gemini-South Redshift DATE: 11/12/30 02:32:04 GMT FROM: Antonino Cucchiara at LBNL A. Cucchiara (UCSC/UCO Lick), A. J. Levan (U. Warwick), and N. Tanvir (U. Leicester) report: On December 30.05 UT (157 minutes after the BAT trigger) we observed the field of GRB 111229A (Lien et al., GCN 12774) using GMOS-South on the Gemini-South 8-m telescope. An optical afterglow is detected at a position reported by Nicuesa Guelbenzu et al. (GCN 12775). Subsequent spectroscopic observation of the optical afterglow of GRB 111229A (range 5900-10080 Angstroms) reveals several absorption features, including FeII2586,2600, MnII2606, MgII2796,2803 and MgII2853 at a common redshift of 1.3805. We therefore suggest this to be the redshift of GRB 111229A. We thank the Gemini staff for performing this observation, in particular Pascale Hibon. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12780 SUBJECT: GRB 111229A: Enhanced Swift-XRT position DATE: 11/12/30 07:20:00 GMT FROM: Phil Evans at U of Leicester J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team. Using 943 s of XRT Photon Counting mode data and 2 UVOT images for GRB 111229A, 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 = 76.28979, -84.71099 which is equivalent to: RA (J2000): 05h 05m 9.55s Dec (J2000): -84d 42' 39.6" 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: 12781 SUBJECT: GRB 111229A: Swift-XRT refined Analysis DATE: 11/12/30 10:55:04 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester), O.M. Littlejohns (U. Leicester), B. Sbarufatti (INAF-OAB/PSU), G. Stratta (ASDC), P. D'Avanzo (INAF-OAB), M.C. Stroh (PSU), D.N. Burrows (PSU), J.A. Kennea (PSU), J.P. Osborne (U. Leicester) and A.Y. Lien report on behalf of the Swift-XRT team: We have analysed 6.7 ks of XRT data for GRB 111229A (Lien et al. GCN Circ. 12774), from 93 s to 22.6 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN. Circ 12780). The late-time light curve (from T0+4.4 ks) can be modelled with a power-law decay with a decay index of alpha=1.54 (+0.14, -0.13). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.06 (+0.17, -0.14). The best-fitting absorption column is 1.9 (+/-0.5) x 10^21 cm^-2, in excess of the Galactic value of 1.0 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 3.7 x 10^-11 (5.5 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.9 (+/-0.5) x 10^21 cm^-2 Galactic foreground: 1.0 x 10^21 cm^-2 Excess significance: 2.7 sigma Photon index: 2.06 (+0.17, -0.14) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00510736. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12782 SUBJECT: GRB 111229A: Faulkes Telescope South observations DATE: 11/12/30 12:16:31 GMT FROM: Cristiano Guidorzi at Ferrara U,Italy C. Guidorzi (U. Ferrara), A. Melandri (INAF-OAB) report on behalf of the LJMU GRB group: The 2-m Faulkes Telescope South observed Swift GRB 111229A (Lien et al. GCN Circ. 12774) on December 30, from 10:08 UT, corresponding to 11.5 hours after the BAT trigger time. We clearly detect the optical afterglow (Nicuesa Guelbenzu et al. GCN Circ 12775; Cucchiara et al. GCN Circ. 12777) in the R filter and marginally in the i' filter with the following magnitude: Mid time from Total Exp Filter Magnitude Limit trigger (hr) (s) -------------------------------------------------------- 11.77 6x300 i' 21.6 +- 0.5 >20.9 12.34 6x300 R 21.4 +- 0.1 -------------------------------------------------------- Magnitudes are calibrated against nearby USNOB-1 stars. Comparing with GROND observations (Nicuesa Guelbenzu et al GCN 12775), we derive an average power-law decay index of about 0.8. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12783 SUBJECT: GRB 111229A: Swift/UVOT Detection DATE: 11/12/30 13:32:12 GMT FROM: Samantha Oates at MSSL S. R. Oates (MSSL-UCL) and A. Y. Lien (NASA/GSFC/ORAU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 111229A 87 s after the BAT trigger (Lien et al., GCN Circ. 12774). A source consistent with the XRT position (Osborne et al., GCN Circ. 12780) and the GROND optical position (Nicuesa Guelbenzu et al., GCN Circ. 12780) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 05:05:08.86 = 76.28692 (deg.) Dec (J2000) = -84:42:39.1 = -84.71085 (deg.) with an estimated uncertainty of 0.55 arc sec. (radius, 90% confidence). Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white (FC) 87 237 147 18.78 +/- 0.10 white 5230 5430 200 20.48 +/- 0.27 v 630 649 20 17.70 +/- 0.49 b 554 574 20 18.75 +/- 0.53 u (FC) 300 549 250 19.03 +/- 0.23 u 4820 5020 200 20.67 +/- 0.53 w1 679 6251 413 >20.4 m2 4410 6046 393 >20.4 w2 779 22585 1597 >21.4 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.18 in the direction of the burst (Schlegel et al. 1998).