//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14115 SUBJECT: GRB 121229A: Swift detection of a burst DATE: 12/12/29 05:15:29 GMT FROM: Mike Siegel at PSU/Swift MOC E. Sonbas (NASA/GSFC/Adiyaman Univ.), V. D'Elia (ASDC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), T. Sakamoto (AGU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 05:00:21 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 121229A (trigger=544347). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 190.100, -50.594 which is RA(J2000) = 12h 40m 24s Dec(J2000) = -50d 35' 37" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). Since this is an image trigger, the BAT light curve does not show any particular structure. The peak count rate was ~1000 counts/sec (15-350 keV), at ~5 sec after the trigger. The XRT began observing the field at 05:02:47.8 UT, 145.9 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 190.09755, -50.59366 which is equivalent to: RA(J2000) = 12h 40m 23.41s Dec(J2000) = -50d 35' 37.2" with an uncertainty of 4.1 arcseconds (radius, 90% containment). This location is 5.7 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 consistent with the Galactic value of 1.35 x 10^21 cm^-2 (Kalberla et al. 2005). The initial flux in the 2.5 s image was 1.21e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 155 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 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 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 0.16. Burst Advocate for this burst is E. Sonbas (edasonbas AT yahoo.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: 14116 SUBJECT: Skynet/PROMPT observations of GRB121229a DATE: 12/12/29 06:28:57 GMT FROM: Aaron LaCluyze at U.North Carolina A. LaCluyze, N. Frank, D. Reichart, J. Haislip, K. Ivarsen, J. Moore, H. T. Cromartie, R. Egger, A. Foster, N. Frank, M. Nysewander, A. Oza, E. Speckhard, A.Trotter, and J. A. Crain report: Skynet began observing the field of GRB121229a beginning ~2 minutes after the burst using three of the PROMPT telescopes located at CTIO in Chile in B,R, and I. No optical afterglow is detected in the early observations. Calibrating to several nearby USNO B1.0 stars, and co-adding the early observations, the following 3-sigma limiting magnitudes are obtained, at a mean observing time of ~30 minutes post burst: Filt Time 3-Sig Limit B 29.7m >20.6 R 29.7m >20.7 I 33.1m >20.5 Further observations are ongoing. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14117 SUBJECT: GRB 121229A: GROND detection of the afterglow DATE: 12/12/29 06:59:20 GMT FROM: Vladimir Sudilovsky at MPE K. Varela (MPE Garching), V. Sudilovsky (MPE Garching), S. Klose (TLS Tautenburg), and J. Greiner (MPE Garching) report on behalf of the GROND team: We observed the field of GRB 121229A (Swift trigger 544347; Sonbas et al., GCN 14115) 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 at La Silla Observatory (Chile). Observations started on December 29, 2012, at 05:09 UT, 540 s after the GRB trigger. They were performed at an average seeing of 1.0" and at an average airmass of 1.8. We find a point source at the border of the XRT error circle at a position RA (J2000.0) = 12:40:24.29 DEC (J2000.0) = -50:35:39.48 with an uncertainty of 0.5" in each coordinate. Based on a total exposure time of 1500 s in g'r'i'z' and 1200 s in JHK, at a midtime of 3840s after the burst, we estimate preliminary AB magnitudes of g' = 22.2 +/- 0.2, r' = 21.5 +/- 0.1, i' = 21.3 +/- 0.1, z' = 21.1 +/- 0.1, J = 20.9 +/- 0.1, H = 20.2 +/- 0.1, and K > 19.7. This source's spectral energy distribution is best fit with a power-law of slope beta = 0.8 +/- 0.2. We suggest that this source is the afterglow of GRB 121229A. Given magnitudes are calibrated against GROND zeropoints in g'r'i'z' and 2MASS field stars in JHK, and are not corrected for the Galactic foreground extinction corresponding to a reddening of E(B-V)= 0.16 mag in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14118 SUBJECT: GRB 121229A: MAXI/GSC detection DATE: 12/12/29 10:35:00 GMT FROM: Satoshi Nakahira at JAXA/MAXI S. Nakahira (JAXA), Y. Ogawa, Y. Nishimura, T. Hanayama (Miyazaki U.), Y. Ueda, K. Hiroi, M. Shidatsu, R. Sato, T. Kawamuro (Kyoto U.), N. Kawai, M. Morii, R. Usui, K. Ishikawa (Tokyo Tech), K. Yamaoka (ISAS), S. Ueno, H. Tomida, M. Kimura, M. Ishikawa (JAXA), T. Mihara, M. Sugizaki, M. Serino, K. Morihana, T. Yamamoto, J. Sugimoto, T. Takagi, M. Matsuoka (RIKEN), A. Yoshida, T. Sakamoto, Y. Nakano (AGU), H. Tsunemi, M. Sasaki (Osaka U.), H. Negoro, M. Nakajima, M. Asada (Nihon U.), Y. Tsuboi, M. Higa (Chuo U.), M. Yamauchi, K. Yoshidome (Miyazaki U.)　 report on behalf of the MAXI team At 2012-12-29T05:01:08 UT, the MAXI/GSC detected an uncatalogued X-ray transient source. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec.) = (189.70deg, -50.84deg) = (12:38:48.98, -50:50:36.0)(J2000) with a 90% C.L. statistical error of 0.4 deg and an additional systematic uncertainty of 0.1 deg (90% containment radius). The position and time are consistent with those of GRB 121229A (Sonbas et al, GCN #14115). The transit by MAXI occurred from 2012/12/29 05:00:47 (=T0+26 s, where T0 is the Swift/BAT trigger time) to T0+70s. The averaged X-ray flux was 103 +/- 23 mCrab (2-20 keV). The spectrum is fitted by a power-law model with a photon index of 1.85 (-0.58/+0.68). There was no significant excess flux at the previous transit at 2012/12/28 18:12 UT and at the next transit at 2012/12/29 06:43 UT with an upper limit of 20 mCrab for each. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14120 SUBJECT: GRB 121229A: VLT/X-shooter redshift DATE: 12/12/29 14:38:02 GMT FROM: Valerio D'Elia at ASDC J. P. U. Fynbo (DARK/NBI), N. R. Tanvir (U. Leicester), V. D'Elia (ASDC, INAF), A. de Ugarte Postigo (IAA-CSIC and DARK/NBI), D. Malesani (DARK), O. E. Hartoog (Uva, NL), D. Xu (DARK), H. Flores (Obs. Paris), A. J. Levan (U. Warwick), B. Milvang-Jensen (DARK/NBI) We observed the field of GRB 121229A (Sonbas et al., GCN 14115; Varela et al., GCN 14117) with the ESO VLT equipped with the X-shooter spectrograph. Observations started at 07:00 UT on 2012-12-29 (2 hr after the BAT trigger), for a total exposure time of ~30 min in each of the UVB, VIS, and NIR arms, covering the wavelength range 3000-21000A. The spectrum exhibits two relatively broad troughs (centered at ~ 3800 and 4500 A) which we interpreted as Lyman-beta and -alpha features, respectively, at z=2.707. We measured the HI column density, logN(HI)~21.7, from the Lyman-alpha feature. At this redshift there are tentative indications of other metal absorption features, although they are weak and we have yet to establish their significance. The lack of strong resonance metal lines, together with the low X-ray absorption (Sonbas et al., GCN 14115), suggests a low metallicity. We also report a tentative evidence for an intervening MgII absorber at z=1.658 We acknowledge the excellent support of the ESO observing staff, in particular Maja Vu?kovi?. ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14121 SUBJECT: GRB 121229A: Enhanced Swift-XRT position DATE: 12/12/29 14:44:25 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 2407 s of XRT Photon Counting mode data and 2 UVOT images for GRB 121229A, 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 = 190.10130, -50.59414 which is equivalent to: RA (J2000): 12h 40m 24.31s Dec (J2000): -50d 35' 38.9" 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: 14122 SUBJECT: GRB 121229A: Swift/UVOT Upper Limits DATE: 12/12/29 19:01:22 GMT FROM: Samantha Oates at MSSL S. R. Oates (MSSL-UCL) and E. Sonbas (NASA/GSFC/Adiyaman Univ.) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 121229A 155 s after the BAT trigger (Sonbas et al., GCN Circ. 14115). No optical afterglow consistent with the optical position (Varela et al. GCN Circ. 14117) 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 155 305 147 >20.9 u_FC 314 563 246 >19.9 white 155 6156 363 >21.2 v 644 6466 116 >18.9 b 570 5952 216 >20.5 u 314 5747 442 >20.1 w1 3947 4136 186 >20.0 m2 670 690 19 >17.6 w2 620 6362 216 >20.1 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.16 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14123 SUBJECT: GRB 121229A, Swift-BAT refined analysis DATE: 12/12/30 02:33:05 GMT FROM: Hans Krimm at NASA-GSFC H. A. Krimm (GSFC/USRA),S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC),J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC),C. B. Markwardt (GSFC),D. M. Palmer (LANL), T. Sakamoto (AGU), E. Sonbas (NASA/GSFC/Adiyaman Univ.), 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 121229A (trigger #544347) (Sonbas, et al., GCN Circ. 14115). The BAT ground-calculated position is RA, Dec = 190.095, -50.588 deg which is RA(J2000) = 12h 40m 22.7s Dec(J2000) = -50d 35' 16.9" with an uncertainty of 2.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 39%. The mask-weighted light curve shows a broad structure beginning at least at T-60 seconds and lasting until T+60 sec. Since there is no data from before the start of the burst, T90 cannot be accurately calculated at this time. It is approximately 100 seconds. The time-averaged spectrum from T+0.00 to T+64.00 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.43 +- 0.46. The fluence in the 15-150 keV band is 4.6 +- 1.3 x 10^-7erg/cm2. The 1-sec peak photon flux measured from T+0.00 sec in the 15-150 keV band is 0.1 +- 0.0 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/544347/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14124 SUBJECT: GRB 121229A: Swift-XRT refined Analysis DATE: 12/12/30 04:13:04 GMT FROM: Phil Evans at U of Leicester G. Stratta (ASDC), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), J.A. Kennea (PSU), M.C. Stroh (PSU), D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Pagani (U. Leicester) and E. Sonbas report on behalf of the Swift-XRT team: We have analysed 13 ks of XRT data for GRB 121229A (Sonbas et al. GCN Circ. 14115), from 135 s to 68.4 ks after the BAT trigger. The data comprise 438 s in Windowed Timing (WT) mode (the first 9 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 14121). The late-time light curve (from T0+3.9 ks) can be modelled with a power-law decay with a decay index of alpha=0.23 (+0.20, -0.22). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.14 (+/-0.05). The best-fitting absorption column is 1.62 (+0.24, -0.23) x 10^22 cm^-2, at a redshift of 2.707, in addition to the Galactic value of 1.4 x 10^21 cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index of 2.14 (+0.33, -0.13) and a best-fitting absorption column consistent with the Galactic value. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.4 x 10^-11 (4.8 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Galactic foreground: 1.4 x 10^21 cm^-2 Intrinsic column: 0 (+8.4, -0) x 10^21 cm^-2 at z=2.707 Photon index: 2.14 (+0.33, -0.13) If the light curve continues to decay with a power-law decay index of 2.00, the count rate at T+24 hours will be 7.6 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.6 x 10^-13 (3.7 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/00544347. This circular is an official product of the Swift-XRT team.