//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14025 SUBJECT: GRB 121201A: a GRB with an optical counterpart DATE: 12/12/01 12:47:59 GMT FROM: David Palmer at LANL V. N. Yershov (UCL-MSSL), D. N. Burrows (PSU), N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC), S. R. Oates (UCL-MSSL), C. Pagani (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), M. H. Siegel (PSU) and T. N. Ukwatta (MSU) report on behalf of the Swift Team: At 12:25:42 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 121201A (trigger=540178). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 13.488, -42.952 which is RA(J2000) = 00h 53m 57s Dec(J2000) = -42d 57' 06" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve is incomplete at this time due to a telemetry drop out, lacking most of the time period covered by this image trigger. Activity is visible starting at T-10s, but this is coincident with a pre-planned slew. The XRT began observing the field at 12:27:37.1 UT, 115.1 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source with an enhanced position: RA, Dec 13.4676, -42.9432 which is equivalent to: RA(J2000) = 00h 53m 52.22s Dec(J2000) = -42d 56' 35.6" with an uncertainty of 2.1 arcseconds (radius, 90% containment). This location is 62 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 (1.99 x 10^20 cm^-2, Kalberla et al. 2005), with an excess column of 1.9 (+1.03/-0.96) x 10^21 cm^-2 (90% confidence). UVOT took a finding chart exposure of 150 seconds with the White filter starting 119 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 00:53:52.17 = 13.46736 DEC(J2000) = -42:56:34.4 = -42.94290 with a 90%-confidence error radius of about 0.66 arc sec. This position is 3.4 arc sec. from the center of the XRT error circle. The estimated magnitude is 19.71 with a 1-sigma error of about 0.16. No correction has been made for the expected extinction corresponding to E(B-V) of 0.01. Burst Advocate for this burst is V. N. Yershov (vny AT mssl.ucl.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: 14026 SUBJECT: GRB 121201A: BOOTES-4 optical observations DATE: 12/12/01 15:07:39 GMT FROM: Sergey Guziy at IAA CSIC S. Guziy (Mykolaiv Nat. Univ.), R. Sanchez-Ramirez (IAA-CSIC), L. Monteagudo Narvion (IAC), O. Lara, M. Jelinek (IAA-CSIC), P. Kubanek (IP AS CR), Y. Fan, X. Zhao, J. Bai, C. Wang, Y. Xin (Yunnan National Astronomical Observatory), Chenzhou Cui (Beijing National Astronomical Observatory), R. Cunniffe, A.J. Castro-Tirado, J.C. Tello and J. Gorosabel (IAA-CSIC), on behalf of a larger collaboration, report: We have observed the GRB 121201A optical afterglow (GCN 14025, Yershov et al.) with the 0.6m BOOTES-4/MET robotic telescope at the Lijiang Astronomical Observatory (China). The afterglow is clear detected in XRT and UVOT position. [GCN OPS NOTE(31dec12): As pointed out by E.Helder and confirmed by the author, the Subject-line was changed from "121123A" to "121201A".] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14027 SUBJECT: GRB 121201A: Enhanced Swift-XRT position DATE: 12/12/01 18:34:19 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 2580 s of XRT Photon Counting mode data and 5 UVOT images for GRB 121201A, 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 = 13.46759, -42.94306 which is equivalent to: RA (J2000): 00h 53m 52.22s Dec (J2000): -42d 56' 35.0" with an uncertainty of 1.6 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: 14028 SUBJECT: GRB 121201A: Swift-BAT refined analysis DATE: 12/12/01 18:45:12 GMT FROM: Scott Barthelmy at NASA/GSFC T. Sakamoto (AGU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU), V. N. Yershov (UCL-MSSL) (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 121201A (trigger #540178) (Yershov, et al., GCN Circ. 14025). The BAT ground-calculated position is RA, Dec = 13.473, -42.929 deg, which is RA(J2000) = 00h 53m 53.6s Dec(J2000) = -42d 55' 45.9" with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The mask-weighted light curve shows 3 main peaks starting at ~T-23, peaking at ~T-18, -8, & +4 sec, and ending at ~T+55 sec. T90 (15-350 keV) is 85 +- 21 sec (estimated error including systematics). The time-averaged spectrum from T-24.00 to T+71.00 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.90 +- 0.21. The fluence in the 15-150 keV band is 7.8 +- 1.0 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T-9.00 sec in the 15-150 keV band is 0.8 +- 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/540178/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14029 SUBJECT: GRB 121201A: Swift-XRT refined Analysis DATE: 12/12/02 00:48:05 GMT FROM: Phil Evans at U of Leicester 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), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. Maselli (INAF-IASFPA) and report on behalf of the Swift-XRT team: report on behalf of the Swift-XRT team: We have analysed 8.7 ks of XRT data for GRB 121201A (Yershov et al. et al. GCN Circ. 14025), from 101 s to 33.6 ks after the BAT trigger. The data comprise 24 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 Beardmore et al. (GCN. Circ 14027). The light curve can be modelled with a power-law decay with a decay index of alpha=1.24 (+0.06, -0.05). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.62 (+0.15, -0.09). The best-fitting absorption column is 2.15 (+3.39, -0.16) x 10^20 cm^-2, consistent with the Galactic value of 2.0 x 10^20 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.3 x 10^-11 (4.4 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 2.15 (+3.39, -0.16) x 10^20 cm^-2 Galactic foreground: 2.0 x 10^20 cm^-2 Excess significance: <1.6 sigma Photon index: 1.62 (+0.15, -0.09) If the light curve continues to decay with a power-law decay index of 1.24, the count rate at T+24 hours will be 1.4 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.8 x 10^-14 (6.0 x 10^-14) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00540178. This circular is an official product of the Swift-XRT team. [GCN OPS NOTE(19dec12): Per author's request, in the first sentence the Yershov/14025 reference was filled in.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14030 SUBJECT: GRB 121201A: Swift/UVOT Detection DATE: 12/12/02 00:48:41 GMT FROM: Paul Kuin at MSSL N. P. M. Kuin (MSSL-UCL) reports on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 121201A 120 s after the BAT trigger (Yershov et al., GCN Circ. 14025). A source consistent with the XRT position is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 00:53:52.16 = 13.46732 (deg.) Dec (J2000) = -42:56:34.5 = -42.94292 (deg.) with an estimated uncertainty of 0.62 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 120 270 147 20.3 +/- 0.2 white 558 578 20 19.9 +/- 0.4 white 5689 5888 200 21.3 +/- 0.4 v 608 1080 59 >19.6 b 534 1178 58 19.4 +/- 0.2 u 278 528 125 >24.8 u 6714 6914 200 20.6 +/- 0.5 w1 830 6710 432 >21.3 m2 632 6504 413 >21.1 w2 1036 6094 413 >20.8 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.01 in the direction of the burst (Schlegel et al. 1998). [GCN OPS NOTE(17feb13): The "A" was added to the GRB name in the Subject-line and in the body of the Circular.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14031 SUBJECT: GRB 121201A: GROND afterglow observations and photometric redshift DATE: 12/12/02 04:20:52 GMT FROM: Thomas Kruehler at Dark Cosmology Center T. Kruehler (DARK/NBI), S. Klose (TLS Tautenburg) and J. Greiner (MPE Garching) report on behalf of the GROND team: We observed the field of the Swift GRB 121201A (Yershov et al., GCN 14025) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m MPI/ESO telescope at La Silla Observatory (Chile). Observations started on December 02, 2012, 00:28 UT which is roughly 12.0 hr after the trigger. We clearly detect the afterglow of GRB 121201A (Yershov et al., GCN 14025) in the optical filters, but not in the NIR bands. Based on stacked images at a mid-time of 01:05 UT with an effective integration time of 25 min in g'r'i'z' and 20 min in JHKs, we estimate preliminary AB magnitudes and upper limits of: g' = 24.2 +- 0.2 r' = 23.0 +- 0.1 i' = 22.7 +- 0.1 z' = 22.5 +- 0.1 J > 21.5 H > 21.0 Ks > 19.9 These magnitudes and upper limits are calibrated against SDSS standards in the optical, and 2MASS field stars in the NIR bands. After correcting for the Galactic extinction corresponding to a reddening of E(B-V)=0.01 (Schlegel et al. 1998), a fit to this SED returns a photometric redshift of 3.6 +0.2 -0.3. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14035 SUBJECT: GRB 121201A: X-shooter redshift DATE: 12/12/02 05:43:10 GMT FROM: Antonio de Ugarte Postigo at IAA-CSIC R. Sanchez-Ramirez (IAA-CSIC), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), T. Kruehler (DARK/NBI), B. Milvang-Jensen (DARK/NBI), J.P.U. Fynbo (DARK/NBI), N. Tanvir (U. Leicester), D. Malesani (DARK/NBI), S. Schulze (PUC & MCSS), L. Kaper (U. Amsterdam), H. Flores (Obs. Paris) report on behalf of the X-shooter GTO GRB collaboration, We observed the afterglow of GRB121201A (Yeshov et al., GCN 14025, Kruehler et al. GCN 14031) using the X-shooter spectrograph on the VLT (Paranal Observatory, Chile). Observations consisted of 4x1200s exposures in the UVB and VIS arms and 8x600s exposures in the NIR, and started on 2 December 1:17 UT (12.87 hr after the burst). In a preliminary reduction we detect Ly-alpha in emission as well as several absorption features (SiIV, CIV, AlII, AlIII) at a common redshift of z=3.385, which we identify as the redshift of the GRB. We acknowledge the excellent support of the VLT staff, in particular G. Carraro.