GRB120923A

This page lists all entries on GRB120923A in GRBweb

Summary IPN Swift GCN 13796 GCN 13797 GCN 13798 GCN 13801 GCN 13802 GCN 13805 GCN 13807 GCN 13811 GCN 13812 GCN 13813 GCN 13814 GCN 13815 GCN 13817 GCN 13818 GCN 13820 GCN 13823 GCN 13825

Summary table
Variable Value Source
T0 5:16:06 UTC GCN_circulars,Swift Det
ra 303.7949° Swift
decl 6.2212° Swift
pos_error 2.46e-04° Swift
T90 27.2 s Swift
T90_start 5:16:06 UTC Swift
fluence 3.20e-07 erg/cm² Swift
redshift 7.8000 IPN
T100 27.2 s
GBM_located False
mjd 56193.219513888886 GCN_circulars,Swift Det
IPN table
GRB_name GRB120923A
ra 303.7958°
decl 6.2333°
pos_error 5.00e-02°
redshift 7.8000
Swift table
GRB_name GRB120923A
t_trigger 5:16:06 UTC
ra 303.7949°
decl 6.2212°
pos_error 2.46e-04°
T90 27.2 s
fluence 3.20e-07 erg/cm²
GCN 13796 table
GRB_name GRB120923A
GCN_number 13796
Detection_method Swift Det
t_trigger 5:16:06 UTC
ra 303.7950°
decl 6.2350°
Circular_text TITLE: GCN CIRCULAR NUMBER: 13796 SUBJECT: GRB 120923A: Swift detection of a burst DATE: 12/09/23 05:28:11 GMT FROM: Scott Barthelmy at NASA/GSFC V. N. Yershov (UCL-MSSL), S. D. Barthelmy (GSFC), H. A. Krimm (CRESST/GSFC/USRA), N. P. M. Kuin (UCL-MSSL), C. J. Mountford (U Leicester), S. R. Oates (UCL-MSSL), K. L. Page (U Leicester) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 05:16:06 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 120923A (trigger=534402). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 303.795, +6.235 which is RA(J2000) = 20h 15m 11s Dec(J2000) = +06d 14' 05" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows several overlapping peaks with a total duration of about 35 sec. The peak count rate was ~700 counts/sec (15-350 keV), at ~6 sec after the trigger. The XRT began observing the field at 05:18:26.0 UT, 139.8 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 303.79631, 6.22039 which is equivalent to: RA(J2000) = 20h 15m 11.11s Dec(J2000) = +06d 13' 13.4" with an uncertainty of 4.1 arcseconds (radius, 90% containment). This location is 52 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 9.80 x 10^20 cm^-2 (Kalberla et al. 2005). UVOT took a finding chart exposure of 150 seconds with the White filter starting 143 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 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.)
GCN 13797 table
GRB_name GRB120923A
GCN_number 13797
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 13797 SUBJECT: GRB 120923A: ROTSE-III Optical Limits DATE: 12/09/23 05:41:38 GMT FROM: Weikang Zheng at U.of Michigan W. Zheng (U Mich) and T. Guver (Sabanci U) report on behalf of the ROTSE collaboration: ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB 120923A (Swift trigger 534402; Yershov et al., GCN 13796), producing images beginning 0.7 s after the GCN notice time. An automated response took the first image at 05:17:43.7 UT, 97.4 s after the burst, under fair conditions. We took 10 5-sec, 10 20-sec and 0 60-sec exposures. These unfiltered images are calibrated relative to USNO A2.0 (R). Imaging is on going. Comparison to the DSS (second epoch) reveals no new sources within the 3-sigma Swift/BAT error circle. Individual images have limiting magnitudes ranging from 15.4-16.3; we set the following specific limits. start UT end UT t_exp(s) mlim Coadd? ------------------------------------------------------ 05:17:43 05:17:48 5 15.6 N 05:17:55 05:18:00 5 15.4 N 05:18:07 05:18:12 5 15.7 N 05:17:43 05:19:31 50 16.4 Y
GCN 13798 table
GRB_name GRB120923A
GCN_number 13798
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 13798 SUBJECT: GRB 120923A: TAROT La Silla observatory optical observations DATE: 12/09/23 06:00:56 GMT FROM: Alain Klotz at CESR-CNRS Klotz A. (IRAP-CNRS-OMP), Gendre B. (ASDC/INAF-OAR), Boer M. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report: We imaged the field of GRB 120923A detected by SWIFT (trigger 534402) with the TAROT robotic telescope (D=25cm) located at the European Southern Observatory, La Silla observatory, Chile. The observations started 104.6s after the GRB trigger (16.8s after the notice). The elevation of the field decreased from 16 degrees above horizon and weather conditions were good. The first image is trailed with a duration of 60.0s (see the description in Klotz et al., 2006, A&A 451, L39). We do not detect any OT at the XRT position (Yershov et al. GCNC 13796) with a limiting magnitude of: t0+105s to t0+165s : R > 16.0 We co-added a series of exposures: t0+178s to t0+329s : R > 17.9 Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction. Note that there is NOMAD1 0962-0583888 (R.A.=303.7958222 Decl=+06.2200278 J2000) R=17.9 very close to the XRT position. This source is detected on TAROT images but the sampling of TAROT (3.3 arcsec/pixel) does not allow to separate an OT from this star. This message may be cited.
GCN 13801 table
GRB_name GRB120923A
GCN_number 13801
Detection_method Swift-XRT Det
ra 303.7948°
decl 6.2213°
Circular_text TITLE: GCN CIRCULAR NUMBER: 13801 SUBJECT: GRB 120923A: Enhanced Swift-XRT position DATE: 12/09/23 07:49:51 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 1113 s of XRT Photon Counting mode data and 1 UVOT images for GRB 120923A, 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 = 303.79480, +6.22131 which is equivalent to: RA (J2000): 20h 15m 10.75s Dec (J2000): +06d 13' 16.7" with an uncertainty of 2.0 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.
GCN 13802 table
GRB_name GRB120923A
GCN_number 13802
Detection_method Optical
ra 303.7949°
decl 6.2212°
Circular_text TITLE: GCN CIRCULAR NUMBER: 13802 SUBJECT: GRB 120923A: Gemini afterglow detection, high-z candidate DATE: 12/09/23 10:33:17 GMT FROM: Andrew Levan at U.of Leicester A.J. Levan (U. Warwick), D.A. Perley (Caltech), N.R. Tanvir (U. Leicester) and A. Cucchiara (UCSC) report for a larger collaboration: "We observed the location of GRB 120923A (Yershov et al. GCN 13796) with Gemini-North, beginning approximately 1.4 hours after the burst. Observations were obtained in riz (with GMOS) and YJHK (with NIRI). In our optical and Y-band observations we detect no source in the refined XRT error circle (Goad et al. GCN 13801), with a preliminary z-band limit of z~24. However, in our JHK observations we clearly detect a source at a location of RA(J2000): 20:15:10.78 DEC(J2000): 06:13:16.3 (uncertainty ~0.5") Which is seen to fade in two epochs of J-band observations separated by ~3 hours, confirming it as the counterpart of GRB 120923A. The colours of this source in the IR are blue, with H-K~0.1 mag. This is strongly suggestive of a break between the Y and J-band, similar to GRB 090423, and may indicate that GRB 120923A lies at z~8. We thank Michael Hoenig for excellent support for these observations. Further observations are ongoing."
GCN 13805 table
GRB_name GRB120923A
GCN_number 13805
Detection_method Swift-UVOT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 13805 SUBJECT: GRB 120923A: Swift/UVOT Upper Limit DATE: 12/09/23 12:50:40 GMT FROM: Alice Breeveld at MSSL-UCL A. A. Breeveld (MSSL-UCL), V. N. Yershov (MSSL-UCL) and N. P. M. Kuin (MSSL-UCL) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 120923A 143 s after the BAT trigger (Yershov et al., GCN Circ. 13796). No optical afterglow consistent with the XRT or Gemini position (Goad et al., GCN Circ. 13801, Levan et al., GCN Circ. 13802) is detected in the initial UVOT exposure. A preliminary 3-sigma upper limit using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart exposure is: Filter T_start(s) T_stop(s) Exp(s) Mag white 143 293 147 >21.3 The magnitude in the table is 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).
GCN 13807 table
GRB_name GRB120923A
GCN_number 13807
Detection_method Swift-BAT Det
ra 303.7810°
decl 6.2550°
Circular_text TITLE: GCN CIRCULAR NUMBER: 13807 SUBJECT: GRB 120923A: Swift-BAT refined analysis DATE: 12/09/23 13:37:37 GMT FROM: Scott Barthelmy at NASA/GSFC C. B. Markwardt (GSFC), 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), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), 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-61 to T+242 sec from recent telemetry downlinks, we report further analysis of BAT GRB 120923A (trigger #534402) (Yershov, et al., GCN Circ. 13796). The BAT ground-calculated position is RA, Dec = 303.781, 6.255 deg, which is RA(J2000) = 20h 15m 07.3s Dec(J2000) = +06d 15' 16.8" with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 79%. The mask-weighted light curve shows the burst starting at ~T-5 sec, peaking at ~T+25 sec, and ending at ~T+30 sec. T90 (15-350 keV) is 27.2 +- 3.0 sec (estimated error including systematics). The time-averaged spectrum from T-2.93 to T+26.64 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index -0.29 +- 1.66, and Epeak of 44.4 +- 10.6 keV (chi squared 43.83 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 3.2 +- 0.8 x 10^-7 erg/cm2 and the 1-sec peak flux measured from T+24.67 sec in the 15-150 keV band is 0.6 +- 0.1 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.80 +- 0.23 (chi squared 51.10 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/534402/BA/
GCN 13811 table
GRB_name GRB120923A
GCN_number 13811
Detection_method GROND
Circular_text TITLE: GCN CIRCULAR NUMBER: 13811 SUBJECT: GRB 120923A: GROND Upper limits DATE: 12/09/24 03:01:34 GMT FROM: Sylvio Klose at TLS Tautenburg F. Knust (MPE Garching), S. Klose, A. Nicuesa Guelbenzu (both TLS Tautenburg), and J. Greiner (MPE Garching) report on behalf of the GROND team: We observed the field of GRB 120923A (Swift trigger 534402; Yershov et al., GCN 13796) 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 at 00:10 UT on Sep 24, 19 hrs after the GRB trigger, and are continuing. In a first 30 min exposure, at a mid time 00:35 UT, we do not detect any source at the position of the NIR transient reported by Levan et al. (GCN 13802) down to (AB mags, 3 sigma) g' > 23.5, r' > 23.7, i' > 23.0, z' > 23.0, J > 21.0, H > 20.4. These uper limits are derived based on calibrating the images against GROND zeropoints and 2MASS field stars and are not corrected for the Galactic foreground extinction corresponding to a reddening of E_(B-V)= 0.15 mag in the direction of the burst (Schlegel et al. 1998).
GCN 13812 table
GRB_name GRB120923A
GCN_number 13812
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 13812 SUBJECT: GRB 120923A: Swift-XRT refined Analysis DATE: 12/09/24 05:28:05 GMT FROM: Phil Evans at U of Leicester J.A. Kennea (PSU), M.C. Stroh (PSU), D.N. Burrows (PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), O.M. Littlejohns (U. Leicester), B. Sbarufatti (INAF-OAB/PSU), G. Stratta (ASDC), P. D'Avanzo (INAF-OAB) and V.N. Yershov report on behalf of the Swift-XRT team: We have analysed 9.0 ks of XRT data for GRB 120923A (Yershov et al. GCN Circ. 13796), from 151 s to 57.5 ks after the BAT trigger. The data comprise 331 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Goad et al. (GCN. Circ 13801). The light curve can be modelled with a power-law decay with a decay index of alpha=0.84 (+0.11, -0.09). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.78 (+0.47, -0.26). The best-fitting absorption column is 1.08 (+1.30, -0.10) x 10^21 cm^-2, consistent with the Galactic value of 9.8 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 4.2 x 10^-11 (5.1 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.08 (+1.30, -0.10) x 10^21 cm^-2 Galactic foreground: 9.8 x 10^20 cm^-2 Excess significance: <1.6 sigma Photon index: 1.78 (+0.47, -0.26) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00534402. This circular is an official product of the Swift-XRT team.
GCN 13813 table
GRB_name GRB120923A
GCN_number 13813
Detection_method VLA Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 13813 SUBJECT: GRB 120923A: EVLA Observations DATE: 12/09/24 16:23:18 GMT FROM: Ashley Zauderer at CfA A. Zauderer, E. Berger, and T. Laskar (Harvard) report on behalf of a larger collaboration: "We observed the position of GRB 120923A (Yershov et al; GCN 13796) beginning on 2012 Sep 24.02 UT (0.8 d after the burst) with the EVLA at a mean frequency of 5.8 GHz. We find no significant radio emission at the position of the near-IR counterpart (Levan et al; GCN 13802) or within the enhanced Swift/XRT error circle (Goad et al; GCN 13801) to a 3-sigma limit of 28 uJy."
GCN 13814 table
GRB_name GRB120923A
GCN_number 13814
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 13814 SUBJECT: GRB 120923A: CARMA Observations DATE: 12/09/24 16:24:29 GMT FROM: Ashley Zauderer at CfA A. Zauderer and E. Berger (Harvard) report on behalf of the CARMA Key Project "A Millimeter View of the Transient Universe": "We observed the position of GRB 120923A (Yershov et al; GCN 13796) with the Combined Array for Research in Millimeter Astronomy (CARMA) beginning on 2012 Sep 23.99 UT (0.77 d after the burst). Observations were obtained at a mean frequency of ~85 GHz. We find no significant millimeter emission at the position of the near-IR counterpart (Levan et al; GCN 13802) or within the enhanced Swift/XRT error circle (Goad et al; GCN 13801) to a preliminary 3-sigma limit of 0.39 mJy."
GCN 13815 table
GRB_name GRB120923A
GCN_number 13815
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 13815 SUBJECT: GRB 120923A: RAPTOR Limits During Gamma-Ray Emitting Interval DATE: 12/09/24 22:42:24 GMT FROM: James Wren at LANL J. Wren, W.T. Vestrand, P. Wozniak, and H. Davis, of Los Alamos National Laboratory report: The RAPTOR network of robotic optical telescopes made observations of Swift trigger 534402 (Yershov, et al., GCN 13796). The burst location was within the field of our wide-field monitor located in Maui, HI, which began a 10 s integration of the location at 05:16:05.26 UT, 1.0 s before the Swift trigger time and during the gamma-ray emitting interval. The next 10 s exposure began at 05:16:23.26, 17.0 s after the Swift trigger and covering the peak emission detected by the BAT (Markwardt, et al., GCN 13807). The optical counterpart (Levan, et al., GCN 13802) was not detected above our 3-sigma limiting magnitude of 10.5 based on a comparison of our unfiltered image to the Tycho-2 V-band catalog.
GCN 13817 table
GRB_name GRB120923A
GCN_number 13817
Detection_method MITSuME
Circular_text TITLE: GCN CIRCULAR NUMBER: 13817 SUBJECT: GRB 120923A: MITSuME Okayama Optical upper limits DATE: 12/09/25 05:54:47 GMT FROM: Daisuke Kuroda at OAO/NAOJ D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (OAO, NAOJ), S. Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of the MITSuME collaboration: We observed the field of GRB 120923A (Yershov et al., GCNC 13796) with the optical three color (g', Rc and Ic) CCD camera attached to the MITSuME 50cm telescope of Okayama Astrophysical Observatory. The observation started on 2012-09-23 10:00:39 UT (~4.7 h after the burst) We did not find any new point source within the enhanced XRT circle (Goad et al., GCNC 13801) in all the three bands. We also could not detect the previously reported afterglow (Levan et al., GCNC 13802). Three sigma upper limits of the OT are listed below. We used SDSS catalog for flux calibration. T0+[day] MID-UT T-EXP[sec] g' Rc Ic ------------------------------------------------------ 0.23958 11:01:05 6360.0 >20.6 >20.2 >18.9 ------------------------------------------------------ T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec]
GCN 13818 table
GRB_name GRB120923A
GCN_number 13818
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 13818 SUBJECT: GRB 120923A: RAPTOR Early Afterglow Limits DATE: 12/09/25 23:45:36 GMT FROM: James Wren at LANL J. Wren, W.T. Vestrand, P. Wozniak, and H. Davis, of Los Alamos National Laboratory report: The RAPTOR network of robotic optical telescopes made follow-up observations of Swift trigger 534402 (Yershov, et al., GCN 13796). Our narrow-field instruments in Los Alamos, NM, began imaging at 05:17:43.06 UT, 96.8 s after the Swift BAT trigger. We do not detect the optical counterpart (Levan, et al., GCN 13802) in any of our images. The following table summarizes some of our early observations. Our unfiltered images are calibrated to the USNO-B1 r-band. The start time is seconds since the BAT trigger time. The magnitude limit is the 3-sigma detection threshold. T-Start Exp-Time Mag-Limit ---------------------------------- 96.82 5.9 17.3 106.83 5.4 17.6 143.24 5.4 17.5 161.53 5.1 17.5 181.82 10.1 18.2 220.22 10.4 18.1 284.22 10.9 18.1
GCN 13820 table
GRB_name GRB120923A
GCN_number 13820
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 13820 SUBJECT: GRB 120923A: optical upper limit DATE: 12/09/26 20:24:47 GMT FROM: Alexei Pozanenko at IKI, Moscow L. Elenin (KIAM), A. Volnova (SAI MSU, IKI), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of the Swift GRB 120923A (Yershov et al., GCN 13796) with 0.45-m telescope of ISON-NM observatory starting on Sep. 23 (UT) 05:18:58, i.e 172 s after burst trigger. We took several unfiltered images of 30 s and 60 s exposures. We do not detect the optical counterpart (Levan et al., GCN 13802). A photometry of co-added frames is based on the USNO-B1.0 (R2) nearby stars is following: T0+, Exposure, OT, UL (3 sigma) mid, d (s) 0.00447 9x30 n/d 19.7 0.02839 53x30 n/d 20.5
GCN 13823 table
GRB_name GRB120923A
GCN_number 13823
Detection_method correction
Circular_text TITLE: GCN CIRCULAR NUMBER: 13823 SUBJECT: GRB 120923A: JHK Observation DATE: 12/09/28 06:48:44 GMT FROM: Myungshin Im at Seoul Nat U M. Im (CEOU/SNU), H.-I. Sung (KASI), and Y. Urata (NCU) on behalf of a larger collaboration. We observed the field of GRB 120923A (Yershov et al. GCN 13796) in JHK using KASINICS on the 1.8m telescope at the Bohyunsan observatory in Korea. The observation started at 2012-09-29 11:30:43 UT, or about 6.25 hours after the BAT alert. The stacked JHK images do not reveal a convincing detection of the afterglow reported earlier (Levan et al. GCN 13802), to the limits of ~20 AB mag in H and K (3-sigma). [GCN OPS NOTE(03oct12): See GCN Circ 13825 for a correction.]
GCN 13825 table
GRB_name GRB120923A
GCN_number 13825
Detection_method Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 13825 SUBJECT: GRB 120923A: Correction to GCN 13823 DATE: 12/09/28 07:33:43 GMT FROM: Myungshin Im at Seoul Nat U M. Im (CEOU/SNU) reports The UT date reported in GCN 13823 should be 2012-09-23, rather than 2012-09-29. We thank J. Fynbo for spotting the error.