GRB131127A

This page lists all entries on GRB131127A in GRBweb

Summary IPN Swift GCN 15516 GCN 15517 GCN 15518 GCN 15519 GCN 15520 GCN 15521 GCN 15522 GCN 15523 GCN 15525 GCN 15526 GCN 15527 GCN 15532 GCN 15548 GCN 15555 GCN 15570

Summary table
Variable Value Source
T0 10:11:35 UTC GCN_circulars,Swift Det
ra 332.7299° Swift
decl 36.6094° Swift
pos_error 1.81e-04° Swift
T90 92.1 s Swift
T90_start 10:11:35 UTC Swift
fluence 1.90e-06 erg/cm² Swift
T100 92.1 s
GBM_located False
mjd 56623.42471064815 GCN_circulars,Swift Det
IPN table
GRB_name GRB131127A
ra 332.7500°
decl 36.5833°
pos_error 5.00e-02°
Swift table
GRB_name GRB131127A
t_trigger 10:11:35 UTC
ra 332.7299°
decl 36.6094°
pos_error 1.81e-04°
T90 92.1 s
fluence 1.90e-06 erg/cm²
GCN 15516 table
GRB_name GRB131127A
GCN_number 15516
Detection_method Swift Det
t_trigger 10:11:35 UTC
ra 332.7510°
decl 36.5900°
Circular_text TITLE: GCN CIRCULAR NUMBER: 15516 SUBJECT: GRB 131127A: Swift detection of a burst DATE: 13/11/27 10:33:41 GMT FROM: Scott Barthelmy at NASA/GSFC C. B. Markwardt (NASA/GSFC), S. D. Barthelmy (GSFC), S. B. Cenko (GSFC), V. D'Elia (ASDC), D. Malesani (DARK/NBI), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL) and P. Romano (INAF-IASFPA) report on behalf of the Swift Team: At 10:11:35 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 131127A (trigger=579571). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 332.751, +36.590 which is RA(J2000) = 22h 11m 00s Dec(J2000) = +36d 35' 24" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows several overlapping peaks with a duration of about 50 sec. The peak count rate was ~1600 counts/sec (15-350 keV), at 0 sec after the trigger. The XRT began observing the field at 10:13:09.3 UT, 93.8 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source with an enhanced position: RA, Dec 332.7293, 36.6098 which is equivalent to: RA(J2000) = 22h 10m 55.03s Dec(J2000) = +36d 36' 35.2" with an uncertainty of 2.1 arcseconds (radius, 90% containment). This location is 94 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 consistent with the Galactic value of 1.15 x 10^21 cm^-2 (Kalberla et al. 2005). The initial flux in the 2.5 s image was 1.33e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 102 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. Data from the list of sources generated on-board are not available at this time. No correction has been made for the expected extinction corresponding to E(B-V) of 0.14. Burst Advocate for this burst is C. B. Markwardt (Craig.Markwardt AT nasa.gov). 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 15517 table
GRB_name GRB131127A
GCN_number 15517
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 15517 SUBJECT: GRB 131127A: MASTER-NET optical observations DATE: 13/11/27 10:38:24 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, A.Belinski, N.Tyurina, N.Shatskiy, P.Balanutsa, D.Zimnukhov, A.Kuznetsov, V.V.Chazov, D.Denisenko, A.Sankovich Sternberg Astronomical Institute, Moscow State University V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Krushinsky, I.Zalozhnih, A. Popov Ural Federal University, Yekaterinburg, Kourovka Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Tunka was pointed to the GRB131127A 503 sec after GRB time and 40 sec after notice time at 2013-11-27 10:19:58 UT in two polarizations. On our first (100s exposure) set we haven't found optical transient within SWIFT error-box (ra=22 11 00 dec=+36 35 24 r=0.050000). The 5-sigma upper limit has been about 17.5 mag The message may be cited.
GCN 15518 table
GRB_name GRB131127A
GCN_number 15518
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 15518 SUBJECT: GRB 131127A: Nanshan optical upper limit DATE: 13/11/27 12:33:21 GMT FROM: Dong Xu at DARK/NBI D. Xu (DARK/NBI), J.-Z. Liu, G.-J. Feng, H.-B. Niu, C.-H. Bai, A. Esamdin, L. Ma (XAO) report: We observed the field of GRB 131127A (Markwardt et al., GCN 15516) using 1m telescope located on Mt. Nanshan, Xinjiang, China. Observations started at 11:45:12 UT on 2013-11-27 (i.e., 1.56 hr after the BAT trigger) and a series of R-band frames were obtained. Within the SPER XRT error circle (http://www.swift.ac.uk/sper/) of this burst, no crediable optical source is detected down to a limiting magnitude of R=20.5 mag, calibrated with nearby USNO B1 field.
GCN 15519 table
GRB_name GRB131127A
GCN_number 15519
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 15519 SUBJECT: GRB 131127A: Mondy optical upper limit DATE: 13/11/27 13:18:01 GMT FROM: Alina Volnova at SAI MSU E. Klunko (ISTP), A.Volnova (IKI), M. Eselevich (ISTP), A. Pozanenko(IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of the Swift GRB 131127A (Markwardt et al., GCN 15516) with AZT-33IK telescope of Sayan observatory (Mondy) starting Nov., 27 (UT) 10:40:06. We obtained several images in R-filter with exposure of 30 and 60 seconds. Within the XRT circle (Markwardt et al., GCN 15516) we did not detect any optical object. The details of the photometry are the following: UT start, t-T0 Filter Exp. OT UL (mid, days) (s) (3 sigma) 10:40:06 0.02839 R 7*30+21*60 n/d 21.3 The photometry is based on 3 USNO-B1.0 stars: USNO-B id RA Dec R2 1265-0518495 22:11:06.80 +36:35:45.6 16.06 1265-0518432 22:10:59.37 +36:35:56.7 16.45 1266-0522367 22:10:48.55 +36:36:43.7 15.45
GCN 15520 table
GRB_name GRB131127A
GCN_number 15520
Detection_method Swift-XRT Det
ra 332.7301°
decl 36.6093°
Circular_text TITLE: GCN CIRCULAR NUMBER: 15520 SUBJECT: GRB 131127A: Enhanced Swift-XRT position DATE: 13/11/27 20:23:42 GMT FROM: Phil Evans at U of Leicester P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team. Using 3638 s of XRT Photon Counting mode data and 7 UVOT images for GRB 131127A, 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 = 332.73008, +36.60929 which is equivalent to: RA (J2000): 22h 10m 55.22s Dec (J2000): +36d 36' 33.5" with an uncertainty of 1.7 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 15521 table
GRB_name GRB131127A
GCN_number 15521
Detection_method Swift-BAT Det
ra 332.7140°
decl 36.5960°
Circular_text TITLE: GCN CIRCULAR NUMBER: 15521 SUBJECT: GRB 131127A, Swift-BAT refined analysis DATE: 13/11/27 20:49:44 GMT FROM: Craig Markwardt at NASA/GSFC C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/UMBC), D. M. Palmer (LANL), T. Sakamoto (AGU), 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+960 sec from the recent telemetry downlink, we report further analysis of BAT GRB 131127A (trigger #579571) (Markwardt, et al., GCN Circ. 15516). The BAT ground-calculated position is RA, Dec = 332.714, 36.596 deg which is RA(J2000) = 22h 10m 51.3s Dec(J2000) = +36d 35' 46.9" with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 39%. The mask-weighted light curve has multiple peaks. The first set of about 3 peaks occurs before the initial trigger between T-60 and T-38 sec. The main set of about 7-8 peaks occurs between T-5 and T+40 sec. The peak emission occurs at about T+0 sec. T90 (15-350 keV) is 92.1 +- 10.2 sec (estimated error including systematics). The time-averaged spectrum from T-59.4 to T+37.5 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.34 +- 0.16. The fluence in the 15-150 keV band is 1.9 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T-0.54 sec in the 15-150 keV band is 1.3 +- 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/579571/BA/
GCN 15522 table
GRB_name GRB131127A
GCN_number 15522
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 15522 SUBJECT: GRB 131127A. 1.5m OSN optical limit DATE: 13/11/27 22:24:50 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia A. Sota, J. Gorosabel and A. J. Castro-Tirado (IAA-CSIC Granada) on behalf of a larger collaboration, report: "Following the detection of GRB 131127A by Swift (Markwardt et al. GCNC 15516), we have conducted I-band observations with the 1.5m OSN telescope at Observatorio de Sierra Nevada (Granada, Spain), starting on 27 Nov 18:26 UT,(i.e. 8.2-hr post burst). A stack of 17 x 300s images shows nothing at the enhanced Swift/XRT position (Evans et al. GCNC 15520) down to I = 21".
GCN 15523 table
GRB_name GRB131127A
GCN_number 15523
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 15523 SUBJECT: GRB 131127A: Swift-XRT refined Analysis DATE: 13/11/27 22:33:03 GMT FROM: Phil Evans at U of Leicester A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), B.P. Gompertz (U. Leicester), A. Maselli (INAF-IASFPA), A. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), M.C. Stroh (PSU), D.N. Burrows (PSU), J.A. Kennea (PSU) and C.B. Markwardt report on behalf of the Swift-XRT team: We have analysed 6.5 ks of XRT data for GRB 131127A (Markwardt et al. GCN Circ. 15516), from 84 s to 24.3 ks after the BAT trigger. The data comprise 62 s in Windowed Timing (WT) mode (the first 8 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 Evans et al. (GCN. Circ 15520). The late-time light curve (from T0+4.5 ks) can be modelled with a power-law decay with a decay index of alpha=1.55 (+0.26, -0.22). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 3.8 (+0.4, -0.3). The best-fitting absorption column is 3.9 (+0.7, -0.6) x 10^21 cm^-2, in excess of the Galactic value of 1.2 x 10^21 cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index of 2.22 (+/-0.15) and a best-fitting absorption column of 2.5 (+0.5, -0.4) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.6 x 10^-11 (6.1 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 2.5 (+0.5, -0.4) x 10^21 cm^-2 Galactic foreground: 1.2 x 10^21 cm^-2 Excess significance: 5.1 sigma Photon index: 2.22 (+/-0.15) If the light curve continues to decay with a power-law decay index of 1.55, the count rate at T+24 hours will be 2.3 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.0 x 10^-14 (1.4 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/00579571. This circular is an official product of the Swift-XRT team.
GCN 15525 table
GRB_name GRB131127A
GCN_number 15525
Detection_method Swift-XRT Other
ra 332.7312°
decl 36.6092°
Circular_text TITLE: GCN CIRCULAR NUMBER: 15525 SUBJECT: GRB 131127A: RATIR Optical and NIR Observations, High-z Candidate DATE: 13/11/28 08:41:53 GMT FROM: Nat Butler at Az State U Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (ORAU/GSFC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jos A. de Diego (UNAM), Leonid Georgiev (UNAM), Jess Gonzlez (UNAM), Carlos Romn-Ziga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report: We observed the field of GRB 131127A (Markwardt, et al., GCN 15516) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronmico Nacional on Sierra San Pedro Mrtir from 2013/11 28.11 to 2013/11 28.26 UTC (16.42 to 19.94 hours after the BAT trigger), obtaining a total of 2.49 hours exposure in the r and i bands and 1.04 hours exposure in the Z, Y, J, and H bands. We do not detect any sources within the Enhanced Swift-XRT error circle (Evans et al., GCN 15520), in comparison with 2MASS, we obtain the following upper limits (3-sigma): r > 24.19 i > 23.53 Z > 22.78 Y > 22.16 J > 22.04 H > 21.48 However, we do detect a red source just outside (3.3" away from the center) of the XRT position, at a position RA, DEC = 332.731227 , 36.609171 (J2000, +/- 0.5"). We measure: r = 24.21 +/- 0.35 i = 22.48 +/- 0.11 Z = 21.85 +/- 0.16 Y = 21.22 +/- 0.15 J = 21.03 +/- 0.14 H = 20.88 +/- 0.20 The faint flux in r band relative to the redder bands could be due to IGM attenuation at high redshift, z ~ 5. We cannot confirm fading of this source. Further observations of this source are encouraged. The magnitudes above are in the AB system and are not corrected for Galactic extinction, E[B-V]~0.1, in the direction of the GRB. We thank the staff of the Observatorio Astronmico Nacional in San Pedro Mrtir.
GCN 15526 table
GRB_name GRB131127A
GCN_number 15526
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 15526 SUBJECT: GRB 131127A: AROMA-N Optical Observation DATE: 13/11/28 11:36:56 GMT FROM: Takanori Sakamoto at AGU D. Kawamura, T. Sakamoto, I. Takahashi, S. Sugai, A. Yoshida (AGU) We observed the field of GRB 131127A detected by Swift (trigger #579571; Markwardt et al., GCN Circ. 15516) with the 12-inch AGU Robotic Optical Monitor for Astrophysical object - Narrow (AROMA-N) located at the Sagamihara campus of Aoyama Gakuin University. 60 images of 60 sec exposures were taken in the R filter starting from November 27 10:42:18 (UT) about 30 minutes after the trigger and stopped on November 27 11:48:15 (UT). We do not detect the optical afterglow both in the individual images and the stacked image, which combined 57 good quality images, inside the enhanced XRT position (Evans, et al., GCN #15520). The estimated five sigma upper limit of the combined image (total exposure of 3420 sec) is ~16.6 mag using the USNO-B1 catalog. [GCN OPS NOTE(29nov13): Per author's request, the "November 11" date was changed to "November 27" in two places.]
GCN 15527 table
GRB_name GRB131127A
GCN_number 15527
Detection_method Swift-UVOT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 15527 SUBJECT: GRB 131127A: Swift/UVOT Upper Limits DATE: 13/11/28 11:56:24 GMT FROM: Alice Breeveld at MSSL-UCL A. A. Breeveld (UCL-MSSL) and C. B. Markwardt (NASA/GSFC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 131127A 102 s after the BAT trigger (Markwardt et al., GCN Circ. 15516). No optical afterglow consistent with the XRT position (Evans et al. GCN Circ. 15520) nor the RATIR position (Butler et al. GCN Circ. 15525) 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 102 252 147 >21.4 u_FC 315 565 246 >20.6 white 102 6711 746 >22.3 v 645 7024 373 >20.3 b 571 6506 452 >21.2 u 315 6300 678 >21.1 w1 694 6095 432 >20.6 m2 669 5890 269 >20.1 w2 621 6916 471 >20.9 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.14 in the direction of the burst (Schlegel et al. 1998).
GCN 15532 table
GRB_name GRB131127A
GCN_number 15532
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 15532 SUBJECT: GRB 131127A: Bassano Bresciano Observatory optical upper limit DATE: 13/11/28 15:00:35 GMT FROM: Ulisse Quadri at Bassano Bresciano Obs U.Quadri, L.Strabla and R.Girelli report: We imaged the field of GRB 131127A detected by SWIFT(trigger 00579571) with the robotic telescope of (IAU station 565) Bassano Bresciano Observatory, Italy (www.osservatoriobassano.org). The observations started 9h 2m. after the GRB trigger,with our schmidt telescope D=320/400 mm F/D=3.1. Weather conditions were good. We co-added a series of 5 exposures of 120 sec each. We did not found any optical counterpart in the error box of the XRTcandidate (Markwardt et al., GCN 15516). Start End R.lim 542min 554min 18.5 Magnitudes were estimated with the USNO-B1 cat. and are not corrected for galactic dust extinction. The message may be cited.
GCN 15548 table
GRB_name GRB131127A
GCN_number 15548
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 15548 SUBJECT: GRB 131127A: CQUEAN riz Observation DATE: 13/11/29 14:43:29 GMT FROM: Myungshin Im at Seoul Nat U Myungshin Im, Changsu Choi (CEOU/SNU), Hyein Lee, Huynh Ahn N. Le, and Soojong Pak (Kyunghee Univ.) We observed the field of GRB 131127A (Markwardt et al. GCN 15516), using CQEUAN (Park et al. 2012) on the 2.1-m Otto-Struve telescope at the McDonald Observatory in Texas, US. The observation started at 2013-11-29 01:31:43 UT, or about 1.63 days after the BAT alert. A series of images were taken in r, i, and z-band for about 45 min. We identify the red source reported in Butler et al. (GCN 15525), but no significant fading of the source was found with z = 21.90 +- 0.15 AB mag, consistent with Z = 21.85 +- 0.16 mag from Butler et al. (GCN 15525). This suggests that the red source may not be the GRB afterglow, or the light curve is changing very slowly.
GCN 15555 table
GRB_name GRB131127A
GCN_number 15555
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 15555 SUBJECT: GRB 131127A: RATIR Rejection of High-z Candidate DATE: 13/11/29 20:57:31 GMT FROM: Nat Butler at UC berkeley Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (ORAU/GSFC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jos A. de Diego (UNAM), Leonid Georgiev (UNAM), Jess Gonzlez (UNAM), Carlos Romn-Ziga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report: We again observed the field of GRB 131127A (Markwardt, et al., GCN 15516) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronmico Nacional on Sierra San Pedro Mrtir from 2013/11 29.09 to 2013/11 29.17 UTC (40.06 to 41.98 hours after the BAT trigger), obtaining a total of 1.42 hours exposure in the r and i bands and 0.60 hours exposure in the Z, Y, J, and H bands. For the red source 3.3" away from the center of the XRT positions (Butler et al., GCN 15525), in comparison with 2MASS, we obtain: r > 23.78 i = 22.68 +/- 0.16 (0.20 +/- 0.19) Z = 22.02 +/- 0.26 (0.17 +/- 0.31) Y = 21.31 +/- 0.24 (0.09 +/- 0.28) J = 21.26 +/- 0.29 (0.23 +/- 0.32) H = 20.55 +/- 0.24 (-0.33 +/- 0.31) The change in magnitude relative to the observations on the previous night are given in the parentheses. There is slight (~<1-sigma) evidence for a fade in most bands, but the shallowness ~t^(-0.2) of the fade is not expected for a GRB afterglow. We conclude, as did Im et al. (GCN 15548), that this source is not the afterglow of GRB 131127A. We thank the staff of the Observatorio Astronmico Nacional in San Pedro Mrtir.
GCN 15570 table
GRB_name GRB131127A
GCN_number 15570
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 15570 SUBJECT: GRB 131127A: optically dark burst DATE: 13/12/03 16:26:09 GMT FROM: Alina Volnova at SAI MSU A.Volnova (IKI), E. Klunko (ISTP), M. Eselevich (ISTP), A. Pozanenko(IKI) report on behalf of larger GRB follow-up collaboration: We report about revised photometry of the GRB 131127A (Markwardt et al., GCN 15516) published earlier (Klunko et al., GCN 15519). Using combined image of full data set of the observations on Nov. 27 we do not detect any optical counterpart in the enhanced XRT error circle (Evans et al., GCN 15520). The details of the photometry are the following: UT start t-T0 Filter Exp. OT UL (mid, days) (s) (3 sigma) 10:40:06 0.04680 R 4650 n/d 22.5 The photometry is based on the same 3 USNO-B1.0 stars listed in the GCN 15519. The deep upper limit obtained at ~67 min (mid time) after burst trigger together with Swift/XRT observations (www.swift.ac.uk/xrt_curves/00579571/flux.qdp) suggests the upper limit of optical-to-X-ray spectral slope beta_OX = -0.02 and classify the GRB 131127A as a dark burst according to Jakobsson (Jakobsson et al., 2004, ApJ, 614, L21).