GRB120811C

This page lists all entries on GRB120811C in GRBweb

Summary Fermi GBM IPN Swift GCN 13622 GCN 13623 GCN 13624 GCN 13625 GCN 13626 GCN 13628 GCN 13629 GCN 13630 GCN 13631 GCN 13632 GCN 13634 GCN 13635 GCN 13636 GCN 13637 GCN 13642 GCN 13679 GCN 13693

Summary table
Variable Value Source
GRB_name_Fermi GRB120811649
T0 15:34:47.924 UTC Fermi_GBM
ra 199.6826° Swift
decl 62.3008° Swift
pos_error 6.73e-05° Swift
T90 14.336 s Fermi_GBM
T90_error 6.557 s Fermi_GBM
T90_start 15:34:47.924 UTC Fermi_GBM
fluence 3.45e-06 erg/cm² Fermi_GBM
fluence_error 2.11e-07 erg/cm² Fermi_GBM
redshift 2.6710
T100 30.876 s
GBM_located False
mjd 56150.649165787036 Fermi_GBM
Fermi GBM table
GRB_name_Fermi GRB120811649
trigger_name bn120811649
ra 199.7092°
decl 62.2911°
pos_error 5.33e+00°
datum 2012-08-11
t_trigger 15:34:55.092 UTC
T90 14.336 s
T90_error 6.557 s
T90_start 15:34:47.924 UTC
fluence 3.45e-06 erg/cm²
fluence_error 2.11e-07 erg/cm²
flux_1024 7.70e+00 erg/cm²/s
flux_1024_error 4.52e-01 erg/cm²/s
flux_1024_time 3.01e+00 erg/cm²/s
flux_64 1.37e+01 erg/cm²/s
flux_64_error 2.82e+00 erg/cm²/s
IPN table
GRB_name GRB120811C
ra 199.7083°
decl 62.2833°
pos_error 5.00e-02°
redshift 2.6710
Swift table
GRB_name GRB120811C
t_trigger 15:34:52 UTC
ra 199.6826°
decl 62.3008°
pos_error 6.73e-05°
T90 26.8 s
fluence 3.00e-06 erg/cm²
redshift 2.6710
GCN 13622 table
GRB_name GRB120811C
GCN_number 13622
Detection_method Swift Det
t_trigger 15:34:52 UTC
ra 199.7090°
decl 62.2910°
Circular_text TITLE: GCN CIRCULAR NUMBER: 13622 SUBJECT: GRB 120811C: Swift detection of a burst with an optical counterpart DATE: 12/08/11 15:52:41 GMT FROM: Scott Barthelmy at NASA/GSFC B. N. Barlow (PSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), D. Grupe (PSU), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL) and B.-B. Zhang (PSU) report on behalf of the Swift Team: At 15:34:52 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 120811C (trigger=530689). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 199.709, +62.291 which is RA(J2000) = 13h 18m 50s Dec(J2000) = +62d 17' 29" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single bright peak with a duration of about 35 sec. The peak count rate was ~7000 counts/sec (15-350 keV), at ~6 sec after the trigger. The XRT began observing the field at 15:36:00.8 UT, 68.7 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 199.6833, 62.3027 which is equivalent to: RA(J2000) = +13h 18m 43.99s Dec(J2000) = +62d 18' 09.7" with an uncertainty of 5.0 arcseconds (radius, 90% containment). This location is 60 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 2.97e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 75 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 13:18:43.81 = 199.68253 DEC(J2000) = +62:18:02.7 = 62.30076 with a 90%-confidence error radius of about 0.75 arc sec. This position is 7.1 arc sec. from the center of the XRT error circle. The estimated magnitude is 18.40 with a 1-sigma error of about 0.15. No correction has been made for the expected extinction corresponding to E(B-V) of 0.03. Burst Advocate for this burst is B. N. Barlow (bnb2 AT psu.edu). 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 13623 table
GRB_name GRB120811C
GCN_number 13623
Detection_method Optical
ra 13.0000°
decl 62.0000°
Circular_text TITLE: GCN CIRCULAR NUMBER: 13623 SUBJECT: GRB 120811C: MASTER-Amur observations of fading OT DATE: 12/08/11 20:32:22 GMT FROM: Denis Denisenko at SAI MSU D. Denisenko, E. Gorbovskoy, V. Lipunov, V. Kornilov, D. Kuvshinov, A. Belinski, N. Tyurina, N. Shatskiy, P. Balanutsa, D. Zimnukhov, A. Kuznetsov, V.V. Chazov, A. Sankovich Lomonosov Moscow State University, Sternberg Astronomical Institute 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. Krushinski, I. Zalozhnich, A. Popov, A. Bourdanov, A. Punanova Ural Federal University H. Levato, C. Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) C. Mallamaci, C. Lopez, F. Podest Observatorio Astronomico Felix Aguilar (OAFA) report: MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Blagoveschensk was pointed to GRB 120811C (Barlow et al., GCN 13622) 665 sec after GRB time, at 2012-08-11 15:45:57 UT. Observations were performed simultaneously in two tubes with mutually perpendicular polarizations. First two pairs of images were obtained with 130 and 160 sec exposures, followed by the set of 180-sec exposures. On our images we find the fading optical transient at the coordinates: R.A. (J2000) = 13 18 44.01 Dec. (J2000) = +62 18 02.7 which are consistent with the position of UVOT candidate afterglow reported in GCN 13622. Photometry of GRB 120811C afterglow was performed using SDSS J131828.08+621651.3 (r=14.74) as the reference star. To improve the signal-to-noise ratio, images were combined by four. The resulting magnitudes of the afterglow in the Western tube with a better image quality (FWHM=2.6-3.2") are listed in the Table below. ---------------------------------------------- T_mid UT | T-T0, s | Exptime | Mag. | Mag.err ---------+---------+---------+-------+-------- 15:51:48 | 1016 | 650 | 18.4 | 0.10 16:04:46 | 1794 | 720 | 18.9 | 0.17 16:18:37 | 2625 | 720 | 19.3 | 0.27 16:32:27 | 3455 | 720 | 19.0 | 0.24 16:46:16 | 4284 | 720 | <19.5 | N/A 17:00:04 | 5112 | 720 | <19.5 | N/A ---------------------------------------------- The detailed analysis of the complete data set is continuing. This message can be cited.
GCN 13624 table
GRB_name GRB120811C
GCN_number 13624
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 13624 SUBJECT: GRB 120811C: TAROT Calern observatory optical observations DATE: 12/08/11 21:03:08 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 120811C detected by SWIFT (trigger 530689) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France. The observations started 3.98h after the GRB trigger. The elevation of the field decreased from 50 degrees above horizon and weather conditions were good. We co-added a series of exposures but we do not find any optical transcient at the afterglow position (Barlow et al. GCNC 13622, Denisenko et al. GCNC 13623): ------------------------------- T-T0 start | T-T0 End | Mag. | -----------+----------+-------+ 246 min | 313 min | >19.5 | ------------------------------- Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction. This message may be cited.
GCN 13625 table
GRB_name GRB120811C
GCN_number 13625
Detection_method Swift-XRT Det
ra 199.6829°
decl 62.3007°
Circular_text TITLE: GCN CIRCULAR NUMBER: 13625 SUBJECT: GRB 120811C: Enhanced Swift-XRT position DATE: 12/08/11 21:13:09 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 1291 s of XRT Photon Counting mode data and 2 UVOT images for GRB 120811C, 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 = 199.68285, +62.30068 which is equivalent to: RA (J2000): 13h 18m 43.88s Dec (J2000): +62d 18' 02.4" 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 13626 table
GRB_name GRB120811C
GCN_number 13626
Detection_method Optical
ra 199.6826°
decl 62.3007°
Circular_text TITLE: GCN CIRCULAR NUMBER: 13626 SUBJECT: GRB 120811C: RTT150 optical observations DATE: 12/08/11 21:53:06 GMT FROM: Rodion Burenin at IKI, Moscow A. Galeev (Kazan Federal University), I. Khamitov (TUG), I. Bikmaev, N. Sakhibullin (Kazan Federal University), R. Burenin, M. Pavlinsky, R. Sunyaev (IKI), Z. Eker (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.) report: We observed the field of the Swift-BAT GRB 120811C (Barlow et al. GCN 13622) with Russian-Turkish 1.5-m telescope (RTT150, Bakirlitepe, TUBITAK National Observatory, Turkey), starting at 11 Aug, 18:52 UT, i.e. approximately 3.3 hours after the burst, using TFOSC instrument. We made a serie of 300-600s images in R and V. The afterglow is detected at the position: RA=13:18:43.83, DEC=62:18:02.6 (J2000) with positional error about 0.1 arcsec, which is consistent with that measured by UVOT and MASTER (Denisenko et al., GCN 13623). We measured the afterglow magnitude as m_R=20.00+-0.05 (calibrated relative to USNO-B1 stars). Observations are continuing.
GCN 13628 table
GRB_name GRB120811C
GCN_number 13628
Detection_method Other
redshift 2.6710
Circular_text TITLE: GCN CIRCULAR NUMBER: 13628 SUBJECT: GRB 120811C: Redshift from OSIRIS/GTC DATE: 12/08/11 23:14:09 GMT FROM: Antonio de Ugarte Postigo at IAA-CSIC C. C. Thoene (IAA-CSIC), A. de Ugarte Postigo (IAA-CSIC, DARK), J. Gorosabel, R. Sanchez-Ramirez (IAA-CSIC) and J. P. U. Fynbo (DARK) G. Gomez Velarde (GTC) report on behalf of a larger collaboration: We observed the afterglow of GRB 120811C (Barlow et al., GCN 13622) with OSIRIS at the 10.4m GTC telescope starting at UT 22:07 (6.5 hr after the burst) for a total exposure time of 2400s. We used grism 1000B covering the wavelength range between 3700 and 7800 Angstrom. Despite Calima, the continuum is clearly detected and the spectrum shows strong Ly alpha and Ly beta absorption as well as a number of absorption lines (SII, SiII, OI, CII, CIV, SiIV, AlII, AlIII, NiII, ZnII and SiII*) at a common redshift of z=2.671.
GCN 13629 table
GRB_name GRB120811C
GCN_number 13629
Detection_method Swift-UVOT Det
ra 199.6826°
decl 62.3008°
Circular_text TITLE: GCN CIRCULAR NUMBER: 13629 SUBJECT: GRB 120811C: Swift/UVOT Detection DATE: 12/08/12 01:58:39 GMT FROM: Paul Kuin at MSSL P. Kuin, S. R. Oates (MSSL-UCL) and B.N. Barlow (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 120811C 76 s after the BAT trigger (Barlow et al., GCN Circ. 13622). A source consistent with the XRT position Evans et al., GCN Circ. 13625 is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 13:18:43.82 = 199.68258 (deg.) Dec (J2000) = +62:18:02.8 = 62.30077 (deg.) with an estimated uncertainty of 0.52 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 76 226 147 18.59 +/- 0.05 v 620 1243 78 18.49 +/- 0.19 b 544 739 39 18.95 +/- 0.19 u 288 538 246 18.61 +/- 0.09 w1 670 1464 97 >20.0 m2 819 1439 78 >20.5 w2 595 1219 78 >19.7 The absence of a detection in the uv bands is consistent with the reported redshift from Thoene et al., GCN Circ. 13628. The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.03 in the direction of the burst (Schlegel et al. 1998).
GCN 13630 table
GRB_name GRB120811C
GCN_number 13630
Detection_method Swift-XRT Other
Circular_text TITLE: GCN CIRCULAR NUMBER: 13630 SUBJECT: GRB 120811C: Swift-XRT refined Analysis DATE: 12/08/12 06:52:03 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester), O.M. Littlejohns (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. Maselli (INAF-IASFPA), M.C. Stroh (PSU), D.N. Burrows (PSU), J.A. Kennea (PSU), J.P. Osborne (U. Leicester) and B.N. Barlow report on behalf of the Swift-XRT team: We have analysed 6.5 ks of XRT data for GRB 120811C (Barlow et al. GCN Circ. 13622), from 56 s to 40.2 ks after the BAT trigger. The data comprise 137 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 13625). The light curve can be modelled with a series of power-law decays. The initial decay index is alpha=3.12 (+0.13, -0.14). At T+224 s the decay flattens to an alpha of 0.44 (+0.12, -0.27) before breaking again at T+1468 s to a final decay with index alpha=1.06 (+0.19, -0.09). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.74 (+0.14, -0.13). The best-fitting absorption column is 1.08 (+0.22, -0.20) x 10^21 cm^-2, in excess of the Galactic value of 2.1 x 10^20 cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index of 2.00 (+/-0.15) and a best-fitting absorption column of 8.8 (+3.4, -3.1) x 10^20 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.6 x 10^-11 (4.5 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 8.8 (+3.4, -3.1) x 10^20 cm^-2 Galactic foreground: 2.1 x 10^20 cm^-2 Excess significance: 3.6 sigma Photon index: 2.00 (+/-0.15) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00530689. This circular is an official product of the Swift-XRT team.
GCN 13631 table
GRB_name GRB120811C
GCN_number 13631
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 13631 SUBJECT: GRB 120811C: Bassano Bresciano Observatory optical observations DATE: 12/08/12 07:26:59 GMT FROM: Ulisse Quadri at Bassano Bresciano Obs U.Quadri, L.Strabla and R.Girelli, A.Quadri report: We imaged the field of GRB 120811C detected by SWIFT(trigger 530689) with the robotic telescope of (IAU station 565) Bassano Bresciano Observatory, Italy. The observations started 266min. after the GRB trigger,with our schmidt telescope D=320 mm F/D=3.1. Weather conditions were good. We co-added a series of 30 exposures. We did not found any optical counterpart in the error box of the XRTcandidate (Barlow et al. GCNC 13622). Start End Vlim 266min 326min 19.2 Magnitudes were estimated with the UCAC-3 The message may be cited.
GCN 13632 table
GRB_name GRB120811C
GCN_number 13632
Detection_method Swift-BAT Det
redshift 2.6700
Circular_text TITLE: GCN CIRCULAR NUMBER: 13632 SUBJECT: GRB 120811C: NOT redshift DATE: 12/08/12 11:54:19 GMT FROM: Dong Xu at Weizmann Inst J. P. U. Fynbo (DARK/NBI), D. Xu (WIS), P. Jakobsson (U. Iceland), D. Armstrong (U. Warwick), R. Cardenes (NOT) report on behalf of a larger collaboration: We observed the optical afterglow of GRB 120811C (Barlow et al., GCN 13622) using the 2.5m Nordic Optical Telescope (NOT) equipped with ALFOSC. Spectroscopic observations started at 21:58 UT on 2012-08-11 (i.e., 6.4 hr after the BAT trigger) with exposure time of 3x1800s, covering the wavelength range of ~3800A to ~8000A. The afterglow was detected in each of the 1800s frames though the weather was dusty to a certain degree. The spectrum exhibits a clear Damped Lyman Alpha (DLA) absorption feature at about 4460A. Redward of Lyman alpha the spectrum shows quite a few significant absorption lines, including Si II, O I, C II, C IV, Si IV, all at a common redshift of z=2.67, in good agreement with the measurement in Thoene at al. (GCN 13628).
GCN 13634 table
GRB_name GRB120811C
GCN_number 13634
Detection_method Swift-BAT Det
ra 199.6900°
decl 62.2970°
Circular_text TITLE: GCN CIRCULAR NUMBER: 13634 SUBJECT: GRB 120811C: Swift-BAT refined analysis DATE: 12/08/12 13:43:42 GMT FROM: Scott Barthelmy at NASA/GSFC H. A. Krimm (GSFC/USRA), B. N. Barlow (PSU), S. D. Barthelmy (GSFC), T. Sakamoto (GSFC/UMBC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (GWU) (i.e. the Swift-BAT team): Using the data set from T-240 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 120811C (trigger #530689) (Barlow, et al., GCN Circ. 13622). The BAT ground-calculated position is RA, Dec = 199.690, 62.297 deg, which is RA(J2000) = 13h 18m 45.5s Dec(J2000) = +62d 17' 50.3" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 89%. The mask-weighted light curve shows a nearly symmetric peak starting at ~T-10 sec, peaking at ~T+6 sec, and ending at ~T+40 sec. T90 (15-350 keV) is 26.8 +- 3.7 sec (estimated error including systematics). The time-averaged spectrum from T-9.7 to T+42.9 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.40 +- 0.30, and Epeak of 42.9 +- 5.7 keV (chi squared 59.5 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 3.0 +- 0.3 x 10^-6 erg/cm2 and the 1-sec peak flux measured from T+5.27 sec in the 15-150 keV band is 4.1 +- 0.2 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.04 +- 0.06 (chi squared 74.5 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/530689/BA/
GCN 13635 table
GRB_name GRB120811C
GCN_number 13635
Detection_method Swift-BAT Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 13635 SUBJECT: GRB 120811C: MASTER-Tunka OT observations DATE: 12/08/13 07:05:34 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, A.Kuznetsov, 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.Krushinski, I.Zalozhnih, A. Popov Ural Federal University, 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 GRB120811C (Barlow et al., GCN 13622) 40 sec s after notice time and 676 sec after GRB time at 2012-08-11 15:46:08.449 UT. On our first (130s exposure) set we have found OT within SWIFT-BAT error-box in two polarizations. The preliminary robotic photometry (m=0.2B + 0.8R, Usno B magnitudes) is: datetime coord2000 Band mag error 2012-08-11 15:46:08.449 13h 18m 43.90s , +62d 18m 02s.1 P| 17.3 0.2 2012-08-11 15:46:09.684 13h 18m 43.86s , +62d 18m 02s.3 P- 17.2 0.1 2012-08-11 15:49:12.268 13h 18m 43.76s , +62d 18m 02s.3 P| 17.6 0.2 2012-08-11 15:49:12.282 13h 18m 43.93s , +62d 18m 02s.6 P- 17.6 0.2 2012-08-11 15:52:52.452 13h 18m 43.75s , +62d 18m 01s.8 P| 17.8 0.2 So, MASTER-Net have simultaneous optical observations in four polarizations (see Denisenko et al., GCN 13623) of GRB120811C. The message may be cited.
GCN 13636 table
GRB_name GRB120811C
GCN_number 13636
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 13636 SUBJECT: GRB 120811C: RTT150 optical observations DATE: 12/08/13 17:29:30 GMT FROM: Rodion Burenin at IKI, Moscow A. Galeev (Kazan Federal University), I. Khamitov (TUG), I. Bikmaev, N. Sakhibullin (Kazan Federal University), R. Burenin, M. Pavlinsky, R. Sunyaev (IKI), Z. Eker (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.) report: We continued the observations of the field of the Swift-BAT GRB 120811C (Barlow et al. GCN 13622, Galeev et al., GCN 13626) with Russian-Turkish 1.5-m telescope (RTT150, Bakirlitepe, TUBITAK National Observatory, Turkey). The second epoch observations were started at 12 Aug, 18:38 UT, i.e. approximately 27.05 hours after the burst. We made a serie of 300s images in R using TFOSC instrument. The afterglow was clearly detected in the combined image. Using USNO-B1 stars as reference, we estimated the afterglow magnitude as m_R=22.3+-0.2. Fitting this point together with the data from RTT150 first epoch observations (Galeev et al., GCN 13626), gives the power law decay with index alpha = 1.04 +- 0.05, consistent with late time decay in X-rays, as it was observed with XRT (Evans et al., GCN 13630). When all RTT150 data are compared with the data of MASTER telescopes (Denisenko et al., GCN 13623, Ivanov et al., 13635), the power law break at few hours time scale is found, approximately consistent with the position of second break observed in X-rays with XRT (Evans et al., GCN 13630). However, better cross-calibration between RTT and MASTER photometry should be done for more reliable light curve modelling. The light curve and direct images of the field can be found at: http://hea.iki.rssi.ru/grb/120811c/indexeng.html
GCN 13637 table
GRB_name GRB120811C
GCN_number 13637
Detection_method VLA Det
Circular_text TITLE: GCN CIRCULAR NUMBER: 13637 SUBJECT: GRB 120811C: EVLA Observations DATE: 12/08/13 20:49:36 GMT FROM: Tanmoy Laskar at Harvard U T. Laskar, A. Zauderer and E. Berger (Harvard) report: "We observed the position of GRB 120811C (Barlow et al. GCN 13622) with the EVLA at 2012 Aug 11.79 UT (1.14 days after the burst). No significant radio emission is detected at the enhanced Swift-XRT position (Evans et al. GCN 13625), the UVOT position (Kuin et al. GCN 13629) or optical position (Denisenko et al. GCN 13623; Galeev et al. GCN 13626; Ivanov et al. GCN 13635), to a three-sigma upper limit of 76 uJy at 6.0 GHz."
GCN 13642 table
GRB_name GRB120811C
GCN_number 13642
Detection_method Fermi GBM Det
t_trigger 15:34:55.090 UTC
Circular_text TITLE: GCN CIRCULAR NUMBER: 13642 SUBJECT: GCN for GRB 120811C DATE: 12/08/14 20:33:25 GMT FROM: Peter Jenke at MSFC Peter Jenke (MSFC/NPP) reports on behalf of the Fermi GBM Team: "At 15:34:55.09 UT on 11 August 2012, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 120811C (trigger 366392098 / 120811649) which was also detected by the Swift/BAT (Barthelmy et al. 2012, GCN 13622). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight is 133 degrees. The GBM light curve consists of a single pulse with a duration (T90) of about 14.3 s (50-300 keV). The time-averaged spectrum from T0-6.14 s to T0+10.24 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.71 +/- 0.20 and the cutoff energy, parameterized as Epeak, is 54 +/- 3 keV. The event fluence (10-1000 keV) in this time interval is (2.98 +/- 0.08)E-06 ergs/cm^2. The 1-sec peak photon flux measured starting from T0+3.072 s in the 10-1000 keV band is 5.9304 +/- 0.55 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."
GCN 13679 table
GRB_name GRB120811C
GCN_number 13679
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 13679 SUBJECT: GRB 120811C: optical observations DATE: 12/08/18 22:18:42 GMT FROM: Alexei Pozanenko at IKI, Moscow L. Elenin (KIAM), A. Volnova (SAI MSU), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of GRB 120811C (Barlow et al., GCN 13622) with 0.45-m telescope of ISON-NM observatory starting on Aug. 12 (UT) 03:25:07. We took several unfiltered images of 30 s exposures. The optical afterglow (Denisenko et al., GCN 13623) is marginally detected in co-added frames at coordinates (J2000) 13:18:43.98 +62:18:03.4 with uncertainty of 0.5 arcsec in both coordinates. A preliminary photometry of co-added frames is based on the USNO-B1.0 (R2) nearby stars is following: T_start, T0+, Exposure, OT, UL (3 sigma) (UT) mid, d (s) 03:25:07 0.5095 1800 21.5 +/-0.5 21.2
GCN 13693 table
GRB_name GRB120811C
GCN_number 13693
Detection_method Optical
Circular_text TITLE: GCN CIRCULAR NUMBER: 13693 SUBJECT: GRB 120811C: optical observations DATE: 12/08/20 15:14:34 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Litvinenko (UBAI), A. Volnova (SAI MSU), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of GRB 120811C (Barlow et al., GCN 13622) with 0.4-m telescope of ISON-Kitab observatory starting on Aug. 11 (UT) 15:53:49. We took several unfiltered images of 30 s exposures. The optical afterglow (Denisenko et al., GCN 13623) is clearly detected in single initial frames. A photometry of some co-added frames is based on the SDSS stars SDSS id RA Dec R J131912.45+621444.3 13 19 12,453 +62 14 44,35 16.63 J131815,89+621830,6 13 18 15,896 +62 18 30,67 16.64 is following: T_start, T0+, Exposure, OT, (UT) mid, d (s) 15:53:49 0.01392 4x30 17,90 +/-0.13 15:56:05 0.01569 5x30 17.95 +/-0.13 15:58:55 0.01841 10x30 18.20 +/-0.10 16:04:35 0.02356 15x30 18.45 +/-0.11 16:13:06 0.03145 25x30 18.40 +/-0.07