//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11918 SUBJECT: GRB 110411A: Swift detection of a burst DATE: 11/04/11 19:44:17 GMT FROM: Jamie A. Kennea at PSU/Swift-XRT D. Grupe (PSU), S. Campana (INAF-OAB), J. R. Cummings (NASA/UMBC), J. M. Gelbord (PSU), J. A. Kennea (PSU), C. B. Markwardt (NASA/GSFC), B. Sbarufatti (INAF-OAB/IASFPA), M. H. Siegel (PSU), E. Sonbas (GSFC/USRA/Adiyaman Univ.), R. L. C. Starling (U Leicester), C. A. Swenson (PSU) and T. N. Ukwatta (MSU) report on behalf of the Swift Team: At 19:34:11 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 110411A (trigger=451165). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 291.437, +67.732 which is RA(J2000) = 19h 25m 45s Dec(J2000) = +67d 43' 55" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a double-peaked structure with a duration of about 120 sec. The peak count rate was ~2000 counts/sec (15-350 keV), at ~5 sec after the trigger. The XRT began observing the field at 19:36:18.2 UT, 126.4 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source located at RA, Dec 291.43966, 67.71117 which is equivalent to: RA(J2000) = 19h 25m 45.52s Dec(J2000) = +67d 42' 40.2" with an uncertainty of 3.8 arcseconds (radius, 90% containment). This location is 75 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 (6.92 x 10^20 cm^-2, Kalberla et al. 2005), with an excess column of 5.4 (+3.77/-2.83) x 10^21 cm^-2 (90% confidence). The initial flux in the 2.5 s image was 1.26e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 135 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 0.10. Burst Advocate for this burst is D. Grupe (grupe AT astro.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.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11919 SUBJECT: GRB 110411A: MASTER optical observations DATE: 11/04/11 21:16:53 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs O. Gres, K.Ivanov, V.A.Poleshchuk, S.Yazev, N.M.Budnev, O.Chuvalaev Irkutsk State University E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, A.Belinski, N.Tyurina, N.Shatskiy, P.Balanutsa, V.V.Chazov, P.V.Kortunov, A.Kuznetsov, D.Zimnukhov, M. Kornilov, A.Kuznetsov, D.Zimnukhov, M. Kornilov, A.Sankovich Sternberg Astronomical Institute, Moscow State University A. Tlatov, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory V.Krushinski, I.Zalozhnich, T.Kopytova, A. Popov Ural State University, Kourovka V.Yurkov, Yu.Sergienko, D.Varda, I.Kudelina Blagoveschensk Educational State University, Blagoveschensk MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Tunka(Siberia) was pointed to the GRB110411A 19 sec s after notice time and 44 sec after GRB time at 2011-04-11 19:34:55.3 UT in two polarizations. On our first (10s exposure) set we haven`t found optical transient within SWIFT error-box (ra=19 25 45 dec=+67 43 48 r=0.050000). The 5-sigma upper limit has been about 17.5 mag Observations and data reduction is continued. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11920 SUBJECT: GRB 110411A: Enhanced Swift-XRT position DATE: 11/04/11 23:56:36 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 2358 s of XRT Photon Counting mode data and 2 UVOT images for GRB 110411A, 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 = 291.44219, +67.71167 which is equivalent to: RA (J2000): 19h 25m 46.13s Dec (J2000): +67d 42' 42.0" 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: 11921 SUBJECT: GRB 110411A, Swift-BAT refined analysis DATE: 11/04/12 00:05:34 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), D. Grupe (PSU), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-61 to T+242 sec from the recent telemetry downlink, we report further analysis of BAT GRB 110411A (trigger #451165) (Grupe, et al., GCN Circ. 11918). The BAT ground-calculated position is RA, Dec = 291.427, 67.706 deg which is RA(J2000) = 19h 25m 42.5s Dec(J2000) = +67d 42' 21.0" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 71%. The burst had multiple peaks with gradual rise and fall. The two largest peaks were centered around T+5 sec and T+60 sec. T90 (15-350 keV) is 80.3 +- 5.2 sec (estimated error including systematics). The time-averaged spectrum from T-11.9 to T+86.3 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.51 +- 0.31, and Epeak of 41.0 +- 8.1 keV (chi squared 49.70 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 3.3 +- 0.2 x 10^-06 erg/cm2 and the 1-sec peak flux measured from T+4.73 sec in the 15-150 keV band is 1.3 +- 0.2 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.05 +- 0.07 (chi squared 59.73 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/451165/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11923 SUBJECT: GRB 110411A : Xinglong TNT OT candidate DATE: 11/04/12 09:03:58 GMT FROM: L.P. Xin at NAOC L.P. Xin, Z. X. Ling, Y.L. Qiu, J.Y. Wei, J. Wang, J.S. Deng, C. Wu, X. H. Han on behalf of EAFON report: We began to observe GRB110411A ( Grope et al., GCN 11918) with Xinglong TNT telescope at 19:35:32 (UT), 81 sec after the burst. A series of White and R-band images were obtained. With the combination of all R-band images of 37*60 sec exposure time, we detected an new source nearby the errorbox of X-ray counterpart ( Goad et al., GCN 11920 ). The coordinates of new source are: Ra: 19:25:45.65 Dec: 67:42:39.1 Epoch: J2000 The uncertainty of the coordinates is about 1 arc. The brightness of this source is estimated to be about 21 +/- 0.2 mag in the R band, at the mean time of 38 min after the burst, comparing to an USNO B1.0 R2 reference star, of which the coordinates are 19:25:52.432 +67:43:44.07 J2000 R2=16.18mag. We proposed that the new source be the optical counterpart of GRB 110411A. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11924 SUBJECT: GRB 110411A: MASTER prompt and follow-up optical limits DATE: 11/04/12 11:00:43 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs O. Gres, K.Ivanov, V.A.Poleshchuk, S.Yazev, N.M.Budnev, O.Chuvalaev Irkutsk State University E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, A.Belinski, N.Tyurina, N.Shatskiy, P.Balanutsa, V.V.Chazov, P.V.Kortunov, A.Kuznetsov, D.Zimnukhov, M. Kornilov, A.Kuznetsov, D.Zimnukhov, M. Kornilov, A.Sankovich Sternberg Astronomical Institute, Moscow State University A. Tlatov, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory V.Krushinski, I.Zalozhnich, T.Kopytova, A. Popov Ural State University, Kourovka V.Yurkov, Yu.Sergienko, D.Varda, I.Kudelina Blagoveschensk Educational State University, Blagoveschensk MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Tunka(Siberia) was pointed to the GRB110411A (Grupe et al., GCN 11918) 19 sec s after notice time and 44 sec after GRB time at 2011-04-11 19:34:55.3 UT in two polarizations. A series of Polarization, White and R-band images were obtained. We have not found OT at Xinglong TNT OT candidate position (Xin et al., GCN Circ 11923). The results from two tubes are: (GRB Time = 2011-04-11 19:34:11 UT) Date time Exp.time Limit Filt.(W-white) UT (s) (5-sigma) 2011-04-11 19:34:55 10 17.4 W 2011-04-11 19:34:55 10 18.0 W 2011-04-11 19:35:23 10 14.8 P/ 2011-04-11 19:35:23 10 15.4 P\ 2011-04-11 19:35:50 20 15.5 P/ 2011-04-11 19:35:51 20 16.0 P\ 2011-04-11 19:36:29 30 16.0 P/ 2011-04-11 19:36:29 30 16.5 P\ 2011-04-11 19:37:17 40 16.0 P/ 2011-04-11 19:37:18 40 16.7 P/ 2011-04-11 19:38:14 50 16.3 P\ 2011-04-11 19:38:14 50 16.9 P/ 2011-04-11 19:39:22 60 16.5 P\ 2011-04-11 19:39:22 60 17.0 P/ 2011-04-11 19:40:39 80 16.6 P\ 2011-04-11 19:40:39 80 17.2 P/ 2011-04-11 19:42:14 3790 19.4 P\ 2011-04-11 19:42:14 100 17.0 P/ 2011-04-11 19:42:15 3970 18.9 P\ 2011-04-11 19:42:15 100 17.7 P/ 2011-04-11 19:44:10 120 17.4 P\ 2011-04-11 19:44:11 120 17.4 P/ 2011-04-11 19:46:26 150 17.8 P\ 2011-04-11 19:46:26 150 17.7 P/ 2011-04-11 19:49:11 180 18.1 P\ 2011-04-11 19:49:12 180 17.9 P/ 2011-04-11 19:52:30 180 18.0 P\ 2011-04-11 19:52:30 180 17.9 P/ 2011-04-11 19:55:46 180 18.1 P\ 2011-04-11 19:55:46 180 18.0 P/ 2011-04-11 19:59:02 180 18.1 P\ 2011-04-11 19:59:02 180 18.1 P/ 2011-04-11 20:02:17 180 18.1 P\ 2011-04-11 20:02:18 180 18.1 P/ 2011-04-11 20:05:33 180 18.1 P\ 2011-04-11 20:05:34 180 18.1 P/ 2011-04-11 20:08:49 180 18.0 P\ 2011-04-11 20:08:49 180 18.0 P/ 2011-04-11 20:12:06 180 18.0 P\ 2011-04-11 20:12:06 180 18.0 P/ 2011-04-11 20:15:23 180 18.1 P\ 2011-04-11 20:15:24 180 18.0 P/ 2011-04-11 20:18:40 180 18.1 P\ 2011-04-11 20:18:41 180 18.0 P/ 2011-04-11 20:21:57 180 18.1 P\ 2011-04-11 20:21:58 180 18.0 P/ 2011-04-11 20:25:14 180 18.0 P\ 2011-04-11 20:25:14 180 18.0 P/ 2011-04-11 20:28:38 180 18.1 P\ 2011-04-11 20:28:40 180 18.0 P/ 2011-04-11 20:31:56 180 18.1 P\ 2011-04-11 20:31:57 180 18.0 P/ 2011-04-11 20:35:13 180 18.0 P\ 2011-04-11 20:35:13 180 17.9 P/ 2011-04-11 20:38:32 180 18.1 P\ 2011-04-11 20:38:32 180 17.9 P/ 2011-04-11 20:41:48 180 17.8 P\ 2011-04-11 20:41:48 180 17.9 P/ 2011-04-11 20:45:04 180 17.8 P\ 2011-04-11 20:45:04 180 17.9 P/ 2011-04-11 20:48:20 180 17.8 P\ 2011-04-11 20:48:20 180 17.7 P/ 2011-04-11 20:51:45 180 17.7 P\ 2011-04-11 20:51:46 180 17.7 P/ 2011-04-11 20:59:09 180 19.0 W 2011-04-11 20:59:09 900 19.4 W 2011-04-11 20:59:09 180 18.8 R 2011-04-11 20:59:09 900 19.2 R 2011-04-11 21:02:42 180 18.7 W 2011-04-11 21:02:43 180 18.8 R 2011-04-11 21:06:52 180 18.5 W 2011-04-11 21:06:52 180 18.5 R 2011-04-11 21:10:28 180 18.2 W 2011-04-11 21:10:28 180 18.3 R 2011-04-11 21:14:04 180 18.0 W 2011-04-11 21:14:04 180 18.0 R The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11925 SUBJECT: GRB 110411A: Swift/UVOT Upper Limits DATE: 11/04/12 11:59:12 GMT FROM: Paul Kuin at MSSL N.P.M. Kuin (MSSL/UCL) and D. Grupe (PSU) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 110411A 135 s after the BAT trigger (Grupe et al., GCN Circ. 11918). No optical afterglow consistent with the XRT (Goad et al., GCN Circ. 11920) or the Xinglong (Xin et al., GCN Circ. 11923) positions is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 135 285 147 >21.3 u_FC 347 597 246 >20.4 white 135 7753 883 >22.2 v 677 8164 607 >19.9 b 603 7548 586 >21.1 u 347 7343 637 >20.4 w1 726 7139 391 >20.2 m2 701 8326 508 >20.1 w2 653 7959 607 >20.9 The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.10 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11927 SUBJECT: GRB 110411A: Swift-XRT refined Analysis DATE: 11/04/12 16:26:11 GMT FROM: Dirk Grupe at PSU/Swift-XRT D. Grupe (PSU) reports on behalf of the Swift-XRT team: We have analyzed 11 ks of XRT data for GRB 110411A (Grupe et al. GCN Circ. 11918), from 117 s to 37.2 ks after the BAT trigger. The data comprise 64 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 Goad et al. (GCN. Circ 11920). The light curve can be modeled with a series of power-law decays. The initial decay index is alpha=6.0 (+/-0.6). At T+230 s the decay flattens to an alpha of 0.58 (+0.11, -0.12) before breaking again at T+4446 s to a final decay with index alpha=1.39 (+0.27, -0.24). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.93 (+0.23, -0.21). The best-fitting absorption column is 1.02 (+0.14, -0.12) x 10^22 cm^-2, in excess of the Galactic value of 6.9 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 4.0 x 10^-11 (2.3 x 10^-10) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.02 (+0.14, -0.12) x 10^22 cm^-2 Galactic foreground: 6.9 x 10^20 cm^-2 Excess significance: 13.5 sigma Photon index: 2.93 (+0.23, -0.21) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00451165. With an excess absorption column density of 9.5 x 10^21 cm^-2 following the relation in Grupe et al. (2007, AJ, 133, 2216) the estimated maximum redshift of the afterglow is z < 1.0. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11928 SUBJECT: GRB 110411A: optical limits from OSN DATE: 11/04/12 18:26:34 GMT FROM: Martin Jelinek at Inst.Astrophys.Andalucia,Granada A. Sota, J. Gorosabel and M. Jelinek (IAA-CSIC), report on behalf of a larger collaboration. "We have observed the XRT error circle (Goad et al. GCNC 11920) of GRB 110411A (Grupe et al. GCNC 11918) with the 1.5m telescope of Observatorio de Sierra Nevada, Granada, Spain. The observations were carried out on April 12.06606-12.12741 UT (6.01-7.49 hours post trigger) in the R and I bands with an exposure time of 8x300s in each band. No object is detected within the XRT error circle down to R < 23.5 and I < 22.4, calibrated against USNO B1.0". //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11930 SUBJECT: GRB 110411A: PAIRITEL NIR Upper Limits DATE: 11/04/12 22:35:19 GMT FROM: Adam Morgan at U.C. Berkeley A. N. Morgan, A. Cucchiara, and J. S. Bloom (UC Berkeley) report: We observed the field of GRB 110411A (Grupe et al., GCN 11918) with the 1.3m PAIRITEL located at Mt. Hopkins, Arizona. Observations began at 2011-04-12 09:53:13 UT, ~14.3 hours after the Swift Trigger. In mosaics (effective exposure time of 1.22 hours) taken simultaneously in the J, H, and Ks filters, we do not detect any source at the optical afterglow candidate location (Xin et al., GCN 11923). The preliminary photometry yields: post burst t_mid (hr) exp.(hr) filt U. Limit (3 sig) 15.37 1.22 J > 18.7 15.37 1.22 H > 18.0 15.37 1.22 H > 16.6 All magnitudes are given in the Vega system, calibrated to 2MASS. No correction for Galactic extinction has been made to the above reported values.