//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14620 SUBJECT: GRB 130511A: Swift detection of a burst with an optical counterpart DATE: 13/05/11 11:42:24 GMT FROM: David Palmer at LANL H. A. Krimm (CRESST/GSFC/USRA), D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 11:30:47 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 130511A (trigger=555600). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 196.639, +18.698 which is RA(J2000) = 13h 06m 33s Dec(J2000) = +18d 41' 51" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single short peak of duration ~0.5 sec followed by a 10-second tail. The peak count rate was ~3000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 11:31:58.9 UT, 71.6 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 196.64698, 18.70893 which is equivalent to: RA(J2000) = 13h 06m 35.28s Dec(J2000) = +18d 42' 32.1" with an uncertainty of 3.6 arcseconds (radius, 90% containment). This location is 47 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 (2.08 x 10^20 cm^-2, Kalberla et al. 2005), with an excess column of 2.5 (+1.47/-1.33) x 10^21 cm^-2 (90% confidence). UVOT took a finding chart exposure of 150 seconds with the White filter starting 74 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 13:06:34.96 = 196.64567 DEC(J2000) = +18:42:36.0 = 18.70999 with a 90%-confidence error radius of about 0.64 arc sec. This position is 7.0 arc sec. from the center of the XRT error circle. The estimated magnitude is 19.18 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 H. A. Krimm (krimm AT milkyway.gsfc.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.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14621 SUBJECT: GRB 130511A: Gemini-North Redshift DATE: 13/05/11 13:17:16 GMT FROM: Antonino Cucchiara at UCSC/UCO Lick A. Cucchiara (UCSC) and N. R. Tanvir (U. Leicester) report on behalf of a larger collaboration: On May 11.511 UT (~45 minutes after the Swift trigger) we observed the optical counterpart of GRB 130511A (Krimm et al. GCN 14620) with the GMOS spectrograph mounted on the Gemini-North telescope. The observation consists of 2x900s exposures using the B600 grating and covers the 5100-7900 Angstroms wavelength range. The resulting spectrum presents several absorption lines, including FeII(2344,2382,2374,2600), FeII*(2338,2349), FeI2463, MnII(25762594), MgII doublet (2796,2803A), and MgI2853 at the common redshift of z=1.3033. We therefore propose this as the redshift of GRB 130511A. We thank the Gemini staff for performing this observation, in particular Tom Geballe. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14622 SUBJECT: GRB 130511A: Enhanced Swift-XRT position DATE: 13/05/11 14:20:30 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 1521 s of XRT Photon Counting mode data and 1 UVOT images for GRB 130511A, 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 = 196.64526, +18.70977 which is equivalent to: RA (J2000): 13h 06m 34.86s Dec (J2000): +18d 42' 35.2" 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: 14623 SUBJECT: GRB 130511A: Upper limit by Xinglong TNT optical observation DATE: 13/05/11 15:14:12 GMT FROM: L.P. Xin at NAOC L. P. Xin, J. Y. Wei, Y. L. Qiu, J. Wang, J. S. Deng, C. Wu, X. H. Han report on behalf of EAFON team: We began to observe the field of GRB 130511A (Krimm et al. GCN 14620) using 80cm TNT telescope located at Xinglong observatory, China, at 41.9 min after the burst on 12:12:41 UT, May 11th, 2013. 15*300sec R-band images was obtained. The reported optical counterpart (Krimm et al. GCN 14620; Cucchiara et a. GCN 14621) was not detected in all single images and the combined image, down to the upper limit of R~19.6 mag calibrated by USNO B1.0 R2 mag, at the mean time of 62.3 min after the trigger time. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14624 SUBJECT: GRB 130511A, Swift-BAT refined analysis DATE: 13/05/11 21:27:10 GMT FROM: Hans Krimm at NASA-GSFC M. Stamatikos (OSU), 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/GSFC/ORAU), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU),T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-240 to T+950 sec from the recent telemetry downlink, we report further analysis of BAT GRB 130511A (trigger #555600) (Krimm, et al., GCN Circ. 14620). The BAT ground-calculated position is RA, Dec = 196.654, 18.709 deg which is RA(J2000) = 13h 06m 36.9s Dec(J2000) = +18d 42' 33.7" with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 57%. The mask-weighted light curve shows an initial sharp double-peak at T0 of duration ~0.5 seconds, transitioning to a FRED-like decay lasting ~5 seconds, after which the light curve returns to baseline. T90 (15-350 keV) is 5.43 +- 2.22 sec (estimated error including systematics). The time-averaged spectrum from T-0.07 to T+6.03 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.35 +- 0.31. The fluence in the 15-150 keV band is 2.2 +- 0.4 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T-0.09 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/555600/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14625 SUBJECT: GRB 130511A: MITSuME Okayama upper limits DATE: 13/05/11 23:20:56 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 MITSuME and OISTER collaboration: We observed the field of GRB 130511A (Krimm et al., GCNC 14620) 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 2013-05-11 12:01:00 UT (~30 min after the burst). We did not find any new point source within the enhanced XRT error circle (Osborne et al., GCNC 14622) in all the three bands. 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 ----------------------------------------------------- 0.16126 15:23:00 5940.0 >20.7 >20.7 >19.8 ----------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14626 SUBJECT: GRB 130511A: Kanata/HOWPol optical observation DATE: 13/05/12 04:34:23 GMT FROM: Koji Kawabata at HASC,Hiroshima U K. Takaki, K. Kawaguchi, K. S. Kawabata, M. Ohno and M. Yoshida (Hiroshima Univ.) report on behalf of Kanata team: We performed optical observations of GRB 130511A (Krimm et al., GCN 14620) with HOWPol attached to the 1.5-m Kanata telescope at Higashi-Hiroshima Observatory, Japan. The observation started at 11:32 UT on 2013 May 11 with imaging-polarimetry mode, followed by observation with imaging mode after 12:10 UT. We detected the optical afterglow of the GRB. Photometric results are shown below. We calibrated the Rc magnitude using USNO-B1.0 R2 magnitudes of nearby stars. Our result seems to be consistent with the brightness upper-limits reported in Xin et al. (GCN 14623) and Kuroda et al. (GCN 14625). The decline rate between these two epochs can be approximated by a single power-law with an index of -0.7. Mid time from Total Exp Filter Magnitude trigger (s) (s) ------------------------------------------------- 2571 300x2 Rc 20.0+-0.1 8768 300x2 Rc 21.0+-0.2 ------------------------------------------------- This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14627 SUBJECT: GRB 130511A: Swift-XRT refined Analysis DATE: 13/05/12 07:42:06 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester), B.P. Gompertz (U. Leicester), V. D'Elia (ASDC), A. Maselli (INAF-IASFPA), V. Mangano (INAF-IASFPA), M.C. Stroh (PSU), D.N. Burrows (PSU), J.A. Kennea (PSU), J.P. Osborne (U. Leicester) and H.A. Krimm report on behalf of the Swift-XRT team: We have analysed 8.4 ks of XRT data for GRB 130511A (Krimm et al. GCN Circ. 14620), from 57 s to 36.5 ks after the BAT trigger. The data comprise 8 s in Windowed Timing (WT) mode (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 14622). The light curve can be modelled with a power-law decay with a decay index of alpha=0.99 (+/-0.04). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.03 (+0.20, -0.19). The best-fitting absorption column is 1.1 (+0.5, -0.4) x 10^21 cm^-2, in excess of the Galactic value of 2.1 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 3.6 x 10^-11 (4.8 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.1 (+0.5, -0.4) x 10^21 cm^-2 Galactic foreground: 2.1 x 10^20 cm^-2 Excess significance: 3.5 sigma Photon index: 2.03 (+0.20, -0.19) If the light curve continues to decay with a power-law decay index of 0.99, the count rate at T+24 hours will be 2.6 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 9.4 x 10^-14 (1.2 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/00555600. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14628 SUBJECT: GRB130511A: SOAO Optical Observation DATE: 13/05/12 15:16:58 GMT FROM: Myungshin Im at Seoul Nat U M. Im (CEOU/SNU), H.-I. Sung (KASI), & Y. Urata (NCU) on behalf of a larger collaboration We observed GRB 130511A (Krimm et al., GCN 14620) in BVRI filters using a 0.6m telescope at the Sobaeksan Optical Astronomy Observatory (SOAO), starting at 76min after the BAT alert. In stacked images of 6 x 300sec exposures, we identify the optical afterglow with the following magnitude (Cucchiara et al. GCN 14621; Takaki et al. GCN 14626), calibrated against a USNO-B1 star in the vicinity. T(mid, UT) Mag 05-11 13:50:12 R=20.78 +- 0.13 The afterglow is detected in the other bands, but at a lower S/N. We thank the staffs at SOAO for performing the observation. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14652 SUBJECT: GRB 130511A: SSO 2.3m observation DATE: 13/05/15 02:34:36 GMT FROM: Fang Yuan at ANU F. Yuan, M. Childress, S. Rapoport, B. Schmidt, M. Dopita (Australian National University) and J. Scharwachter (Observatoire de Paris) We observed the field of GRB 130511A (Krimm et al., GCN 14620) using the Wide Field Spectrograph (WiFeS) on the ANU 2.3m. Three 900s integration at resolution R=3000, covering 540 - 950nm, were obtained starting at 2013-05-11 12:03 UTC, ~32 minutes after the Swift trigger. Spectral photometry of the sky-subtracted data cube was carried out in a 6" diameter aperture. Compared to a nearby field star, we measure the optical afterglow to be at r ~ 20.2 and i ~ 20.1 at a mean time of ~ 1 hr after the burst. We thank Tiantian Yuan, Fred Vogt and Rebecca Davis for performing this observation.