//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14703 SUBJECT: GRB 130527A: Swift detection of a bright burst DATE: 13/05/27 14:31:45 GMT FROM: David Palmer at LANL B.P. Gompertz (U Leicester), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), M. M. Chester (PSU), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), A. Y. Lien (NASA/GSFC/ORAU), F. E. Marshall (NASA/GSFC), C. J. Mountford (U Leicester), C. Pagani (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 14:21:30 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 130527A (trigger=556753). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 309.279, -24.728 which is RA(J2000) = 20h 37m 07s Dec(J2000) = -24d 43' 39" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex peak structure with a duration of at least 20 sec. The peak count rate was ~25000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 14:23:15.4 UT, 105.2 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 309.2749, -24.7244 which is equivalent to: RA(J2000) = +20h 37m 5.98s Dec(J2000) = -24d 43' 27.8" with an uncertainty of 5.0 arcseconds (radius, 90% containment). This location is 18 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 2.88e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 113 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 0.04. Burst Advocate for this burst is B.P. Gompertz (bpg6 AT le.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.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14704 SUBJECT: GRB 130527A: Prompt enhanced Swift-XRT position DATE: 13/05/27 15:12:30 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Using promptly downlinked XRT event data for GRB 130527A, we find an enhanced XRT position of the afterglow: RA, Dec: 309.2762, -24.7246 which is equivalent to: RA (J2000) = 20 37 06.28 Dec (J2000) = -24 43 28.6 with an uncertainty of 2.0 arcseconds (radius, 90% confidence). Analysis of the promptly available data is online at http://www.swift.ac.uk/sper/556753. Position enhancement is is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14705 SUBJECT: GRB 130527A: Enhanced Swift-XRT position DATE: 13/05/27 21:08:38 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 872 s of XRT Photon Counting mode data and 1 UVOT images for GRB 130527A, 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 = 309.27631, -24.72515 which is equivalent to: RA (J2000): 20h 37m 6.32s Dec (J2000): -24d 43' 30.6" 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: 14706 SUBJECT: GRB 130527A: BOOTES-2 & 3.5m CAHA opt/nIR observations DATE: 13/05/28 06:34:33 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia A. J. Castro-Tirado (IAA-CSIC), J. Gorosabel (IAA-CSIC, UPV-EHU), A. Guijarro (CAHA) and M. Jelínek (IAA-CSIC), on behalf of a larger collaboration, report: "Following the detection of GRB 130527A by Swift (Gompertz et al. GCNC 14703), follow-up observations have been conducted with the 0.6m TELMA telescope (+ COLORES, i'-band) at the BOOTES-2 station in Málaga and with the 3.5m CAHA (+ Omega2000, zYJHK) at the German-Spanish Calar Alto Observatory. Data was gathered starting at 2:30 UT (i.e. ~12.1 hr post burst), at high airmass and with the moon only 11 degrees away. At the position of the X-ray afterglow (Evans et al. GCNC 14705), no optical/nIR source is detected down to J ~ 20. Further data analysis is ongoing." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14707 SUBJECT: GRB 130527A: Swift-XRT refined Analysis DATE: 13/05/28 14:32:06 GMT FROM: Phil Evans at U of Leicester V. Mangano (INAF-IASFPA), A. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), J.A. Kennea (PSU), M.C. Stroh (PSU), D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Pagani (U. Leicester) and B.P. Gompertz report on behalf of the Swift-XRT team: We have analysed 5.9 ks of XRT data for GRB 130527A (Gompertz et al. GCN Circ. 14703), from 94 s to 18.3 ks after the BAT trigger. The data comprise 203 s in Windowed Timing (WT) mode (the first 10 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 14704). The late-time light curve (from T0+4.9 ks) can be modelled with a power-law decay with a decay index of alpha=1.15 (+0.24, -0.23). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.70 (+/-0.09). The best-fitting absorption column is 2.4 (+/-0.3) x 10^21 cm^-2, in excess of the Galactic value of 3.7 x 10^20 cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index of 1.67 (+0.16, -0.15) and a best-fitting absorption column of 1.5 (+/-0.5) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.5 x 10^-11 (5.5 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.5 (+/-0.5) x 10^21 cm^-2 Galactic foreground: 3.7 x 10^20 cm^-2 Excess significance: 3.9 sigma Photon index: 1.67 (+0.16, -0.15) If the light curve continues to decay with a power-law decay index of 1.15, the count rate at T+24 hours will be 5.7 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.6 x 10^-13 (3.1 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/00556753. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14708 SUBJECT: GRB 130527A: Swift-BAT refined analysis DATE: 13/05/28 14:55:43 GMT FROM: Scott Barthelmy at NASA/GSFC W. H. Baumgartner (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), B.P. Gompertz (U Leicester), H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/GSFC/ORAU), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), 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-700 to T+302 sec from recent telemetry downlinks, we report further analysis of BAT GRB 130527A (trigger #556753) (Gompertz, et al., GCN Circ. 14703). The BAT ground-calculated position is RA, Dec = 309.282, -24.726 deg, which is RA(J2000) = 20h 37m 07.6s Dec(J2000) = -24d 43' 35.1" with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 10%. The mask-weighted light curve shows many overlapping peakst starting at ~T-10 sec, peaking at ~T+1 sec, and ending at ~T+170 sec. T90 (15-350 keV) is 44 +- 16 sec (estimated error including systematics). The time-averaged spectrum from T-2.9 to T+90.7 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.25 +- 0.06. The fluence in the 15-150 keV band is 1.2 +- 0.04 x 10^-5 erg/cm2. The 1-sec peak photon flux measured from T+0.06 sec in the 15-150 keV band is 20.1 +- 1.4 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/556753/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14709 SUBJECT: GRB 130527A: RATIR Optical and NIR Observations DATE: 13/05/28 16:17:12 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 (UCSC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), José A. de Diego (UNAM), Leonid Georgiev (UNAM), Jesús González (UNAM), Carlos Román-Zúńiga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report: We observed the field of GRB 130527A (Gompertz, et al., GCN 14703) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir from 2013/05 28.35 to 2013/05 28.47 UTC (18.13 to 20.91 hours after the BAT trigger), obtaining a total of 1.97 hours exposure in the r' and i' bands and 0.73 hours exposure in the Z, Y, J, and H bands. For a source within the Swift-XRT error circle (Evans, et al., GCN 14705), in comparison with USNO-B1 and 2MASS, we obtain the following upper limits (3-sigma): r' > 21.9 i' > 22.3 Z > 20.7 Y > 20.6 J > 20.6 H > 20.3 These magnitudes are in the AB system and not corrected for Galactic extinction in the direction of the GRB. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14710 SUBJECT: GRB 130527A: NOT optical counterpart DATE: 13/05/28 16:42:36 GMT FROM: Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst Z. Cano (U. Iceland), D. Malesani (DARK), N. R. Tanvir (U. Leicester), D. Xu (DARK/NBI), T. Kangas (U. Turku), and J. Kajava (NOT) report on behalf of a larger collaboration: On 2013 May 28, beginning at 03:55 UT, we observed the field of GRB 130527A (Gompertz et al., GCN 14703) with the Nordic Optical Telescope (NOT) equipped with the ALFOSC instrument using the z filter, for a total exposure time of 40 minutes. Observations were carried out at moderate airmass, with the bright Moon only 18 deg away, at a mean epoch of May 28.179 UT (13.94 hr after the GRB). Inside the refined XRT error circle (Evans et al., GCN 14705; see also http://www.swift.ac.uk/xrt_positions/) we do not detect any bright source, but there is a faint, apparently extended object with magnitude z = 21.4 +- 0.2. The limiting magnitude for an isolated object in our coadded image is z = 22.1. Calibration has been derived using two stars in the USNO B1 catalog (0652-0853265 and 0652-0853288), and converting their R2 and I magnitudes into z using the transformation equations from Jordi et al. (2006, A&A, 460, 339). The source could be the GRB host. A snapshot showing our coadded image can be found at the URL http://www.astro.ku.dk/~malesani/GRB/130527A/GRB130527A_finder_NOT.jpg //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14715 SUBJECT: GRB 130527A: Swift/UVOT Upper Limits DATE: 13/05/29 00:50:04 GMT FROM: Margaret Chester at PSU M. M. Chester (PSU) and B. P. Gompertz (U Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 130527A 113 s after the BAT trigger (Gompertz et al., GCN Circ. 14703). No optical afterglow consistent with the XRT position (Evans et al. GCN Circ. 14705) 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) exposures and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 113 263 147 >21.2 white 113 1547 392 >21.1 white 4949 12020 623 >21.8 v 655 1596 117 >18.7 v 5359 5559 197 >19.5 b 581 1693 114 >20.2 b 6179 11579 906 >21.3 u_FC 325 575 246 >20.3 u 325 1671 343 >20.2 u 5974 18261 1072 >21.1 w1 704 1646 97 >19.8 w1 5769 17356 1082 >21.1 m2 680 1621 117 >20.0 m2 5564 5764 197 >19.8 w2 630 1572 117 >20.6 w2 5154 5354 197 >20.2 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.04 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14720 SUBJECT: Konus-Wind observation of GRB 130527A DATE: 13/05/29 14:11:48 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report: The long-duration intense hard-spectrum GRB 130527A (Swift-BAT trigger 556753: Gompertz et al., GCN 14703;) Baumgartner et al., GCN 14708) triggered Konus-Wind at T0=51688.300s UT (14:21:28.300). The light curve shows a bright hard multi-peaked emission complex from ~T0 s to ~T0+10s, followed by the weaker and softer emission out to ~T0+40s. The emission is seen up to 10 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB130527_T51688/ As observed by Konus-Wind, the burst had a fluence of (1.1 ± 0.05)x10-4 erg/cm2, and a 64-ms peak flux, measured from T0+3.200s, of (5.0 ± 0.3)x10-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum (measured from T0 to T0+38.656 s) is best fit in the 50 keV - 15 MeV range by the cutoff power law model with the following parameters: the photon index alpha = -1.04 ± 0.04, the peak energy Ep = 1380 ± 120 keV, chi2 = 96/90 dof. The spectrum at the maximum count rate (measured from T0+0.256 to T0+5.888 s) is best fit in the 50 keV - 15 MeV range by the GRB (Band) function with the following model parameters: by the cutoff power law model with the following parameters: the photon index alpha = -0.97 ± 0.04, the peak energy Ep = 1429 ± 84 keV, chi2 = 72/79 dof. All the quoted results are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14727 SUBJECT: GRB 130527A: Suzaku WAM observation of the prompt emission DATE: 13/05/30 11:28:01 GMT FROM: Makoto Tashiro at Saitama U/Swift H. Ueno, M. Tashiro, Y. Terada, T. Yasuda, Y. Ishida, S. Sugimoto (Saitama U.), M. Ohno, K. Takaki, T. Kawano, R. Nakamura, S. Furui, Y. Fukazawa (Hiroshima U.), M. Yamauchi, N. Ohmori, M. Akiyama (Univ. of Miyazaki), K. Yamaoka (Nagoya U.), S. Sugita (Ehime U.), Y. E. Nakagawa, M. Kokubun, T. Takahashi (ISAS/JAXA), W. Iwakiri(RIKEN), Y. Hanabata (ICRR), Y. Urata (NCU), K. Nakazawa, K. Makishima (Univ. of Tokyo) on behalf of the Suzaku WAM team, report: The bright, long GRB 130527A (Swift-BAT detection: W. H. Baumgartner, et al. , GCN 14708) triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at UT 14:21:27.030(=T0). The observed light curve shows a multi-peaked structure starting at T0-0.5 s, ending at T0+13 s with a duration (T90) of about 7.4 seconds. The fluence in 100 - 1000 keV was 5.26 (-0.36, +0.39) *10^-5 erg/cm^2. The 1-s peak flux measured from T0+4.5 s was 20.26 (-0.92, +1.12) photons/cm^2/s in the same energy range. Preliminary result shows that the time-averaged spectrum from T0-1 s to T0+13 s is well fitted by a GRB Band model as follows. the low-energy photon index alpha: -0.87 (-0.13, +0.10), the high-energy photon index beta: -2.68 (-0.36, +0.14), and the peak energy Epeak: 1426 (-123, +221) keV, (chi^2/d.o.f = 36.3/28). Due to the brightness of this burst, a 3% systematic error was added for low energy channels. All the quoted errors are at statistical 90% confidence level. The light curves for this burst are available at: http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html