//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17904 SUBJECT: GRB 150607A: Swift detection of a burst with an optical counterpart DATE: 15/06/07 08:10:50 GMT FROM: David Palmer at LANL V. D'Elia (ASDC), L. Izzo (URoma/ICRA), J. A. Kennea (PSU), K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 07:55:09 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 150607A (trigger=642620). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 140.024, +68.442 which is RA(J2000) = 09h 20m 06s Dec(J2000) = +68d 26' 33" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multiply-peaked structure with a duration of about 50 sec. The peak count rate was ~3000 counts/sec (15-350 keV), at ~8 sec after the trigger. The XRT began observing the field at 07:57:20.5 UT, 130.9 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 139.9916, 68.4368 which is equivalent to: RA(J2000) = +09h 19m 57.98s Dec(J2000) = +68d 26' 12.5" with an uncertainty of 6.5 arcseconds (radius, 90% containment). This location is 46 arcseconds from the BAT onboard position, within the BAT error circle. The initial flux in the 2.5 s image was 4.64e-10 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 136 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 09:19:57.18 = 139.98825 DEC(J2000) = +68:26:10.2 = 68.43618 with a 90%-confidence error radius of about 0.75 arc sec. This position is 5.0 arc sec. from the center of the XRT error circle. The estimated magnitude is 18.06 with a 1-sigma error of about 0.15. No correction has been made for the expected extinction corresponding to E(B-V) of 0.06. Burst Advocate for this burst is V. D'Elia (delia AT asdc.asi.it). 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: 17905 SUBJECT: GRB 150607A: Enhanced Swift-XRT position DATE: 15/06/07 12:41:33 GMT FROM: Phil Evans at U of Leicester J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team. Using 1781 s of XRT Photon Counting mode data and 2 UVOT images for GRB 150607A, 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 = 139.98854, +68.43599 which is equivalent to: RA (J2000): 09h 19m 57.25s Dec (J2000): +68d 26' 09.6" 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. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17906 SUBJECT: GRB 150607A: Fermi GBM Detection DATE: 15/06/07 14:02:19 GMT FROM: Oliver Roberts at UCD/Fermi O.J. Roberts (UCD) reports on behalf of the Fermi GBM Team: "At 07:55:09.85 UT on the 7th of June 2015, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 150607A (trigger 455356512 / 150607330), which was also detected by Swift (D'Elia et al. 2015, GCN 17904). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight using this position is about 130 degrees. The GBM light curve shows several bright pulses over a duration (T90) of 31.8 s (50-300 keV). The time-averaged spectrum from T0-1.7 s to T0+30.1 s is well fit by power law function with an exponential high-energy cutoff. The power law index is -0.98 +/- 0.17 and the cutoff energy, parameterized as Epeak, is 137 +/- 22 keV. The event fluence (10-1000 keV) in this time interval is (4.4 +/- 0.4)E-06 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+6.8 s in the 10-1000 keV band is 6.8 +/- 0.5 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17907 SUBJECT: GRB 150607A: Swift-BAT refined analysis DATE: 15/06/07 22:51:34 GMT FROM: Scott Barthelmy at NASA/GSFC D. M. Palmer (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), V. D'Elia (ASDC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from recent telemetry downlinks, we report further analysis of BAT GRB 150607A (trigger #642620) (D'Elia, et al., GCN Circ. 17904). The BAT ground-calculated position is RA, Dec = 140.015, 68.436 deg, which is RA(J2000) = 09h 20m 03.6s Dec(J2000) = +68d 26' 10.3" with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 31%. The mask-weighted light curve shows multiple peaks starting at ~T-2 sec, the brightest peak at ~T+8 sec, and ending at ~T+40 sec. T90 (15-350 keV) is 26.3 +- 0.7 sec (estimated error including systematics). The time-averaged spectrum from T-0.19 to T+27.58 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.99 +- 0.41, and Epeak of 84.9 +- 40.1 keV (chi squared 40.9 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 2.3 +- 0.2 x 10^-6 erg/cm2 and the 1-sec peak flux measured from T+7.29 sec in the 15-150 keV band is 4.9 +- 0.5 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.59 +- 0.10 (chi squared 48.1 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/642620/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17908 SUBJECT: GRB 150607A: NOT optical observations DATE: 15/06/07 23:42:40 GMT FROM: Thomas Kruehler at Dark Cosmology Center T. Kruehler (ESO) & A. A. Djupvik (NOT) report on behalf of a larger collaboration: We observed the field of GRB 150607A (D'Elia et al., GCN 17904) using the Nordic Optical Telescope equipped with the ALFOSC camera. A short series of photometry in BVRI filters was taken starting at 2015-06-07 21:43UT. The optical afterglow (D'Elia et al., GCN 17094) of GRB 150607A is well detected in our images. We measure R = 21.6 +/- 0.2 mag at 13.76 hours after the trigger, calibrated against magnitudes of nearby stars from the USNO-B1 catalog. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17909 SUBJECT: GRB 150607A: Swift/UVOT Detection DATE: 15/06/08 00:28:17 GMT FROM: Lea Hagen at PSU L. M. Z. Hagen (PSU) and V. D'Elia (ASDC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 150607A 137 s after the BAT trigger (D'Elia et al., GCN Circ. 17904). A source consistent with the XRT position (Osborne et al. GCN Circ. 17905) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 09:19:57.20 = 139.98833 (deg.) Dec (J2000) = +68:26:10.3 = 68.43619 (deg.) with an estimated uncertainty of 0.44 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 137 286 146 18.10 +/- 0.07 white 628 1204 205 20.04 +/- 0.31 white 1358 7668 412 >20.55 v 118 128 9 16.71 +/- 0.35 v 678 7955 446 >19.02 b 604 7463 367 >19.65 u 348 598 245 18.88 +/- 0.27 u 753 7258 352 >19.37 uvw1 728 7053 352 >19.60 uvm2 1084 6848 313 >19.74 uvw2 654 7874 568 >20.30 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.07 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17910 SUBJECT: GRB 150607A: Swift-XRT refined Analysis DATE: 15/06/08 03:10:06 GMT FROM: Phil Evans at U of Leicester D.N. Burrows (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), A. Amaral-Rogers (U. Leicester), A. D'ai (INAF-IASFPA), A. Maselli (INAF-IASFPA) and V. D'Elia report on behalf of the Swift-XRT team: We have analysed 7.7 ks of XRT data for GRB 150607A (D'Elia et al. GCN Circ. 17904), from 118 s to 47.9 ks after the BAT trigger. The data comprise 44 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 Osborne et al. (GCN Circ. 17905). The light curve can be modelled with an initial power-law decay with an index of alpha=0.77 (+/-0.06), followed by a break at T+4216 s to an alpha of 1.11 (+0.26, -0.09). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.82 (+0.11, -0.10). The best-fitting absorption column is 2.2 (+/-0.4) x 10^21 cm^-2, in excess of the Galactic value of 5.7 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.0 x 10^-11 (5.1 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 2.2 (+/-0.4) x 10^21 cm^-2 Galactic foreground: 5.7 x 10^20 cm^-2 Excess significance: 6.5 sigma Photon index: 1.82 (+0.11, -0.10) If the light curve continues to decay with a power-law decay index of 1.11, the count rate at T+24 hours will be 0.020 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 7.8 x 10^-13 (1.0 x 10^-12) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00642620. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17911 SUBJECT: Konus-Wind observation of GRB 150607A DATE: 15/06/08 10:59:30 GMT FROM: Dmitry Svinkin at Ioffe Institute S. Golenetskii, R. Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, report: The long-duration GRB 150607A (Swift-BAT trigger #642620: D'Elia, et al., GCN 17904; Palmer, et al., GCN 17907; Fermi GBM detection: Roberts, GCN 17906) triggered Konus-Wind at T0=28509.211 s UT (07:55:09.211). The burst light curve shows a multipeak structure with a total duration of ~30 s. The emission is seen up to ~1 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB150607_T28509/ As observed by Konus-Wind, the burst had a fluence of 4.2(-0.8,+1.3)x10^-6 erg/cm2, and a 64-ms peak flux, measured from T0-0.222 s, of 1.2(-0.5,+0.6)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+33.024 s) is best fit in the 20 keV - 2 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -1.4(-0.3,+0.4) and Ep = 173(-57,+183) keV (chi2 = 61/62 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2 (chi2 = 60/61 dof) The spectrum near the maximum count rate (measured from T0+0.000 to T0+8.448 s) is best fit in the 20 keV - 2 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -1.4(-0.3,+0.4) and Ep = 152(-42,+108) keV (chi2 = 46/62 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2 (chi2 = 46/61 dof) All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17914 SUBJECT: GRB150607A: Discovery Channel Telescope Optical Observations DATE: 15/06/08 17:14:26 GMT FROM: Vicki Toy at UMD V. Toy (UMD), J. Capone (UMD), S.B. Cenko (NASA-GSFC), S. Veilleux (UMD), A. Cucchiara (NASA-GSFC), E. Troja (NASA-GSFC), and A. Kutyrev (NASA-GSFC) report on behalf of a larger collaboration: We observed the field of GRB150607A (Swift trigger 642620, D'Elia et al., GCN 17904) with the Large Monolithic Imager (LMI) on the 4.3m Discovery Channel Telescope (DCT) at Happy Jack, AZ from 2015/06/08 03:42 to 2015/06/08 04:35 UTC (starting 19.8 hours after the trigger). A source is clearly detected at the location of the optical afterglow in r', i', and z'. Using nearby point sources from USNO-B1.0 for calibration, we measure r' = 22.03 +/- 0.03. This magnitude is reported in AB magnitude and is not corrected for Galactic extinction in the direction of the GRB. Compared to NOT observations on 06/07 (Kruehler & Djupvik, GCN 17908) the afterglow has a decay index of ~ t^-1.1. We thank the staff of the Discovery Channel Telescope for assistance with these observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17915 SUBJECT: GRB150607A: AAO and CrAO optical observations DATE: 15/06/08 17:49:29 GMT FROM: Alexei Pozanenko at IKI, Moscow E. Mazaeva (IKI), R. Inasaridze (AAO), S. Nazarov (CrAO), Sh. Makandarashvili (AAO), A. Volnova (IKI), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the field of GRB 150607A (Swift trigger 642620, D'Elia et al., GCN 17904) with the AS-32 (0.7m) telescope of Abastumani Observatory (AAO) starting on June, 07 17:54:22, and with AZT-8 telescope of CrAO starting on June, 07 19:43:21. The afterglow of GRB 150607A (Kruehler et al., GCN 17908; Hagen et al., GCN 17909) is clearly detected in early observation in AAO. Preliminary photometry is following. telescope UT start t-T0 Filter Exp. OT Err. (mid, days) (s) AS-32 17:54:22 0.45669 None 44*120 21.20 0.1 AZT-8 19:43:21 0.49864 R 6*180 >19.4 (3sigma) Photometry is based on nearby USNO-B1.0 stars.