Gamma-ray Burst 160611A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN/BACODINE POSITION NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sat 11 Jun 16 21:40:53 UT
  NOTICE_TYPE:     Swift-BAT GRB Position
  TRIGGER_NUM:     690598,   Seg_Num: 0
  GRB_RA:          164.438d {+10h 57m 45s} (J2000),
                   164.579d {+10h 58m 19s} (current),
                   164.008d {+10h 56m 02s} (1950)
  GRB_DEC:         -70.395d {-70d 23' 40"} (J2000),
                   -70.483d {-70d 28' 58"} (current),
                   -70.127d {-70d 07' 36"} (1950)
  GRB_ERROR:       3.00 [arcmin radius, statistical only]
  GRB_INTEN:       4100 [cnts]    Image_Peak=175 [image_cnts]
  TRIGGER_DUR:     1.024 [sec] 
  TRIGGER_INDEX:   146     E_range: 25-100 keV
  BKG_INTEN:       26542 [cnts]
  BKG_TIME:        78015.59 SOD {21:40:15.59} UT
  BKG_DUR:         8 [sec]
  GRB_DATE:        17550 TJD;   163 DOY;   16/06/11
  GRB_TIME:        78034.41 SOD {21:40:34.41} UT
  GRB_PHI:         -151.76 [deg]
  GRB_THETA:        41.88 [deg]
  SOLN_STATUS:     0x3
  RATE_SIGNIF:     11.31 [sigma]
  IMAGE_SIGNIF:    7.82 [sigma]
  MERIT_PARAMS:     +1  +0  +0  +0  +2  -2  +0  +1 +33  +0 
  SUN_POSTN:        80.62d {+05h 22m 28s}  +23.16d {+23d 09' 22"}
  SUN_DIST:        109.78 [deg]   Sun_angle= -5.6 [hr] (East of Sun)
  MOON_POSTN:      167.68d {+11h 10m 44s}   +5.23d {+05d 13' 44"}
  MOON_DIST:        75.74 [deg]
  MOON_ILLUM:      46 [%]
  GAL_COORDS:      293.61, -9.61 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      222.11,-64.17 [deg] ecliptic lon,lat of the burst (or transient)
  COMMENTS:        SWIFT-BAT GRB Coordinates.  
  COMMENTS:        This is a rate trigger.  
  COMMENTS:        A point_source was found.  
  COMMENTS:        This does not match any source in the on-board catalog.  
  COMMENTS:        This does not match any source in the ground catalog.  
  COMMENTS:        This is a GRB.  
  COMMENTS:        This trigger occurred at longitude,latitude = 28.30,16.47 [deg].  
  

• red DSS finding chart ps-file
  
  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sat 11 Jun 16 21:44:17 UT
  NOTICE_TYPE:     Swift-BAT GRB Lightcurve
  TRIGGER_NUM:     690598,   Seg_Num: 0
  GRB_RA:          164.438d {+10h 57m 45s} (J2000),
                   164.579d {+10h 58m 19s} (current),
                   164.008d {+10h 56m 02s} (1950)
  GRB_DEC:         -70.395d {-70d 23' 40"} (J2000),
                   -70.483d {-70d 28' 58"} (current),
                   -70.127d {-70d 07' 36"} (1950)
  GRB_DATE:        17550 TJD;   163 DOY;   16/06/11
  GRB_TIME:        78034.41 SOD {21:40:34.41} UT
  TRIGGER_INDEX:   146
  GRB_PHI:         -151.76 [deg]
  GRB_THETA:        41.88 [deg]
  DELTA_TIME:      39.00 [sec]
  TRIGGER_DUR:     1.024 [sec] 
  SOLN_STATUS:     0x3
  RATE_SIGNIF:     11.31 [sigma]
  IMAGE_SIGNIF:    7.82 [sigma]
  LC_URL:          sw00690598000msb.lc
  SUN_POSTN:        80.62d {+05h 22m 28s}  +23.16d {+23d 09' 22"}
  SUN_DIST:        109.78 [deg]   Sun_angle= -5.6 [hr] (East of Sun)
  MOON_POSTN:      167.71d {+11h 10m 50s}   +5.22d {+05d 13' 12"}
  MOON_DIST:        75.73 [deg]
  MOON_ILLUM:      46 [%]
  GAL_COORDS:      293.61, -9.61 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      222.11,-64.17 [deg] ecliptic lon,lat of the burst (or transient)
  COMMENTS:        SWIFT-BAT GRB Lightcurve.  
  COMMENTS:           
  COMMENTS:        The next comments were copied from the BAT_POS Notice:  
  COMMENTS:        This is a rate trigger.  
  COMMENTS:        A point_source was found.  
  COMMENTS:        This does not match any source in the on-board catalog.  
  COMMENTS:        This does not match any source in the ground catalog.  
  COMMENTS:        This is a GRB.  
  COMMENTS:        This trigger occurred at longitude,latitude = 28.30,16.47 [deg].  
  

  
• GCN Circular #19522
  D. Malesani (DARK/NBI), S. D. Barthelmy (GSFC), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team:
  At 21:40:34 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 160611A (trigger=690598). Swift did not slew due to an observing constraint. The BAT on-board calculated location is RA, Dec 164.438, -70.395, which is

     RA(J2000)  =  10h 57m 45s
     Dec(J2000) = -70d 23' 40"
  

  with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows multiple peaks with a duration of about 30 sec. The peak count rate was ~2000 counts/sec (15-350 keV), at ~4 sec after the trigger.
  Due to an observing constraint, Swift will not slew until T0+43.3 minutes. There will be no XRT or UVOT data until this time.
  Burst Advocate for this burst is D. Malesani (malesani AT dark-cosmology.dk). 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 NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sat 11 Jun 16 22:25:22 UT
  NOTICE_TYPE:     Swift-XRT Nack-Position
  TRIGGER_NUM:     690598,   Seg_Num: 0
  POINT_RA:        164.364d {+10h 57m 27s} (J2000)
  POINT_DEC:       -70.385d {-70d 23' 04"} (J2000)
  IMG_START_DATE:  17550 TJD;   163 DOY;   16/06/11
  IMG_START_TIME:  80716.51 SOD {22:25:16.51} UT,   2682.1 [sec] since BAT Trigger Time
  COUNTS:          1    Min_needed= 20
  STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
  PH2_ITER:        0    Max_iter_allowed= 4
  ERROR_CODE:      1
  COMMENTS:        SWIFT-XRT Nack Position.  
  COMMENTS:        No source found in the image.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sat 11 Jun 16 22:31:13 UT
  NOTICE_TYPE:     Swift-UVOT Source List
  TRIGGER_NUM:     690598,   Seg_Num: 0
  POINT_RA:        164.360d {+10h 57m 26s} (J2000)
  POINT_DEC:       -70.386d {-70d 23' 08"} (J2000)
  POINT_ROLL:      283.949d
  IMG_START_DATE:  17550 TJD;   163 DOY;   16/06/11
  IMG_START_TIME:  80721.35 SOD {22:25:21.35} UT,   2686.9 [sec] since BAT Trigger Time
  FILTER:          10, White
  BKG_MEAN:        7.905
  N_STARS:         190
  X_OFFSET:        291 [pixels]
  Y_OFFSET:        643 [pixels]
  X_MAX:           1250 [pixels]
  Y_MAX:           1602 [pixels]
  DET_THRESH:      24
  PHOTO_THRESH:    15
  SL_URL:          sw00690598000msufc2686.fits
  SUN_POSTN:        80.65d {+05h 22m 36s}  +23.16d {+23d 09' 30"}
  SUN_DIST:        109.74 [deg]   Sun_angle= -5.6 [hr] (East of Sun)
  MOON_POSTN:      168.09d {+11h 12m 22s}   +5.10d {+05d 05' 54"}
  MOON_DIST:        75.61 [deg]
  MOON_ILLUM:      46 [%]
  GAL_COORDS:      293.58, -9.61 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      222.06,-64.19 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Source List.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sat 11 Jun 16 22:31:41 UT
  NOTICE_TYPE:     Swift-UVOT Processed Source List
  TRIGGER_NUM:     690598,   Seg_Num: 0
  POINT_RA:        164.360d {+10h 57m 26s} (J2000)
  POINT_DEC:       -70.386d {-70d 23' 08"} (J2000)
  POINT_ROLL:      283.949d
  IMG_START_DATE:  17550 TJD;   163 DOY;   16/06/11
  IMG_START_TIME:  80721.35 SOD {22:25:21.35} UT,   2686.9 [sec] since BAT Trigger Time
  FILTER:          10, White
  BKG_MEAN:        7.905
  N_STARS:         190
  X_OFFSET:        291 [pixels]
  Y_OFFSET:        643 [pixels]
  X_MAX:           1250 [pixels]
  Y_MAX:           1602 [pixels]
  DET_THRESH:      24
  PHOTO_THRESH:    15
  SL_URL:          sw00690598000msufc2686.fits
  SUN_POSTN:        80.65d {+05h 22m 36s}  +23.16d {+23d 09' 30"}
  SUN_DIST:        109.74 [deg]   Sun_angle= -5.6 [hr] (East of Sun)
  MOON_POSTN:      168.09d {+11h 12m 23s}   +5.10d {+05d 05' 50"}
  MOON_DIST:        75.61 [deg]
  MOON_ILLUM:      46 [%]
  GAL_COORDS:      293.58, -9.61 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      222.06,-64.19 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Processed Source List.  
  COMMENTS:        All 4 attachments are included.  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sat 11 Jun 16 22:33:01 UT
  NOTICE_TYPE:     Swift-UVOT Image
  TRIGGER_NUM:     690598,   Seg_Num: 0
  POINT_RA:        164.360d {+10h 57m 26s} (J2000)
  POINT_DEC:       -70.386d {-70d 23' 08"} (J2000)
  ROLL:            283.949d
  IMG_START_DATE:  17550 TJD;   163 DOY;   16/06/11
  IMG_START_TIME:  80721.35 SOD {22:25:21.35} UT,   2686.9 [sec] since BAT Trigger Time
  FILTER:          10, White
  EXPOSURE_ID:     487376737
  X_OFFSET:        610 [pixels]
  Y_OFFSET:        962 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       770
  Y_GRB_POS:       1122
  BINNING_INDEX:   1
  IM_URL:          sw00690598000msuni2703.fits
  SUN_POSTN:        80.65d {+05h 22m 37s}  +23.16d {+23d 09' 30"}
  SUN_DIST:        109.74 [deg]   Sun_angle= -5.6 [hr] (East of Sun)
  MOON_POSTN:      168.10d {+11h 12m 25s}   +5.09d {+05d 05' 37"}
  MOON_DIST:        75.61 [deg]
  MOON_ILLUM:      46 [%]
  GAL_COORDS:      293.58, -9.61 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      222.06,-64.19 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Image.  
  COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
  COMMENTS:        The image has 2x2 binning (compression).  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sat 11 Jun 16 22:33:19 UT
  NOTICE_TYPE:     Swift-UVOT Processed Image
  TRIGGER_NUM:     690598,   Seg_Num: 0
  POINT_RA:        164.360d {+10h 57m 26s} (J2000)
  POINT_DEC:       -70.386d {-70d 23' 08"} (J2000)
  ROLL:            283.949d
  IMG_START_DATE:  17550 TJD;   163 DOY;   16/06/11
  IMG_START_TIME:  80721.35 SOD {22:25:21.35} UT,   2686.9 [sec] since BAT Trigger Time
  FILTER:          10, White
  EXPOSURE_ID:     487376737
  X_OFFSET:        610 [pixels]
  Y_OFFSET:        962 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       770
  Y_GRB_POS:       1122
  BINNING_INDEX:   1
  IM_URL:          sw00690598000msuni2703.fits
  SUN_POSTN:        80.65d {+05h 22m 37s}  +23.16d {+23d 09' 30"}
  SUN_DIST:        109.74 [deg]   Sun_angle= -5.6 [hr] (East of Sun)
  MOON_POSTN:      168.11d {+11h 12m 26s}   +5.09d {+05d 05' 34"}
  MOON_DIST:        75.61 [deg]
  MOON_ILLUM:      46 [%]
  GAL_COORDS:      293.58, -9.61 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      222.06,-64.19 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Processed Image.  
  COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
  COMMENTS:        The image has 2x2 binning (compression).  
  COMMENTS:        All 4 attachments are included.  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sat 11 Jun 16 22:36:11 UT
  NOTICE_TYPE:     Swift-XRT Position
  TRIGGER_NUM:     690598,   Seg_Num: 0
  GRB_RA:          164.4226d {+10h 57m 41.42s} (J2000),
                   164.5644d {+10h 58m 15.46s} (current),
                   163.9932d {+10h 55m 58.37s} (1950)
  GRB_DEC:         -70.3930d {-70d 23' 34.8"} (J2000),
                   -70.4812d {-70d 28' 52.3"} (current),
                   -70.1251d {-70d 07' 30.3"} (1950)
  GRB_ERROR:       3.6 [arcsec radius, statistical plus systematic, 90% containment]
  GRB_INTEN:       1.00e-10 [erg/cm2/sec]
  GRB_SIGNIF:      10.00 [sigma]
  IMG_START_DATE:  17550 TJD;   163 DOY;   16/06/11
  IMG_START_TIME:  80829.00 SOD {22:27:09.00} UT,   2794.6 [sec] since BAT Trigger Time
  TAM[0-3]:        100.00 100.00 100.00 100.00
  AMPLIFIER:       1
  WAVEFORM:        31
  SUN_POSTN:        80.65d {+05h 22m 37s}  +23.16d {+23d 09' 30"}
  SUN_DIST:        109.76 [deg]   Sun_angle= -5.6 [hr] (East of Sun)
  MOON_POSTN:      168.13d {+11h 12m 31s}   +5.09d {+05d 05' 08"}
  MOON_DIST:        75.60 [deg]
  MOON_ILLUM:      46 [%]
  GAL_COORDS:      293.61, -9.61 [deg] galactic lon,lat of the burst
  ECL_COORDS:      222.10,-64.17 [deg] ecliptic lon,lat of the burst
  COMMENTS:        SWIFT-XRT Coordinates.  
  COMMENTS:        This Notice was ground-generated -- not flight-generated.  
  COMMENTS:        TAM values, flux and significance fields are not valid.  
  COMMENTS:        This position was automatically generated on the ground using  
  COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
  COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
  COMMENTS:        The probability that this is a serendipitous source in the  
  COMMENTS:        SPER window is 1.1% < P(seren) < 2.8%.  
  

• GCN Circular #19523
  J.P. Osborne (U. Leicester), D.N. Burrows (PSU), J.A. Kennea (PSU), G. Tagliaferri (INAF-OAB), S. Campana (INAF-OAB) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team:
  The XRT began observing the field of GRB 160611A at 22:25:16.5 UT, 2682.1 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 164.42342, -70.39301 which is equivalent to:

     RA(J2000)  = 10h 57m 41.62s
     Dec(J2000) = -70d 23' 34.8"
  

  with an uncertainty of 3.6 arcseconds (radius, 90% containment). This location is 19 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 (1.70 x 10^21 cm^-2, Willingale et al. 2013), with an excess column of 7.6 (+2.39/-2.15) x 10^21 cm^-2 (90% confidence).
• GCN Circular #19524
  J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
  Using 4788 s of XRT Photon Counting mode data and 10 UVOT images for GRB 160611A, 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 = 164.42229, -70.39243 which is equivalent to:

  RA (J2000): 10h 57m 41.35s
  Dec (J2000): -70d 23' 32.7"
  

  with an uncertainty of 1.5 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 Circular #19525
  V. Lipunov, E. Gorbovskoy, N.Tyurina, V.Kornilov, P.Balanutsa, A.Kuznetsov, D.Kuvshinov, Lomonosov Moscow State University, Sternberg Astronomical Institute
  D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory
  K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University
  A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Senik Kislovodsk Solar Station of the Pulkovo Observatory
  V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk
  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)
  R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias
  MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in SAAO was pointed to the GRB160611.9 24 sec after notice time and 54 sec after trigger time at 2016-06-11 21:41:28 UT. On our first (10s exposure) set we found 1 optical transient within SWIFT error-box (ra=10 57 45 dec=-70 23 41 r=0.050000) brighter then 15.

   T-Tmid      Date      Time       Expt.        Ra                Dec        Mag
  ---------|---------------------|-------|-----------------|-----------------|----
  +---
        59   2016-06-11 21:41:28      10   (10h 57m 57.87s , -70d 24m 47.1s)  14.67
  

  The 5-sigma upper limit has been about 15mag The message may be cited.
• GCN Circular #19526
  V. Lipunov (MASTER, LMSU)
  The OT wich published in GCN 19525 is the result of the false identification. I am sorry for my mistake.
  The message may be cited.
• GCN Circular #19527
  T.G.R. Roegiers (PSU), L.M. McCauley (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), B. Mingo (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), J.A. Kennea (PSU) and D. Malesani report on behalf of the Swift-XRT team:
  We have analysed 7.9 ks of XRT data for GRB 160611A (Malesani et al. GCN Circ. 19522), from 2.7 ks to 44.8 ks after the BAT trigger. The data comprise 50 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN Circ. 19524).
  The light curve can be modelled with a series of power-law decays. The initial decay index is alpha=1.54 (+0.48, -0.21). At T+5128 s the decay flattens to an alpha of -0.7 (+1.3, -0.8) before breaking again at T+7161 s to a final decay with index alpha=1.28 (+0.10, -0.09).
  A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.01 (+0.12, -0.11). The best-fitting absorption column is 5.0 (+0.7, -0.6) x 10^21 cm^-2, in excess of the Galactic value of 1.7 x 10^21 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 (6.6 x 10^-11) erg cm^-2 count^-1.
  A summary of the PC-mode spectrum is thus:

  Total column:	     5.0 (+0.7, -0.6) x 10^21 cm^-2
  Galactic foreground: 1.7 x 10^21 cm^-2
  Excess significance: 8.5 sigma
  Photon index:	     2.01 (+0.12, -0.11)
  

  If the light curve continues to decay with a power-law decay index of 1.28, the count rate at T+24 hours will be 0.021 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.4 x 10^-13 (1.4 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/00690598.
  This circular is an official product of the Swift-XRT team.
• GCN Circular #19529
  T. Sakamoto (AGU), S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), D. Malesani (DARK/NBI), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (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 160611A (trigger #690598) (Malesani, et al., GCN Circ. 19522). The BAT ground-calculated position is RA, Dec = 164.417, -70.396 deg which is

      RA(J2000)  =  10h 57m 40.0s
      Dec(J2000) = -70d 23' 45.8"
  

  with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment). The partial coding was 45%.
  The mask-weighted light curve shows a single episode with several overlapping pulses. The emission starts at T-15 sec, peaks at T+3 sec and ends at T+20 sec. T90 (15-350 keV) is 34.1 +- 5.6 sec (estimated error including systematics). A pre-planned spacecraft slew moved the source out of the field of view at about T+165 sec.
  The time-averaged spectrum from T-31.38 to T+10.37 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.67 +- 0.12. The fluence in the 15-150 keV band is 1.7 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+2.84 sec in the 15-150 keV band is 2.0 +- 0.3 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/690598/BA/
• GCN Circular #19530
  M. De Pasquale (UCL-MSSL) and D. Malesani (DARK/NBI) report on behalf of the Swift/UVOT team:
  The Swift/UVOT began settled observations of the field of GRB 160611A 2687 s after the BAT trigger (Malesani et al., GCN Circ. 19522).
  Very close to the XRT error circle (Osborne et al. GCN Circ. 19523), two sources are detected in the UVOT images. These sources are also detected in the Digitized Sky Survey (DSS) and are listed in the USNO catalog. Their light would blend with any new source at the XRT position, making the analysis more delicate.
  None of the two sources shows any significant flux decrease in the white filter between the first two white exposures (mid-time: 3071 s after the trigger) and the last three white exposures (mid-time: 10030 s after the trigger). Similarly, we find no significant decrease of the flux of the two sources in the u filter between the first u filter exposure (mid-time: 2946 s) and the last one (mid-time: 8560 s). We conclude that no optical afterglow consistent with the XRT position is detected in the UVOT exposures.
  Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) are:

  Filter         T_start(s)   T_stop(s)      Exp(s)         Mag
  
  white             2687         3456          344         >19.6
  white             9578        10478          880         >19.8
  v                 3668         3867          197         >18.1
  b                 3051         9573         1082         >18.9
  u                 2846         8660          393         >19.6
  w1                4078         5167          191         >19.7
  m2                3873         4072          197         >19.4
  w2                3463        10905          611         >20.6
  

  The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.22 in the direction of the burst (Schlegel et al. 1998).