Gamma-ray Burst 160313A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN/BACODINE POSITION NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 13 Mar 16 02:39:04 UT
  NOTICE_TYPE:     Swift-BAT GRB Position
  TRIGGER_NUM:     678929,   Seg_Num: 0
  GRB_RA:          183.788d {+12h 15m 09s} (J2000),
                   183.986d {+12h 15m 57s} (current),
                   183.174d {+12h 12m 42s} (1950)
  GRB_DEC:         +57.293d {+57d 17' 34"} (J2000),
                   +57.203d {+57d 12' 10"} (current),
                   +57.571d {+57d 34' 14"} (1950)
  GRB_ERROR:       3.00 [arcmin radius, statistical only]
  GRB_INTEN:       85670 [cnts]    Image_Peak=1043 [image_cnts]
  TRIGGER_DUR:     26.880 [sec] 
  TRIGGER_INDEX:   480     E_range: 25-100 keV
  BKG_INTEN:       192798 [cnts]
  BKG_TIME:        9328.02 SOD {02:35:28.02} UT
  BKG_DUR:         64 [sec]
  GRB_DATE:        17460 TJD;    73 DOY;   16/03/13
  GRB_TIME:        9435.80 SOD {02:37:15.80} UT
  GRB_PHI:         -103.03 [deg]
  GRB_THETA:        17.97 [deg]
  SOLN_STATUS:     0x3
  RATE_SIGNIF:     9.89 [sigma]
  IMAGE_SIGNIF:    8.71 [sigma]
  MERIT_PARAMS:     +1  +0  +0  +5  +2  -1  +0  +0 +57  +0 
  SUN_POSTN:       353.53d {+23h 34m 07s}   -2.80d {-02d 47' 45"}
  SUN_DIST:        124.96 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
  MOON_POSTN:       47.67d {+03h 10m 41s}  +13.24d {+13d 14' 39"}
  MOON_DIST:       100.88 [deg]
  MOON_ILLUM:      22 [%]
  GAL_COORDS:      132.50, 59.16 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      150.75, 51.83 [deg] ecliptic lon,lat of the burst (or transient)
  COMMENTS:        SWIFT-BAT GRB Coordinates.  
  COMMENTS:        This Notice was delayed by more than 60 sec past the end of the trigger integration interval;  
  COMMENTS:        probably due to it occurring during a Malindi downlink session.  
  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 = 11.29,19.87 [deg].  
  

• red DSS finding chart ps-file
  
  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 13 Mar 16 02:45:42 UT
  NOTICE_TYPE:     Swift-UVOT Image
  TRIGGER_NUM:     678929,   Seg_Num: 0
  POINT_RA:        183.776d {+12h 15m 06s} (J2000)
  POINT_DEC:       +57.268d {+57d 16' 06"} (J2000)
  ROLL:            12.493d
  IMG_START_DATE:  17460 TJD;    73 DOY;   16/03/13
  IMG_START_TIME:  9634.46 SOD {02:40:34.46} UT,   198.7 [sec] since BAT Trigger Time
  FILTER:          10, White
  EXPOSURE_ID:     479529650
  X_OFFSET:        953 [pixels]
  Y_OFFSET:        801 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1113
  Y_GRB_POS:       961
  BINNING_INDEX:   1
  IM_URL:          sw00678929000msuni0214.fits
  SUN_POSTN:       353.53d {+23h 34m 08s}   -2.79d {-02d 47' 38"}
  SUN_DIST:        124.99 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
  MOON_POSTN:       47.74d {+03h 10m 57s}  +13.26d {+13d 15' 31"}
  MOON_DIST:       100.85 [deg]
  MOON_ILLUM:      22 [%]
  GAL_COORDS:      132.52, 59.18 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      150.77, 51.81 [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:     Sun 13 Mar 16 02:53:31 UT
  NOTICE_TYPE:     Swift-UVOT Source List
  TRIGGER_NUM:     678929,   Seg_Num: 0
  POINT_RA:        183.775d {+12h 15m 06s} (J2000)
  POINT_DEC:       +57.270d {+57d 16' 11"} (J2000)
  POINT_ROLL:      12.492d
  IMG_START_DATE:  17460 TJD;    73 DOY;   16/03/13
  IMG_START_TIME:  10290.28 SOD {02:51:30.28} UT,   854.5 [sec] since BAT Trigger Time
  FILTER:          10, White
  BKG_MEAN:        1.879
  N_STARS:         57
  X_OFFSET:        394 [pixels]
  Y_OFFSET:        242 [pixels]
  X_MAX:           1833 [pixels]
  Y_MAX:           1681 [pixels]
  DET_THRESH:      11
  PHOTO_THRESH:    6
  SL_URL:          sw00678929000msufc0854.fits
  SUN_POSTN:       353.54d {+23h 34m 09s}   -2.79d {-02d 47' 31"}
  SUN_DIST:        124.98 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
  MOON_POSTN:       47.82d {+03h 11m 16s}  +13.28d {+13d 16' 33"}
  MOON_DIST:       100.81 [deg]
  MOON_ILLUM:      22 [%]
  GAL_COORDS:      132.52, 59.18 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      150.76, 51.81 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Source List.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 13 Mar 16 02:47:08 UT
  NOTICE_TYPE:     Swift-UVOT Processed Source List
  TRIGGER_NUM:     678929,   Seg_Num: 0
  POINT_RA:        183.776d {+12h 15m 06s} (J2000)
  POINT_DEC:       +57.268d {+57d 16' 06"} (J2000)
  POINT_ROLL:      12.493d
  IMG_START_DATE:  17460 TJD;    73 DOY;   16/03/13
  IMG_START_TIME:  9634.46 SOD {02:40:34.46} UT,   198.7 [sec] since BAT Trigger Time
  FILTER:          10, White
  BKG_MEAN:        3.185
  N_STARS:         37
  X_OFFSET:        634 [pixels]
  Y_OFFSET:        482 [pixels]
  X_MAX:           1593 [pixels]
  Y_MAX:           1441 [pixels]
  DET_THRESH:      15
  PHOTO_THRESH:    8
  SL_URL:          sw00678929000msufc0198.fits
  SUN_POSTN:       353.54d {+23h 34m 08s}   -2.79d {-02d 47' 37"}
  SUN_DIST:        124.99 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
  MOON_POSTN:       47.75d {+03h 11m 00s}  +13.26d {+13d 15' 42"}
  MOON_DIST:       100.84 [deg]
  MOON_ILLUM:      22 [%]
  GAL_COORDS:      132.52, 59.18 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      150.77, 51.81 [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:     Sun 13 Mar 16 02:46:52 UT
  NOTICE_TYPE:     Swift-UVOT Processed Image
  TRIGGER_NUM:     678929,   Seg_Num: 0
  POINT_RA:        183.776d {+12h 15m 06s} (J2000)
  POINT_DEC:       +57.268d {+57d 16' 06"} (J2000)
  ROLL:            12.493d
  IMG_START_DATE:  17460 TJD;    73 DOY;   16/03/13
  IMG_START_TIME:  9634.46 SOD {02:40:34.46} UT,   198.7 [sec] since BAT Trigger Time
  FILTER:          10, White
  EXPOSURE_ID:     479529650
  X_OFFSET:        953 [pixels]
  Y_OFFSET:        801 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1113
  Y_GRB_POS:       961
  BINNING_INDEX:   1
  IM_URL:          sw00678929000msuni0214.fits
  SUN_POSTN:       353.54d {+23h 34m 08s}   -2.79d {-02d 47' 37"}
  SUN_DIST:        124.99 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
  MOON_POSTN:       47.75d {+03h 11m 00s}  +13.26d {+13d 15' 40"}
  MOON_DIST:       100.85 [deg]
  MOON_ILLUM:      22 [%]
  GAL_COORDS:      132.52, 59.18 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      150.77, 51.81 [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:        If you have elected to receive attachments:  
  COMMENTS:        The uvot_catalog_image.fits.gz file does not exist; skipping the attachment.  
  

  
• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 13 Mar 16 02:54:45 UT
  NOTICE_TYPE:     Swift-UVOT Image
  TRIGGER_NUM:     678929,   Seg_Num: 0
  POINT_RA:        183.775d {+12h 15m 06s} (J2000)
  POINT_DEC:       +57.270d {+57d 16' 11"} (J2000)
  ROLL:            12.492d
  IMG_START_DATE:  17460 TJD;    73 DOY;   16/03/13
  IMG_START_TIME:  10290.28 SOD {02:51:30.28} UT,   854.5 [sec] since BAT Trigger Time
  FILTER:          10, White
  EXPOSURE_ID:     479530306
  X_OFFSET:        953 [pixels]
  Y_OFFSET:        801 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       1113
  Y_GRB_POS:       961
  BINNING_INDEX:   1
  IM_URL:          sw00678929000msuni0870.fits
  SUN_POSTN:       353.54d {+23h 34m 10s}   -2.79d {-02d 47' 29"}
  SUN_DIST:        124.98 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
  MOON_POSTN:       47.83d {+03h 11m 19s}  +13.28d {+13d 16' 42"}
  MOON_DIST:       100.80 [deg]
  MOON_ILLUM:      22 [%]
  GAL_COORDS:      132.52, 59.18 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      150.76, 51.81 [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:     Sun 13 Mar 16 02:47:17 UT
  NOTICE_TYPE:     Swift-XRT Position
  TRIGGER_NUM:     678929,   Seg_Num: 0
  GRB_RA:          183.7963d {+12h 15m 11.11s} (J2000),
                   183.9943d {+12h 15m 58.63s} (current),
                   183.1823d {+12h 12m 43.75s} (1950)
  GRB_DEC:         +57.2839d {+57d 17' 02.0"} (J2000),
                   +57.1939d {+57d 11' 38.1"} (current),
                   +57.5618d {+57d 33' 42.4"} (1950)
  GRB_ERROR:       2.3 [arcsec radius, statistical plus systematic, 90% containment]
  GRB_INTEN:       1.00e-10 [erg/cm2/sec]
  GRB_SIGNIF:      10.00 [sigma]
  IMG_START_DATE:  17460 TJD;    73 DOY;   16/03/13
  IMG_START_TIME:  9633.00 SOD {02:40:33.00} UT,   197.2 [sec] since BAT Trigger Time
  TAM[0-3]:        100.00 100.00 100.00 100.00
  AMPLIFIER:       1
  WAVEFORM:        31
  SUN_POSTN:       353.54d {+23h 34m 08s}   -2.79d {-02d 47' 37"}
  SUN_DIST:        124.97 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
  MOON_POSTN:       47.75d {+03h 11m 01s}  +13.26d {+13d 15' 44"}
  MOON_DIST:       100.84 [deg]
  MOON_ILLUM:      22 [%]
  GAL_COORDS:      132.49, 59.17 [deg] galactic lon,lat of the burst
  ECL_COORDS:      150.76, 51.83 [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:        This position was enhanced using UVOT field astrometry.  
  COMMENTS:        The probability that this is a serendipitous source in the  
  COMMENTS:        SPER window is 0.58% < P(seren) < 1.1%.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 13 Mar 16 02:44:40 UT
  NOTICE_TYPE:     Swift-UVOT Source List
  TRIGGER_NUM:     678929,   Seg_Num: 0
  POINT_RA:        183.776d {+12h 15m 06s} (J2000)
  POINT_DEC:       +57.268d {+57d 16' 06"} (J2000)
  POINT_ROLL:      12.493d
  IMG_START_DATE:  17460 TJD;    73 DOY;   16/03/13
  IMG_START_TIME:  9634.46 SOD {02:40:34.46} UT,   198.7 [sec] since BAT Trigger Time
  FILTER:          10, White
  BKG_MEAN:        3.185
  N_STARS:         37
  X_OFFSET:        634 [pixels]
  Y_OFFSET:        482 [pixels]
  X_MAX:           1593 [pixels]
  Y_MAX:           1441 [pixels]
  DET_THRESH:      15
  PHOTO_THRESH:    8
  SL_URL:          sw00678929000msufc0198.fits
  SUN_POSTN:       353.53d {+23h 34m 08s}   -2.79d {-02d 47' 39"}
  SUN_DIST:        124.99 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
  MOON_POSTN:       47.73d {+03h 10m 54s}  +13.26d {+13d 15' 23"}
  MOON_DIST:       100.86 [deg]
  MOON_ILLUM:      22 [%]
  GAL_COORDS:      132.52, 59.18 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      150.77, 51.81 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Source List.  
  

• GCN NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 13 Mar 16 02:40:07 UT
  NOTICE_TYPE:     Swift-XRT Nack-Position
  TRIGGER_NUM:     678929,   Seg_Num: 0
  POINT_RA:        183.776d {+12h 15m 06s} (J2000)
  POINT_DEC:       +57.273d {+57d 16' 21"} (J2000)
  IMG_START_DATE:  17460 TJD;    73 DOY;   16/03/13
  IMG_START_TIME:  9588.31 SOD {02:39:48.31} UT,   152.5 [sec] since BAT Trigger Time
  COUNTS:          8    Min_needed= 20
  STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
  PH2_ITER:        2    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:     Sun 13 Mar 16 02:53:45 UT
  NOTICE_TYPE:     Swift-UVOT Processed Source List
  TRIGGER_NUM:     678929,   Seg_Num: 0
  POINT_RA:        183.775d {+12h 15m 06s} (J2000)
  POINT_DEC:       +57.270d {+57d 16' 11"} (J2000)
  POINT_ROLL:      12.492d
  IMG_START_DATE:  17460 TJD;    73 DOY;   16/03/13
  IMG_START_TIME:  10290.28 SOD {02:51:30.28} UT,   854.5 [sec] since BAT Trigger Time
  FILTER:          10, White
  BKG_MEAN:        1.879
  N_STARS:         57
  X_OFFSET:        394 [pixels]
  Y_OFFSET:        242 [pixels]
  X_MAX:           1833 [pixels]
  Y_MAX:           1681 [pixels]
  DET_THRESH:      11
  PHOTO_THRESH:    6
  SL_URL:          sw00678929000msufc0854.fits
  SUN_POSTN:       353.54d {+23h 34m 09s}   -2.79d {-02d 47' 30"}
  SUN_DIST:        124.98 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
  MOON_POSTN:       47.82d {+03h 11m 16s}  +13.28d {+13d 16' 35"}
  MOON_DIST:       100.80 [deg]
  MOON_ILLUM:      22 [%]
  GAL_COORDS:      132.52, 59.18 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      150.76, 51.81 [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:     Sun 13 Mar 16 02:42:35 UT
  NOTICE_TYPE:     Swift-BAT GRB Lightcurve
  TRIGGER_NUM:     678929,   Seg_Num: 0
  GRB_RA:          183.788d {+12h 15m 09s} (J2000),
                   183.986d {+12h 15m 57s} (current),
                   183.174d {+12h 12m 42s} (1950)
  GRB_DEC:         +57.293d {+57d 17' 34"} (J2000),
                   +57.203d {+57d 12' 10"} (current),
                   +57.571d {+57d 34' 14"} (1950)
  GRB_DATE:        17460 TJD;    73 DOY;   16/03/13
  GRB_TIME:        9435.80 SOD {02:37:15.80} UT
  TRIGGER_INDEX:   480
  GRB_PHI:         -103.03 [deg]
  GRB_THETA:        17.97 [deg]
  DELTA_TIME:      -56.00 [sec]
  TRIGGER_DUR:     26.880 [sec] 
  SOLN_STATUS:     0x3
  RATE_SIGNIF:     9.89 [sigma]
  IMAGE_SIGNIF:    8.71 [sigma]
  LC_URL:          sw00678929000msb.lc
  SUN_POSTN:       353.53d {+23h 34m 08s}   -2.80d {-02d 47' 41"}
  SUN_DIST:        124.96 [deg]   Sun_angle= 11.3 [hr] (West of Sun)
  MOON_POSTN:       47.71d {+03h 10m 49s}  +13.25d {+13d 15' 07"}
  MOON_DIST:       100.86 [deg]
  MOON_ILLUM:      22 [%]
  GAL_COORDS:      132.50, 59.16 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      150.75, 51.83 [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 = 11.29,19.87 [deg].  
  

  
• GCN NOTICE
  

   
  TITLE:           GCN/SWIFT NOTICE 
  NOTICE_DATE:     Sun 13 Mar 16 02:54:54 UT 
  NOTICE_TYPE:     Swift-UVOT Processed Image 
  TRIGGER_NUM:     678929,   Seg_Num: 0 
  POINT_RA:        183.775d {+12h 15m 06s} (J2000) 
  POINT_DEC:       +57.270d {+57d 16' 11"} (J2000) 
  ROLL:            12.492d 
  IMG_START_DATE:  17460 TJD;    73 DOY;   16/03/13 
  IMG_START_TIME:  10290.28 SOD {02:51:30.28} UT,   854.5 [sec] since BAT Trigger Time 
  FILTER:          10, White 
  EXPOSURE_ID:     479530306 
  X_OFFSET:        953 [pixels] 
  Y_OFFSET:        801 [pixels] 
  WIDTH:           160 [pixels] 
  HEIGHT:          160 [pixels] 
  X_GRB_POS:       1113 
  Y_GRB_POS:       961 
  BINNING_INDEX:   1 
  IM_URL:          sw00678929000msuni0870.fits 
  SUN_POSTN:       353.54d {+23h 34m 10s}   -2.79d {-02d 47' 29"} 
  SUN_DIST:        124.98 [deg]   Sun_angle= 11.3 [hr] (West of Sun) 
  MOON_POSTN:       47.83d {+03h 11m 19s}  +13.28d {+13d 16' 44"} 
  MOON_DIST:       100.80 [deg] 
  MOON_ILLUM:      22 [%] 
  GAL_COORDS:      132.52, 59.18 [deg] galactic lon,lat of the pointing direction 
  ECL_COORDS:      150.76, 51.81 [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 Circular #19171
  A. D'Ai (INAF-IASFPA), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), A. Y. Lien (GSFC/UMBC), A. Maselli (INAF-IASFPA), L. M. McCauley (PSU), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU), M. H. Siegel (PSU) and T. N. Ukwatta (LANL) report on behalf of the Swift Team:
  At 02:37:15 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 160313A (trigger=678929). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 183.788, +57.293 which is

     RA(J2000)  =  12h 15m 09s
     Dec(J2000) = +57d 17' 34"
  

  with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows several peaks with a total duration of about 40 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~30 sec after the trigger.
  The XRT began observing the field at 02:39:48.3 UT, 152.5 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 183.7969, 57.2840 which is equivalent to:

     RA(J2000)  = 12h 15m 11.24s
     Dec(J2000) = +57d 17' 02.3"
  

  with an uncertainty of 2.2 arcseconds (radius, 90% containment). This location is 36 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. No spectrum from the promptly downlinked event data is yet available to determine the column density.
  UVOT took a finding chart exposure of 150 seconds with the White filter starting 198 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 0.01.
  Burst Advocate for this burst is A. D'Ai (antonino.dai AT ifc.inaf.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.)
• GCN Circular #19172
  A. Moskvitin (SAO RAS, Russia) report on behalf of the larger team.
  The field of GRB 160313A (D'Ai et al., GCNC #19171) was observed with the SAO RAS Zeiss-1000 telescope. The observations started during the morning twilight, since 10 minutes after the trigger.
  In combined image of 4 x 60 seconds in the Rc band we did not detect any object within the XRT error circle down to the limiting magnitude R_lim = 18.2. This estimation based on the nearby USNO-B1 stars.
• GCN Circular #19173
  Antonino Cucchiara (GSFC/STScI), Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jos=E9 A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes=FAs Gonz=E1lez (UNAM), Carlos Rom=E1n-Z=FA=F1iga (UNAM), Neil Gehrels (GSFC), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report:
  We observed the field of GRB 160313A (D'Ai, et al., GCN 19171) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astron=F3mico Nacional on Sierra San Pedro M=E1rtir from 2016/03 13.14 to 2016/03 13.22 UTC (0.63 to 2.67 hours after the BAT trigger), obtaining a total of 1.42 hours exposure in the r and i bands and 0.52 hours exposure in the Z, Y, J, and H bands.
  For a source within the Swift-XRT error circle, in comparison with the SDSS DR9 and 2MASS catalogs, we obtain the following upper limits (3-sigma):

   
    r     > 23.49 
    i     > 23.21 
    Z     > 22.08 
    Y     > 21.48 
    J     > 20.11 
    H     > 20.60 
  

  These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. Further observations are planned.
  We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro M=E1rtir.
• GCN Circular #19174
  M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team.
  Using 722 s of XRT Photon Counting mode data and 2 UVOT images for GRB 160313A, 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 = 183.79649, +57.28347 which is equivalent to:

  RA (J2000): 12h 15m 11.16s
  Dec (J2000): +57d 17' 00.5"
  

  with an uncertainty of 1.9 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 #19175
  Klotz A., Turpin D., Atteia J.L. (CNRS-OMP-IRAP), Boer, M., Laugier, R. (CNRS-ARTEMIS), Gendre B. (UVI - Etelman Obs.) report:
  We imaged the field of GRB 160313A detected by SWIFT (trigger 678929) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France.
  The observations started 122s after the GRB trigger (20s after the notice). The elevation of the field decreased from 64 degrees above horizon and weather conditions were good but images are slightly defocused.
  The first image is trailed with a duration of 60.0s (see the description in Klotz et al., 2006, A&A 451, L39). We do not detect any OT in the XRT error box published by Goad et al. (GCNC 19174). Next images are recorded with diurnal tracking.

    
  t1(s) t2(s)  Rmag_lim  Site  
    122   182   15.8      TAROT Calern  
    198   228   16.9      TAROT Calern  
    239   269   16.8      TAROT Calern  
    280   393   18.7      TAROT Calern  
    405  1226   18.7      TAROT Calern  
   1237  3172   19.2      TAROT Calern  
  

  Magnitudes were estimated with nearby USNO-B1 stars and are not corrected for galactic dust extinction.
• GCN Circular #19176
  J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), V. D'Elia (ASDC), A. Maselli (INAF-IASFPA), L.M. McCauley (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), C. Pagani (U. Leicester) and A. D'Ai report on behalf of the Swift-XRT team:
  We have analysed 7.1 ks of XRT data for GRB 160313A (D'Ai et al. GCN Circ. 19171), from 138 s to 22.9 ks after the BAT trigger. The data comprise 39 s in Windowed Timing (WT) mode (the first 7 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. 19174).
  The light curve can be modelled with a power-law decay with a decay index of alpha=3.23 (+0.18, -0.16).
  A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.9 (+/-0.4). The best-fitting absorption column is 1.7 (+1.4, -1.1) x 10^21 cm^-2, in excess of the Galactic value of 1.3 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 3.8 x 10^-11 (4.8 x 10^-11) erg cm^-2 count^-1.
  A summary of the PC-mode spectrum is thus:

  Total column:	     1.7 (+1.4, -1.1) x 10^21 cm^-2
  Galactic foreground: 1.3 x 10^20 cm^-2
  Excess significance: 2.3 sigma
  Photon index:	     1.9 (+/-0.4)
  

  If the light curve continues to decay with a power-law decay index of 3.23, the count rate at T+24 hours will be 1.1 x 10^-8 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.0 x 10^-19 (5.0 x 10^-19) erg cm^-2 s^-1.
  The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00678929.
  This circular is an official product of the Swift-XRT team.
• GCN Circular #19177
  D. Kopac (U. Ljubljana), C. Guidorzi (U. Ferrara), S. Kobayashi (LJMU), A. Gomboc (U. Nova Gorica), C.G. Mundell (U. Bath), on behalf of a large collaboration report:
  The 2-m Liverpool Telescope began observing Swift GRB 160313A (D'Ai et al., GCN 19171) on March 13, 02:40:45 UT (3.5 minutes after the burst trigger). Inside the XRT error circle (Goad et al., GCN 19174) we find no source down to r'> 21.0 mag in a 6x10s exposure (at 36.5 min, mid time), as calibrated against nearby SDSS stars, in agreement with previous reports (Moskvitin et al. GCN 19172; Cucchiara et al. GCN 19173; Klotz et al. GCN 19175).
• GCN Circular #19178
  E. Gorbovskoy, V. Lipunov, V.Kornilov, D.Kuvshinov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.V.Chazov Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow 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
  K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University
  V.Krushinski, I.Zalozhnih, A. Popov Ural Federal University, Kourovka
  D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory
  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 Kislovodsk was pointed to the GRB160313A 21 sec after notice time and 129 sec after trigger time at 2016-03-13 02:39:24 UT in two polarizations. On our first (30s exposure) and following coadd images we haven`t found optical transient within SWIFT error-box (D'Ai et al GCN 19171). The observations took during the morning twilight. We have a 5 good images before they become overexposed.
  The 5-sigma upper limit has been about 16.5 on first single (30s exposure) image and 17.2 on coadd (300 s exposure) image.
  The message may be cited.
• GCN Circular #19179
  Kugel F., Rinner C. (Observatoire Chante-Perdrix, Dauban), and Klotz A. (CNRS-OMP-IRAP) report:
  F. Kugel imaged the field of GRB 160313A detected by SWIFT (trigger 678929) with the D=40cm F/D=3 telescope located at the Observatoire Chante-Perdrix, Dauban, France (IAU station A77). The CCD camera is ARTEMIS ATIK-460ex, no optical filter is used.
  The observations started 17.4 min after the GRB trigger.
  The first image is 60 second exposure. No optical transcient is detected in the XRT error box published by Goad et al. (GCNC 19174). Next images are co-added:

   
  t1(min) t2(min)  Rmag_lim 
  17.4    18.4     19.5 
  17.4    42.4     20.0 
  

  Magnitudes were estimated with nearby USNO-B1 stars and are not corrected for galactic dust extinction.
• GCN Circular #19181
  S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), A. D'Ai (INAF-IASFPA), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), 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-691 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 160313A (trigger #678929) (A. D'Ai et al., GCN Circ. 19171). The BAT ground-calculated position is RA, Dec = 183.821, 57.278 deg which is

   
    RA(J2000)  =  12h 15m 17.0s 
    Dec(J2000) = +57d 16' 40.1" 
  

  with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 80%.
  The mask-weighted light curve shows a complex structure with several overlapping pulses. The structure starts at ~ T-5 s and ends at ~ T+45 s. T90 (15-350 keV) is 42.6 +- 6.4 sec (estimated error including systematics).
  The time-averaged spectrum from T-5.6 to T+44.7 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.36 +- 0.23. The fluence in the 15-150 keV band is 5.8 +- 0.8 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+24.79 sec in the 15-150 keV band is 0.4 +- 0.1 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/678929/BA/
• GCN Circular #19194
  L. M. McCauley (PSU) and A. D'Ai (INAF-IASFPA) reports on behalf of the Swift/UVOT team:
  The Swift/UVOT began settled observations of the field of GRB 160313A 198 s after the BAT trigger (D'Ai et al., GCN Circ. 19171). No optical afterglow consistent with the XRT position (Goad et al. GCN Circ. 19174) 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) exposure and subsequent exposures are:

  Filter         T_start(s)   T_stop(s)      Exp(s)         Mag
  
  white_FC              198         920         418        >20.77
  white                 198        5756         664        >21.01
  v                     355        6167         451        >19.78
  b                     454        5552         254        >20.24
  u                     430        6588         260        >19.44
  uvw1                  405        6577         451        >19.93
  uvm2                 4737        6372         393        >19.17
  uvw2                 4328        5962         393        >19.99
  

  The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.01 in the direction of the burst (Schlegel et al. 1998).
• GCN Circular #19201
  E. Mazaeva (IKI), A. Volnova (IKI), E. Klunko (ISTP), I. Korobtsev (ISTP), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
  We observed the field of the GRB 160313A (D'Ai et al., GCN 19171) with AZT-33IK telescope of Sayan observatory (Mondy) starting on March, 13 (UT) 16:39:40. We do not detect any source within enhanced Swift-XRT position (Goad et al., GCN 19174). Preliminary photometry of the combined image is following

  Date        UT start   t-T0    Filter  Exp.    UpperLimit (3 sigma)
                         (mid, days)      (s)
  
  2016-03-13  16:39:40  0.60586  R       30*120  23.6
  

  Photometry is based on nearby SDSS-DR9 stars, Lupton transformations into R.
  The nearest source to the enhanced XRT position is 5.5 arcsec East, in coordinates (J2000) 12:15:11.86 +57:17:00.0 with uncertainty of 0.5 arcsec in both coordinates. The source magnitude is R=23.3+/-0.2. The source is not presented in SDSS-DR9 but barely visible in SDSS r-image.
• GCN Circular #19450
  K. P. Mooley, T. D. Staley, R. P. Fender (Oxford), G. E. Anderson (Curtin), C. Rumsey, D. Titterington, S. Carey, J. Hickish, Y. C. Perrott, N. Razavi-Ghods, P. Scott (Cambridge), K. Grainge, A. Scaife (Manchester)
  The AMI Large Array robotically triggered on the Swift alert for GRB 160313A (D'Ai et al., GCN 19171) as part of the 4pisky program, and subsequent follow up observations were obtained up to 10 days post-burst. Our observations at 15 GHz on 2016 Mar 13.15, Mar 13.97, Mar 16.00, Mar 20.11, and Mar 23.02 (UT) do not reveal any radio source at the XRT location (Goad et al., GCN 19174), with 3sigma upper limits of 130 uJy, 60 uJy, 100 uJy, 170 uJy, and 70 uJy respectively.
  We thank the AMI staff for scheduling these observations. The AMI-GRB database is a log of all GRB follow up observations with the AMI, and is available at http://4pisky.org/ami-grb/.