Gamma-ray Burst 170419A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 19 Apr 17 13:27:03 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     748898,   Seg_Num: 0
GRB_RA:           79.866d {+05h 19m 28s} (J2000),
                  80.050d {+05h 20m 12s} (current),
                  79.333d {+05h 17m 20s} (1950)
GRB_DEC:         -21.420d {-21d 25' 12"} (J2000),
                 -21.404d {-21d 24' 12"} (current),
                 -21.471d {-21d 28' 13"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       4337 [cnts]    Image_Peak=184 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   137     E_range: 15-50 keV
BKG_INTEN:       28112 [cnts]
BKG_TIME:        48381.06 SOD {13:26:21.06} UT
BKG_DUR:         8 [sec]
GRB_DATE:        17862 TJD;   109 DOY;   17/04/19
GRB_TIME:        48400.20 SOD {13:26:40.20} UT
GRB_PHI:           5.00 [deg]
GRB_THETA:        40.07 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     11.53 [sigma]
IMAGE_SIGNIF:    7.66 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +1  -2  +0  +0 -48  +0 
SUN_POSTN:        27.61d {+01h 50m 26s}  +11.36d {+11d 21' 33"}
SUN_DIST:         61.02 [deg]   Sun_angle= -3.5 [hr] (East of Sun)
MOON_POSTN:      302.79d {+20h 11m 10s}  -17.41d {-17d 24' 31"}
MOON_DIST:       122.91 [deg]
MOON_ILLUM:      49 [%]
GAL_COORDS:      223.46,-29.35 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       76.75,-44.39 [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 = 352.38,-12.91 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 19 Apr 17 13:28:33 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     748898,   Seg_Num: 0
POINT_RA:         79.850d {+05h 19m 24s} (J2000)
POINT_DEC:       -21.408d {-21d 24' 27"} (J2000)
IMG_START_DATE:  17862 TJD;   109 DOY;   17/04/19
IMG_START_TIME:  48501.37 SOD {13:28:21.37} UT,   101.2 [sec] since BAT Trigger Time
COUNTS:          14    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        1    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:     Wed 19 Apr 17 13:30:18 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     748898,   Seg_Num: 0
GRB_RA:           79.866d {+05h 19m 28s} (J2000),
                  80.050d {+05h 20m 12s} (current),
                  79.333d {+05h 17m 20s} (1950)
GRB_DEC:         -21.420d {-21d 25' 12"} (J2000),
                 -21.404d {-21d 24' 12"} (current),
                 -21.471d {-21d 28' 13"} (1950)
GRB_DATE:        17862 TJD;   109 DOY;   17/04/19
GRB_TIME:        48400.20 SOD {13:26:40.20} UT
TRIGGER_INDEX:   137
GRB_PHI:           5.00 [deg]
GRB_THETA:        40.07 [deg]
DELTA_TIME:      6.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     11.53 [sigma]
IMAGE_SIGNIF:    7.66 [sigma]
LC_URL:          sw00748898000msb.lc
SUN_POSTN:        27.61d {+01h 50m 27s}  +11.36d {+11d 21' 36"}
SUN_DIST:         61.02 [deg]   Sun_angle= -3.5 [hr] (East of Sun)
MOON_POSTN:      302.82d {+20h 11m 17s}  -17.40d {-17d 24' 17"}
MOON_DIST:       122.89 [deg]
MOON_ILLUM:      49 [%]
GAL_COORDS:      223.46,-29.35 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       76.75,-44.39 [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 = 352.38,-12.91 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 19 Apr 17 13:39:24 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     748898,   Seg_Num: 0
GRB_RA:           79.8557d {+05h 19m 25.36s} (J2000),
                  80.0401d {+05h 20m 09.63s} (current),
                  79.3228d {+05h 17m 17.46s} (1950)
GRB_DEC:         -21.4244d {-21d 25' 27.8"} (J2000),
                 -21.4076d {-21d 24' 27.3"} (current),
                 -21.4747d {-21d 28' 28.9"} (1950)
GRB_ERROR:       4.7 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  17862 TJD;   109 DOY;   17/04/19
IMG_START_TIME:  48965.00 SOD {13:36:05.00} UT,   564.8 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        27.62d {+01h 50m 28s}  +11.36d {+11d 21' 43"}
SUN_DIST:         61.01 [deg]   Sun_angle= -3.5 [hr] (East of Sun)
MOON_POSTN:      302.90d {+20h 11m 36s}  -17.39d {-17d 23' 38"}
MOON_DIST:       122.83 [deg]
MOON_ILLUM:      49 [%]
GAL_COORDS:      223.46,-29.36 [deg] galactic lon,lat of the burst
ECL_COORDS:       76.73,-44.40 [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 0.58% < P(seren) < 1.1%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 19 Apr 17 13:42:08 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     748898,   Seg_Num: 0
POINT_RA:         79.849d {+05h 19m 24s} (J2000)
POINT_DEC:       -21.409d {-21d 24' 32"} (J2000)
POINT_ROLL:      297.472d
IMG_START_DATE:  17862 TJD;   109 DOY;   17/04/19
IMG_START_TIME:  48991.84 SOD {13:36:31.84} UT,   591.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.108
N_STARS:         47
X_OFFSET:        347 [pixels]
Y_OFFSET:        604 [pixels]
X_MAX:           1306 [pixels]
Y_MAX:           1563 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00748898000msufc0591.fits
SUN_POSTN:        27.62d {+01h 50m 28s}  +11.36d {+11d 21' 46"}
SUN_DIST:         60.99 [deg]   Sun_angle= -3.5 [hr] (East of Sun)
MOON_POSTN:      302.92d {+20h 11m 42s}  -17.39d {-17d 23' 26"}
MOON_DIST:       122.82 [deg]
MOON_ILLUM:      49 [%]
GAL_COORDS:      223.44,-29.36 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.73,-44.38 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 19 Apr 17 13:42:54 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     748898,   Seg_Num: 0
POINT_RA:         79.849d {+05h 19m 24s} (J2000)
POINT_DEC:       -21.409d {-21d 24' 32"} (J2000)
POINT_ROLL:      297.472d
IMG_START_DATE:  17862 TJD;   109 DOY;   17/04/19
IMG_START_TIME:  48991.84 SOD {13:36:31.84} UT,   591.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.108
N_STARS:         47
X_OFFSET:        347 [pixels]
Y_OFFSET:        604 [pixels]
X_MAX:           1306 [pixels]
Y_MAX:           1563 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00748898000msufc0591.fits
SUN_POSTN:        27.62d {+01h 50m 29s}  +11.36d {+11d 21' 46"}
SUN_DIST:         60.99 [deg]   Sun_angle= -3.5 [hr] (East of Sun)
MOON_POSTN:      302.93d {+20h 11m 44s}  -17.39d {-17d 23' 23"}
MOON_DIST:       122.81 [deg]
MOON_ILLUM:      49 [%]
GAL_COORDS:      223.44,-29.36 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.73,-44.38 [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:     Wed 19 Apr 17 13:42:48 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     748898,   Seg_Num: 0
GRB_RA:           79.8549d {+05h 19m 25.17s} (J2000),
                  80.0393d {+05h 20m 09.44s} (current),
                  79.3220d {+05h 17m 17.27s} (1950)
GRB_DEC:         -21.4242d {-21d 25' 27.1"} (J2000),
                 -21.4074d {-21d 24' 26.6"} (current),
                 -21.4745d {-21d 28' 28.2"} (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:  17862 TJD;   109 DOY;   17/04/19
IMG_START_TIME:  48965.00 SOD {13:36:05.00} UT,   564.8 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        27.62d {+01h 50m 28s}  +11.36d {+11d 21' 46"}
SUN_DIST:         61.00 [deg]   Sun_angle= -3.5 [hr] (East of Sun)
MOON_POSTN:      302.93d {+20h 11m 43s}  -17.39d {-17d 23' 23"}
MOON_DIST:       122.81 [deg]
MOON_ILLUM:      49 [%]
GAL_COORDS:      223.46,-29.36 [deg] galactic lon,lat of the burst
ECL_COORDS:       76.73,-44.40 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        This is an Update Notice -- the RA,Dec values herein supersede the previous XRT_POS Notice.  
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:     Wed 19 Apr 17 13:43:40 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     748898,   Seg_Num: 0
POINT_RA:         79.849d {+05h 19m 24s} (J2000)
POINT_DEC:       -21.409d {-21d 24' 32"} (J2000)
ROLL:            297.472d
IMG_START_DATE:  17862 TJD;   109 DOY;   17/04/19
IMG_START_TIME:  48991.84 SOD {13:36:31.84} UT,   591.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     514301810
X_OFFSET:        666 [pixels]
Y_OFFSET:        923 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       826
Y_GRB_POS:       1083
BINNING_INDEX:   1
IM_URL:          sw00748898000msuni0610.fits
SUN_POSTN:        27.62d {+01h 50m 29s}  +11.36d {+11d 21' 47"}
SUN_DIST:         60.99 [deg]   Sun_angle= -3.5 [hr] (East of Sun)
MOON_POSTN:      302.94d {+20h 11m 45s}  -17.39d {-17d 23' 19"}
MOON_DIST:       122.81 [deg]
MOON_ILLUM:      49 [%]
GAL_COORDS:      223.44,-29.36 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.73,-44.38 [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:     Wed 19 Apr 17 13:44:03 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     748898,   Seg_Num: 0
POINT_RA:         79.849d {+05h 19m 24s} (J2000)
POINT_DEC:       -21.409d {-21d 24' 32"} (J2000)
ROLL:            297.472d
IMG_START_DATE:  17862 TJD;   109 DOY;   17/04/19
IMG_START_TIME:  48991.84 SOD {13:36:31.84} UT,   591.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     514301810
X_OFFSET:        666 [pixels]
Y_OFFSET:        923 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       826
Y_GRB_POS:       1083
BINNING_INDEX:   1
IM_URL:          sw00748898000msuni0610.fits
SUN_POSTN:        27.62d {+01h 50m 29s}  +11.36d {+11d 21' 47"}
SUN_DIST:         60.99 [deg]   Sun_angle= -3.5 [hr] (East of Sun)
MOON_POSTN:      302.94d {+20h 11m 46s}  -17.39d {-17d 23' 18"}
MOON_DIST:       122.81 [deg]
MOON_ILLUM:      49 [%]
GAL_COORDS:      223.44,-29.36 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.73,-44.38 [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:     Wed 19 Apr 17 13:47:41 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     748898,   Seg_Num: 0
POINT_RA:         79.849d {+05h 19m 24s} (J2000)
POINT_DEC:       -21.409d {-21d 24' 31"} (J2000)
POINT_ROLL:      297.472d
IMG_START_DATE:  17862 TJD;   109 DOY;   17/04/19
IMG_START_TIME:  49270.71 SOD {13:41:10.71} UT,   870.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.183
N_STARS:         120
X_OFFSET:        107 [pixels]
Y_OFFSET:        364 [pixels]
X_MAX:           1546 [pixels]
Y_MAX:           1803 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00748898000msufc0870.fits
SUN_POSTN:        27.62d {+01h 50m 29s}  +11.36d {+11d 21' 51"}
SUN_DIST:         60.99 [deg]   Sun_angle= -3.5 [hr] (East of Sun)
MOON_POSTN:      302.97d {+20h 11m 54s}  -17.38d {-17d 23' 02"}
MOON_DIST:       122.79 [deg]
MOON_ILLUM:      49 [%]
GAL_COORDS:      223.44,-29.36 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.73,-44.38 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 19 Apr 17 13:48:10 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     748898,   Seg_Num: 0
POINT_RA:         79.849d {+05h 19m 24s} (J2000)
POINT_DEC:       -21.409d {-21d 24' 31"} (J2000)
POINT_ROLL:      297.472d
IMG_START_DATE:  17862 TJD;   109 DOY;   17/04/19
IMG_START_TIME:  49270.71 SOD {13:41:10.71} UT,   870.5 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.183
N_STARS:         120
X_OFFSET:        107 [pixels]
Y_OFFSET:        364 [pixels]
X_MAX:           1546 [pixels]
Y_MAX:           1803 [pixels]
DET_THRESH:      12
PHOTO_THRESH:    6
SL_URL:          sw00748898000msufc0870.fits
SUN_POSTN:        27.62d {+01h 50m 29s}  +11.36d {+11d 21' 51"}
SUN_DIST:         60.99 [deg]   Sun_angle= -3.5 [hr] (East of Sun)
MOON_POSTN:      302.98d {+20h 11m 55s}  -17.38d {-17d 23' 00"}
MOON_DIST:       122.78 [deg]
MOON_ILLUM:      49 [%]
GAL_COORDS:      223.44,-29.36 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.73,-44.38 [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:     Wed 19 Apr 17 13:49:04 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     748898,   Seg_Num: 0
POINT_RA:         79.849d {+05h 19m 24s} (J2000)
POINT_DEC:       -21.409d {-21d 24' 31"} (J2000)
ROLL:            297.472d
IMG_START_DATE:  17862 TJD;   109 DOY;   17/04/19
IMG_START_TIME:  49270.71 SOD {13:41:10.71} UT,   870.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     514302089
X_OFFSET:        666 [pixels]
Y_OFFSET:        923 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       826
Y_GRB_POS:       1083
BINNING_INDEX:   1
IM_URL:          sw00748898000msuni0889.fits
SUN_POSTN:        27.62d {+01h 50m 29s}  +11.36d {+11d 21' 52"}
SUN_DIST:         60.99 [deg]   Sun_angle= -3.5 [hr] (East of Sun)
MOON_POSTN:      302.99d {+20h 11m 57s}  -17.38d {-17d 22' 56"}
MOON_DIST:       122.78 [deg]
MOON_ILLUM:      49 [%]
GAL_COORDS:      223.44,-29.36 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.73,-44.38 [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:     Wed 19 Apr 17 13:49:24 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     748898,   Seg_Num: 0
POINT_RA:         79.849d {+05h 19m 24s} (J2000)
POINT_DEC:       -21.409d {-21d 24' 31"} (J2000)
ROLL:            297.472d
IMG_START_DATE:  17862 TJD;   109 DOY;   17/04/19
IMG_START_TIME:  49270.71 SOD {13:41:10.71} UT,   870.5 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     514302089
X_OFFSET:        666 [pixels]
Y_OFFSET:        923 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       826
Y_GRB_POS:       1083
BINNING_INDEX:   1
IM_URL:          sw00748898000msuni0889.fits
SUN_POSTN:        27.62d {+01h 50m 30s}  +11.36d {+11d 21' 52"}
SUN_DIST:         60.99 [deg]   Sun_angle= -3.5 [hr] (East of Sun)
MOON_POSTN:      302.99d {+20h 11m 57s}  -17.38d {-17d 22' 55"}
MOON_DIST:       122.78 [deg]
MOON_ILLUM:      49 [%]
GAL_COORDS:      223.44,-29.36 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       76.73,-44.38 [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 #21013
B. Sbarufatti (INAF-OAB/PSU), S. D. Barthelmy (GSFC), A. A. Breeveld (UCL-MSSL), D. N. Burrows (PSU), A. Cholden-Brown (PSU), C. Gronwall (PSU), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), M. H. Siegel (PSU) and T. N. Ukwatta (LANL) report on behalf of the Swift Team:
At 13:26:40 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 170419A (trigger=748898). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 79.866, -21.420 which is
```
   RA(J2000)  =  05h 19m 28s
   Dec(J2000) = -21d 25' 12"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single peak with a duration of about 5 sec. The peak count rate was ~1700 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT settled on the field at 13:28:21.4 UT, 101.2 seconds after the BAT trigger. XRT data were delayed for about 8 minutes until Swift exited the SAA. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 79.8549, -21.4240 which is equivalent to:
```
   RA(J2000)  = 05h 19m 25.18s
   Dec(J2000) = -21d 25' 26.4"
```
with an uncertainty of 2.5 arcseconds (radius, 90% containment). This location is 39 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. We cannot determine whether the source is fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 3.50 x 10^20 cm^-2 (Willingale et al. 2013).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 591 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 0.05.
Burst Advocate for this burst is B. Sbarufatti (boris.sbarufatti AT brera.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 #21015
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team.
Using 2234 s of XRT Photon Counting mode data and 3 UVOT images for GRB 170419A, 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 = 79.85468, -21.42386 which is equivalent to:
```
RA (J2000): 05h 19m 25.12s
Dec (J2000): -21d 25' 25.9"
```
with an uncertainty of 1.6 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 #21018
M. Stamatikos (OSU), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), N. Gehrels (GSFC), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), B. Sbarufatti (INAF-OAB/PSU), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-190 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 170419A (trigger #748898) (Sbarufatti et al., GCN Circ. 21013). The BAT ground-calculated position is RA, Dec = 79.854, -21.433 deg which is
```
  RA(J2000)  =  05h 19m 25.1s
  Dec(J2000) = -21d 25' 58.0"
```
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 53%.
The mask-weighted light curve shows a single-pulse structure that starts and peaks at ~T0. The main emission ends at ~T+3 s, with a tail that lasts till ~T+9 s. T90 (15-350 keV) is 8.18 +- 2.00 sec (estimated error including systematics).
The time-averaged spectrum from T-0.39 to T+8.92 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.06 +- 0.26. The fluence in the 15-150 keV band is 3.1 +- 0.5 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.47 sec in the 15-150 keV band is 1.5 +- 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/748898/BA/
GCN Circular #21021
V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), S. J. LaPorte (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), B. Mingo (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester) and report on behalf of the Swift-XRT team: report on behalf of the Swift-XRT team:
We have analysed 6.2 ks of XRT data for GRB 170419A, from 550 s to 59.3 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode.
The light curve can be modelled with a power-law decay with a decay index of alpha=1.02 (+0.14, -0.12).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.7 (+/-0.3). The best-fitting absorption column is 1.6 (+1.2, -1.0) x 10^21 cm^-2, in excess of the Galactic value of 3.5 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 4.1 x 10^-11 (5.0 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     1.6 (+1.2, -1.0) x 10^21 cm^-2
Galactic foreground: 3.5 x 10^20 cm^-2
Excess significance: 2.1 sigma
Photon index:	     1.7 (+/-0.3)
```
If the light curve continues to decay with a power-law decay index of 1.02, the count rate at T+24 hours will be 1.5 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 6.3 x 10^-14 (7.7 x 10^-14) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00748898.
This circular is an official product of the Swift-XRT team.
GCN Circular #21023
A. Klotz, D. Turpin (IRAP-CNRS-OMP), D. Macpherson (UWA/ICRAR), D. Coward (UWA), M. Boer, (UNS-CNRS-OCA), Gendre B. (UVI - Etelman Obs.), A. Williams (PO-UWA), R. Martin (PO-UWA) report:
We imaged the field of GRB 170419A detected by SWIFT (trigger 748898) with the Zadko robotic telescope (D=100cm) located at the observatory - Gingin, Australia.
The observations started 22.3h after the GRB trigger. The elevation of the field decreased from 49 degrees above horizon and weather conditions were good.
We co-added a series of exposures but we did not find any optical transcient in the XRT error box provided by Goad et al. (GCNC 21015):
t0+22.3h to t0+22.9h : Rlim = 21.0
Magnitudes were estimated with the nearby NOMAD1 stars and are not corrected for galactic dust extinction.
GCN Circular #21031
A. Cucchiara, D. Morris (U. of Virgin Islands), C. Guidorzi (U. Ferrara), and B. Gendre (U. of Virgin Islands) report on behalf of a larger collaboration:
"On April 19.71 UT (T_0 +3.6h) we began observing the field of GRB 170419A (Sbarufatti et al. GCN #21013) using the Las Cumbres Observatory Global Network 1m Sutherland facility.
We obtained a series of observations in R and I bands for a total of 5 minutes on target in each filter. We identified no optical counterpart within the Enhanced Swift-XRT position (Goad et al. GCN #21015) at the following 3-sigma limits:
```
R > 20.9 mag
I > 20.8 mag
```
These values are calibrated against nearby USNO-B1 sources and are not corrected for Galactic Extinction."
GCN Circular #21035
M. H. Siegel (PSU) and B. Sbarufatti (INAF-OAB/PSU) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 170419A 592 s after the BAT trigger (Sbarufatti et al., GCN Circ. 21013). No optical afterglow consistent with the XRT position (Goad et al. GCN Circ. 21015) 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           592          742          147         >21.1
white              592        13376         1194         >22.0
v                  748        19148          594         >19.6
b                  846         7551          313         >20.4
u                  822        23245         1108         >21.0
w1                 797         7141          313         >20.0
m2                 773         6935          274         >19.9
w2                1027        17141          672         >20.7
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.05 in the direction of the burst (Schlegel et al. 1998).

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Jochen Greiner, last update: 25-Apr-2017 [Disclaimer]