Gamma-ray Burst 170205A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 05 Feb 17 12:39:24 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     736843,   Seg_Num: 0
GRB_RA:          262.151d {+17h 28m 36s} (J2000),
                 262.370d {+17h 29m 29s} (current),
                 261.510d {+17h 26m 02s} (1950)
GRB_DEC:          -0.053d {-00d 03' 08"} (J2000),
                  -0.065d {-00d 03' 55"} (current),
                  -0.013d {-00d 00' 46"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       790 [cnts]    Image_Peak=87 [image_cnts]
TRIGGER_DUR:     0.064 [sec] 
TRIGGER_INDEX:   10418     E_range: 25-100 keV
BKG_INTEN:       15313 [cnts]
BKG_TIME:        45533.43 SOD {12:38:53.43} UT
BKG_DUR:         8 [sec]
GRB_DATE:        17789 TJD;    36 DOY;   17/02/05
GRB_TIME:        45549.75 SOD {12:39:09.75} UT
GRB_PHI:         146.68 [deg]
GRB_THETA:        16.46 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     10.86 [sigma]
IMAGE_SIGNIF:    8.30 [sigma]
MERIT_PARAMS:     +1  +0  +0  -4  +2  -1  +0  +0 -51  +0 
SUN_POSTN:       319.36d {+21h 17m 26s}  -15.77d {-15d 46' 01"}
SUN_DIST:         58.36 [deg]   Sun_angle= 3.8 [hr] (West of Sun)
MOON_POSTN:       63.84d {+04h 15m 21s}  +15.92d {+15d 55' 04"}
MOON_DIST:       155.80 [deg]
MOON_ILLUM:      65 [%]
GAL_COORDS:       23.10, 18.32 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      261.46, 23.15 [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 = 338.99,-10.74 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 05 Feb 17 12:40:49 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     736843,   Seg_Num: 0
GRB_RA:          262.1699d {+17h 28m 40.77s} (J2000),
                 262.3891d {+17h 29m 33.38s} (current),
                 261.5292d {+17h 26m 07.00s} (1950)
GRB_DEC:          -0.0634d {-00d 03' 48.2"} (J2000),
                  -0.0762d {-00d 04' 34.2"} (current),
                  -0.0239d {-00d 01' 26.1"} (1950)
GRB_ERROR:       4.8 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       7.05e-09 [erg/cm2/sec]
GRB_SIGNIF:      14.07 [sigma]
IMG_START_DATE:  17789 TJD;    36 DOY;   17/02/05
IMG_START_TIME:  45610.91 SOD {12:40:10.91} UT,   61.2 [sec] since BAT Trigger Time
TAM[0-3]:        327.67 237.22 261.62 243.40
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       319.36d {+21h 17m 26s}  -15.77d {-15d 46' 00"}
SUN_DIST:         58.34 [deg]   Sun_angle= 3.8 [hr] (West of Sun)
MOON_POSTN:       63.85d {+04h 15m 24s}  +15.92d {+15d 55' 13"}
MOON_DIST:       155.80 [deg]
MOON_ILLUM:      65 [%]
GAL_COORDS:       23.10, 18.30 [deg] galactic lon,lat of the burst
ECL_COORDS:      261.48, 23.14 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 1.32 arcmin from the BAT position.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 05 Feb 17 12:41:10 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     736843,   Seg_Num: 0
GRB_RA:          262.1699d {+17h 28m 40.7s} (J2000),
                 262.3891d {+17h 29m 33.3s} (current),
                 261.5292d {+17h 26m 07.0s} (1950)
GRB_DEC:          -0.0634d {-00d 03' 48.2"} (J2000),
                  -0.0762d {-00d 04' 34.2"} (current),
                  -0.0239d {-00d 01' 26.1"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       198 [cnts]
IMG_START_DATE:  17789 TJD;    36 DOY;   17/02/05
IMG_START_TIME:  45610.91 SOD {12:40:10.91} UT,   61.2 [sec] since BAT Trigger Time
CENTROID_X:      281.80,  raw= 282  [pixels]
CENTROID_Y:      295.42,  raw= 295  [pixels]
ROLL:            108.54 [deg]
GAIN:            2
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -7.02
GRB_POS_XRT_Z:   -57.98
IMAGE_URL:       sw00736843000msxps_rw.img
SUN_POSTN:       319.36d {+21h 17m 26s}  -15.77d {-15d 46' 00"}
SUN_DIST:         58.34 [deg]   Sun_angle= 3.8 [hr] (West of Sun)
MOON_POSTN:       63.85d {+04h 15m 25s}  +15.92d {+15d 55' 15"}
MOON_DIST:       155.80 [deg]
MOON_ILLUM:      65 [%]
GAL_COORDS:       23.10, 18.30 [deg] galactic lon,lat of the burst
ECL_COORDS:      261.48, 23.14 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 05 Feb 17 12:41:05 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     736843,   Seg_Num: 0
GRB_RA:          262.1699d {+17h 28m 40.7s} (J2000),
                 262.3891d {+17h 29m 33.3s} (current),
                 261.5292d {+17h 26m 07.0s} (1950)
GRB_DEC:          -0.0634d {-00d 03' 48.2"} (J2000),
                  -0.0762d {-00d 04' 34.2"} (current),
                  -0.0239d {-00d 01' 26.1"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       198 [cnts]
IMG_START_DATE:  17789 TJD;    36 DOY;   17/02/05
IMG_START_TIME:  45610.91 SOD {12:40:10.91} UT,   61.2 [sec] since BAT Trigger Time
CENTROID_X:      281.80,  raw= 282  [pixels]
CENTROID_Y:      295.42,  raw= 295  [pixels]
ROLL:            108.54 [deg]
GAIN:            2
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -7.02
GRB_POS_XRT_Z:   -57.98
IMAGE_URL:       sw00736843000msxps_rw.img
SUN_POSTN:       319.36d {+21h 17m 26s}  -15.77d {-15d 46' 00"}
SUN_DIST:         58.34 [deg]   Sun_angle= 3.8 [hr] (West of Sun)
MOON_POSTN:       63.85d {+04h 15m 25s}  +15.92d {+15d 55' 15"}
MOON_DIST:       155.80 [deg]
MOON_ILLUM:      65 [%]
GAL_COORDS:       23.10, 18.30 [deg] galactic lon,lat of the burst
ECL_COORDS:      261.48, 23.14 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 05 Feb 17 12:43:00 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     736843,   Seg_Num: 0
GRB_RA:          262.151d {+17h 28m 36s} (J2000),
                 262.370d {+17h 29m 29s} (current),
                 261.510d {+17h 26m 02s} (1950)
GRB_DEC:          -0.053d {-00d 03' 08"} (J2000),
                  -0.065d {-00d 03' 55"} (current),
                  -0.013d {-00d 00' 46"} (1950)
GRB_DATE:        17789 TJD;    36 DOY;   17/02/05
GRB_TIME:        45549.95 SOD {12:39:09.95} UT
TRIGGER_INDEX:   10418
GRB_PHI:         146.68 [deg]
GRB_THETA:        16.46 [deg]
DELTA_TIME:      -51.00 [sec]
TRIGGER_DUR:     0.064 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     10.86 [sigma]
IMAGE_SIGNIF:    8.30 [sigma]
LC_URL:          sw00736843000msb.lc
SUN_POSTN:       319.36d {+21h 17m 27s}  -15.77d {-15d 45' 58"}
SUN_DIST:         58.36 [deg]   Sun_angle= 3.8 [hr] (West of Sun)
MOON_POSTN:       63.87d {+04h 15m 29s}  +15.92d {+15d 55' 27"}
MOON_DIST:       155.82 [deg]
MOON_ILLUM:      65 [%]
GAL_COORDS:       23.10, 18.32 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      261.46, 23.15 [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 = 338.99,-10.74 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 05 Feb 17 12:52:30 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     736843,   Seg_Num: 0
POINT_RA:        262.156d {+17h 28m 37s} (J2000)
POINT_DEC:        -0.058d {-00d 03' 28"} (J2000)
POINT_ROLL:      108.537d
IMG_START_DATE:  17789 TJD;    36 DOY;   17/02/05
IMG_START_TIME:  45864.03 SOD {12:44:24.03} UT,   314.3 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        7.414
N_STARS:         90
X_OFFSET:        422 [pixels]
Y_OFFSET:        556 [pixels]
X_MAX:           1381 [pixels]
Y_MAX:           1515 [pixels]
DET_THRESH:      24
PHOTO_THRESH:    14
SL_URL:          sw00736843000msufc0314.fits
SUN_POSTN:       319.37d {+21h 17m 28s}  -15.76d {-15d 45' 51"}
SUN_DIST:         58.36 [deg]   Sun_angle= 3.8 [hr] (West of Sun)
MOON_POSTN:       63.97d {+04h 15m 52s}  +15.94d {+15d 56' 28"}
MOON_DIST:       155.88 [deg]
MOON_ILLUM:      66 [%]
GAL_COORDS:       23.10, 18.31 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      261.46, 23.15 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sun 05 Feb 17 12:52:58 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     736843,   Seg_Num: 0
POINT_RA:        262.156d {+17h 28m 37s} (J2000)
POINT_DEC:        -0.058d {-00d 03' 28"} (J2000)
POINT_ROLL:      108.537d
IMG_START_DATE:  17789 TJD;    36 DOY;   17/02/05
IMG_START_TIME:  45864.03 SOD {12:44:24.03} UT,   314.3 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        7.414
N_STARS:         90
X_OFFSET:        422 [pixels]
Y_OFFSET:        556 [pixels]
X_MAX:           1381 [pixels]
Y_MAX:           1515 [pixels]
DET_THRESH:      24
PHOTO_THRESH:    14
SL_URL:          sw00736843000msufc0314.fits
SUN_POSTN:       319.37d {+21h 17m 28s}  -15.76d {-15d 45' 51"}
SUN_DIST:         58.36 [deg]   Sun_angle= 3.8 [hr] (West of Sun)
MOON_POSTN:       63.97d {+04h 15m 53s}  +15.94d {+15d 56' 31"}
MOON_DIST:       155.88 [deg]
MOON_ILLUM:      66 [%]
GAL_COORDS:       23.10, 18.31 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      261.46, 23.15 [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 05 Feb 17 12:53:03 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     736843,   Seg_Num: 0
GRB_RA:          262.1696d {+17h 28m 40.70s} (J2000),
                 262.3888d {+17h 29m 33.30s} (current),
                 261.5289d {+17h 26m 06.92s} (1950)
GRB_DEC:          -0.0626d {-00d 03' 45.3"} (J2000),
                  -0.0754d {-00d 04' 31.3"} (current),
                  -0.0231d {-00d 01' 23.2"} (1950)
GRB_ERROR:       2.2 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  17789 TJD;    36 DOY;   17/02/05
IMG_START_TIME:  45821.00 SOD {12:43:41.00} UT,   271.2 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       319.37d {+21h 17m 28s}  -15.76d {-15d 45' 51"}
SUN_DIST:         58.35 [deg]   Sun_angle= 3.8 [hr] (West of Sun)
MOON_POSTN:       63.97d {+04h 15m 54s}  +15.94d {+15d 56' 31"}
MOON_DIST:       155.88 [deg]
MOON_ILLUM:      66 [%]
GAL_COORDS:       23.10, 18.30 [deg] galactic lon,lat of the burst
ECL_COORDS:      261.48, 23.15 [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:     Sun 05 Feb 17 12:54:08 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     736843,   Seg_Num: 0
POINT_RA:        262.156d {+17h 28m 37s} (J2000)
POINT_DEC:        -0.058d {-00d 03' 28"} (J2000)
ROLL:            108.537d
IMG_START_DATE:  17789 TJD;    36 DOY;   17/02/05
IMG_START_TIME:  45864.03 SOD {12:44:24.03} UT,   314.3 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     507991482
X_OFFSET:        741 [pixels]
Y_OFFSET:        875 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       901
Y_GRB_POS:       1035
BINNING_INDEX:   1
IM_URL:          sw00736843000msuni0333.fits
SUN_POSTN:       319.37d {+21h 17m 29s}  -15.76d {-15d 45' 50"}
SUN_DIST:         58.36 [deg]   Sun_angle= 3.8 [hr] (West of Sun)
MOON_POSTN:       63.98d {+04h 15m 56s}  +15.94d {+15d 56' 38"}
MOON_DIST:       155.89 [deg]
MOON_ILLUM:      66 [%]
GAL_COORDS:       23.10, 18.31 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      261.46, 23.15 [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 05 Feb 17 12:54:33 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     736843,   Seg_Num: 0
POINT_RA:        262.156d {+17h 28m 37s} (J2000)
POINT_DEC:        -0.058d {-00d 03' 28"} (J2000)
ROLL:            108.537d
IMG_START_DATE:  17789 TJD;    36 DOY;   17/02/05
IMG_START_TIME:  45864.03 SOD {12:44:24.03} UT,   314.3 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     507991482
X_OFFSET:        741 [pixels]
Y_OFFSET:        875 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       901
Y_GRB_POS:       1035
BINNING_INDEX:   1
IM_URL:          sw00736843000msuni0333.fits
SUN_POSTN:       319.37d {+21h 17m 29s}  -15.76d {-15d 45' 49"}
SUN_DIST:         58.36 [deg]   Sun_angle= 3.8 [hr] (West of Sun)
MOON_POSTN:       63.99d {+04h 15m 57s}  +15.94d {+15d 56' 41"}
MOON_DIST:       155.89 [deg]
MOON_ILLUM:      66 [%]
GAL_COORDS:       23.10, 18.31 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      261.46, 23.15 [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:     Sun 05 Feb 17 12:56:43 UT
NOTICE_TYPE:     Swift-UVOT Position
TRIGGER_NUM:     736843,   Seg_Num: 0
GRB_RA:          262.1695d {+17h 28m 40.68s} (J2000),
                 262.3887d {+17h 29m 33.28s} (current),
                 261.5288d {+17h 26m 06.90s} (1950)
GRB_DEC:          -0.0631d {-00d 03' 47.1"} (J2000),
                  -0.0759d {-00d 04' 33.1"} (current),
                  -0.0236d {-00d 01' 25.0"} (1950)
GRB_ERROR:       0.6 [arcsec radius, statistical only]
GRB_MAG:         17.62 +/- 0.14 [mag]
FILTER:          10, White
IMG_START_DATE:  17789 TJD;    36 DOY;   17/02/05
IMG_START_TIME:  45861.00 SOD {12:44:21.00} UT,   311.2 [sec] since BAT Trigger Time
SUN_POSTN:       319.37d {+21h 17m 29s}  -15.76d {-15d 45' 48"}
SUN_DIST:         58.35 [deg]   Sun_angle= 3.8 [hr] (West of Sun)
MOON_POSTN:       64.01d {+04h 16m 03s}  +15.95d {+15d 56' 55"}
MOON_DIST:       155.90 [deg]
MOON_ILLUM:      66 [%]
GAL_COORDS:       23.10, 18.30 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      261.48, 23.14 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT UVOT Position Notice.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The UVOT position is 1.8 arcsec from the XRT position.  
COMMENTS:        Result based on Genie data.  
COMMENTS:        Notice generated automatically.

GCN Circular #20603
E. Troja (NASA/GSFC/UMCP), D. N. Burrows (PSU), A. Cholden-Brown (PSU), H. A. Krimm (CRESST/NSF/USRA), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC) and K. L. Page (U Leicester) report on behalf of the Swift Team:
At 12:39:09 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 170205A (trigger=736843). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 262.151, -0.053 which is
```
   RA(J2000) = 17h 28m 36s
   Dec(J2000) = -00d 03' 08"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a double-peaked structure with a duration of about 25 sec. The peak count rate was ~5000 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 12:40:10.9 UT, 61.1 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source with an enhanced position: RA, Dec 262.1696, -0.0626 which is equivalent to:
```
   RA(J2000)  = 17h 28m 40.70s
   Dec(J2000) = -00d 03' 45.3"
```
with an uncertainty of 2.2 arcseconds (radius, 90% containment). This location is 75 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 (1.97 x 10^21 cm^-2, Willingale et al. 2013), with an excess column of 6.4 (+5.93/-4.46) x 10^21 cm^-2 (90% confidence).
The initial flux in the 2.5 s image was 7.05e-09 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 314 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 17:28:40.69 = 262.16953 DEC(J2000) = -00:03:47.3 = -0.06313 with a 90%-confidence error radius of about 0.62 arc sec. This position is 1.9 arc sec. from the center of the XRT error circle. The estimated magnitude is 17.62 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.35.
Burst Advocate for this burst is E. Troja (eleonora.troja AT nasa.gov). 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 #20605
C. Guidorzi (U. Ferrara), S. Kobayashi, I.A. Steele (LJMU), A. Gomboc (U. Nova Gorica), C.G. Mundell (U. Bath) on behalf of a large collaboration report:
We observed Swift GRB 170205A (Troja et al. GCN 20603) on February 05, from 14:40 UT (2.0 hours since the GRB) with the 2-m LCO FTN in Hawaii with SDSS r and i filters. We detect the optical afterglow at the Swift-UVOT position with the following values:
```
Mid Time      Exposure       Filter       Magnitude (AB)
(hours)           (s)
-------------------------------------------------------
2.0             2x120         SDSS-R        20.3 +- 0.1
2.1             2x120         SDSS-I        20.0 +- 0.1
-------------------------------------------------------
```
as calibrated against nearby SDSS sources.
GCN Circular #20609
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), Antonino Cucchiara (UVI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), 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 170205A (Troja, et al., GCN 20603) 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 2017/02 5.53 to 2017/02 5.58 UTC (2.3 minutes to 1.25 hours after the BAT trigger), obtaining a total of 0.61 hours exposure in the r and i bands and 0.29 hours exposure in the Z and Y bands.
In comparison with the USNO-B1 and 2MASS catalogs, we obtain the following detections for the optical afterglow (see, also, Guidorzi, et al., GCN 20605):
```
r =3D 18.31 +/- 0.01
i =3D 17.90 +/- 0.01
Z =3D 18.06 +/- 0.01
Y =3D 19.26 +/- 0.07
```
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. The source fades (from i~16 mag) as t^(-1.6) until ~15 minutes after the GRB, after which the fade flattens to t^(-1.1).
We thank the staff of the Observatorio Astron=F3mico Nacional in San Pedro M=E1rtir.
GCN Circular #20610
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team.
Using 2830 s of XRT Photon Counting mode data and 4 UVOT images for GRB 170205A, 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 = 262.16934, -0.06320 which is equivalent to:
```
RA (J2000): 17h 28m 40.64s
Dec (J2000): -00d 03' 47.5"
```
with an uncertainty of 1.4 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 #20611
V. D'Elia (ASDC), A. Cholden-Brown (PSU), S. J. LaPorte (PSU), J.A. Kennea (PSU), P.A. Evans (U. Leicester), S.L. Gibson (U. Leicester), J.P. Osborne (U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB) and E. Troja report on behalf of the Swift-XRT team:
We have analysed 10 ks of XRT data for GRB 170205A (Troja et al. GCN Circ. 20603), from 271 s to 34.9 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN Circ. 20610).
The light curve can be modelled with a power-law decay with a decay index of alpha=0.89 (+0.03, -0.04).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.87 (+0.14, -0.13). The best-fitting absorption column is 3.4 (+0.7, -0.6) x 10^21 cm^-2, in excess of the Galactic value of 2.0 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 4.1 x 10^-11 (5.7 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     3.4 (+0.7, -0.6) x 10^21 cm^-2
Galactic foreground: 2.0 x 10^21 cm^-2
Excess significance: 3.8 sigma
Photon index:	     1.87 (+0.14, -0.13)
```
If the light curve continues to decay with a power-law decay index of 0.89, 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 8.5 x 10^-13 (1.2 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/00736843.
This circular is an official product of the Swift-XRT team.
GCN Circular #20612
T. Kruehler (MPE Garching), D. Xu (NAOC,CAS), K. E. Heintz (Univ. Iceland & DARK/NBI) and G. Fedorets (NOT) report on behalf of the Nordic GRB collaboration:
We observed the field of GRB 170205A (Troja et al. GCN 20603) with the NOT equipped with ALFOSC. Photometry in the r and i-band started at 05:49 UTC on 2017-02-06, 17.2 hr after the GRB trigger, and was obtained under adverse atmospheric conditions (seeing around 2.5").
Calibrating our images against magnitudes of field stars from the SDSS catalog, we measure preliminary brightnesses of the optical afterglow (Troja et al. GCN 20603, Guidorzi et al. GCN 20605, Butler et al. GCN 20609) of
```
r = 22.2 +- 0.2 mag and
i = 22.0 +- 0.2 mag.
```
These magnitudes are not corrected for the expected foreground extinction corresponding to a reddening of E_B-V = 0.30 mag (Schlafly & Finkbeiner 2011).
GCN Circular #20613
H. A. Krimm (NSF/USRA), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), N. Gehrels (GSFC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), E. Troja (NASA/GSFC/UMCP), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-10 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 170205A (trigger #736843) (Troja, et al., GCN Circ. 20603). The BAT ground-calculated position is RA, Dec = 262.157, -0.058 deg which is
```
  RA(J2000)  =  17h 28m 37.8s
  Dec(J2000) = -00d 03' 30.4"
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 91%.
The mask-weighted light curve shows that the burst consisted of two peaks of roughly equal peak counts, the first from T-2 sec to T+12 sec and the second from T+12 sec to T+30 sec. T90 (15-350 keV) is 26.1 +- 3.2 sec (estimated error including systematics). It is possible that the burst is longer than this since there was no data before T-10 seconds, following the re-enabling of data collection after an SAA passage.
The time-averaged spectrum from T-1.42 to T+46.40 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.85 +- 0.06. The fluence in the 15-150 keV band is 3.8 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T-0.30 sec in the 15-150 keV band is 4.3 +- 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/736843/BA/
GCN Circular #20614
D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, P. Oleynik, M. Ulanov, A. Tsvetkova, A. Lysenko, A. Kozlova, and T. Cline on behalf of the Konus-Wind team, report:
The long-duration GRB 170205A (Swift-BAT detection: Troja et al., GCN Circ. 20603), triggered Konus-Wind at T0=45549.824 s UT (12:39:09.824).
The burst light curve shows a double-peaked structure which started at ~T0-32 s and had a total duration of ~56 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/GRB170205_T45549/
As observed by Konus-Wind, the burst had a fluence of 1.22(-0.20,+0.24)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0-0.220 s, of 3.29(-1.62,+1.99)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+24.832 s) is best fit in the 20 keV - 10 MeV range by a power law with spectral index = -2.19(-0.12,+0.13) (chi2 = 58/69 dof). Fitting this spectrum by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) yields alpha = -1.75 (-0.24,+0.62) and an upper limit on Ep of 75 keV (chi2 = 56/68 dof). For the CPL model, the burst fluence is 6.2(-0.8,+1.4)x10^-6 erg/cm2, and the 64-ms peak flux is 1.8(-0.8,+2.8)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
GCN Circular #20615
S.W.K. Emery (UCL-MSSL), E. Troja (NASA/GSFC/UMCP) and A.A. Breeveld (UCL-MSSL) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 170205A 314 s after the BAT trigger (Troja et al., GCN Circ. 20603). A source consistent with the XRT position (Beardmore et al. GCN Circ. 20610) and also detected by Guidorzi et al. GCN 20605, Butler et al. GCN 20609 and Kruehler et al. GCN 20612 is detected in the initial UVOT exposures.
The preliminary UVOT position is: RA (J2000) = 17:28:40.69 = 262.16955 (deg.) Dec (J2000) = -00:03:47.3 = -0.06313 (deg.) with an estimated uncertainty of 0.43 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(FC)       314             464           147        17.52 +/- 0.04
u(FC)                520             540             19        17.30 +/- 0.22
white             4361           4561          197         20.84 +/- 0.33
v                         619        17292        1101        >20.3
b                         545             565             19         17.79 +/- 0.24
u                      3951        12169          785         20.65 +/- 0.33
w1                     496        10592          924        >20.6
m2                  6287        17909          741        >20.6
w2                  4567        16378        1082        >21.1
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.35 in the direction of the burst (Schlegel et al. 1998).

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Jochen Greiner, last update: 06-Feb-2017 [Disclaimer]