Gamma-ray Burst 210217A

(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 17 Feb 21 23:26:06 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     1033264,   Seg_Num: 0
GRB_RA:           97.610d {+06h 30m 26s} (J2000),
                  98.180d {+06h 32m 43s} (current),
                  96.260d {+06h 25m 02s} (1950)
GRB_DEC:         +68.715d {+68d 42' 53"} (J2000),
                 +68.699d {+68d 41' 55"} (current),
                 +68.748d {+68d 44' 54"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       3791 [cnts]    Image_Peak=296 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   150     E_range: 25-100 keV
BKG_INTEN:       18443 [cnts]
BKG_TIME:        84325.47 SOD {23:25:25.47} UT
BKG_DUR:         8 [sec]
GRB_DATE:        19262 TJD;    48 DOY;   21/02/17
GRB_TIME:        84342.30 SOD {23:25:42.30} UT
GRB_PHI:         174.95 [deg]
GRB_THETA:        45.68 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     30.16 [sigma]
IMAGE_SIGNIF:    13.81 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  +3  +0  +0 +39  +0 
SUN_POSTN:       331.64d {+22h 06m 33s}  -11.64d {-11d 38' 09"}
SUN_DIST:        113.56 [deg]   Sun_angle= -8.4 [hr] (East of Sun)
MOON_POSTN:       38.59d {+02h 34m 22s}  +11.97d {+11d 57' 60"}
MOON_DIST:        68.10 [deg]
MOON_ILLUM:      33 [%]
GAL_COORDS:      146.11, 23.29 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       93.92, 45.38 [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 = 50.77,20.58 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 17 Feb 21 23:27:29 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     1033264,   Seg_Num: 0
POINT_RA:         97.627d {+06h 30m 30s} (J2000)
POINT_DEC:       +68.718d {+68d 43' 06"} (J2000)
IMG_START_DATE:  19262 TJD;    48 DOY;   21/02/17
IMG_START_TIME:  84440.15 SOD {23:27:20.15} UT,   97.8 [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:     Wed 17 Feb 21 23:29:20 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     1033264,   Seg_Num: 0
GRB_RA:           97.610d {+06h 30m 26s} (J2000),
                  98.180d {+06h 32m 43s} (current),
                  96.260d {+06h 25m 02s} (1950)
GRB_DEC:         +68.715d {+68d 42' 53"} (J2000),
                 +68.699d {+68d 41' 55"} (current),
                 +68.748d {+68d 44' 54"} (1950)
GRB_DATE:        19262 TJD;    48 DOY;   21/02/17
GRB_TIME:        84342.30 SOD {23:25:42.30} UT
TRIGGER_INDEX:   150
GRB_PHI:         174.95 [deg]
GRB_THETA:        45.68 [deg]
DELTA_TIME:      77.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     30.16 [sigma]
IMAGE_SIGNIF:    13.81 [sigma]
LC_URL:          sw01033264000msb.lc
SUN_POSTN:       331.64d {+22h 06m 33s}  -11.64d {-11d 38' 06"}
SUN_DIST:        113.56 [deg]   Sun_angle= -8.4 [hr] (East of Sun)
MOON_POSTN:       38.62d {+02h 34m 28s}  +11.98d {+11d 58' 36"}
MOON_DIST:        68.08 [deg]
MOON_ILLUM:      33 [%]
GAL_COORDS:      146.11, 23.29 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       93.92, 45.38 [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 = 50.77,20.58 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 17 Feb 21 23:30:22 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1033264,   Seg_Num: 0
POINT_RA:         97.627d {+06h 30m 31s} (J2000)
POINT_DEC:       +68.719d {+68d 43' 09"} (J2000)
POINT_ROLL:      300.297d
IMG_START_DATE:  19262 TJD;    48 DOY;   21/02/17
IMG_START_TIME:  84445.46 SOD {23:27:25.46} UT,   103.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.748
N_STARS:         97
X_OFFSET:        468 [pixels]
Y_OFFSET:        483 [pixels]
X_MAX:           1427 [pixels]
Y_MAX:           1442 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw01033264000msufc0103.fits
SUN_POSTN:       331.64d {+22h 06m 34s}  -11.64d {-11d 38' 05"}
SUN_DIST:        113.57 [deg]   Sun_angle= -8.4 [hr] (East of Sun)
MOON_POSTN:       38.62d {+02h 34m 30s}  +11.98d {+11d 58' 47"}
MOON_DIST:        68.08 [deg]
MOON_ILLUM:      33 [%]
GAL_COORDS:      146.10, 23.29 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       93.93, 45.38 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 17 Feb 21 23:30:36 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1033264,   Seg_Num: 0
POINT_RA:         97.627d {+06h 30m 31s} (J2000)
POINT_DEC:       +68.719d {+68d 43' 09"} (J2000)
POINT_ROLL:      300.297d
IMG_START_DATE:  19262 TJD;    48 DOY;   21/02/17
IMG_START_TIME:  84445.46 SOD {23:27:25.46} UT,   103.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.748
N_STARS:         97
X_OFFSET:        468 [pixels]
Y_OFFSET:        483 [pixels]
X_MAX:           1427 [pixels]
Y_MAX:           1442 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw01033264000msufc0103.fits
SUN_POSTN:       331.64d {+22h 06m 34s}  -11.64d {-11d 38' 05"}
SUN_DIST:        113.57 [deg]   Sun_angle= -8.4 [hr] (East of Sun)
MOON_POSTN:       38.63d {+02h 34m 30s}  +11.98d {+11d 58' 50"}
MOON_DIST:        68.08 [deg]
MOON_ILLUM:      33 [%]
GAL_COORDS:      146.10, 23.29 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       93.93, 45.38 [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 17 Feb 21 23:31:49 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1033264,   Seg_Num: 0
POINT_RA:         97.627d {+06h 30m 31s} (J2000)
POINT_DEC:       +68.719d {+68d 43' 09"} (J2000)
ROLL:            300.297d
IMG_START_DATE:  19262 TJD;    48 DOY;   21/02/17
IMG_START_TIME:  84445.46 SOD {23:27:25.46} UT,   103.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     635297271
X_OFFSET:        787 [pixels]
Y_OFFSET:        802 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       947
Y_GRB_POS:       962
BINNING_INDEX:   1
IM_URL:          sw01033264000msuni0130.fits
SUN_POSTN:       331.64d {+22h 06m 34s}  -11.63d {-11d 38' 04"}
SUN_DIST:        113.56 [deg]   Sun_angle= -8.4 [hr] (East of Sun)
MOON_POSTN:       38.63d {+02h 34m 32s}  +11.98d {+11d 59' 03"}
MOON_DIST:        68.07 [deg]
MOON_ILLUM:      33 [%]
GAL_COORDS:      146.10, 23.29 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       93.93, 45.38 [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 17 Feb 21 23:31:07 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     1033264,   Seg_Num: 0
GRB_RA:           97.5876d {+06h 30m 21.02s} (J2000),
                  98.1575d {+06h 32m 37.80s} (current),
                  96.2367d {+06h 24m 56.80s} (1950)
GRB_DEC:         +68.7247d {+68d 43' 28.9"} (J2000),
                 +68.7086d {+68d 42' 30.9"} (current),
                 +68.7582d {+68d 45' 29.5"} (1950)
GRB_ERROR:       3.8 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  19262 TJD;    48 DOY;   21/02/17
IMG_START_TIME:  84451.00 SOD {23:27:31.00} UT,   108.7 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       331.64d {+22h 06m 34s}  -11.63d {-11d 38' 05"}
SUN_DIST:        113.55 [deg]   Sun_angle= -8.4 [hr] (East of Sun)
MOON_POSTN:       38.63d {+02h 34m 31s}  +11.98d {+11d 58' 55"}
MOON_DIST:        68.06 [deg]
MOON_ILLUM:      33 [%]
GAL_COORDS:      146.09, 23.28 [deg] galactic lon,lat of the burst
ECL_COORDS:       93.91, 45.39 [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 17 Feb 21 23:32:03 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1033264,   Seg_Num: 0
POINT_RA:         97.627d {+06h 30m 31s} (J2000)
POINT_DEC:       +68.719d {+68d 43' 09"} (J2000)
ROLL:            300.297d
IMG_START_DATE:  19262 TJD;    48 DOY;   21/02/17
IMG_START_TIME:  84445.46 SOD {23:27:25.46} UT,   103.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     635297271
X_OFFSET:        787 [pixels]
Y_OFFSET:        802 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       947
Y_GRB_POS:       962
BINNING_INDEX:   1
IM_URL:          sw01033264000msuni0130.fits
SUN_POSTN:       331.64d {+22h 06m 34s}  -11.63d {-11d 38' 04"}
SUN_DIST:        113.56 [deg]   Sun_angle= -8.4 [hr] (East of Sun)
MOON_POSTN:       38.64d {+02h 34m 33s}  +11.98d {+11d 59' 06"}
MOON_DIST:        68.07 [deg]
MOON_ILLUM:      33 [%]
GAL_COORDS:      146.10, 23.29 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       93.93, 45.38 [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 17 Feb 21 23:33:37 UT
NOTICE_TYPE:     Swift-UVOT Position
TRIGGER_NUM:     1033264,   Seg_Num: 0
GRB_RA:           97.5830d {+06h 30m 19.91s} (J2000),
                  98.1529d {+06h 32m 36.70s} (current),
                  96.2321d {+06h 24m 55.69s} (1950)
GRB_DEC:         +68.7251d {+68d 43' 30.3"} (J2000),
                 +68.7090d {+68d 42' 32.3"} (current),
                 +68.7586d {+68d 45' 30.9"} (1950)
GRB_ERROR:       0.6 [arcsec radius, statistical only]
GRB_MAG:         18.71 +/- 0.14 [mag]
FILTER:          10, White
IMG_START_DATE:  19262 TJD;    48 DOY;   21/02/17
IMG_START_TIME:  84442.00 SOD {23:27:22.00} UT,   99.7 [sec] since BAT Trigger Time
SUN_POSTN:       331.64d {+22h 06m 34s}  -11.63d {-11d 38' 03"}
SUN_DIST:        113.55 [deg]   Sun_angle= -8.4 [hr] (East of Sun)
MOON_POSTN:       38.65d {+02h 34m 36s}  +11.99d {+11d 59' 23"}
MOON_DIST:        68.05 [deg]
MOON_ILLUM:      33 [%]
GAL_COORDS:      146.09, 23.28 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       93.91, 45.39 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT UVOT Position Notice.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        Result based on Genie data.  
COMMENTS:        Notice generated automatically.

GCN Circular #29521
K. K. Simpson (PSU), J.D. Gropp (PSU), J. A. Kennea (PSU), N. J. Klingler (PSU), N. P. M. Kuin (UCL-MSSL), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), M. J. Moss (GWU), D. M. Palmer (LANL), B. Sbarufatti (PSU) and M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift Observatory Team:
At 23:25:42 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 210217A (trigger=1033264). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 97.610, +68.715 which is
```
   RA(J2000) = 06h 30m 26s
   Dec(J2000) = +68d 42' 53"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peaked structure with a duration of about 5 sec. The peak count rate was ~3400 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 23:27:20.1 UT, 97.8 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source located at RA, Dec 97.58675, 68.72497 which is equivalent to:
```
   RA(J2000)  = 06h 30m 20.82s
   Dec(J2000) = +68d 43' 29.9"
```
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 47 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 https://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 8.69 x 10^20 cm^-2 (Willingale et al. 2013).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 103 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at
```
  RA(J2000)  =	06:30:19.93 =  97.58305
  DEC(J2000) = +68:43:30.6  =  68.72516
```
with a 90%-confidence error radius of about 0.63 arc sec. This position is 6.2 arc sec. from the center of the XRT error circle. The estimated magnitude is 18.72 with a 1-sigma error of about 0.15. No correction has been made for the expected extinction corresponding to E(B-V) of 0.103.
Burst Advocate for this burst is K. K. Simpson (kira.simpson1984 AT gmail.com). 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/)

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 17 Feb 21 23:37:47 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1033264,   Seg_Num: 0
POINT_RA:         97.632d {+06h 30m 32s} (J2000)
POINT_DEC:       +68.721d {+68d 43' 15"} (J2000)
POINT_ROLL:      300.303d
IMG_START_DATE:  19262 TJD;    48 DOY;   21/02/17
IMG_START_TIME:  84657.49 SOD {23:30:57.49} UT,   315.2 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.399
N_STARS:         99
X_OFFSET:        228 [pixels]
Y_OFFSET:        243 [pixels]
X_MAX:           1667 [pixels]
Y_MAX:           1682 [pixels]
DET_THRESH:      6
PHOTO_THRESH:    2
SL_URL:          sw01033264000msufc0315.fits
SUN_POSTN:       331.64d {+22h 06m 35s}  -11.63d {-11d 37' 59"}
SUN_DIST:        113.56 [deg]   Sun_angle= -8.4 [hr] (East of Sun)
MOON_POSTN:       38.68d {+02h 34m 44s}  +12.00d {+12d 00' 10"}
MOON_DIST:        68.04 [deg]
MOON_ILLUM:      33 [%]
GAL_COORDS:      146.10, 23.30 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       93.94, 45.39 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Wed 17 Feb 21 23:38:52 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1033264,   Seg_Num: 0
POINT_RA:         97.632d {+06h 30m 32s} (J2000)
POINT_DEC:       +68.721d {+68d 43' 15"} (J2000)
ROLL:            300.303d
IMG_START_DATE:  19262 TJD;    48 DOY;   21/02/17
IMG_START_TIME:  84657.49 SOD {23:30:57.49} UT,   315.2 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     635297484
X_OFFSET:        787 [pixels]
Y_OFFSET:        802 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       947
Y_GRB_POS:       962
BINNING_INDEX:   1
IM_URL:          sw01033264000msuni0342.fits
SUN_POSTN:       331.65d {+22h 06m 35s}  -11.63d {-11d 37' 58"}
SUN_DIST:        113.56 [deg]   Sun_angle= -8.4 [hr] (East of Sun)
MOON_POSTN:       38.69d {+02h 34m 46s}  +12.01d {+12d 00' 22"}
MOON_DIST:        68.04 [deg]
MOON_ILLUM:      33 [%]
GAL_COORDS:      146.10, 23.30 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       93.94, 45.39 [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 17 Feb 21 23:38:04 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1033264,   Seg_Num: 0
POINT_RA:         97.632d {+06h 30m 32s} (J2000)
POINT_DEC:       +68.721d {+68d 43' 15"} (J2000)
POINT_ROLL:      300.303d
IMG_START_DATE:  19262 TJD;    48 DOY;   21/02/17
IMG_START_TIME:  84657.49 SOD {23:30:57.49} UT,   315.2 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.399
N_STARS:         99
X_OFFSET:        228 [pixels]
Y_OFFSET:        243 [pixels]
X_MAX:           1667 [pixels]
Y_MAX:           1682 [pixels]
DET_THRESH:      6
PHOTO_THRESH:    2
SL_URL:          sw01033264000msufc0315.fits
SUN_POSTN:       331.65d {+22h 06m 35s}  -11.63d {-11d 37' 59"}
SUN_DIST:        113.56 [deg]   Sun_angle= -8.4 [hr] (East of Sun)
MOON_POSTN:       38.68d {+02h 34m 44s}  +12.00d {+12d 00' 13"}
MOON_DIST:        68.04 [deg]
MOON_ILLUM:      33 [%]
GAL_COORDS:      146.10, 23.30 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       93.94, 45.39 [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 17 Feb 21 23:38:14 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     1033264,   Seg_Num: 0
GRB_RA:           97.5833d {+06h 30m 19.99s} (J2000),
                  98.1532d {+06h 32m 36.77s} (current),
                  96.2324d {+06h 24m 55.76s} (1950)
GRB_DEC:         +68.7250d {+68d 43' 29.9"} (J2000),
                 +68.7089d {+68d 42' 32.0"} (current),
                 +68.7585d {+68d 45' 30.5"} (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:  19262 TJD;    48 DOY;   21/02/17
IMG_START_TIME:  84451.00 SOD {23:27:31.00} UT,   108.7 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       331.65d {+22h 06m 35s}  -11.63d {-11d 37' 59"}
SUN_DIST:        113.55 [deg]   Sun_angle= -8.4 [hr] (East of Sun)
MOON_POSTN:       38.68d {+02h 34m 44s}  +12.00d {+12d 00' 15"}
MOON_DIST:        68.02 [deg]
MOON_ILLUM:      33 [%]
GAL_COORDS:      146.09, 23.28 [deg] galactic lon,lat of the burst
ECL_COORDS:       93.91, 45.39 [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 17 Feb 21 23:39:06 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1033264,   Seg_Num: 0
POINT_RA:         97.632d {+06h 30m 32s} (J2000)
POINT_DEC:       +68.721d {+68d 43' 15"} (J2000)
ROLL:            300.303d
IMG_START_DATE:  19262 TJD;    48 DOY;   21/02/17
IMG_START_TIME:  84657.49 SOD {23:30:57.49} UT,   315.2 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     635297484
X_OFFSET:        787 [pixels]
Y_OFFSET:        802 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       947
Y_GRB_POS:       962
BINNING_INDEX:   1
IM_URL:          sw01033264000msuni0342.fits
SUN_POSTN:       331.65d {+22h 06m 35s}  -11.63d {-11d 37' 58"}
SUN_DIST:        113.56 [deg]   Sun_angle= -8.4 [hr] (East of Sun)
MOON_POSTN:       38.69d {+02h 34m 46s}  +12.01d {+12d 00' 24"}
MOON_DIST:        68.03 [deg]
MOON_ILLUM:      33 [%]
GAL_COORDS:      146.10, 23.30 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       93.94, 45.39 [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 #29523
Z.P. Zhu (NAOC, HUST), S.Y. Fu, X. Liu, D. Xu (NAOC), X. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report:
We observed the field of GRB 210217A (Simpson et al., GCN 29521) using the NEXT-0.6m optical telescope located at Nanshan, Xinjiang, China. Observations automatically started at 23:27:06 UT on 2021-02-17, i.e., 84 s after the BAT trigger. A series of 3x40 s, 4x60 s and 10x90 s frames in the Sloan r-filter have been obtained, and observations are ongoing.
An uncatalogued decaying optical transient is detected at the Swift/UVOT position (Simpson et al., GCN 29521), which is thus concluded to be the optical afterglow of burst. The afterglow has r = 18.6 +/- 0.2 mag in our first image, calibrated with nearby PS1 stars.
GCN Circular #29525
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team.
Using 396 s of XRT Photon Counting mode data and 1 UVOT images for GRB 210217A, 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 = 97.58507, +68.72536 which is equivalent to:
```
RA (J2000): 06h 30m 20.42s
Dec (J2000): +68d 43' 31.3"
```
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 #29533
WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on behalf of the KAIT GRB team:

The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at
Lick Observatory, responded to the Swift GRB 210217A (Simpson et al.,
GCN 29521) starting at ~4.27 hours after the Swift trigger.
A total of 30x60s images were obtained in the clear (roughly R) filters.
We marginally detect the optical afterglow (Simpson et al., GCN 29521;
Zhu et al., GCN 29523) in the coadd image with a mag of 20.8 +/- 0.3,
calibrated to the Pan-STARRS1 catalog.
GCN Circular #29534
T. Sakamoto (AGU), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), K. K. Simpson (PSU), 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 210217A (trigger #1033264) (Simpson et al., GCN Circ. 29521). The BAT ground-calculated position is RA, Dec = 97.578, 68.715 deg which is
```
   RA(J2000)  =  06h 30m 18.6s
   Dec(J2000) = +68d 42' 55.4"
```
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 30%.
The mask-weighted light curve shows a single-peaked FRED-like structure that starts and peaks at ~T0, and ends at ~T+5 s. T90 (15-350 keV) is 4.22 +- 1.15 sec (estimated error including systematics).
The time-averaged spectrum from T-0.65 to T+4.89 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.01 +- 0.16. The fluence in the 15-150 keV band is 6.8 +- 0.7 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T-0.13 sec in the 15-150 keV band is 5.1 +- 0.5 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/1033264/BA/
GCN Circular #29535
M. Shrestha (Liverpool JMU), R. Smith (LJMU) , A. Melandri (INAF), I.A. Steele (LJMU), S. Kobayashi (LJMU), C. Mundell (Univ. Bath), A. Gomboc (Univ. Nova Gorica), C. Guidorzi (Univ. Ferrara) report on behalf of a wider collaboration:
We observed the field of Swift GRB 210217A (GCN 29521) with the 2.0m Liverpool Telescope (LT), La Palma on 2021 Feb 17 starting at 23:28:51.056 UT
using the IO:O optical camera in the r=92, i=92, and z=92 bands. Data were calibrated with respect to nearby APASS secondary standard stars for r=92 and i=92 bands
and SDSS secondary standard stars for z=92 band. We confirm the optical counterpart reported by Swift UVOT and NEXT (GCN 29523).
At T=3D194 seconds after the BAT trigger time, we measure r=92 =3D 18.51 +/- 0.3 mag which is close to 18.6 +/- 0.2 mag detected by NEXT team (GCN 29523).
The r=92 band light curve made with IO:O observations show a power law decay over the first hour in flux vs time with alpha =3D 0.48.
At T =3D 690 seconds after the BAT trigger time, we measure i=92 =3D 18.77 +/- 0.1 mag and at T =3D 868 seconds after the trigger we measure z=92 =3D 18.67 +/-0.1 mag.
________________________________
Important Notice: Liverpool John Moores University was established as a Hig= her Education Corporation under section 121 of the Education Reform Act 198= 8. Further information about Liverpool John Moores University can be found = at https://www.ljmu.ac.uk/about-us The information in this email and any at= tachments is for the sole use of the intended recipient(s). If you are not = an intended recipient, or a person responsible for delivering it to an inte= nded recipient, you should delete it from your system immediately without d= isclosing its contents elsewhere and advise the sender by returning the ema= il or by telephoning a number contained in the body of the email. No respon= sibility is accepted for loss or damage arising from viruses or changes mad= e to this message after it was sent and the recipient must ensure that the = email (and attachments) are virus free. The views contained in this email a= re those of the author and not necessarily those of Liverpool John Moores U= niversity. We will use the personal data information provided by you to res= pond to your email. For information about how we process personal data and = monitor communications please see our Privacy Notice. https://www.ljmu.ac.uk/legal/privacy-and-cookies
GCN Circular #29536
C. Fletcher (USRA) reports on behalf of the Fermi-GBM Team:
Swift-BAT detected GRB 210217A at 23:25:42 UT (GCN 29521). There was no Fermi-GBM onboard trigger around the event.
An automated, blind search for short gamma-ray bursts below the onboard triggering threshold in Fermi-GBM identified a high reliability transient consistent in both time and location with the Swift BAT event. Link: https://gcn.gsfc.nasa.gov/notices_gbm_sub/635297147.fermi
The GBM targeted search [1], the most sensitive, coherent search for GRB-like signals also identified a transient most significantly on the 1.024 s timescale, with a log likelihood ratio of 72 and a location consistent with the Swift BAT event. The GBM targeted search event was found with the highest significance with a "normal" spectrum (Band function with Epeak = 230 keV, alpha = -1.0, beta = -2.3) for a GRB.
[1] Goldstein et al. 2019 arXiv:1903.12597
GCN Circular #29538
D.N. Burrows (PSU), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , J. D. Gropp (PSU), J.A. Kennea (PSU) and K.K. Simpson report on behalf of the Swift-XRT team:
We have analysed 6.8 ks of XRT data for GRB 210217A (Simpson et al. GCN Circ. 29521), from 109 s to 80.4 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Evans et al. (GCN Circ. 29525).
The light curve can be modelled with a power-law decay with a decay index of alpha=0.79 (+/-0.05).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.97 (+0.23, -0.22). The best-fitting absorption column is 2.5 (+0.9, -0.8) x 10^21 cm^-2, in excess of the Galactic value of 8.7 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.7 x 10^-11 (5.1 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     2.5 (+0.9, -0.8) x 10^21 cm^-2
Galactic foreground: 8.7 x 10^20 cm^-2
Excess significance: 3.3 sigma
Photon index:	     1.97 (+0.23, -0.22)
```
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01033264.
This circular is an official product of the Swift-XRT team.
GCN Circular #29539
Amit Kumar (ARIES), Rahul Gupta (ARIES), Ankur Ghosh (ARIES), Dimple (ARIES), Tushar Tripathi (ARIES), Shubham Kishore (ARIES), Amar Aryan (ARIES), Shashi B. Pandey (ARIES), Brajesh Kumar (ARIES), and Kuntal Misra (ARIES) report:
We observed the optical afterglow of the Swift detected GRB 210217A (Simpson et al. GCN 29521; Evans et al., GCN 29525) with the 1.3m Devsthal Fast Optical Telescope (DFOT) at Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital (India), on 2021-02-18 from UT 17:31:22 to 19:09:31 (corresponding to 18.094 to 19.730 hours from the GRB trigger time). We observed a series of 30x120s exposures in the Bessel R filter and a series of 20x120s exposures in the Bessel I filter. We clearly detected the optical afterglow of GRB 210217A in the stacked frames within the Swift XRT error circle (Simpson et al. GCN 29521) as also reported by Zhu et al., GCN 29523; Zheng & Filippenko GCN 29533; Shrestha et al. GCN 29535.
The estimated preliminary magnitudes are as follows:
```
T_start-T0 (hours) Start Date (UTC) Filter Magnitude (mag)
-----------------------------------------------------------
-----------------------------------------------------------
18.09 2021-02-18T17:31:22 R 21.80 +- 0.08
19.73 2021-02-18T19:09:31 I 21.56 +- 0.12
```
The magnitudes are not corrected for the Galactic extinction in the direction of the burst. Photometric calibration is performed using the standard stars from the USNO-B1.0 catalog.
This circular may be cited.
GCN Circular #29555
GRB 210217A: Swift/UVOT Detection
K. K. Simpson (PSU) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 210217A 103 s after the BAT trigger (Simpson et al., GCN Circ. 29521). A source consistent with the XRT position *** POSITION REFERENCE is GCN_Notice *** is detected in the initial UVOT exposures.
The preliminary UVOT position is:
```
    RA  (J2000) =  06:30:19.90 =  97.58291 (deg.)
    Dec (J2000) = +68:43:30.6  =  68.72517 (deg.)
```
with an estimated uncertainty of 0.46 arc sec. (radius, 90% confidence).
Preliminary detections 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              103          253          147         18.80 +/- 0.06
u                  315          508          190         18.64 +/- 0.11
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.102 in the direction of the burst (Schlegel et al. 1998).

Back to JG's homepage

Jochen Greiner, last update: 23-Feb-2021 [Disclaimer]