Gamma-ray Burst 210305A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 05 Mar 21 19:03:18 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     1035922,   Seg_Num: 0
GRB_RA:          319.814d {+21h 19m 15s} (J2000),
                 320.033d {+21h 20m 08s} (current),
                 319.297d {+21h 17m 11s} (1950)
GRB_DEC:         +34.557d {+34d 33' 24"} (J2000),
                 +34.647d {+34d 38' 49"} (current),
                 +34.345d {+34d 20' 41"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       4041 [cnts]    Image_Peak=382 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   146     E_range: 25-100 keV
BKG_INTEN:       18822 [cnts]
BKG_TIME:        68565.38 SOD {19:02:45.38} UT
BKG_DUR:         8 [sec]
GRB_DATE:        19278 TJD;    64 DOY;   21/03/05
GRB_TIME:        68584.45 SOD {19:03:04.45} UT
GRB_PHI:         -128.02 [deg]
GRB_THETA:        25.07 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     31.20 [sigma]
IMAGE_SIGNIF:    14.41 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  +3  +0  +0 -67  +0 
SUN_POSTN:       346.59d {+23h 06m 20s}   -5.74d {-05d 44' 31"}
SUN_DIST:         47.52 [deg]   Sun_angle= 1.8 [hr] (West of Sun)
MOON_POSTN:      250.33d {+16h 41m 19s}  -21.81d {-21d 48' 38"}
MOON_DIST:        86.92 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:       80.92,-10.49 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      337.40, 47.04 [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 = 203.80,-18.27 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 05 Mar 21 19:05:01 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     1035922,   Seg_Num: 0
GRB_RA:          319.8085d {+21h 19m 14.0s} (J2000),
                 320.0275d {+21h 20m 06.5s} (current),
                 319.2919d {+21h 17m 10.0s} (1950)
GRB_DEC:         +34.5544d {+34d 33' 15.8"} (J2000),
                 +34.6446d {+34d 38' 40.5"} (current),
                 +34.3425d {+34d 20' 33.1"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       81 [cnts]
IMG_START_DATE:  19278 TJD;    64 DOY;   21/03/05
IMG_START_TIME:  68661.28 SOD {19:04:21.28} UT,   76.8 [sec] since BAT Trigger Time
CENTROID_X:      257.28,  raw= 257  [pixels]
CENTROID_Y:      294.07,  raw= 294  [pixels]
ROLL:            142.56 [deg]
GAIN:            2
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -9.48
GRB_POS_XRT_Z:   -118.12
IMAGE_URL:       sw01035922000msxps_rw.img
SUN_POSTN:       346.59d {+23h 06m 21s}   -5.74d {-05d 44' 29"}
SUN_DIST:         47.52 [deg]   Sun_angle= 1.8 [hr] (West of Sun)
MOON_POSTN:      250.35d {+16h 41m 23s}  -21.81d {-21d 48' 52"}
MOON_DIST:        86.91 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:       80.91,-10.48 [deg] galactic lon,lat of the burst
ECL_COORDS:      337.39, 47.04 [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:     Fri 05 Mar 21 19:05:05 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     1035922,   Seg_Num: 0
GRB_RA:          319.8085d {+21h 19m 14.0s} (J2000),
                 320.0275d {+21h 20m 06.5s} (current),
                 319.2919d {+21h 17m 10.0s} (1950)
GRB_DEC:         +34.5544d {+34d 33' 15.8"} (J2000),
                 +34.6446d {+34d 38' 40.5"} (current),
                 +34.3425d {+34d 20' 33.1"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       81 [cnts]
IMG_START_DATE:  19278 TJD;    64 DOY;   21/03/05
IMG_START_TIME:  68661.28 SOD {19:04:21.28} UT,   76.8 [sec] since BAT Trigger Time
CENTROID_X:      257.28,  raw= 257  [pixels]
CENTROID_Y:      294.07,  raw= 294  [pixels]
ROLL:            142.56 [deg]
GAIN:            2
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   -9.48
GRB_POS_XRT_Z:   -118.12
IMAGE_URL:       sw01035922000msxps_rw.img
SUN_POSTN:       346.59d {+23h 06m 21s}   -5.74d {-05d 44' 29"}
SUN_DIST:         47.52 [deg]   Sun_angle= 1.8 [hr] (West of Sun)
MOON_POSTN:      250.35d {+16h 41m 23s}  -21.81d {-21d 48' 52"}
MOON_DIST:        86.91 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:       80.91,-10.48 [deg] galactic lon,lat of the burst
ECL_COORDS:      337.39, 47.04 [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:     Fri 05 Mar 21 19:04:51 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     1035922,   Seg_Num: 0
GRB_RA:          319.8085d {+21h 19m 14.03s} (J2000),
                 320.0275d {+21h 20m 06.59s} (current),
                 319.2919d {+21h 17m 10.05s} (1950)
GRB_DEC:         +34.5544d {+34d 33' 15.8"} (J2000),
                 +34.6446d {+34d 38' 40.5"} (current),
                 +34.3425d {+34d 20' 33.1"} (1950)
GRB_ERROR:       5.0 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       2.86e-09 [erg/cm2/sec]
GRB_SIGNIF:      9.00 [sigma]
IMG_START_DATE:  19278 TJD;    64 DOY;   21/03/05
IMG_START_TIME:  68661.28 SOD {19:04:21.28} UT,   76.8 [sec] since BAT Trigger Time
TAM[0-3]:        327.67 237.18 261.59 243.50
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       346.59d {+23h 06m 21s}   -5.74d {-05d 44' 29"}
SUN_DIST:         47.52 [deg]   Sun_angle= 1.8 [hr] (West of Sun)
MOON_POSTN:      250.35d {+16h 41m 23s}  -21.81d {-21d 48' 51"}
MOON_DIST:        86.91 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:       80.91,-10.48 [deg] galactic lon,lat of the burst
ECL_COORDS:      337.39, 47.04 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 0.29 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:     Fri 05 Mar 21 19:06:57 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     1035922,   Seg_Num: 0
GRB_RA:          319.814d {+21h 19m 15s} (J2000),
                 320.033d {+21h 20m 08s} (current),
                 319.297d {+21h 17m 11s} (1950)
GRB_DEC:         +34.557d {+34d 33' 24"} (J2000),
                 +34.647d {+34d 38' 49"} (current),
                 +34.345d {+34d 20' 41"} (1950)
GRB_DATE:        19278 TJD;    64 DOY;   21/03/05
GRB_TIME:        68584.45 SOD {19:03:04.45} UT
TRIGGER_INDEX:   146
GRB_PHI:         -128.02 [deg]
GRB_THETA:        25.07 [deg]
DELTA_TIME:      12.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     31.20 [sigma]
IMAGE_SIGNIF:    14.41 [sigma]
LC_URL:          sw01035922000msb.lc
SUN_POSTN:       346.59d {+23h 06m 21s}   -5.74d {-05d 44' 27"}
SUN_DIST:         47.52 [deg]   Sun_angle= 1.8 [hr] (West of Sun)
MOON_POSTN:      250.37d {+16h 41m 28s}  -21.82d {-21d 49' 07"}
MOON_DIST:        86.90 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:       80.92,-10.49 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      337.40, 47.04 [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 = 203.80,-18.27 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 05 Mar 21 19:08:41 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1035922,   Seg_Num: 0
POINT_RA:        319.788d {+21h 19m 09s} (J2000)
POINT_DEC:       +34.582d {+34d 34' 55"} (J2000)
POINT_ROLL:      142.565d
IMG_START_DATE:  19278 TJD;    64 DOY;   21/03/05
IMG_START_TIME:  68669.54 SOD {19:04:29.54} UT,   85.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.127
N_STARS:         190
X_OFFSET:        688 [pixels]
Y_OFFSET:        416 [pixels]
X_MAX:           1647 [pixels]
Y_MAX:           1375 [pixels]
DET_THRESH:      19
PHOTO_THRESH:    11
SL_URL:          sw01035922000msufc0085.fits
SUN_POSTN:       346.59d {+23h 06m 21s}   -5.74d {-05d 44' 26"}
SUN_DIST:         47.55 [deg]   Sun_angle= 1.8 [hr] (West of Sun)
MOON_POSTN:      250.38d {+16h 41m 32s}  -21.82d {-21d 49' 20"}
MOON_DIST:        86.88 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:       80.92,-10.45 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      337.38, 47.07 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 05 Mar 21 19:08:56 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1035922,   Seg_Num: 0
POINT_RA:        319.788d {+21h 19m 09s} (J2000)
POINT_DEC:       +34.582d {+34d 34' 55"} (J2000)
POINT_ROLL:      142.565d
IMG_START_DATE:  19278 TJD;    64 DOY;   21/03/05
IMG_START_TIME:  68669.54 SOD {19:04:29.54} UT,   85.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.127
N_STARS:         190
X_OFFSET:        688 [pixels]
Y_OFFSET:        416 [pixels]
X_MAX:           1647 [pixels]
Y_MAX:           1375 [pixels]
DET_THRESH:      19
PHOTO_THRESH:    11
SL_URL:          sw01035922000msufc0085.fits
SUN_POSTN:       346.59d {+23h 06m 21s}   -5.74d {-05d 44' 25"}
SUN_DIST:         47.55 [deg]   Sun_angle= 1.8 [hr] (West of Sun)
MOON_POSTN:      250.39d {+16h 41m 33s}  -21.82d {-21d 49' 22"}
MOON_DIST:        86.88 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:       80.92,-10.45 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      337.38, 47.07 [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:     Fri 05 Mar 21 19:10:48 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1035922,   Seg_Num: 0
POINT_RA:        319.788d {+21h 19m 09s} (J2000)
POINT_DEC:       +34.582d {+34d 34' 55"} (J2000)
ROLL:            142.565d
IMG_START_DATE:  19278 TJD;    64 DOY;   21/03/05
IMG_START_TIME:  68669.54 SOD {19:04:29.54} UT,   85.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     636663896
X_OFFSET:        1015 [pixels]
Y_OFFSET:        764 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1175
Y_GRB_POS:       924
BINNING_INDEX:   1
IM_URL:          sw01035922000msuni0112.fits
SUN_POSTN:       346.59d {+23h 06m 22s}   -5.74d {-05d 44' 24"}
SUN_DIST:         47.55 [deg]   Sun_angle= 1.8 [hr] (West of Sun)
MOON_POSTN:      250.41d {+16h 41m 38s}  -21.83d {-21d 49' 37"}
MOON_DIST:        86.87 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:       80.92,-10.45 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      337.38, 47.07 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 05 Mar 21 19:11:01 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1035922,   Seg_Num: 0
POINT_RA:        319.788d {+21h 19m 09s} (J2000)
POINT_DEC:       +34.582d {+34d 34' 55"} (J2000)
ROLL:            142.565d
IMG_START_DATE:  19278 TJD;    64 DOY;   21/03/05
IMG_START_TIME:  68669.54 SOD {19:04:29.54} UT,   85.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     636663896
X_OFFSET:        1015 [pixels]
Y_OFFSET:        764 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1175
Y_GRB_POS:       924
BINNING_INDEX:   1
IM_URL:          sw01035922000msuni0112.fits
SUN_POSTN:       346.59d {+23h 06m 22s}   -5.74d {-05d 44' 23"}
SUN_DIST:         47.55 [deg]   Sun_angle= 1.8 [hr] (West of Sun)
MOON_POSTN:      250.41d {+16h 41m 38s}  -21.83d {-21d 49' 39"}
MOON_DIST:        86.87 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:       80.92,-10.45 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      337.38, 47.07 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 05 Mar 21 19:18:50 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1035922,   Seg_Num: 0
POINT_RA:        319.784d {+21h 19m 08s} (J2000)
POINT_DEC:       +34.582d {+34d 34' 55"} (J2000)
ROLL:            142.562d
IMG_START_DATE:  19278 TJD;    64 DOY;   21/03/05
IMG_START_TIME:  68881.71 SOD {19:08:01.71} UT,   297.3 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     636664108
X_OFFSET:        1015 [pixels]
Y_OFFSET:        764 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1175
Y_GRB_POS:       924
BINNING_INDEX:   1
IM_URL:          sw01035922000msuni0324.fits
SUN_POSTN:       346.60d {+23h 06m 23s}   -5.74d {-05d 44' 16"}
SUN_DIST:         47.56 [deg]   Sun_angle= 1.8 [hr] (West of Sun)
MOON_POSTN:      250.49d {+16h 41m 57s}  -21.84d {-21d 50' 40"}
MOON_DIST:        86.82 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:       80.92,-10.45 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      337.38, 47.07 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 05 Mar 21 19:19:03 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1035922,   Seg_Num: 0
POINT_RA:        319.784d {+21h 19m 08s} (J2000)
POINT_DEC:       +34.582d {+34d 34' 55"} (J2000)
ROLL:            142.562d
IMG_START_DATE:  19278 TJD;    64 DOY;   21/03/05
IMG_START_TIME:  68881.71 SOD {19:08:01.71} UT,   297.3 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     636664108
X_OFFSET:        1015 [pixels]
Y_OFFSET:        764 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1175
Y_GRB_POS:       924
BINNING_INDEX:   1
IM_URL:          sw01035922000msuni0324.fits
SUN_POSTN:       346.60d {+23h 06m 23s}   -5.74d {-05d 44' 16"}
SUN_DIST:         47.56 [deg]   Sun_angle= 1.8 [hr] (West of Sun)
MOON_POSTN:      250.49d {+16h 41m 58s}  -21.85d {-21d 50' 41"}
MOON_DIST:        86.82 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:       80.92,-10.45 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      337.38, 47.07 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN Circular #29595
A. D'Ai (INAF-IASFPA), E. Ambrosi (INAF-IASFPA), V. D'Elia (SSDC), N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift Observatory Team:
At 19:03:04 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 210305A (trigger=1035922). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 319.814, +34.557 which is
```
   RA(J2000) = 21h 19m 15s
   Dec(J2000) = +34d 33' 24"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 100 sec. The peak count rate was ~3200 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 19:04:21.28 UT, 76.8 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with position: RA, Dec 319.80764, 34.554389 which is equivalent to:
```
   RA(J2000)  = 21h 19m 13.83s
   Dec(J2000) = +34d 33' 15.8"
```
with an uncertainty of 4.7 arcseconds (radius, 90% containment). This location is 21 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received.
UVOT took a finding chart exposure of 150 seconds with the White filter starting 85 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 0.155.
Burst Advocate for this burst is A. D'Ai (antonino.dai AT 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/)

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 05 Mar 21 19:24:16 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1035922,   Seg_Num: 0
POINT_RA:        319.784d {+21h 19m 08s} (J2000)
POINT_DEC:       +34.582d {+34d 34' 55"} (J2000)
POINT_ROLL:      142.562d
IMG_START_DATE:  19278 TJD;    64 DOY;   21/03/05
IMG_START_TIME:  69460.38 SOD {19:17:40.38} UT,   875.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.288
N_STARS:         190
X_OFFSET:        455 [pixels]
Y_OFFSET:        204 [pixels]
X_MAX:           1894 [pixels]
Y_MAX:           1643 [pixels]
DET_THRESH:      19
PHOTO_THRESH:    11
SL_URL:          sw01035922000msufc0875.fits
SUN_POSTN:       346.60d {+23h 06m 24s}   -5.74d {-05d 44' 11"}
SUN_DIST:         47.56 [deg]   Sun_angle= 1.8 [hr] (West of Sun)
MOON_POSTN:      250.54d {+16h 42m 11s}  -21.86d {-21d 51' 22"}
MOON_DIST:        86.79 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:       80.92,-10.45 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      337.38, 47.07 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 05 Mar 21 19:24:30 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1035922,   Seg_Num: 0
POINT_RA:        319.784d {+21h 19m 08s} (J2000)
POINT_DEC:       +34.582d {+34d 34' 55"} (J2000)
POINT_ROLL:      142.562d
IMG_START_DATE:  19278 TJD;    64 DOY;   21/03/05
IMG_START_TIME:  69460.38 SOD {19:17:40.38} UT,   875.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.288
N_STARS:         190
X_OFFSET:        455 [pixels]
Y_OFFSET:        204 [pixels]
X_MAX:           1894 [pixels]
Y_MAX:           1643 [pixels]
DET_THRESH:      19
PHOTO_THRESH:    11
SL_URL:          sw01035922000msufc0875.fits
SUN_POSTN:       346.60d {+23h 06m 24s}   -5.74d {-05d 44' 10"}
SUN_DIST:         47.56 [deg]   Sun_angle= 1.8 [hr] (West of Sun)
MOON_POSTN:      250.55d {+16h 42m 11s}  -21.86d {-21d 51' 24"}
MOON_DIST:        86.79 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:       80.92,-10.45 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      337.38, 47.07 [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:     Fri 05 Mar 21 19:26:27 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1035922,   Seg_Num: 0
POINT_RA:        319.784d {+21h 19m 08s} (J2000)
POINT_DEC:       +34.582d {+34d 34' 55"} (J2000)
ROLL:            142.562d
IMG_START_DATE:  19278 TJD;    64 DOY;   21/03/05
IMG_START_TIME:  69460.38 SOD {19:17:40.38} UT,   875.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     636664687
X_OFFSET:        1014 [pixels]
Y_OFFSET:        763 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1174
Y_GRB_POS:       923
BINNING_INDEX:   1
IM_URL:          sw01035922000msuni0902.fits
SUN_POSTN:       346.60d {+23h 06m 24s}   -5.74d {-05d 44' 08"}
SUN_DIST:         47.56 [deg]   Sun_angle= 1.8 [hr] (West of Sun)
MOON_POSTN:      250.57d {+16h 42m 16s}  -21.86d {-21d 51' 39"}
MOON_DIST:        86.77 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:       80.92,-10.45 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      337.38, 47.07 [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:     Fri 05 Mar 21 19:26:41 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1035922,   Seg_Num: 0
POINT_RA:        319.784d {+21h 19m 08s} (J2000)
POINT_DEC:       +34.582d {+34d 34' 55"} (J2000)
ROLL:            142.562d
IMG_START_DATE:  19278 TJD;    64 DOY;   21/03/05
IMG_START_TIME:  69460.38 SOD {19:17:40.38} UT,   875.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     636664687
X_OFFSET:        1014 [pixels]
Y_OFFSET:        763 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1174
Y_GRB_POS:       923
BINNING_INDEX:   1
IM_URL:          sw01035922000msuni0902.fits
SUN_POSTN:       346.60d {+23h 06m 24s}   -5.74d {-05d 44' 08"}
SUN_DIST:         47.56 [deg]   Sun_angle= 1.8 [hr] (West of Sun)
MOON_POSTN:      250.57d {+16h 42m 17s}  -21.86d {-21d 51' 41"}
MOON_DIST:        86.77 [deg]
MOON_ILLUM:      53 [%]
GAL_COORDS:       80.92,-10.45 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      337.38, 47.07 [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 #29596
V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov, D. Cheryasov (Lomonosov Moscow State University, SAI, Physics Department),
R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA),
R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias),
D. Buckley (South African Astronomical Observatory),
O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University)
MASTER-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the Swift GRB 210305A ( A. D'Ai et al., GCN 29595) errorbox 17580 sec after notice time and 17602 sec after trigger time at 2021-03-05 23:56:26 UT, with upper limit up to 16.9 mag. The observations began at zenith distance = 82 deg. The sun altitude is -39.6 deg.
The galactic latitude b = -11 deg., longitude l = 81 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1561780
We obtain a following upper limits.
```
Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

   17632 |   MASTER-Kislovodsk |   C |    60 | 16.9 |        
   17713 |   MASTER-Kislovodsk |   C |    60 | 16.9 |        
```
Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
GCN Circular #29611
H. A. Krimm (NSF), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), A. D'Ai (INAF-IASFPA), S. Laha (GSFC/UMBC), 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-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 210305A (trigger #1035922) (D'Ai, et al., GCN Circ. 29595). The BAT ground-calculated position is RA, Dec = 319.808, 34.548 deg which is
```
    RA(J2000)  =  21h 19m 13.9s
    Dec(J2000) = +34d 32' 52.8"
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 74%.
The BAT light curve showed a complex structure with a duration of about ~100 sec. T90 (15-350 keV) is 68.6 +- 4.4 sec (estimated error including systematics).
The time-averaged spectrum from T-21.65 to T+71.76 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.93 +- 0.19, and Epeak of 104.1 +- 19.7 keV (chi squared 43.93 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 7.1 +- 0.2 x 10^-6 erg/cm2 and the 1-sec peak flux measured from T+0.26 sec in the 15-150 keV band is 3.4 +- 0.3 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.49 +- 0.04 (chi squared 71.71 for 57 d.o.f.). 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/1035922/BA/
GCN Circular #29615
A. Belles (PSU) and A. D'Ai (INAF-IASFPA) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 210305A 85 s after the BAT trigger (D'Ai et al., GCN Circ. 29595). No optical afterglow consistent with the XRT position (D'Ai et al. GCN Circ. 29595) 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            86          235          147         >20.19
u_FC               298          548          245         >19.54
white              577         1721          264         >20.51
v                  627         1771          134         >18.55
b                  553         1696          116         >19.37
u                  700         1672           97         >18.86
w1                 676         1818          134         >18.70
m2                 651         1795          136         >18.63
w2                 603         1746          136         >18.60
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.155 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #29625
M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti (PSU), D.N. Burrows (PSU), J. D. Gropp (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester) and A. D'Ai (INAF-IASFPA) report on behalf of the Swift-XRT team:
We have analysed 11 ks of XRT data for GRB 210305A (D'Ai et al. GCN Circ. 29595), from 67 s to 178.1 ks after the BAT trigger. The data comprise 184 s in Windowed Timing (WT) mode (the first 9 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. Using 2502 s of PC mode data and 4 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 319.81054, +34.55403 which is equivalent to:
```
RA (J2000): 21h 19m 14.53s
Dec(J2000): +34d 33' 14.5"
```
with an uncertainty of 1.4 arcsec (radius, 90% confidence).
The late-time light curve (from T0+5.3 ks) can be modelled with a power-law decay with a decay index of alpha=0.91 (+0.10, -0.09).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.44 (+/-0.08). The best-fitting absorption column is 3.2 (+0.5, -0.4) x 10^21 cm^-2, in excess of the Galactic value of 2.0 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.84 (+/-0.16) and a best-fitting absorption column of 4.0 (+0.9, -0.8) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.3 x 10^-11 (6.1 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     4.0 (+0.9, -0.8) x 10^21 cm^-2
Galactic foreground: 2.0 x 10^21 cm^-2
Excess significance: 4.1 sigma
Photon index:	     1.84 (+/-0.16)
```
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01035922.
This circular is an official product of the Swift-XRT team.
GCN Circular #29628
P. Veres, B. Hristov and C. Meegan (all UAH) report on behalf of the Fermi GBM Team:
"At 19:02:59.40 UT on 05 March 2021, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 210305A (trigger 636663784 / 210305794), which was also detected by the Swift/BAT/XRT (D'Ai et al., GCN 29595). The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 90 degrees.
The GBM light curve shows multiple overlapping pulses with a duration (T90) of about 61.7 s (50-300 keV). The time-averaged spectrum from T0-11.3 s to T0+59.4 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.17 +/- 0.09 and the cutoff energy, parameterized as Epeak, is 98 +/- 3 keV.
A Band function fits the spectrum equally well with Epeak= 95 +/- 4 keV, alpha = -0.11 +/- 0.11 and beta = -3.25 +/- 0.45.
The event fluence (10-1000 keV) in this time interval is (9.4 +/- 0.2)E-6 erg/cm^2. The 1-sec peak photon flux measured starting from T0+6.3 s in the 10-1000 keV band is 4.6 +/- 0.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html
For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"
GCN Circular #29641
A. Ridnaia, S. Golenetskii, D. Frederiks, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, report:
The long-duration GRB 210305A (Swift-BAT detection: D'Ai et al., GCN 29595, Krimm et al., GCN 29611; Fermi-GBM observation: Veres et al., GCN 29628) triggered Konus-Wind at T0=68578.330 s UT (19:02:58.330).
The burst light curve shows a multipeaked structure which starts at ~T0-20 s and has the total duration of ~78 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/GRB210305_T68578/
As observed by Konus-Wind, the burst had a fluence of 1.63(-0.31,+0.43)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+4.224 s, of 1.23(-0.51,+0.51)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+57.600 s) is best fit in the 20 keV - 1 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.33(-0.65,+1.71), the high energy photon index beta = -2.45(-0.73,+0.30), the peak energy Ep = 84(-26,+25) keV (chi2 = 75/49 dof).
The spectrum near the peak count rate (measured from T0+0.256 to T0+8.448 s) is best fit in the 20 keV - 1 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.54(-0.32,+0.37) and Ep = 133(-16,+21) keV (chi2 = 44/50 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.3 (chi2 = 42/49 dof).
All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.

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Jochen Greiner, last update: 10-Mar-2021 [Disclaimer]