Gamma-ray Burst 210930A

(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:     Thu 30 Sep 21 02:48:06 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     1075565,   Seg_Num: 0
GRB_RA:          197.435d {+13h 09m 44s} (J2000),
                 197.673d {+13h 10m 41s} (current),
                 196.888d {+13h 07m 33s} (1950)
GRB_DEC:         +48.623d {+48d 37' 22"} (J2000),
                 +48.507d {+48d 30' 27"} (current),
                 +48.889d {+48d 53' 20"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       0 [cnts]    Image_Peak=1197 [image_cnts]
TRIGGER_DUR:     64.000 [sec] 
TRIGGER_INDEX:   20000     E_range: 15-50 keV
BKG_INTEN:       0 [cnts]
BKG_TIME:        0.00 SOD {00:00:00.00} UT
BKG_DUR:         0 [sec]
GRB_DATE:        19487 TJD;   273 DOY;   21/09/30
GRB_TIME:        10012.18 SOD {02:46:52.18} UT
GRB_PHI:         -159.38 [deg]
GRB_THETA:        19.03 [deg]
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    7.50 [sigma]
MERIT_PARAMS:     +1  +0  +0  +6  +1  -2  +0  +0 -61  +0 
SUN_POSTN:       186.59d {+12h 26m 21s}   -2.85d {-02d 50' 46"}
SUN_DIST:         52.25 [deg]   Sun_angle= -0.7 [hr] (East of Sun)
MOON_POSTN:      110.64d {+07h 22m 33s}  +25.79d {+25d 47' 22"}
MOON_DIST:        69.10 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      114.76, 68.21 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      169.51, 50.11 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is an image trigger.  (The RATE_SIGNIF & BKG_{INTEN, TIME, DUR} are undefined.)  
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 = 82.97,7.91 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 30 Sep 21 02:49:18 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     1075565,   Seg_Num: 0
POINT_RA:        197.429d {+13h 09m 43s} (J2000)
POINT_DEC:       +48.644d {+48d 38' 37"} (J2000)
IMG_START_DATE:  19487 TJD;   273 DOY;   21/09/30
IMG_START_TIME:  10152.30 SOD {02:49:12.30} UT,   140.1 [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:     Thu 30 Sep 21 02:51:05 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     1075565,   Seg_Num: 0
GRB_RA:          197.435d {+13h 09m 44s} (J2000),
                 197.673d {+13h 10m 41s} (current),
                 196.888d {+13h 07m 33s} (1950)
GRB_DEC:         +48.623d {+48d 37' 22"} (J2000),
                 +48.507d {+48d 30' 27"} (current),
                 +48.889d {+48d 53' 20"} (1950)
GRB_DATE:        19487 TJD;   273 DOY;   21/09/30
GRB_TIME:        10012.18 SOD {02:46:52.18} UT
TRIGGER_INDEX:   20000
GRB_PHI:         -159.38 [deg]
GRB_THETA:        19.03 [deg]
DELTA_TIME:      0.00 [sec]
TRIGGER_DUR:     64.000 [sec] 
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    7.50 [sigma]
LC_URL:          sw01075565000msb.lc
SUN_POSTN:       186.59d {+12h 26m 21s}   -2.85d {-02d 50' 49"}
SUN_DIST:         52.25 [deg]   Sun_angle= -0.7 [hr] (East of Sun)
MOON_POSTN:      110.67d {+07h 22m 40s}  +25.79d {+25d 47' 15"}
MOON_DIST:        69.08 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      114.76, 68.21 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      169.51, 50.11 [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 an image 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 = 82.97,7.91 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 30 Sep 21 02:53:00 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1075565,   Seg_Num: 0
POINT_RA:        197.429d {+13h 09m 43s} (J2000)
POINT_DEC:       +48.643d {+48d 38' 36"} (J2000)
POINT_ROLL:      193.719d
IMG_START_DATE:  19487 TJD;   273 DOY;   21/09/30
IMG_START_TIME:  10155.81 SOD {02:49:15.81} UT,   143.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.165
N_STARS:         17
X_OFFSET:        561 [pixels]
Y_OFFSET:        425 [pixels]
X_MAX:           1520 [pixels]
Y_MAX:           1384 [pixels]
DET_THRESH:      19
PHOTO_THRESH:    11
SL_URL:          sw01075565000msufc0143.fits
SUN_POSTN:       186.59d {+12h 26m 22s}   -2.85d {-02d 50' 51"}
SUN_DIST:         52.27 [deg]   Sun_angle= -0.7 [hr] (East of Sun)
MOON_POSTN:      110.68d {+07h 22m 44s}  +25.79d {+25d 47' 10"}
MOON_DIST:        69.06 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      114.78, 68.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      169.49, 50.12 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 30 Sep 21 02:53:16 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1075565,   Seg_Num: 0
POINT_RA:        197.429d {+13h 09m 43s} (J2000)
POINT_DEC:       +48.643d {+48d 38' 36"} (J2000)
POINT_ROLL:      193.719d
IMG_START_DATE:  19487 TJD;   273 DOY;   21/09/30
IMG_START_TIME:  10155.81 SOD {02:49:15.81} UT,   143.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.165
N_STARS:         17
X_OFFSET:        561 [pixels]
Y_OFFSET:        425 [pixels]
X_MAX:           1520 [pixels]
Y_MAX:           1384 [pixels]
DET_THRESH:      19
PHOTO_THRESH:    11
SL_URL:          sw01075565000msufc0143.fits
SUN_POSTN:       186.59d {+12h 26m 22s}   -2.85d {-02d 50' 51"}
SUN_DIST:         52.27 [deg]   Sun_angle= -0.7 [hr] (East of Sun)
MOON_POSTN:      110.69d {+07h 22m 45s}  +25.79d {+25d 47' 09"}
MOON_DIST:        69.06 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      114.78, 68.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      169.49, 50.12 [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:     Thu 30 Sep 21 02:54:27 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1075565,   Seg_Num: 0
POINT_RA:        197.429d {+13h 09m 43s} (J2000)
POINT_DEC:       +48.643d {+48d 38' 36"} (J2000)
ROLL:            193.719d
IMG_START_DATE:  19487 TJD;   273 DOY;   21/09/30
IMG_START_TIME:  10155.81 SOD {02:49:15.81} UT,   143.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     654662983
X_OFFSET:        880 [pixels]
Y_OFFSET:        744 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1040
Y_GRB_POS:       904
BINNING_INDEX:   1
IM_URL:          sw01075565000msuni0171.fits
SUN_POSTN:       186.59d {+12h 26m 22s}   -2.85d {-02d 50' 52"}
SUN_DIST:         52.27 [deg]   Sun_angle= -0.7 [hr] (East of Sun)
MOON_POSTN:      110.70d {+07h 22m 47s}  +25.79d {+25d 47' 07"}
MOON_DIST:        69.06 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      114.78, 68.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      169.49, 50.12 [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:     Thu 30 Sep 21 02:53:36 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     1075565,   Seg_Num: 0
GRB_RA:          197.4017d {+13h 09m 36.40s} (J2000),
                 197.6390d {+13h 10m 33.36s} (current),
                 196.8547d {+13h 07m 25.13s} (1950)
GRB_DEC:         +48.6284d {+48d 37' 42.2"} (J2000),
                 +48.5130d {+48d 30' 46.6"} (current),
                 +48.8945d {+48d 53' 40.0"} (1950)
GRB_ERROR:       3.9 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  19487 TJD;   273 DOY;   21/09/30
IMG_START_TIME:  10160.00 SOD {02:49:20.00} UT,   147.8 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       186.59d {+12h 26m 22s}   -2.85d {-02d 50' 52"}
SUN_DIST:         52.25 [deg]   Sun_angle= -0.7 [hr] (East of Sun)
MOON_POSTN:      110.69d {+07h 22m 46s}  +25.79d {+25d 47' 09"}
MOON_DIST:        69.05 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      114.82, 68.21 [deg] galactic lon,lat of the burst
ECL_COORDS:      169.48, 50.10 [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:     Thu 30 Sep 21 02:54:32 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1075565,   Seg_Num: 0
POINT_RA:        197.429d {+13h 09m 43s} (J2000)
POINT_DEC:       +48.643d {+48d 38' 36"} (J2000)
ROLL:            193.719d
IMG_START_DATE:  19487 TJD;   273 DOY;   21/09/30
IMG_START_TIME:  10155.81 SOD {02:49:15.81} UT,   143.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     654662983
X_OFFSET:        880 [pixels]
Y_OFFSET:        744 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1040
Y_GRB_POS:       904
BINNING_INDEX:   1
IM_URL:          sw01075565000msuni0171.fits
SUN_POSTN:       186.59d {+12h 26m 22s}   -2.85d {-02d 50' 52"}
SUN_DIST:         52.27 [deg]   Sun_angle= -0.7 [hr] (East of Sun)
MOON_POSTN:      110.70d {+07h 22m 48s}  +25.79d {+25d 47' 06"}
MOON_DIST:        69.05 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      114.78, 68.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      169.49, 50.12 [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 #30897
V. D'Elia (SSDC & INAF-OAR), E. Ambrosi (INAF-IASFPA), S. Laha (GSFC/UMBC/CRESST), A. Y. Lien (U Tampa), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), M. H. Siegel (PSU) and A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift Observatory Team:
At 02:46:52 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 210930A (trigger=1075565). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 197.435, +48.623 which is
```
   RA(J2000) = 13h 09m 44s
   Dec(J2000) = +48d 37' 22"
```
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 15 sec. The peak count rate was ~800 counts/sec (15-350 keV), at ~8 sec after the trigger.
The XRT began observing the field at 02:49:12.3 UT, 140.1 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source located at RA, Dec 197.40185, 48.62853 which is equivalent to:
```
   RA(J2000)  = 13h 09m 36.44s
   Dec(J2000) = +48d 37' 42.7"
```
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This location is 81 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 in excess of the Galactic value (9.55 x 10^19 cm^-2, Willingale et al. 2013), with an excess column of 6.4 (+3.87/-3.20) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 143 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 none of the XRT error circle. 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 0.010.
Burst Advocate for this burst is V. D'Elia (valerio.delia AT ssdc.asi.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:     Thu 30 Sep 21 02:59:58 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1075565,   Seg_Num: 0
POINT_RA:        197.427d {+13h 09m 43s} (J2000)
POINT_DEC:       +48.644d {+48d 38' 38"} (J2000)
POINT_ROLL:      193.715d
IMG_START_DATE:  19487 TJD;   273 DOY;   21/09/30
IMG_START_TIME:  10313.77 SOD {02:51:53.77} UT,   301.6 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.860
N_STARS:         32
X_OFFSET:        321 [pixels]
Y_OFFSET:        185 [pixels]
X_MAX:           1760 [pixels]
Y_MAX:           1624 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw01075565000msufc0301.fits
SUN_POSTN:       186.59d {+12h 26m 23s}   -2.85d {-02d 50' 58"}
SUN_DIST:         52.28 [deg]   Sun_angle= -0.7 [hr] (East of Sun)
MOON_POSTN:      110.75d {+07h 23m 00s}  +25.78d {+25d 46' 53"}
MOON_DIST:        69.02 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      114.79, 68.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      169.48, 50.12 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 30 Sep 21 03:00:07 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1075565,   Seg_Num: 0
POINT_RA:        197.427d {+13h 09m 43s} (J2000)
POINT_DEC:       +48.644d {+48d 38' 38"} (J2000)
POINT_ROLL:      193.715d
IMG_START_DATE:  19487 TJD;   273 DOY;   21/09/30
IMG_START_TIME:  10313.77 SOD {02:51:53.77} UT,   301.6 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.860
N_STARS:         32
X_OFFSET:        321 [pixels]
Y_OFFSET:        185 [pixels]
X_MAX:           1760 [pixels]
Y_MAX:           1624 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    6
SL_URL:          sw01075565000msufc0301.fits
SUN_POSTN:       186.59d {+12h 26m 23s}   -2.85d {-02d 50' 58"}
SUN_DIST:         52.28 [deg]   Sun_angle= -0.7 [hr] (East of Sun)
MOON_POSTN:      110.75d {+07h 23m 00s}  +25.78d {+25d 46' 53"}
MOON_DIST:        69.02 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      114.79, 68.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      169.48, 50.12 [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:     Thu 30 Sep 21 03:01:20 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1075565,   Seg_Num: 0
POINT_RA:        197.427d {+13h 09m 43s} (J2000)
POINT_DEC:       +48.644d {+48d 38' 38"} (J2000)
ROLL:            193.715d
IMG_START_DATE:  19487 TJD;   273 DOY;   21/09/30
IMG_START_TIME:  10313.77 SOD {02:51:53.77} UT,   301.6 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     654663141
X_OFFSET:        880 [pixels]
Y_OFFSET:        744 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1040
Y_GRB_POS:       904
BINNING_INDEX:   1
IM_URL:          sw01075565000msuni0329.fits
SUN_POSTN:       186.60d {+12h 26m 23s}   -2.85d {-02d 51' 00"}
SUN_DIST:         52.28 [deg]   Sun_angle= -0.7 [hr] (East of Sun)
MOON_POSTN:      110.76d {+07h 23m 03s}  +25.78d {+25d 46' 50"}
MOON_DIST:        69.02 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      114.79, 68.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      169.48, 50.12 [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:     Thu 30 Sep 21 03:01:34 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1075565,   Seg_Num: 0
POINT_RA:        197.427d {+13h 09m 43s} (J2000)
POINT_DEC:       +48.644d {+48d 38' 38"} (J2000)
ROLL:            193.715d
IMG_START_DATE:  19487 TJD;   273 DOY;   21/09/30
IMG_START_TIME:  10313.77 SOD {02:51:53.77} UT,   301.6 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     654663141
X_OFFSET:        880 [pixels]
Y_OFFSET:        744 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1040
Y_GRB_POS:       904
BINNING_INDEX:   1
IM_URL:          sw01075565000msuni0329.fits
SUN_POSTN:       186.60d {+12h 26m 23s}   -2.85d {-02d 51' 00"}
SUN_DIST:         52.28 [deg]   Sun_angle= -0.7 [hr] (East of Sun)
MOON_POSTN:      110.76d {+07h 23m 03s}  +25.78d {+25d 46' 49"}
MOON_DIST:        69.01 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      114.79, 68.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      169.48, 50.12 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_image.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 30 Sep 21 03:07:53 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1075565,   Seg_Num: 0
POINT_RA:        197.428d {+13h 09m 43s} (J2000)
POINT_DEC:       +48.644d {+48d 38' 37"} (J2000)
POINT_ROLL:      193.715d
IMG_START_DATE:  19487 TJD;   273 DOY;   21/09/30
IMG_START_TIME:  10891.97 SOD {03:01:31.97} UT,   879.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.279
N_STARS:         45
X_OFFSET:        321 [pixels]
Y_OFFSET:        185 [pixels]
X_MAX:           1760 [pixels]
Y_MAX:           1624 [pixels]
DET_THRESH:      19
PHOTO_THRESH:    11
SL_URL:          sw01075565000msufc0879.fits
SUN_POSTN:       186.60d {+12h 26m 24s}   -2.85d {-02d 51' 05"}
SUN_DIST:         52.28 [deg]   Sun_angle= -0.7 [hr] (East of Sun)
MOON_POSTN:      110.82d {+07h 23m 18s}  +25.78d {+25d 46' 34"}
MOON_DIST:        68.98 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      114.79, 68.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      169.48, 50.12 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Thu 30 Sep 21 03:08:02 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1075565,   Seg_Num: 0
POINT_RA:        197.428d {+13h 09m 43s} (J2000)
POINT_DEC:       +48.644d {+48d 38' 37"} (J2000)
POINT_ROLL:      193.715d
IMG_START_DATE:  19487 TJD;   273 DOY;   21/09/30
IMG_START_TIME:  10891.97 SOD {03:01:31.97} UT,   879.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.279
N_STARS:         45
X_OFFSET:        321 [pixels]
Y_OFFSET:        185 [pixels]
X_MAX:           1760 [pixels]
Y_MAX:           1624 [pixels]
DET_THRESH:      19
PHOTO_THRESH:    11
SL_URL:          sw01075565000msufc0879.fits
SUN_POSTN:       186.60d {+12h 26m 24s}   -2.85d {-02d 51' 06"}
SUN_DIST:         52.28 [deg]   Sun_angle= -0.7 [hr] (East of Sun)
MOON_POSTN:      110.82d {+07h 23m 18s}  +25.78d {+25d 46' 34"}
MOON_DIST:        68.98 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      114.79, 68.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      169.48, 50.12 [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:     Thu 30 Sep 21 03:09:59 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1075565,   Seg_Num: 0
POINT_RA:        197.428d {+13h 09m 43s} (J2000)
POINT_DEC:       +48.644d {+48d 38' 37"} (J2000)
ROLL:            193.715d
IMG_START_DATE:  19487 TJD;   273 DOY;   21/09/30
IMG_START_TIME:  10891.97 SOD {03:01:31.97} UT,   879.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     654663719
X_OFFSET:        880 [pixels]
Y_OFFSET:        744 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1040
Y_GRB_POS:       904
BINNING_INDEX:   1
IM_URL:          sw01075565000msuni0907.fits
SUN_POSTN:       186.60d {+12h 26m 24s}   -2.85d {-02d 51' 07"}
SUN_DIST:         52.28 [deg]   Sun_angle= -0.7 [hr] (East of Sun)
MOON_POSTN:      110.84d {+07h 23m 22s}  +25.77d {+25d 46' 29"}
MOON_DIST:        68.97 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      114.79, 68.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      169.48, 50.12 [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:     Thu 30 Sep 21 03:10:14 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1075565,   Seg_Num: 0
POINT_RA:        197.428d {+13h 09m 43s} (J2000)
POINT_DEC:       +48.644d {+48d 38' 37"} (J2000)
ROLL:            193.715d
IMG_START_DATE:  19487 TJD;   273 DOY;   21/09/30
IMG_START_TIME:  10891.97 SOD {03:01:31.97} UT,   879.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     654663719
X_OFFSET:        880 [pixels]
Y_OFFSET:        744 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1040
Y_GRB_POS:       904
BINNING_INDEX:   1
IM_URL:          sw01075565000msuni0907.fits
SUN_POSTN:       186.60d {+12h 26m 24s}   -2.85d {-02d 51' 08"}
SUN_DIST:         52.28 [deg]   Sun_angle= -0.7 [hr] (East of Sun)
MOON_POSTN:      110.85d {+07h 23m 23s}  +25.77d {+25d 46' 28"}
MOON_DIST:        68.97 [deg]
MOON_ILLUM:      40 [%]
GAL_COORDS:      114.79, 68.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      169.48, 50.12 [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 #30900
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
Using 1714 s of XRT Photon Counting mode data and 2 UVOT images for GRB 210930A, 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 = 197.40188, +48.62856 which is equivalent to:
```
RA (J2000): 13h 09m 36.45s
Dec (J2000): +48d 37' 42.8"
```
with an uncertainty of 2.4 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 #30901
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-Tavrida robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the Swift GRB 210930A ( V. D'Elia et al., GCN 30897) errorbox 48786 sec after notice time and 48953 sec after trigger time at 2021-09-30 16:22:45 UT, with upper limit up to 17.2 mag. Observations started at twilight. The observations began at zenith distance = 59 deg. The sun altitude is -11.0 deg.
The galactic latitude b = 68 deg., longitude l = 114 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1737711
We obtain a following upper limits.
```
Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

   32055 |             MASTER- |   C |     1 | 14.1 |        
   32055 |             MASTER- |   C |     1 | 15.1 |        
   36978 |             MASTER- |   C |   180 | 20.0 |        
   49043 |      MASTER-Tavrida |   C |   180 | 17.2 |        
```
Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
GCN Circular #30902
A. D'Ai (INAF-IASFPA), A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU), D.N. Burrows (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), A. Melandri (INAF-OAB), T. Sbarrato (INAF-OAB) and V. D'Elia report on behalf of the Swift-XRT team:
We have analysed 6.3 ks of XRT data for GRB 210930A (D'Elia et al. GCN Circ. 30897), from 143 s to 52.5 ks after the BAT trigger. The data comprise 63 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN Circ. 30900).
The light curve can be modelled with a power-law decay with a decay index of alpha=0.71 (+0.09, -0.08).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 4.04 (+0.30, -0.27). The best-fitting absorption column is 1.46 (+0.18, -0.16) x 10^22 cm^-2, in excess of the Galactic value of 9.6 x 10^19 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 2.2 (+0.4, -0.3) and a best-fitting absorption column of 6.1 (+2.4, -2.0) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.7 x 10^-11 (7.5 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     6.1 (+2.4, -2.0) x 10^21 cm^-2
Galactic foreground: 9.6 x 10^19 cm^-2
Excess significance: 5.0 sigma
Photon index:	     2.2 (+0.4, -0.3)
```
If the light curve continues to decay with a power-law decay index of 0.71, the count rate at T+24 hours will be 6.7 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.5 x 10^-13 (5.0 x 10^-13) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01075565.
This circular is an official product of the Swift-XRT team.
GCN Circular #30903
A. Belles (PSU) and V. D'Elia (SSDC & INAF-OAR) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 210930A 144 s after the BAT trigger (D'Elia et al., GCN Circ. 30897). No optical afterglow consistent with the XRT position (Osborne et al. GCN Circ. 30900) 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           144          293          147         >19.9
u_FC               302          551          246         >19.6
white              144         1722          411         >20.6
v                  631         1773          136         >18.7
b                  559         1873          134         >19.6
u                  302         1848          363         >19.7
w1                 681         1824          136         >19.5
m2                 655         1450           39         >18.7
w2                 607         1747          117         >20.4
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.010 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #30909
Y.-D. Hu, T.-R. Sun, E. Fernandez-Garcia, A. J. Castro-Tirado, M. D. Caballero-Garcia, R. Sanchez-Ramirez, M. A. Castro Tirado (IAA-CSIC) and I. Vico (CAHA) on behalf of a larger collaboration, report:
Following the detection of GRB 210930A by Swift (V. D'Elia et al. GCNC 30897), we triggered the 2.2m CAHA telescope (+ CAFOS) at the Calar Alto Observatory (Almeria, Spain). Images were gathered after the twilight starting on Sep. 30 18:56:50 UT (i.e. 16.2 hour post trigger) in Sloan-gri bands with 90 s exposure each. On the co-added r-band image (6x90s), no optical transient down to 22.6 mag is detected at the X-ray afterglow candidate position reported by Swift/XRT (V. D'Elia et al. GCNC 30897, J.P. Osborne et al. GCNC 30900). This non-detection is consistent with the report from A. Belles et al. (GCNC 30903) and V. Lipunov et al.(GCNC 30901).
We thank the staff at Calar Alto observatory for their excellent support.
GCN Circular #30917
H. A. Krimm (NSF), S. D. Barthelmy (GSFC), V. D'Elia (SSDC & INAF-OAR), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU), M. Stamatikos (OSU) (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 210930A (trigger #1075565) (D'Elia et al., GCN Circ. 30897). The BAT ground-calculated position is RA, Dec = 197.415, 48.630 deg which is
```
   RA(J2000)  =  13h 09m 39.5s
   Dec(J2000) = +48d 37' 47.1"
```
with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%.
The mask-weighted light curve shows a single-pulse structure that starts at ~T+6 s, peaks at ~T+9 s, and ends at ~T+20 s. T90 (15-350 keV) is 11.81 +- 1.94 sec (estimated error including systematics).
The time-averaged spectrum from T+5.84 to T+19.24 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.58 +- 0.19. The fluence in the 15-150 keV band is 4.0 +- 0.5 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+8.40 sec in the 15-150 keV band is 0.7 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/1075565/BA/

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Jochen Greiner, last update: 01-Oct-2021 [Disclaimer]