Gamma-ray Burst 210730A

(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:     Fri 30 Jul 21 04:57:50 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     1062150,   Seg_Num: 0
GRB_RA:          149.592d {+09h 58m 22s} (J2000),
                 150.032d {+10h 00m 08s} (current),
                 148.563d {+09h 54m 15s} (1950)
GRB_DEC:         +69.705d {+69d 42' 19"} (J2000),
                 +69.601d {+69d 36' 05"} (current),
                 +69.944d {+69d 56' 39"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       4918 [cnts]    Image_Peak=612 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   148     E_range: 25-100 keV
BKG_INTEN:       14834 [cnts]
BKG_TIME:        17836.54 SOD {04:57:16.54} UT
BKG_DUR:         8 [sec]
GRB_DATE:        19425 TJD;   211 DOY;   21/07/30
GRB_TIME:        17849.21 SOD {04:57:29.21} UT
GRB_PHI:         -55.36 [deg]
GRB_THETA:        30.06 [deg]
SOLN_STATUS:     0x20010103
RATE_SIGNIF:     68.62 [sigma]
IMAGE_SIGNIF:    18.82 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  +6  +0  +0 -60  +0 
SUN_POSTN:       129.67d {+08h 38m 42s}  +18.45d {+18d 27' 05"}
SUN_DIST:         52.65 [deg]   Sun_angle= -1.4 [hr] (East of Sun)
MOON_POSTN:       22.16d {+01h 28m 38s}   +5.29d {+05d 17' 32"}
MOON_DIST:        97.27 [deg]
MOON_ILLUM:      63 [%]
GAL_COORDS:      141.21, 40.73 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      119.25, 52.25 [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 position matches one of the nearby galaxy sources in the on-board catalog!  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This matches a source in the ground catalog: NGC3034,   delta=0.217 [deg].  
COMMENTS:        This is a GRB in nearby galaxy or it is noise.  
COMMENTS:        This trigger occurred at longitude,latitude = 192.20,5.47 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(0.0<100sec) coincident with the FERMI_GBM event (trignum=649313854).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 30 Jul 21 04:57:53 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      44
TRIGGER_NUM:     649313854
GRB_RA:          142.883d {+09h 31m 32s} (J2000),
                 143.333d {+09h 33m 20s} (current),
                 141.832d {+09h 27m 20s} (1950)
GRB_DEC:         +67.417d {+67d 25' 00"} (J2000),
                 +67.321d {+67d 19' 14"} (current),
                 +67.637d {+67d 38' 14"} (1950)
GRB_ERROR:       4.62 [deg radius, statistical plus systematic]
GRB_INTEN:       730 [cnts/sec]
DATA_SIGNIF:     31.80 [sigma]
INTEG_TIME:      1.024 [sec]
GRB_DATE:        19425 TJD;   211 DOY;   21/07/30
GRB_TIME:        17849.03 SOD {04:57:29.03} UT
GRB_PHI:           0.00 [deg]
GRB_THETA:        35.00 [deg]
DATA_TIME_SCALE: 1.0240 [sec]
HARD_RATIO:      0.65
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      53%  Distant Particles
2nd_MOST_LIKELY:  45%  GRB
DETECTORS:       1,0,0, 1,0,0, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:       129.67d {+08h 38m 42s}  +18.45d {+18d 27' 05"}
SUN_DIST:         49.65 [deg]   Sun_angle= -0.9 [hr] (East of Sun)
MOON_POSTN:       22.16d {+01h 28m 38s}   +5.29d {+05d 17' 33"}
MOON_DIST:        96.53 [deg]
MOON_ILLUM:      63 [%]
GAL_COORDS:      145.46, 39.85 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      117.84, 49.02 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210730207/quicklook/glg_lc_medres34_bn210730207.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 265.52,25.43 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(0.0<100sec) coincident with the SWIFT_BAT event (trignum=1062150).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 30 Jul 21 04:58:11 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      58
TRIGGER_NUM:     649313854
GRB_RA:          143.670d {+09h 34m 41s} (J2000),
                 144.125d {+09h 36m 30s} (current),
                 142.606d {+09h 30m 25s} (1950)
GRB_DEC:         +68.380d {+68d 22' 48"} (J2000),
                 +68.283d {+68d 16' 59"} (current),
                 +68.603d {+68d 36' 10"} (1950)
GRB_ERROR:       3.20 [deg radius, statistical only]
DATA_SIGNIF:     34.20 [sigma]
DATA_INTERVAL:   1.024 [sec]
GRB_DATE:        19425 TJD;   211 DOY;   21/07/30
GRB_TIME:        17849.03 SOD {04:57:29.03} UT
GRB_PHI:           0.00 [deg]
GRB_THETA:        34.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4173 (Gnd S/W Version number)
SUN_POSTN:       129.67d {+08h 38m 42s}  +18.45d {+18d 27' 04"}
SUN_DIST:         50.66 [deg]   Sun_angle= -1.0 [hr] (East of Sun)
MOON_POSTN:       22.16d {+01h 28m 38s}   +5.29d {+05d 17' 36"}
MOON_DIST:        96.28 [deg]
MOON_ILLUM:      63 [%]
GAL_COORDS:      144.17, 39.66 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      117.51, 50.01 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210730207/quicklook/glg_lc_medres34_bn210730207.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_649313854.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.  
COMMENTS:        The POS_MAP_URL file will not be created/available until ~1.5 min after the notice.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(0.0<100sec) coincident with the SWIFT_BAT event (trignum=1062150).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 30 Jul 21 04:58:39 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      0
TRIGGER_NUM:     649313854
GRB_RA:          144.530d {+09h 38m 07s} (J2000),
                 144.990d {+09h 39m 58s} (current),
                 143.453d {+09h 33m 49s} (1950)
GRB_DEC:         +69.330d {+69d 19' 48"} (J2000),
                 +69.232d {+69d 13' 55"} (current),
                 +69.555d {+69d 33' 19"} (1950)
GRB_ERROR:       2.79 [deg radius, statistical only]
DATA_SIGNIF:     29.80 [sigma]
DATA_INTERVAL:   2.048 [sec]
GRB_DATE:        19425 TJD;   211 DOY;   21/07/30
GRB_TIME:        17849.03 SOD {04:57:29.03} UT
GRB_PHI:           0.00 [deg]
GRB_THETA:        33.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       129.67d {+08h 38m 42s}  +18.45d {+18d 27' 04"}
SUN_DIST:         51.66 [deg]   Sun_angle= -1.0 [hr] (East of Sun)
MOON_POSTN:       22.16d {+01h 28m 39s}   +5.30d {+05d 17' 42"}
MOON_DIST:        96.03 [deg]
MOON_ILLUM:      63 [%]
GAL_COORDS:      142.90, 39.46 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      117.17, 50.98 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210730207/quicklook/glg_lc_medres34_bn210730207.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_649313854.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
COMMENTS:        This is likely a Long GRB.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.  
COMMENTS:        The POS_MAP_URL file will not be created/available until ~1.5 min after the notice.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(0.0<100sec) coincident with the SWIFT_BAT event (trignum=1062150).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 30 Jul 21 05:06:55 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     649313854
GRB_RA:          141.230d {+09h 24m 55s} (J2000),
                 141.748d {+09h 27m 00s} (current),
                 140.014d {+09h 20m 03s} (1950)
GRB_DEC:         +72.840d {+72d 50' 24"} (J2000),
                 +72.746d {+72d 44' 46"} (current),
                 +73.055d {+73d 03' 19"} (1950)
GRB_ERROR:       3.59 [deg radius, statistical only]
GRB_DATE:        19425 TJD;   211 DOY;   21/07/30
GRB_TIME:        17849.03 SOD {04:57:29.03} UT
GRB_PHI:         356.00 [deg]
GRB_THETA:        30.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       129.68d {+08h 38m 43s}  +18.45d {+18d 26' 59"}
SUN_DIST:         54.73 [deg]   Sun_angle= -0.8 [hr] (East of Sun)
MOON_POSTN:       22.23d {+01h 28m 54s}   +5.32d {+05d 19' 29"}
MOON_DIST:        93.26 [deg]
MOON_ILLUM:      63 [%]
GAL_COORDS:      139.72, 36.78 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      112.71, 53.43 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210730207/quicklook/glg_lc_medres34_bn210730207.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210730207/quicklook/glg_locplot_all_bn210730207.png
COMMENTS:        Fermi-GBM Final Position.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file should be available by the time this FINAL notice is produced.  
COMMENTS:        This notice was generated completely by automated pipeline processing.  
COMMENTS:        In the LAT Field-of-view.  
COMMENTS:        This is likely a Long GRB.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(0.0<100sec) coincident with the SWIFT_BAT event (trignum=1062150).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 30 Jul 21 05:15:10 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     1062150,   Seg_Num: 0
GRB_RA:          149.5967d {+09h 58m 23.20s} (J2000),
                 150.0359d {+10h 00m 08.61s} (current),
                 148.5672d {+09h 54m 16.13s} (1950)
GRB_DEC:         +69.6911d {+69d 41' 27.9"} (J2000),
                 +69.5873d {+69d 35' 14.1"} (current),
                 +69.9300d {+69d 55' 47.8"} (1950)
GRB_ERROR:       6.0 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       6.73e-10 [erg/cm2/sec]
GRB_SIGNIF:      5.65 [sigma]
IMG_START_DATE:  19425 TJD;   211 DOY;   21/07/30
IMG_START_TIME:  17930.83 SOD {04:58:50.83} UT,   81.6 [sec] since BAT Trigger Time
TAM[0-3]:        327.64 237.19 261.69 243.53
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       129.69d {+08h 38m 45s}  +18.45d {+18d 26' 54"}
SUN_DIST:         52.64 [deg]   Sun_angle= -1.4 [hr] (East of Sun)
MOON_POSTN:       22.29d {+01h 29m 10s}   +5.35d {+05d 21' 16"}
MOON_DIST:        97.19 [deg]
MOON_ILLUM:      63 [%]
GAL_COORDS:      141.23, 40.74 [deg] galactic lon,lat of the burst
ECL_COORDS:      119.26, 52.24 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This matches a source in the BAT ground catalog: NGC3034,   delta=0.218 [deg].  
COMMENTS:        The XRT position is 0.84 arcmin from the BAT position.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 30 Jul 21 05:15:20 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     1062150,   Seg_Num: 0
GRB_RA:          149.5967d {+09h 58m 23.2s} (J2000),
                 150.0359d {+10h 00m 08.6s} (current),
                 148.5672d {+09h 54m 16.1s} (1950)
GRB_DEC:         +69.6911d {+69d 41' 27.9"} (J2000),
                 +69.5873d {+69d 35' 14.1"} (current),
                 +69.9300d {+69d 55' 47.8"} (1950)
GRB_ERROR:       5.8 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       32 [cnts]
IMG_START_DATE:  19425 TJD;   211 DOY;   21/07/30
IMG_START_TIME:  17930.83 SOD {04:58:50.83} UT,   81.6 [sec] since BAT Trigger Time
CENTROID_X:      286.01,  raw= 286  [pixels]
CENTROID_Y:      311.94,  raw= 312  [pixels]
ROLL:            203.97 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   32.63
GRB_POS_XRT_Z:   -50.40
IMAGE_URL:       sw01062150000msxps_rw.img
SUN_POSTN:       129.69d {+08h 38m 45s}  +18.45d {+18d 26' 54"}
SUN_DIST:         52.64 [deg]   Sun_angle= -1.4 [hr] (East of Sun)
MOON_POSTN:       22.29d {+01h 29m 10s}   +5.36d {+05d 21' 18"}
MOON_DIST:        97.19 [deg]
MOON_ILLUM:      63 [%]
GAL_COORDS:      141.23, 40.74 [deg] galactic lon,lat of the burst
ECL_COORDS:      119.26, 52.24 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 30 Jul 21 05:15:30 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     1062150,   Seg_Num: 0
GRB_RA:          149.5967d {+09h 58m 23.2s} (J2000),
                 150.0359d {+10h 00m 08.6s} (current),
                 148.5672d {+09h 54m 16.1s} (1950)
GRB_DEC:         +69.6911d {+69d 41' 27.9"} (J2000),
                 +69.5873d {+69d 35' 14.1"} (current),
                 +69.9300d {+69d 55' 47.8"} (1950)
GRB_ERROR:       5.8 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       32 [cnts]
IMG_START_DATE:  19425 TJD;   211 DOY;   21/07/30
IMG_START_TIME:  17930.83 SOD {04:58:50.83} UT,   81.6 [sec] since BAT Trigger Time
CENTROID_X:      286.01,  raw= 286  [pixels]
CENTROID_Y:      311.94,  raw= 312  [pixels]
ROLL:            203.97 [deg]
GAIN:            1
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   32.63
GRB_POS_XRT_Z:   -50.40
IMAGE_URL:       sw01062150000msxps_rw.img
SUN_POSTN:       129.69d {+08h 38m 45s}  +18.45d {+18d 26' 54"}
SUN_DIST:         52.64 [deg]   Sun_angle= -1.4 [hr] (East of Sun)
MOON_POSTN:       22.29d {+01h 29m 10s}   +5.36d {+05d 21' 20"}
MOON_DIST:        97.19 [deg]
MOON_ILLUM:      63 [%]
GAL_COORDS:      141.23, 40.74 [deg] galactic lon,lat of the burst
ECL_COORDS:      119.26, 52.24 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 30 Jul 21 05:16:12 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1062150,   Seg_Num: 0
POINT_RA:        149.588d {+09h 58m 21s} (J2000)
POINT_DEC:       +69.707d {+69d 42' 26"} (J2000)
ROLL:            203.972d
IMG_START_DATE:  19425 TJD;   211 DOY;   21/07/30
IMG_START_TIME:  17939.61 SOD {04:58:59.61} UT,   90.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     649313967
X_OFFSET:        866 [pixels]
Y_OFFSET:        772 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1026
Y_GRB_POS:       932
BINNING_INDEX:   1
IM_URL:          sw01062150000msuni0118.fits
SUN_POSTN:       129.69d {+08h 38m 45s}  +18.45d {+18d 26' 53"}
SUN_DIST:         52.66 [deg]   Sun_angle= -1.4 [hr] (East of Sun)
MOON_POSTN:       22.30d {+01h 29m 11s}   +5.36d {+05d 21' 30"}
MOON_DIST:        97.17 [deg]
MOON_ILLUM:      63 [%]
GAL_COORDS:      141.21, 40.72 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      119.25, 52.25 [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 30 Jul 21 05:16:27 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1062150,   Seg_Num: 0
POINT_RA:        149.588d {+09h 58m 21s} (J2000)
POINT_DEC:       +69.707d {+69d 42' 26"} (J2000)
ROLL:            203.972d
IMG_START_DATE:  19425 TJD;   211 DOY;   21/07/30
IMG_START_TIME:  17939.61 SOD {04:58:59.61} UT,   90.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     649313967
X_OFFSET:        866 [pixels]
Y_OFFSET:        772 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1026
Y_GRB_POS:       932
BINNING_INDEX:   1
IM_URL:          sw01062150000msuni0118.fits
SUN_POSTN:       129.69d {+08h 38m 45s}  +18.45d {+18d 26' 53"}
SUN_DIST:         52.66 [deg]   Sun_angle= -1.4 [hr] (East of Sun)
MOON_POSTN:       22.30d {+01h 29m 12s}   +5.36d {+05d 21' 33"}
MOON_DIST:        97.17 [deg]
MOON_ILLUM:      63 [%]
GAL_COORDS:      141.21, 40.72 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      119.25, 52.25 [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:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_image.fits.gz file does not exist; skipping the attachment.

GCN Circular #30548
E. Sonbas (Adiyaman Univ.), S. D. Barthelmy (GSFC), A. D'Ai (INAF-IASFPA), D. M. Palmer (LANL), T. Sakamoto (AGU), B. Sbarufatti (PSU) and M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift Observatory Team:
At 04:57:29 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 210730A (trigger=1062150). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 149.592, +69.705 which is
```
   RA(J2000) = 09h 58m 22s
   Dec(J2000) = +69d 42' 19"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). Although the BAT lightcurve is not immediately available due to telemetry limitations, the trigger information indicates a very bright peak (68 sigma in rates) of at least 1 second duration.
The XRT began observing the field at 04:58:50.8 UT, 81.6 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 149.59149, 69.69227 which is equivalent to:
```
   RA(J2000)  = 09h 58m 21.96s
   Dec(J2000) = +69d 41' 32.2"
```
with an uncertainty of 8.2 arcseconds (radius, 90% containment). This location is 45 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. We cannot determine whether the source is fading at the present time. No spectrum from the promptly downlinked event data is yet available to determine the column density.
The initial flux in the 2.5 s image was 6.73e-10 erg cm^-2 s^-1 (0.2-10 keV).
UVOT took a finding chart exposure of 113 seconds with the White filter starting 90 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image processing FAILED because of no aspect solution. Data from the list of sources generated on-board are not available at this time. No correction has been made for the expected extinction corresponding to E(B-V) of 0.096.
We note that this location is close to the nearby galaxy M82, although well outside the main disk. For this reason, the initial GCN Notice misreported it as a Galactic transient.
Burst Advocate for this burst is E. Sonbas (edasonbas AT yahoo.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:     Fri 30 Jul 21 05:28:42 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     1062150,   Seg_Num: 0
GRB_RA:          149.5914d {+09h 58m 21.93s} (J2000),
                 150.0306d {+10h 00m 07.34s} (current),
                 148.5618d {+09h 54m 14.83s} (1950)
GRB_DEC:         +69.6922d {+69d 41' 31.9"} (J2000),
                 +69.5884d {+69d 35' 18.1"} (current),
                 +69.9310d {+69d 55' 51.7"} (1950)
GRB_ERROR:       8.2 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  19425 TJD;   211 DOY;   21/07/30
IMG_START_TIME:  18010.00 SOD {05:00:10.00} UT,   160.8 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       129.70d {+08h 38m 47s}  +18.45d {+18d 26' 46"}
SUN_DIST:         52.64 [deg]   Sun_angle= -1.4 [hr] (East of Sun)
MOON_POSTN:       22.39d {+01h 29m 35s}   +5.40d {+05d 24' 11"}
MOON_DIST:        97.11 [deg]
MOON_ILLUM:      63 [%]
GAL_COORDS:      141.23, 40.73 [deg] galactic lon,lat of the burst
ECL_COORDS:      119.26, 52.24 [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:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.11% < P(seren) < 0.58%.

GCN Circular #30550
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team.
Using 40 s of XRT Photon Counting mode data and 1 UVOT images for GRB 210730A, 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 = 149.59012, +69.68936 which is equivalent to:
```
RA (J2000): 09h 58m 21.63s
Dec (J2000): +69d 41' 21.7"
```
with an uncertainty of 4.5 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 #30552
N. P. M. Kuin (UCL-MSSL) and E. Sonbas (Adiyaman Univ.) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 210730A 90 s after the BAT trigger (Sonbas et al., GCN Circ. 30548). No optical afterglow consistent with the XRT position (Beardmore et al. GCN Circ. 30550) 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            90          204          112         >17.0
white               90         4145          308         >16.7
v                 4355         4555          197         >15.5
b                 3740         3940          197         >16.4
u                 3535         5146          370         >16.5
w1                4765         4965          197         >18.0
m2                4560         4760          197         >19.7
w2                4151         4351          197         >18.6
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.097 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #30553
J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A. Melandri (INAF-OAB), T. Sbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB) and E. Sonbas report on behalf of the Swift-XRT team:
We have analysed 9.1 ks of XRT data for GRB 210730A (Sonbas et al. GCN Circ. 30548), from 87 s to 33.8 ks after the BAT trigger. The data comprise 71 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN Circ. 30550).
The light curve can be modelled with an initial power-law decay with an index of alpha=6.1 (+1.6, -2.1), followed by a break at T+107 s to an alpha of 1.18 (+/-0.04).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.4 (+/-0.3). The best-fitting absorption column is 6.7 (+2.0, -1.7) x 10^21 cm^-2, in excess of the Galactic value of 6.3 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 3.5 x 10^-11 (8.2 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     6.7 (+2.0, -1.7) x 10^21 cm^-2
Galactic foreground: 6.3 x 10^20 cm^-2
Excess significance: 5.9 sigma
Photon index:	     2.4 (+/-0.3)
```
If the light curve continues to decay with a power-law decay index of 1.18, the count rate at T+24 hours will be 3.1 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x 10^-13 (2.5 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/01062150.
This circular is an official product of the Swift-XRT team.
GCN Circular #30554
T. Sakamoto (AGU), S. D. Barthelmy (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), E. Sonbas (Adiyaman Univ.), M. Stamatikos (OSU), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
Using the data set from T-240 to T+200 sec from the recent telemetry downlink, we report further analysis of BAT GRB 210730A (trigger #1062150) (Sonbas et al., GCN Circ. 30548). The BAT ground-calculated position is RA, Dec = 149.570, 69.703 deg which is
```
   RA(J2000)  =  09h 58m 16.8s
   Dec(J2000) = +69d 42' 12.4"
```
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 55%.
The mask-weighted light curve shows a single-peaked structure that starts at ~T-0.5, peaks at ~T+0.5, and ends at ~T+5. T90 (15-350 keV) is 3.86 +- 0.66 sec (estimated error including systematics).
The time-averaged spectrum from T-0.32 to T+5.01 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.41 +- 0.11. The fluence in the 15-150 keV band is 1.3 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+0.17 sec in the 15-150 keV band is 7.1 +- 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/1062150/BA/
GCN Circular #30555
V. Prasad (IUCAA), P. Sawant (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:
Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al, 2020, arxiv:2011.07067) showed the detection of a long GRB 210730A, which was also detected by Swift-BAT (Sonbas et al., GCN 30548, Sakamoto et al., GCN 30554) and Swift-XRT (Beardmore et al., GCN 30550).
The source was clearly detected in the 20-200 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2021-07-30 04:57:28.55 UT. The measured peak count rate associated with the burst is 502 (+181, -71) cts/s above the background in the combined data of four quadrants, with a total of 621 (+161, -206) cts. The local mean background count rate was 508 (+12, -11) cts/s. Using cumulative rates, we measure a T90 of 3.3 (+1.1, -1.9) s.
It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.
CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb [1]. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.
```
Links:
------
[1] http://astrosat.iucaa.in/czti/?q=grb
```
GCN Circular #30557
J. Wood (NASA/MSFC) reports on behalf of the Fermi GBM Team:
"At 04:57:29.03 UT on 30 July 2021, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 210730A (trigger 649313854 / 210730207) which was also detected by the Swift/BAT and Swift/XRT (E. Sonbas et al. 2021, GCN 30548).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 32 degrees.
The GBM light curve consists of a single peak with a duration (T90) of about 5 s (50-300 keV). The time-averaged spectrum from T0 to T0+6 s is well fit by a power law function with an exponential high-energy cutoff. The power law index is -0.68 +/- 0.07 and the cutoff energy, parameterized as Epeak, is 170 +/- 11 keV
The event fluence (10-1000 keV) in this time interval is (2.9 +/- 0.1)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+0.3 s in the 10-1000 keV band is 10.5 +/- 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 #30560
P. D'Avanzo (INAF-OAB), V. D'Elia (ASI-SSDC), M. Della Valle (INAF-OACN) A. Melandri (INAF-OAB), A. Rossi (INAF-OAS), G. Tagliaferri (INAF-OOAB), A. Harutyunyan, D. Carosati (INAF-TNG) on behalf of the CIBO collaboration report:
We observed the field of GRB 210730A (Sonbas et al., GCN Circ. 30548; Prasad et al., GCN Circ. 30555; Wood et al., GCN Circ. 30577) with the Italian 3.6m TNG telescope equipped with the optical camera DOLORES. A series of images were obtained with the r-sdss filter on 2021-07-30 from 21:41:57 UT to 22:08:38 UT (i.e. about 17 hours after the burst).
At the edge of the XRT error circle (https://www.swift.ac.uk/xrt_positions/01062150/) we detect a faint optical source at the following position (J2000):
```
RA: 09:58:21.96
Dec: +69:41:23.6
(+/- 1.0"). 
```
With preliminary photometry, carried out using a small aperture to minimise contamination from a nearby bright star, we derive the following magnitude: r = 22.7 +/- 0.2
(AB; calibrated against the SDSS catalogue). In our co-added image we reach a limiting magnitude of r ~ 23.5 (AB, 3sigma c.l.).
We note that the same source is visible in archival Pan-STARRS images. Using a common set of reference stars and carrying out differential photometry on TNG and Pan-STARRS images we find no evidence for a change in magnitude of this source.
Therefore, this source is likely not related to GRB 210730A. Alternatively, it can be the GRB host galaxy.

GCN Circular #30562
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 210730A ( E. Sonbas et al., GCN 30548) errorbox 47961 sec after notice time and 47903 sec after trigger time at 2021-07-30 18:17:14 UT, with upper limit up to 19.2 mag. Observations started at twilight. The observations began at zenith distance = 54 deg. The sun altitude is -11.0 deg.
MASTER-IAC robotic telescope located in Spain (IAC Teide Observatory) was pointed to the Swift GRB 210730A errorbox 64883 sec after notice time and 64826 sec after trigger time at 2021-07-30 22:59:17 UT, with upper limit up to 17.7 mag. The observations began at zenith distance = 76 deg. The sun altitude is -34.0 deg.
MASTER-Kislovodsk robotic telescope located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the Swift GRB 210730A errorbox 71489 sec after notice time and 71432 sec after trigger time at 2021-07-31 00:49:22 UT, with upper limit up to 16.5 mag. Observations started at twilight. The observations began at zenith distance = 65 deg. The sun altitude is -11.7 deg.
The galactic latitude b = 41 deg., longitude l = 141 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1675497
We obtain a following upper limits.

Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

   47934 |      MASTER-Tavrida |   C |    60 | 17.0 |        
   48488 |      MASTER-Tavrida |   C |    60 | 17.9 |        
   48962 |      MASTER-Tavrida |   C |    60 | 18.4 |        
   49437 |      MASTER-Tavrida |   C |    60 | 18.8 |        
   49912 |      MASTER-Tavrida |   C |    60 | 18.7 |        
   50386 |      MASTER-Tavrida |   C |    60 | 19.1 |        
   50684 |      MASTER-Tavrida |   C |   180 | 18.9 |        
   51671 |      MASTER-Tavrida |   C |   180 | 19.2 |        
   64916 |          MASTER-IAC |   C |   180 | 17.5 |        
   64916 |          MASTER-IAC |   C |   180 | 17.3 |        
   65096 |          MASTER-IAC |   C |   540 | 17.7 |  Coadd 
   65131 |          MASTER-IAC |   C |   180 | 17.2 |        
   65131 |          MASTER-IAC |   C |   180 | 16.8 |        
   65311 |          MASTER-IAC |   C |   540 | 17.5 |  Coadd 
   65341 |          MASTER-IAC |   C |   180 | 17.2 |        
   65341 |          MASTER-IAC |   C |   180 | 17.0 |        
   65551 |          MASTER-IAC |   C |   180 | 17.1 |        
   65551 |          MASTER-IAC |   C |   180 | 16.8 |        
   65760 |          MASTER-IAC |   C |   180 | 17.0 |        
   65970 |          MASTER-IAC |   C |   180 | 17.2 |        
   65970 |          MASTER-IAC |   C |   180 | 16.7 |        
   66179 |          MASTER-IAC |   C |   180 | 17.0 |        
   66179 |          MASTER-IAC |   C |   180 | 16.9 |        
   66394 |          MASTER-IAC |   C |   180 | 17.1 |        
   66394 |          MASTER-IAC |   C |   180 | 16.8 |        
   66604 |          MASTER-IAC |   C |   180 | 17.0 |        
   66604 |          MASTER-IAC |   C |   180 | 16.8 |        
   66815 |          MASTER-IAC |   C |   180 | 17.1 |        
   66815 |          MASTER-IAC |   C |   180 | 16.6 |        
   67023 |          MASTER-IAC |   C |   180 | 17.0 |        
   67023 |          MASTER-IAC |   C |   180 | 16.7 |        
   67238 |          MASTER-IAC |   C |   180 | 17.0 |        
   67238 |          MASTER-IAC |   C |   180 | 16.7 |        
   67565 |          MASTER-IAC |   C |    60 | 16.7 |        
   67834 |          MASTER-IAC |   C |    60 | 16.7 |        
   67834 |          MASTER-IAC |   C |    60 | 16.2 |        
   67923 |          MASTER-IAC |   C |    60 | 16.0 |        
   68440 |          MASTER-IAC |   C |   180 | 16.9 |        
   68440 |          MASTER-IAC |   C |   180 | 16.6 |        
   68770 |          MASTER-IAC |   C |    60 | 16.4 |        
   69041 |          MASTER-IAC |   C |    60 | 16.5 |        
   69041 |          MASTER-IAC |   C |    60 | 16.0 |        
   69130 |          MASTER-IAC |   C |    60 | 15.7 |        
   69636 |          MASTER-IAC |   C |   180 | 16.6 |        
   69636 |          MASTER-IAC |   C |   180 | 16.3 |        
   69964 |          MASTER-IAC |   C |    60 | 16.2 |        
   70235 |          MASTER-IAC |   C |    60 | 16.4 |        
   70235 |          MASTER-IAC |   C |    60 | 15.8 |        
   70323 |          MASTER-IAC |   C |    60 | 15.5 |        
   70835 |          MASTER-IAC |   C |   180 | 16.4 |        
   70835 |          MASTER-IAC |   C |   180 | 15.9 |        
   71522 |   MASTER-Kislovodsk |   C |   180 | 16.5 |        
   71722 |   MASTER-Kislovodsk |   C |   180 | 16.1 |        
   72000 |          MASTER-IAC |   C |   180 | 16.1 |        
   72000 |          MASTER-IAC |   C |   180 | 16.0 |        
   73190 |          MASTER-IAC |   C |   180 | 15.8 |        
   73190 |          MASTER-IAC |   C |   180 | 15.9 |

Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.

GCN Circular #30563
Y.-D. Hu, T.-R. Sun, I. Carrasco, E. Fernandez-Garcia, A. J. Castro-Tirado and M. D. Caballero-Garcia (IAA-CSIC), D. Hiriart and W. H. Lee (UNAM), I. H. Park (SKKU), S. Gongora and I. Vico (CAHA) on behalf of a larger collaboration, report:
The 60cm BOOTES-5/JGT robotic telescope at Observatorio Astronomico Nacional in San Pedro Martir (Mexico) automatically followed up GRB 210730A (Sonbas et al., GCNC 30548) starting at 05:56:36 UT (~1 hr after trigger). Within the Swift/XRT error position (Beardmore et al., GCNC 30550), no new optical afterglow is found down to 20.9 mag in the co-added images (clear filter, 20x60 s).
We also triggered 2.2m CAHA telescope (+ CAFOS) at the Calar Alto Observatory (Almeria, Spain) to follow up this event. A series of gri-bands images were gathered starting on July 30, 20:25 UT (i.e. 15.5 h post trigger). On the co-added image (r-band, 15 x 60s), no new optical object is detected down to 23.0 mag at the X-ray afterglow position reported by Swift/XRT (Beardmore et al., GCNC 30550), consistent with the TNG non-detection (D'Avanzo et al., GCNC 30560).
We thank the staff at San Pedro Martir and Calar Alto Observtories for their excellent support.
GCN Circular #30564
F. De Luise, F. Onori (INAF-OAAb), R. Carini, S Piranomonte (INAF-OAR), A. Melandri (INAF-OAB), M. Canzari, M. Dolci, G. Valentini, A. Di Cianno, A. Valentini, N. Napoleone, P. Tedesco (INAF-OAAb), E. Brocato (INAF-OAAb and OAR) on behalf of the GRAWITA collaboration report:
On 2021-07-30 we observed the field of GRB210730A (Sonbas et al., GCN Circ. 30548; Prasad et al., GCN Circ. 30555; Wood et al., GCN Circ. 30577) with the 0.9m Schmidt Telescope of the INAF - Astronomical Observatory of Abruzzo located at 2150 meters a.s.l. at Campo Imperatore (Italy) and equipped with a 4096x4096 CCD, covering a field of view of 1.15�1.15 square degrees.
A series of optical images of the field have been obtained with the r-Sloan and z-Sloan filters on 2021-07-30. The observation started at 19:50:29 UT (about 15 hr after the burst) for a total exposure time of 26x180s in r band and 15x180s in z band, respectively. A preliminary analysis does not show any optical counterpart candidate within the XRT error circle (https://www.swift.ac.uk/xrt_positions/01062150/ ).
GCN Circular #30629
S. Schmidl, A. Nicuesa Guelbenzu, S. Klose, S. Melnikov, B. Stecklum, C. Hoegner (all Tautenburg) and J. Greiner (MPE Garching) report:
We observed the field of GRB 210730A (Sonbas et al., GCN 30548) with the Tautenburg 1.34m Schmidt telescope equipped with the TAUKAM 6kx6k CCD camera.
Observations started at 20:38 UT on July 30, about 15 hours after the GRB trigger. Consistent with the non-detection of an afterglow candidate by D'Avanzo et al. (GCN 30560) and Hu et al. (GCN 30563), we do not detect any new source inside the XRT error circle (Beardmore et al., GCN 30550). Calibrated against SDSS stars in the field, for any transient we provide an upper limit of r(AB) > 21.8 mag.

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