Gamma-ray Burst 240730A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 30 Jul 24 07:53:21 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     1245636,   Seg_Num: 0
GRB_RA:           37.829d {+02h 31m 19s} (J2000),
                  38.285d {+02h 33m 08s} (current),
                  36.908d {+02h 27m 38s} (1950)
GRB_DEC:         +59.074d {+59d 04' 27"} (J2000),
                 +59.182d {+59d 10' 55"} (current),
                 +58.853d {+58d 51' 10"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       0 [cnts]    Image_Peak=1494 [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:        20521 TJD;   212 DOY;   24/07/30
GRB_TIME:        28326.09 SOD {07:52:06.09} UT
GRB_PHI:         -99.78 [deg]
GRB_THETA:         8.92 [deg]
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    7.74 [sigma]
MERIT_PARAMS:     +1  +0  +0  +6  +1  -2  +0  +1 -24  +0 
SUN_POSTN:       130.06d {+08h 40m 15s}  +18.35d {+18d 21' 15"}
SUN_DIST:         75.21 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:       63.12d {+04h 12m 28s}  +25.51d {+25d 30' 46"}
MOON_DIST:        37.86 [deg]
MOON_ILLUM:      26 [%]
GAL_COORDS:      135.47, -1.35 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       57.22, 41.43 [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 = 306.85,12.91 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 30 Jul 24 07:54:22 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     1245636,   Seg_Num: 0
POINT_RA:         37.826d {+02h 31m 18s} (J2000)
POINT_DEC:       +59.072d {+59d 04' 21"} (J2000)
IMG_START_DATE:  20521 TJD;   212 DOY;   24/07/30
IMG_START_TIME:  28454.81 SOD {07:54:14.81} UT,   128.7 [sec] since BAT Trigger
Time
COUNTS:          34    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        4    Max_iter_allowed= 4
ERROR_CODE:      2
COMMENTS:        SWIFT-XRT Nack Position.  
COMMENTS:        Algorithm did not converge; too many iterations.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 30 Jul 24 07:56:03 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     1245636,   Seg_Num: 0
GRB_RA:           37.829d {+02h 31m 19s} (J2000),
                  38.285d {+02h 33m 08s} (current),
                  36.908d {+02h 27m 38s} (1950)
GRB_DEC:         +59.074d {+59d 04' 27"} (J2000),
                 +59.182d {+59d 10' 55"} (current),
                 +58.853d {+58d 51' 10"} (1950)
GRB_DATE:        20521 TJD;   212 DOY;   24/07/30
GRB_TIME:        28326.09 SOD {07:52:06.09} UT
TRIGGER_INDEX:   20000
GRB_PHI:         -99.78 [deg]
GRB_THETA:         8.92 [deg]
DELTA_TIME:      0.00 [sec]
TRIGGER_DUR:     64.000 [sec] 
SOLN_STATUS:     0x13
RATE_SIGNIF:     0.00 [sigma]
IMAGE_SIGNIF:    7.74 [sigma]
LC_URL:          sw01245636000msb.lc
SUN_POSTN:       130.06d {+08h 40m 15s}  +18.35d {+18d 21' 13"}
SUN_DIST:         75.21 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:       63.14d {+04h 12m 34s}  +25.52d {+25d 31' 07"}
MOON_DIST:        37.86 [deg]
MOON_ILLUM:      26 [%]
GAL_COORDS:      135.47, -1.35 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       57.22, 41.43 [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 = 306.85,12.91 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 30 Jul 24 07:57:14 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1245636,   Seg_Num: 0
POINT_RA:         37.825d {+02h 31m 18s} (J2000)
POINT_DEC:       +59.072d {+59d 04' 20"} (J2000)
POINT_ROLL:      78.440d
IMG_START_DATE:  20521 TJD;   212 DOY;   24/07/30
IMG_START_TIME:  28459.34 SOD {07:54:19.34} UT,   133.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.719
N_STARS:         184
X_OFFSET:        491 [pixels]
Y_OFFSET:        538 [pixels]
X_MAX:           1450 [pixels]
Y_MAX:           1497 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw01245636000msufc0133.fits
SUN_POSTN:       130.06d {+08h 40m 15s}  +18.35d {+18d 21' 13"}
SUN_DIST:         75.21 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:       63.16d {+04h 12m 37s}  +25.52d {+25d 31' 16"}
MOON_DIST:        37.86 [deg]
MOON_ILLUM:      26 [%]
GAL_COORDS:      135.46, -1.35 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       57.22, 41.43 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 30 Jul 24 07:57:27 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1245636,   Seg_Num: 0
POINT_RA:         37.825d {+02h 31m 18s} (J2000)
POINT_DEC:       +59.072d {+59d 04' 20"} (J2000)
POINT_ROLL:      78.440d
IMG_START_DATE:  20521 TJD;   212 DOY;   24/07/30
IMG_START_TIME:  28459.34 SOD {07:54:19.34} UT,   133.2 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.719
N_STARS:         184
X_OFFSET:        491 [pixels]
Y_OFFSET:        538 [pixels]
X_MAX:           1450 [pixels]
Y_MAX:           1497 [pixels]
DET_THRESH:      14
PHOTO_THRESH:    7
SL_URL:          sw01245636000msufc0133.fits
SUN_POSTN:       130.06d {+08h 40m 15s}  +18.35d {+18d 21' 13"}
SUN_DIST:         75.21 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:       63.16d {+04h 12m 38s}  +25.52d {+25d 31' 18"}
MOON_DIST:        37.87 [deg]
MOON_ILLUM:      26 [%]
GAL_COORDS:      135.46, -1.35 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       57.22, 41.43 [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:     Tue 30 Jul 24 07:58:50 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1245636,   Seg_Num: 0
POINT_RA:         37.825d {+02h 31m 18s} (J2000)
POINT_DEC:       +59.072d {+59d 04' 20"} (J2000)
ROLL:            78.440d
IMG_START_DATE:  20521 TJD;   212 DOY;   24/07/30
IMG_START_TIME:  28459.34 SOD {07:54:19.34} UT,   133.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     744018893
X_OFFSET:        810 [pixels]
Y_OFFSET:        857 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       970
Y_GRB_POS:       1017
BINNING_INDEX:   1
IM_URL:          sw01245636000msuni0167.fits
SUN_POSTN:       130.06d {+08h 40m 16s}  +18.35d {+18d 21' 12"}
SUN_DIST:         75.21 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:       63.17d {+04h 12m 41s}  +25.52d {+25d 31' 28"}
MOON_DIST:        37.87 [deg]
MOON_ILLUM:      26 [%]
GAL_COORDS:      135.46, -1.35 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       57.22, 41.43 [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:     Tue 30 Jul 24 07:59:05 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1245636,   Seg_Num: 0
POINT_RA:         37.825d {+02h 31m 18s} (J2000)
POINT_DEC:       +59.072d {+59d 04' 20"} (J2000)
ROLL:            78.440d
IMG_START_DATE:  20521 TJD;   212 DOY;   24/07/30
IMG_START_TIME:  28459.34 SOD {07:54:19.34} UT,   133.2 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     744018893
X_OFFSET:        810 [pixels]
Y_OFFSET:        857 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       970
Y_GRB_POS:       1017
BINNING_INDEX:   1
IM_URL:          sw01245636000msuni0167.fits
SUN_POSTN:       130.06d {+08h 40m 16s}  +18.35d {+18d 21' 12"}
SUN_DIST:         75.21 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:       63.17d {+04h 12m 42s}  +25.53d {+25d 31' 30"}
MOON_DIST:        37.87 [deg]
MOON_ILLUM:      26 [%]
GAL_COORDS:      135.46, -1.35 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       57.22, 41.43 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 30 Jul 24 08:05:22 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1245636,   Seg_Num: 0
POINT_RA:         37.824d {+02h 31m 18s} (J2000)
POINT_DEC:       +59.072d {+59d 04' 21"} (J2000)
POINT_ROLL:      78.439d
IMG_START_DATE:  20521 TJD;   212 DOY;   24/07/30
IMG_START_TIME:  28617.38 SOD {07:56:57.38} UT,   291.3 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.893
N_STARS:         190
X_OFFSET:        251 [pixels]
Y_OFFSET:        298 [pixels]
X_MAX:           1690 [pixels]
Y_MAX:           1737 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    4
SL_URL:          sw01245636000msufc0291.fits
SUN_POSTN:       130.07d {+08h 40m 17s}  +18.35d {+18d 21' 08"}
SUN_DIST:         75.21 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:       63.24d {+04h 12m 57s}  +25.54d {+25d 32' 18"}
MOON_DIST:        37.88 [deg]
MOON_ILLUM:      26 [%]
GAL_COORDS:      135.46, -1.35 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       57.22, 41.43 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 30 Jul 24 08:05:43 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1245636,   Seg_Num: 0
POINT_RA:         37.824d {+02h 31m 18s} (J2000)
POINT_DEC:       +59.072d {+59d 04' 21"} (J2000)
POINT_ROLL:      78.439d
IMG_START_DATE:  20521 TJD;   212 DOY;   24/07/30
IMG_START_TIME:  28617.38 SOD {07:56:57.38} UT,   291.3 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.893
N_STARS:         190
X_OFFSET:        251 [pixels]
Y_OFFSET:        298 [pixels]
X_MAX:           1690 [pixels]
Y_MAX:           1737 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    4
SL_URL:          sw01245636000msufc0291.fits
SUN_POSTN:       130.07d {+08h 40m 17s}  +18.35d {+18d 21' 07"}
SUN_DIST:         75.21 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:       63.24d {+04h 12m 58s}  +25.54d {+25d 32' 21"}
MOON_DIST:        37.88 [deg]
MOON_ILLUM:      26 [%]
GAL_COORDS:      135.46, -1.35 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       57.22, 41.43 [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:     Tue 30 Jul 24 08:06:45 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1245636,   Seg_Num: 0
POINT_RA:         37.824d {+02h 31m 18s} (J2000)
POINT_DEC:       +59.072d {+59d 04' 21"} (J2000)
ROLL:            78.439d
IMG_START_DATE:  20521 TJD;   212 DOY;   24/07/30
IMG_START_TIME:  28617.38 SOD {07:56:57.38} UT,   291.3 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     744019051
X_OFFSET:        810 [pixels]
Y_OFFSET:        857 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       970
Y_GRB_POS:       1017
BINNING_INDEX:   1
IM_URL:          sw01245636000msuni0325.fits
SUN_POSTN:       130.07d {+08h 40m 17s}  +18.35d {+18d 21' 07"}
SUN_DIST:         75.21 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:       63.25d {+04h 13m 00s}  +25.54d {+25d 32' 29"}
MOON_DIST:        37.88 [deg]
MOON_ILLUM:      26 [%]
GAL_COORDS:      135.46, -1.35 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       57.22, 41.43 [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:     Tue 30 Jul 24 08:06:58 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1245636,   Seg_Num: 0
POINT_RA:         37.824d {+02h 31m 18s} (J2000)
POINT_DEC:       +59.072d {+59d 04' 21"} (J2000)
ROLL:            78.439d
IMG_START_DATE:  20521 TJD;   212 DOY;   24/07/30
IMG_START_TIME:  28617.38 SOD {07:56:57.38} UT,   291.3 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     744019051
X_OFFSET:        810 [pixels]
Y_OFFSET:        857 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       970
Y_GRB_POS:       1017
BINNING_INDEX:   1
IM_URL:          sw01245636000msuni0325.fits
SUN_POSTN:       130.07d {+08h 40m 17s}  +18.35d {+18d 21' 07"}
SUN_DIST:         75.21 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:       63.25d {+04h 13m 01s}  +25.54d {+25d 32' 31"}
MOON_DIST:        37.88 [deg]
MOON_ILLUM:      26 [%]
GAL_COORDS:      135.46, -1.35 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       57.22, 41.43 [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 #36976
S. B. Cenko (GSFC), P. A. Evans (U Leicester), R. A. J. Eyles-Ferris (U Leicester), K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift Observatory Team:
At 07:52:06 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 240730A (trigger=1245636). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 37.829, +59.074 which is
```
   RA(J2000) = 02h 31m 19s
   Dec(J2000) = +59d 04' 27"
```
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 80 sec. The peak count rate was ~300 counts/sec (15-350 keV), at ~30 sec after the trigger.
The XRT began observing the field at 07:54:14.8 UT, 128.7 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source with an enhanced position: RA, Dec 37.83844, 59.02878 which is equivalent to:
```
   RA(J2000)  = 02h 31m 21.22s
   Dec(J2000) = +59d 01' 43.6"
```
with an uncertainty of 1.9 arcseconds (radius, 90% containment). This location is 163 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at https://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 7.80 x 10^21 cm^-2 (Willingale et al. 2013).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 133 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 coverage of the XRT error circle by the 8'x8' region for the list of sources generated on-board is uncertain because the large number of sources filled the available telemetry. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain, extinction expected.
Although this appears to be a long GRB, its long duration and its position near the Galactic plane (lat=-1.35) raise the possibility that this is a Galactic transient instead. If that is the case then we give it the name Swift J0231.3+5902 .
Burst Advocate for this burst is S. B. Cenko (brad.cenko AT nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/)

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 30 Jul 24 08:11:59 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1245636,   Seg_Num: 0
POINT_RA:         37.824d {+02h 31m 18s} (J2000)
POINT_DEC:       +59.072d {+59d 04' 21"} (J2000)
POINT_ROLL:      78.439d
IMG_START_DATE:  20521 TJD;   212 DOY;   24/07/30
IMG_START_TIME:  29202.65 SOD {08:06:42.65} UT,   876.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.509
N_STARS:         190
X_OFFSET:        251 [pixels]
Y_OFFSET:        298 [pixels]
X_MAX:           1690 [pixels]
Y_MAX:           1737 [pixels]
DET_THRESH:      20
PHOTO_THRESH:    12
SL_URL:          sw01245636000msufc0876.fits
SUN_POSTN:       130.07d {+08h 40m 18s}  +18.35d {+18d 21' 04"}
SUN_DIST:         75.22 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:       63.30d {+04h 13m 13s}  +25.55d {+25d 33' 09"}
MOON_DIST:        37.88 [deg]
MOON_ILLUM:      26 [%]
GAL_COORDS:      135.46, -1.35 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       57.22, 41.43 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 30 Jul 24 08:12:09 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1245636,   Seg_Num: 0
POINT_RA:         37.824d {+02h 31m 18s} (J2000)
POINT_DEC:       +59.072d {+59d 04' 21"} (J2000)
POINT_ROLL:      78.439d
IMG_START_DATE:  20521 TJD;   212 DOY;   24/07/30
IMG_START_TIME:  29202.65 SOD {08:06:42.65} UT,   876.6 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        5.509
N_STARS:         190
X_OFFSET:        251 [pixels]
Y_OFFSET:        298 [pixels]
X_MAX:           1690 [pixels]
Y_MAX:           1737 [pixels]
DET_THRESH:      20
PHOTO_THRESH:    12
SL_URL:          sw01245636000msufc0876.fits
SUN_POSTN:       130.07d {+08h 40m 18s}  +18.35d {+18d 21' 04"}
SUN_DIST:         75.22 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:       63.31d {+04h 13m 13s}  +25.55d {+25d 33' 11"}
MOON_DIST:        37.88 [deg]
MOON_ILLUM:      26 [%]
GAL_COORDS:      135.46, -1.35 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       57.22, 41.43 [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:     Tue 30 Jul 24 08:14:11 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1245636,   Seg_Num: 0
POINT_RA:         37.824d {+02h 31m 18s} (J2000)
POINT_DEC:       +59.072d {+59d 04' 21"} (J2000)
ROLL:            78.439d
IMG_START_DATE:  20521 TJD;   212 DOY;   24/07/30
IMG_START_TIME:  29202.65 SOD {08:06:42.65} UT,   876.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     744019636
X_OFFSET:        810 [pixels]
Y_OFFSET:        857 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       970
Y_GRB_POS:       1017
BINNING_INDEX:   1
IM_URL:          sw01245636000msuni0910.fits
SUN_POSTN:       130.08d {+08h 40m 18s}  +18.35d {+18d 21' 02"}
SUN_DIST:         75.22 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:       63.33d {+04h 13m 18s}  +25.56d {+25d 33' 26"}
MOON_DIST:        37.89 [deg]
MOON_ILLUM:      26 [%]
GAL_COORDS:      135.46, -1.35 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       57.22, 41.43 [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:     Tue 30 Jul 24 08:14:24 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1245636,   Seg_Num: 0
POINT_RA:         37.824d {+02h 31m 18s} (J2000)
POINT_DEC:       +59.072d {+59d 04' 21"} (J2000)
ROLL:            78.439d
IMG_START_DATE:  20521 TJD;   212 DOY;   24/07/30
IMG_START_TIME:  29202.65 SOD {08:06:42.65} UT,   876.6 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     744019636
X_OFFSET:        810 [pixels]
Y_OFFSET:        857 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       970
Y_GRB_POS:       1017
BINNING_INDEX:   1
IM_URL:          sw01245636000msuni0910.fits
SUN_POSTN:       130.08d {+08h 40m 18s}  +18.35d {+18d 21' 02"}
SUN_DIST:         75.22 [deg]   Sun_angle= 6.1 [hr] (West of Sun)
MOON_POSTN:       63.33d {+04h 13m 19s}  +25.56d {+25d 33' 28"}
MOON_DIST:        37.89 [deg]
MOON_ILLUM:      26 [%]
GAL_COORDS:      135.46, -1.35 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       57.22, 41.43 [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 #36977
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team.
Using 915 s of XRT Photon Counting mode data and 2 UVOT images for GRB 240730A, 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 = 37.83822, +59.02875 which is equivalent to:
```
RA (J2000): 02h 31m 21.17s
Dec (J2000): +59d 01' 43.5"
```
with an uncertainty of 2.6 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 #36978
Paul Kuin (MSSL/UCL), R. Caputo and S. B. Cenko (GSFC) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 240730A 133 s after the BAT trigger (Cenko et al., GCN Circ. 36976). No optical afterglow consistent with the XRT position in Evans et al., GCN Circ. 36977, 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           133          283          147         >19.1
u_FC               291          541          246         >19.2
white              133         1026          295         >19.1
u                  291          541          246         >19.2
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 1.146 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #36980
WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on behalf of the KAIT GRB team:
The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at
Lick Observatory, responded to Swift GRB 240730A (Cenko et al.,
GCN 36976) starting at 10:24UT, ~2.53 hours after the burst. A
total of 50x60s images were obtained in the clear (roughly R)
filters. We do not detect any optical afterglow candidate within
the enhanced XRT position error circle (Evans et al., GCN 36977),
neither in single image, nor in the co-add images. The typical
limiting magnitude of our single clear image is about 19.5 mag
calibrated to the PS1 catalog.
GCN Circular #36982
S. Dichiara (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), M. Ferro (INAF-OAB), R. Brivio (INAF-OAB), A. D'Ai (INAF-IASFPA), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto) and P.A. Evans report on behalf of the Swift-XRT team:
We have analysed 7.2 ks of XRT data for GRB 240730A, from 113 s to 23.5 ks after the BAT trigger. The data comprise 14 s in Windowed Timing (WT) mode (the first 9 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode.
The light curve can be modelled with a power-law decay with a decay index of alpha=2.04 (+/-0.24).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.6 (+/-0.4). The best-fitting absorption column is 1.4 (+0.6, -0.5) x 10^22 cm^-2, in excess of the Galactic value of 7.8 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 6.8 x 10^-11 (1.0 x 10^-10) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     1.4 (+0.6, -0.5) x 10^22 cm^-2
Galactic foreground: 7.8 x 10^21 cm^-2
Excess significance: 2.1 sigma
Photon index:	     1.6 (+/-0.4)
```
If the light curve continues to decay with a power-law decay index of 2.04, the count rate at T+24 hours will be 5.4 x 10^-6 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.6 x 10^-16 (5.7 x 10^-16) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01245636.
This circular is an official product of the Swift-XRT team.

GCN Circular #36983
V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik, D. Vlasenko, G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij (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. Gress, N.M. Budnev, O.Ershova (Irkutsk State University, API),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
V. Yurkov, A. Gabovich (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 240730A ( S. B. Cenko et al., GCN 36976) errorbox 37782 sec after notice time and 37859 sec after trigger time at 2024-07-30 18:23:05 UT, with upper limit up to 16.8 mag. Observations started at twilight. The observations began at zenith distance = 71 deg. The sun altitude is -11.9 deg.
The galactic latitude b = -1 deg., longitude l = 136 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2545484
We obtain a following upper limits.

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

   32544 |             MASTER- |   C |    30 | 18.9 |        
   32585 |             MASTER- |   C |    30 | 18.8 |        
   32627 |             MASTER- |   C |    30 | 18.8 |        
   32671 |             MASTER- |   C |    30 | 18.8 |        
   32719 |             MASTER- |   C |    30 | 18.6 |        
   32762 |             MASTER- |   C |    30 | 19.0 |        
   33359 |             MASTER- |   C |    30 | 18.8 |        
   33403 |             MASTER- |   C |    30 | 18.9 |        
   34542 |             MASTER- |   C |   180 | 19.4 |        
   34735 |             MASTER- |   C |   180 | 19.5 |        
   34928 |             MASTER- |   C |   180 | 19.4 |        
   35120 |             MASTER- |   C |   180 | 19.3 |        
   35313 |             MASTER- |   C |   180 | 19.4 |        
   35509 |             MASTER- |   C |   180 | 19.1 |        
   35703 |             MASTER- |   C |   180 | 19.3 |        
   35821 |             MASTER- |   C |    30 | 19.1 |        
   35868 |             MASTER- |   C |    30 | 19.1 |        
   35915 |             MASTER- |   C |    30 | 19.1 |        
   35957 |             MASTER- |   C |    30 | 19.1 |        
   36000 |             MASTER- |   C |    30 | 19.1 |        
   36042 |             MASTER- |   C |    30 | 19.1 |        
   36085 |             MASTER- |   C |    30 | 18.9 |        
   36121 |             MASTER- |   C |    30 | 19.1 |        
   36163 |             MASTER- |   C |    30 | 19.1 |        
   36206 |             MASTER- |   C |    30 | 19.1 |        
   36248 |             MASTER- |   C |    30 | 19.1 |        
   36291 |             MASTER- |   C |    30 | 18.8 |        
   36970 |             MASTER- |   C |   180 | 18.9 |        
   37949 |      MASTER-Tavrida |   C |   180 | 16.8 |        
   38248 |             MASTER- |   C |   180 | 19.3 |        
   39462 |             MASTER- |   C |   180 | 19.2 |

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

GCN Circular #36987
S. Guziy, E. Fernandez-Garcia, I. Perez-Garcia, M.D. Caballero-Garcia, R. Sanchez-Ramirez, S.-Y. Wu and A. J. Castro-Tirado (IAA-CSIC, Granada), Y.-D. Hu (INAF-OAB), D. Hiriart and W. H. Lee (UNAM), C. J. Perez del Pulgar (UMA), I. M. Carrasco-Garcia (SMA) and I. H. Park (SKKU), on behalf of a larger collaboration, report:
Following the detection of GRB 240730A by Swift (Cenko et al. GCNC 36976), the BOOTES-5/JGT 0.6m robotic telescope at Observatorio Astronomico Nacional in San Pedro Martir (Mexico) automatically observed the GRB location starting on Jul. 30, 07:53:50 UT (~ 104 s after trigger). No new optical source is detected on the co-added images (57 x 1 s, clear-filter) within the enhanced Swift/XRT error box (Evans et al. GCNC 36977) down to 18.7 mag. which is consistent with reports from UVOT (Kuin et al., GCNC 36978), KAIT (Zheng et al., GCNC 36980) and MASTER (Lipunov et al. GCNC 36983).
We thank the staff at Observatorio Astronomico Nacional in San Pedro Martir for their excellent support.
GCN Circular #36988
Nello Ruocco at Osservatorio Nastro Verde - Sorrento (Naples) - Italy in a large collaboration with: M.G. Dainotti (National Astronomical Observatory of Japan), Y. Niino (Tokyo University, Institute of Astronomy), K. Kalinowski (Aarhus University, Department of Physics and Astronomy), B. De Simone (Universita' degli Studi Di Salerno) report:
We image the field of GRB 240730A (Trigger 1245636 S. B. Cenko (GSFC), P. A. Evans (U Leicester), R. A. J. Eyles-Ferris (U Leicester), K. L. Page (U Leicester) and D. M. Palmer (LANL) GCN Circular 36976) with telescope of Nastro Verde Observatory - Sorrento (Naples), Italy. Member of: AAVSO - American Association of Variable Star Observers. UAI/SSV - Unione Astrofili Italiani/sezione stelle variabili. AstroCampania Associazione
The observations started at 22:08 UT of 2024/07/30, after about 14.20 hours after the GRB trigger, with clear sky, with principal telescope SC 0.35 f/10 with focal reduced + CCD Sbig ST10 XME I took 20 image of 60 sec each. All images are unfiltered, calibrated with masterdark and masterflat,stacked with Tycho Tracker software We have not detected any clearly visible sources, up to 19.5th magnitude with clear skies.
```
Start T0+                End T0+       Rlim
22:08:20 UT             22:32:39 UT     19.5
```
We did not found any optical counterpart in the error box of the XRTcandidate.
Magnitudes were estimated with the Gaia DR2 cat. and are not corrected for galactic dust extinction.
The message may be cited.
GCN Circular #37005
D. Sadaula (GSFC/UMBC), S. D. Barthelmy (GSFC), S. B. Cenko (GSFC), R. Gupta (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), M. J. Moss (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC), T. Sakamoto (AGU) (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 240730A (trigger #1245636) (Cenko, et al., GCN Circ. 36976). The BAT ground-calculated position is RA, Dec = 37.841, 59.045 deg which is
```
   RA(J2000)  =  02h 31m 21.9s 
   Dec(J2000) = +59d 02' 43.5" 
```
with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 98%.
The BAT mask-weighted light curve displays two spectrally soft peaks. The T90 (15-350 keV) is 50.13 +- 7.60 sec (estimated error including systematics).
The time-averaged spectrum from T-6.06 to T+53.43 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.50 +- 0.19. The fluence in the 15-150 keV band is 6.8 +- 0.9 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T+5.80 sec in the 15-150 keV band is 0.4 +- 0.1 ph/cm2/sec. All the quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1245636
The long duration and proximity to the Galactic plane raised the initial possibility that this was a Galactic transient. However, its subsequent behavior, including a lack of later BAT detections, is consistent with a GRB, making the Galactic transient interpretation less likely.

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Jochen Greiner, last update: 01-Aug-2024 [Disclaimer]