Gamma-ray Burst 240805B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 05 Aug 24 14:39:47 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     1246989,   Seg_Num: 0
GRB_RA:          254.239d {+16h 56m 57s} (J2000),
                 254.511d {+16h 58m 03s} (current),
                 253.687d {+16h 54m 45s} (1950)
GRB_DEC:         +18.323d {+18d 19' 24"} (J2000),
                 +18.286d {+18d 17' 11"} (current),
                 +18.400d {+18d 24' 01"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       3136 [cnts]    Image_Peak=156 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   149     E_range: 25-100 keV
BKG_INTEN:       19455 [cnts]
BKG_TIME:        52118.06 SOD {14:28:38.06} UT
BKG_DUR:         8 [sec]
GRB_DATE:        20527 TJD;   218 DOY;   24/08/05
GRB_TIME:        52134.12 SOD {14:28:54.12} UT
GRB_PHI:          30.82 [deg]
GRB_THETA:        19.81 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     10.90 [sigma]
IMAGE_SIGNIF:    7.47 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  -2  +0  +0 +33  +0 
SUN_POSTN:       136.13d {+09h 04m 31s}  +16.72d {+16d 43' 16"}
SUN_DIST:        110.00 [deg]   Sun_angle= -7.9 [hr] (East of Sun)
MOON_POSTN:      149.97d {+09h 59m 53s}  +15.74d {+15d 44' 22"}
MOON_DIST:        98.30 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       37.90, 33.23 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      250.12, 40.68 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This Notice was delayed by more than 60 sec past the end of the trigger integration interval;  
COMMENTS:        probably due to it occurring during a Malindi downlink session. 
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 12.54,-1.02 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 05 Aug 24 14:40:19 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     1246989,   Seg_Num: 0
GRB_RA:          254.2153d {+16h 56m 51.67s} (J2000),
                 254.4868d {+16h 57m 56.83s} (current),
                 253.6635d {+16h 54m 39.25s} (1950)
GRB_DEC:         +18.3175d {+18d 19' 02.9"} (J2000),
                 +18.2806d {+18d 16' 50.0"} (current),
                 +18.3945d {+18d 23' 40.2"} (1950)
GRB_ERROR:       4.8 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       4.43e-09 [erg/cm2/sec]
GRB_SIGNIF:      11.83 [sigma]
IMG_START_DATE:  20527 TJD;   218 DOY;   24/08/05
IMG_START_TIME:  52212.56 SOD {14:30:12.56} UT,   78.4 [sec] since BAT Trigger Time
TAM[0-3]:        327.69 237.16 261.51 243.72
AMPLIFIER:       2
WAVEFORM:        134
SUN_POSTN:       136.13d {+09h 04m 31s}  +16.72d {+16d 43' 15"}
SUN_DIST:        109.98 [deg]   Sun_angle= -7.9 [hr] (East of Sun)
MOON_POSTN:      149.97d {+09h 59m 54s}  +15.74d {+15d 44' 15"}
MOON_DIST:        98.28 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       37.88, 33.25 [deg] galactic lon,lat of the burst
ECL_COORDS:      250.09, 40.67 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        The XRT position is 1.40 arcmin from the BAT position.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 05 Aug 24 14:40:29 UT
NOTICE_TYPE:     Swift-XRT Image
TRIGGER_NUM:     1246989,   Seg_Num: 0
GRB_RA:          254.2153d {+16h 56m 51.6s} (J2000),
                 254.4868d {+16h 57m 56.8s} (current),
                 253.6635d {+16h 54m 39.2s} (1950)
GRB_DEC:         +18.3175d {+18d 19' 02.9"} (J2000),
                 +18.2806d {+18d 16' 50.0"} (current),
                 +18.3945d {+18d 23' 40.2"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       140 [cnts]
IMG_START_DATE:  20527 TJD;   218 DOY;   24/08/05
IMG_START_TIME:  52212.56 SOD {14:30:12.56} UT,   78.4 [sec] since BAT Trigger Time
CENTROID_X:      275.91,  raw= 276  [pixels]
CENTROID_Y:      318.83,  raw= 319  [pixels]
ROLL:            296.17 [deg]
GAIN:            2
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   48.88
GRB_POS_XRT_Z:   -74.21
IMAGE_URL:       sw01246989000msxps_rw.img
SUN_POSTN:       136.13d {+09h 04m 31s}  +16.72d {+16d 43' 15"}
SUN_DIST:        109.98 [deg]   Sun_angle= -7.9 [hr] (East of Sun)
MOON_POSTN:      149.98d {+09h 59m 54s}  +15.74d {+15d 44' 13"}
MOON_DIST:        98.28 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       37.88, 33.25 [deg] galactic lon,lat of the burst
ECL_COORDS:      250.09, 40.67 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Image.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 05 Aug 24 14:40:33 UT
NOTICE_TYPE:     Swift-XRT Processed Image
TRIGGER_NUM:     1246989,   Seg_Num: 0
GRB_RA:          254.2153d {+16h 56m 51.6s} (J2000),
                 254.4868d {+16h 57m 56.8s} (current),
                 253.6635d {+16h 54m 39.2s} (1950)
GRB_DEC:         +18.3175d {+18d 19' 02.9"} (J2000),
                 +18.2806d {+18d 16' 50.0"} (current),
                 +18.3945d {+18d 23' 40.2"} (1950)
GRB_ERROR:       4.7 [arcsec, radius, statistical plus systematic]
GRB_INTEN:       140 [cnts]
IMG_START_DATE:  20527 TJD;   218 DOY;   24/08/05
IMG_START_TIME:  52212.56 SOD {14:30:12.56} UT,   78.4 [sec] since BAT Trigger Time
CENTROID_X:      275.91,  raw= 276  [pixels]
CENTROID_Y:      318.83,  raw= 319  [pixels]
ROLL:            296.17 [deg]
GAIN:            2
MODE:            3, Long Image mode
WAVEFORM:        134
EXPO_TIME:       2.50 [sec]
GRB_POS_XRT_Y:   48.88
GRB_POS_XRT_Z:   -74.21
IMAGE_URL:       sw01246989000msxps_rw.img
SUN_POSTN:       136.13d {+09h 04m 31s}  +16.72d {+16d 43' 15"}
SUN_DIST:        109.98 [deg]   Sun_angle= -7.9 [hr] (East of Sun)
MOON_POSTN:      149.98d {+09h 59m 54s}  +15.74d {+15d 44' 12"}
MOON_DIST:        98.27 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       37.88, 33.25 [deg] galactic lon,lat of the burst
ECL_COORDS:      250.09, 40.67 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Processed Image.  
COMMENTS:        The object found at this position is either a very bright burst or a cosmic ray hit.  
COMMENTS:        Examine the XRT Image to differentiate (CRs are much more compact); see examples at:  
COMMENTS:        http://www.swift.psu.edu/xrt/XRT_Postage_Stamp_Image_Photo_Gallery.htm .

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 05 Aug 24 14:41:21 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1246989,   Seg_Num: 0
POINT_RA:        254.241d {+16h 56m 58s} (J2000)
POINT_DEC:       +18.321d {+18d 19' 15"} (J2000)
POINT_ROLL:      296.174d
IMG_START_DATE:  20527 TJD;   218 DOY;   24/08/05
IMG_START_TIME:  52222.07 SOD {14:30:22.07} UT,   87.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.383
N_STARS:         81
X_OFFSET:        504 [pixels]
Y_OFFSET:        560 [pixels]
X_MAX:           1463 [pixels]
Y_MAX:           1519 [pixels]
DET_THRESH:      15
PHOTO_THRESH:    8
SL_URL:          sw01246989000msufc0087.fits
SUN_POSTN:       136.13d {+09h 04m 31s}  +16.72d {+16d 43' 15"}
SUN_DIST:        110.00 [deg]   Sun_angle= -7.9 [hr] (East of Sun)
MOON_POSTN:      149.98d {+09h 59m 56s}  +15.73d {+15d 44' 02"}
MOON_DIST:        98.29 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       37.90, 33.23 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      250.12, 40.68 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 05 Aug 24 14:41:30 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1246989,   Seg_Num: 0
POINT_RA:        254.241d {+16h 56m 58s} (J2000)
POINT_DEC:       +18.321d {+18d 19' 15"} (J2000)
POINT_ROLL:      296.174d
IMG_START_DATE:  20527 TJD;   218 DOY;   24/08/05
IMG_START_TIME:  52222.07 SOD {14:30:22.07} UT,   87.9 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        3.383
N_STARS:         81
X_OFFSET:        504 [pixels]
Y_OFFSET:        560 [pixels]
X_MAX:           1463 [pixels]
Y_MAX:           1519 [pixels]
DET_THRESH:      15
PHOTO_THRESH:    8
SL_URL:          sw01246989000msufc0087.fits
SUN_POSTN:       136.13d {+09h 04m 31s}  +16.72d {+16d 43' 15"}
SUN_DIST:        110.00 [deg]   Sun_angle= -7.9 [hr] (East of Sun)
MOON_POSTN:      149.98d {+09h 59m 56s}  +15.73d {+15d 44' 01"}
MOON_DIST:        98.29 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       37.90, 33.23 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      250.12, 40.68 [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:     Mon 05 Aug 24 14:41:02 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     1246989,   Seg_Num: 0
GRB_RA:          254.239d {+16h 56m 57s} (J2000),
                 254.511d {+16h 58m 03s} (current),
                 253.687d {+16h 54m 45s} (1950)
GRB_DEC:         +18.323d {+18d 19' 24"} (J2000),
                 +18.286d {+18d 17' 11"} (current),
                 +18.400d {+18d 24' 01"} (1950)
GRB_DATE:        20527 TJD;   218 DOY;   24/08/05
GRB_TIME:        52134.12 SOD {14:28:54.12} UT
TRIGGER_INDEX:   149
GRB_PHI:          30.82 [deg]
GRB_THETA:        19.81 [deg]
DELTA_TIME:      -5.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     10.90 [sigma]
IMAGE_SIGNIF:    7.47 [sigma]
LC_URL:          sw01246989000msb.lc
SUN_POSTN:       136.13d {+09h 04m 31s}  +16.72d {+16d 43' 15"}
SUN_DIST:        110.00 [deg]   Sun_angle= -7.9 [hr] (East of Sun)
MOON_POSTN:      149.98d {+09h 59m 55s}  +15.74d {+15d 44' 06"}
MOON_DIST:        98.29 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       37.90, 33.23 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      250.12, 40.68 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Lightcurve.  
COMMENTS:           
COMMENTS:        The next comments were copied from the BAT_POS Notice:  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 12.54,-1.02 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 05 Aug 24 14:43:00 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1246989,   Seg_Num: 0
POINT_RA:        254.241d {+16h 56m 58s} (J2000)
POINT_DEC:       +18.321d {+18d 19' 15"} (J2000)
ROLL:            296.174d
IMG_START_DATE:  20527 TJD;   218 DOY;   24/08/05
IMG_START_TIME:  52222.07 SOD {14:30:22.07} UT,   87.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     744561056
X_OFFSET:        880 [pixels]
Y_OFFSET:        723 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1040
Y_GRB_POS:       883
BINNING_INDEX:   1
IM_URL:          sw01246989000msuni0121.fits
SUN_POSTN:       136.13d {+09h 04m 32s}  +16.72d {+16d 43' 14"}
SUN_DIST:        110.00 [deg]   Sun_angle= -7.9 [hr] (East of Sun)
MOON_POSTN:      150.00d {+09h 59m 59s}  +15.73d {+15d 43' 42"}
MOON_DIST:        98.28 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       37.90, 33.23 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      250.12, 40.68 [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:     Mon 05 Aug 24 14:43:08 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1246989,   Seg_Num: 0
POINT_RA:        254.241d {+16h 56m 58s} (J2000)
POINT_DEC:       +18.321d {+18d 19' 15"} (J2000)
ROLL:            296.174d
IMG_START_DATE:  20527 TJD;   218 DOY;   24/08/05
IMG_START_TIME:  52222.07 SOD {14:30:22.07} UT,   87.9 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     744561056
X_OFFSET:        880 [pixels]
Y_OFFSET:        723 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1040
Y_GRB_POS:       883
BINNING_INDEX:   1
IM_URL:          sw01246989000msuni0121.fits
SUN_POSTN:       136.13d {+09h 04m 32s}  +16.72d {+16d 43' 13"}
SUN_DIST:        110.00 [deg]   Sun_angle= -7.9 [hr] (East of Sun)
MOON_POSTN:      150.00d {+09h 59m 59s}  +15.73d {+15d 43' 40"}
MOON_DIST:        98.28 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       37.90, 33.23 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      250.12, 40.68 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the XRT Position Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 05 Aug 24 14:46:08 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1246989,   Seg_Num: 0
POINT_RA:        254.241d {+16h 56m 58s} (J2000)
POINT_DEC:       +18.320d {+18d 19' 12"} (J2000)
POINT_ROLL:      296.174d
IMG_START_DATE:  20527 TJD;   218 DOY;   24/08/05
IMG_START_TIME:  52434.96 SOD {14:33:54.96} UT,   300.8 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.634
N_STARS:         75
X_OFFSET:        560 [pixels]
Y_OFFSET:        403 [pixels]
X_MAX:           1519 [pixels]
Y_MAX:           1362 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw01246989000msufc0300.fits
SUN_POSTN:       136.13d {+09h 04m 32s}  +16.72d {+16d 43' 11"}
SUN_DIST:        110.00 [deg]   Sun_angle= -7.9 [hr] (East of Sun)
MOON_POSTN:      150.02d {+10h 00m 05s}  +15.72d {+15d 43' 03"}
MOON_DIST:        98.26 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       37.90, 33.23 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      250.12, 40.68 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 05 Aug 24 14:46:16 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1246989,   Seg_Num: 0
POINT_RA:        254.241d {+16h 56m 58s} (J2000)
POINT_DEC:       +18.320d {+18d 19' 12"} (J2000)
POINT_ROLL:      296.174d
IMG_START_DATE:  20527 TJD;   218 DOY;   24/08/05
IMG_START_TIME:  52434.96 SOD {14:33:54.96} UT,   300.8 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.634
N_STARS:         75
X_OFFSET:        560 [pixels]
Y_OFFSET:        403 [pixels]
X_MAX:           1519 [pixels]
Y_MAX:           1362 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw01246989000msufc0300.fits
SUN_POSTN:       136.13d {+09h 04m 32s}  +16.72d {+16d 43' 11"}
SUN_DIST:        110.00 [deg]   Sun_angle= -7.9 [hr] (East of Sun)
MOON_POSTN:      150.02d {+10h 00m 05s}  +15.72d {+15d 43' 01"}
MOON_DIST:        98.26 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       37.90, 33.23 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      250.12, 40.68 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN Circular #37043
M. A. Williams (PSU), S. Dichiara (PSU), R. Gupta (NASA GSFC), J. A. Kennea (PSU) and D. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift Observatory Team:
At 14:28:54 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 240805B (trigger=1246989). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 254.239, +18.323 which is
```
   RA(J2000) = 16h 56m 57s
   Dec(J2000) = +18d 19' 24"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 70 sec. The peak count rate was ~2800 counts/sec (15-350 keV), at ~16 sec after the trigger.
The XRT began observing the field at 14:30:12.5 UT, 78.4 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 254.2153, 18.3175 which is equivalent to:
```
   RA(J2000)  = 16h 56m 51.67s
   Dec(J2000) = +18d 19' 03.0"
```
with an uncertainty of 4.8 arcseconds (radius, 90% containment). This location is 83 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy.
UVOT took a finding chart exposure of 150 seconds with the White filter starting 87 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.087.
Burst Advocate for this burst is M. A. Williams (mjw6837 AT psu.edu). 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:     Mon 05 Aug 24 14:51:34 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1246989,   Seg_Num: 0
POINT_RA:        254.241d {+16h 56m 58s} (J2000)
POINT_DEC:       +18.320d {+18d 19' 12"} (J2000)
ROLL:            296.175d
IMG_START_DATE:  20527 TJD;   218 DOY;   24/08/05
IMG_START_TIME:  53012.48 SOD {14:43:32.48} UT,   878.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     744561846
X_OFFSET:        879 [pixels]
Y_OFFSET:        722 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1039
Y_GRB_POS:       882
BINNING_INDEX:   1
IM_URL:          sw01246989000msuni0912.fits
SUN_POSTN:       136.14d {+09h 04m 33s}  +16.72d {+16d 43' 08"}
SUN_DIST:        109.99 [deg]   Sun_angle= -7.9 [hr] (East of Sun)
MOON_POSTN:      150.07d {+10h 00m 16s}  +15.70d {+15d 41' 55"}
MOON_DIST:        98.23 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       37.90, 33.23 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      250.12, 40.68 [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:     Mon 05 Aug 24 14:51:46 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1246989,   Seg_Num: 0
POINT_RA:        254.241d {+16h 56m 58s} (J2000)
POINT_DEC:       +18.320d {+18d 19' 12"} (J2000)
ROLL:            296.175d
IMG_START_DATE:  20527 TJD;   218 DOY;   24/08/05
IMG_START_TIME:  53012.48 SOD {14:43:32.48} UT,   878.4 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     744561846
X_OFFSET:        879 [pixels]
Y_OFFSET:        722 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1039
Y_GRB_POS:       882
BINNING_INDEX:   1
IM_URL:          sw01246989000msuni0912.fits
SUN_POSTN:       136.14d {+09h 04m 33s}  +16.72d {+16d 43' 08"}
SUN_DIST:        109.99 [deg]   Sun_angle= -7.9 [hr] (East of Sun)
MOON_POSTN:      150.07d {+10h 00m 16s}  +15.70d {+15d 41' 52"}
MOON_DIST:        98.23 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       37.90, 33.23 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      250.12, 40.68 [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:     Mon 05 Aug 24 14:50:08 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1246989,   Seg_Num: 0
POINT_RA:        254.241d {+16h 56m 58s} (J2000)
POINT_DEC:       +18.320d {+18d 19' 12"} (J2000)
POINT_ROLL:      296.175d
IMG_START_DATE:  20527 TJD;   218 DOY;   24/08/05
IMG_START_TIME:  53012.48 SOD {14:43:32.48} UT,   878.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.692
N_STARS:         190
X_OFFSET:        320 [pixels]
Y_OFFSET:        163 [pixels]
X_MAX:           1759 [pixels]
Y_MAX:           1602 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw01246989000msufc0878.fits
SUN_POSTN:       136.14d {+09h 04m 33s}  +16.72d {+16d 43' 09"}
SUN_DIST:        109.99 [deg]   Sun_angle= -7.9 [hr] (East of Sun)
MOON_POSTN:      150.05d {+10h 00m 13s}  +15.70d {+15d 42' 13"}
MOON_DIST:        98.24 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       37.90, 33.23 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      250.12, 40.68 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Mon 05 Aug 24 14:50:18 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1246989,   Seg_Num: 0
POINT_RA:        254.241d {+16h 56m 58s} (J2000)
POINT_DEC:       +18.320d {+18d 19' 12"} (J2000)
POINT_ROLL:      296.175d
IMG_START_DATE:  20527 TJD;   218 DOY;   24/08/05
IMG_START_TIME:  53012.48 SOD {14:43:32.48} UT,   878.4 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.692
N_STARS:         190
X_OFFSET:        320 [pixels]
Y_OFFSET:        163 [pixels]
X_MAX:           1759 [pixels]
Y_MAX:           1602 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw01246989000msufc0878.fits
SUN_POSTN:       136.14d {+09h 04m 33s}  +16.72d {+16d 43' 09"}
SUN_DIST:        109.99 [deg]   Sun_angle= -7.9 [hr] (East of Sun)
MOON_POSTN:      150.05d {+10h 00m 13s}  +15.70d {+15d 42' 11"}
MOON_DIST:        98.24 [deg]
MOON_ILLUM:      1 [%]
GAL_COORDS:       37.90, 33.23 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      250.12, 40.68 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN Circular #37050
Z.P. Zhu, X. Liu, J. An, S.Y. Fu, S.Q. Jiang, L.B. He, D. Xu (NAOC) report on behalf of a large collaboration:
We observed the field of GRB 240805B detected by Swift/BAT (Williams et al., GCN 37043), using the JinShan 100cm-C telescope (100C) and 50cm-D telescope (50D) located at Altay, Xinjiang, China.The observation started at 14:55:19 UT on 2024-08-05, ~ 0.44 hr after the BAT trigger. A series of exposures were obtained in the Sloan g-, r-, i-, and z- filters.
No uncataloged source is found within or around the XRT error circle (Williams et al., GCN 37043). The obtained upper limits are as follows:
```
Telescope Tmid-T0/hr Filter Exptime Mag(AB)
100C  0.582 r 5x200s >22.0
100C 0.868 i 5x200s >22.2
100C 1.318 z 7x300s >21.5
50D 1.683 g 20x180s >22.0
```
We acknowledge the excellent support from S.W. Luo, M.M. Yang, Z.K. Feng, Q.C. Zhao and L.F. Huo for enabling these observations.
GCN Circular #37051
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 240805B ( M. A. Williams et al., GCN 37043) errorbox 16180 sec after notice time and 16840 sec after trigger time at 2024-08-05 19:09:34 UT, with upper limit up to 17.1 mag. The observations began at zenith distance = 32 deg. The sun altitude is -19.2 deg.
The galactic latitude b = 33 deg., longitude l = 38 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2551783
We obtain a following upper limits.
```
Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

   16931 |      MASTER-Tavrida |   C |   180 | 16.5 |        
   16931 |      MASTER-Tavrida |   C |   180 | 17.1 |        
```
Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
GCN Circular #37052
R. Strausbaugh (Eastern Illinois University), A. Cucchiara (NASA) report on behalf of a larger collaboration:
We observed the Swift GRB 240805B field (Williams et al., GCN 37043) with the LCOGT 1-meter Sinistro instrument at the South African Astronomical Observatory site, on August 5, from 18:01 to 18:34 UT (corresponding to 3.55 to 4.10 hours after the GRB trigger time) with the sdss r and i filters.
We performed a series of 3x300s exposures in each band. We do not detect an uncataloged source within the XRT error region in either band. This result is consistent with other optcal upper limits (Zhu et al., GCN 37050; Lipunov et al., GCN 37051).
The following 5-sigma upper limits are calculated using the PanSTARRS catalog as reference:
```
r > 21.1
i > 20.5
```
These magnitudes are not corrected for galactic extinction.
GCN Circular #37053
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team.
Using 1007 s of XRT Photon Counting mode data and 3 UVOT images for GRB 240805B, 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 = 254.21255, +18.31958 which is equivalent to:
```
RA (J2000): 16h 56m 51.01s
Dec (J2000): +18d 19' 10.5"
```
with an uncertainty of 3.1 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 #37055
A. Moskvitin, D. Oparin, A Vinokurov (SAO RAS), N. Pankov (HSE, IKI) and A. Pozanenko (IKI) report:
We observed the field of the GRB 240805B (Williams et al., GCN 37043) with the BTA 6-meter telescope of SAO RAS equipped with the focal reducer Scorpio-I. We obtained 7 x 120 + 30 sec images on August 5, 2024-08-05T19:31:44 -- 2024-08-05T20:10:44 (t_mid - T0 = 8.372 hours).
Within the enhanced XRT error circle (Goad et al., GCN 37053) close to its edge we detected a single source with the coordinates (J2000):
```
R. A. = 16:56:51.20
Dec. = +18:19:11.7 +/- 0".5
```
and brightness of R = 21.62 +/- 0.04 (calibrated against nearby SDSS stars, magnitudes converted with Lupton 2005 equations) and not corrected for Galactic extinction.
This source is located near SDSS object J165651.21+181914.0 but significantly brighter, thus it may be GRB OT.
GCN Circular #37057
M. H. Siegel (PSU) and M. Williams (PSU) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 240805B 88 s after the BAT trigger (Williams et al., GCN Circ. 37043). No optical afterglow consistent with the XRT position (Goad et al., GCN Circ. 37053) 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            88          238          147         >20.9
u_FC               301          551          246         >19.9
white               88         1719          411         >21.6
v                  630         1768          136         >19.4
b                  556         1694          117         >19.7
u                  301         1669          343         >20.2
w1                 679         1818          136         >19.6
m2                1256         1620           39         >19.2
w2                 606         1744          136         >20.1
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.087 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #37059
K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAR), T. Sbarrato (INAF-OAB), A. Tohuvavohu (U. Toronto), D.N. Burrows (PSU), J. D. Gropp (PSU) and P.A. Evans report on behalf of the Swift-XRT team:
We have analysed 8.2 ks of XRT data for GRB 240805B, from 71 s to 30.3 ks after the BAT trigger. The data comprise 4.5 ks in Windowed Timing (WT) mode (the first 6 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode.
The late-time light curve (from T0+5.6 ks) can be modelled with a power-law decay with a decay index of alpha=1.55 (+/-0.26).
A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.77 (+/-0.06). The best-fitting absorption column is 1.19 (+0.21, -0.20) x 10^21 cm^-2, in excess of the Galactic value of 7.6 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.9 (+0.4, -0.3) and a best-fitting absorption column of 1.5 (+1.4, -0.7) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.6 x 10^-11 (4.6 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     1.5 (+1.4, -0.7) x 10^21 cm^-2
Galactic foreground: 7.6 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.9 (+0.4, -0.3)
```
If the light curve continues to decay with a power-law decay index of 1.55, the count rate at T+24 hours will be 3.4 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.2 x 10^-13 (1.6 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/01246989.
This circular is an official product of the Swift-XRT team.
GCN Circular #37060
Z. Maksut (NU), B. Grossan (UCB, NU), T. Komesh (NU), Zh. Abdullayev (NU), M. Krugov (FAI) and E. Abdikamalov (NU) report on behalf of the Energetic Cosmos Laboratory:
The Nazarbayev University Transient Telescope at Assy-Turgen Astrophysical Observatory (NUTTelA-TAO) observed the field of GRB 240805B, 0.8 h after receipt an automated GCN / BAT position alert, observing in Sloan g' and r' bands, with the Burst Simultaneous Three-Channel Imager (BSTI; Grossan, Kumar & Smoot 2019, JHEA, 32, 14).
We started observations at 15:29:10 UT on 2024-08-05, 0.8 h after the BAT trigger. Observations were made in clear conditions. No source consistent with the XRT (Goad et al., GCN 37053) was detected. We report the following results:
```
start time  t-t0(h)  end time    UL g'   UL r'   exposure_time (s)
-----------------------------------------------------------------------
15:29:10     0,81     15:35:19     19.7     19.4    3x120
```
start time is in UT. t-t0(h) gives the time since trigger, in hours. UL gives the 5 sigma upper limit sensitivity in magnitudes, for images co-added to the given exposure time. Calibration was done with the 4 bright Pan-STARRS catalog stars on our images.
```
----------------------------------
NU = Nazarbayev University, Astana, Kazakhstan
UCB = University of California, Berkeley, USA
FAI = Fesenkov Astrophysical Institute, Almaty, Kazakhstan
```
This research has been funded by the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan (Grant No. AP14870504). The NUTTelA-TAO Team acknowledges the support of the staff of the Assy-Turgen Astrophysical Observatory, Almaty, Kazakhstan, and the Fesenkov Astrophysical Institute, Almaty, Kazakhstan.
GCN Circular #37062
Guowang Du (SWIFAR, YNU), Yuan Fang (SWIFAR, YNU), Yangwei Zhang (SWIFAR, YNU), Xuhui Han (NAOC), Pinpin Zhang (NAOC), Liping Xin (NAOC), Chao Wu (NAOC), Brajesh Kumar (SWIFAR, YNU), Baokun Sun (SWIFAR, YNU), Yuanpei Yang (SWIFAR, YNU), Xinzhong Er (SWIFAR, YNU), Xiangkun Liu (SWIFAR, YNU), Xiaowei Liu (SWIFAR, YNU)
We did simultaneous multi-band photometric observations of GRB 240805B (Williams et al., GCN 37043) using 1.6m Multi-channel Photometric Survey Telescope (Mephisto) of Yunnan University located at Lijiang Observatory. The observations were started at (UTC) 2024-08-05 15:46:50 and multiple frames were obtained in uvgriz bands. In our preliminary analysis the OT candidate (Moskvitin et al., GCN 37055) is detected in r, i and z bands with the following magnitudes:
```
MJD            Filter    Mag (AB)
60527.65751      r       20.3+-0.2
60527.66333      i       18.2+-0.04
60527.65751      z       17.8+-0.08
60527.66333      u       >21.1
60527.65751      v       >21.2
60527.66333      g       >20.9
```
-----------------------------------------------------------------------------------------------------Mephisto (Multi-channel Photometric Survey Telescope) is a 1.6m wide-field multi-channel telescope, the first of its type in the world, capable of imaging the same field of view in three optical bands simultaneously. It provides real-time, high-quality colors of stellar objects. The on-site telescope assemblage and commissioning were carried out in September 2022. The first light in all three channels was achieved on 2023 December 21. -----------------------------------------------------------------------------------------------------
GCN Circular #37072
N. Pankov (HSE, IKI), A. Pozanenko (IKI), V. Rumyantsev (CrAO), R. Ya. Inasaridze (AbAO), A. Shikherin (KIAM) report on behalf of GRB-IKI-FuN:
We observed the field of GRB 240805B detected by Swift (Williams et al, GCN 37043; Goad et al, GCN 37053) with AS-32 0.7-meter telescope of Abastumani observatory (AbAO) in R-filter, ZTSh 2.6-meter telescope of CrAO in R-filter, and K800 0.8-meter telescope of Terskol observatory in clear filter. The observations began on 2024-08-05 at 17:30 UT at AbAO (i.e. 3.1 hr since Swift trigger) in variable conditions. We obtain upper limits on the optical counterpart found and confirmed in (Moskvitin et al, GCN 37055; Du et al, GCN 37062):
```
Date UT start t-T0 Exp. Filter OT Err. UL Observ./Scope
(mid, days) (s) (3-sigma)
2024-08-05 17:30:52 0.14442 52x60 R n/d n/d 20.2 AbAO/AS-32
2024-08-05 19:50:58 0.24449 30*120 R n/d n/d 20.5 CrAO/ZTSh
2024-08-05 20:10:07 0.23695 44*30 CR n/d n/d 17.0 Terskol/K800
```
The photometry was calibrated against nearby stars of USNO-B1.0 (R2 magnitudes). The upper limits are in agreement with no detections by (Zhu et al, GCN 37050; Strausbaugh et al, GCN 37052; Siegel & Williams, GCN 37057; Maksut et al, GCN 37060).
GCN Circular #37074
Z.P. Zhu, X. Liu, J. An, S.Y. Fu, S.Q. Jiang, L.B. He, D. Xu (NAOC), J.Z. Liu (XAO) report on behalf of a large collaboration:
We reported JinShan optical upper limits (GCN 37050) at the Swift/XRT position of GRB 240805B (Williams et al., GCN 37043).
Later on, the Enhanced Swift-XRT position was available (Goad et al., GCN 37053), which has a quite positional shift compared to the early position (Williams et al., GCN 37043).
Checking the Enhanced Swift-XRT position in the JinShan images, we find the optical afterglow (e.g., Moskvitin et al., GCN 37055; Du et al., GCN 37062) is detected in the r-/i-/z- bands. Thus, the updated preliminary results are as follows:
```
Telescope Tmid-T0/hr Filter Exptime Mag(AB) MagErr
50D        1.683       g    20x180s  >21.5   -
100C       0.582       r     5x200s  20.03   0.06
100C       0.868       i     5x200s  18.79   0.02
100C       1.318       z     7x300s  18.79   0.02
```
We acknowledge the excellent support from S.W. Luo, M.M. Yang, Z.K. Feng, Q.C. Zhao and L.F. Huo for enabling these observations.
GCN Circular #37076
U.Quadri, L.Strabla and P.Madurini (Bassano Bresciano Astronomical Observatory),
Members of: AAVSO - American Association of Variable Star Observers. UAI - Unione Astrofili Italiani/GRB section. GAC - Gruppo Astrofili Cremonesi.
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 imaged the field of GRB 240805B detected by SWIFT (trigger num. 1246989) with the robotic telescope of (IAU station 565) Bassano Bresciano Observatory, Italy.
The observations started 6.72 hour after the GRB trigger, At the end of twilight with our Newton telescope D=450 mm F/D=4.5.
Weather conditions were good.
We co-added 2 series of 50 exposures of 20 sec each.
```
Start T0+      End T0+        Vlim
6.72 hour     7.02 hour       21.2
7.02 hour     7.35 hour       21.2
```
We did not found any optical counterpart in the error box of the XRTcandidate: M. A. Williams et al., GCN 37043; Z.P. Zhu et al., GCN 37050; V. Lipunov et al., GCN 37051; R. Strausbaugh et al., GCN 37052; A. Moskvitin et al., GCN 37055; Z. Maksut et al., GCN 37060; Guowang Du et al., GCN 37062; N. Pankov et al., GCN 37072.
Magnitudes were estimated with the pan-STARRS cat. and are derived using Lupton (2005) equations. Not corrected for galactic dust extinction.
Reference: http://www.osservatoriobassano.org/GRB.asp
The
GCN Circular #37084
H. A. Krimm (NSF), S. D. Barthelmy (GSFC), R. Gupta (GSFC), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), M. J. Moss (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC), D. Sadaula (GSFC/UMBC), T. Sakamoto (AGU)(i.e. the Swift-BAT team):
Using the data set from T-239 to T+1121 sec from the recent telemetry downlink, we report further analysis of BAT GRB 240805B (trigger #1246989) (Williams, et al., GCN Circ. 37043). The BAT ground-calculated position is RA, Dec = 254.215, 18.314 deg which is
```
   RA(J2000)  =  16h 56m 51.5s
   Dec(J2000) = +18d 18' 49.9"
```
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 85%.
The mask-weighted BAT light curve shows a complex structure with a duration of ~ 100 sec. T90 (15-350 keV) is 64.99 +- 2.56 sec (estimated error including systematics).
The time-averaged spectrum from T-0.76 to T+96.68 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.07 +- 0.26, and Epeak of 72.1 +- 12.0 keV (chi squared 38.84 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 4.5 +- 0.2 x 10^-06 erg/cm2 and the 1-sec peak flux measured from T+15.95 sec in the 15-150 keV band is 2.4 +- 0.2 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.71 +- 0.06 (chi squared 59.87 for 57 d.o.f.). 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/1246989
GCN Circular #37086
T. Mohan, R. Kumar, Y. Wagh, V. Swain, V. Bhalerao (IITB), G.C. Anupama, S. Barway (IIA) and K. Angail (IAO) report on behalf of the GIT team:
We observed the field of GRB240805B (Williams et al., GCN 37043) with the 0.7m GROWTH-India Telescope (GIT). The observations started at 2024-08-06 17:26:53 UT, 1.12 days after the Swift BAT trigger. We obtained 10 images of 240s exposure time in r' filter. We did not detect any new source in our stacked image around the coordinates reported by Swift-XRT detection (Goad et al., GCN 37053) and BTA 6-meter telescope (Moskvitin et al., GCN 37055). The obtained upper limit follows as:
```
--------------------------------------------------------------------------------------
|     JD (mid)       | t-t0 (days) | Filter | Exposure (s) | Limiting Magnitude (AB) | 
| ------------------ | ----------- |------- | ------------ | ----------------------- |
| 2460529.2419108795 |    1.14     |   r'   |   10x240     |          22.5           |
--------------------------------------------------------------------------------------
```
Our result is consistent with the upper limits reported by (Strausbaugh et al, GCN 37052; Maksut et al, GCN 37060; Pankov et al., GCN 37072; Quadri et al., GCN 37076). The magnitudes are calibrated against PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Galactic extinction.
The GROWTH India Telescope (GIT, Kumar et al. 2022) is a 70-cm telescope with a 0.7-degree field of view, set up by the Indian Institute of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and IUSSTF. It is located at the Indian Astronomical Observatory (Hanle), operated by IIA. We acknowledge funding by the IITB alumni batch of 1994, which partially supports the operations of the telescope. Telescope technical details are available at https://sites.google.com/view/growthindia/.
GCN Circular #37192
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 imaged the field of the GRB 240805B detected at 14:28:54 UT by SWIFT (trigger num. 1246989) (M. A. Williams (PSU), S. Dichiara (PSU), R. Gupta (NASA GSFC), J. A. Kennea (PSU) and D. M. Palmer (LANL) GCN 37043) 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 19:24 UT of 2024/08/05, after about 5 hours after the transient, with clear sky, with principal telescope SC 0.35 f/10 with focal reduced + CCD Sbig ST10 XME I took 45 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.
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 Start                       End        Rlim
19:24:41 UT               20:27:39 UT   19.5
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We did not found any optical counterpart.
Magnitudes were estimated with the Gaia DR2 cat. and are not corrected for galactic dust extinction.
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Jochen Greiner, last update: 16-Aug-2024 [Disclaimer]