Gamma-ray Burst 230818A

(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 18 Aug 23 23:27:46 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     1186032,   Seg_Num: 0
GRB_RA:          285.883d {+19h 03m 32s} (J2000),
                 286.076d {+19h 04m 18s} (current),
                 285.474d {+19h 01m 54s} (1950)
GRB_DEC:         +40.876d {+40d 52' 35"} (J2000),
                 +40.913d {+40d 54' 45"} (current),
                 +40.801d {+40d 48' 04"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       1498 [cnts]    Image_Peak=115 [image_cnts]
TRIGGER_DUR:     0.512 [sec] 
TRIGGER_INDEX:   47     E_range: 25-100 keV
BKG_INTEN:       18766 [cnts]
BKG_TIME:        84440.14 SOD {23:27:20.14} UT
BKG_DUR:         8 [sec]
GRB_DATE:        20174 TJD;   230 DOY;   23/08/18
GRB_TIME:        84454.35 SOD {23:27:34.35} UT
GRB_PHI:         -153.67 [deg]
GRB_THETA:        46.37 [deg]
SOLN_STATUS:     0x3
RATE_SIGNIF:     10.63 [sigma]
IMAGE_SIGNIF:    9.15 [sigma]
MERIT_PARAMS:     +1  +0  +0  -1  +2  +0  +0  +0 +39  +0 
SUN_POSTN:       148.02d {+09h 52m 05s}  +12.93d {+12d 55' 47"}
SUN_DIST:        113.66 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:      175.56d {+11h 42m 14s}   +4.90d {+04d 54' 05"}
MOON_DIST:       102.00 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       71.43, 15.24 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      296.95, 62.84 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT-BAT GRB Coordinates.  
COMMENTS:        This is a rate trigger.  
COMMENTS:        A point_source was found.  
COMMENTS:        This does not match any source in the on-board catalog.  
COMMENTS:        This does not match any source in the ground catalog.  
COMMENTS:        This is a GRB.  
COMMENTS:        This trigger occurred at longitude,latitude = 309.85,20.54 [deg].

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 18 Aug 23 23:28:04 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      46
TRIGGER_NUM:     714094060
GRB_RA:          273.100d {+18h 12m 24s} (J2000),
                 273.259d {+18h 13m 02s} (current),
                 272.763d {+18h 11m 03s} (1950)
GRB_DEC:         +47.483d {+47d 28' 60"} (J2000),
                 +47.491d {+47d 29' 26"} (current),
                 +47.469d {+47d 28' 09"} (1950)
GRB_ERROR:       6.37 [deg radius, statistical plus systematic]
GRB_INTEN:       700 [cnts/sec]
DATA_SIGNIF:     25.50 [sigma]
INTEG_TIME:      0.512 [sec]
GRB_DATE:        20174 TJD;   230 DOY;   23/08/18
GRB_TIME:        84455.37 SOD {23:27:35.37} UT
GRB_PHI:         129.00 [deg]
GRB_THETA:        70.00 [deg]
DATA_TIME_SCALE: 0.5120 [sec]
HARD_RATIO:      0.75
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      86%  GRB
2nd_MOST_LIKELY:  11%  Cyg X-1
SUN_POSTN:       148.02d {+09h 52m 05s}  +12.93d {+12d 55' 47"}
SUN_DIST:        102.42 [deg]   Sun_angle= -8.3 [hr] (East of Sun)
MOON_POSTN:      175.56d {+11h 42m 14s}   +4.90d {+04d 54' 01"}
MOON_DIST:        91.56 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       75.12, 25.98 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      276.40, 70.85 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230818977/quicklook/glg_lc_medres34_bn230818977.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(1.0<100sec) coincident with the SWIFT_BAT event (trignum=1186032).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 18 Aug 23 23:28:22 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      58
TRIGGER_NUM:     714094060
GRB_RA:          291.790d {+19h 27m 10s} (J2000),
                 291.985d {+19h 27m 56s} (current),
                 291.377d {+19h 25m 30s} (1950)
GRB_DEC:         +41.370d {+41d 22' 12"} (J2000),
                 +41.419d {+41d 25' 09"} (current),
                 +41.268d {+41d 16' 03"} (1950)
GRB_ERROR:       2.41 [deg radius, statistical only]
DATA_SIGNIF:     35.40 [sigma]
DATA_INTERVAL:   2.048 [sec]
GRB_DATE:        20174 TJD;   230 DOY;   23/08/18
GRB_TIME:        84455.37 SOD {23:27:35.37} UT
GRB_PHI:         141.00 [deg]
GRB_THETA:        79.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4173 (Gnd S/W Version number)
SUN_POSTN:       148.02d {+09h 52m 05s}  +12.93d {+12d 55' 47"}
SUN_DIST:        116.30 [deg]   Sun_angle= -9.6 [hr] (East of Sun)
MOON_POSTN:      175.56d {+11h 42m 15s}   +4.90d {+04d 53' 57"}
MOON_DIST:       106.02 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       73.79, 11.40 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      306.50, 62.08 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230818977/quicklook/glg_lc_medres34_bn230818977.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_714094060.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
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(1.0<100sec) coincident with the SWIFT_BAT event (trignum=1186032).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Fri 18 Aug 23 23:36:53 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     714094060
GRB_RA:          289.180d {+19h 16m 43s} (J2000),
                 289.375d {+19h 17m 30s} (current),
                 288.768d {+19h 15m 04s} (1950)
GRB_DEC:         +41.010d {+41d 00' 36"} (J2000),
                 +41.053d {+41d 03' 12"} (current),
                 +40.919d {+40d 55' 10"} (1950)
GRB_ERROR:       2.69 [deg radius, statistical only]
GRB_DATE:        20174 TJD;   230 DOY;   23/08/18
GRB_TIME:        84455.37 SOD {23:27:35.37} UT
GRB_PHI:         139.00 [deg]
GRB_THETA:        79.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:       148.03d {+09h 52m 06s}  +12.93d {+12d 55' 40"}
SUN_DIST:        115.28 [deg]   Sun_angle= -9.4 [hr] (East of Sun)
MOON_POSTN:      175.62d {+11h 42m 30s}   +4.87d {+04d 51' 59"}
MOON_DIST:       104.29 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       72.60, 13.02 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      302.25, 62.32 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230818977/quicklook/glg_lc_medres34_bn230818977.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230818977/quicklook/glg_locplot_all_bn230818977.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:        This is likely a Long GRB.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(1.0<100sec) coincident with the SWIFT_BAT event (trignum=1186032).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 18 Aug 23 23:30:14 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     1186032,   Seg_Num: 0
POINT_RA:        285.890d {+19h 03m 34s} (J2000)
POINT_DEC:       +40.874d {+40d 52' 27"} (J2000)
IMG_START_DATE:  20174 TJD;   230 DOY;   23/08/18
IMG_START_TIME:  84595.47 SOD {23:29:55.47} UT,   141.1 [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:     Fri 18 Aug 23 23:31:51 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     1186032,   Seg_Num: 0
GRB_RA:          285.883d {+19h 03m 32s} (J2000),
                 286.076d {+19h 04m 18s} (current),
                 285.474d {+19h 01m 54s} (1950)
GRB_DEC:         +40.876d {+40d 52' 35"} (J2000),
                 +40.913d {+40d 54' 45"} (current),
                 +40.801d {+40d 48' 04"} (1950)
GRB_DATE:        20174 TJD;   230 DOY;   23/08/18
GRB_TIME:        84454.35 SOD {23:27:34.35} UT
TRIGGER_INDEX:   47
GRB_PHI:         -153.67 [deg]
GRB_THETA:        46.37 [deg]
DELTA_TIME:      19.00 [sec]
TRIGGER_DUR:     0.512 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     10.63 [sigma]
IMAGE_SIGNIF:    9.15 [sigma]
LC_URL:          sw01186032000msb.lc
SUN_POSTN:       148.02d {+09h 52m 06s}  +12.93d {+12d 55' 44"}
SUN_DIST:        113.66 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:      175.59d {+11h 42m 21s}   +4.89d {+04d 53' 09"}
MOON_DIST:       101.99 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       71.43, 15.24 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      296.95, 62.84 [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 = 309.85,20.54 [deg].

GCN Circular #34476
V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik (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 (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 GRB230818.98 22 sec after notice time and 37 sec after trigger time at 2023-08-18 23:28:11 UT. On our first (10s exposure) set we found 1 optical transient within Swift error-box (ra=285.879 dec=40.8758 r=0.05) brighter than 16.8.
```
 T-Tmid      Date      Time       Expt.        Ra                Dec           Mag
---------|---------------------|-------|-----------------|-----------------|-------
      42   2023-08-18 23:28:11      10   (19h 03m 33.11s , +40d 53m 48.5s)     15.5
```
The 5-sigma upper limit has been about 16.8mag The message may be cited.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 18 Aug 23 23:33:00 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1186032,   Seg_Num: 0
POINT_RA:        285.890d {+19h 03m 34s} (J2000)
POINT_DEC:       +40.874d {+40d 52' 26"} (J2000)
POINT_ROLL:      314.508d
IMG_START_DATE:  20174 TJD;   230 DOY;   23/08/18
IMG_START_TIME:  84598.46 SOD {23:29:58.46} UT,   144.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.588
N_STARS:         190
X_OFFSET:        503 [pixels]
Y_OFFSET:        512 [pixels]
X_MAX:           1462 [pixels]
Y_MAX:           1471 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw01186032000msufc0144.fits
SUN_POSTN:       148.02d {+09h 52m 06s}  +12.93d {+12d 55' 43"}
SUN_DIST:        113.66 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:      175.60d {+11h 42m 23s}   +4.88d {+04d 52' 53"}
MOON_DIST:       102.00 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       71.43, 15.24 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      296.96, 62.83 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 18 Aug 23 23:33:09 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1186032,   Seg_Num: 0
POINT_RA:        285.890d {+19h 03m 34s} (J2000)
POINT_DEC:       +40.874d {+40d 52' 26"} (J2000)
POINT_ROLL:      314.508d
IMG_START_DATE:  20174 TJD;   230 DOY;   23/08/18
IMG_START_TIME:  84598.46 SOD {23:29:58.46} UT,   144.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.588
N_STARS:         190
X_OFFSET:        503 [pixels]
Y_OFFSET:        512 [pixels]
X_MAX:           1462 [pixels]
Y_MAX:           1471 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw01186032000msufc0144.fits
SUN_POSTN:       148.02d {+09h 52m 06s}  +12.93d {+12d 55' 43"}
SUN_DIST:        113.66 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:      175.60d {+11h 42m 23s}   +4.88d {+04d 52' 51"}
MOON_DIST:       101.99 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       71.43, 15.24 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      296.96, 62.83 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_srclist.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 18 Aug 23 23:34:17 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1186032,   Seg_Num: 0
POINT_RA:        285.890d {+19h 03m 34s} (J2000)
POINT_DEC:       +40.874d {+40d 52' 26"} (J2000)
ROLL:            314.508d
IMG_START_DATE:  20174 TJD;   230 DOY;   23/08/18
IMG_START_TIME:  84598.46 SOD {23:29:58.46} UT,   144.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     714094230
X_OFFSET:        822 [pixels]
Y_OFFSET:        831 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       982
Y_GRB_POS:       991
BINNING_INDEX:   1
IM_URL:          sw01186032000msuni0176.fits
SUN_POSTN:       148.02d {+09h 52m 06s}  +12.93d {+12d 55' 42"}
SUN_DIST:        113.66 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:      175.61d {+11h 42m 25s}   +4.88d {+04d 52' 35"}
MOON_DIST:       101.99 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       71.43, 15.24 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      296.96, 62.83 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Fri 18 Aug 23 23:34:29 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1186032,   Seg_Num: 0
POINT_RA:        285.890d {+19h 03m 34s} (J2000)
POINT_DEC:       +40.874d {+40d 52' 26"} (J2000)
ROLL:            314.508d
IMG_START_DATE:  20174 TJD;   230 DOY;   23/08/18
IMG_START_TIME:  84598.46 SOD {23:29:58.46} UT,   144.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     714094230
X_OFFSET:        822 [pixels]
Y_OFFSET:        831 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       982
Y_GRB_POS:       991
BINNING_INDEX:   1
IM_URL:          sw01186032000msuni0176.fits
SUN_POSTN:       148.02d {+09h 52m 06s}  +12.93d {+12d 55' 42"}
SUN_DIST:        113.66 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:      175.61d {+11h 42m 26s}   +4.88d {+04d 52' 32"}
MOON_DIST:       101.99 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       71.43, 15.24 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      296.96, 62.83 [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:     Fri 18 Aug 23 23:35:03 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     1186032,   Seg_Num: 0
GRB_RA:          285.8890d {+19h 03m 33.36s} (J2000),
                 286.0822d {+19h 04m 19.72s} (current),
                 285.4803d {+19h 01m 55.27s} (1950)
GRB_DEC:         +40.8948d {+40d 53' 41.2"} (J2000),
                 +40.9310d {+40d 55' 51.7"} (current),
                 +40.8195d {+40d 49' 10.3"} (1950)
GRB_ERROR:       4.3 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  20174 TJD;   230 DOY;   23/08/18
IMG_START_TIME:  84642.00 SOD {23:30:42.00} UT,   187.6 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       148.03d {+09h 52m 06s}  +12.93d {+12d 55' 42"}
SUN_DIST:        113.65 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:      175.61d {+11h 42m 27s}   +4.87d {+04d 52' 24"}
MOON_DIST:       101.98 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       71.45, 15.25 [deg] galactic lon,lat of the burst
ECL_COORDS:      296.97, 62.85 [deg] ecliptic lon,lat of the burst
COMMENTS:        SWIFT-XRT Coordinates.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        TAM values, flux and significance fields are not valid.  
COMMENTS:        This position was automatically generated on the ground using  
COMMENTS:        Photon Counting data telemetered via TDRSS (SPER data).  
COMMENTS:        See http://www.swift.ac.uk/sper/docs.php for details.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.58% < P(seren) < 1.1%.

GCN Circular #34477
V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin (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 (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),
A. Gabovich, V.Yurkov (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 GRB230818.98 (trigger No 1186032,19h 03m 31.90s , +40d 52m 34.7s, R=0.05) errorbox 19 sec after notice time and 37 sec after trigger time at 2023-08-18 23:28:11 UT, with upper limit up to 18.6 mag. The observations began at zenith distance = 48 deg. The sun altitude is -28.4 deg.
MASTER-Kislovodsk robotic telescope located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the Swift GRB230818.98 errorbox 24 sec after notice time and 41 sec after trigger time at 2023-08-18 23:28:15 UT, with upper limit up to 17.9 mag. The observations began at zenith distance = 54 deg. The sun altitude is -26.2 deg.
The galactic latitude b = 15 deg., longitude l = 72 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2256038
We obtain a following upper limits.
```
Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

      42 |      MASTER-Tavrida |   C |    10 | 17.3 |        
      47 |   MASTER-Kislovodsk |  P- |    10 | 14.2 |        
      47 |   MASTER-Kislovodsk |  P| |    10 | 16.4 |        
      57 |   MASTER-Kislovodsk |  P| |    30 | 17.1 |  Coadd 
      59 |      MASTER-Tavrida |   C |    10 | 17.9 |        
      65 |   MASTER-Kislovodsk |  P- |    10 | 14.2 |        
      65 |   MASTER-Kislovodsk |  P| |    10 | 16.5 |        
      76 |      MASTER-Tavrida |   C |    10 | 18.0 |        
      83 |   MASTER-Kislovodsk |  P- |    10 | 14.5 |        
      83 |   MASTER-Kislovodsk |  P| |    10 | 16.5 |        
      99 |      MASTER-Tavrida |   C |    20 | 18.3 |        
     105 |   MASTER-Kislovodsk |  P- |    20 | 16.0 |        
     105 |   MASTER-Kislovodsk |  P| |    20 | 17.2 |        
     130 |   MASTER-Kislovodsk |  P| |    70 | 17.8 |  Coadd 
     126 |      MASTER-Tavrida |   C |    20 | 18.3 |        
     134 |   MASTER-Kislovodsk |  P- |    20 | 16.0 |        
     134 |   MASTER-Kislovodsk |  P| |    20 | 17.0 |        
     159 |      MASTER-Tavrida |   C |    30 | 18.4 |        
     167 |   MASTER-Kislovodsk |  P- |    30 | 16.1 |        
     167 |   MASTER-Kislovodsk |  P| |    30 | 17.5 |        
     201 |      MASTER-Tavrida |   C |    40 | 18.6 |        
     210 |   MASTER-Kislovodsk |  P- |    40 | 16.1 |        
     210 |   MASTER-Kislovodsk |  P| |    40 | 17.7 |        
     253 |      MASTER-Tavrida |   C |    50 | 18.6 |        
     263 |   MASTER-Kislovodsk |  P- |    50 | 16.2 |        
     263 |   MASTER-Kislovodsk |  P| |    50 | 17.8 |        
     326 |   MASTER-Kislovodsk |  P- |    60 | 16.2 |        
     326 |   MASTER-Kislovodsk |  P| |    60 | 17.9 |        
```
Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
GCN Circular #34478
The Fermi GBM team reports the detection of a likely LONG GRB
At 23:27:35 UT on 18 Aug 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230818A (trigger 714094060.372856 / 230818977).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 289.2, Dec = 41.0 (J2000 degrees, equivalent to J2000 19h 16m, 41d 00'), with a statistical uncertainty of 2.7 degrees.
The angle from the Fermi LAT boresight is 79.0 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230818977/quicklook/glg_skymap_all_bn230818977.png
The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230818977/quicklook/glg_healpix_all_bn230818977.fit
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230818977/quicklook/glg_lc_medres34_bn230818977.gif
GCN Circular #34479
A. Tohuvavohu (U Toronto), S. Dichiara (PSU), J.D. Gropp (PSU), D. M. Palmer (LANL), T. M. Parsotan (GSFC/UMBC/CRESSTII), B. Sbarufatti (INAF-OAB) and M. A. Williams (PSU) report on behalf of the Neil Gehrels Swift Observatory Team:
At 23:27:34 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 230818A (trigger=1186032). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 285.883, +40.876 which is
```
   RA(J2000) = 19h 03m 32s
   Dec(J2000) = +40d 52' 35"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single complex peak structure with a duration of about 10 sec. The peak count rate was ~6000 counts/sec (15-350 keV), at ~1 sec after the trigger.
The XRT began observing the field at 23:29:55.4 UT, 141.1 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 285.88966, 40.89504 which is equivalent to:
```
   RA(J2000)  = 19h 03m 33.52s
   Dec(J2000) = +40d 53' 42.1"
```
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 70 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.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 1.13 x 10^21 cm^-2 (Willingale et al. 2013).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 144 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. Results 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 0.101.
Burst Advocate for this burst is A. Tohuvavohu (aaron.tohu AT gmail.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:     Sat 19 Aug 23 00:08:09 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     1186032,   Seg_Num: 0
GRB_RA:          285.8895d {+19h 03m 33.47s} (J2000),
                 286.0827d {+19h 04m 19.84s} (current),
                 285.4808d {+19h 01m 55.39s} (1950)
GRB_DEC:         +40.8953d {+40d 53' 43.0"} (J2000),
                 +40.9315d {+40d 55' 53.5"} (current),
                 +40.8200d {+40d 49' 12.1"} (1950)
GRB_ERROR:       3.6 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  20174 TJD;   230 DOY;   23/08/18
IMG_START_TIME:  84642.00 SOD {23:30:42.00} UT,   187.6 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:       148.05d {+09h 52m 11s}  +12.92d {+12d 55' 15"}
SUN_DIST:        113.64 [deg]   Sun_angle= -9.2 [hr] (East of Sun)
MOON_POSTN:      175.85d {+11h 43m 25s}   +4.75d {+04d 44' 46"}
MOON_DIST:       101.89 [deg]
MOON_ILLUM:      6 [%]
GAL_COORDS:       71.45, 15.25 [deg] galactic lon,lat of the burst
ECL_COORDS:      296.97, 62.85 [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 0.58% < P(seren) < 1.1%.

GCN Circular #34480
B. P. Gompertz, A. Kumar, K. Wiersema, B. Godson, D. O=E2=80=99Neill, B. Warwick, R. Starling, K. Ackley; M. J. Dyer; J. Lyman; K. Ulaczyk; F. Jimenez -Ibarra; D. Steeghs; D. K. Galloway; V. Dhillon; P. O'Brien; G. Ramsay; K. Noysena; R. Kotak; R. P. Breton; L. K. Nuttall; E. Pall'e and D. Pollacco report on behalf of the GOTO collaboration:
The Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2022) observed the field of the X-ray (Tohuvavohu et al., GCN 34479) and optical (Lipunov et al, GCN 34476) counterparts to GRB 230818A (Fermi GBM Team, GCN 34478; Tohuvavohu et al., GCN 34479) at 23:32:00 UT on 2023-08-18, 266 seconds after trigger. The observation consisted of 4x90s exposures in the GOTO L-band (400-700 nm).
Images were processed immediately after acquisition using the GOTO pipeline. Difference imaging was performed using recent survey observations of the same pointing. We detect the optical counterpart reported by MASTER (GCN 34476) with a preliminary magnitude of L = 17.75 =C2=B1 0.02 mag.
Magnitudes were calibrated using ATLAS-REFCAT2 (Tonry et al. 2018) and are not corrected for Galactic extinction.
Observations are ongoing. GOTO (https://goto-observatory.org) is a network of telescopes operated at the Roque de los Muchachos Observatory on La Palma, Spain, and Siding Spring Observatory in NSW, Australia, on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory & Planetarium, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT), the University of Turku, the University of Portsmouth, the University of Manchester and the Instituto de Astrofisica de Canarias (IAC).

GCN Circular #34481
V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin (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 (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),
A. Gabovich, V.Yurkov (Blagoveschensk Educational State University)
MASTER-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB230817.60 (trigger No 713974668,07h 55m 24.00s , +21d 31m 01.2s, R=28.7) errorbox 1 days 19084 sec after notice time and 1 days 19116 sec after trigger time at 2023-08-18 19:36:20 UT, with upper limit up to 18.2 mag. The observations began at zenith distance = 85 deg. The sun altitude is -29.6 deg.
The galactic latitude b = 24 deg., longitude l = 200 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2255394
We obtain a following upper limits.

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

  105581 | 2023-08-18 19:36:20 |   MASTER-Kislovodsk | (07h 40m 42.00s , +51d 55m 13.4s) |   C |   130 | 15.8 |        
  117523 | 2023-08-18 22:55:56 |   MASTER-Kislovodsk | (07h 10m 31.31s , +50d 35m 24.8s) |   C |    60 | 17.1 |        
  117523 | 2023-08-18 22:55:56 |   MASTER-Kislovodsk | (07h 16m 47.71s , +50d 11m 52.6s) |   C |    60 | 17.2 |        
  117884 | 2023-08-18 23:01:57 |   MASTER-Kislovodsk | (07h 10m 38.53s , +50d 37m 26.1s) |   C |    60 | 17.2 |        
  117884 | 2023-08-18 23:01:57 |   MASTER-Kislovodsk | (07h 16m 49.66s , +50d 13m 06.0s) |   C |    60 | 18.0 |        
  118666 | 2023-08-18 23:14:59 |   MASTER-Kislovodsk | (07h 10m 40.32s , +50d 36m 22.2s) |   C |    60 | 17.2 |        
  120068 | 2023-08-18 23:38:12 |   MASTER-Kislovodsk | (06h 37m 26.81s , +35d 17m 51.2s) |   C |    80 | 17.2 |        
  120178 | 2023-08-18 23:38:12 |   MASTER-Kislovodsk | (06h 37m 26.81s , +35d 17m 51.2s) |   C |   300 | 18.2 |  Coadd 
  120068 | 2023-08-18 23:38:12 |   MASTER-Kislovodsk | (06h 42m 06.50s , +34d 55m 52.2s) |   C |    80 | 16.3 |        
  120179 | 2023-08-18 23:39:52 |   MASTER-Kislovodsk | (06h 37m 32.83s , +35d 16m 47.4s) |   C |   100 | 17.6 |        
  120179 | 2023-08-18 23:39:52 |   MASTER-Kislovodsk | (06h 42m 12.51s , +34d 54m 30.9s) |   C |   100 | 17.2 |        
  120309 | 2023-08-18 23:41:52 |   MASTER-Kislovodsk | (06h 37m 27.81s , +35d 15m 48.8s) |   C |   120 | 17.8 |        
  120309 | 2023-08-18 23:41:52 |   MASTER-Kislovodsk | (06h 42m 07.54s , +34d 53m 22.0s) |   C |   120 | 18.0 |        
  120464 | 2023-08-18 23:44:12 |   MASTER-Kislovodsk | (06h 37m 33.76s , +35d 15m 57.1s) |   C |   150 | 17.9 |        
  120464 | 2023-08-18 23:44:12 |   MASTER-Kislovodsk | (06h 42m 13.65s , +34d 53m 24.8s) |   C |   150 | 18.2 |

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

GCN Circular #34482
V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin (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 (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),
A. Gabovich, V.Yurkov (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) started inspect of the Fermi GRB 230818A ( Fermi GBM team, GCN 34478) errorbox 2 sec after notice time and 36 sec after trigger time at 2023-08-18 23:28:11 UT, with upper limit up to 19.1 mag. The observations began at zenith distance = 48 deg. The sun altitude is -28.4 deg.
MASTER-OAFA robotic telescope located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 230818A errorbox 5 sec after notice time and 38 sec after trigger time at 2023-08-18 23:28:14 UT, with upper limit up to 18.1 mag. The observations began at zenith distance = 79 deg. The sun altitude is -17.2 deg.
MASTER-Kislovodsk robotic telescope located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 230818A errorbox 7 sec after notice time and 40 sec after trigger time at 2023-08-18 23:28:15 UT, with upper limit up to 19.2 mag. The observations began at zenith distance = 54 deg. The sun altitude is -26.2 deg.
The galactic latitude b = 13 deg., longitude l = 73 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2256099
We obtain a following upper limits.

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

      41 | 2023-08-18 23:28:11 |      MASTER-Tavrida | (19h 04m 27.69s , +40d 41m 46.2s) |   C |    10 | 17.3 |        
      44 | 2023-08-18 23:28:14 |         MASTER-OAFA | (19h 02m 32.62s , +40d 55m 41.9s) |   C |    10 | 15.8 |        
      89 | 2023-08-18 23:28:14 |         MASTER-OAFA | (19h 02m 32.61s , +40d 55m 41.9s) |   C |   100 | 17.1 |  Coadd 
     189 | 2023-08-18 23:28:14 |         MASTER-OAFA | (19h 02m 32.61s , +40d 55m 41.9s) |   C |   300 | 17.6 |  Coadd 
      46 | 2023-08-18 23:28:15 |   MASTER-Kislovodsk | (19h 03m 26.12s , +40d 50m 05.7s) |  P- |    10 | 14.2 |        
      46 | 2023-08-18 23:28:15 |   MASTER-Kislovodsk | (19h 03m 25.92s , +41d 13m 18.9s) |  P| |    10 | 16.4 |        
      56 | 2023-08-18 23:28:15 |   MASTER-Kislovodsk | (19h 03m 25.92s , +41d 13m 18.9s) |  P| |    30 | 17.1 |  Coadd 
     166 | 2023-08-18 23:28:15 |   MASTER-Kislovodsk | (19h 03m 25.91s , +41d 13m 18.9s) |  P| |   250 | 18.5 |  Coadd 
      58 | 2023-08-18 23:28:28 |      MASTER-Tavrida | (19h 04m 22.05s , +40d 40m 49.5s) |   C |    10 | 17.9 |        
      64 | 2023-08-18 23:28:33 |   MASTER-Kislovodsk | (19h 03m 23.93s , +40d 51m 33.7s) |  P- |    10 | 14.2 |        
      64 | 2023-08-18 23:28:33 |   MASTER-Kislovodsk | (19h 03m 23.75s , +41d 14m 47.2s) |  P| |    10 | 16.5 |        
      75 | 2023-08-18 23:28:45 |      MASTER-Tavrida | (19h 04m 22.15s , +40d 41m 48.6s) |   C |    10 | 18.0 |        
      81 | 2023-08-18 23:28:51 |   MASTER-Kislovodsk | (19h 03m 23.92s , +40d 50m 10.0s) |  P- |    10 | 14.5 |        
      82 | 2023-08-18 23:28:51 |   MASTER-Kislovodsk | (19h 03m 23.78s , +41d 13m 23.0s) |  P| |    10 | 16.5 |        
      98 | 2023-08-18 23:29:02 |      MASTER-Tavrida | (19h 04m 27.53s , +40d 40m 46.6s) |   C |    20 | 18.3 |        
      94 | 2023-08-18 23:29:03 |         MASTER-OAFA | (19h 02m 38.15s , +40d 54m 46.1s) |   C |    10 | 15.6 |        
     104 | 2023-08-18 23:29:09 |   MASTER-Kislovodsk | (19h 03m 26.06s , +40d 51m 22.5s) |  P- |    20 | 16.0 |        
     104 | 2023-08-18 23:29:09 |   MASTER-Kislovodsk | (19h 03m 25.95s , +41d 14m 36.8s) |  P| |    20 | 17.2 |        
     129 | 2023-08-18 23:29:09 |   MASTER-Kislovodsk | (19h 03m 25.95s , +41d 14m 36.8s) |  P| |    70 | 17.8 |  Coadd 
     125 | 2023-08-18 23:29:30 |      MASTER-Tavrida | (19h 04m 22.51s , +40d 39m 45.1s) |   C |    20 | 18.3 |        
     133 | 2023-08-18 23:29:38 |   MASTER-Kislovodsk | (19h 03m 20.94s , +40d 50m 50.5s) |  P- |    20 | 16.0 |        
     133 | 2023-08-18 23:29:38 |   MASTER-Kislovodsk | (19h 03m 20.93s , +41d 14m 04.7s) |  P| |    20 | 17.0 |        
     150 | 2023-08-18 23:29:50 |         MASTER-OAFA | (19h 02m 33.15s , +40d 53m 48.4s) |   C |    30 | 16.2 |        
     158 | 2023-08-18 23:29:57 |      MASTER-Tavrida | (19h 04m 27.91s , +40d 39m 58.3s) |   C |    30 | 18.4 |        
     166 | 2023-08-18 23:30:06 |   MASTER-Kislovodsk | (19h 03m 20.88s , +40d 51m 47.9s) |  P- |    30 | 16.1 |        
     166 | 2023-08-18 23:30:06 |   MASTER-Kislovodsk | (19h 03m 20.92s , +41d 15m 01.9s) |  P| |    30 | 17.5 |        
     200 | 2023-08-18 23:30:35 |      MASTER-Tavrida | (19h 04m 25.14s , +40d 41m 36.2s) |   C |    40 | 18.6 |        
     209 | 2023-08-18 23:30:44 |   MASTER-Kislovodsk | (19h 03m 26.59s , +40d 50m 47.8s) |  P- |    40 | 16.1 |        
     209 | 2023-08-18 23:30:44 |   MASTER-Kislovodsk | (19h 03m 26.71s , +41d 14m 01.5s) |  P| |    40 | 17.7 |        
     264 | 2023-08-18 23:30:44 |   MASTER-Kislovodsk | (19h 03m 26.70s , +41d 14m 01.5s) |  P| |   150 | 18.3 |  Coadd 
     225 | 2023-08-18 23:31:00 |         MASTER-OAFA | (19h 02m 39.38s , +40d 53m 58.2s) |   C |    40 | 16.6 |        
     252 | 2023-08-18 23:31:22 |      MASTER-Tavrida | (19h 04m 25.14s , +40d 39m 55.8s) |   C |    50 | 18.6 |        
     262 | 2023-08-18 23:31:32 |   MASTER-Kislovodsk | (19h 03m 20.78s , +40d 49m 45.3s) |  P- |    50 | 16.2 |        
     262 | 2023-08-18 23:31:32 |   MASTER-Kislovodsk | (19h 03m 21.04s , +41d 12m 58.3s) |  P| |    50 | 17.8 |        
     289 | 2023-08-18 23:31:59 |         MASTER-OAFA | (19h 02m 35.47s , +40d 55m 39.5s) |   C |    50 | 16.8 |        
     315 | 2023-08-18 23:32:20 |      MASTER-Tavrida | (19h 04m 28.52s , +40d 41m 33.0s) |   C |    60 | 18.8 |        
     325 | 2023-08-18 23:32:30 |   MASTER-Kislovodsk | (19h 03m 25.74s , +40d 50m 06.7s) |  P- |    60 | 16.2 |        
     325 | 2023-08-18 23:32:30 |   MASTER-Kislovodsk | (19h 03m 26.12s , +41d 13m 19.2s) |  P| |    60 | 17.9 |        
     387 | 2023-08-18 23:33:27 |      MASTER-Tavrida | (19h 04m 22.43s , +40d 40m 31.1s) |   C |    70 | 18.9 |        
     389 | 2023-08-18 23:33:29 |         MASTER-OAFA | (19h 02m 35.66s , +40d 54m 01.9s) |   C |    70 | 16.8 |        
     398 | 2023-08-18 23:33:38 |   MASTER-Kislovodsk | (19h 04m 24.74s , +41d 13m 15.6s) |  P| |    70 | 12.3 |        
     475 | 2023-08-18 23:34:45 |      MASTER-Tavrida | (19h 04m 21.84s , +40d 41m 27.3s) |   C |    90 | 19.0 |        
     489 | 2023-08-18 23:34:59 |         MASTER-OAFA | (19h 02m 39.29s , +40d 55m 39.9s) |   C |    90 | 17.0 |        
     534 | 2023-08-18 23:34:59 |         MASTER-OAFA | (19h 02m 39.29s , +40d 55m 39.8s) |   C |   180 | 17.3 |  Coadd 
     585 | 2023-08-18 23:36:24 |      MASTER-Tavrida | (19h 04m 27.65s , +40d 40m 22.8s) |   C |   110 | 19.0 |        
     628 | 2023-08-18 23:37:08 |         MASTER-OAFA | (19h 02m 31.74s , +40d 54m 56.2s) |   C |   110 | 17.2 |        
     712 | 2023-08-18 23:38:22 |      MASTER-Tavrida | (19h 04m 22.34s , +40d 39m 18.4s) |   C |   130 | 19.0 |        
     773 | 2023-08-18 23:39:18 |         MASTER-OAFA | (19h 02m 32.53s , +40d 55m 57.9s) |   C |   140 | 17.1 |        
     867 | 2023-08-18 23:40:42 |      MASTER-Tavrida | (19h 04m 28.58s , +40d 39m 31.5s) |   C |   160 | 19.1 |        
     967 | 2023-08-18 23:42:17 |         MASTER-OAFA | (19h 02m 38.09s , +40d 54m 58.5s) |   C |   170 | 17.3 |        
    1045 | 2023-08-18 23:43:30 |      MASTER-Tavrida | (19h 04m 25.91s , +40d 41m 04.7s) |   C |   180 | 19.1 |        
    1162 | 2023-08-18 23:45:27 |         MASTER-OAFA | (19h 02m 31.91s , +40d 54m 00.8s) |   C |   180 | 16.8 |        
    1233 | 2023-08-18 23:46:38 |      MASTER-Tavrida | (19h 04m 26.01s , +40d 39m 01.5s) |   C |   180 | 19.1 |        
    1258 | 2023-08-18 23:47:03 |   MASTER-Kislovodsk | (19h 03m 21.94s , +40d 53m 32.1s) |   C |   180 | 16.6 |        
    1258 | 2023-08-18 23:47:03 |   MASTER-Kislovodsk | (19h 03m 26.43s , +41d 17m 09.3s) |   C |   180 | 18.1 |        
    1423 | 2023-08-18 23:49:48 |      MASTER-Tavrida | (19h 04m 29.85s , +40d 40m 44.6s) |   C |   180 | 19.0 |        
    1459 | 2023-08-18 23:50:23 |   MASTER-Kislovodsk | (19h 03m 21.84s , +40d 51m 33.0s) |   C |   180 | 18.1 |        
    1639 | 2023-08-18 23:50:23 |   MASTER-Kislovodsk | (19h 03m 21.84s , +40d 51m 33.0s) |   C |   540 | 18.8 |  Coadd 
    1459 | 2023-08-18 23:50:23 |   MASTER-Kislovodsk | (19h 03m 26.64s , +41d 15m 12.7s) |   C |   180 | 18.5 |        
    1612 | 2023-08-18 23:52:57 |      MASTER-Tavrida | (19h 04m 22.42s , +40d 39m 49.1s) |   C |   180 | 19.1 |        
    1659 | 2023-08-18 23:53:44 |   MASTER-Kislovodsk | (19h 03m 24.49s , +40d 53m 10.0s) |   C |   180 | 18.2 |        
    1659 | 2023-08-18 23:53:44 |   MASTER-Kislovodsk | (19h 03m 29.72s , +41d 16m 49.4s) |   C |   180 | 18.5 |        
    1839 | 2023-08-18 23:53:44 |   MASTER-Kislovodsk | (19h 03m 29.72s , +41d 16m 49.2s) |   C |   540 | 19.2 |  Coadd 
    1802 | 2023-08-18 23:56:06 |      MASTER-Tavrida | (19h 04m 24.04s , +40d 40m 43.5s) |   C |   180 | 19.0 |        
    1991 | 2023-08-18 23:59:16 |      MASTER-Tavrida | (19h 04m 30.28s , +40d 39m 37.6s) |   C |   180 | 19.0 |        
    2066 | 2023-08-19 00:00:31 |   MASTER-Kislovodsk | (19h 03m 19.42s , +40d 53m 01.7s) |   C |   180 | 18.3 |        
    2066 | 2023-08-19 00:00:31 |   MASTER-Kislovodsk | (19h 03m 25.40s , +41d 16m 38.0s) |   C |   180 | 18.6 |        
    2181 | 2023-08-19 00:02:26 |      MASTER-Tavrida | (19h 04m 23.56s , +40d 38m 32.6s) |   C |   180 | 19.0 |        
    2267 | 2023-08-19 00:03:52 |   MASTER-Kislovodsk | (19h 03m 24.05s , +40d 51m 55.1s) |   C |   180 | 18.3 |        
    2447 | 2023-08-19 00:03:52 |   MASTER-Kislovodsk | (19h 03m 24.02s , +40d 51m 55.0s) |   C |   540 | 18.3 |  Coadd 
    2267 | 2023-08-19 00:03:52 |   MASTER-Kislovodsk | (19h 03m 30.34s , +41d 15m 31.0s) |   C |   180 | 18.7 |        
    2371 | 2023-08-19 00:05:36 |      MASTER-Tavrida | (19h 04m 29.48s , +40d 38m 45.7s) |   C |   180 | 19.0 |        
    2553 | 2023-08-19 00:08:38 |   MASTER-Kislovodsk | (19h 03m 26.78s , +40d 51m 59.9s) |  P- |   180 | 17.1 |        
    2553 | 2023-08-19 00:08:38 |   MASTER-Kislovodsk | (19h 03m 33.03s , +41d 15m 28.9s) |  P| |   180 | 18.1 |        
    2733 | 2023-08-19 00:08:38 |   MASTER-Kislovodsk | (19h 03m 33.03s , +41d 15m 28.9s) |  P| |   540 | 18.7 |  Coadd 
    2560 | 2023-08-19 00:08:45 |      MASTER-Tavrida | (19h 04m 27.19s , +40d 40m 02.0s) |   C |   180 | 18.9 |        
    2642 | 2023-08-19 00:10:07 |         MASTER-OAFA | (19h 02m 31.47s , +40d 55m 53.4s) |   C |   180 | 17.6 |        
    2748 | 2023-08-19 00:11:53 |      MASTER-Tavrida | (19h 04m 27.32s , +40d 38m 25.3s) |   C |   180 | 18.9 |        
    2753 | 2023-08-19 00:11:58 |   MASTER-Kislovodsk | (19h 03m 23.68s , +40d 53m 29.5s) |  P- |   180 | 17.2 |        
    2753 | 2023-08-19 00:11:58 |   MASTER-Kislovodsk | (19h 03m 30.38s , +41d 16m 58.6s) |  P| |   180 | 18.2 |        
    2877 | 2023-08-19 00:14:02 |         MASTER-OAFA | (19h 02m 37.86s , +40d 54m 57.1s) |   C |   180 | 17.8 |        
    2936 | 2023-08-19 00:15:01 |      MASTER-Tavrida | (19h 04m 30.09s , +40d 39m 46.5s) |   C |   180 | 18.8 |        
    2954 | 2023-08-19 00:15:19 |   MASTER-Kislovodsk | (19h 03m 23.50s , +40d 51m 43.7s) |  P- |   180 | 17.0 |        
    3134 | 2023-08-19 00:15:19 |   MASTER-Kislovodsk | (19h 03m 23.50s , +40d 51m 43.6s) |  P- |   540 | 17.6 |  Coadd 
    2954 | 2023-08-19 00:15:19 |   MASTER-Kislovodsk | (19h 03m 30.67s , +41d 15m 13.6s) |  P| |   180 | 18.2 |        
    3114 | 2023-08-19 00:17:59 |         MASTER-OAFA | (19h 02m 31.97s , +40d 53m 59.3s) |   C |   180 | 17.9 |        
    3123 | 2023-08-19 00:18:08 |      MASTER-Tavrida | (19h 04m 24.56s , +40d 39m 05.8s) |   C |   180 | 18.8 |        
    3155 | 2023-08-19 00:18:39 |   MASTER-Kislovodsk | (19h 03m 26.10s , +40d 53m 01.5s) |  P- |   180 | 17.1 |        
    3155 | 2023-08-19 00:18:39 |   MASTER-Kislovodsk | (19h 03m 33.83s , +41d 16m 32.2s) |  P| |   180 | 18.1 |        
    3335 | 2023-08-19 00:18:39 |   MASTER-Kislovodsk | (19h 03m 33.83s , +41d 16m 32.3s) |  P| |   540 | 18.6 |  Coadd 
    3311 | 2023-08-19 00:21:15 |      MASTER-Tavrida | (19h 04m 24.82s , +40d 40m 00.4s) |   C |   180 | 18.7 |        
    3355 | 2023-08-19 00:22:00 |   MASTER-Kislovodsk | (19h 03m 19.81s , +40d 52m 23.1s) |  P- |   180 | 17.0 |        
    3355 | 2023-08-19 00:22:00 |   MASTER-Kislovodsk | (19h 03m 28.06s , +41d 15m 54.1s) |  P| |   180 | 18.1 |        
    3498 | 2023-08-19 00:24:23 |      MASTER-Tavrida | (19h 04m 31.83s , +40d 38m 54.8s) |   C |   180 | 18.6 |        
    3516 | 2023-08-19 00:24:41 |         MASTER-OAFA | (19h 02m 34.21s , +40d 55m 52.1s) |   C |   180 | 17.8 |        
    3555 | 2023-08-19 00:25:20 |   MASTER-Kislovodsk | (19h 03m 18.96s , +40d 53m 14.5s) |  P- |   180 | 17.0 |        
    3735 | 2023-08-19 00:25:20 |   MASTER-Kislovodsk | (19h 03m 18.96s , +40d 53m 14.5s) |  P- |   540 | 17.5 |  Coadd 
    3555 | 2023-08-19 00:25:20 |   MASTER-Kislovodsk | (19h 03m 27.59s , +41d 16m 45.5s) |  P| |   180 | 18.0 |        
    3686 | 2023-08-19 00:27:31 |      MASTER-Tavrida | (19h 04m 26.57s , +40d 37m 50.4s) |   C |   180 | 18.6 |        
    3715 | 2023-08-19 00:28:00 |         MASTER-OAFA | (19h 02m 34.00s , +40d 54m 26.3s) |   C |   180 | 17.9 |        
    3756 | 2023-08-19 00:28:41 |   MASTER-Kislovodsk | (19h 03m 25.70s , +40d 52m 09.0s) |  P- |   180 | 17.0 |        
    3756 | 2023-08-19 00:28:41 |   MASTER-Kislovodsk | (19h 03m 34.73s , +41d 15m 39.4s) |  P| |   180 | 18.0 |        
    3936 | 2023-08-19 00:28:41 |   MASTER-Kislovodsk | (19h 03m 34.73s , +41d 15m 39.4s) |  P| |   540 | 18.5 |  Coadd 
    3877 | 2023-08-19 00:30:42 |      MASTER-Tavrida | (19h 04m 31.80s , +40d 37m 54.0s) |   C |   180 | 18.6 |        
    3956 | 2023-08-19 00:32:01 |   MASTER-Kislovodsk | (19h 03m 19.48s , +40d 51m 00.6s) |  P- |   180 | 17.0 |        
    3956 | 2023-08-19 00:32:01 |   MASTER-Kislovodsk | (19h 03m 28.95s , +41d 14m 31.0s) |  P| |   180 | 18.0 |        
    3989 | 2023-08-19 00:32:33 |         MASTER-OAFA | (19h 02m 36.07s , +40d 55m 58.0s) |   C |   180 | 17.5 |        
    4034 | 2023-08-19 00:33:19 |         MASTER-OAFA | (19h 02m 37.30s , +40d 55m 01.6s) |   C |   180 | 17.0 |        
    4066 | 2023-08-19 00:33:51 |      MASTER-Tavrida | (19h 04m 28.83s , +40d 39m 32.6s) |   C |   180 | 18.6 |        
    4157 | 2023-08-19 00:35:22 |   MASTER-Kislovodsk | (19h 03m 25.50s , +40d 51m 05.7s) |  P- |   180 | 17.0 |        
    4337 | 2023-08-19 00:35:22 |   MASTER-Kislovodsk | (19h 03m 25.50s , +40d 51m 05.7s) |  P- |   540 | 17.6 |  Coadd 
    4157 | 2023-08-19 00:35:22 |   MASTER-Kislovodsk | (19h 03m 35.40s , +41d 14m 36.0s) |  P| |   180 | 18.0 |        
    4254 | 2023-08-19 00:36:59 |      MASTER-Tavrida | (19h 04m 28.96s , +40d 37m 36.7s) |   C |   180 | 18.6 |        
    4357 | 2023-08-19 00:38:42 |   MASTER-Kislovodsk | (19h 03m 22.52s , +40d 52m 38.1s) |  P- |   180 | 17.0 |        
    4357 | 2023-08-19 00:38:42 |   MASTER-Kislovodsk | (19h 03m 32.76s , +41d 16m 08.7s) |  P| |   180 | 18.0 |        
    4537 | 2023-08-19 00:38:42 |   MASTER-Kislovodsk | (19h 03m 32.76s , +41d 16m 08.7s) |  P| |   540 | 18.6 |  Coadd 
    4441 | 2023-08-19 00:40:06 |      MASTER-Tavrida | (19h 04m 32.13s , +40d 39m 19.8s) |   C |   180 | 18.5 |        
    4558 | 2023-08-19 00:42:03 |   MASTER-Kislovodsk | (19h 03m 22.46s , +40d 51m 03.8s) |  P- |   180 | 17.1 |        
    4558 | 2023-08-19 00:42:03 |   MASTER-Kislovodsk | (19h 03m 33.07s , +41d 14m 34.4s) |  P| |   180 | 18.0 |        
    4629 | 2023-08-19 00:43:14 |      MASTER-Tavrida | (19h 04m 27.31s , +40d 38m 24.6s) |   C |   180 | 18.5 |        
    4662 | 2023-08-19 00:43:47 |         MASTER-OAFA | (19h 02m 35.32s , +40d 55m 01.3s) |   C |   180 | 17.7 |        
    4758 | 2023-08-19 00:45:23 |   MASTER-Kislovodsk | (19h 03m 25.24s , +40d 52m 27.5s) |  P- |   180 | 17.0 |        
    4938 | 2023-08-19 00:45:23 |   MASTER-Kislovodsk | (19h 03m 25.24s , +40d 52m 27.5s) |  P- |   540 | 17.5 |  Coadd 
    4758 | 2023-08-19 00:45:23 |   MASTER-Kislovodsk | (19h 03m 36.19s , +41d 15m 58.0s) |  P| |   180 | 18.0 |        
    4820 | 2023-08-19 00:46:25 |      MASTER-Tavrida | (19h 04m 26.18s , +40d 39m 19.5s) |   C |   180 | 18.6 |        
    4947 | 2023-08-19 00:48:32 |         MASTER-OAFA | (19h 02m 35.77s , +40d 54m 19.3s) |   C |   180 | 16.8 |        
    4959 | 2023-08-19 00:48:44 |   MASTER-Kislovodsk | (19h 03m 18.30s , +40d 51m 25.8s) |  P- |   180 | 17.0 |        
    4959 | 2023-08-19 00:48:44 |   MASTER-Kislovodsk | (19h 03m 29.69s , +41d 14m 55.6s) |  P| |   180 | 18.0 |        
    5139 | 2023-08-19 00:48:44 |   MASTER-Kislovodsk | (19h 03m 29.69s , +41d 14m 55.6s) |  P| |   540 | 18.4 |  Coadd 
    5007 | 2023-08-19 00:49:32 |      MASTER-Tavrida | (19h 04m 32.82s , +40d 38m 14.5s) |   C |   180 | 18.5 |        
    5195 | 2023-08-19 00:52:39 |      MASTER-Tavrida | (19h 04m 27.62s , +40d 37m 10.2s) |   C |   180 | 18.5 |        
    5360 | 2023-08-19 00:55:25 |   MASTER-Kislovodsk | (19h 03m 24.81s , +40d 51m 11.9s) |  P- |   180 | 16.9 |        
    5360 | 2023-08-19 00:55:25 |   MASTER-Kislovodsk | (19h 03m 36.96s , +41d 14m 41.4s) |  P| |   180 | 17.8 |        
    5385 | 2023-08-19 00:55:50 |      MASTER-Tavrida | (19h 04m 33.92s , +40d 37m 26.2s) |   C |   180 | 18.6 |        
    5560 | 2023-08-19 00:58:45 |   MASTER-Kislovodsk | (19h 03m 17.85s , +40d 50m 03.1s) |  P- |   180 | 17.0 |        
    5740 | 2023-08-19 00:58:45 |   MASTER-Kislovodsk | (19h 03m 17.85s , +40d 50m 03.1s) |  P- |   540 | 17.3 |  Coadd 
    5560 | 2023-08-19 00:58:45 |   MASTER-Kislovodsk | (19h 03m 30.45s , +41d 13m 33.0s) |  P| |   180 | 17.8 |        
    5573 | 2023-08-19 00:58:58 |      MASTER-Tavrida | (19h 04m 30.63s , +40d 38m 50.1s) |   C |   180 | 18.5 |        
    5761 | 2023-08-19 01:02:05 |   MASTER-Kislovodsk | (19h 03m 24.65s , +40d 50m 08.8s) |  P- |   180 | 16.8 |        
    5761 | 2023-08-19 01:02:06 |   MASTER-Kislovodsk | (19h 03m 37.62s , +41d 13m 38.4s) |  P| |   180 | 17.6 |        
    5941 | 2023-08-19 01:02:06 |   MASTER-Kislovodsk | (19h 03m 37.62s , +41d 13m 38.4s) |  P| |   540 | 18.1 |  Coadd 
    5761 | 2023-08-19 01:02:06 |      MASTER-Tavrida | (19h 04m 30.82s , +40d 37m 18.8s) |   C |   180 | 18.5 |        
    5840 | 2023-08-19 01:03:25 |         MASTER-OAFA | (19h 02m 28.43s , +40d 55m 54.7s) |   C |   180 | 17.9 |        
    5949 | 2023-08-19 01:05:14 |      MASTER-Tavrida | (19h 04m 34.73s , +40d 38m 37.4s) |   C |   180 | 18.4 |        
    5961 | 2023-08-19 01:05:26 |   MASTER-Kislovodsk | (19h 03m 21.57s , +40d 51m 24.2s) |  P- |   180 | 16.7 |        
    5961 | 2023-08-19 01:05:26 |   MASTER-Kislovodsk | (19h 03m 34.90s , +41d 14m 54.1s) |  P| |   180 | 17.5 |        
    6082 | 2023-08-19 01:07:26 |         MASTER-OAFA | (19h 02m 34.34s , +40d 54m 53.2s) |   C |   180 | 18.0 |        
    6139 | 2023-08-19 01:08:24 |      MASTER-Tavrida | (19h 04m 28.83s , +40d 37m 45.8s) |   C |   180 | 18.4 |        
    6162 | 2023-08-19 01:08:47 |   MASTER-Kislovodsk | (19h 03m 35.31s , +41d 13m 27.2s) |  P| |   180 | 17.3 |        
    6162 | 2023-08-19 01:08:47 |   MASTER-Kislovodsk | (19h 03m 21.57s , +40d 49m 57.6s) |  P- |   180 | 16.6 |        
    6301 | 2023-08-19 01:11:06 |         MASTER-OAFA | (19h 02m 28.75s , +40d 53m 52.5s) |   C |   180 | 18.0 |        
    6326 | 2023-08-19 01:11:31 |      MASTER-Tavrida | (19h 04m 29.40s , +40d 38m 41.0s) |   C |   180 | 18.4 |        
    6362 | 2023-08-19 01:12:07 |   MASTER-Kislovodsk | (19h 03m 23.15s , +40d 51m 24.1s) |  P- |   180 | 16.2 |        
    6362 | 2023-08-19 01:12:07 |   MASTER-Kislovodsk | (19h 03m 37.34s , +41d 14m 54.1s) |  P| |   180 | 16.9 |        
    6516 | 2023-08-19 01:14:41 |      MASTER-Tavrida | (19h 04m 35.04s , +40d 37m 36.4s) |   C |   180 | 18.2 |        
    6521 | 2023-08-19 01:14:46 |         MASTER-OAFA | (19h 02m 33.90s , +40d 54m 16.7s) |   C |   180 | 18.1 |        
    6563 | 2023-08-19 01:15:27 |   MASTER-Kislovodsk | (19h 03m 17.09s , +40d 50m 26.2s) |  P- |   180 | 16.0 |        
    6563 | 2023-08-19 01:15:28 |   MASTER-Kislovodsk | (19h 03m 31.77s , +41d 13m 56.3s) |  P| |   180 | 16.5 |        
    6707 | 2023-08-19 01:17:52 |      MASTER-Tavrida | (19h 04m 29.10s , +40d 36m 31.7s) |   C |   180 | 18.2 |        
    6897 | 2023-08-19 01:21:02 |      MASTER-Tavrida | (19h 04m 35.81s , +40d 36m 39.4s) |   C |   180 | 18.1 |        
    7088 | 2023-08-19 01:24:13 |      MASTER-Tavrida | (19h 04m 32.58s , +40d 38m 07.9s) |   C |   180 | 18.1 |        
    7276 | 2023-08-19 01:27:20 |      MASTER-Tavrida | (19h 04m 32.71s , +40d 36m 37.4s) |   C |   180 | 17.9 |

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

GCN Circular #34483
A. S. Moskvitin, D. V. Oparin, V. S. Shergin and V. V. Komarov (SAO RAS), report on behalf of the GRB follow-up team.
We observed the field of GRB 230818A (Fermi GBM team, 34478; Tohuvavohu et al., GCN 34479) with the 1-m telescope of SAO RAS Zeiss-1000 equipped with the CCD photometer. We started observations on August 18, 23:32:18 UT (~5 minutes after the trigger) and obtained multiple images in BVRcIc bands (principally in Rc).
We clearly detected the OT (Lipunov et al., GCNs 34476, 34477, 34481, 34482; Gompertz et al., GCN 34480) in our individual frames with the coordinates
```
R. A. (J2000) = 19:03:33.11
Decl. (J2000) = +40:53:49.2 (+/- 0".5)
```
and the following brightness:
```
UT_start   exp, s    t_mid-T0, h   Rmag +/- err
23:32:18    60       0.0872        17.79 +/- 0.06
23:34:00    60       0.1156        18.07 +/- 0.06
23:45:06   120       0.3089        19.18 +/- 0.08
23:57:27   120       0.5147        19.68 +/- 0.10
00:29:01   300       1.0658        20.52 +/- 0.13
00:45:26   2 x 300   1.39333       20.48 +/- 0.09
```
This preliminary photometry is based on nearby USNO-B1 stars (R2 mag), the magnitude is not corrected for MW extinction.
GCN Circular #34484
M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team.
Using 1669 s of XRT Photon Counting mode data and 3 UVOT images for GRB 230818A, 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 = 285.88784, +40.89668 which is equivalent to:
```
RA (J2000): 19h 03m 33.08s
Dec (J2000): +40d 53' 48.0"
```
with an uncertainty of 2.2 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 #34485
D.B. Malesani (Radboud and DAWN/NBI), D. Xu, S.Q. Jiang, T.H. Lu, Z.P. Zhu (NAOC), J.P.U Fynbo (DAWN/NBI), L. Izzo, (INAF-OACN & DAWN/NBI), Z. Gray (NOT) report:
We observed the optical counterpart (Lipunov et al., GCN 34476; Gompertz et al., GCN 34480) of GRB 230818A detected by Fermi/GBM (Fermi/GBM team, GCN 34478) and Swift/BAT (Tohuvavohu et al., GCN 34479), using the 2.56-m Nordic Optical Telescope (NOT) equipped with the ALFOSC camera.
Observations started at 23:53:33 UT on 2023-08-18, i.e., 26 min post-burst, and 2x1200 s spectra were obtained, with a spectral coverage of 3600 - 9500 AA.
The spectrum shows a trace throughout the whole range, with a broad absorption feature at ~ 4150 AA, which can be interpreted as Lya at z~2.4. Redward several prominent absorption features are present, which can be interpreted as due to Si II, O I, C II, Si IV, C IV, Ni II, Fe II at a common redshift of z = 2.42, being consistent with the Lya feature. We thus think this is the redshift of the burst.
After the spectroscopy, an 150 s exposure in the Sloan i-band was obtained. We measured m(i) = 20.02 +/- 0.02 at 1.21 hr post-burst, calibrated with nearby SDSS stars.
GCN Circular #34486
M. H. Siegel (PSU) and A. Tohuvavohu (U. Toronto) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 230818A 144 s after the BAT trigger (Tohuvavohu et al., GCN Circ. 34479). A source consistent with the optical position (Lipunov et al., GCN Circ. 34476) is detected in the initial UVOT exposures.
The preliminary UVOT position is:
```
   RA  (J2000) =  19:03:33.13 = 285.88806 (deg.)
   Dec (J2000) = +40:53:49.0  =  40.89695 (deg.)
```
with an estimated uncertainty of 0.48 arc sec. (radius, 90% confidence).
Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white              144          294          147         19.09 +/- 0.07
v                  379          572           39         18.40 +/- 0.30
b                  477         1513          117         19.68 +/- 0.20
u                  452         1487          117        >19.5
w1                 428         1463           97        >20.2
w2                1026         4987          255        >20.1
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.101 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #34487
N. Pankov (HSE, IKI) A. V. Samokhvalov (citizen scientist, Surgut), A. Pozanenko (IKI), S. Belkin (IKI, HSE) report on behalf of GRB IKI FuN:
We observed the field of GRB 230818A (Swift: Tohuvavohu et al., GCN 34479; Fermi: GBM team, GCN 34478) with 25cm telescope of KGO observatory. Observation started on 2023-08-18 23:42:15, i.e. 14.5 minutes after GRB trigger. The series consist of images with an exposure of 600 s in R-filter. WE clearly detect the afterglow (Lipunov et al., GCN 34476; Gompertz et al., GCN 34480; Moskvitin et al., GCN 34483; Malesani et al., GCN 34485; Siegel et al., GCN 34486). Preliminary photometry of images is following
```
Date UT-start       Exptime Filter t-T0      OT     Err    UL
                    sec            days
2023-08-18 23:42:15 1*600   R      0.013667  18.7   0.2    19.3
2023-08-18 23:52:24 6*600   R      0.038080  19.8   0.3    19.9
```
Ref.stars PanSTARRS-DR1
```
RA Dec r i R(Lupton transformation)
19:03:22.0694 +40:55:31.814 14.1600 14.0074 13.97
19:04:17.2714 +40:50:28.744 14.8986 14.7352 14.71
```
GCN Circular #34488
U.Quadri and L.Strabla (Bassano Bresciano Astronomical Observatory),
Members of: AAVSO - American Association of Variable Star Observers. UAI/SSV - Unione Astrofili Italiani/sezione stelle variabili-GRB. GAC - Gruppo Astrofili Cremonesi.
We imaged the field of GRB 230818A detected by SWIFT(trigger 1186032) with the robotic telescope of (IAU station 565) Bassano Bresciano Observatory, Italy.
The observations started 13.61 min after the GRB trigger, with our Newton automated telescope D=250 mm F/D=4.8.
Weather conditions were good.
We co-added 3 series of 10 exposures of 60 sec each.
We detected afterglow in the error box of the XRTcandidate. (Fermi GBM team, GCN 34478; Tohuvavohu et al., GCN 34479; Ben Gompertz et al., GCN 34480; V. Lipunov et al. GCN 34482; A. S. Moskvitin et al., GCN 34483; D.B. Malesani et al., GCN 34485; N. Pankov et al., GCN 34487) at the following position (+/- 2 arcsec):
```
RA (J2000.0) =  19 03 33.21 
DEC(J2000.0) = +40 53 49.5
```
Our photometry of the afterglow are:
```
Date U.T.            R mag    Sigma
------------------------------------
2023 08 18.99405     18.90    0.07
2023 08 19.00126     19.21    0.07
2023 08 19.00154     19.47    0.06
----------------------------------
```
COMPARISON STARS
```
--------------------------------------------------------------------
   pan-STARRS ID          g           r           i         Rc
--------------------------------------------------------------------
157072858562487290     17.4025     16.7800     16.5376     16.56
157052858895609613     16.8323     16.3279     16.1482     16.13
157072859081709765     15.0561     14.7054     14.5820     14.53
157092859169446573     16.9397     16.4745     16.2972     16.28
157102858906415897     17.0217     16.4894     16.2798     16.28
157062859601321798     15.7561     15.2872     15.0934     15.09
--------------------------------------------------------------------
```
Magnitudes were estimated with the Pan-STARRS cat. Rc mag are derived using Lupton (2005) equations.
Not corrected for galactic dust extinction.
Reference: http://www.osservatoriobassano.org/GRB.asp
The message may be cited.
GCN Circular #34489
S. Dichiara (PSU), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), A.P. Beardmore (U. Leicester), J.P. Osborne (U. Leicester), E. Ambrosi (INAF-IASFPA) , M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR) and P.A. Evans report on behalf of the Swift-XRT team:
We have analysed 6.4 ks of XRT data for GRB 230818A, from 125 s to 40.1 ks after the BAT trigger. The data comprise 41 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 an initial power-law decay with an index of alpha=2.2 (+0.5, -0.4), followed by a break at T+385 s to an alpha of 0.76 (+/-0.06).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.96 (+0.21, -0.20). The best-fitting absorption column is 1.8 (+/-0.7) x 10^21 cm^-2, in excess of the Galactic value of 1.1 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 3.6 x 10^-11 (4.7 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     1.8 (+/-0.7) x 10^21 cm^-2
Galactic foreground: 1.1 x 10^21 cm^-2
Excess significance: 1.8 sigma
Photon index:	     1.96 (+0.21, -0.20)
```
If the light curve continues to decay with a power-law decay index of 0.76, the count rate at T+24 hours will be 0.012 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.3 x 10^-13 (5.7 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/01186032.
This circular is an official product of the Swift-XRT team.
GCN Circular #34490
E. Pavoni and L. Moretti (Leavitt Observatory), 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 observed the field of GRB 230818A (Fermi: GBM team, GCN 34478; Swift: Tohuvavohu et al., GCN 34479; Gompertz et al., GCN 34480; Moskvitin et al., GCN 34483; Malesani et al., GCN 34485; Siegel et al., GCN 34486; Pankov et al., GCN 34487; Quadri et al., GCN 34488) with the telescope of Leavitt Observatory, Italy. Member of:
UAI/SSV - Unione Astrofili Italiani/sezione stelle variabili, GRB section. ATA - Associazione Tuscolana di Astronomia.
The observations began at 00:57 UT on 2023/08/18, 90 min after the GRB trigger, with our RC telescope D=250 mm F/D=8.
Weather conditions were good.
We took 32 images of 120 sec each. All images are V filtered, calibrated with master dark and master flat, stacked with ASTAP software.
We have not detected any clearly visible sources, up to 19.60 magnitude with clear sky at
```
RA (J2000): 19h 03m 33.08s
Dec (J2000): +40d 53' 48.0"
```
on a field of view 31.1 x 26.8 arcmin.
```
Start		End		Vlim
90 min		154 min	19.60
```
The magnitude limit was estimated with nearby stars from the Gaia EDR3 Catalog and is not corrected for galactic dust extinction.
The message may be cited.
GCN Circular #34491
S. Klose, S. Melnikov, B. Stecklum, A. Nicuesa Guelbenzu, F. Ludwig (all TLS Tautenburg) report:
We observed the field of GRB 230818A (Fermi GBM team, GCN 34478; Tohuvavohu et al., GCN 34479) with the Tautenburg 1.34m Schmidt telescope equipped with the TAUKAM 6kx6k CCD camera and using the Sloan filter set.
For the optical transient discovered by Lipunov et al. (GCN 34476) we measure the following magnitudes:
```
g = 19.98 +/- 0.02  (midtime: August 19, 2023,  00:03:14 UT),
r = 19.76 +/- 0.02  (midtime: August 19, 2023,  00:14:43 UT),
i = 19.79 +/- 0.03  (midtime: August 19, 2023,  00:26:00 UT),
```
and
```
g = 21.35 +/- 0.12  (midtime: August 19, 2023,  01:57:48 UT),
r = 20.97 +/- 0.10  (midtime: August 19, 2023,  02:08:35 UT),
i = 20.86 +/- 0.10  (midtime: August 19, 2023,  02:19:32 UT),
```
calibrated against the Pan-STARRS catalog.
GCN Circular #34492
B. Pari (IITB), P. K. Navaneeth (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/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., 2021, JApA, 42, 73) showed the detection of GRB 230818A which was also detected by Fermi-GBM (Fermi GBM Team, GCN Circ. 34478) and Swift-BAT (Tohuvavohu et al., GCN Circ. 34479).
The source was detected in the 20-200 keV energy range in two quadrants. The light curve peaks at 2023-08-18 23:27:37.5 UTC. The measured peak count rate associated with the burst is 96.6 (+28.4, -24.9) counts/s above the background in the combined data of two quadrants, with a total of 372 (+89, -104) counts. The local mean background count rate was 198.2 (+2.1, -3.3) counts/s. Using cumulative rates, we measure a T90 of 6.3 (+2.1, -1.9) s.
The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2023-08-18 23:27:37.3 UTC. The measured peak count rate associated with the burst is 356.8 (+79.6, -44.8) counts/s above the background in the combined data of all quadrants, with a total of 2027 (+489, -526) counts. The local mean background count rate was 1569.3 (+11.3, -12.1) counts/s. We measure a T90 of 10.0 (+3.6, -4.3) s from the cumulative Veto light curve.
CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.
CZTI GRB detections are reported regularly on the payload site at: http://astrosat.iucaa.in/czti/?q=grb
GCN Circular #34493
Mohammad Odeh, Osama Ghannam, Anas Mohammad, and Khalfan Al-Noaimy, report on behalf of Al-Khatim Observatory (AKO) operated by the International Astronomical Center in Abu Dhabi, UAE:
We observed the field of GRB 230818A (Lipunov et al., GCN 34476; Fermi: GBM team, GCN 34478; Swift: Tohuvavohu et al., GCN 34479; Gompertz et al., GCN 34480; Moskvitin et al., GCN 34483; Malesani et al., GCN 34485; Siegel et al., GCN 34486; Pankov et al., GCN 34487; Quadri et al., GCN 34488; Pavoni et al., GCN 34490; Klose et al., GCN 34491) with our 0.36m f/7.7 robotic telescope.
We obtained 13 x 180 sec. images in the clear filter on 19 August, from 16:05 to 17:23 UT, (t_mid - t0 = 17.3 hours) with an upper limit of magnitude = 22.0 for the stacked frames.
We also obtained 15 x 180 sec. images in the Ic filter from 16:02 to 17:32 UT, (t_mid - t0 = 17.35 hours) with an upper limit of magnitude = 20.2 for the stacked frames.
No reliable optical afterglow object was detected.
GCN Circular #34495
A. S. Moskvitin (SAO RAS), V. P. Goranskij (SAI MSU), report on behalf of the GRB follow-up team.
We observed the field of GRB 230818A (Fermi GBM team, GCN 34478; Tohuvavohu et al., GCN 34479) with the 1-m telescope of SAO RAS Zeiss-1000 equipped with the CCD photometer. We obtained 4 x 300 sec. images in Rc band on August 19, 17:42:30--18:07:26 UT.
The OT (Lipunov et al., GCNs 34476, 34477, 34481, 34482; Gompertz et al., GCN 34480; Moskvitin et al., GCN 34483; Malesani et al., GCN 34485; Siegel and Tohuvavohu, GCN 34486; Pankov et al., GCN 34487; Quadri and Strabla, GCN 34488; Klose et al., GCN 34491) is marginally detected with the brightness of R = 23.0 +/- 0.3 (t_mid - t0 = 0.76903 days).
This preliminary photometry is based on nearby USNO-B1 stars (R2 mag). The magnitude of the OT is not corrected for MW extinction.
GCN Circular #34497
A. S. Moskvitin, D. V. Oparin (SAO RAS), A. S. Pozanenko (IKI), report on behalf of the larger GRB follow-up collaboration.
We observed the GRB 230818A OT (Lipunov et al., GCNs 34476, 34477, 34481, 34482; Gompertz et al., GCN 34480; Moskvitin et al., GCN 34483, 34495; Malesani et al., GCN 34485; Siegel and Tohuvavohu, GCN 34486; Pankov et al., GCN 34487; Quadri and Strabla, GCN 34488; Klose et al., GCN 34491) with the BTA 6-meter telescope of SAO RAS equipped with Scorpio-II. The observations were started since ~ 0.5 h after the burst (Fermi: GBM team, GCN 34478; Swift: Tohuvavohu et al., GCN 34479; AstroSat: Pari et al., GCN 34492).
In the 4 x 600 sec spectrum of (4200--8530 AA, FWHM resolution ~ 7A) we identified the absorption lines (C IV, Si II) at a common redshift of z = 2.42. We also identified Si IV and Al II lines at a common redshift of 2.38 which might be an intervening system. Thus we confirm the redshift measurement obtained by Malezani et al. (GCN 34485).
Using acquisition observation we obtained preliminary photometry of the afterglow as following (calibrated against Pan-STARRS nearby stars)
```
Date        UT-start   Exptime   Filter  t-T0      OT        Err
                       sec               days
2023-08-19  00:00:28   2 x 20     r'     0.02339   19.50 +/- 0.02
```
GCN Circular #34498
Neil Pichay, Elma Chuang, WeiKang Zheng and Alex Filippenko (UC Berkeley)
report on behalf of the KAIT GRB team:
We observed the field of GRB 230818A (Fermi GBM team, GCN 34478;
Tohuvavohu et al., GCN 34479) with the 1-m Nickel and 0.76-m KAIT
telescopes located at Lick observatory, California. Observations
started about 0.21 days after the burst. A total of 6 images (600s
exposure each) in R band were taken with Nickel telescopes, while
KAIT images were taken in clear band, with 60s exposure and coadded.
We detected the optical afterglow (Lipunov et al., GCNs 34476, 34477,
34481, 34482; Gompertz et al., GCN 34480; Moskvitin et al., GCN 34483;
Malesani et al., GCN 34485; Siegel and Tohuvavohu, GCN 34486; Pankov
et al., GCN 34487; Quadri and Strabla, GCN 34488; Klose et al., GCN
34491; Moskvitin et al., GCN 34495; 34497) and measure the following
magnitude calibrated to the Pan-STARRS1 catalog:
t-t0(days) filter mag err
0.218 clear 21.8 0.3
0.226 R 21.6 0.2
0.324 clear 21.3 0.3
GCN Circular #34501
P. Veres (UAH), C. Fletcher (USRA) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team:
"At 23:27:35.37 UT on 18 August 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230818A (trigger 714094060/230818977). which was also detected by Swift-BAT (A. Tohuvavohu et al. 2023, GCN 34479) and AstroSat (B. Pari et al. 2023, GCN 34492). The Fermi GBM Final Real-time Localization (GCN 34478) is consistent with the Swift-BAT position.
The angle from the Fermi LAT boresight is 79 degrees.
The GBM light curve consists of a couple peaks with a duration (T90) of about 10 s (50-300 keV). The time-averaged spectrum from T0-1.5 to T0+13.8 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.02 +/- 0.06 and the cutoff energy, parameterized as Epeak, is 260 +/- 30 keV.
The event fluence (10-1000 keV) in this time interval is (5.6 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+0.58 s in the 10-1000 keV band is 10.2 +/- 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 #34511
D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report:
The long GRB 230818A (Swift detection: Tohuvavohu et al., GCN 34479; Fermi GBM observation: Veres et al., GCN 34501) triggered Konus-Wind (KW) at T0=3D84458.443 s UT (23:27:38.443).
The burst light curve shows a single FRED-like pulse which starts at ~T0-0.256 s and has a duration of ~10 s. The emission is seen up to ~2 MeV.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB230818_T84458/
As observed by Konus-Wind, the burst had a total fluence of (4.91 =C2=B1 1.76)x10^-6 erg/cm^2 and a 64-ms peak energy flux, measured from T0, of (3.08 =C2=B1 0.90)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum of the burst (measured from T0 to T0+16.640 s) is best fit in the 20 keV - 15 MeV range by a power law with exponential cutoff (CPL) model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha =3D -1.00(-0.23,+0.27) and Ep =3D 251(-49,+81) keV (chi2 =3D 91/98 dof). Fitting this spectrum by a Band function yields the same values of alpha and Ep, and an upper limit on the high energy photon index beta of -2.5 (chi2 =3D 91/97 dof).
The spectrum near the peak count rate (measured from T0 to T0+0.256 s) is best fit in the 20 keV - 15 MeV range by a CPL model with alpha =3D -0.40(-0.44,+0.56) and Ep =3D 259(-45,+64) keV (chi2 =3D 18/17 dof). Fitting this spectrum by a Band function yields the same values of alpha and Ep, and an upper limit on the high energy photon index beta of -2.7 (chi2 =3D 18/16 dof).
Assuming the redshift z=3D2.42 (Malesani et al., GCN 34485) and a standard cosmology with H_0 =3D 67.3 km/s/Mpc, Omega_M =3D 0.315, and Omega_Lambda =3D 0.685 (Planck Collaboration, 2014), we estimate the burst isotropic energy release E_iso to (6.95 =C2=B1 2.49)x10^52 erg, the isotropic peak luminosity L_iso to (1.49 =C2=B1 0.44)x10^53 erg/s, the rest-frame peak energy of the time-integrated spectrum Ep,i,z to ~860 keV, and the rest-frame peak energy at the peak of the emission Ep,p,z to ~890 keV. With the obtained estimates, GRB 230818A is inside 90% prediction band for the 'Amati' relation and inside 68% prediction band for the 'Yonetoku' relation derived for the sample of >300 long KW GRBs with known redshifts (Tsvetkova et al., 2017; Tsvetkova et al., 2021), see http://www.ioffe.ru/LEA/GRBs/GRB230818_T84458/GRB230818A_rest_frame.pdf
All the quoted errors are estimated at the 68% confidence level. All the presented results are preliminary.
GCN Circular #34514
R. Kumar (IITB), A. Salgundi (IITB), V. Swain (IITB), H. Kumar (IITB), V. Bhalerao (IITB), G.C. Anupama (IIA), S. Barway (IIA) and K. Angail (IAO) report on behalf of the GIT team:
We observed the field of GRB230818A (Lipunov et al., GCN 34476; Fermi GBM team, GCN 34478; Tohuvavohu et al., GCN 34479; Gompertz et al., GCN 34480; Moskvitin et al., GCN 34483; Malesani et al., GCN 34485; Siegel et al., GCN 34486; Pankov et al., GCN 34487; Quadri et al., GCN 34488; Pavoni et al., GCN 34490; Klose et al., GCN 34491; Pari et al., GCN 34492; Odeh et al., GCN 34493; Pichay et al., GCN 34498) with the 0.7m GROWTH-India Telescope (GIT). The observations started at 2023-08-19 15:32:24.081 UT, 0.67 days after the Fermi GBM trigger. We obtained 6 images of 300-sec exposures in the r' filter. We did not detect any new source in our stacked image around R.A.= 19h 03m 33.11s, DEC.=+40d 53m 48.5s. The obtained upper limits follow as:
```
-------------------------------------------------------
JD (mid) | T-T0 (hours) | Filter | Exposure (s) | Limiting Magnitude (AB)
-------------------------------------------------------
2460176.15764106 | 16.326 | r' | 6 x 300 | 21.35
-------------------------------------------------------
```
Our results are consistent with the upper limits reported by AKO (Odeh et al., GCN 34493) and the weak detection by SAO RAS Zeiss-1000 (Moskvitin et al., GCN 34495). 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 #34515
C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU), M. Stamatikos (OSU) (i.e. the Swift-BAT team):
Using the data set from T-60 to T+200 sec from the recent telemetry downlink, we report further analysis of BAT GRB 230818A (trigger #1186032) (Tohuvavohu, et al., GCN Circ. 34479). The BAT ground-calculated position is RA, Dec = 285.888, 40.888 deg which is
```
RA(J2000) = 19h 03m 33.2s
Dec(J2000) = +40d 53' 16.5"
```
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment). The partial coding was 32%.
The mask weighted light curve shows a single fast rise exponential decay peak. T90 (15-350 keV) is 9.82 +- 1.25 sec (estimated error including systematics).
The time-averaged spectrum from T+0.07 to T+12.10 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.36 +- 0.10. The fluence in the 15-150 keV band is 1.9 +- 0.1 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+1.59 sec in the 15-150 keV band is 6.7 +- 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/1186032/BA/
GCN Circular #34523
Chenyu Wang and Zirui Yang report on behalf of the GRID Collaboration:
The long-duration GRB 230818A (Fermi/GBM detection: GCN Circular 34478 and Swift/BAT detection: GCN Circular 34479 ) was observed with GRID-03B.
The detection was confirmed at the trigger time 2023-08-18T23:27:30 UTC. The measured burst duration (T90) in the 30-2000 keV range is approximately 8.75 =C2=B1 1.63 seconds..
GRID is a student-led project to monitor the transient gamma-ray sky with multiple detectors onboard different nanosatellites in the era of multi-messenger astronomy. For more information about GRID, please refer to the following references: https://doi.org/10.1007/s10686-019-09636-w and https://doi.org/10.1007/s10686-021-09819-4.
GCN Circular #34641
S. Giarratana (University of Bologna, INAF-IRA), M. Giroletti (INAF-IRA), G. Ghirlanda (INAF-OAB), N. Di Lalla (Stanford Univ.), N. Omodei (Stanford Univ.)
At 23:33:30 UT on 2023 August 23 (T_mid = 5.02 days post-burst) the Karl G. Jansky VLA observed the field of GRB 230818A (Fermi GBM team, GCN 34478; Tohuvavohu et al., GCN 34479) at a central frequency of 6 and 10 GHz.
The standard J1331+3030 was used as bandpass and flux density calibrator, while J1912+3740 was used as phase calibrator.
From a preliminary analysis, we do not detect the radio counterpart of GRB 230818A. The r.m.s. noise level of the images is 11 uJy/beam and 13 uJy/beam at 6 and 10 GHz, respectively. The synthesized beams are 0.44 x 0.89 arcsec (PA: 81 deg) at 6 GHz and 0.28 x 0.24 arcsec (PA: -70 deg) at 10 GHz.
We would like to thank the staff of the VLA for approving, executing, and processing the observations.
The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.
These observations were carried out as part of project SF161095, approved in the framework of the Fermi - NRAO joint program agreement.
GCN Circular #35506
S. Giarratana (University of Bologna, INAF-IRA), M. Giroletti (INAF-IRA), G. Ghirlanda (INAF-OAB), N. Di Lalla (Stanford Univ.), N. Omodei (Stanford Univ.)
At 22:56:54 UT on 2023 September 18 (T_mid = 31.0 days post-burst) and at 17:12:33 UT on 2023 November 28 (T_mid = 101.8 days post-burst) the Karl G. Jansky VLA started observing the field of GRB 230818A (Fermi GBM team, GCN 34478; Tohuvavohu et al., GCN 34479) at a central frequency of 6 and 10 GHz.
The standard J1331+3030 (3C286) was used as bandpass and flux density calibrator, while J1912+3740 was used as complex gain calibrator.
From a preliminary analysis, we do not detect the radio counterpart of GRB 230818A. We derive the following upper limits (UL; 3sigma).
```
=====================================================
T_mid    Freq     UL     r.m.s.    Beam         PA
[days]   [GHz]   [uJy]   [uJy/b]   [arcsec]     [deg]
=====================================================
31.0     6        24     8         0.34x0.31    -64
31.0     10       24     8         0.22x0.19    -75
101.8    6        30     10        13.2x9.94    -87
101.8    10       24     8         9.05x6.06    -82
=====================================================
```
We would like to thank the staff of the VLA for approving, executing, and processing the observations.
The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.
These observations were carried out as part of project SF161095, approved in the framework of the Fermi - NRAO joint program agreement.

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Jochen Greiner, last update: 09-Jan-2024 [Disclaimer]