Gamma-ray Burst 230328B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN/BACODINE POSITION NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Mar 23 14:55:08 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     1162001,   Seg_Num: 0
GRB_RA:          290.986d {+19h 23m 57s} (J2000),
                 290.595d {+19h 22m 23s} (current),
                 291.810d {+19h 27m 14s} (1950)
GRB_DEC:         +80.016d {+80d 00' 58"} (J2000),
                 +80.062d {+80d 03' 44"} (current),
                 +79.915d {+79d 54' 53"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       3774 [cnts]    Image_Peak=489 [image_cnts]
TRIGGER_DUR:     1.024 [sec] 
TRIGGER_INDEX:   146     E_range: 25-100 keV
BKG_INTEN:       11946 [cnts]
BKG_TIME:        53672.99 SOD {14:54:32.99} UT
BKG_DUR:         8 [sec]
GRB_DATE:        20031 TJD;    87 DOY;   23/03/28
GRB_TIME:        53688.54 SOD {14:54:48.54} UT
GRB_PHI:         -147.34 [deg]
GRB_THETA:        37.35 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     53.78 [sigma]
IMAGE_SIGNIF:    17.77 [sigma]
MERIT_PARAMS:     +1  +0  +0  +0  +2  +5  +0  +0  -9  +0 
SUN_POSTN:         7.05d {+00h 28m 11s}   +3.04d {+03d 02' 38"}
SUN_DIST:         84.68 [deg]   Sun_angle= 5.1 [hr] (West of Sun)
MOON_POSTN:       92.64d {+06h 10m 33s}  +27.87d {+27d 51' 56"}
MOON_DIST:        71.62 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      111.99, 25.29 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       75.68, 75.46 [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 = 201.44,13.78 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(1.0<100sec) coincident with the FERMI_GBM event (trignum=701708092).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Tue 28 Mar 23 14:55:26 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      60
TRIGGER_NUM:     701708092
GRB_RA:          309.483d {+20h 37m 56s} (J2000),
                 309.551d {+20h 38m 12s} (current),
                 309.336d {+20h 37m 21s} (1950)
GRB_DEC:         +66.517d {+66d 31' 00"} (J2000),
                 +66.599d {+66d 35' 56"} (current),
                 +66.340d {+66d 20' 24"} (1950)
GRB_ERROR:       7.13 [deg radius, statistical plus systematic]
GRB_INTEN:       368 [cnts/sec]
DATA_SIGNIF:     35.40 [sigma]
INTEG_TIME:      4.096 [sec]
GRB_DATE:        20031 TJD;    87 DOY;   23/03/28
GRB_TIME:        53687.43 SOD {14:54:47.43} UT
GRB_PHI:         220.00 [deg]
GRB_THETA:        35.00 [deg]
DATA_TIME_SCALE: 4.0960 [sec]
HARD_RATIO:      1.22
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      98%  GRB
2nd_MOST_LIKELY:   1%  Generic SGR
DETECTORS:       0,0,0, 0,0,0, 0,1,0, 0,0,1, 0,0,
SUN_POSTN:         7.05d {+00h 28m 11s}   +3.04d {+03d 02' 39"}
SUN_DIST:         74.82 [deg]   Sun_angle= 3.8 [hr] (West of Sun)
MOON_POSTN:       92.64d {+06h 10m 34s}  +27.87d {+27d 51' 57"}
MOON_DIST:        81.48 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      101.29, 15.03 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       18.07, 74.54 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230328621/quicklook/glg_lc_medres34_bn230328621.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 348.72,4.90 [deg].  
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=1162001).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Tue 28 Mar 23 14:55:17 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      48
TRIGGER_NUM:     701708092
GRB_RA:          293.817d {+19h 35m 16s} (J2000),
                 293.610d {+19h 34m 26s} (current),
                 294.253d {+19h 37m 01s} (1950)
GRB_DEC:         +76.767d {+76d 46' 00"} (J2000),
                 +76.819d {+76d 49' 07"} (current),
                 +76.653d {+76d 39' 12"} (1950)
GRB_ERROR:       12.83 [deg radius, statistical plus systematic]
GRB_INTEN:       347 [cnts/sec]
DATA_SIGNIF:     12.40 [sigma]
INTEG_TIME:      0.512 [sec]
GRB_DATE:        20031 TJD;    87 DOY;   23/03/28
GRB_TIME:        53687.43 SOD {14:54:47.43} UT
GRB_PHI:         203.00 [deg]
GRB_THETA:        40.00 [deg]
DATA_TIME_SCALE: 0.5120 [sec]
HARD_RATIO:      1.02
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      97%  GRB
2nd_MOST_LIKELY:   1%  Generic SGR
DETECTORS:       0,0,0, 0,0,0, 0,1,0, 0,0,1, 0,0,
SUN_POSTN:         7.05d {+00h 28m 11s}   +3.04d {+03d 02' 39"}
SUN_DIST:         83.30 [deg]   Sun_angle= 4.9 [hr] (West of Sun)
MOON_POSTN:       92.64d {+06h 10m 33s}  +27.87d {+27d 51' 57"}
MOON_DIST:        74.52 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      108.70, 23.90 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       64.65, 77.53 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230328621/quicklook/glg_lc_medres34_bn230328621.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 348.72,4.90 [deg].  
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=1162001).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Tue 28 Mar 23 14:55:36 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      59
TRIGGER_NUM:     701708092
GRB_RA:          301.880d {+20h 07m 31s} (J2000),
                 301.752d {+20h 07m 00s} (current),
                 302.147d {+20h 08m 35s} (1950)
GRB_DEC:         +75.490d {+75d 29' 24"} (J2000),
                 +75.558d {+75d 33' 30"} (current),
                 +75.342d {+75d 20' 33"} (1950)
GRB_ERROR:       3.56 [deg radius, statistical only]
DATA_SIGNIF:     35.40 [sigma]
DATA_INTERVAL:   2.048 [sec]
GRB_DATE:        20031 TJD;    87 DOY;   23/03/28
GRB_TIME:        53687.43 SOD {14:54:47.43} UT
GRB_PHI:         205.00 [deg]
GRB_THETA:        38.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4173 (Gnd S/W Version number)
SUN_POSTN:         7.05d {+00h 28m 12s}   +3.04d {+03d 02' 39"}
SUN_DIST:         81.05 [deg]   Sun_angle= 4.4 [hr] (West of Sun)
MOON_POSTN:       92.64d {+06h 10m 34s}  +27.87d {+27d 51' 57"}
MOON_DIST:        74.93 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      108.17, 21.64 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       55.13, 76.62 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230328621/quicklook/glg_lc_medres34_bn230328621.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_701708092.fits
COMMENTS:        Fermi-GBM Ground-calculated Coordinates.  
COMMENTS:        In the LAT Field-of-view.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file will not be created/available until ~15 min after the trigger.  
COMMENTS:        The POS_MAP_URL file will not be created/available until ~1.5 min after the notice.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(1.0<100sec) coincident with the SWIFT_BAT event (trignum=1162001).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Tue 28 Mar 23 15:04:07 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     701708092
GRB_RA:          301.820d {+20h 07m 17s} (J2000),
                 301.689d {+20h 06m 45s} (current),
                 302.094d {+20h 08m 23s} (1950)
GRB_DEC:         +75.590d {+75d 35' 24"} (J2000),
                 +75.658d {+75d 39' 29"} (current),
                 +75.443d {+75d 26' 33"} (1950)
GRB_ERROR:       3.21 [deg radius, statistical only]
GRB_DATE:        20031 TJD;    87 DOY;   23/03/28
GRB_TIME:        53687.43 SOD {14:54:47.43} UT
GRB_PHI:         205.00 [deg]
GRB_THETA:        38.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:         7.05d {+00h 28m 13s}   +3.05d {+03d 02' 47"}
SUN_DIST:         81.11 [deg]   Sun_angle= 4.4 [hr] (West of Sun)
MOON_POSTN:       92.72d {+06h 10m 53s}  +27.87d {+27d 52' 05"}
MOON_DIST:        74.85 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      108.26, 21.70 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       55.55, 76.59 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230328621/quicklook/glg_lc_medres34_bn230328621.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230328621/quicklook/glg_locplot_all_bn230328621.png
COMMENTS:        Fermi-GBM Final Position.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        The LC_URL file should be available by the time this FINAL notice is produced.  
COMMENTS:        This notice was generated completely by automated pipeline processing.  
COMMENTS:        In the LAT Field-of-view.  
COMMENTS:        This is likely a Long GRB.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(1.0<100sec) coincident with the SWIFT_BAT event (trignum=1162001).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Mar 23 14:56:50 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     1162001,   Seg_Num: 0
POINT_RA:        290.877d {+19h 23m 30s} (J2000)
POINT_DEC:       +80.023d {+80d 01' 22"} (J2000)
IMG_START_DATE:  20031 TJD;    87 DOY;   23/03/28
IMG_START_TIME:  53798.87 SOD {14:56:38.87} UT,   110.3 [sec] since BAT Trigger Time
COUNTS:          9    Min_needed= 20
STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
PH2_ITER:        1    Max_iter_allowed= 4
ERROR_CODE:      1
COMMENTS:        SWIFT-XRT Nack Position.  
COMMENTS:        No source found in the image.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Mar 23 14:58:25 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     1162001,   Seg_Num: 0
GRB_RA:          290.986d {+19h 23m 57s} (J2000),
                 290.595d {+19h 22m 23s} (current),
                 291.810d {+19h 27m 14s} (1950)
GRB_DEC:         +80.016d {+80d 00' 58"} (J2000),
                 +80.062d {+80d 03' 44"} (current),
                 +79.915d {+79d 54' 53"} (1950)
GRB_DATE:        20031 TJD;    87 DOY;   23/03/28
GRB_TIME:        53688.54 SOD {14:54:48.54} UT
TRIGGER_INDEX:   146
GRB_PHI:         -147.34 [deg]
GRB_THETA:        37.35 [deg]
DELTA_TIME:      45.00 [sec]
TRIGGER_DUR:     1.024 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     53.78 [sigma]
IMAGE_SIGNIF:    17.77 [sigma]
LC_URL:          sw01162001000msb.lc
SUN_POSTN:         7.05d {+00h 28m 12s}   +3.04d {+03d 02' 42"}
SUN_DIST:         84.68 [deg]   Sun_angle= 5.1 [hr] (West of Sun)
MOON_POSTN:       92.67d {+06h 10m 40s}  +27.87d {+27d 51' 59"}
MOON_DIST:        71.62 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      111.99, 25.29 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       75.68, 75.46 [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 = 201.44,13.78 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Mar 23 14:59:31 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1162001,   Seg_Num: 0
POINT_RA:        290.877d {+19h 23m 31s} (J2000)
POINT_DEC:       +80.023d {+80d 01' 22"} (J2000)
POINT_ROLL:      103.094d
IMG_START_DATE:  20031 TJD;    87 DOY;   23/03/28
IMG_START_TIME:  53802.63 SOD {14:56:42.63} UT,   114.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.611
N_STARS:         38
X_OFFSET:        609 [pixels]
Y_OFFSET:        490 [pixels]
X_MAX:           1568 [pixels]
Y_MAX:           1449 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw01162001000msufc0114.fits
SUN_POSTN:         7.05d {+00h 28m 12s}   +3.05d {+03d 02' 43"}
SUN_DIST:         84.70 [deg]   Sun_angle= 5.1 [hr] (West of Sun)
MOON_POSTN:       92.68d {+06h 10m 43s}  +27.87d {+27d 52' 00"}
MOON_DIST:        71.62 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      111.99, 25.31 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       75.76, 75.47 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Mar 23 14:59:49 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1162001,   Seg_Num: 0
POINT_RA:        290.877d {+19h 23m 31s} (J2000)
POINT_DEC:       +80.023d {+80d 01' 22"} (J2000)
POINT_ROLL:      103.094d
IMG_START_DATE:  20031 TJD;    87 DOY;   23/03/28
IMG_START_TIME:  53802.63 SOD {14:56:42.63} UT,   114.1 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        1.611
N_STARS:         38
X_OFFSET:        609 [pixels]
Y_OFFSET:        490 [pixels]
X_MAX:           1568 [pixels]
Y_MAX:           1449 [pixels]
DET_THRESH:      11
PHOTO_THRESH:    5
SL_URL:          sw01162001000msufc0114.fits
SUN_POSTN:         7.05d {+00h 28m 12s}   +3.05d {+03d 02' 43"}
SUN_DIST:         84.70 [deg]   Sun_angle= 5.1 [hr] (West of Sun)
MOON_POSTN:       92.68d {+06h 10m 44s}  +27.87d {+27d 52' 01"}
MOON_DIST:        71.62 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      111.99, 25.31 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       75.76, 75.47 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Mar 23 15:00:59 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1162001,   Seg_Num: 0
POINT_RA:        290.877d {+19h 23m 31s} (J2000)
POINT_DEC:       +80.023d {+80d 01' 22"} (J2000)
ROLL:            103.094d
IMG_START_DATE:  20031 TJD;    87 DOY;   23/03/28
IMG_START_TIME:  53802.63 SOD {14:56:42.63} UT,   114.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     701708233
X_OFFSET:        928 [pixels]
Y_OFFSET:        809 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1088
Y_GRB_POS:       969
BINNING_INDEX:   1
IM_URL:          sw01162001000msuni0146.fits
SUN_POSTN:         7.05d {+00h 28m 12s}   +3.05d {+03d 02' 44"}
SUN_DIST:         84.70 [deg]   Sun_angle= 5.1 [hr] (West of Sun)
MOON_POSTN:       92.69d {+06h 10m 46s}  +27.87d {+27d 52' 02"}
MOON_DIST:        71.62 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      111.99, 25.31 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       75.76, 75.47 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Mar 23 15:01:05 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1162001,   Seg_Num: 0
POINT_RA:        290.877d {+19h 23m 31s} (J2000)
POINT_DEC:       +80.023d {+80d 01' 22"} (J2000)
ROLL:            103.094d
IMG_START_DATE:  20031 TJD;    87 DOY;   23/03/28
IMG_START_TIME:  53802.63 SOD {14:56:42.63} UT,   114.1 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     701708233
X_OFFSET:        928 [pixels]
Y_OFFSET:        809 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1088
Y_GRB_POS:       969
BINNING_INDEX:   1
IM_URL:          sw01162001000msuni0146.fits
SUN_POSTN:         7.05d {+00h 28m 12s}   +3.05d {+03d 02' 44"}
SUN_DIST:         84.70 [deg]   Sun_angle= 5.1 [hr] (West of Sun)
MOON_POSTN:       92.69d {+06h 10m 46s}  +27.87d {+27d 52' 02"}
MOON_DIST:        71.62 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      111.99, 25.31 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       75.76, 75.47 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Mar 23 15:00:53 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     1162001,   Seg_Num: 0
GRB_RA:          291.0080d {+19h 24m 01.91s} (J2000),
                 290.6177d {+19h 22m 28.23s} (current),
                 291.8311d {+19h 27m 19.47s} (1950)
GRB_DEC:         +80.0097d {+80d 00' 34.9"} (J2000),
                 +80.0557d {+80d 03' 20.4"} (current),
                 +79.9080d {+79d 54' 28.8"} (1950)
GRB_ERROR:       3.5 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  20031 TJD;    87 DOY;   23/03/28
IMG_START_TIME:  53812.00 SOD {14:56:52.00} UT,   123.5 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:         7.05d {+00h 28m 12s}   +3.05d {+03d 02' 44"}
SUN_DIST:         84.68 [deg]   Sun_angle= 5.1 [hr] (West of Sun)
MOON_POSTN:       92.69d {+06h 10m 46s}  +27.87d {+27d 52' 02"}
MOON_DIST:        71.63 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      111.98, 25.29 [deg] galactic lon,lat of the burst
ECL_COORDS:       75.65, 75.46 [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 #33526
The Fermi GBM team reports the detection of a likely LONG GRB
At 14:54:47 UT on 28 Mar 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230328B (trigger 701708092.430074 / 230328621).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 301.8, Dec = 75.6 (J2000 degrees, equivalent to J2000 20h 07m, 75d 35'), with a statistical uncertainty of 3.2 degrees.
The angle from the Fermi LAT boresight is 38.0 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230328621/quicklook/glg_skymap_all_bn230328621.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/bn230328621/quicklook/glg_healpix_all_bn230328621.fit
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230328621/quicklook/glg_lc_medres34_bn230328621.gif

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Mar 23 15:08:21 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1162001,   Seg_Num: 0
POINT_RA:        290.872d {+19h 23m 29s} (J2000)
POINT_DEC:       +80.022d {+80d 01' 18"} (J2000)
POINT_ROLL:      103.088d
IMG_START_DATE:  20031 TJD;    87 DOY;   23/03/28
IMG_START_TIME:  54014.84 SOD {15:00:14.84} UT,   326.3 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.776
N_STARS:         128
X_OFFSET:        369 [pixels]
Y_OFFSET:        250 [pixels]
X_MAX:           1808 [pixels]
Y_MAX:           1689 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    3
SL_URL:          sw01162001000msufc0326.fits
SUN_POSTN:         7.06d {+00h 28m 13s}   +3.05d {+03d 02' 51"}
SUN_DIST:         84.70 [deg]   Sun_angle= 5.1 [hr] (West of Sun)
MOON_POSTN:       92.76d {+06h 11m 03s}  +27.87d {+27d 52' 08"}
MOON_DIST:        71.63 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      111.99, 25.31 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       75.76, 75.47 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN Circular #33527
J.D. Gropp (PSU), S. Dichiara (PSU), R. A. J. Eyles-Ferris (U Leicester), N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC), M. J. Moss (GWU), K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift Observatory Team:
At 14:54:48 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 230328B (trigger=1162001). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 290.986, +80.016 which is
```
   RA(J2000) = 19h 23m 57s
   Dec(J2000) = +80d 00' 58"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex GRB structure with a duration of about 20 sec, followed by a bright flaring afterglow visible below 25 keV for at least 200 s. The peak count rate was ~4375 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 14:56:38.8 UT, 110.3 seconds after the BAT trigger. Using promptly downlinked data we find a fading, uncatalogued X-ray source located at RA, Dec 291.00418, 80.00951 which is equivalent to:
```
   RA(J2000)  = 19h 24m 01.00s
   Dec(J2000) = +80d 00' 34.2"
```
with an uncertainty of 3.6 arcseconds (radius, 90% containment). This location is 25 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at https://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (6.28 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 3.6 (+1.76/-1.56) x 10^21 cm^-2 (90% confidence).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 114 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at
```
  RA(J2000)  =	19:24:01.84 = 291.00765
  DEC(J2000) = +80:00:34.5  =  80.00959
```
with a 90%-confidence error radius of about 0.62 arc sec. This position is 0.7 arc sec. from the center of the XRT error circle. The estimated magnitude is 18.22 with a 1-sigma error of about 0.15. No correction has been made for the expected extinction corresponding to E(B-V) of 0.070.
Burst Advocate for this burst is J.D. Gropp (jdg44 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:     Tue 28 Mar 23 15:08:37 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1162001,   Seg_Num: 0
POINT_RA:        290.872d {+19h 23m 29s} (J2000)
POINT_DEC:       +80.022d {+80d 01' 18"} (J2000)
POINT_ROLL:      103.088d
IMG_START_DATE:  20031 TJD;    87 DOY;   23/03/28
IMG_START_TIME:  54014.84 SOD {15:00:14.84} UT,   326.3 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        0.776
N_STARS:         128
X_OFFSET:        369 [pixels]
Y_OFFSET:        250 [pixels]
X_MAX:           1808 [pixels]
Y_MAX:           1689 [pixels]
DET_THRESH:      8
PHOTO_THRESH:    3
SL_URL:          sw01162001000msufc0326.fits
SUN_POSTN:         7.06d {+00h 28m 13s}   +3.05d {+03d 02' 52"}
SUN_DIST:         84.70 [deg]   Sun_angle= 5.1 [hr] (West of Sun)
MOON_POSTN:       92.76d {+06h 11m 04s}  +27.87d {+27d 52' 08"}
MOON_DIST:        71.63 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      111.99, 25.31 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       75.76, 75.47 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Mar 23 15:09:37 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1162001,   Seg_Num: 0
POINT_RA:        290.872d {+19h 23m 29s} (J2000)
POINT_DEC:       +80.022d {+80d 01' 18"} (J2000)
ROLL:            103.088d
IMG_START_DATE:  20031 TJD;    87 DOY;   23/03/28
IMG_START_TIME:  54014.84 SOD {15:00:14.84} UT,   326.3 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     701708445
X_OFFSET:        928 [pixels]
Y_OFFSET:        809 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1088
Y_GRB_POS:       969
BINNING_INDEX:   1
IM_URL:          sw01162001000msuni0358.fits
SUN_POSTN:         7.06d {+00h 28m 14s}   +3.05d {+03d 02' 53"}
SUN_DIST:         84.70 [deg]   Sun_angle= 5.1 [hr] (West of Sun)
MOON_POSTN:       92.77d {+06h 11m 06s}  +27.87d {+27d 52' 09"}
MOON_DIST:        71.63 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      111.99, 25.31 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       75.76, 75.47 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Mar 23 15:09:44 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     1162001,   Seg_Num: 0
GRB_RA:          291.0041d {+19h 24m 00.98s} (J2000),
                 290.6137d {+19h 22m 27.29s} (current),
                 291.8273d {+19h 27m 18.54s} (1950)
GRB_DEC:         +80.0097d {+80d 00' 34.9"} (J2000),
                 +80.0557d {+80d 03' 20.3"} (current),
                 +79.9080d {+79d 54' 28.8"} (1950)
GRB_ERROR:       1.9 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  20031 TJD;    87 DOY;   23/03/28
IMG_START_TIME:  53812.00 SOD {14:56:52.00} UT,   123.5 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:         7.06d {+00h 28m 14s}   +3.05d {+03d 02' 53"}
SUN_DIST:         84.68 [deg]   Sun_angle= 5.1 [hr] (West of Sun)
MOON_POSTN:       92.78d {+06h 11m 06s}  +27.87d {+27d 52' 09"}
MOON_DIST:        71.63 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      111.98, 25.29 [deg] galactic lon,lat of the burst
ECL_COORDS:       75.66, 75.46 [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:        This position was enhanced using UVOT field astrometry.  
COMMENTS:        The probability that this is a serendipitous source in the  
COMMENTS:        SPER window is 0.58% < P(seren) < 1.1%.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Mar 23 15:13:36 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1162001,   Seg_Num: 0
POINT_RA:        290.872d {+19h 23m 29s} (J2000)
POINT_DEC:       +80.022d {+80d 01' 19"} (J2000)
POINT_ROLL:      103.088d
IMG_START_DATE:  20031 TJD;    87 DOY;   23/03/28
IMG_START_TIME:  54545.25 SOD {15:09:05.25} UT,   856.7 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        0.645
N_STARS:         62
X_OFFSET:        369 [pixels]
Y_OFFSET:        250 [pixels]
X_MAX:           1808 [pixels]
Y_MAX:           1689 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw01162001000msufc0856.fits
SUN_POSTN:         7.06d {+00h 28m 14s}   +3.05d {+03d 02' 56"}
SUN_DIST:         84.70 [deg]   Sun_angle= 5.1 [hr] (West of Sun)
MOON_POSTN:       92.81d {+06h 11m 15s}  +27.87d {+27d 52' 13"}
MOON_DIST:        71.63 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      111.99, 25.31 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       75.76, 75.47 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Mar 23 15:13:45 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1162001,   Seg_Num: 0
POINT_RA:        290.872d {+19h 23m 29s} (J2000)
POINT_DEC:       +80.022d {+80d 01' 19"} (J2000)
POINT_ROLL:      103.088d
IMG_START_DATE:  20031 TJD;    87 DOY;   23/03/28
IMG_START_TIME:  54545.25 SOD {15:09:05.25} UT,   856.7 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        0.645
N_STARS:         62
X_OFFSET:        369 [pixels]
Y_OFFSET:        250 [pixels]
X_MAX:           1808 [pixels]
Y_MAX:           1689 [pixels]
DET_THRESH:      7
PHOTO_THRESH:    3
SL_URL:          sw01162001000msufc0856.fits
SUN_POSTN:         7.06d {+00h 28m 14s}   +3.05d {+03d 02' 57"}
SUN_DIST:         84.70 [deg]   Sun_angle= 5.1 [hr] (West of Sun)
MOON_POSTN:       92.81d {+06h 11m 15s}  +27.87d {+27d 52' 13"}
MOON_DIST:        71.63 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      111.99, 25.31 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       75.76, 75.47 [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:     Tue 28 Mar 23 15:14:33 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1162001,   Seg_Num: 0
POINT_RA:        290.872d {+19h 23m 29s} (J2000)
POINT_DEC:       +80.022d {+80d 01' 19"} (J2000)
ROLL:            103.088d
IMG_START_DATE:  20031 TJD;    87 DOY;   23/03/28
IMG_START_TIME:  54545.25 SOD {15:09:05.25} UT,   856.7 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     701708976
X_OFFSET:        928 [pixels]
Y_OFFSET:        809 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1088
Y_GRB_POS:       969
BINNING_INDEX:   1
IM_URL:          sw01162001000msuni0888.fits
SUN_POSTN:         7.06d {+00h 28m 14s}   +3.05d {+03d 02' 57"}
SUN_DIST:         84.70 [deg]   Sun_angle= 5.1 [hr] (West of Sun)
MOON_POSTN:       92.82d {+06h 11m 17s}  +27.87d {+27d 52' 14"}
MOON_DIST:        71.63 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      111.99, 25.31 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       75.76, 75.47 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Mar 23 15:14:40 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1162001,   Seg_Num: 0
POINT_RA:        290.872d {+19h 23m 29s} (J2000)
POINT_DEC:       +80.022d {+80d 01' 19"} (J2000)
ROLL:            103.088d
IMG_START_DATE:  20031 TJD;    87 DOY;   23/03/28
IMG_START_TIME:  54545.25 SOD {15:09:05.25} UT,   856.7 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     701708976
X_OFFSET:        928 [pixels]
Y_OFFSET:        809 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1088
Y_GRB_POS:       969
BINNING_INDEX:   1
IM_URL:          sw01162001000msuni0888.fits
SUN_POSTN:         7.06d {+00h 28m 14s}   +3.05d {+03d 02' 57"}
SUN_DIST:         84.70 [deg]   Sun_angle= 5.1 [hr] (West of Sun)
MOON_POSTN:       92.82d {+06h 11m 17s}  +27.87d {+27d 52' 14"}
MOON_DIST:        71.63 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      111.99, 25.31 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       75.76, 75.47 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        If you have elected to receive attachments:  
COMMENTS:        The uvot_catalog_image.fits.gz file does not exist; skipping the attachment.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Mar 23 15:09:43 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1162001,   Seg_Num: 0
POINT_RA:        290.872d {+19h 23m 29s} (J2000)
POINT_DEC:       +80.022d {+80d 01' 18"} (J2000)
ROLL:            103.088d
IMG_START_DATE:  20031 TJD;    87 DOY;   23/03/28
IMG_START_TIME:  54014.84 SOD {15:00:14.84} UT,   326.3 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     701708445
X_OFFSET:        928 [pixels]
Y_OFFSET:        809 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1088
Y_GRB_POS:       969
BINNING_INDEX:   1
IM_URL:          sw01162001000msuni0358.fits
SUN_POSTN:         7.06d {+00h 28m 14s}   +3.05d {+03d 02' 53"}
SUN_DIST:         84.70 [deg]   Sun_angle= 5.1 [hr] (West of Sun)
MOON_POSTN:       92.78d {+06h 11m 06s}  +27.87d {+27d 52' 09"}
MOON_DIST:        71.63 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      111.99, 25.31 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:       75.76, 75.47 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Image.  
COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
COMMENTS:        The image has 2x2 binning (compression).  
COMMENTS:        All 4 attachments are included.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Tue 28 Mar 23 15:03:28 UT
NOTICE_TYPE:     Swift-UVOT Position
TRIGGER_NUM:     1162001,   Seg_Num: 0
GRB_RA:          291.0076d {+19h 24m 01.82s} (J2000),
                 290.6173d {+19h 22m 28.14s} (current),
                 291.8307d {+19h 27m 19.36s} (1950)
GRB_DEC:         +80.0095d {+80d 00' 34.2"} (J2000),
                 +80.0555d {+80d 03' 19.6"} (current),
                 +79.9078d {+79d 54' 28.0"} (1950)
GRB_ERROR:       0.6 [arcsec radius, statistical only]
GRB_MAG:         18.21 +/- 0.14 [mag]
FILTER:          10, White
IMG_START_DATE:  20031 TJD;    87 DOY;   23/03/28
IMG_START_TIME:  53799.00 SOD {14:56:39.00} UT,   110.5 [sec] since BAT Trigger Time
SUN_POSTN:         7.05d {+00h 28m 13s}   +3.05d {+03d 02' 47"}
SUN_DIST:         84.68 [deg]   Sun_angle= 5.1 [hr] (West of Sun)
MOON_POSTN:       92.72d {+06h 10m 52s}  +27.87d {+27d 52' 04"}
MOON_DIST:        71.63 [deg]
MOON_ILLUM:      46 [%]
GAL_COORDS:      111.98, 25.29 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       75.65, 75.46 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS:        SWIFT UVOT Position Notice.  
COMMENTS:        This Notice was ground-generated -- not flight-generated.  
COMMENTS:        Result based on Genie data.  
COMMENTS:        Notice generated automatically.

GCN Circular #33528
N. Pankov (HSE), E. Klunko (ISTP), A. Pozanenko (IKI), S. Belkin (IKI) report on behalf of GRB IKI FuN:
We observed the field of Swift GRB 230328B (Gropp et al. GCN 33527) with AZT-33IK telescope of Mondy observatory in R-filter on 2023-03-28 starting (UT) 15:27:18. We clearly detect the optical afterglow of GRB 230328B (Gropp et al. GCN 33527) at the position of (J2000) 19 24 01.828 +80 00 34.53 with an error of 0.5 arcsec in both coordinates, which coincides with the position of UVOT (Gropp et al. GCN 33527).
Preliminary photometry of a stack of the first 5 images is following
```
Date       UT start  t-T0     Exp.  Filter   OT     Err.  UL(3sigma)
                    (mid, days)  (s)

2023-03-28  15:27:18   0.026047 5*60 R        18.9  0.2   21.1
```
The photometry is based on nearby USNO-B1.0 stars.
GCN Circular #33529
J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team.
Using 1128 s of XRT Photon Counting mode data and 3 UVOT images for GRB 230328B, 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 = 291.00713, +80.00952 which is equivalent to:
```
RA (J2000): 19h 24m 1.71s
Dec (J2000): +80d 00' 34.3"
```
with an uncertainty of 2.1 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 #33530
S. Belkin (IKI), R. Ya. Inasaridze (AbAO), E. Klunko (ISTP), A. Novichonok (Petrozavodsk State University, KIAM), A. Pozanenko (IKI), N. Pankov (HSE, IKI), D. Datashvili (AbAO), V. R. Ayvazian (AbAO), G. V. Kapanadze (AbAO) report on behalf of GRB IKI FuN:
We observed the field of Swift GRB 230328B (Gropp et al. GCN 33527; Osborne et al. GCN 33529) till now with AZT-33IK telescope of Mondy observatory in R-filter, RC-36 telescope of Kitab observatory in Clear, AS-32 telescope of Abastumani observatory in R-filter. The optical afterglow (Gropp et al. GCN 33527; Pankov et al. GCN 33528) is detected in Mondy and Abastumani, and not detected in Kitab observatory.
Preliminary photometry of a stacked images is following
```
Date       UT start   t-T0    Filter Exp.    OT    Err.  UL(3sigma)
                       (mid, days)    (s)

2023-03-28  16:19:20  0.062188  R      5*120    19.34  0.10   21.0
2023-03-28  16:37:07  0.042338  Clear 19*60     n/d    n/d    17.6
2023-03-28  16:15:48  0.086725  R    104*60     19.50  0.10   21.2
```
The photometry is based on nearby USNO-B1.0 stars.
Approximation of above photometry in R-filter and photometry reported early (GCN 33528) results in the power law index of -0.45 of slow decay LC of GRB 230328B.
GCN Circular #33531
S. Dalessi (UAH) and C. Meegan (UAH) report on behalf of the Fermi GBM Team:
"At 14:54:47.43 UT on 28 March 2023, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 230328B (trigger 701708092 / 230328621), which was also detected by the Swift/BAT (J.D. Gropp et al. 2023, GCN 33527) The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM trigger time is 38 degrees.
The GBM light curve consists of a single burst with a duration (T90) of about 19 s (50-300 keV). The time-averaged spectrum from T0-3.5 s to T0+19.1 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.16 +/- 0.03 and the cutoff energy, parameterized as Epeak, is 169.6 +/- 9.9 keV.
The event fluence (10-1000 keV) in this time interval is (9.4 +/- 0.3)E-06 erg/cm^2. The 1 sec peak photon flux measured starting from T0+1.4 s in the 10-1000 keV band is 12.7 +/- 0.3 ph/s/cm^2.
A Band function fits the spectrum equally well with Epeak = 125.0 +/- 11.3 keV, alpha = -1.03 +/- 0.06, and beta = -2.10+/- 0.09.
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 #33532
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 230328B which was also detected by Fermi-GBM (GCN Circ. 33526), Swift-BAT (Gropp et. al, GCN Circ. 33527).
The source was clearly detected in the 20-200 keV energy range. The light curve peaks at 2023-03-28 14:54:49.5 UTC. The measured peak count rate associated with the burst is 244.7 (+41.3 -43.3) counts/s above the background in the combined data of all quadrants, with a total of 1090 (+249 -250) counts. The local mean background count rate was 409.1 (+2.4 -3.1) counts/s. Using cumulative rates, we measure a T90 of 11.78 (+4.17 -4.51) s.
It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2023-03-28 14:54:48.3 UTC. The measured peak count rate is 561.0 (+68.3 -74.6) counts/s above the background in the combined Veto data of all quadrants, with a total of 2819 (+428 -485) counts. The local mean background count rate was 1299.3 (+5.2 -5.5) counts/s. We measure a T90 of 12.86 (+5.41 -4.68) 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 #33533
A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), A. Melandri (INAF-OAR), T. Sbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), D.N. Burrows (PSU), J.P. Osborne (U. Leicester) and J.D. Gropp report on behalf of the Swift-XRT team:
We have analysed 9.2 ks of XRT data for GRB 230328B (Gropp et al. GCN Circ. 33527), from 94 s to 28.9 ks after the BAT trigger. The data comprise 9 s in Windowed Timing (WT) mode (taken while Swift was slewing), with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Osborne et al. (GCN Circ. 33529).
The late-time light curve (from T0+4.3 ks) can be modelled with a power-law decay with a decay index of alpha=1.06 (+/-0.07).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.89 (+/-0.08). The best-fitting absorption column is 1.37 (+0.26, -0.24) x 10^21 cm^-2, in excess of the Galactic value of 6.3 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.6 x 10^-11 (4.5 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     1.37 (+0.26, -0.24) x 10^21 cm^-2
Galactic foreground: 6.3 x 10^20 cm^-2
Excess significance: 5.1 sigma
Photon index:	     1.89 (+/-0.08)
```
If the light curve continues to decay with a power-law decay index of 1.06, the count rate at T+24 hours will be 0.052 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.9 x 10^-12 (2.3 x 10^-12) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01162001.
This circular is an official product of the Swift-XRT team.
GCN Circular #33534
T.H. Lu, S.Q. Jiang, S.Y. Fu, X. Liu (NAOC), Z.P. Zhu (NAOC, HUST), D. Xu (NAOC), X. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report:
We observed the field of GRB 230328B detected by Swift (Gropp et al., GCN 33527),using the NEXT-0.6m optical telescope located at Nanshan, Xinjiang, China. Observations started at 16:39:57 UT on 2023-03-28, i.e., 1.75 hr after the Swift/BAT trigger.
The previously reported optical afterglow (e.g., Pankov et al., GCN 33528; Belkin et al., GCN 33530) is marginally detected in our stacked image. Preliminary photometry of the afterglow has r ~ 19.1 mag, calibrated by nearby PanSTARRS stars.
GCN Circular #33535
A. Catapano (OASDG), and L. Izzo (DARK/NBI) report:
We observed the field of GRB 230328B (Gropp et al., GCN #33527) with the 0.5m telescope of the Osservatorio Astronomico S. Di Giacomo located in Agerola, Italy ( https://osservatorio.astrocampania.it/ ). We obtained two sets of 8x240s images each in the Rc and in the Ic filter under good weather conditions, with the two sets of observations separated by three hours each.
In the first dataset, we detect a faint source in the stacked Ic images at the enhanced position reported by Swift-XRT (Osborne et al., GCN #33529) and by optical telescopes (Pankov et al., GCN #33528; Belkin et al., GCN #33530, Lu et al., GCN #33534). We measure a preliminary magnitude of ~19.5 mag (AB), at exposure mid-time of MJD 60031.8 (5.1 hours after the GRB detection). We also report an upper limit of ~20.0 mag in the Rc band. In the second set of observations, the source is not detected in both filters, with upper limits of Rc > 20.2, and Ic > 19.8, respectively (MJD 60031.9, 8.1 hours after the GRB). The calibration was performed using nearby stars in the Pan-STARRS PS1 catalog, and using transformation equations to Rc and Ic magnitudes. Further analyses are ongoing.
GCN Circular #33536
A. Suresh (IITB), V. Swain (IITB), H. Kumar (IITB), P. Dorjay (IAO), V. Bhalerao (IITB), G. C. Anupama(IIA), S. Barway (IIA) report on behalf of the GIT team:
We observed GRB 230328B detected by Swift-BAT and optical afterglow discovered by Swift-UVOT (GCN 33527), with the 0.7m GROWTH-India Telescope (GIT). The observations started at 16:51:27.896 UT on 2023-03-28, 116.66 mins after the Swift-BAT trigger. We obtained multiple 300s exposures in the g', r', i', and z' filters. In stacked images for two bands, we clearly detected the afterglow at R.A.= 19h 24m 01.8s, DEC.= 80d 00' 34.5", consistent with the enhanced Swift-XRT position (GCN 33533). The photometric results follow as:
```
-------------------------------------------------------------------
 JD (mid) | T_mid-T0(hrs) | Filter| Total Exposure (s) | Magnitude (AB) |
-------------------------------------------------------------------
 2460032.22721302 | 2.539 | r'    | 1200 |20.181 +/- 0.054 |
 2460032.23485986 | 2.723 | i'    | 1200 |19.672 +/- 0.078 |
 2460032.23490645 | 2.724 | g'    | 600  |>20.089 |
 2460032.24251012 | 2.906 | z'    | 1200 |>18.503 |
-------------------------------------------------------------------
```
These magnitudes are consistent with the reported optical afterglow detections (N. Pankov et al., GCN #33528; S. Belkin et al., GCN #33530; T.H. Lu et al., GCN #33534; A. Catapano et al., GCN #33535).
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 operations of the telescope. Telescope technical details are available at https://sites.google.com/view/growthindia/.
GCN Circular #33537
C. Adami (LAM), B. Schneider (MIT), M. Birlan, T. Hromakina (Obs. de Paris), S. Basa (LAM), E. Le Floc'h, D. Turpin, D. G�tz (CEA Paris-Saclay), S. D. Vergani (GEPI, Obs. de Paris), report on behalf of a larger collaboration:
We observed the field of GRB 230328B (Gropp et al., GCN 33527; Osborne et al., GCN 33529; Dalessi et al., GCN 33531; Waratkar et al. GCN 33532) using the T120cm telescope at Observatoire de Haute-Provence (France). Six exposures were obtained in the Rc band (2x300s + 4x600s) from 28 March 2023 18:51:01 UT to 28 March 2023 20:13:46 UT (mid time ~4.5h after trigger). In the combined frame, we clearly detect the source and obtain the following magnitude:
Rc = 20.03 +/- 0.10 mag (AB)
The photometric calibration was performed using nearby stars from the PanSTARRS catalog converted in Rc and the magnitude is not corrected for Galactic extinction.
The value is consistent with early observations obtained by Pankov et al. (GCN 33528), Belkin et al. (GCN 33530) and Lu et al. (GCN 33534), and the upper limit reported by Catapano & Izzo (GCN 33535) at a similar epoch.
We acknowledge the excellent support from Observatoire de Haute Provence.
GCN Circular #33538
B. P. Gompertz (U. Birmingham), D. B. Malesani (U. Radboud and DAWN/NBI) and A. J. Levan (U. Radboud) report:
We observed GRB 230328B (Fermi GBM Team, GCN 33526; Gropp et al., GCN 33527) with the IO:O optical camera on the 2m robotic Liverpool Telescope. Observations began on March 29, 2023 at 03:20:58 UT (~12.4 hr after the Fermi and Swift triggers) and consist of a series of 15x120 s exposures in each of the SDSS r' and i' filters.
We detect the optical afterglow first reported by Swift-UVOT (Gropp et al. GCN 33527) with the following magnitudes:
```
r' = 21.16 � 0.06
i' = 20.75 � 0.07
```
Magnitudes are in the AB system, calibrated against nearby PS1 stars (Chambers et al., 2016), and are not corrected for the Galactic reddening of E(B-V) = 0.06 magnitudes along the line of sight (Schlafly & Finkbeiner 2011).

GCN Circular #33539
T. Komesh (NU), Zh. Maksut (NU), B. Grossan (UCB, NU), Zh. Abdullayev (NU), M. Krugov (FAI), report on behalf of the Energetic Cosmos Laboratory:
The Nazarbayev University Transient Telescope at Assy-Turgen Astrophysical Observatory (NUTTelA-TAO) pointed at GRB230328B on receipt of an automated GCN / BAT position alert, observing in Sloan g', r' and i' bands, with the Burst Simultaneous Three-Channel Imager (BSTI; Grossan, Kumar & Smoot 2019, JHEA, 32, 14).
We started observations at UT 2023-03-28 14:55:23, 41 s after the BAT trigger. Observations were made under clear conditions. A new and changing source consistent with the XRT position (Osborne 2023, GCN 33529) was detected. Note that these observations provide essentially full-time coverage, simultaneous in all three bands. We report the following photometric values for the OT:

tc-t0(s)  g'(mag)   exposure_time (s)                               
--------    -------    --------   
 68       17.1     54
 125     17.1     60       
 185     17.5     60       
 245     17.6     60       
 305     18.0     60       
 365     18.0     60       
 440     18.6     90       
 530     18.8     90       
 620     19.1     90       
 725     19.1     120       
 845     19.8     120       
 965     17.7     120       

 tc-t0(s)    r'(mag)    i'(mag)      exposure_time (s)
------    --------     ------          -------
45       16.5        16.1              7.5
53       16.5        15.9              7.5
60       16.4        16.0              7.5
68       16.8        16.0              7.5
75       16.4        15.9              7.5
83       16.6        16.1              7.5
90       16.5        15.9              7.5
119      16.8        16.1               15
134      16.7        16.2               15
149      16.6        16.2               15
164      17.0        16.3               15
179      16.8        16.3               15
194      17.0        16.3               15
209      16.8        16.6               15
224      17.0        16.8               15
239      17.2        16.7               15
254      17.2        16.8               15
269      17.3        16.7               15
284      17.2        16.8               15
299      17.2        16.9               15
314      17.2        17.1               15
329      17.4        17.1               15
344      17.5        16.9               15
359      17.6        17.3               15
374      17.4        16.9               15
389      17.6        17.6               15
404      17.8        17.1               15
419      17.8        16.9               15
434      17.5        17.1               15
449      17.6        17.3               15
464      17.8        17.4               15
479      17.4        17.0               15
494      18.1        17.1               15
509      17.5        17.3               15
524      17.7        17.1               15
539      18.4        17.5               15
554      17.6        17.2               15
569      17.9        17.7               15
584      18.0        17.2               15
599      17.6        17.6               15
614      17.7        17.4               15
629      17.8        17.5               15
644      17.6        17.2               15
659      17.8        17.5               15
674      17.6        17.6               15
689      18.1        17.3               15
704      18.0        17.5               15
719      17.8        17.5               15
734      17.9        17.5               15
749      18.1        17.3               15
764      18.1        17.3               15
779      18.2        17.8               15
794      18.0        17.6               15
809      18.3        17.5               15
824      18.5        17.5               15
839      18.2        17.4               15
854      18.1        17.4               15
869      18.0        18.4               15
884      17.8        17.8               15
899      18.4        17.8               15
914      18.4        17.1               15
929      17.9        18.1               15
944      17.8        17.3               15
959      18.3        18.3               15
974      18.1        17.1               15
989      18.1        17.9               15
1004     18.3        17.6               15

Uncertainties are estimated at ~ 0.1 mag for all three filters except the latest images of g’ with indications of errors ~ 0.15 mag. tc-t0 = trigger time minus image center time. Calibration was done with 3-4 bright Pan-STARRS catalog stars on our images, and no other analysis or corrections.
We caution the reader that these are preliminary results, without color or other corrections, and will likely change in small measure. Please also note that times are approximate.
----------------------------------

NU = Nazarbayev University, Nur-Sultan, Kazakhstan
UCB = University of California, Berkeley, USA
FAI = Fesenkov Astrophysical Institute, 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, Kazkhstan.

GCN Circular #33540
T.H. Lu, S.Q. Jiang, S.Y. Fu, X. Liu (NAOC), Z.P. Zhu (NAOC, HUST), D. Xu (NAOC), X. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report:
We observed the field of GRB 230328B detected by Swift (Gropp et al., GCN 33527) using the NEXT-0.6m telescope located at Nanshan, Xinjiang, China. We obtained 12x300 s frames in the Sloan r-band, starting at 14:49:11 UT on 2023-03-29 (i.e., 23.9 hr after the BAT trigger).
The optical afterglow (e.g., Pankov et al., GCN 33528; Belkin et al., GCN 33530; Lu et al., GCN 33534; Catapano et al., GCN 33535; Suresh et al., GCN 33536; Adami et al., GCN 33537; Gompertz et al., GCN 33538; Komesh et al., GCN 33539) is not detected in our stacked image. Preliminary photometric result is as follows:
```
T_mid-T0 (hr)   Filter   Upper limit(3-sigma)
    24.42             r           >21.0
```
calibrated with the nearby PanSTARRS field and not corrected for Galactic extinction.
GCN Circular #33541
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-240 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 230328B (trigger #1162001)
(Gropp, et al., GCN Circ. 33527). The BAT ground-calculated position is
RA, Dec = 291.037, 80.013 deg which is
RA(J2000) = 19h 24m 08.8s
Dec(J2000) = +80d 00' 45.3"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 46%.

The mask weighted light curve has a double peaked structure.
The light curve does not show an early afterglow as was stated in the original GCN.
T90 (15-350 keV) is 19.23 +- 3.82 sec (estimated error including systematics).

The time-averaged spectrum from T-7.38 to T+25.49 sec is best fit by a power law
with an exponential cutoff. This fit gives a photon index 1.22 +- 0.29,
and Epeak of 99.7 +- 59.7 keV (chi squared 29.53 for 56 d.o.f.). For this
model the total fluence in the 15-150 keV band is 4.3 +- 0.2 x 10^-06 erg/cm2
and the 1-sec peak flux measured from T+0.26 sec in the 15-150 keV band is
8.4 +- 0.5 ph/cm2/sec. A fit to a simple power law gives a photon index
of 1.63 +- 0.07 (chi squared 35.85 for 57 d.o.f.). 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/1162001/BA/
GCN Circular #33543
M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Kolar, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal, A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.
The long-duration GRB 230328B (Fermi/GBM detection: GCN 33526; Swift/BAT detection: GCN 33527; AstroSat/CZTI detection: GCN 33532; GECAM-B detection: trigger no. 165) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023; arXiv:2302.10048).
The detection was confirmed at the peak time 2023-03-28 14:54:49 UTC. The T90 duration measured by GRBAlpha is 8 s and the overall significance during T90 reaches 13 sigma. GRBAlpha entered the outer Van Allen radiation belt during the tail part of the burst.
The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB230328B_GCN.pdf
All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/
GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume.
GCN Circular #33544
D. Svinkin, D. Frederiks, M. Ulanov, A. Tsvetkova, A. Lysenko, A. Ridnaia, and T. Cline on behalf of the Konus-Wind team, report:
The long-duration GRB 230328B (Fermi-GBM detection: The Fermi GBM team, GCN Circ. 33526; Swift-BAT detection: Gropp et al., GCN Circ. 33527; Markwardt et al., GCN Circ. 33541; AstroSat-CZTI detection: Waratkar et al., GCN Circ. 33532; GRBAlpha detection: Dafcikova et al., GCN Circ. 33543;) triggered Konus-Wind at T0=53688.873 s UT (14:54:48.873).
The burst light curve shows a multi-peaked structure which starts at ~T0-3.3 s and has a total duration of ~12 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/GRB230328_T53688/
As observed by Konus-Wind, the burst had a fluence of 7.12(-0.51,+0.58)x10^-6 erg/cm2, and a 64-ms peak flux, measured from T0+0.430 s, of 2.87(-0.77,+0.78)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the burst (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 5 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -1.38(-0.13,+0.14) and Ep = 151(-21,+29) keV (chi2 = 73/75 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.2 (chi2 = 74/24 dof).
All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
GCN Circular #33547
Amit K. Ror, Rahul Gupta, S. B. Pandey, A. Ghosh, A. Aryan, and K. Misra (ARIES) report:
GRB 230328B was triggered by Swift-BAT at 14:54:48 UT and Fermi-GBM at 14:54:47.43 UT on 28-03-2023 (Gropp et al. 2023 GCN 33527, Dalessi et al. 2023 GCN 33531). The prompt emission was also detected by other space-based facilities like AstroSat-CZTI (Waratkar et al. 2023, GCN 33532), GRBAlpha (Dafcikova et al. 2023, GCN 33543), and Konus-Wind (Svinkin et al. 2023, GCN 33544). We searched for extended GeV emission for a temporal window of 10 ks since the GBM trigger, based on available LAT data. However, we did not find the detection of any GeV photons, and an upper limit was obtained for an energy flux < 5.2 x 10^{-10} erg/cm2/s in the energy range 100 MeV - 100 GeV with TS < 20.
We observed the field of GRB 230328B using the 3.6m Devasthal Optical Telescope located at the Devasthal observatory of the Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital, India. We have taken multiple frames with an exposure time of 300 sec each in several optical passbands. We clearly detect the optical afterglow discovered by Swift-UVOT in each individual image. The estimated preliminary magnitude is as follows:
Date Start_UT T_start-T0 (days) Filter Exp time (sec) magnitude
==============================================================
2023-03-28 21:51:54.44 ~0.29 R 300 sec 20.30 +/- 0.08
The magnitude quoted is not corrected for the galactic and host extinctions in the direction of the burst. Photometric calibration is performed using the standard stars from the USNO-B1 catalog.
The detection of the optical afterglow is consistent with the observation of Gropp et al. 2023 (GCN 33527), Pankov et al. 2023 (GCN 33528), Belkin et al. 2023 (GCN 33530), Lu et al. 2023 (GCN 33534), Catapano et al. (33535), Suresh et al. (GCN 33536), Adami et al. (GCN 33537), Gompertz et al. (GCN 33538), Komesh et al. (GCN 33539), Lu et al. 2023 (GCN 33540)
By combining our R-band magnitude with the observations of Pankov et al. 2023 (GCN 33528) and Belkin et al. 2023 (GCN 33530), we have determined the preliminary flux decay index of 0.55 +/-0.06.
This circular may be cited. The 3.6m Devasthal Optical Telescope (DOT) is a recently commissioned facility in the Northern Himalayan region of India (long: 79 41 04E, lat: 29 21 40N, alt: 2540m) owned and operated by the Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital ( https://www.aries.res.in). The authors of this GCN circular thankfully acknowledge the consistent support from the staff members to run and maintain the 3.6m DOT.
GCN Circular #33549
J. F. Agui Fernandez (IAA-CSIC), A. de Ugarte Postigo (OCA/CNRS), C. C. Thoene (ASU-CAS), M. Blazek (CAHA) , Ana Guijarro (CAHA) and S. Cikota (CAHA) report:
We observed the afterglow of GR230328B (Fermi/GBM Detection: Fermi GBM Team GCN 33526, Swift detection: Gropp et al. GCN 33527) with CAFOS mounted on the 2.2 m telescope at the Calar Alto Observatory (Almeria, Spain). The observations consisted of 5 x 360 s in Rc-band and were obtained at mean epoch of 0.4717 days after the GRB. The afterglow is clearly detected with Rc = 21.00 ± 0.06 (AB) mag measured against comparison stars from the PanSTARRS catalogue.
GCN Circular #33550
F. Kugel (KNC), D. Turpin (CEA), S. Karpov (FZU), T. Hussenot-Desenonges (IJCLab), S. Antier (OCA/Artemis), P.A. Duverne (APC, U. Paris Cit�), P. Hello (IJCLab), A. Klotz (OMP/IRAP) report on behalf of the GRANDMA/Kilonova-Catcher collaboration:
The Kilonova-Catcher telescope network responded to the alert of GRB 230328B (Swift detection: Gropp et al., GCN 33527; Fermi GBM detection: Veres et al., GCN 33526).
The KNC observations were taken by F. Kugel with an ARTEMIS CCD ATIK-460ex camera mounted in the 0.4-m f/2.8 reflector telescope in the Chante-Perdrix Observatory (France). The afterglow is detected in the 36x60s unfiltered coadded images at about 5.2 hours (midtime of the exposure) after the Swift/BAT trigger time.
Below, we report our photometric measurement in Rc magnitude.
```
-------------------------------------------------------------
T-T0 (day)  |Exposure| Filter | Mag +/- err |Mag.Lim. (AB)
-------------------------------------------------------------
0.22172 | 36 x 60s | Rc | 20.19 +/- 0.10 | 21.4 (3 sigma)
```
Our detection is consistent with the detections and limits previously reported in Pankov et al., GCN 33528.; Belkin, GCN 33530; Lu et al., GCN 33534; Catapano et al., GCN 33535; Suresh et al., GCN 33536.; Adami et al., GCN 33537; Gompertz et al., GCN 33538; Komesh et al., GCN 33539; Lu et al., GCN 33540; Ror et al., GCN 33547; Agui Fernandez et al., GCN 33549
The GRANDMA/Kilonova-Cacther images have been calibrated using field stars from the PanSTARRS-DR1 catalog using the STDpipe pipeline (Karpov 2022) and the ps1/r to Rc mag conversion from (Pancino et al. 2022).
GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS 497, 5518). Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/).
GCN Circular #33556
M. H. Siegel (PSU) and J. D. Gropp (PSU) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 230328B 114 s after the BAT trigger (Gropp et al., GCN Circ. 33527). A source consistent with the XRT position (Osborne et al. GCN Circ. 33529) is detected in the initial UVOT exposures, confirming the initial optical detections (Pankov et al., GCN Circ. 33528; Catapano & Izzo, GCN Circ. 33535; Suresh et al., GCN Circ. 33536; Adami et al., GCN Circ. 33537; Komesh et al., GCN Circ. 33539).
The preliminary UVOT position is:
```
    RA  (J2000) =  19:24:01.88 = 291.00783 (deg.)
    Dec (J2000) = +80:00:34.6  =  80.00962 (deg.)
```
with an estimated uncertainty of 0.44 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 (fc)         114          264          147         18.38 +/- 0.05
White             5537         5735          196         20.16 +/- 0.14
white            28147        28879          713         21.88 +/- 0.32
v                  655          849           39        >17.6
b                  582          774           39        >18.3
u (fc)             326          576          246         19.20 +/- 0.16
w1                 705          725           19        >18.5
w2                 805          825           19        >18.0
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.070 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #33559
N. Pankov (HSE), L. Elenin (KIAM RAS), A. Krylov (KIAM RAS), A. Pozanenko (IKI), S. Belkin (IKI) report on behalf of GRB IKI FuN:
We observed the field of GRB 230328B (Gropp et al. GCN 33527; Veres et al., GCN 33526; Dalessi et al., GCN 33531; Waratkar et al., GCN 33532; Dafcikova et al., GCN 33543; Svinkin et al. GCN 33544) with Santel-400 (0.4m) telescope of ISON-Multa observatory (Altay Republic) in Clear filter on 2023-03-28 starting on (UT) 15:16:06. We detect the optical afterglow of GRB 230328B (Gropp et al. GCN 33527; Pankov et al. GCN 33528; Belkin et al. GCN 33530; Lu et al. GCN 33534; Catapano et al. GCN 33535; Suresh et al. GCN 33536; Adami et al. GCN 33537; Gompertz et al. GCN 33538; Komesh et al. GCN 33539; Lu et al. GCN 33540; Ror et al. GCN 33547; Kugel et al. GCN 33550; Siegel et al. GCN 33556).
Preliminary photometry of the afterglow source is following
```
Date        UT start  t-T0    Exp.  Filter   OT    Err.  UL(3sigma)
                    (mid, days) (s)

2023-03-28  15:16:06 0.04603  90*60 Clear    18.9  0.1   20.0
```
The photometry is based on nearby USNO-B1.0 (R2) stars.
GCN Circular #33609
P. Minaev (IKI), A. Pozanenko (IKI) report on behalf of GRB IKI FuN:
We analyzed GRB 230328B detected by Swift (Gropp et al., GCN 33527), Fermi (Dalessi et al., GCN 33531), Astrosat (Waratkar et al., GCN 33532), GRBAlpha (Dafcikova et al., GCN 33543), Konus (Svinkin et al., GCN 33544). Using publicly available data of GBM/Fermi we estimate the duration T_90 = 25.7 +/- 0.5 s in (10 - 300) keV energy band. We also performed spectral analysis in a time interval of (-7, 30) s since GBM trigger, the best fit is obtained for CPL model with following parameters: E_p = 164 +/- 13 keV, alpha = -1.22 +/- 0.04. The fluence of F = (1.02 +/- 0.04)E-5 erg/cm**2 is obtained in 10 - 1000 keV energy band. Using T_90,i - EH diagram [1] we can classify the burst as type II (long) and find the minimal possible redshift value of z = 0.09.
The T_90,i - EH diagram for GRB 230328B can be found in http://grb.rssi.ru/GRB230328B/GRB230328B_T90i-EH.png
[1] - Minaev, Pozanenko, MNRAS, 492, 1919, 2020
GCN Circular #34141
A. Rossi, E. Maiorano, and E. Palazzi (INAF-OAS) report on behalf of the CIBO collaboration:
We observed the field of the long GRB 230328B detected by Fermi-GBM (Fermi GBM Team, GCN 33526; Dalessi et al., GCN 33531), Swift-BAT (Gropp et al., GCN 33527), AstroSat-CZTI (Waratkar et al., GCN 33532), GRBAlpha (Dafcikova et al., GCN 33543), and Konus-Wind (Svinkin et al., GCN 33544). We obtained 20 min of g'- and r'-band imaging with the LBC camera mounted on LBT (Mt Graham, AZ, USA) on 2023-06-23, ~3 months after the burst trigger. Observations were performed under mediocre weather conditions with a strong SW wind and thus an average seeing of ~2".
At the location of the optical afterglow (Pankov et al., GCN 33528; Belkin et al., GCN 33530; Lu et al., GCN 33534; Catapano et al., GCN 33535; Suresh et al., GCN 33536; Adami et al., GCN 33537; Gompertz et al., GCN 33538; Komesh et al., GCN 33539; Kumar et al., GCN 33547; Kugel et al., GCN 33550; Siegel et al., 33556; Pozanenko et al., GCN 33559), we detect a faint source which is likely the GRB host galaxy. We measure the following AB magnitudes:
```
g 24.2 +- 0.3
r 23.8 +- 0.2
```
calibrated against PanSTARRS field stars, and not corrected for the foreground Galactic extinction.
We acknowledge the excellent support from the LBTO and LBT-INAF staff, particularly D. Thompson, D. Gonzalez Huerta, F. Cusano and D. Paris, in obtaining these observations.

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Jochen Greiner, last update: 04-Jul-2023 [Disclaimer]