Gamma-ray Burst 220521A

(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:     Sat 21 May 22 23:20:34 UT
NOTICE_TYPE:     Swift-BAT GRB Position
TRIGGER_NUM:     1107466,   Seg_Num: 0
GRB_RA:          275.197d {+18h 20m 47s} (J2000),
                 275.461d {+18h 21m 51s} (current),
                 274.607d {+18h 18m 26s} (1950)
GRB_DEC:         +10.384d {+10d 23' 03"} (J2000),
                 +10.396d {+10d 23' 45"} (current),
                 +10.361d {+10d 21' 38"} (1950)
GRB_ERROR:       3.00 [arcmin radius, statistical only]
GRB_INTEN:       912 [cnts]    Image_Peak=101 [image_cnts]
TRIGGER_DUR:     0.256 [sec] 
TRIGGER_INDEX:   37     E_range: 25-100 keV
BKG_INTEN:       15827 [cnts]
BKG_TIME:        84010.81 SOD {23:20:10.81} UT
BKG_DUR:         8 [sec]
GRB_DATE:        19720 TJD;   141 DOY;   22/05/21
GRB_TIME:        84021.44 SOD {23:20:21.44} UT
GRB_PHI:         -78.50 [deg]
GRB_THETA:        29.50 [deg]
SOLN_STATUS:     0x20000003
RATE_SIGNIF:     21.63 [sigma]
IMAGE_SIGNIF:    9.92 [sigma]
MERIT_PARAMS:     +1  +0  +0  -2  +2  +0  +0  +0 +67  +0 
SUN_POSTN:        58.74d {+03h 54m 57s}  +20.33d {+20d 19' 55"}
SUN_DIST:        132.58 [deg]   Sun_angle= 9.6 [hr] (West of Sun)
MOON_POSTN:      324.60d {+21h 38m 23s}  -19.70d {-19d 41' 45"}
MOON_DIST:        56.97 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:       38.82, 11.47 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      276.15, 33.71 [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 = 93.59,-2.81 [deg].  
COMMENTS:           
COMMENTS:        NOTE: This BAT event is temporally(0.0<100sec) coincident with the FERMI_GBM event (trignum=674868026).

red DSS finding chart ps-file

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 21 May 22 23:20:51 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      44
TRIGGER_NUM:     674868026
GRB_RA:          269.650d {+17h 58m 36s} (J2000),
                 269.910d {+17h 59m 38s} (current),
                 269.069d {+17h 56m 16s} (1950)
GRB_DEC:         +12.000d {+12d 00' 00"} (J2000),
                 +12.000d {+11d 59' 58"} (current),
                 +12.003d {+12d 00' 11"} (1950)
GRB_ERROR:       23.82 [deg radius, statistical plus systematic]
GRB_INTEN:       249 [cnts/sec]
DATA_SIGNIF:     6.80 [sigma]
INTEG_TIME:      0.512 [sec]
GRB_DATE:        19720 TJD;   141 DOY;   22/05/21
GRB_TIME:        84021.73 SOD {23:20:21.73} UT
GRB_PHI:         134.00 [deg]
GRB_THETA:       110.00 [deg]
DATA_TIME_SCALE: 0.5120 [sec]
HARD_RATIO:      1.96
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      71%  GRB
2nd_MOST_LIKELY:  16%  SGR_1806n20
DETECTORS:       0,0,0, 0,0,0, 0,0,0, 0,1,1, 0,0,
SUN_POSTN:        58.74d {+03h 54m 58s}  +20.33d {+20d 19' 55"}
SUN_DIST:        135.44 [deg]   Sun_angle= 9.9 [hr] (West of Sun)
MOON_POSTN:      324.60d {+21h 38m 23s}  -19.70d {-19d 41' 42"}
MOON_DIST:        62.47 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:       37.92, 17.08 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      269.58, 35.44 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220521972/quicklook/glg_lc_medres34_bn220521972.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 118.03,0.00 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(0.0<100sec) coincident with the SWIFT_BAT event (trignum=1107466).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 21 May 22 23:21:09 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      57
TRIGGER_NUM:     674868026
GRB_RA:          276.320d {+18h 25m 17s} (J2000),
                 276.600d {+18h 26m 24s} (current),
                 275.694d {+18h 22m 47s} (1950)
GRB_DEC:          +2.990d {+02d 59' 24"} (J2000),
                  +3.004d {+03d 00' 14"} (current),
                  +2.961d {+02d 57' 39"} (1950)
GRB_ERROR:       12.21 [deg radius, statistical only]
DATA_SIGNIF:     8.30 [sigma]
DATA_INTERVAL:   0.512 [sec]
GRB_DATE:        19720 TJD;   141 DOY;   22/05/21
GRB_TIME:        84021.73 SOD {23:20:21.73} UT
GRB_PHI:         136.00 [deg]
GRB_THETA:        99.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4173 (Gnd S/W Version number)
SUN_POSTN:        58.74d {+03h 54m 58s}  +20.33d {+20d 19' 55"}
SUN_DIST:        136.14 [deg]   Sun_angle= 9.5 [hr] (West of Sun)
MOON_POSTN:      324.60d {+21h 38m 24s}  -19.69d {-19d 41' 38"}
MOON_DIST:        52.31 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:       32.62,  7.18 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      277.04, 26.27 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220521972/quicklook/glg_lc_medres34_bn220521972.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_674868026.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(0.0<100sec) coincident with the SWIFT_BAT event (trignum=1107466).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Sat 21 May 22 23:29:47 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     674868026
GRB_RA:          292.570d {+19h 30m 17s} (J2000),
                 292.849d {+19h 31m 24s} (current),
                 291.947d {+19h 27m 47s} (1950)
GRB_DEC:          +3.850d {+03d 51' 00"} (J2000),
                  +3.898d {+03d 53' 53"} (current),
                  +3.745d {+03d 44' 40"} (1950)
GRB_ERROR:       13.57 [deg radius, statistical only]
GRB_DATE:        19720 TJD;   141 DOY;   22/05/21
GRB_TIME:        84021.73 SOD {23:20:21.73} UT
GRB_PHI:         124.00 [deg]
GRB_THETA:        88.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:        58.75d {+03h 54m 59s}  +20.33d {+20d 19' 60"}
SUN_DIST:        121.66 [deg]   Sun_angle= 8.4 [hr] (West of Sun)
MOON_POSTN:      324.68d {+21h 38m 44s}  -19.67d {-19d 40' 02"}
MOON_DIST:        39.17 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:       40.83, -6.84 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      295.07, 25.35 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220521972/quicklook/glg_lc_medres34_bn220521972.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220521972/quicklook/glg_locplot_all_bn220521972.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 Short GRB.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(0.0<100sec) coincident with the SWIFT_BAT event (trignum=1107466).

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 21 May 22 23:22:03 UT
NOTICE_TYPE:     Swift-XRT Nack-Position
TRIGGER_NUM:     1107466,   Seg_Num: 0
POINT_RA:        275.185d {+18h 20m 44s} (J2000)
POINT_DEC:       +10.364d {+10d 21' 51"} (J2000)
IMG_START_DATE:  19720 TJD;   141 DOY;   22/05/21
IMG_START_TIME:  84117.74 SOD {23:21:57.74} UT,   96.3 [sec] since BAT Trigger Time
COUNTS:          2    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:     Sat 21 May 22 23:23:57 UT
NOTICE_TYPE:     Swift-BAT GRB Lightcurve
TRIGGER_NUM:     1107466,   Seg_Num: 0
GRB_RA:          275.197d {+18h 20m 47s} (J2000),
                 275.461d {+18h 21m 51s} (current),
                 274.607d {+18h 18m 26s} (1950)
GRB_DEC:         +10.384d {+10d 23' 03"} (J2000),
                 +10.396d {+10d 23' 45"} (current),
                 +10.361d {+10d 21' 38"} (1950)
GRB_DATE:        19720 TJD;   141 DOY;   22/05/21
GRB_TIME:        84021.44 SOD {23:20:21.44} UT
TRIGGER_INDEX:   37
GRB_PHI:         -78.50 [deg]
GRB_THETA:        29.50 [deg]
DELTA_TIME:      58.00 [sec]
TRIGGER_DUR:     0.256 [sec] 
SOLN_STATUS:     0x3
RATE_SIGNIF:     21.63 [sigma]
IMAGE_SIGNIF:    9.92 [sigma]
LC_URL:          sw01107466000msb.lc
SUN_POSTN:        58.74d {+03h 54m 58s}  +20.33d {+20d 19' 57"}
SUN_DIST:        132.58 [deg]   Sun_angle= 9.6 [hr] (West of Sun)
MOON_POSTN:      324.63d {+21h 38m 31s}  -19.69d {-19d 41' 07"}
MOON_DIST:        56.99 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:       38.82, 11.47 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:      276.15, 33.71 [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 = 93.59,-2.81 [deg].

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 21 May 22 23:24:52 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1107466,   Seg_Num: 0
POINT_RA:        275.185d {+18h 20m 44s} (J2000)
POINT_DEC:       +10.364d {+10d 21' 50"} (J2000)
POINT_ROLL:      49.393d
IMG_START_DATE:  19720 TJD;   141 DOY;   22/05/21
IMG_START_TIME:  84121.29 SOD {23:22:01.29} UT,   99.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.542
N_STARS:         190
X_OFFSET:        599 [pixels]
Y_OFFSET:        425 [pixels]
X_MAX:           1558 [pixels]
Y_MAX:           1384 [pixels]
DET_THRESH:      13
PHOTO_THRESH:    7
SL_URL:          sw01107466000msufc0099.fits
SUN_POSTN:        58.74d {+03h 54m 58s}  +20.33d {+20d 19' 57"}
SUN_DIST:        132.60 [deg]   Sun_angle= 9.6 [hr] (West of Sun)
MOON_POSTN:      324.64d {+21h 38m 33s}  -19.68d {-19d 40' 57"}
MOON_DIST:        57.00 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:       38.80, 11.47 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      276.13, 33.69 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 21 May 22 23:25:13 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1107466,   Seg_Num: 0
POINT_RA:        275.185d {+18h 20m 44s} (J2000)
POINT_DEC:       +10.364d {+10d 21' 50"} (J2000)
POINT_ROLL:      49.393d
IMG_START_DATE:  19720 TJD;   141 DOY;   22/05/21
IMG_START_TIME:  84121.29 SOD {23:22:01.29} UT,   99.8 [sec] since BAT Trigger Time
FILTER:          10, White
BKG_MEAN:        2.542
N_STARS:         190
X_OFFSET:        599 [pixels]
Y_OFFSET:        425 [pixels]
X_MAX:           1558 [pixels]
Y_MAX:           1384 [pixels]
DET_THRESH:      13
PHOTO_THRESH:    7
SL_URL:          sw01107466000msufc0099.fits
SUN_POSTN:        58.74d {+03h 54m 58s}  +20.33d {+20d 19' 57"}
SUN_DIST:        132.60 [deg]   Sun_angle= 9.6 [hr] (West of Sun)
MOON_POSTN:      324.64d {+21h 38m 34s}  -19.68d {-19d 40' 53"}
MOON_DIST:        57.00 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:       38.80, 11.47 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      276.13, 33.69 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Processed Source List.  
COMMENTS:        All 4 attachments are included.

GCN Circular #32074
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 GRB220521.97 (trigger No 1107466,18h 20m 47.28s , +10d 23m 02.4s, R=0.05) errorbox 13 sec after notice time and 33 sec after trigger time at 2022-05-21 23:20:54 UT, with upper limit up to 15.9 mag. The observations began at zenith distance = 35 deg. The sun altitude is -21.6 deg.
MASTER-Kislovodsk robotic telescope located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the Swift GRB220521.97 errorbox 16 sec after notice time and 36 sec after trigger time at 2022-05-21 23:20:57 UT, with upper limit up to 17.4 mag. The observations began at zenith distance = 33 deg. The sun altitude is -19.7 deg.
The galactic latitude b = 11 deg., longitude l = 39 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1980468
We obtain a following upper limits.
```
Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

      39 |      MASTER-Tavrida |  P\ |    10 | 15.4 |        
      41 |   MASTER-Kislovodsk |  P| |    10 | 16.4 |        
      61 |   MASTER-Kislovodsk |  P| |    50 | 17.4 |  Coadd 
      59 |   MASTER-Kislovodsk |  P| |    10 | 16.3 |        
      68 |      MASTER-Tavrida |  P\ |    10 | 15.5 |        
      77 |   MASTER-Kislovodsk |  P| |    10 | 16.2 |        
     100 |   MASTER-Kislovodsk |  P| |    20 | 17.1 |        
     103 |      MASTER-Tavrida |  P\ |    20 | 15.9 |        
     128 |   MASTER-Kislovodsk |  P| |    20 | 17.2 |        
     142 |      MASTER-Tavrida |  P\ |    20 | 15.9 |        
     161 |   MASTER-Kislovodsk |  P| |    30 | 17.2 |        
     204 |   MASTER-Kislovodsk |  P| |    40 | 17.4 |        
     257 |   MASTER-Kislovodsk |  P| |    50 | 17.2 |        
```
The observation and reduction will continue. The message may be cited.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 21 May 22 23:33:07 UT
NOTICE_TYPE:     Swift-UVOT Source List
TRIGGER_NUM:     1107466,   Seg_Num: 0
POINT_RA:        275.183d {+18h 20m 44s} (J2000)
POINT_DEC:       +10.363d {+10d 21' 47"} (J2000)
POINT_ROLL:      49.392d
IMG_START_DATE:  19720 TJD;   141 DOY;   22/05/21
IMG_START_TIME:  84333.81 SOD {23:25:33.81} UT,   312.4 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.457
N_STARS:         190
X_OFFSET:        359 [pixels]
Y_OFFSET:        185 [pixels]
X_MAX:           1798 [pixels]
Y_MAX:           1624 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw01107466000msufc0312.fits
SUN_POSTN:        58.75d {+03h 55m 00s}  +20.33d {+20d 20' 01"}
SUN_DIST:        132.61 [deg]   Sun_angle= 9.6 [hr] (West of Sun)
MOON_POSTN:      324.72d {+21h 38m 52s}  -19.66d {-19d 39' 25"}
MOON_DIST:        57.05 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:       38.80, 11.48 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      276.13, 33.69 [deg] ecliptic lon,lat of the pointing direction
COMMENTS:        SWIFT-UVOT Source List.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 21 May 22 23:33:21 UT
NOTICE_TYPE:     Swift-UVOT Processed Source List
TRIGGER_NUM:     1107466,   Seg_Num: 0
POINT_RA:        275.183d {+18h 20m 44s} (J2000)
POINT_DEC:       +10.363d {+10d 21' 47"} (J2000)
POINT_ROLL:      49.392d
IMG_START_DATE:  19720 TJD;   141 DOY;   22/05/21
IMG_START_TIME:  84333.81 SOD {23:25:33.81} UT,   312.4 [sec] since BAT Trigger Time
FILTER:          7, U
BKG_MEAN:        1.457
N_STARS:         190
X_OFFSET:        359 [pixels]
Y_OFFSET:        185 [pixels]
X_MAX:           1798 [pixels]
Y_MAX:           1624 [pixels]
DET_THRESH:      10
PHOTO_THRESH:    5
SL_URL:          sw01107466000msufc0312.fits
SUN_POSTN:        58.75d {+03h 55m 00s}  +20.33d {+20d 20' 01"}
SUN_DIST:        132.61 [deg]   Sun_angle= 9.6 [hr] (West of Sun)
MOON_POSTN:      324.72d {+21h 38m 53s}  -19.66d {-19d 39' 22"}
MOON_DIST:        57.06 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:       38.80, 11.48 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      276.13, 33.69 [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:     Sat 21 May 22 23:33:42 UT
NOTICE_TYPE:     Swift-XRT Position UPDATE
TRIGGER_NUM:     1107466,   Seg_Num: 0
GRB_RA:          275.2297d {+18h 20m 55.12s} (J2000),
                 275.4938d {+18h 21m 58.51s} (current),
                 274.6399d {+18h 18m 33.57s} (1950)
GRB_DEC:         +10.3724d {+10d 22' 20.6"} (J2000),
                 +10.3840d {+10d 23' 02.5"} (current),
                 +10.3485d {+10d 20' 54.4"} (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:  19720 TJD;   141 DOY;   22/05/21
IMG_START_TIME:  84126.00 SOD {23:22:06.00} UT,   104.6 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        58.75d {+03h 55m 00s}  +20.33d {+20d 20' 01"}
SUN_DIST:        132.57 [deg]   Sun_angle= 9.6 [hr] (West of Sun)
MOON_POSTN:      324.72d {+21h 38m 54s}  -19.66d {-19d 39' 19"}
MOON_DIST:        57.02 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:       38.83, 11.44 [deg] galactic lon,lat of the burst
ECL_COORDS:      276.19, 33.70 [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 Circular #32075
The Fermi GBM team reports the detection of a likely SHORT GRB
At 23:20:21 UT on 21 May 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220521A (trigger 674868026.727134 / 220521972).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 292.6, Dec = 3.9 (J2000 degrees, equivalent to J2000 19h 30m, 3d 53'), with a statistical uncertainty of 13.6 degrees.
The angle from the Fermi LAT boresight is 88.0 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220521972/quicklook/glg_skymap_all_bn220521972.png
The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220521972/quicklook/glg_healpix_all_bn220521972.fit
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220521972/quicklook/glg_lc_medres34_bn220521972.gif
GCN Circular #32076
S. Dichiara (PSU), J.D. Gropp (PSU), D. M. Palmer (LANL) and B. Sbarufatti (PSU) report on behalf of the Neil Gehrels Swift Observatory Team:
At 23:20:21 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 220521A (trigger=1107466). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 275.197, +10.384 which is
```
   RA(J2000) = 18h 20m 47s
   Dec(J2000) = +10d 23' 03"
```
with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a double-peaked structure with a duration of about 15 sec. The peak count rate was ~4000 counts/sec (15-350 keV), at ~0 sec after the trigger.
The XRT began observing the field at 23:21:57.7 UT, 96.3 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 275.22891, 10.37262 which is equivalent to:
```
   RA(J2000)  = 18h 20m 54.94s
   Dec(J2000) = +10d 22' 21.4"
```
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This location is 120 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at https://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 1.87 x 10^21 cm^-2 (Willingale et al. 2013).
UVOT took a finding chart exposure of 150 seconds with the White filter starting 99 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. Results from the 2.7'x2.7' sub-image are not available at this time. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.185.
Burst Advocate for this burst is S. Dichiara (simonedichiara55 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 Circular #32077
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
Using promptly downlinked XRT event data for GRB 220521A, we find an enhanced XRT position of the afterglow: RA, Dec: 275.22978, 10.37221 which is equivalent to:
```
   RA (J2000)  = 18 20 55.15
   Dec (J2000) = +10 22 19.9
```
with an uncertainty of 1.9 arcseconds (radius, 90% confidence). Analysis of the promptly available data is online at http://www.swift.ac.uk/sper/1107466.
Position enhancement is is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177).
This circular is an official product of the Swift-XRT team.

GCN NOTICE

TITLE:           GCN/SWIFT NOTICE
NOTICE_DATE:     Sat 21 May 22 23:34:18 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1107466,   Seg_Num: 0
POINT_RA:        275.183d {+18h 20m 44s} (J2000)
POINT_DEC:       +10.363d {+10d 21' 47"} (J2000)
ROLL:            49.392d
IMG_START_DATE:  19720 TJD;   141 DOY;   22/05/21
IMG_START_TIME:  84333.81 SOD {23:25:33.81} UT,   312.4 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     674868362
X_OFFSET:        918 [pixels]
Y_OFFSET:        744 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1078
Y_GRB_POS:       904
BINNING_INDEX:   1
IM_URL:          sw01107466000msuni0342.fits
SUN_POSTN:        58.75d {+03h 55m 00s}  +20.33d {+20d 20' 02"}
SUN_DIST:        132.61 [deg]   Sun_angle= 9.6 [hr] (West of Sun)
MOON_POSTN:      324.73d {+21h 38m 55s}  -19.65d {-19d 39' 12"}
MOON_DIST:        57.06 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:       38.80, 11.48 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      276.13, 33.69 [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:     Sat 21 May 22 23:26:18 UT
NOTICE_TYPE:     Swift-UVOT Image
TRIGGER_NUM:     1107466,   Seg_Num: 0
POINT_RA:        275.185d {+18h 20m 44s} (J2000)
POINT_DEC:       +10.364d {+10d 21' 50"} (J2000)
ROLL:            49.393d
IMG_START_DATE:  19720 TJD;   141 DOY;   22/05/21
IMG_START_TIME:  84121.29 SOD {23:22:01.29} UT,   99.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     674868150
X_OFFSET:        918 [pixels]
Y_OFFSET:        744 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1078
Y_GRB_POS:       904
BINNING_INDEX:   1
IM_URL:          sw01107466000msuni0129.fits
SUN_POSTN:        58.74d {+03h 54m 58s}  +20.33d {+20d 19' 58"}
SUN_DIST:        132.60 [deg]   Sun_angle= 9.6 [hr] (West of Sun)
MOON_POSTN:      324.65d {+21h 38m 36s}  -19.68d {-19d 40' 41"}
MOON_DIST:        57.01 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:       38.80, 11.47 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      276.13, 33.69 [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:     Sat 21 May 22 23:34:26 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1107466,   Seg_Num: 0
POINT_RA:        275.183d {+18h 20m 44s} (J2000)
POINT_DEC:       +10.363d {+10d 21' 47"} (J2000)
ROLL:            49.392d
IMG_START_DATE:  19720 TJD;   141 DOY;   22/05/21
IMG_START_TIME:  84333.81 SOD {23:25:33.81} UT,   312.4 [sec] since BAT Trigger Time
FILTER:          7, U
EXPOSURE_ID:     674868362
X_OFFSET:        918 [pixels]
Y_OFFSET:        744 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1078
Y_GRB_POS:       904
BINNING_INDEX:   1
IM_URL:          sw01107466000msuni0342.fits
SUN_POSTN:        58.75d {+03h 55m 00s}  +20.33d {+20d 20' 02"}
SUN_DIST:        132.61 [deg]   Sun_angle= 9.6 [hr] (West of Sun)
MOON_POSTN:      324.73d {+21h 38m 55s}  -19.65d {-19d 39' 10"}
MOON_DIST:        57.06 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:       38.80, 11.48 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      276.13, 33.69 [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:     Sat 21 May 22 23:26:28 UT
NOTICE_TYPE:     Swift-UVOT Processed Image
TRIGGER_NUM:     1107466,   Seg_Num: 0
POINT_RA:        275.185d {+18h 20m 44s} (J2000)
POINT_DEC:       +10.364d {+10d 21' 50"} (J2000)
ROLL:            49.393d
IMG_START_DATE:  19720 TJD;   141 DOY;   22/05/21
IMG_START_TIME:  84121.29 SOD {23:22:01.29} UT,   99.8 [sec] since BAT Trigger Time
FILTER:          10, White
EXPOSURE_ID:     674868150
X_OFFSET:        918 [pixels]
Y_OFFSET:        744 [pixels]
WIDTH:           160 [pixels]
HEIGHT:          160 [pixels]
X_GRB_POS:       1078
Y_GRB_POS:       904
BINNING_INDEX:   1
IM_URL:          sw01107466000msuni0129.fits
SUN_POSTN:        58.74d {+03h 54m 58s}  +20.33d {+20d 19' 58"}
SUN_DIST:        132.60 [deg]   Sun_angle= 9.6 [hr] (West of Sun)
MOON_POSTN:      324.65d {+21h 38m 37s}  -19.68d {-19d 40' 39"}
MOON_DIST:        57.01 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:       38.80, 11.47 [deg] galactic lon,lat of the pointing direction
ECL_COORDS:      276.13, 33.69 [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:     Sat 21 May 22 23:25:43 UT
NOTICE_TYPE:     Swift-XRT Position
TRIGGER_NUM:     1107466,   Seg_Num: 0
GRB_RA:          275.2287d {+18h 20m 54.88s} (J2000),
                 275.4928d {+18h 21m 58.27s} (current),
                 274.6389d {+18h 18m 33.33s} (1950)
GRB_DEC:         +10.3724d {+10d 22' 20.6"} (J2000),
                 +10.3840d {+10d 23' 02.5"} (current),
                 +10.3485d {+10d 20' 54.4"} (1950)
GRB_ERROR:       4.0 [arcsec radius, statistical plus systematic, 90% containment]
GRB_INTEN:       1.00e-10 [erg/cm2/sec]
GRB_SIGNIF:      10.00 [sigma]
IMG_START_DATE:  19720 TJD;   141 DOY;   22/05/21
IMG_START_TIME:  84126.00 SOD {23:22:06.00} UT,   104.6 [sec] since BAT Trigger Time
TAM[0-3]:        100.00 100.00 100.00 100.00
AMPLIFIER:       1
WAVEFORM:        31
SUN_POSTN:        58.74d {+03h 54m 58s}  +20.33d {+20d 19' 58"}
SUN_DIST:        132.56 [deg]   Sun_angle= 9.6 [hr] (West of Sun)
MOON_POSTN:      324.65d {+21h 38m 35s}  -19.68d {-19d 40' 48"}
MOON_DIST:        56.97 [deg]
MOON_ILLUM:      59 [%]
GAL_COORDS:       38.83, 11.44 [deg] galactic lon,lat of the burst
ECL_COORDS:      276.19, 33.70 [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 #32078
D. B. Malesani (Radboud Univ. and DAWN/NBI) and T. Pursimo (NOT) report on behalf of more people:
We observed the field of GRB 220521A (Dichiara et al., GCN 32076) with the Nordic Optical Telescope (NOT) equipped with the ALFOSC imager. In a 300-s exposure beginning on 2022 May 21.983 UT (0.248 hr after the GRB), we detect a new object consistent with the UVOT-enhanced X-ray position (Evans, GCN 32077), at J2000 coordinates:
```
RA = 18:20:55.13
Dec = +10:22:20.5
```
Calibration is against the Gaia catalog, with an expected uncertainty < 0.3".
Photometry against nearby Pan-STARRS calibrators yields r = 21.06 +- 0.03 AB. Given the consistency with the X-ray position and the lack of detection in the Pan-STARRS archival images, we conclude that this source is the optical afterglow of GRB 220521A.
GCN Circular #32079
J. P. U. Fynbo (DAWN/NBI), Z. Zhu (NAO/CAS, HUST), D. Xu (NAOC/CAS), D. B. Malesani (Radboud Univ. and DAWN/NBI), T. Pursimo (NOT), K. Matilainen (NOT), report on behalf of a larger collaboration:
Spectroscopy of the optical counterpart of GRB 220521A (Dichiara et al., GCN 32076; Malesani & Pursimo, GCN 32078) was secured using the Nordic Optical Telescope (NOT) equipped with the ALFOSC spectrograph. Grism #4 was used, covering the wavelength range 3650-9500 AA. Our first spectrum (1200 s exposure time) started on May 22.004 UT (0.76 hr after the GRB).
Preliminary analysis of the data, using archival calibration files, reveals a bright continuum in the red part, with a clear break around 8150 AA, which we interpret as due to Lyman alpha. We also identify the Lyman limit, the Lyman forest, and several metal absorption features (among which Si II 1260, O I 1302, Si II 1304, C II 1334, Si IV 1393,1402), which allow to determine z = 5.6.
The precision of the redshift can be improved after utilizing updated calibration files.
GCN Circular #32081
P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team.
Using 441 s of XRT Photon Counting mode data and 1 UVOT images for GRB 220521A, 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 = 275.22990, +10.37175 which is equivalent to:
```
RA (J2000): 18h 20m 55.18s
Dec (J2000): +10d 22' 18.3"
```
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 #32082
Goranskij V. P. (SAI, Moscow University) and Moskvitin A. S. (Special Astrophysical Observatory of RAS) report on behalf of a larger collaboration:
We observed the field of the GRB 220521A (Dichiara et al., GCN 32076; Evans, GCN 32077) with the SAO RAS 1-m telescope Zeiss-1000 + CCD-photometer. The observations started 16.6 minutes after the trigger. We obtained 200 sec. exposures in V, Rc, Ic filters.
The OT (Malesani & Pursimo, GCN 32078; Fynbo et al., GCN 32079) is clearly detected in Ic and Rc bands (with the brightness of I = 17.82 +/- 0.04; R = 20.3 +/- 0.2) and not detected in V band down to the limiting magnitude of V_lim ~ 21.4 (T_mid-T0 = 22.8 min). Preliminary photometry is based on nearby stars of PS1 catalogue, gri --> V, R, I by Lupton 2005 transformations.
GCN Circular #32085
N. P. M. Kuin (UCL-MSSL) and S. Dichiara (PSU) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 220521A 100 s after the BAT trigger (Dichiara et al., GCN Circ. 32076).No optical afterglow consistent with the XRT position (Evans et al. GCN Circ. 32081) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are:
```
Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC           100          250          147         >20.8
u_FC               312          548          232         >19.2
white              100         4178          344         >21.5
v                 4389         4589          197         >19.5
b                 3773         3973          197         >20.4
u                  312         5050          278         >19.4
w1                4798         4998          197         >20.2
m2                4593         4793          197         >19.7
w2                4184         4383          197         >19.7
```
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.185 in the direction of the burst (Schlegel et al. 1998).
GCN Circular #32086
A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), T. Sbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), D.N. Burrows (PSU) and S. Dichiara report on behalf of the Swift-XRT team:
We have analysed 8.4 ks of XRT data for GRB 220521A (Dichiara et al. GCN Circ. 32076), from 104 s to 45.1 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Evans et al. (GCN Circ. 32077).
The late-time light curve (from T0+3.8 ks) can be modelled with a power-law decay with a decay index of alpha=1.53 (+0.27, -0.23).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.90 (+0.26, -0.16). The best-fitting absorption column is 1.94 (+0.96, -0.07) x 10^21 cm^-2, consistent with the Galactic value of 1.9 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 3.7 x 10^-11 (4.8 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
```
Total column:	     1.94 (+0.96, -0.07) x 10^21 cm^-2
Galactic foreground: 1.9 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:	     1.90 (+0.26, -0.16)
```
If the light curve continues to decay with a power-law decay index of 1.53, the count rate at T+24 hours will be 1.0 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.7 x 10^-14 (4.9 x 10^-14) erg cm^-2 s^-1.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01107466.
This circular is an official product of the Swift-XRT team.
GCN Circular #32087
Alan M. Watson (UNAM), Nat Butler (ASU), William H. Lee (UNAM), Alexander Kutyrev (GSFC), Eleonora Troja (UTV), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Enrico Ramirez-Ruiz (UCSC), Jes�s Gonz�lez (UNAM), Carlos Rom�n-Z��iga (UNAM), Harvey Moseley (GSFC), Rosa L. Becerra (UNAM), Simone Dichiara (PSU), and Oc�lotl L�pez (UNAM) report:
We observed the field of GRB 220521A (Dichiara et al., GCN Circ. 32076) with the Reionization and Transients Infrared Camera (RATIR) on the 1.5m Harold Johnson Telescope at the Observatorio Astron�mico Nacional on Sierra San Pedro M�rtir from 2022/05 22.22 to 2022/05 22.47 UTC (6.04 to 12.03 hours after the BAT trigger), obtaining a total of 2.98 hours exposure in the r and i bands and 1.23 hours exposure in the Z, Y, J, and H bands.
For a source within the enhanced (Evans et al., GCN Circ. 32081) Swift-XRT error circle, in comparison with the USNO-B1 and 2MASS catalogs, we obtain the following 3-sigma upper limits:
```
  r	> 23.07
  i	> 22.77
  Z	> 21.13
  Y	> 21.87
  J	> 21.75
  H	> 21.30
```
These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB.
Our non-detection of the NOT afterglow (Malesani & Pursimo, GCN Circ. 32078) is consistent with a temporal power-law index steeper than about -0.5.
We thank the staff of the Observatorio Astron�mico Nacional in San Pedro M�rtir.
GCN Circular #32088
S. Nazarov (CrAO), A. Pozanenko (IKI), S. Belkin (IKI, HSE), N. Pankov (HSE) report on behalf of IKI GRB FuN:
We observed the GRB 220521A (Dichiara et al., GCN 32076; Fermi GBM Team, GCN 32075) with Sintesz-Newton 350mm f/5 telescope of CrAO observatory. Observation started on 2022-05-22 (UT) 01:05:40. The series consists of images with an exposure of 60 s in a Clear filter.
The optical afterglow (Malesani et al., GCN 32078; Fynbo et al., GCN 32079; Goranskij et al., GCN 32082) is not detected in the stacked image.
Preliminary photometry of the stacked images is following
```
Date       UT start   t-T0    Filter Exp.    OT    err   UL(3)
                      (mid, days)       (s)

2022-05-22 01:05:40   0.07626  Clear 9*60    n/d  n/d   18.2
```
The photometry is based on nearby USNO-B1.0 (R2) stars
```
RA DEC R2
18:21:04.76880 +10:21:04.7232 16.26
18:21:07.39800 +10:20:37.5000 16.73
```
GCN Circular #32089
S. Poolakkil (UAH) and C. Meegan (UAH) report on behalf of the Fermi GBM Team:
"At 23:20:21.73 UT on 21 May 2022, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 220521A (trigger 674868026 / 220521972) which was also detected by the Swift/BAT (Dichiara et al. 2022, GCN 32076). The Fermi GBM Final Real-time Localization (GCN 32075) is consistent with the Swift/BAT position.
The angle from the Fermi LAT boresight at the GBM trigger time is 105 degrees.
The GBM light curve consists of multiple peaks followed by some extended emission with a duration (T90) of about 14 s (50-300 keV). The time-averaged spectrum from T0-1.024 s to T0+3.072 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.51 +/- 0.23 and the cutoff energy, parameterized as Epeak, is 37 +/- 7 keV.
The event fluence (10-1000 keV) in this time interval is (6.62 +/- 0.49)E-07 erg/cm^2. The 1-sec peak photon flux measured starting from T0-0.32 s in the 10-1000 keV band is 6.3 +/- 0.4 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 #32090
A. Y. Lien (U Tampa), S. D. Barthelmy (GSFC), S. Dichiara (PSU), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), C. B. Markwardt (GSFC), 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+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 220521A (trigger #1107466) (Dichiara et al., GCN Circ. 32076). The BAT ground-calculated position is RA, Dec = 275.218, 10.372 deg which is
```
   RA(J2000)  =  18h 20m 52.3s
   Dec(J2000) = +10d 22' 20.0"
```
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 46%.
The mask-weighted light curve shows a multi-peaked structure that starts at ~T0 and ends at ~T+16 s. The two main peaks occur at ~T+0.5 s and ~T+10 s, respectively. T90 (15-350 keV) is 13.55 +- 2.69 sec (estimated error including systematics).
The time-averaged spectrum from T-0.23 to T+16.17 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.97 +- 0.18. The fluence in the 15-150 keV band is 8.1 +- 0.8 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T-0.18 sec in the 15-150 keV band is 4.7 +- 0.4 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/1107466/BA/
GCN Circular #32091
R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (College of Marin) report on behalf of a larger collaboration:
We observed GRB 220521A (Dicharia et al., GCN 32076; Fermi GBM Team, GCN 32075) with the LCO 1-m Sinistro instrument at the Teide Observatory, Tenerife site, on May 22, from 00:04 to 00:32 UT (corresponding to 0.73 to 1.20 hours from the GRB trigger time) with the Bessel R and I filters.
We performed a series of 3x300s exposures in R and I bands. We detect an optical counterpart at the NOT optical afterglow location (Malesani et al., 32078 GCN 32078) that is consistent with other optical detections (Malesani et al., GCN 32078; Fynbo et al., GCN 32079; Goranskij et al., GCN 32082). The following magnitudes are calculated using the USNO-B.1 catalog as reference:
```
R=21.57+/-0.23
I=18.61+/-0.63
```
These magnitudes are not corrected for galactic extinction.
R.S. is funded by NSF AST grant #1831682
GCN Circular #32096
M. Ferro, R. Brivio, A. Melandri, P. D'Avanzo, S. Covino, D. Fugazza, (INAF-OAB) on behalf of the REM team, report:
We observed the field of GRB 220521A (Fermi/GBM team GCN Circ. 32075; Dichiara et al., GCN Circ. 32076) with the REM 60cm robotic telescope located at the ESO premise of La Silla (Chile). The observations were carried in the g, r, i, z, J, H and K bands, starting on 2022 May 22 at 02:24:40 UT (i.e. about 3.1 hours after the burst) and lasting for about one hour.
The optical afterglow (Malesani et al., GCN Circ. 32078) is not detected. From preliminary photometry we derive the following magnitude upper limits (3sigma c.l.):
```
g > 19.5
r > 19.1
i > 18.8
z > 17.4
```
(AB; calibrated against the Pan-STARRS catalogue) at a mid time of t-t0 ~ 3.5 hours;
```
J > 16.6
H > 16.2
K > 13.5
```
(Vega; calibrated against the 2MASS catalogue) at a mid time of t-t0 ~ 3.9 hours.
GCN Circular #32097
J. Rastinejad, W. Fong (Northwestern), D. B. Malesani (Radboud Univ. and DAWN/NBI), A. Cucchiara (College of Marin/UVI), and G. Schroeder (Northwestern) report:
''We observed the location of the Fermi and Swift GRB 220521A (Fermi GBM team, GCN 32075, Dichiara et al., GCN 32076; Poolakkil & Meegan, GCN 32089, Strausbaugh et al. GCN 32091) with the Binospec imager and spectrograph mounted on the MMT 6.5-meter telescope on Mount Hopkins, Arizona. We obtain 15x100 s imaging in the z-band at a mid-time of 2022 May 23.423 (1.45 days post-burst) at an average airmass of 1.08. We detect a source at the position of the afterglow reported by Malesani & Pursimo (GCN 32078). Calibrated to PS1, we measure z = 24.04 +/- 0.16 mag (AB system and not corrected for Galactic extinction in the direction of the burst).
We thank Ryan Howie and Ben Weiner at the MMT for the rapid scheduling and execution of these observations.''
GCN Circular #32099
A. Cucchiara (College of Marin), R. Strausbaugh (U. of the Virgin Islands), J. Rastinejad, A. Nugent, W. Fong (Northwestern), D. B. Malesani (Radboud Univ. and DAWN/NBI) report on behalf of a larger collaboration:
On May 22.16 UT (T0+4.5 hr after the GRB) we observed the afterglow, of GRB 220521A (Fermi GBM team, GCN 32075; Dichiara et al., GCN 32076; Poolakkil & Meegan, GCN 32089; Strausbaugh et al., GCN 32091) with the Gemini-South telescope and the GMOS camera.
We performed a series of spectroscopic observations with the R400 grating centered at 7500 AA (2x600 s) and 8100 AA (2x600 s). Observations were obtained at an average airmass of 2.34. In our 300 s, z-band acquisition image we detected the GRB counterpart at the NOT optical afterglow location (Malesani et al., GCN 32078).
In our preliminary analysis we measured z (AB)=20.9 +/- 0.3, calibrated against 10 PS1 stars. No extinction correction has been applied.
Our visual inspection of the spectroscopic data confirms the redshift reported by Fynbo et al. (GCN 32079) as z=5.57 based on the detection of Lyman alpha, SiIV and Ni lines.
Combined with the results from MMT (Rastinejad et al., GCN 32097)we derive a decay index in z-band of alpha=1.57, consistent with the current X-ray behavior (Tohuvavohu et al., GCN 32086). Further analysis is in progress.
We thank the Gemini-S staff, particularly Javier Fuentes and Veronica Firpo, for conducting these observations.
GCN Circular #32101
S. Sato, M. Sasada, K. L. Murata, R. Hosokawa, Y. Imai, N. Ito, M. Niwano, Y. Takamatsu, M. Tateda, T. Hattori, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration:
We observed the field of GRB 220521A (The Fermi GBM team GCN Circular #32075, Dichiara et al. GCN Circular #32076, Evans et al. GCN Circular #32077, Malesani and Pursimo et al. GCN Circular #32078, Fynboet al. GCN Circular #32079, Evans et al. GCN Circular #32081, Goranskij et al. GCN Circular #32082, Kuin and Dichiara GCN Circular #32085, Tohuvavohu et al. GCN Circular #32086, Watson et al. GCN Circular #32087, Nazarov et al. GCN Circular #32088, Poolakkil and Meegan GCN Circular #32089, Lien et al. GCN Circular #32090, Strausbaugh et al. GCN Circular #32091) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope Akeno.
The observation with a series of 60 sec exposures started at 2022-05-22 11:56:05 UT (12.6 hours after the Fermi/GBM trigger). We stacked the images with good conditions. We did not detect the optical afterglow (Malesani et al. GCN Circular #32078, Goranskij et al. GCN Circular #32082, Strausbaugh et al. GCN Circular #32091, Rastinejad et al. GCN Circular #32097, Cucchiara et al. GCN Circular #32099). We obtained the 5-sigma limits of the stacked images as follows.
```
T0+[hour] | MID-UT | T-EXP[sec] | 5-sigma limits
------------------------------------------------------------------------------------------------
16.6 | 2022-05-22 15:56:34 | 6780 | g' > 19.3, Rc > 19.1, Ic > 18.6
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
```
We used PS1 catalog for flux calibration. The magnitudes are expressed in the AB system. The images were processed in real-time through the MITSuME GPU reduction pipeline (Niwano et al. 2021, PASJ, Vol.73, Issue 1, Pages 4-24; https://github.com/MNiwano/Eclaire).
GCN Circular #32103
S. Belkin (IKI, HSE), A. Pozanenko (IKI), S. Schmalz (KIAM RAS), A. Schmalz (KIAM RAS), N. Pankov (HSE), Filippo Graziani (GAUSS Srl), Riccardo Di Roberto (GAUSS Srl) report on behalf of IKI GRB FuN:
We observed the GRB 220521A (Fermi GBM Team, GCN 32075; Dichiara et al., GCN 32076; Poolakkil and Meegan, GCN 32089) with ORI-22 telescope of ISON-Castelgrande observatory. Observation started on 2022-05-21 (UT) 23:25:00, i.e. 4.65 min after GRB trigger. The series consists of 60 images with an exposure of 60 s in a Clear filter.
The optical afterglow (Malesani et al., GCN 32078; Fynbo et al., GCN 32079; Goranskij et al., GCN 32082; Strausbaugh et al., GCN 32091; Rastinejad et al., GCN 32097) is not detected in the initial part of the series and is marginally detected in the stacked image of the second part of the series.
Preliminary photometry of the stacked images is following
```
Date       UT start   t-T0    Filter Exp.    OT    err     UL(3)
                      (mid, days)       (s)

2022-05-21 23:25:00   0.012951  Clear 28*60    n/d   n/d   20.5
2022-05-21 23:57:00   0.035868  Clear 30*60    20.3  0.4   20.2
```
The photometry is based on nearby USNO-B1.0 (R2) stars
```
RA DEC R2
18:21:04.76880 +10:21:04.7232 16.26
18:21:07.39800 +10:20:37.5000 16.73
```
GCN Circular #32105
P. Minaev (IKI), A. Pozanenko (IKI), G. Mozgunov (MIPT, IKI) report on behalf of GRB IKI FuN:
We analyzed GRB 220521A till now detected by Swift and GBM/Fermi (Fermi GBM Team, GCN 32075; Dichiara et al., GCN 32076; Poolakkil and Meegan, GCN 32089) using publicly available data of GBM/Fermi and SPI-ACS/INTEGRAL. Using GBM/Fermi data we estimated the duration of T_90 = 12.0 +/- 0.5 s in 7 - 100 keV energy band and performed spectral analysis in the time interval of (-1, 12) s. The best fit is obtained for CPL model with following parameters: E_p = 62 (-15, +68) keV, alpha = -1.5 +/- 0.4. The fluence of F = (9.8 +/- 1.2)E-7 erg/cm**2 is obtained in 10 - 1000 keV energy band. The parameters are close to those reported in (Poolakkil and Meegan, GCN 32089). Using redshift of z = 5.6 (Fynbo et al., GCN 32079; Cucchiara et al., GCN 32099) we obtain E_iso = (6.2 ± 0.8)E52 erg in 1-10000 keV energy range. Using T_90,i - EH diagram [1,2] we classify the burst as type II (long burst) for any possible redshift greater than z = 0.07. T_90,i - EH diagram can be found in http://grb.rssi.ru/GRB220521A/GRB220521A_EHD.png
The burst was also detected by SPI-ACS/INTEGRAL with total statistical significance of 5.8 sigma. The angle to the SPI-ACS axis is 47 degrees. Comparing fluences of long-duration GRBs registered by both SPI-ACS and GBM/Fermi (Chelovekov et al., in preparation) we estimated the GRB 220521A fluence to be 1.1E-6 erg/cm**2 in the 10-1000 keV energy band (the 95% confidence region 3.4E-7 – 4.1E-6 erg/cm**2, incl. systematics). Light curves based on GBM/Fermi and SPI-ACS/INTEGRAL data can be found in http://grb.rssi.ru/GRB220521A/GRB220521A_light_curves.png
```
[1] - Minaev et al., MNRAS, 492, 1919, 2020
[2] - Minaev et al., Astronomy Letters, 46, 9, 573, 2020
```
GCN Circular #32107
Y.-D. Hu, E. Fernandez-Garcia, T.-R. Sun, A. J. Castro-Tirado, M.D. Caballero-Garcia, R. Sanchez-Ramirez, I. Perez-Garcia (IAA-CSIC), I. Vico, S. Cikota (CAHA), C. Perez del Pulgar, A. Castellon, M. A. Castro Tirado (Univ. de Malaga), R. Fernandez-Munoz (IHSM/UMA-CSIC) and M. Jelinek (ASU-CAS), on behalf of a larger collaboration, report:
Following the detection of GRB 220521A by Fermi (GBM team GCNC 32075) and Swift (Dichiara et al. GCNC 32076), the 0.6m BOOTES-2/TELMA robotic telescope in Algarrobo Costa (Malaga, Spain) automatically respond to this event and pointed to the Swift/XRT position (Evans et al. GCNC 32077) on May 21, 23:20:56 UT (35 s post trigger). Due to the cloudy weather, only useful frames were obtained starting at 23:39:23 UT (i.e. ~19 min after trigger). The afterglow detected by both XRT and NOT is not detected in our co-added image (60 x 23 s, clear filter), down to 18.4 mag.
Later on, we also triggered the 2.2m CAHA telescope (+ CAFOS) at the Calar Alto Observatory (Almeria, Spain). Images (Sloan i-band) were gathered since May. 23 01:36 UT (i.e. 1.1 day post trigger). On the co-added image (14 x 180 s), the afterglow is not detected down to i = 24.1 mag.
Those non-detections are consistent with the previous reports from NOT (Malesani et al. GCNC 32078, Fynbo et al. GCNC 32079), SAO (Goranskij et al. GCNC 32082), RATIR (Watson et al. GCNC 32087), Sintesz-Newton (Nazarov et al. GCNC 32088), LCO (Strausbaugh et al. GCNC 32091), REM (Ferro et al. GCNC 32096), MMT (Rastinejad et al. GCNC 32097), Gemini (Cucchiara et al. GCNC 32099), MITSuME (Sato et al. GCNC 32101) and ISON-Castelgrande (Belkin et al. GCNC 32103).
We thank the staff at IHSM/UMA-CSIC La Mayora and CAHA for their excellent support.
GCN Circular #32110
T. Laskar (University of Bath), S. Bhandari (ASTRON/JIVE), K. D. Alexander (Northwestern), R. Margutti (Berkeley), E. Berger (Harvard), W. Fong (Northwestern), R. Chornock (Berkeley), C. G. Mundell (University of Bath), and P. Schady (University of Bath) report on behalf of a larger collaboration:
"We observed GRB 220521A (Dichiara et al., GCN 32076) with the Atacama Large Millimeter/Submillimeter Array (ALMA) at 97.5 GHz beginning on 2022 May 23 05:30 UT (1.26 days after the burst).
Preliminary analysis reveals a millimeter source with flux density of ~ 0.3 mJy at position:
```
RA (J2000) = 18:20:55.12 (+/- 0.03")
Dec (J2000) = 10:22:20.52 (+/- 0.03")
```
consistent with the X-ray position (Evans et al., GCN 32077) and optical position (Malesani et al., GCN 32078).
We thank the JAO staff, AoD, P2G, and the entire ALMA team for their help with these observations."
GCN Circular #32111
T. Laskar (University of Bath), S. Bhandari (ASTRON/JIVE), K. D. Alexander (Northwestern), E. Berger (Harvard), R. Chornock (UC Berkeley), D. Coppejans (Northwestern), M. Drout (U. Toronto), H. van Eerten (University of Bath), W. Fong (Northwestern), C. Guidorzi (U. Ferrara), R. Margutti (UC Berkeley), C. G. Mundell (University of Bath), P. Schady (University of Bath), and G. Schroeder (Northwestern) report:
"We observed GRB 220521A (Dichiara et al., GCN 32076) with the Australia Telescope Compact Array (ATCA) at 39 GHz beginning on 2022 May 24 14:44 UT. We detect a radio counterpart at a position consistent with the X-ray position (Evans et al., GCN 32077), optical position (Malesani et al., GCN 32078), and mm-band position (Laskar et al., GCN 32110) with a preliminary flux density of ~ 0.2 mJy at a mid-time of 2.4 days after the burst.
We thank the CSIRO staff for approving and scheduling these observations.
The Australia Telescope Compact Array is part of the Australia Telescope National Facility which is funded by the Australian Government for operation as a National Facility managed by CSIRO. We acknowledge the Gomeroi people as the traditional owners of the Observatory site."

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Jochen Greiner, last update: 24-May-2022 [Disclaimer]