Gamma-ray Burst 220525A

(All information courtesy of the instrument teams.)

Previous IAU Circulars

none

Results of Observations

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 25 May 22 00:11:25 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      44
TRIGGER_NUM:     675130259
GRB_RA:           15.733d {+01h 02m 56s} (J2000),
                  16.030d {+01h 04m 07s} (current),
                  15.072d {+01h 00m 17s} (1950)
GRB_DEC:         +15.617d {+15d 37' 00"} (J2000),
                 +15.737d {+15d 44' 12"} (current),
                 +15.348d {+15d 20' 54"} (1950)
GRB_ERROR:       10.12 [deg radius, statistical plus systematic]
GRB_INTEN:       270 [cnts/sec]
DATA_SIGNIF:     12.40 [sigma]
INTEG_TIME:      1.024 [sec]
GRB_DATE:        19724 TJD;   145 DOY;   22/05/25
GRB_TIME:        654.24 SOD {00:10:54.24} UT
GRB_PHI:         337.00 [deg]
GRB_THETA:        60.00 [deg]
DATA_TIME_SCALE: 1.0240 [sec]
HARD_RATIO:      0.97
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      96%  GRB
2nd_MOST_LIKELY:   1%  Generic Transient
DETECTORS:       0,1,0, 1,0,1, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:        61.80d {+04h 07m 11s}  +20.91d {+20d 54' 27"}
SUN_DIST:         43.61 [deg]   Sun_angle= 3.1 [hr] (West of Sun)
MOON_POSTN:        2.84d {+00h 11m 22s}   -3.32d {-03d 19' 13"}
MOON_DIST:        23.10 [deg]
MOON_ILLUM:      27 [%]
GAL_COORDS:      127.00,-47.16 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       20.50,  8.23 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220525008/quicklook/glg_lc_medres34_bn220525008.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 79.28,-1.12 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(2.0<100sec) coincident with the CALET_GBM event (trignum=1337472486).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 25 May 22 00:11:33 UT
NOTICE_TYPE:     Fermi-GBM Flight Position
RECORD_NUM:      58
TRIGGER_NUM:     675130259
GRB_RA:          359.783d {+23h 59m 08s} (J2000),
                   0.070d {+00h 00m 17s} (current),
                 359.143d {+23h 56m 34s} (1950)
GRB_DEC:         +15.400d {+15d 24' 00"} (J2000),
                 +15.525d {+15d 31' 29"} (current),
                 +15.122d {+15d 07' 18"} (1950)
GRB_ERROR:       4.40 [deg radius, statistical plus systematic]
GRB_INTEN:       875 [cnts/sec]
DATA_SIGNIF:     56.50 [sigma]
INTEG_TIME:      2.048 [sec]
GRB_DATE:        19724 TJD;   145 DOY;   22/05/25
GRB_TIME:        654.24 SOD {00:10:54.24} UT
GRB_PHI:         331.00 [deg]
GRB_THETA:        45.00 [deg]
DATA_TIME_SCALE: 2.0480 [sec]
HARD_RATIO:      0.68
LOC_ALGORITHM:   3 (version number of)
MOST_LIKELY:      96%  GRB
2nd_MOST_LIKELY:   3%  Generic Transient
DETECTORS:       0,1,0, 1,0,1, 0,0,0, 0,0,0, 0,0,
SUN_POSTN:        61.80d {+04h 07m 11s}  +20.91d {+20d 54' 27"}
SUN_DIST:         58.54 [deg]   Sun_angle= 4.1 [hr] (West of Sun)
MOON_POSTN:        2.84d {+00h 11m 22s}   -3.32d {-03d 19' 11"}
MOON_DIST:        19.04 [deg]
MOON_ILLUM:      27 [%]
GAL_COORDS:      104.76,-45.62 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:        6.06, 14.19 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220525008/quicklook/glg_lc_medres34_bn220525008.gif
COMMENTS:        Fermi-GBM Flight-calculated Coordinates.  
COMMENTS:        This trigger occurred at longitude,latitude = 79.28,-1.12 [deg].  
COMMENTS:        The LC_URL file will not be created until ~15 min after the trigger.  
COMMENTS:           
COMMENTS:        NOTE: This GBM event is temporally(2.0<100sec) coincident with the CALET_GBM event (trignum=1337472486).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 25 May 22 00:11:42 UT
NOTICE_TYPE:     Fermi-GBM Ground Position
RECORD_NUM:      57
TRIGGER_NUM:     675130259
GRB_RA:           14.870d {+00h 59m 29s} (J2000),
                  15.168d {+01h 00m 40s} (current),
                  14.207d {+00h 56m 50s} (1950)
GRB_DEC:         +18.290d {+18d 17' 24"} (J2000),
                 +18.410d {+18d 24' 37"} (current),
                 +18.021d {+18d 01' 14"} (1950)
GRB_ERROR:       2.64 [deg radius, statistical only]
DATA_SIGNIF:     57.10 [sigma]
DATA_INTERVAL:   4.096 [sec]
GRB_DATE:        19724 TJD;   145 DOY;   22/05/25
GRB_TIME:        654.24 SOD {00:10:54.24} UT
GRB_PHI:         340.00 [deg]
GRB_THETA:        58.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   4173 (Gnd S/W Version number)
SUN_POSTN:        61.80d {+04h 07m 11s}  +20.91d {+20d 54' 27"}
SUN_DIST:         43.83 [deg]   Sun_angle= 3.1 [hr] (West of Sun)
MOON_POSTN:        2.84d {+00h 11m 22s}   -3.32d {-03d 19' 09"}
MOON_DIST:        24.89 [deg]
MOON_ILLUM:      27 [%]
GAL_COORDS:      125.61,-44.54 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       20.79, 11.01 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220525008/quicklook/glg_lc_medres34_bn220525008.gif
POS_MAP_URL:     http://gcn.gsfc.nasa.gov/notices_f/gbm_gnd_loc_map_675130259.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(2.0<100sec) coincident with the CALET_GBM event (trignum=1337472486).

GCN NOTICE

TITLE:           GCN/FERMI NOTICE
NOTICE_DATE:     Wed 25 May 22 00:20:20 UT
NOTICE_TYPE:     Fermi-GBM Final Position
RECORD_NUM:      0
TRIGGER_NUM:     675130259
GRB_RA:           14.870d {+00h 59m 29s} (J2000),
                  15.168d {+01h 00m 40s} (current),
                  14.207d {+00h 56m 50s} (1950)
GRB_DEC:         +18.290d {+18d 17' 24"} (J2000),
                 +18.410d {+18d 24' 37"} (current),
                 +18.021d {+18d 01' 14"} (1950)
GRB_ERROR:       1.16 [deg radius, statistical only]
GRB_DATE:        19724 TJD;   145 DOY;   22/05/25
GRB_TIME:        654.24 SOD {00:10:54.24} UT
GRB_PHI:         340.00 [deg]
GRB_THETA:        58.00 [deg]
E_RANGE:         44.032 - 279.965 [keV]
LOC_ALGORITHM:   41731 (Gnd S/W Version number)
SUN_POSTN:        61.80d {+04h 07m 13s}  +20.91d {+20d 54' 31"}
SUN_DIST:         43.84 [deg]   Sun_angle= 3.1 [hr] (West of Sun)
MOON_POSTN:        2.91d {+00h 11m 39s}   -3.28d {-03d 17' 02"}
MOON_DIST:        24.83 [deg]
MOON_ILLUM:      27 [%]
GAL_COORDS:      125.61,-44.54 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS:       20.79, 11.01 [deg] ecliptic lon,lat of the burst (or transient)
LC_URL:          http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220525008/quicklook/glg_lc_medres34_bn220525008.gif
LOC_URL:         http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220525008/quicklook/glg_locplot_all_bn220525008.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(2.0<100sec) coincident with the CALET_GBM event (trignum=1337472486).

GCN Circular #32112
The Fermi GBM team reports the detection of a likely LONG GRB
At 00:10:54 UT on 25 May 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220525A (trigger 675130259.241452 / 220525008).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 14.9, Dec = 18.3 (J2000 degrees, equivalent to J2000 00h 59m, 18d 18'), with a statistical uncertainty of 1.2 degrees.
The angle from the Fermi LAT boresight is 58.0 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220525008/quicklook/glg_skymap_all_bn220525008.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/bn220525008/quicklook/glg_healpix_all_bn220525008.fit
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220525008/quicklook/glg_lc_medres34_bn220525008.gif
GCN Circular #32113
F. Kunzweiler, B. Biltzinger, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report:
The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger 675130259 at 00:10:54 on 25 May. 2022 were automatically fitted for spectrum and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427; Berlato et al. 2019, ApJ 873, 60).
The best-fit position (1 sigma statistical errors) is:
```
RA(2000.0) = 10.61+/-1.03 deg
Decl.(2000.0) = 15.31+/-0.70 deg
```
We estimate an additional systematic error of 1 deg.
Further details are available at: https://grb.mpe.mpg.de/grb/GRB220525008/
The Healpix map can be downloaded from: https://grb.mpe.mpg.de/grb/GRB220525008/healpix
The location parameters are available as JSON at: https://grb.mpe.mpg.de/grb/GRB220525008/json
GCN Circular #32118
A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin on behalf of the HEND/Mars-Odyssey team,
D. Svinkin, D. Frederiks, A. Ridnaia, A. Lysenko, and T. Cline on behalf of the Konus-Wind team,
A. Goldstein, M. S. Briggs, and C. Wilson-Hodge on behalf of the Fermi GBM team,
and
W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr, and A.S. Gardner on on behalf of the GRS-Odyssey GRB team, report:
The long-duration GRB 220525A (Fermi GBM detection: Fermi GBM Team, GCN Circ 32112; BALROG localization: Kunzweiler et al., GCN Circ 32113) has been detected by Fermi (GBM trigger 675130259), CALET (CGBM), Konus-Wind, and Mars-Odyssey (HEND), so far, at about 654 s UT (00:10:54).
We have triangulated it to a preliminary, 3 sigma error box whose coordinates are:
```
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
    13.365 (00h 53m 28s) +16.396 (+16d 23' 46")
  Corners:
    17.561 (01h 10m 15s) +12.813 (+12d 48' 48")
     9.561 (00h 38m 15s) +18.778 (+18d 46' 42")
     9.753 (00h 39m 01s) +18.232 (+18d 13' 54")
    18.017 (01h 12m 04s) +11.551 (+11d 33' 04")
  ---------------------------------------------
```
The error box area is 4.2 sq. deg, and its maximum dimension is 10.9 deg (the minimum one is 25 arcmin). The Sun distance was 43 deg.
This box may be improved.
The IPN localization is consistent with, but reduces the area of, the Fermi GBM Final Real-time position (GCN Circ. 32112) and BALROG (GCN 32113) localizations.
A triangulation map and HEALPix FITS file are posted at http://www.ioffe.ru/LEA/GRBs/GRB220525_T00654/IPN/
The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular.
GCN Circular #32119
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-OAGH robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Mexico (OAGH National Institute for Astrophysics, Optics and Electronics) started inspect of the Fermi GRB 220525A ( Fermi GBM team, GCN 32112) errorbox 1 days 35557 sec after notice time and 1 days 35599 sec after trigger time at 2022-05-26 10:04:13 UT, with upper limit up to 17.2 mag. The observations began at zenith distance = 82 deg. The sun altitude is -24.1 deg.
The galactic latitude b = -44 deg., longitude l = 126 deg.
Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1984418
We obtain a following upper limits.
```
Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

  122089 | 2022-05-26 10:04:13 |         MASTER-OAGH | (00h 59m 08.17s , +16d 24m 55.4s) |   C |   180 | 15.5 |        
  122089 | 2022-05-26 10:04:13 |         MASTER-OAGH | (00h 59m 38.00s , +16d 01m 05.6s) |   C |   180 | 17.0 |        
  122701 | 2022-05-26 10:14:25 |         MASTER-OAGH | (00h 59m 06.62s , +16d 25m 33.8s) |   C |   180 | 16.1 |        
  122701 | 2022-05-26 10:14:25 |         MASTER-OAGH | (00h 59m 35.09s , +16d 00m 35.7s) |   C |   180 | 17.2 |        
```
Filter C is a clear (unfiltred) band.
The observation and reduction will continue. The message may be cited.
GCN Circular #32122
D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report:
The long GRB 220525A (Fermi GBM detection: Fermi GBM Team, GCN 32112; BALROG localization: Kunzweiler et al., GCN 32113; IPN triangulation: Kozyrev et al., GCN 32118) triggered Konus-Wind (KW) at T0=654.268 s UT (00:10:54.268).
The burst light curve shows a single multipeaked pulse, which starts at ~T0-3 s and has a total duration of ~12 s. The emission is seen up to ~4 MeV.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB220525_T00654/
As observed by Konus-Wind, the burst had a fluence of (1.7 ą 0.3)x10^-6 erg/cm^2 and a 64-ms peak energy flux, measured from T0 + 2.624 s, of (4.3 ą 0.7)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 15 MeV range by a Band function with the following model parameters: the low-energy photon index alpha = -0.69 (-0.22,+0.26), the high energy photon index beta = -3.0 (-7.0,+0.44), the peak energy Ep = 190 (-22,+26) keV, chi2 = 88/96 dof.
All the quoted errors are estimated at the 90% confidence level. All the presented results are preliminary.
GCN Circular #32125
Y. Kawakubo (LSU), A. Yoshida, T. Sakamoto, S. Sugita (AGU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena), and the CALET collaboration:
The long GRB 220525A (Fermi GBM Final Real-time Localization: Fermi GBM team, GCN Circ. 32112; BALROG localization: Kunzweiler et al., GCN Circ 32113; IPN triangulation: Kozyrev et al., GCN Circ 32118; Konus-Wind detection: Frederiks et al., GCN Circ 32122) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 00:10:52.713 UTC on 25 May 2022 (http://cgbm.calet.jp/cgbm_trigger/flight/1337472486/index.html). The burst signal was seen by only SGM detector.
The burst light curve shows a double-peaked structure which starts at T+1.6 sec, peaks at T+4.7 sec, and ends at T+8.7 sec. The T90 and T50 durations measured by the SGM data are 6.0 +/- 0.4 sec and 2.6 +/- 0.5 sec (40-1000 keV), respectively.
The ground processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1337472486/
The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University.
GCN Circular #32127
S. Lesage (UAH) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team:
"At 00:10:54 UT on 25 May 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220525A (trigger 675130259/220525008) which was also detected by Konus-Wind (D. Frederiks et al. 2022, GCN 32122) and CALET (Y. Kawakubo et al. 2022, GCN 32125) and localized by IPN (Kozyrev et al. 2022, GCN 32118). The Fermi GBM Final Real-time Localization (GCN 32112) is consistent with the IPN triangulation.
The angle from the Fermi LAT boresight is 58 degrees.
The GBM light curve shows a single bright emission episode with a duration (T90) of about 16.1 s (10-1000 keV). The time-averaged spectrum from T0-10 to T0+15 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.12 +/- 0.04 and the cutoff energy, parameterized as Epeak, is 176 +/- 10 keV.
The event fluence (10-1000 keV) in this time interval is (1.45 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+3.7 s in the 10-1000 keV band is 15.4 +/- 0.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog:https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html
For Fermi GBM data and info, please visit the official Fermi GBM Support Page:https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"

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Jochen Greiner, last update: 27-May-2022 [Disclaimer]