).
The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.
GCN Circular #32132
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the Fermi/LAT GRB 220527A.
Automated analysis of the XRT data will be presented online at
https://www.swift.ac.uk/ToO_GRBs/00021503
Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the Fermi/LAT event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a
GCN Circular after manual consideration.
Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).
This circular is an official product of the Swift-XRT team.
GCN Circular #32133
J. Mangan (UCD), R. Dunwoody (UCD), and C.Meegan (UAH)
report on behalf of the Fermi GBM Team:
At 09:17:15.73 UT on 27 May 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220527A (trigger 675335840 / 220527387),
which was also detected by the Fermi LAT (Bissaldi et al. 2022, GCN 32131)
and AGILE (Ursi et al 2022, GCN 32129). The Fermi GBM Final Real-time
Localization
(GCN 32130) is consistent with the Fermi LAT position.
The angle from the Fermi LAT boresight at the GBM trigger time is 49
degrees.
The GBM light curve consists of a double peak emission
with a duration (T90) of about 10.5 s (50-300 keV).
The time-averaged spectrum from T0-0.13 s to T0+21.38 s is best fit by
a Band function with Epeak = 151.6 +/- 2.7 keV,
alpha = -0.75 +/- 0.02, and beta = -2.55 +/- 0.05.
The event fluence (10-1000 keV) in this time interval is
(5.69 +/- 0.04)E-5 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+7.4 s in the 10-1000 keV band
is 92.6 +/- 0.7 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 NOTICE
TITLE: GCN/SWIFT NOTICE
NOTICE_DATE: Fri 27 May 22 22:39:09 UT
NOTICE_TYPE: Swift-UVOT Processed Image
TRIGGER_NUM: 1108208, Seg_Num: 0
POINT_RA: 244.994d {+16h 19m 58s} (J2000)
POINT_DEC: -15.695d {-15d 41' 43"} (J2000)
ROLL: 1.982d
IMG_START_DATE: 19726 TJD; 147 DOY; 22/05/27
IMG_START_TIME: 81190.78 SOD {22:33:10.78} UT, 512.9 [sec] since BAT Trigger Time
FILTER: 10, White
EXPOSURE_ID: 675383620
X_OFFSET: 1067 [pixels]
Y_OFFSET: 584 [pixels]
WIDTH: 160 [pixels]
HEIGHT: 160 [pixels]
X_GRB_POS: 1227
Y_GRB_POS: 744
BINNING_INDEX: 1
IM_URL: sw01108208000msuni0542.fits
SUN_POSTN: 64.77d {+04h 19m 05s} +21.41d {+21d 24' 42"}
SUN_DIST: 174.31 [deg] Sun_angle= 12.0 [hr] (West of Sun)
MOON_POSTN: 36.26d {+02h 25m 02s} +13.05d {+13d 02' 50"}
MOON_DIST: 151.75 [deg]
MOON_ILLUM: 6 [%]
GAL_COORDS: 359.06, 23.74 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 245.86, 5.67 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: SWIFT-UVOT Processed Image.
COMMENTS: The GRB Position came from the XRT Position Command.
COMMENTS: The image has 2x2 binning (compression).
COMMENTS: All 4 attachments are included.
GCN Circular #32135
B. Sbarufatti (PSU), A.P. Beardmore (U. Leicester), J.P. Osborne (U.
Leicester), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), E.
Ambrosi (INAF-IASFPA) , D.N. Burrows (PSU), J. D. Gropp (PSU) and P.A.
Evans (U. Leicester) report on behalf of the Swift-XRT team:
Swift-XRT has performed follow-up observations of the
Fermi/LAT-detected burst GRB 220527A (Bissaldi et al. GCN Circ. 32131),
collecting 1.7 ks of Photon Counting (PC) mode data between T0+30.1 ks
and T0+31.9 ks.
Two uncatalogued X-ray sources are detected, of which one ("Source 2")
is above the RASS 3-sigma upper limit at this position, and is
therefore likely the GRB afterglow. Using 1733 s of PC mode data and 1
UVOT image, we find an enhanced XRT position (using the XRT-UVOT
alignment and matching UVOT field sources to the USNO-B1 catalogue):
RA, Dec = 323.52805, -14.97183 which is equivalent to:
RA (J2000): 21h 34m 06.73s
Dec(J2000): 14d 58' 18.6"
with an uncertainty of 2.6 arcsec (radius, 90% confidence). This
position is 4.9 arcmin from the Fermi/LAT position. The light curve is
consistent with a constant source of mean count rate 3.9e-01 ct/sec. A
power-law fit gives an index of 0.6 (+2.5, -1.1).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.83 (+0.21, -0.20). The
best-fitting absorption column is 9.8 (+6.1, -3.5) x 10^20 cm^-2,
consistent with the Galactic value of 6.2 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 (4.2 x
10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 9.8 (+6.1, -3.5) x 10^20 cm^-2
Galactic foreground: 6.2 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index: 1.83 (+0.21, -0.20)
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00021503.
The results of the full analysis of the XRT observations are available
at https://www.swift.ac.uk/ToO_GRBs/00021503.
This circular is an official product of the Swift-XRT team.
GCN Circular #32136
The Swift/UVOT began observations of the Fermi/LAT localization (GCN
32131) of GRB 220527A , collecting 1.7 ks of u band data between
T0+30.1 ks
and T0+31.9 ks after the Fermi GBM detection (32133).
A source consistent with the XRT afterglow position (GCN 32135) is
detected in the UVOT observation.
The preliminary UVOT position is:
RA,Dec (J2000): 323.52803, -14.97169
with an estimated u band magnitude of 17.8 +/- 0.07 in the UVOT
photometric system.
GCN Circular #32137
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-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) was pointed to the LAT GRB220527.39 (trigger No 675335840,21h 34m 16.80s , -14d 54m 00.0s, R=0.08) errorbox 27168 sec after notice time and 47094 sec after trigger time at 2022-05-27 22:22:10 UT, with upper limit up to 17.4 mag. The observations began at zenith distance = 76 deg. The sun altitude is -78.9 deg.
The galactic latitude b = -43 deg., longitude l = 38 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=1987766
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
47185 | 2022-05-27 22:22:10 | MASTER-SAAO | (21h 33m 06.91s , -15d 07m 06.2s) | C | 180 | 17.4 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular #32138
Y. Imai, S. Sato, R. Hosokawa, K. L. Murata, M. Sasada, M. Niwano, N.
Ito, 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 220527A (A. Ursi et al. GCN Circular
#32129, The Fermi GBM team et al. GCN Circular #32130, Bissaldi et
al. GCN Circular #32131, Evans et al. GCN Circular #32132, Mangan et
al. GCN Circular #32133, Sbarufatti et al. GCN Circular #32135,
Tohuvavohu et al. GCN Circular #32136,) 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
2022-05-27 16:05:50 UT (6.8 hours after the AGILE detection). We
stacked the images with good conditions. Here we report magnitudes by
the forced-photometry at the Swift/XRT position (Sbarufatti et al. GCN
Circular #32135).
T0+[hour] |MID-UT | T-EXP[sec] | magnitudes of forced-photometry
------------------------------------------------------------------------------------------------
7.5 | 2022-05-27 16:46:53| 3780 | g'=18.9 +/- 0.2, Rc=18.5 +/- 0.1,
Ic=18.3 +/- 0.1
8.7 | 2022-05-27 17:58:38| 3420 | g'=18.9 +/- 0.2, Rc=18.6 +/- 0.1,
Ic=18.7 +/- 0.2
------------------------------------------------------------------------------------------------
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 #32139
K. Yamaoka (Nagoya U), A. Yoshida, T. Sakamoto, S. Sugita (AGU),
Y. Kawakubo (LSU), 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 bright long GRB 220527A (AGILE detection: Ursi et al., GCN Circ. 32129;
Fermi GBM Final Real-time Localization: Fermi GBM team, GCN Circ. 32130;
Fermi-LAT detection: Bissaldi et al., GCN Circ. 32131) triggered the CALET
Gamma-ray Burst Monitor (CGBM) at 09:17:14.518 UTC on 27 May 2022
(http://cgbm.calet.jp/cgbm_trigger/flight/1337678064/index.html).
The burst signal was seen by all CGBM detectors.
The burst light curve shows a multi-peaked structure which starts
at T+0.5 sec, peaks at T+9.1 sec, and ends at T+21.9 sec.
The T90 and T50 durations measured by the SGM data are 10.2 +/- 1.0 sec
and 3.9 +/- 0.1 sec (40-1000 keV), respectively.
The ground processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1337678064/
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at the Waseda University.
GCN Circular #32140
R. Gopalakrishnan (IUCAA), V. Prasad (IUCAA), G. Waratkar (IITB), A.
Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka
University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report
on behalf of the AstroSat CZTI collaboration:
Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al.,
2021, JApA, 42, 73) showed detection of a long GRB 220527A which was
also reported by AGILE (Ursi et al. GCN 32129), Fermi-GBM (GCN 32130),
Fermi-LAT (Bissaldi et al., GCN 32131), Swift-XRT (Sbarufatti et al.,
GCN 32135), Swift-UVOT (Tohuvavohu et al., GCN 32136) and CALET (Yamaoka
et al., GCN 32139).
The source was clearly detected in the 20-200 keV energy range. The
light curve showed multiple peaks of emission with the strongest peak at
2022-05-27 09:17:23.55 UTC. The measured peak count rate associated with
the burst is 1879 (+251, -171) counts/s above the background in the
combined data of four quadrants, with a total of 5318 (+224, -235)
counts. The local mean background count rate was 496 (+4, -5) counts/s.
Using cumulative rates, we measure a T90 of 7 (+1, -1) s.
It was also clearly detected in the CsI anticoincidence (Veto) detector
in the 100-500 keV energy range. The light curve showed multiple peaks
of emission with the strongest peak at 2022-05-27 09:17:19.39 UTC. The
measured peak count rate is 1880 (+96, -93) counts/s above the
background in the combined Veto data of four quadrants, with a total of
11483 (+534, -559) counts. The local mean background count rate was 1644
(+6, -6) counts/s. We measure a T90 of 14 (+3, -2) s from the cumulative
Veto light curve.
CZTI GRB detections are reported regularly on the payload site at
http://astrosat.iucaa.in/czti/?q=grb [1]. 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.
Links:
------
[1] http://astrosat.iucaa.in/czti/?q=grb
GCN Circular #32141
D. Xu (NAOC), Z.P. Zhu (NAOC, HUST), L. Izzo (DARK/NBI), S.Y. Fu, X. Liu
(NAOC), M. Aron (NOT), report on behalf of a larger collaboration:
We observed the field of GRB 220527A detected by AGILE (Ursi et al., GCN
32129), Fermi (Fermi GBM team, GCN 32130; Bissaldi et al., GCN 32131),
CALET (Yamaoka et la., GCN 32139), and AstroSat (Gopalakrishnan et al.,
GCN 32140), using the 2.56-m Nordic Optical Telescope (NOT) equipped
with the ALFSOC camera. We carried out 3x120 s Sloan r-band photometry
starting at 03:55:22 UT on 2022-05-28, i.e., 18.6 hr since the Fermi/GBM
trigger, followed by 2x1800 s spectroscopy covering wavelength of ~ 3600
- 9000 AA.
The previously reported optical afterglow (Tohuvavohu et al., GCN 32136;
Imai et al., GCN 32138) is clearly detected in each single r-band image,
and has decayed to r = 19.55 +/- 0.02 mag, calibrated with the
PAN-STARRS field.
A blue continuum is throughout the spectrum, superimposed with a few
relatively prominent absorption features, among which we identify as Ni
II, Fe II, Mn II, Mg II, all at a common redshift of z =0.857, using old
calibrations. A weak emission feature might also be detected,
interpreted as due to [O II] at the same redshift. We thus conclude
z=0.857 is the redshift of the burst.
GCN Circular #32143
S. de Wet (UCT), P.J. Groot (Radboud/UCT/SAAO) and P.M. Vreeswijk (Radboud)
report on behalf of the MeerLICHT consortium:
Following the detection of GRB 220527A by AGILE (Ursi et al., GCN 32129),
Fermi/GBM (Fermi GBM Team, GCN 32130) and Fermi/LAT (Bissaldi et al., GCN
32131), the 0.6m wide-field MeerLICHT telescope, located at Sutherland,
South Africa, obtained 2x600 s exposures in the q-band and a single 300 s
exposure in each of the g and r bands covering the entire Fermi/LAT error
region beginning 17.68 hours after the GRB trigger.
We detect the previously reported afterglow to GRB 220527A (Sbarufatti et
al., GCN 32135; Tohuvavohu, GCN 32136; Imai et al., GCN 32138; Xu et al.,
GCN 32141) at the UVOT position with AB magnitudes:
g = 19.72 +/- 0.04
r = 19.55 +/- 0.06
q = 19.57 +/- 0.02
MeerLICHT is built and run by a consortium consisting of Radboud
University, University of Cape Town, the South African Astronomical
Observatory, the University of Oxford, the University of Manchester and the
University of Amsterdam.
GCN Circular #32144
A. Saccardi (GEPI, Observatoire de Paris), L. Izzo (DARK/NBI), and D. Xu (NAOC)
report on behalf of the Stargate collaboration:
We observed the afterglow counterpart of GRB 220527A detected by Swift-XRT (B. Sbarufatti et al. GCN Circ. 32135) during the follow-up observations of the Fermi/LAT-detected burst GRB 220527A (E. Bissaldi et al. GCN Circ. 32131) using the ESO VLT UT3 (Melipal) equipped with the X-shooter spectrograph.
A spectrum was acquired covering the wavelength range 3000-21000 AA, and consisting of 4 exposures of 600 s each. The observation started at 06:19:10 UT on 2022-05-28 (0.88 days after the GRB detection by Fermi/GBM).
From the detection of several absorption lines, which we identified as due to Al III, Ni II, Fe II, Mn II, Mg II, Mg I, and Ca II we infer a redshift z=0.857, which is in agreement with the redshift reported by the NOT (D. Xu et al. GCN Circ. 32141). We note also the presence of a possible intervening absorber, through the identification of Mg II, at z=0.455 which coincides with the photometric redshift of a nearby source visible in the Pan-STARRS archival images.
We acknowledge excellent support from the ESO observing staff in Paranal, in particular Rob van Holstein (ESO fellow) and Felipe Gaete (Telescope operator).
GCN Circular #32145
P. D'Avanzo, D. Fugazza, A. Melandri, S. Covino (INAF-OAB) on behalf of the REM team, report:
We observed the field of GRB 220527A (Ursi et al., GCN Circ. 32129; Fermi GBM Team, GCN Circ. 32130; Bissaldi et al., GCN Circ. 32131) 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 and K bands, starting on 2022 May 28 at 07:27:54 UT (i.e. about 22.2 hours after the burst).
From preliminary photometry we derive the following magnitudes and upper limits (3sigma c.l.) for the optical afterglow (Tohuvavohu et al., GCN Circ. 32136; Imai et al., GCN Circ. 32138; Xu et al., GCN 32141; de Wet et al., GCN Circ. 32143):
g = 20.4 +/- 0.3 (*)
r = 19.4 +/- 0.2
i = 19.4 +/- 0.2
z > 18.4
(* marginal detection; AB calibrated against the Pan-STARRS catalogue)
J > 17.7
K > 14.9
(Vega; calibrated against the 2MASS catalogue)
at a mid time of t-t0 ~ 22.4 hours.
GCN Circular #32146
Tianrui Sun (Purple Mountain Observatory), Lei Hu, Maokai Hu, Xuefeng Wu, Lei Liu, Kelai Meng, Xiaoyan Li (Nanjing Institute of Astronomical Observation Technology),
Zhengyang Li, Xiangyan Yuan, Lifan Wang (TAMU), Xiaofeng Wang (Tsinghua University), report on behalf the AST3 Team:
Following the detection of GRB 220527A detected by AGILE (Ursi et al., GCN
32129), Fermi (Fermi GBM team, GCN 32130; Bissaldi et al., GCN 32131), CALET (Yamaoka et la., GCN 32139), and AstroSat (Gopalakrishnan et al.,
GCN 32140), we use Antarctic Survey Telescope 3-3 at Yaoan Astronomy Observation (China, Yunnan) to follow up for the afterglow (Sbarufatti et
al., GCN 32135; Tohuvavohu, GCN 32136; Imai et al., GCN 32138; Xu et al.,
GCN 32141; Simon et al. 32143; D'Avanzo et al., 32145).
We observed the target position with 14 x 60s exposure in g-band starting from 27 May 2022, UTC 21:11:36.003,
about 11.9 hours after the burst.
The magnitude detection at the Swift UVOT position (GCN 32136) on the combined images for the GRB afterglow :
g=19.3 +/- 0.06
We used the PS1 catalogue as the magnitude reference for calibration.
GCN Circular #32152
A. Lysenko, D. Frederiks, A. Ridnaia, D. Svinkin, A. Tsvetkova, M. Ulanov,
and T. Cline on behalf of the Konus-Wind team, report:
The long-duration GRB 220527A
(AGILE detection: Ursi et al., GCN Circ. 32129;
Fermi-LAT detection: Bissaldi et al., GCN Circ. 32131;
Fermi-GBM detection: The Fermi GBM team, GCN Circ. 32130;
Mangan et al., GCN Circ. 32133;
CALET detection: Yamaoka et al., GCN Circ. 32139;
AstroSat CZTI detection: Gopalakrishnan et al., GCN Circ. 32140)
triggered Konus-Wind at T0=33441.517 s UT (09:17:21.517).
The burst light curve shows a multipeaked structure
which starts at ~T0-4.1 s and has a total duration of ~21.3 s.
The emission is seen up to ~16 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB220527_T33441/
As observed by Konus-Wind, the burst
had a fluence of 5.98(-0.31,+0.32)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+5.152s,
of 1.73(-0.21,+0.22)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the burst
(measured from T0 to T0+13.568 s)
is best fit in the 20 keV - 16 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.80(-0.12,+0.13),
the high energy photon index beta = -2.55(-0.13,+0.10),
the peak energy Ep = 154(-10,+10) keV
(chi2 = 115/98 dof).
The spectrum near the maximum count rate
(measured from T0+3.584 to T0+5.376 s)
is best fit in the 20 keV - 16 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.49(-0.18,+0.21),
the high energy photon index beta = -3.24(-0.53,+0.31),
the peak energy Ep = 146(-9,+9) keV
(chi2 = 72/64 dof).
For both spectra, we note a prominent count excess over the model
at energies above ~5 MeV. The excess can be modeled by
an additional power-law component with a photon index of <~2.
Assuming the redshift z=0.857 (Xu et al., GCN Circ. 32141)
and a standard cosmology model with H_0 = 67.7 km/s/Mpc,
Omega_M = 0.310, and Omega_Lambda = 0.689 (Planck Collab 2018, Paper VI),
we estimate the following rest-frame parameters:
the isotropic energy release E_iso is 1.22(-0.06,+0.07)x10^53 erg,
the peak luminosity L_iso is 6.53(-0.81,+0.84)x10^52 erg/s,
and the rest-frame peak energy of the time-integrated spectrum,
Ep,i,z is 286(-18,+19) keV
With the obtained estimates, GRB 220527A lies inside 68% prediction bands
for both 'Amati' and 'Yonetoku' relations for the sample of >300 long KW
GRBs
with known redshifts (Tsvetkova et al., 2017; Tsvetkova et al., 2021),
see http://www.ioffe.ru/LEA/GRBs/GRB220527_T33441/GRB220527A_rest_frame.pdf
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
GCN Circular #32158
WeiKang Zheng, Thomas G. Brink and Alexei V. Filippenko (UC Berkeley)
report on behalf of the KAIT GRB team:
We observed the field of GRB 220527A (AGILE detection: Ursi et al., GCN
32129; Fermi detection: Fermi GBM team, GCN 32130, Bissaldi et al., GCN
32131, Mangan et al., 32133; CALET detection: Yamaoka et al., GCN 32139;
AstroSat detection: Gopalakrishnan et al., GCN 32140; Konus-Wind detection:
Lysenko et al. GCN 32152)
with the 3m Shane telescope (located at Lick Observatory) on May 28
and 30 UT. Observations were performed in unfiltered images with the
Kast Dual Spectrograph simultaneously in both blue and red side with
the d57 dichroic. We detected the optical afterglow (Tohuvavohu et al.,
GCN 32136; Imai et al., GCN 32138; Xu et al., GCN 32141; de Wet et al.,
GCN 32143; D'Avanzo et al., GCN 32145; Sun et al., GCN 32146)
in our coadd images. We calibrated our blue side images to g band and
red side images to I band from the Pan-STARRS1 catalog. We measure its
brightness to be the following:
1.09d g = 20.3 +/- 0.2
1.09d I = 19.4 +/- 0.2
3.08d I = 21.2 +/- 0.3
GCN Circular #32159
M. Niwano, S. Sato, M. Tateda, N. Higuchi, T. Hattori, R. Hosokawa, K.
L. Murata, M. Sasada, N. Ito, Y. Takamatsu, Y. Imai, Y. Yatsu, and N.
Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration:
We observed the field of GRB 220527A (A. Ursi et al. GCN Circular
#32129, The Fermi GBM team GCN Circular #32130, E. Bissaldi et al. GCN
Circular #32131, P. A. Evans et al. GCN Circular #32132, J. Mangan et
al. GCN Circular #32133, B. Sbarufatti et al. GCN Circular #32135,
Tohuvavohu et al. GCN Circular #32136, Y. Imai et al. GCN Circular
#32138, K. Yamaoka et al. GCN Circular #32139, R. Gopalakrishnan et al.
GCN Circular #32140, D. Xu et al. GCN Circular #32141, S. de Wet et al.
GCN Circular #32143, P. D'Avanzo et al. GCN Circular #32145, T. Sun et
al. GCN Circular #32146, A. Lysenko et al. GCN Circular #32152, W. Zheng
et al. GCN Circular #32158) 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 2022-05-28
16:06:39 UT (1.3 days after the AGILE detection). We stacked the images
with good conditions. The point source was presumably detected at the
Swift/XRT position (Sbarufatti et al. GCN Circular #32135) with S/N~3
only in the Rc-band image. Here we report the Rc-band magnitude by the
forced-photometry at the position and 5-sigma limits.
T0+[days] | MID-UT | T-EXP[sec] | magnitudes of forced-photometry | 5-sigma limits
------------------------------------------------------------------------------------------------
1.3 | 2022-05-28 17:39:36 | 4980 | Rc=20.5+/-0.3 | g'<18.6, Rc<19.3, Ic<18.5
------------------------------------------------------------------------------------------------
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 #32169
R. Ruffini, Y. Aimuratov, L. Becerra, C.L. Bianco, Y.-C. Chen, C.
Cherubini, S. Eslamzadeh, S. Filippi, M. Karlica, L. Li, G.J. Mathews, R.
Moradi, M. Muccino, G.B. Pisani, F. Rastegarnia, J.A. Rueda, N. Sahakyan,
Y. Wang, S.-S. Xue, on behalf of the ICRA, ICRANet-INAF team, report:
GRB 220527A is observed by AGILE (Ursi et al. 2022, GCN 32129), Fermi (GCN
32130, Bissaldi et al. 2022, GCN 32131, Mangan et al. 2022, GCN 32133),
Swift (B. Sbarufatti et al. 2022 GCN 32135, A. Tohuvavohu. 2022, GCN
32136), CALET (Yamaoka et al. 2022, GCN 32139), AstroSat (Gopalakrishnan et
al. 2022, GCN 32140), and Konus-Wind (Lysenko et al. 2022, GCN 32152).
With the redshift z = 0.857 of GRB 220527A (D. Xu et al. 2022, GCN 32141),
the isotropic energy of this GRB in 10 keV - 10 MeV, and 20 keV - 16 MeV
ranges are E_iso=(2.60 +\- 0.14)x10^{53} erg, and
E_iso=1.22(-0.06,+0.07)x10^{53} erg, respectively (A. Lysenko et al. 2022,
GCN 32152).
The ultra-relativistic prompt emission phase of this GRB, originating from
the over-criticl electric field around the black hole (Moradi et al 2021,
Phys. Rev. D 104, 063043) extends from rest-frame time of 3.7s to 5.4s. The
UPE phase is best fitted by a cutoff power-law plus blackbody spectrum
(CPL+BB) with best fit parameters of: alpha = -0.57, Ep = 109.5 keV, beta =
-2.36, kT = 47.8 keV.
In addition to the above observations, the following observation of the GeV
emission (E. Bissaldi et al. 2022, GCN 32131), originated from the newborn
black hole (R. Ruffini et al. 2019 ApJ 886 82) and the afterglow emission
(B. Sbarufatti et al. 2022 GCN 32135, A. Tohuvavohu. 2022, GCN 32136)
originated from the newborn neutron star (J.A. Rueda et al. 2020 ApJ 893
148), confirm this GRB is a BDHN I.
Following Ruffini et al. 2021 (MNRAS, 504, 5301,doi:10.1093/mnras/stab724),
we predict the emergence of an optical supernova peak to be detected at
(25.1+/-3.5) days after the trigger (June 21th 2022, uncertainty from June
18th 2022 to June 24th 2022), with the bolometric optical luminosity of
L_SN,b=(9.0+/-2.7)x10^{42} erg/s.
Follow-up optical observations for the SN peak are encouraged.
Previous IAU Circulars 
