GRB 220623A
GCN Circular 32243
Subject
GRB 220623A: Swift detection of a burst
Date
2022-06-23T07:20:12Z (3 years ago)
From
Kim Page at U.of Leicester <kimlpage1978@gmail.com>
B. Sbarufatti (PSU), K. L. Page (U Leicester),
T. M. Parsotan (GSFC/UMBC/CRESSTII), M. H. Siegel (PSU) and
A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift
Observatory Team:
At 07:04:14 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 220623A (trigger=1111672). Swift did not slew immediately
to the burst.
The BAT on-board calculated location is
RA, Dec 145.462, +75.828 which is
RA(J2000) = 09h 41m 51s
Dec(J2000) = +75d 49' 42"
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 25 sec. One peak occurred before
the trigger and another occurred at the trigger time. The peak count
rate was ~9000 counts/sec (15-350 keV), at ~0 sec after the trigger.
Due to an observing constraint, Swift will not slew until T0+61.4
minutes. There will be no XRT or UVOT data until this time.
Burst Advocate for this burst is B. Sbarufatti (bxs60 AT psu.edu).
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)
GCN Circular 32244
Subject
GRB 220623A: Swift-XRT observations
Date
2022-06-23T08:35:46Z (3 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
J.A. Kennea (PSU), G. Cusumano (INAF-IASF PA), M. Perri (SSDC &
INAF-OAR), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester) and
D.N. Burrows (PSU) report on behalf of the Swift-XRT team:
The XRT began observing the field of GRB 220623A at 08:11:23.5 UT,
4029.1 seconds after the BAT trigger. Using promptly downlinked data we
find an uncatalogued X-ray source located at RA, Dec 145.39717,
75.82155 which is equivalent to:
RA(J2000) = 09h 41m 35.32s
Dec(J2000) = +75d 49' 17.6"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 61 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at https://www.swift.ac.uk/sper.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (2.49 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 3.4
(+2.74/-2.39) x 10^21 cm^-2 (90% confidence).
GCN Circular 32245
Subject
GRB 220623A: iTelescope optical upper limit
Date
2022-06-23T10:17:01Z (3 years ago)
From
Filipp Dmitrievich Romanov at Amateur astronomer <filipp.romanov.27.04.1997@gmail.com>
I observed the field of GRB 220623A (Sbarufatti et al., GCN Circ.
32243) remotely using telescope T24 (0.61-m f/6.5 reflector + CCD) of
iTelescope.Net in Sierra Remote Observatory (Auberry, California, USA)
on 2022-06-23. Three images (exposures 300 seconds, BINx1) were
obtained with Ic filter with mid time 09:26:42 UTC (8548 seconds after
the trigger). I did not detect any optical afterglow in the BAT and
the XRT (Kennea et al., GCN Circ. 32244) positions. The magnitude
limit is about 18 mag, compared to the magnitudes of nearby stars from
the USNO-B1.0 Catalog (Monet et al., 2003).
F. D. Romanov.
GCN Circular 32246
Subject
GRB 220623A: AstroSat CZTI detection
Date
2022-06-23T11:15:23Z (3 years ago)
From
Gaurav Waratkar at IIT,Bombay <gauravwaratkar@iitb.ac.in>
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 the detection of a long GRB 220623A which was
also detected by Swift-BAT (Sbarufatti et al., GCN 32243), Swift-XRT
(Kennea et al., GCN 32244) and INTEGRAL SPI-ACS (TrigNum: 9966).
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
2022-06-23 07:04:14.500 UTC. The measured peak count rate associated
with the burst is 127 (+38, -17) counts/s above the background in the
combined data of three (out of four) quadrants, with a total of 738
(+204, -207) counts. The local mean background count rate was 360 (+2,
-2) counts/s. Using cumulative rates, we measure a T90 of 9 (+9, -2) 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 2022-06-23 07:04:13.771 UTC. The
measured peak count rate is 570 (+74, -60) counts/s above the background
in the combined Veto data of all quadrants, with a total of 2919 (+440,
-459) counts. The local mean background count rate was 1502 (+5, -5)
counts/s. We measure a T90 of 8 (+4, -1) 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. 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.
GCN Circular 32247
Subject
GRB 220623A: AGILE detection
Date
2022-06-23T11:41:48Z (3 years ago)
From
Alessandro Ursi at INAF/IAPS <alessandro.ursi@gmail.com>
A. Ursi (INAF/IAPS), F. Lucarelli, C. Pittori, F. Verrecchia (SSDC, and
INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A. Argan, M.
Cardillo, C. Casentini, Y. Evangelista, L. Foffano, E. Menegoni, G. Piano
(INAF/IAPS), A. Bulgarelli, A. Di Piano, V. Fioretti, N. Parmiggiani
(INAF/OAS-Bologna), M. Romani (INAF/OA-Brera), M. Marisaldi
(INAF/OAS-Bologna, and Bergen University), M. Pilia, A. Trois
(INAF/OA-Cagliari), I. Donnarumma (ASI), A. Giuliani (INAF/IASF-Mi), F.
Longo (Univ. Trieste and INFN Trieste), and P. Tempesta (TeleSpazio),
report on behalf of the AGILE Team:
The AGILE satellite detected the GRB 220623A at T0 = 2022-06-23 07:04:14 s
(UTC), reported by Swift BAT (GCN #32243), Swift XRT (GCN #32244), and
AstroSat CZTI (GCN #32246). The burst is clearly visible in the AGILE
scientific ratemeters of the SuperAGILE (SA; 20-60 keV), MiniCALorimeter
(MCAL; 0.4-100 MeV), and AntiCoincidence (AC; 50-200 keV) detectors. The
event lasted about 25 s and it released a total number of 1950 counts in
the SA detector (above a background rate of 85 Hz), 29800 counts in the
MCAL detector (above a background rate of 1050 Hz), and 72370 counts in the
AC detector (above a background rate of 2770 Hz). The AGILE ratemeters
light curves can be found at
http://www.agilescienceapp.it/notices/GRB220623A_AGILE_RM.png .
The event also triggered a partial high time resolution MCAL data
acquisition, from T1 = 2022-06-23 07:04:09.65 s (UTC) to T2 = 2022-06-23
07:04:16.15 s (UTC), and released 4200 counts in the detector, above a
background rate of 530 Hz. The MCAL light curve can be found at
http://www.agilescienceapp.it/notices/GRB220623A_078852_583052654.000000.png
. At the T0, the event was 35 deg off-axis.
Additional analysis of AGILE data is in progress. Automatic MCAL GRB alert
Notices can be found at: https://gcn.gsfc.nasa.gov/agile_mcal.html.
GCN Circular 32248
Subject
GRB 220623A: Enhanced Swift-XRT position
Date
2022-06-23T15:39:19Z (3 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1568 s of XRT Photon Counting mode data and 5 UVOT
images for GRB 220623A, 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 = 145.39376, +75.82100 which is equivalent
to:
RA (J2000): 09h 41m 34.50s
Dec (J2000): +75d 49' 15.6"
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 32251
Subject
GRB 220623A: BOOTES-5/JGT optical afterglow detection
Date
2022-06-23T17:57:34Z (3 years ago)
From
Youdong HU at IAA-CSIC <huyoudong072@hotmail.com>
Y.-D. Hu, E. Fernandez-Garcia, I. Perez-Garcia, A. J. Castro-Tirado, M.D. Caballero-Garcia, R. Sanchez-Ramirez (IAA-CSIC), D. Hiriart and W. H. Lee (UNAM), C. J. Perez del Pulgar and I. Carrasco (UMA), I. H. Park (SKKU) on behalf of a larger collaboration, report:
Following the detection of GRB 220623A by both Swift (Sbarufatti et al. GCNC 32243), AstroSat (Gopalakrishnan et al. GCNC 32246) and AGILE (Ursi et al. GCNC 32247), the 60cm BOOTES-5/JGT robotic telescope at Observatorio Astronomico Nacional in San Pedro Martir (Mexico) automatically responded to the burst on June 23 at 07:05:03 UT (i.e. ~ 47 s after trigger). In the first 1 s exposure image, an optical afterglow is detected at the enhanced Swift-XRT position (Beardmore et al. GCNC 32248) with a preliminary magnitude of 17.1 +- 0.2 mag (clear filter). Further observations are ongoing and encouraged.
We thank the staff at San Pedro Martir Observatory for their excellent support.
GCN Circular 32252
Subject
GRB 220623A: Swift/UVOT Upper Limits
Date
2022-06-23T18:32:09Z (3 years ago)
From
Alexander Belles at PSU/Swift <aub1461@psu.edu>
A. Belles (PSU) and B. Sbarufatti (PSU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 220623A
4034 s after the BAT trigger (Sbarufatti et al., GCN Circ. 32243).
No optical afterglow consistent with the XRT position
(Kennea et al. GCN Circ. 32244)
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 4034 4184 147 >19.9
white 4034 5415 344 >20.1
v 4190 9642 326 >18.9
b 5010 5210 197 >19.4
u 4805 5005 197 >19.0
w1 4600 4800 197 >19.3
m2 4395 4595 197 >19.9
w2 5421 5621 197 >19.6
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.036 in the direction of the burst
(Schlegel et al. 1998).
GCN Circular 32253
Subject
GRB 220623A: NOT optical observations
Date
2022-06-23T23:43:30Z (3 years ago)
From
Daniele B Malesani at Radboud U <d.malesani@astro.ru.nl>
D. B. Malesani (Radboud Univ. and DAWN/NBI), L. Izzo (DARK/NBI), J. S.
Thomsen (NOT), R. Clavero (IAC) report on behalf of a larger collaboration:
We observed the field of GRB 220623A (Sbarufatti et al., GCN 32243)
using the Nordic Optical Telescope (NOT) equipped with the ALFOSC
imager. Two sets of observations were acquired in the r and z filters,
with mid times 2022 Jun 23.890 and 23.903 UT (14.3 and 14.6 hr after the
trigger, respectively). The exposure times were 3x300 and 5x200 s in r
and z, respectively.
No source is detected in our images within or close to the GRB XRT
position (Evans et al., GCN 32248), down to the following 3-sigma limits:
r > 23.4 (AB);
z > 22.5 (AB).
Flux calibration was carried out against nearby stars from the
Pan-STARRS catalog.
GCN Circular 32254
Subject
GRB 220623A: Swift-XRT refined Analysis
Date
2022-06-24T01:14:07Z (3 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
V. D'Elia (SSDC & INAF-OAR), A. D'Ai (INAF-IASFPA), D.N. Burrows (PSU),
J. D. Gropp (PSU), P.A. Evans (U. Leicester), J.P. Osborne (U.
Leicester), K.L. Page (U. Leicester), A. Melandri (INAF-OAB) and B.
Sbarufatti report on behalf of the Swift-XRT team:
We have analysed 7.4 ks of XRT data for GRB 220623A (Sbarufatti et al.
GCN Circ. 32243), from 4.0 ks to 57.1 ks after the BAT trigger. The
data are entirely in Photon Counting (PC) mode. The enhanced XRT
position for this burst was given by Beardmore et al. (GCN Circ.
32248).
The light curve can be modelled with a power-law decay with a decay
index of alpha=1.85 (+0.14, -0.13).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.92 (+0.19, -0.18). The
best-fitting absorption column is 2.0 (+0.7, -0.6) x 10^21 cm^-2, in
excess of the Galactic value of 2.5 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 3.7 x 10^-11 (4.8 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 2.0 (+0.7, -0.6) x 10^21 cm^-2
Galactic foreground: 2.5 x 10^20 cm^-2
Excess significance: 4.7 sigma
Photon index: 1.92 (+0.19, -0.18)
If the light curve continues to decay with a power-law decay index of
1.85, the count rate at T+24 hours will be 1.9 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 7.0 x
10^-14 (9.3 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/01111672.
This circular is an official product of the Swift-XRT team.
GCN Circular 32255
Subject
GRB 220623A: AbAO optical upper limit
Date
2022-06-24T01:50:04Z (3 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
N. Pankov (IKI), A. Pozanenko (IKI), R. Ya. Inasaridze (AbAO), S.
Belkin (IKI), V. R. Ayvazian (AbAO), D. Datashvili (AbAO), G. V.
Kapanadze (AbAO) report on behalf of GRB IKI FuN
We observed the field of GRB 220623A detected by Swift (Sbarufatti et
al., GCN 32243; Kennea et al., GCN 32244), AstroSat (Gopalakrishnan et
al., GCN 32246) and AGILE (Ursi et al., GCN 32247) with AS-32 telescope
of Abastumani Observatory (AbAO). We do not detect any optical sources
within enhanced XRT position (Beardmore et al., GCN 32248). In
particular we do not detect the source reported by Y.-D. Hu et al. (GCN
32251). Preliminary upper limit of a stacked image is following:
Date, UT start, t-T0, Exp., Filter, OT, Err, UL(3 sigma)
(mid, days)
2022-06-23 17:53:02 0.47313 65*60 R n/d n/d 21.5
The photometry is based on nearby USNO-B1.0 stars, R2 magnitude
USNO-B1.0_id R2
1658-0059467 15.40
1658-0059509 15.39
GCN Circular 32258
Subject
Konus-Wind detection of GRB 220623A
Date
2022-06-24T12:32:17Z (3 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
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 220623A (Swift detection: Sbarufatti et al., GCN Circ. 32243;
AstroSat-CZTI detection: Gopalakrishnan et al., GCN Circ 32246;
AGILE detection: Ursi et al., GCN Circ 32247)
triggered Konus-Wind (KW) at T0=25447.564 s UT (07:04:07.564).
The burst light curve shows a bright, double-peaked structure
which starts at ~T0-0.2 s and has a total duration of ~15 s.
A weaker emission in visible in the KW lc until ~T0+50 s.
The emission at the bright phase of the event is seen up to ~2.5 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB220623_T25447/
As observed by Konus-Wind, the burst had
a fluence of (2.5 �� 0.3)x10^-5 erg/cm^2 and
a 64-ms peak energy flux, measured from T0 + 0.064 s,
of (8.8 �� 0.8)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum (measured from T0 to T0+49.408 s)
is best fit in the 20 keV - 15 MeV range
by a power law with exponential cutoff (CPL) model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -1.13(-0.11,+0.12) and Ep = 869(-224,+363) keV (chi2 = 93/98 dof).
Fitting this spectrum by a Band function yields the same values of alpha and Ep,
and an upper limit on the high energy photon index beta of -2.6 (chi2 = 93/97 dof).
The spectrum near the peak count rate (measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 15 MeV range by a CPL function
with alpha = -0.82(-0.09,+0.10) and Ep = 910(-136,+177) keV (chi2 = 86/98 dof).
Fitting this spectrum by a Band function yields the same values of alpha and Ep,
and an upper limit on the high energy photon index beta of -2.9 (chi2 = 86/97 dof).
All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary.
GCN Circular 32264
Subject
GRB 220623A: Swift-BAT refined analysis
Date
2022-06-24T18:49:10Z (3 years ago)
From
Tyler Parsotan at UMBC/GSFC/CRESST II <parsotat@umbc.edu>
���
T. Parsotan (GSFC/UMBC), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), (i.e. the Swift-BAT team):
Using the data set from T-240 to T+842 sec from the recent telemetry downlink, we report further analysis of BAT GRB 220623A (trigger #1111672) (Sbarufatti, et al., GCN Circ. 32243). The BAT ground-calculated position is
RA, Dec = 145.459, 75.823 deg which is
RA(J2000) = 09h 41m 50.1s
Dec(J2000) = +75d 49' 22.9"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 94%.
The BAT light curve showed a triple-peaked structure. One possible precursor peak occurred prior to the trigger, another occurred at the trigger time, and the final occurred 10 s post trigger. At ~40 s there may be broad emission as well. T90 (15-350 keV) is 57.11 +- 8.53 sec (estimated error including systematics).
The time-averaged spectrum from -3.84 to 73.652 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.33 +- 0.07. The fluence in the 15-150 keV band is 3.5 +- 0.1 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T-0.15 sec in the 15-150 keV band is 4.5 +- 0.2 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/1111672/BA/
GCN Circular 32271
Subject
GRB 220623A: T193-OHP optical upper limit
Date
2022-06-26T16:43:42Z (3 years ago)
From
Benjamin Schneider at CEA <benjamin.schneider@cea.fr>
B. Schneider, D. Turpin, E. Le Floc���h (CEA), C. Adami,
S. Basa (LAM), S. Vergani, J. Palmerio (GEPI)
report on behalf of a larger collaboration:
We observed the field of GRB 220623A (Sbarufatti et al. GCN 32243;
Gopalakrishnan et al. GCN 32246; Ursi et al. GCN 32247) using
the T193cm telescope at Observatoire de Haute-Provence (France)
equipped with the MISTRAL spectro-imager. Six exposures
(1x300s + 5x600s) were obtained in the i band using the red MISTRAL
set-up from 2022 23 Jun 21:32:10 UT to 2022 23 Jun 23:05:49 UT
(mid time ~15.2h after trigger). Data reduction is still preliminary.
In the combined frame, we do not detect any source within the 2.2 arsec
error circle of the enhanced XRT position (Evans et al. GCN 32248;
Beardmore et al. GCN 32248) down to the following 3-sigma limit:
i > 21.5 mag (AB)
The photometric calibration was performed using nearby stars
from the PanSTARRS catalog.
We acknowledge the support from Observatoire de Haute-Provence,
in particular Jean-Pierre Troncin and Jerome Schmidt.
GCN Circular 32273
Subject
GRB 220623A: GIT optical upper limits.
Date
2022-06-27T08:51:40Z (3 years ago)
From
Harsh Kumar at Indian Inst of Tech,Bombay <harshkosli13@gmail.com>
V. Swain (IITB), H. Kumar (IITB), K. Angail (IAO), V. Bhalerao (IITB), G.
C. Anupama (IIA), S. Barway (IIA) report on behalf of the GIT team:
We observed GRB 220623A detected by Swift (Sbarufatti et al., GCN 32243;
Kennea et al., GCN 32244), AstroSat (Gopalakrishnan et al., GCN 32246) and
AGILE (Ursi et al., GCN 32247), with the 0.7m GROWTH-India Telescope (GIT).
The observations started at 15:05:15 UT on 2022-06-23, 8.02 hours after the
Swift trigger. We obtained multiple 300-sec exposures in the g', r' and i'
filters. We did not detect any new source in our stacked images within the 2.1
arcsec radius circle around R.A.= 09h 41m 34.50s, Dec.= +75d 49' 15.6��� (Phil
Evans et al. GCN #32248). The obtained upper limits follow as:
-----------------------------------------------------------------------
JD(mid) | T_mid-T0(hrs) | Exposure(sec) | Filter | Lim_mag(5-sigma) |
-----------------------------------------------------------------------
2459754.132298985 | 8.10 | 3 x 300 (stacked) | r' | > 21.10 |
2459754.141603815 | 8.32 | 2 x 300 (stacked) | g' | > 21.01 |
2459754.149142145 | 8.50 | 2 x 300 (stacked) | i' | > 20.23 |
-----------------------------------------------------------------------
These upper limits are consistent with Benjamin et al.(GCN #32271), Alexei
et al.(GCN #32255), Daniele et al.(GCN #32253), Alexander et al.(GCN
#32252), Filipp et al.(GCN #32245). The magnitudes are calibrated against
PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Galactic
extinction.
The GROWTH India Telescope (GIT) is a 70-cm telescope with a 0.7-degree
field of view, set up by the Indian Institute of Astrophysics (IIA) and the
Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and
IUSSTF. It is located at the Indian Astronomical Observatory (Hanle),
operated by IIA. We acknowledge funding by the IITB alumni batch of 1994,
which partially supports operations of the telescope. Telescope technical
details are available at https://sites.google.com/view/growthindia/.
GCN Circular 34139
Subject
Konus-Wind detection of GRB 220623A
Date
2023-07-03T19:54:02Z (2 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia,
Y. Temiraev, A. Tsvetkova, M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:
The long-duration GRB 220623A
(MAXI-GSC detection: Hagiwara et al., GCN 34068)
was detected by Konus-Wind (KW) in the waiting mode.
A Bayesian block analysis of the KW waiting mode data
in the 20-1500 keV band reveals a multi-peaked structure
which starts at ~T0 and ends at ~T0+580 s,
where T0 = T0(MAXI) = 07:23:37 UT.
The KW light curve of this burst is available at
http://www.ioffe.ru/LEA/GRBs/GRB230623A/
Modelling a time-integrated spectrum of the burst
by a power law (PL) model dN/dE ~ E^alpha
yields alpha = -2.18(-0.04,+0.05).
The spectrum near the peak count rate,
measured from T0+43.303 s to T0+75.687 s,
can be described by a power law with exponential cutoff (CPL) model
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -1.58(-0.13, +0.15) and Ep = 243(-57,+141) keV.
The total burst fluence is 5.77(-0.34,+0.52)x10^-5 erg/cm^2,
and the 2.944 s peak energy flux is 6.08(-0.97,+1.40)x10^-7 erg/cm^2.
(both in the 20 keV - 10 MeV energy range).
All the quoted errors are estimated at the 68% confidence level.
All the presented results are preliminary.