GRB 221017A
GCN Circular 32872
Subject
Konus-Wind detection of GRB 221017A
Date
2022-10-28T12:04:43Z (3 years ago)
From
Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>
A.Ridnaia, D. Frederiks, A.Lysenko, D. Svinkin,
A. Tsvetkova, M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:
The long-duration GRB 221017A
(MAXI/GSC detection: Nawa et al., GCN 32777;
IPN triangulation: Kozyrev et al., GCN 32787;
CALET/CGBM detection: Cherry et al., GCN 32813)
triggered Konus-Wind at T0=19789.594 s UT (05:29:49.594).
The burst light curve shows a multipeaked structure
which starts at ~T0-19.1 s and has a total duration of ~332 s.
The emission is seen up to ~6 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB221017_T19789/
As observed by Konus-Wind, the burst
had a fluence of 3.90(-0.32,+0.32)x10^-4 erg/cm2,
and a 64-ms peak flux, measured from T0+175.872 s,
of 9.62(-1.55,+1.56)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the burst
(measured from T0 to T0+312.320 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.99(-0.06,+0.07),
the high energy photon index beta = -2.75(-0.46,+0.23),
the peak energy Ep = 237(-15,+16) keV
(chi2 = 119/98 dof).
The spectrum near the maximum count rate
(measured from T0+151.552 to T0+182.016 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.92(-0.04,+0.04),
the high energy photon index beta = -2.98(-0.35,+0.22),
the peak energy Ep = 288(-13,+13) keV
(chi2 = 137/98 dof).
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
GCN Circular 32813
Subject
GRB 221017A: CALET Gamma-Ray Burst Monitor detection
Date
2022-10-21T15:48:27Z (3 years ago)
From
Yuta Kawakubo at Louisiana State U./CALET <kawakubo1@lsu.edu>
M. L. Cherry (LSU), A. Yoshida, T. Sakamoto, S. Sugita (AGU),
Y. Kawakubo (LSU), 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),
S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena),
and the CALET collaboration:
The long GRB 221017A (MAXI/GSC detection: Nawa et al., GCN Circ. 32777;
IPN triangulation: Kozyrev et al., GCN Circ 32787) was detected in the
ground analysis of the CALET Gamma-ray Burst Monitor (CGBM) data around
05:29:49 UTC on October 17, 2022 (referenced to GCN Circ 32787).
The burst signal was seen by all CGBM detectors.
The burst light curve shows a multi-peaked structure that starts
at T-20.5 sec, peaks at T+176.6 sec and ends at T+670.4 sec.
The T90 and T50 durations measured by the SGM data are 191.9 +/- 44.4 sec
and 52.7 +/- 0.5 sec (40-1000 keV), respectively.
The ground-processed light curve is available at
http://cgbm.calet.jp/cgbm_trigger/ground/1350019714/
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.
GCN Circular 32807
Subject
GRB 221017A: Swift-XRT observations
Date
2022-10-20T14:42:17Z (3 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
J.P. Osborne (U. Leicester), M.G. Bernardini (INAF-OAB), E. Ambrosi
(INAF-IASFPA) , M. Capalbi (INAF-IASFPA), J. D. Gropp (PSU), S.
Dichiara (PSU), J.A. Kennea (PSU), K.L. Page (U. Leicester) and P.A.
Evans (U. Leicester) report on behalf of the Swift-XRT team:
Swift-XRT has performed follow-up observations of the MAXI-detected
burst GRB 221017A (Nawa et al. GCN Circ. 32777), collecting 1.9 ks of
Photon Counting (PC) mode data between T0+196.7 ks and T0+225.8 ks.
Two uncatalogued sources are detected:
- Source 1
RA (J2000.0): 116.8816 = 07:47:31.58
Dec (J2000.0): 39.3449 = +39:20:41.5
Error: 10.7" (radius, 90% confidence)
Avg. XRT count-rate: 5.4(+2.6,-2.0)x10^(-3) cts/s
- Source 2
RA (J2000.0): 116.9220 = 07:47:41.27
Dec (J2000.0): 39.2614 = +39:15:41.2
Error: 10.0" (radius, 90% confidence)
Avg. XRT count-rate: 3.3(+2.1,-1.5)x10^(-3) cts/s
Both sources lie inside the overlap of the MAXI localization error box
(Nawa et al. GCN Circ. 32777) and the IPN triangulation region (Kozyrev
et al. GCN Circ. 32787).
The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at
https://www.swift.ac.uk/ToO_GRBs/00021529.
This circular is an official product of the Swift-XRT team.
GCN Circular 32790
Subject
GRB 221017A: Swift ToO observations
Date
2022-10-18T13:50:15Z (3 years ago)
From
Phil Evans at U of Leicester <pae9@leicester.ac.uk>
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the MAXI GRB 221017A.
Automated analysis of the XRT data will be presented online at
https://www.swift.ac.uk/ToO_GRBs/00021529
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 MAXI 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 32787
Subject
IPN triangulation of GRB 221017A (long)
Date
2022-10-17T20:49:59Z (3 years ago)
From
Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>
A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin
on behalf of the HEND/Mars-Odyssey team,
A. Ridnaia, D. Frederiks, D. Svinkin, A. Lysenko,
and T. Cline on behalf of the Konus-Wind team,
E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB 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 221017A
(MAXI/GSC detection: Nawa et al., GCN 32777)
has been detected by MAXI (GSC), INTEGRAL (SPI-ACS), Konus-Wind,
and Mars-Odyssey (HEND), so far, at about 19789 s UT (05:29:49).
We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
---------------------------------------------
RA(2000), deg Dec(2000), deg
---------------------------------------------
Center:
116.901 (07h 47m 36s) +39.742 (+39d 44' 32")
Corners:
116.215 (07h 44m 52s) +41.438 (+41d 26' 15")
117.708 (07h 50m 50s) +38.402 (+38d 24' 08")
117.493 (07h 49m 58s) +37.908 (+37d 54' 28")
116.024 (07h 44m 06s) +40.992 (+40d 59' 30")
---------------------------------------------
The error box area is 1.01 sq. deg, and its maximum
dimension is 3.7 deg (the minimum one is 19 arcmin).
The Sun distance was 91 deg.
This box may be improved.
The IPN localization is consistent with, but reduces the area of, the
MAXI/GSC localization (GCN 32777).
A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB221017_T19789/IPN
The Konus-Wind time history and spectrum will be given
in a forthcoming GCN Circular.
GCN Circular 32777
Subject
GRB 221017A: MAXI/GSC detection
Date
2022-10-17T07:16:28Z (3 years ago)
From
Motoko Serino at Aoyama Gakuin U. <serino@phys.aoyama.ac.jp>
S. Nawa(Chuo U.), M. Serino(AGU), H. Negoro, M. Nakajima, K. Kobayashi, M. Tanaka, Y. Soejima (Nihon U.),
T. Mihara, T. Kawamuro, S. Yamada, T. Tamagawa, M. Matsuoka (RIKEN),
T. Sakamoto, S. Sugita, H. Hiramatsu, A. Yoshida (AGU),
Y. Tsuboi, W. Iwakiri, J. Kohara, S. Urabe, N. Nemoto (Chuo U.),
M. Shidatsu, M. Iwasaki (Ehime U.),
N. Kawai, M. Niwano, R. Hosokawa, Y. Imai, N. Ito, Y. Takamatsu (Tokyo Tech),
S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, T. Kurihara (JAXA),
Y. Ueda, S. Ogawa, K. Setoguchi, T. Yoshitake, K. Inaba (Kyoto U.),
M. Yamauchi, T. Sato, R. Hatsuda, R. Fukuoka, Y. Hagiwara, Y. Umeki (Miyazaki U.),
K. Yamaoka (Nagoya U.),
Y. Kawakubo (LSU),
M. Sugizaki (NAOC)
report on behalf of the MAXI team:
The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at 2022-10-17T05:39:31 UT.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (116.859 deg, 39.409 deg) = (07 47 26, +39 24 32) (J2000)
with a statistical 90% C.L. elliptical error region
with long and short radii of 0.45 deg and 0.4 deg, respectively.
The roll angle of long axis from the north direction is 83.0 deg counterclockwise.
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
The X-ray flux averaged over the scan was 109 +- 30 mCrab
(4.0-10.0keV, 1 sigma error).
Without assumptions on the source constancy, we obtain a rectangular error
box for the transient source with the following corners:
(R.A., Dec) = (115.407, 38.740) deg = (07 41 37, +38 44 24) (J2000)
(R.A., Dec) = (116.206, 38.225) deg = (07 44 49, +38 13 30) (J2000)
(R.A., Dec) = (118.217, 40.060) deg = (07 52 52, +40 03 36) (J2000)
(R.A., Dec) = (117.412, 40.589) deg = (07 49 38, +40 35 20) (J2000)
There was no significant excess flux in the previous transit at 10/17 04:06 UT with an upper limit of 20 mCrab for each.