GRB 241120A
GCN Circular 38307
Subject
GRB 241120A: GRBAlpha detection
Date
2024-11-25T12:53:07Z (a year ago)
From
Andras Pal at Konkoly Observatory <apal@szofi.net>
Via
Web form
A. Pal (Konkoly Observatory), M. Dafcikova, J. Ripa, M. Kolar, N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Duriskova, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal, A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.
The long-duration GRB 241120A (Fermi/GBM detection: GCN 38279; INTEGRAL/SPI-ACS detection: GCN 38280; CALET/CGBM detection: GCN 38295; Konus/Wind detection: GCN 38297) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; https://ui.adsabs.harvard.edu/abs/2023A%26A...677A..40P/abstract).
The detection was confirmed at the peak time 2024-11-20 05:54:00.1 UTC. The T90 duration measured by GRBAlpha is 3 s and the overall significance during T90 reaches 8 sigma.
The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB241120A_GCN.pdf
All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/
GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume.
GCN Circular 38297
Subject
Konus-Wind detection of GRB 241120A
Date
2024-11-22T14:38:03Z (a year ago)
From
Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>
Via
Web form
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 241120A
(Fermi-GBM detection: Fermi GBM team, GCN 38279;
Hamburg & Meegan, GCN 38285;
INTEGRAL (IBIS/ISGRI) detection: Gotz et al., GCN 38280;
CALET (CGBM) detection: Cherry et al., GCN 38295)
triggered Konus-Wind at T0=21240.717 s UT (05:54:00.717).
The burst light curve shows a single pulse,
which starts at ~T0-1.9 s and has a total duration of ~2.9 s.
The emission is seen up to ~2 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB241120_T21240/
As observed by Konus-Wind, the burst
had a fluence of 3.55(-0.48,+0.59)x10^-6 erg/cm2,
and a 64-ms peak flux, measured from T0+0.372 s,
of 4.98(-1.17,+1.30)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+8.448 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.91(-0.29,+0.34)
and Ep = 267(-56,+95) keV (chi2 = 80/78 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.6
(chi2 = 80/77 dof).
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
GCN Circular 38296
Subject
GRB241120A: OHP/T193 optical observations
Date
2024-11-22T12:21:38Z (a year ago)
From
Christophe Adami at LAM <christophe.adami@lam.fr>
Via
Web form
C. Adami (LAM/Pytheas/AMU), M. Dennefeld (IAP), S. Basa (LAM/OHP/Pytheas/AMU) report on behalf of a
larger collaboration:
We observed the field of GRB241120A (Gotz et al., GCN 38280; Fermi GRM team, GCN 38279; Hamburg
et al., GCN 38285; Pankov et al., GCN 38291; Cherry et al., GCN 38295) using the T193cm telescope
at Observatoire de Haute-Provence (France) equipped with the MISTRAL spectro-imager. Four exposures
were obtained in the r-band (300s + 3x420s) from 2024 21 November 04:39 UT to 2024 21 November
05:05 UT (~+23h after detection) with two positions on the sky (position "1" for exposures 1 and
4, and position "2" for exposures 2 and 3) separated by a dithering of ~10arcsec. The moon was at an
illumination of ~68% and at a distance of 56deg from target.
The combined frame has a detection upper limit of r~22.5+/-0.6 (5sigma limit). The photometric
calibration was performed using objects from the PanSTARRS catalog. The magnitudes are not
corrected for Galactic extinction.
There is no clear additional objects in the MISTRAL image as compared with the PanStarrs r-band
image except a source at 12:57:06.0 +52:08:26.6 (r~22.2+/-0.2). This source (apparently extended)
is however only present in two of the four exposures we performed (position "2" exposures) and is
possibly an internal reflection within the instrument due to the intense Moon illumination. More
observations are requested to check this point.
We also checked the candidate of Pankov et al. We clearly detect this object and measured a
magnitude of r~20.40+/-0.08 23h after the original detection. This object is also present in the
PanStarrs r-band catalog at r~20.39+/-0.02. If this was the transient, it was back to its initial
magnitude 0.96 days after detection. This would be in good agreement with the light curve proposed by
Pankov et al.
We acknowledge the excellent support from Observatoire de Haute-Provence, in particular Jean Pierre
Troncin and the SOPHIE observer Aleyna Adamson.
GCN Circular 38295
Subject
GRB 241120A: CALET Gamma-Ray Burst Monitor detection
Date
2024-11-22T06:14:13Z (a year ago)
From
Yuta Kawakubo at Aoyama Gakuin University <kawakubo@phys.aoyama.ac.jp>
Via
Web form
M. L. Cherry (LSU), A. Yoshida, T. Sakamoto, S. Sugita,
Y. Kawakubo (AGU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA),
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 241120A (Fermi GBM Final Real-time Localization: Fermi GBM
team, GCN Circ. 38279; a long GRB detected by INTEGRAL: Gotz et al.,
GCN Circ. 38280; Fermi GBM Observation, Hamburg et al., GCN Circ. 38285)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 05:54:00.493 UTC
on 20 November 2024
(https://cgbm.calet.jp/cgbm_trigger/flight/1416117245/index.html).
The burst signal was seen by all CGBM detectors. Because of a problem with
the ground alert processing script, the GCN notice was not distributed
automatically for this event.
The burst light curve shows a single emission episode that starts
at T-3.0 sec, peaks at T+0.1 sec, and ends at T+0.8 sec.
The T90 and T50 durations measured by the SGM data are 2.9 ± 0.5 sec
and 0.8 ± 0.3 sec (40-1000 keV), respectively.
The ground-processed light curve is available at
https://cgbm.calet.jp/cgbm_trigger/ground/1416117245/
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.
GCN Circular 38291
Subject
GRB 241120A: Mondy and AbAO optical observations
Date
2024-11-21T16:55:29Z (a year ago)
From
XXXX at IKI <alex@cgrsmx.iki.rssi.ru>
Via
legacy email
N. Pankov (HSE, IKI), A. Pozanenko (IKI), E. Klunko (ISTP), R. Ya. Inasaridze (AbAO), V. Aivazyan (AbAO) report on behalf of IKI-GRB-FuN:
We observed the field of GRB 241120A detected (The Fermi GBM team, GCN 38279; Gotz et al., GCN 38280) with AZT-33IK telescope of Sayan (Mondy) observatory, and AS-32 telescope of Abastumani observatory (AbAO). The observations started at Mondy on 2024-11-20 at 20:01 UT, i.e. ~0.6 days since trigger. Within the localization circle of INTEGRAL (Gotz et al., GCN 38280) we do not find any evident candidates in comparison with known catalogues. However, there is a source in our observations at the coordinates of (J2000) RA=12:57:04.3 Dec=+52:08:45.8 with uncertainty of 0.2 arcses in both coordinates for which it can be assumed that the source is showing marginal decreasing of brightness.
The source is presented at least in PS1, SDSS and DESI.
Preliminary photometry of the source is as follows:
Date UT_start Exp_time t-T0 Filter OT Err UL
(s) (mid, days) (3sigma)
2024-11-20 20:01:27 28*120 0.60798 R 19.85 0.10 22.6 AZT-33IK
2024-11-20 23:12:31 56*60 0.74066 R 20.1 0.3 20.6 AS-32
The magnitudes were calibrated with nearby USNO-B1.0 stars (R2 magnitudes) and not corrected for the Galactic extinction.
The source is 53 arcsec from the centre of IBIS/ISGRI localization. The catalogued source is a galaxy with estimated photo-z = 0.36 and brightness of r=20.2 (SDSS DR16), and photo-z = 0.38 (DESI). The source brightness in PS1 is r = 20.69. We may suggest the source is a possible candidate in the afterglow of GRB 241120A.
GCN Circular 38285
Subject
GRB 241120A: Fermi GBM Observation
Date
2024-11-20T20:31:12Z (a year ago)
From
rhamburg@usra.edu
Via
Web form
R. Hamburg (USRA) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:
"At 05:53:58.54 UT on 20 November 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 241120A (trigger 753774843/241120246),
which was also detected by INTEGRAL/IBAS (Gotz et al. 2024, GCN 38280).
The Fermi GBM on-ground location is consistent with the INTEGRAL position.
The angle from the Fermi LAT boresight is about 39 degrees.
The GBM light curve consists of a single emission episode with a duration (T90)
of about 3.2 s (50-300 keV). The time-averaged spectrum
from T0-0.5 to T0+3.3 s is best fit by a Band function with
Epeak = 181 +/- 13, alpha = -0.3 +/- 0.1, and beta = -2.4 +/- 0.2.
The event fluence (10-1000 keV) in this time interval is
(3.6 +/- 0.1)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.7 s in the 10-1000 keV band is 12.3 +/- 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/"
GCN Circular 38280
Subject
GRB241120A: a long GRB detected by INTEGRAL
Date
2024-11-20T07:01:13Z (a year ago)
From
Diego Gotz at CEA <diego.gotz@cea.fr>
Via
Web form
D.Gotz (CEA, Saclay), S.Mereghetti (INAF, IASF-Milano), C.Ferrigno, E.Bozzo, V.Savchenko (ISDC, Versoix), L.Ducci (IAAT, Germany and ISDC, Versoix) and J.Borkowski (CAMK, Torun) report:
a gamma ray burst lasting about 4 s has been detected by IBAS in the IBIS/ISGRI data at 05:53:58 UT of 2024 November 20.
The refined coordinates (J2000) are:
R.A.= 194.2908 deg,
DEC.= 52.1504 deg
with an uncertainty of 1 arcmin (90% c.l.).
A preliminary analysis gives a peak flux of about 2 ph/cm2/s (20-200 keV, 1-s integration time) and a fluence in the same energy range of about 1.3e-06 erg/cmsq.
This burst has also been detected by Fermi/GBM (GCN 38279), and its position is at 2.7° from the Fermi reported position.
A plot of the light curve will be posted at
http://ibas.iasf-milano.inaf.it/IBAS_Results.html
GCN Circular 38279
Subject
GRB 241120A: Fermi GBM Final Real-time Localization
Date
2024-11-20T06:04:29Z (a year ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
Via
email
The Fermi GBM team reports the detection of a likely LONG GRB
At 05:53:58 UT on 20 Nov 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 241120A (trigger 753774843.543556 / 241120246).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 192.5, Dec = 49.7 (J2000 degrees, equivalent to J2000 12h 50m, 49d 42'), with a statistical uncertainty of 1.2 degrees.
The angle from the Fermi LAT boresight is 36.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241120246/quicklook/glg_skymap_all_bn241120246.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241120246/quicklook/glg_healpix_all_bn241120246.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn241120246/quicklook/glg_lc_medres34_bn241120246.gif