GRB 240101C
GCN Circular 35451
Subject
GRB 240101C: Fermi GBM Final Localization
Date
2024-01-02T03:31:02Z (a year ago)
From
Bagrat Mailyan at Florida Tech <mbagrat@gmail.com>
Via
Web form
The Fermi GBM team reports the detection of a likely SHORT GRB
"At 12:57:23.76 UT on 01 January 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240101C (trigger 725806648/240101540).
The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 4.73, Dec = 30.46 (J2000 degrees, equivalent to J2000 0h 18m, +30d 27'),
with a statistical uncertainty of 3.33 degrees.
The angle from the Fermi LAT boresight is 69 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240101540/quicklook/glg_skymap_all_bn240101540.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/bn240101540/quicklook/glg_healpix_all_bn240101540.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240101540/quicklook/glg_lc_medres34_bn240101540.gif"
GCN Circular 35459
Subject
GRB 240101C: GRBAlpha detection
Date
2024-01-02T15:28:27Z (a year ago)
From
Marianna Dafčíková at Masaryk University <500025@mail.muni.cz>
Via
Web form
M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Kolar, 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 short-duration GRB 240101C (Fermi/GBM detection: GCN 35451; INTEGRAL/SPI-ACS peak detection at 2024-01-01 ~12:57:24 UT) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; arXiv:2302.10048).
The detection was confirmed at the peak time 2024-01-01 12:57:24 UTC. The T90 duration measured by GRBAlpha is 1 s and the overall significance during T90 reaches 4.9 sigma in the 120-400 keV band.
The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB240101C_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 35478
Subject
GRB 240101C: AstroSat CZTI detection
Date
2024-01-04T04:38:33Z (a year ago)
From
Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>
Via
Web form
P. K. Navaneeth (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 short-duration GRB 240101C which was also detected by Fermi-GBM (Fermi GBM team, GCN Circ. 35451), and GRBAlpha (Dafcikova et al., GCN Circ. 35459).
The source was detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2024-01-01 12:57:23.80 UTC. The measured peak count rate associated with the burst is 881 (+732, -43) counts/s above the background in the combined data of all quadrants, with a total of 69 (+31, -22) counts. The local mean background count rate was 331 (+13, -43) counts/s. Using cumulative rates, we measure a T90 of 0.13 (+0.06, -0.04) s.
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.
CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb
GCN Circular 35482
Subject
GRB 240101C: Swift/BAT-GUANO detection of a short burst
Date
2024-01-05T02:17:35Z (a year ago)
From
Jimmy DeLaunay at Penn State <delauj2@gmail.com>
Via
Web form
James DeLaunay (PSU), Gayathri Raman (PSU), Samuele Ronchini (PSU), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report:
Swift/BAT did not localize GRB 240101C onboard (T0: 2024-01-01T12:57:23.76 UTC, Fermi GBM Trig 725806648, GRBAlpha GCN 35459, AstroSat CZTI GCN 35478).
The Fermi notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1).
Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground.
The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), performed on the temporal window [T0-20 s, T0+20 s], detects the burst with a sqrt(TS) of 11.2 in a 0.128 s analysis time bin, starting at T0 s.
NITRATES results, independently, are ambiguous with respect to whether this burst originates from in or outside the BAT coded FOV, with a DeltaLLHOut of 4.2.
See Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief descriptions and interpretation of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut.
GUANO is a fully autonomous, extremely low latency, spacecraft
commanding pipeline designed for targeted recovery of BAT event mode
data around the times of compelling astrophysical events to enable
more sensitive GRB searches.
A live reporting of Swift/BAT event data recovered by GUANO can be
found at: https://www.swift.psu.edu/guano/
GCN Circular 35488
Subject
GRB GRB240101C: Fermi GBM observation
Date
2024-01-05T18:41:54Z (a year ago)
From
sumanbala2210@gmail.com
Via
Web form
S. Bala (USRA), B. Mailyan (Florida Tech) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:
"At 12:57:23.76 UT on 01 January 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240101C (trigger 725806648/240101540),
which was also detected by the Swift/BAT-GUANO (J. DeLaunay et. al. 2023, GCN 35482),
GRBAlpha (Dafcikova et al. GCN Circ. 35459) and AstroSat CZTI (Navaneeth et al.
GCN 35478). The Fermi GBM on-ground calculated location, using the Fermi GBM
trigger data has been reported at GCN 35451.
The angle from the Fermi LAT boresight at the GBM trigger time is 69.0 degrees.
The GBM light curve consists of one very short peak
with a duration (T90) of about 0.35 s (50-300 keV).
The time-averaged spectrum from T0-0.064 s to T0+0.256 s is
best fit by a Comptonized Epeak function with Epeak = 286.4 +/- 21.8 keV, and
alpha = 0.10 +/- 0.14.
The event fluence (10-1000 keV) in this time interval is
(1.19 +/- 0.07)E-6 erg/cm^2. The 64-msec peak photon flux measured
starting from T0 in the 10-1000 keV band
is 460.9 +/- 77.4 ph/s/cm^2.
A Band function fits the spectrum equally well
with Epeak= 242.7 +/- 28.8 keV, alpha = 0.30 +/- 0.20 and beta = -2.50 +/- 0.39.
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 35489
Subject
IPN triangulation of GRB 240101C (short)
Date
2024-01-05T19:17:11Z (a year ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
Via
legacy email
D. Svinkin, D. Frederiks, A. Ridnaia, A. Lysenko,
and T. Cline on behalf of the Konus-Wind team,
A. Goldstein, M. S. Briggs, C. Wilson-Hodge,
and E. Burns on behalf of the Fermi GBM team,
E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
and
S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu
on behalf of the Swift-BAT team, report:
The short-duration GRB 240101C
(Fermi-GBM detection: The Fermi GBM team, GCN 35451;
Bala et al., GCN 35488;
GRBAlpha detection: Dafcikova et al., GCN 35459;
AstroSat-CZTI detection: Navaneeth et al., GCN 35478;
Swift-BAT/GUANO detection: DeLaunay et al., GCN 35482)
has been detected by Fermi (GBM trigger 725806648), Swift (BAT), GRBAlpha, Konus-Wind, INTEGRAL (SPI-ACS), and AstroSat (CZTI),
so far, at about 46644 s UT (12:57:24).
The burst was outside the coded field of view of the BAT.
We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
---------------------------------------------
RA(2000), deg Dec(2000), deg
---------------------------------------------
Center:
358.487 (23h 53m 57s) +28.743 (+28d 44' 36")
Corners:
0.797 (00h 03m 11s) +24.032 (+24d 01' 56")
1.127 (00h 04m 30s) +23.926 (+23d 55' 33")
355.725 (23h 42m 54s) +33.705 (+33d 42' 18")
355.318 (23h 41m 16s) +33.852 (+33d 51' 06")
---------------------------------------------
The error box area is 2.5 sq. deg and its maximum
dimension is 11.15 deg (the minimum one is 14 arcmin).
The Sun distance was 90 deg.
This localization may be improved.
The IPN localization is consistent with, but reduces the area of,
the Fermi-GBM localizations.
A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB240101_T46643/IPN/
GCN Circular 35508
Subject
Konus-Wind detection of GRB 240101C
Date
2024-01-09T15:07:11Z (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 short-duration GRB 240101C
(Fermi-GBM detection: The Fermi GBM team, GCN 35451;
Bala et al., GCN 35488;
GRBAlpha detection: Dafcikova et al., GCN 35459;
AstroSat-CZTI detection: Navaneeth et al., GCN 35478;
Swift-BAT/GUANO detection: DeLaunay et al., GCN 35482;
IPN triangulation: Svinkin et al., GCN 35489)
triggered Konus-Wind at T0=46643.329 s UT (12:57:23.329).
The burst light curve shows a single pulse
which starts at ~T0-0.1 s and has a total duration of ~0.3 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/GRB240101_T46643/
As observed by Konus-Wind, the burst
had a fluence of 1.39(-0.19,+0.21)x10^-6 erg/cm2,
and a 16-ms peak flux, measured from T0-0.002 s,
of 1.57(-0.41,+0.43)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+0.256 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 = -0.19(-0.41,+0.52)
and Ep = 326(-56,+80) keV (chi2 = 15/22 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.4
(chi2 = 15/21 dof).
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.