GRB 241107A

D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin,
A. Tsvetkova,  M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:

The short GRB 241107A (SVOM/GRM detection: Wang et al., GCN 38125
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 ;
INTEGRAL/IBIS/PICsIT detection: Rodi et al., GCN 38164
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 ;
IPN triangulation: Kozyrev et al., GCN 38165
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 ;
INTEGRAL IBIS localization: Mereghetti et al., GCN 38172
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 ;
Swift/BAT candidate arcminute localization: DeLaunay et al.: GCN 38177
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 )
triggered Konus-Wind (KW) at T0=84602.493 s UT (23:30:02.493).

The burst light curve starts with a bright, multi-peaked emission pulse
with a duration of ~0.028 s, which is followed by a weaker, decaying emission.
The total duration of the burst is ~0.160 s.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB241107_T84602/

As observed by Konus-Wind, the burst had
a total fluence of 1.43(-0.33, +0.13)x10^-6 erg/cm^2 and
a 16-ms peak energy flux, measured from T0-0.096 s,
of 3.6 (-1.2, +0.2)x10^-5 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).

Since the bulk of the burst emission was detected before
the trigger, the spectral analysis was performed using
the KW 3-channel light curve data.

The time-averaged spectrum of the burst (measured from T0-0.112 s to T0+0.048 s)
is best fit by a blackbody (BB) function with kT(BB) = 193 (-18, +20) keV.
This spectrum can be also described by a power law with
exponential cutoff (CPL) model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with a hard photon index alpha = 1.32(-1.09,+2.7) and Ep = 760(-91,+390) keV.

The spectrum of the initial pulse alone (measured from T0-0.112 s to T0-0.080 s)
is best described by a blackbody function with kT(BB) = 251 (-31, +38) keV.
The fluence in this pulse is 1.15(-0.38, +0.06)x10^-6 erg/cm^2, or ~80%
of the total fluence.


All the quoted errors are estimated at the 68% confidence level.
All the presented results are preliminary.

James DeLaunay (PSU), Aaron Tohuvavohu (Caltech), Samuele Ronchini (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC)  report:

Swift/BAT did not localize GRB 241107A onboard (T0:  2024-11-07T23:30:00.1 UTC, SVOM/GRM GCN 38125
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 ).

3 seconds of TTE data is available covering the time of this burst, associated with BAT failed trigger #1266248, as the burst triggered BAT's rate trigger algorithm, but failed to localize the burst onboard. There is no long duration GUANO data available for this burst due to lack of prompt notice from other instruments.

The burst is seen clearly in the BAT rates light-curve, but we fail to recover it in an image. 

The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), typically requires ~40 s of off-time TTE data to properly fit the background, but here we attempt to approximate the background model with ~2.5 s of TTE data around the burst. 

NITRATES detects the burst in a 0.2 s analysis time bin with a sqrt(TS) of 35.2. 
An arcminute localization candidate is found with a DeltaLLHPeak of 10.3 and DeltaLLHOut of 2.5. 

Due to limited data, nonstandard fitting was used, so the position is independently not highly confident, but matches both the IPN (GCN 38165
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 ) and INTEGRAL/IBIS (GCN 38172
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 ) localizations.

See Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief descriptions and interpretations of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut.

The BAT candidate position is
RA, Dec = 111.325, -24.487 deg which is
   RA(J2000)  = 07h 25m 18.0s
   Dec(J2000) = -24 29′ 13.2″
with an estimated uncertainty of 4 arcmin radius.

A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin
on behalf of the HEND/Mars Odyssey team,

D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia,
and T. Cline on behalf of the Konus-Wind team,

S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu
on behalf of the Swift-BAT team,

Y. Zhang, C. Wang, S. Xiong, J. Wei, and B. Cordier
on behalf of the SVOM-GRM 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

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 hard-spectrum, short-duration GRB 241107A
(SVOM-GRM detection: Wang et al., GCN 38125
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 ;
INTEGRAL-IBIS/PICsIT detection: Rodi et al., GCN 38164
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 )
was detected by SVOM (GRM), Konus-Wind, INTEGRAL (SPI-ACS),
and Swift (BAT) at about 84600 s UT (23:30:00).
The burst was inside the coded field of view of the BAT, but
there was no BAT trigger.

We have triangulated it to a preliminary, 
3 sigma error box, whose coordinates are:
 ---------------------------------------------
  RA(2000), deg                 Dec(2000), deg
 ---------------------------------------------
 Center:
  113.377 (07h 33m 30s) -22.582 (-22d 34' 56")
 Corners:
  107.205 (07h 08m 49s) -27.689 (-27d 41' 21")
  114.251 (07h 37m 00s) -21.868 (-21d 52' 04")
  117.499 (07h 50m 00s) -18.325 (-18d 19' 30")
  112.449 (07h 29m 48s) -23.318 (-23d 19' 03")
 ---------------------------------------------
The error box area is 1.13 sq. deg, and its maximum
dimension is 13.3 deg (the minimum one is 9 arcmin).
The Sun distance was 100 deg.

This localization may be improved.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB241107_T84602/IPN/
The HEALPix triangulation maps are in units of probability density.

The Konus-Wind time history and spectrum will be given
in a forthcoming GCN Circular. 

J. Rodi, P. Ubertini, A. Bazzano, and L. Natalucci - INAF-IAPS 

We report on the INTEGRAL/IBIS/PICsIT detection of GRB 241107A first reported by SVOM/GRB (Wang et al. GCN 38125
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 ).  In the 200-2600 keV energy range, the burst duration is ~0.16 s with a total significance of ~34.4 sigma.  The significance in each of the 8 energy channels ranges from ~7.5 - 10 sigma.  Further detailed analysis is ongoing. 

SVOM/GRM team: Chen-Wei Wang, Wen-Jun Tan, Shi-Jie Zheng, Yong-Wei Dong, Jiang-Tao Liu, Jian-Chao Sun, Yue Huang, Jiang He, Min Gao, Hao-Xuan Guo, Lu Li, Yong-Ye Li, Hong-Wei Liu, Xin Liu, Hao-Li Shi, Li-Ming Song, You-Li Tuo, Wen-Long Zhang, Hao-Xi Wang, Jin Wang, Jin-Zhou Wang, Ping Wang, Rui-Jie Wang, Yu-Xi Wang, Bo-Bing Wu, Shao-Lin Xiong, Jian-Ying Ye, Yi-Tao Yin, Wen-Hui Yu, Fan Zhang, Li Zhang, Peng Zhang, Shuang-Nan Zhang, Yan-Qiu Zhang, Yan-Ting Zhang, Shu-Min Zhao, Xiao-Yun Zhao, Chao Zheng (IHEP), Maria-Grazia Bernardini (LUPM/INAF-OAB), Laurent Bouchet (IRAP), David Corre (CEA), Tais Maiolino (LUPM), Frédéric Piron (LUPM), Stéphane Schanne (CEA), Jingwei Wang (IAP), JeanLuc Attéia (IRAP)

SVOM JSWG: Jian-Yan Wei (NAOC), Bertrand Cordier (CEA), Shuang-Nan Zhang (IHEP), Stéphane Basa (LAM), Arnaud Claret (CEA), Zi-Gao Dai (USTC), Frédéric Daigne (IAP), Jin-Song Deng (NAOC), Olivier Godet (IRAP),  Andrea Goldwurm (APC), Diego Götz (CEA), Xu-Hui Han (NAOC), Cyril Lachaud (APC), En-Wei Liang (GXU), Yu-Lei Qiu (NAOC), Susanna Vergani (Obs.Paris), Jing Wang (NAOC), Chao Wu (NAOC), Li-Ping Xin (NAOC),  Shao-Lin Xiong (IHEP), Bing Zhang  (UNLV)

report on behalf of the SVOM team:

During the commissioning phase, the SVOM/GRM was triggered in-flight by GRB 241107A at 2024-11-07T23:30:00.100 UT (T0).

The real-time alert data and light curves of SVOM/GRM were downlinked to the ground through the VHF system with low latency. The GRM light curve shows that this burst consists of a single pulse followed by a tail with a T90 of 0.5 +0.1/-0.1 s.

The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. GRM is developed by the Institute of High Energy Physics (IHEP) of CAS.

The SVOM point of contact for this burst is: Chen-Wei Wang (IHEP)(cwwang@ihep.ac.cn)