GRB 241113B: the first SVOM and EP gamma-ray burst A soft GRB likely seen on-axis, from soft X-rays to gamma-rays

@misc{adrien2026241113b,
  title = {{GRB 241113B: the first SVOM and EP gamma-ray burst A soft GRB likely seen on-axis, from soft X-rays to gamma-rays}},
  author = {D. Adrien and D. Turpin and T. Maiolino and F. Daigne and F. Piron and Z. -H. Yao and Q. Wu and C. -Y. Dai and A. V. Filippenko and B. Schneider and B. Kumar and B. Cordier and F. Cangemi and A. Coleiro and M. G. Bernardini and N. Dagoneau and Y. -L. Qiu and L. -P. Xin and H. -L. Li and H. Sun and X. -P. Xu and Z. -Y. Liu and M. -Q. Huang and M. -H. Zhang and W. Yuan and W. -K. Zheng and G. Mo and X. Liu and Y. Fang and G. -W. Du and S. Guillot and X. -W. Yu and R. Leticia Becerra and J. -Y. Wei and S. Basa and J. Wang and L. Bouchet and X. -H. Han and M. Brunet and C. Wu and S. Crepaldi and H. -B. Cai and O. Godet and Y. Xu and D. Götz and P. -P. Zhang and A. Saccardi and Y. -J. Xiao and S. Vergani and S. -N. Zhang and S. -L. Xiong and Y. -W. Dong and J. -T. Liu},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2610.41005},
  eprint = {2610.41005},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2610.41005},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - GRB 241113B: the first SVOM and EP gamma-ray burst A soft GRB likely seen on-axis, from soft X-rays to gamma-rays
AU  - D. Adrien
AU  - D. Turpin
AU  - T. Maiolino
AU  - F. Daigne
AU  - F. Piron
AU  - Z. -H. Yao
AU  - Q. Wu
AU  - C. -Y. Dai
AU  - A. V. Filippenko
AU  - B. Schneider
AU  - B. Kumar
AU  - B. Cordier
AU  - F. Cangemi
AU  - A. Coleiro
AU  - M. G. Bernardini
AU  - N. Dagoneau
AU  - Y. -L. Qiu
AU  - L. -P. Xin
AU  - H. -L. Li
AU  - H. Sun
AU  - X. -P. Xu
AU  - Z. -Y. Liu
AU  - M. -Q. Huang
AU  - M. -H. Zhang
AU  - W. Yuan
AU  - W. -K. Zheng
AU  - G. Mo
AU  - X. Liu
AU  - Y. Fang
AU  - G. -W. Du
AU  - S. Guillot
AU  - X. -W. Yu
AU  - R. Leticia Becerra
AU  - J. -Y. Wei
AU  - S. Basa
AU  - J. Wang
AU  - L. Bouchet
AU  - X. -H. Han
AU  - M. Brunet
AU  - C. Wu
AU  - S. Crepaldi
AU  - H. -B. Cai
AU  - O. Godet
AU  - Y. Xu
AU  - D. Götz
AU  - P. -P. Zhang
AU  - A. Saccardi
AU  - Y. -J. Xiao
AU  - S. Vergani
AU  - S. -N. Zhang
AU  - S. -L. Xiong
AU  - Y. -W. Dong
AU  - J. -T. Liu
PY  - 2026
DA  - 2026/10/29
PB  - arXiv
DO  - 10.48550/arxiv.2610.41005
UR  - https://arxiv.org/abs/2610.41005
AB  - In 2024, two new missions were launched to detect high-energy transients. EP and SVOM aim to observe soft transients from X-ray rich gamma-ray bursts (XRR), X-ray flashes (XRF), to fast X-ray transients (FXT). GRB 241113B, the first soft gamma-ray burst (GRB) jointly detected by EP and SVOM from soft X-rays to gamma-rays (0.5--1000~keV). GRB 241113B has an E^obs_peak ≈ 35 keV and a redshift (z) likely between 0.5 and 3.5, with T_90,γ ≈ 42~s (4--30~keV). This burst can be classified as either an XRR or XRF, depending on the fluence ratio used. The afterglow is achromatic and featureless with a normal decay (α≈ −1.40). The prompt emission does not satisfy the shock-breakout relation, and thus a geometry comprised of a jet is preferred. However, the afterglow fitting favors a jet viewed on-axis dominated by synchrotron emission due to electrons in a slow cooling regime, interacting with a wind medium. The bulk Lorentz factor (Γ) indicates that the motion of the jet is ultrarelativistic (Γ_0>100), which discards the dirty fireball model. Hence, the jet baryon loading should be compatible with that of classical GRBs (C-GRBs). The prompt spectral properties of GRB 241113B (α, E^obs_peak, E_γ,iso) are comparable to those of XRFs/XRRs and are in the continuity of the C-GRB distributions, setting it apart from the extragalatic FXT population solely detected by EP. Hence, the SVOM mission, with the benefit brought by the instrument ECLAIRs with its high sensitivity and low energy threshold (at 4keV), is able to detect the potential γ-ray counterpart of soft transients also observed by EP and help to differentiate them from FXTs. The latter show the interest of the joint operation of both missions to better study the landscape of soft transients.
ER  -