Logo image
返回
EP 250108a/SN 2025kg: Observations of the Most Nearby Broad-line Type Ic Supernova Following an Einstein Probe Fast X-Ray Transient
期刊文章   開放取用(OA)   同儕審查

EP 250108a/SN 2025kg: Observations of the Most Nearby Broad-line Type Ic Supernova Following an Einstein Probe Fast X-Ray Transient

Jillian C. Rastinejad, Andrew J. Levan, Peter G. Jonker, Charles D. Kilpatrick, Christopher L. Fryer, Nikhil Sarin, Benjamin P. Gompertz, Chang Liu, Rob A. J. Eyles-Ferris, Wen-Fai Fong, …
Astrophysical Journal Letters, 卷.988(1), L13
07/2025
DOI: https://doi.org/10.3847/2041-8213/ade7f9

摘要

Astronomy and Astrophysics Space and Planetary Science
With a small sample of fast X-ray transients (FXTs) with multiwavelength counterparts discovered to date, their progenitors and connections to γ-ray bursts (GRBs) and supernovae (SNe) remain ambiguous. Here, we present photometric and spectroscopic observations of SN 2025kg, the SN counterpart to the FXT EP 250108a. At z = 0.17641, this is the closest known SN discovered following an Einstein Probe (EP) FXT. We show that SN 2025kg’s optical spectra reveal the hallmark features of a broad-lined Type Ic SN. Its light-curve evolution and expansion velocities are comparable to those of GRB-SNe, including SN 1998bw, and two past FXT-SNe. We present JWST/NIRSpec spectroscopy taken around SN 2025kg’s maximum light, and find weak absorption due to He I 1.0830 μm and 2.0581 μm and a broad, unidentified emission feature at ∼4-4.5 μm. Further, we observe broadened Hα in optical data at 42.5 days that is not detected at other epochs, indicating interaction with H-rich material. From its light curve, we derive a 56 Ni mass of 0.2-0.6 M ⊙ . Together with our companion Letter, our broadband data are consistent with a trapped or low-energy (≲10 51 erg) jet-driven explosion from a collapsar with a zero-age main-sequence mass of 15-30 M ⊙ . Finally, we show that the sample of EP FXT-SNe supports past estimates that low-luminosity jets seen through FXTs are more common than successful (GRB) jets, and that similar FXT-like signatures are likely present in at least a few percent of the brightest Type Ic-BL SNe.

檔案與連結 (1)

url
https://doi.org/10.3847/2041-8213/ade7f9檢視
已出版(紀錄版本) 開放

相關連結

指標

1 檢視次數

詳細資料

Logo image