发表机构
Aix Marseille University; CNRS; CNES; LAM; Radboud University; University of Warwick; Kavli Institute for Cosmology, University of Cambridge; Institute of Astronomy, University of Cambridge; School of Physics and Astronomy, University of Birmingham; Institute for Gravitational Wave Astronomy, University of Birmingham; Université Paris-Saclay; Université Paris Cité; CEA; AIM; Cosmic Dawn Center (DAWN); Niels Bohr Institute, University of Copenhagen; School of Physics and Centre for Space Research, University College Dublin; INAF – Osserva（艾克斯-马赛大学; 法国国家科学研究中心; 法国国家空间研究中心; 拉格朗日天体物理实验室; 拉德堡德大学; 华威大学; 剑桥大学卡弗里宇宙学研究所; 剑桥大学天文研究所; 伯明翰大学物理与天文学院; 伯明翰大学引力波天文学研究所; 巴黎萨克雷大学; 巴黎西岱大学; 法国原子能和替代能源委员会; 天体物理学和分子相互作用实验室; 宇宙黎明中心; 哥本哈根大学尼尔斯玻尔研究所; 都柏林大学学院物理系与太空研究中心; 意大利国家天体物理研究所观测站）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用JWST/NIRSpec数据，在GRB 240825A位置探测到与SN 1998bw相似的尘埃遮蔽超新星，确证其大质量恒星起源，并展示了JWST在富尘环境中发现超新星的能力。
AI 中文摘要
最近的观测对基于持续时间的伽马射线暴（GRB）分类提出了挑战，使得探测到与之相关联的超新星（SN）或千新星对于最终确定其前身天体至关重要。我们研究了红移$z=0.659$的GRB 240825A的起源，其瞬时辐射给出了关于并合或坍缩星起源的相互矛盾的指示，且在地面深场观测中未探测到超新星。我们分析了爆发后66.5天（静止系40.1天）获得的JWST/NIRSpec观测数据。我们利用二维光谱的逐像素分解识别出一个超新星信号，并通过联合建模宿主星系和瞬变辐射将其分离出来。我们根据余辉光谱能量分布约束视线消光，并通过宽带测光和星云发射线表征宿主星系。尽管视线方向尘埃较多（$A_V=1.37\pm0.08$星等），且有2175 Å吸收特征的初步证据，宿主星系较亮（$M_B=-20.5$ AB星等），但我们还是在GRB位置识别出一个点状源，其宽谱特征与SN 1998bw相似。该超新星贡献了NIRSpec通量的约10%-15%，而在同一时刻的地面光学图像中，它仅贡献总通量的约1%。其消光校正后的光度与SN 1998bw相当，但仍对宿主星系扣除和模板假设敏感。宿主星系是一个延展的、尘埃较多的恒星形成星系，$\log(M_\star/M_\odot)=10.12\pm0.05$，恒星形成率SFR $=5.88\pm1.60\\,{\rm M_\odot\\,yr^{-1}}$，金属丰度超太阳，$12+\log({\rm O/H})=8.87\pm0.04$，高于通常观测到的坍缩星GRB宿主星系金属丰度。尘埃遮蔽超新星的探测确证了GRB 240825A的大质量恒星起源，并表明JWST能够揭示此前在很大程度上无法探测的、处于尘埃且化学富集环境中的超新星。
英文摘要
Recent observations have challenged the duration-based classification of gamma-ray bursts (GRBs), making the detection of an associated supernova (SN) or kilonova crucial for conclusively identifying their progenitors. We investigate the origin of GRB 240825A at $z=0.659$, whose prompt emission gave conflicting indications of a merger or collapsar origin and for which no SN was detected in deep ground-based observations. We analyze JWST/NIRSpec observations obtained 66.5 days (40.1 days in the rest frame) after the burst. We identify a SN signal using a pixel-by-pixel decomposition of the 2D spectrum and isolate it by jointly modeling the host and transient emission. We constrain the line of sight extinction from the afterglow spectral energy distribution and characterize the host through broadband photometry and nebular emission lines. Despite a dusty line of sight ($A_V=1.37\pm0.08$ mag), with tentative evidence of a 2175 Å bump, and a bright host galaxy ($M_B=-20.5$ AB mag), we identify a point-like source at the GRB position with broad spectral features similar to those of SN 1998bw. The SN contributes $\sim$10-15% of the NIRSpec flux and would contribute only $\sim$1% of the total flux in a ground-based optical image at the same epoch. Its extinction-corrected luminosity is comparable to SN 1998bw, although it remains sensitive to the host subtraction and template assumptions. The host is an extended, dusty, star-forming galaxy with $\log(M_\star/M_\odot)=10.12\pm0.05$, SFR $=5.88\pm1.60\,{\rm M_\odot\,yr^{-1}}$, and a super-solar metallicity of $12+\log({\rm O/H})=8.87\pm0.04$, above the metallicity typically observed for collapsar GRB hosts. The detection of a dust-obscured SN firmly establishes the massive-star origin of GRB 240825A and shows that JWST can uncover SNe in dusty, chemically enriched environments that were previously largely inaccessible.
Comments15 pages, 10 figures. Submitted to A&A
