AI 中文总结
本研究通过高分辨率光谱分析Ia型超新星2025rbs，发现其前身星周围无近距星周物质，支持双简并CO白矮星双星的前身星场景。
AI 中文摘要
我们呈现了在邻近星系NGC 7331中发现的Ia型超新星（SN）2025rbs的高分辨率光谱时序数据。利用利克天文台的Automated Planet Finder（APF）以及双子座北座的MAROON-X/IGRINS-2设备，在最大光度 epoch 前后-5至15天的范围内获取了 echelle 光谱。我们证认出沿视线方向的数个未饱和Na I D吸收成分，但所有这些成分均未表现出时间变化。我们测量了观测到的5780埃附近弥散星际带的等效宽度，并约束了SN 2025rbs视线方向的消光量为$A_V = 0.64\\,\pm\\,0.32$星等，对应中度红化量$E(B-V) = 0.21\\,\pm\\,0.10$星等（假设$R_V = 3.1$）。观测到的Ca II H & K星际吸收在速度空间大致与Na I D重合，表明它们有共同起源。对这些宿主云内Na与Ca气体柱密度的定量比较（$N_{Na I D}$ / $N_{Ca II}$量级为1），否定了它们起源于银晕气体，转而支持其为NGC 7331星际气体产生的吸收。所有观测到的吸收特征的时间不变性表明，SN 2025rbs的前身星系统周围不存在近距星周物质（$\lesssim 10^{16}$厘米）。这支持SN 2025rbs的前身星场景为周围几乎没有星周气体的情况，与双简并CO白矮星双星系统一致。
英文摘要
We present a high-resolution spectral time series of the Type Ia supernova (SN) 2025rbs discovered in the nearby galaxy NGC 7331. The Automated Planet Finder (APF) at Lick Observatory and the MAROON-X/IGRINS-2 at Gemini North were used to obtain echelle spectra between -5 and 15 days with respect to the epoch of maximum light. Several unsaturated NaID absorption components along the line of sight are identified, but there is no evidence of time variance in any of them. We measure the equivalent width of the observed diffuse interstellar band around 5780 A and constrain the extinction along the line of sight to SN 2025rbs as $A_V = 0.64\,\pm\,0.32$ mag, corresponding to a moderate reddening of $E(B-V) = 0.21\,\pm\,0.10$ mag (assuming $R_\mathrm{V}$ = 3.1). The observed Ca II H & K interstellar absorption roughly traces NaID in velocity space, suggesting a common origin. Quantitative comparisons between the column densities of Na and Ca gas in these host clouds ($N_{NaID}$ / $N_{Ca II}$ of order unity) argue against their origin in the Galactic halo gas and instead support absorption due to the interstellar gas of NGC 7331. Time invariance of all the observed absorption features suggests a lack of nearby circumstellar material ($\lesssim$ 10$^{16}$ cm) around the progenitor system of SN 2025rbs. This supports a progenitor scenario for SN 2025rbs with minimal ambient circumstellar gas, consistent with a double-degenerate CO white dwarf binary system.
CommentsSubmitted to ApJ, 16 pages, 11 figures
