AGC 322753：由ALFALFA和FASHI探测到的一个暗星系候选体
AGC 322753: a Dark Galaxy Candidate detected by ALFALFA and FASHI
浏览论文内容
中文总结 AI 辅助
通过ALFALFA和FASHI巡天交叉匹配，探测到暗星系候选体AGC 322753，其HI质量与恒星质量比极高，可能并非完全黑暗，而存在低于光学探测极限的发光对应体。
中文摘要 AI 辅助
我们报告了通过将阿雷西博遗产快速ALFA（ALFALFA）和FAST全天HI（FASHI）巡天的交叉匹配，可能探测到一个暗星系候选体（DGC；AGC 322753）。两个巡天均在相同的退行速度下探测到该源，其HI质量相当，为$2\times10^{9}$ M$_\odot$，且HI谱特征相似。ALFALFA和FASHI的谱均显示出双峰轮廓，这与盘状有序旋转相符，其50%峰值处的HI线宽（$W_{50}$）约为85 km s$^{-1}$。两个波束的共同交集使得源的位置得以被约束，其精度远高于任一单独巡天。由于被两台射电望远镜探测到，排除了射频干扰（RFI）的可能性。在DESI遗产成像巡天中，未发现暗于约27.5 mag arcsec$^{-2}$的光学对应体，由此得出恒星质量上限为$M_\star \lesssim 5\times10^{7}$ M$_\odot$。鉴于该恒星质量上限，AGC 322753的$M_{\rm HI}/M_\star \gtrsim 40$。其HI质量高于完全无恒星暗晕的预期值；这可能意味着AGC 322753并非完全“暗”，而可能拥有一个低于当前光学探测极限的发光对应体。
英文摘要
We report the possible detection of a Dark Galaxy Candidate (DGC; AGC 322753), via the cross-matching of the Arecibo Legacy Fast ALFA (ALFALFA) and the FAST All Sky HI (FASHI) HI blind surveys. It is detected by both surveys at the same recessional velocity, with a comparable HI mass of $2\times10^{9}$ M$_\odot$, and with similar HI spectral features. The ALFALFA and FASHI spectra show a double-peaked profile, compatible with a disc-like ordered rotation, and an HI linewidth at 50 per cent of the peak ($W_{50}$) of $\sim$85 km s$^{-1}$. The common intersection of the two beams allows the source position to be constrained with much greater precision than in either survey individually. Being detected by both radio telescopes, a Radio Frequency Interference (RFI) origin is excluded. No evidence of an optical counterpart was found down to $\sim$27.5 mag arcsec$^{-2}$ in the DESI Legacy Imaging Surveys, which leads to a stellar mass limit of $M_\star \lesssim 5\times10^{7}$ M$_\odot$. Given this stellar mass limit, AGC 322753 has $M_{\rm HI}/M_\star \gtrsim 40$. The HI mass is higher than expected for totally starless haloes; this could imply that AGC 322753 is not completely 'dark' but could host a luminous counterpart below the current optical detection limit.
发表机构
- Swinburne University of Technology（斯威本科技大学）
机构由 AI 辅助整理，请以论文原文为准。
