PAC在DESI中的应用。II. 探索$10^{6}{\rm M}_{\odot}$前沿的星系-暗物质晕连接
PAC in DESI. II. Galaxy-halo connection into the $10^{6}{\rm M}_{\odot}$ frontier
AI总结：
通过DESI Y1 BGS和DECaLS数据，结合SHMR子晕丰度匹配框架，研究了低质量星系形成，发现小暗物质晕中恒星形成效率上升，且通过模型扩展验证了这一特征的稳定性。
摘要：
理解矮星系形成对于检验暗物质模型和再电离物理至关重要。然而，构建低质量恒星质量完整的光谱样本日益困难，潜在的局部空洞进一步复杂了在平均环境中的研究。Photometric object Around Cosmic webs (PAC)方法结合深光电和光谱数据来测量光电对象围绕光谱追踪者的过剩表面密度$\bar{n}_2w_{\rm{p}}(r_{\rm{p}})$，提供了一条可行的途径。我们利用DESI Y1 BGS和DECaLS的349个$\bar{n}_2w_{\rm{p}}(r_{\rm{p}})$测量值，达到$M_*=10^{6.4}\,{\rm M}_{\odot}$，使用基于恒星质量-暗物质质量关系（SHMR）的子晕丰度匹配框架，应用于两个高分辨率$N$-body模拟。所得SHMR被约束到$M_{\rm h}\simeq10^{8.0}\,h^{-1}{\rm M}_{\odot}$，揭示了在$\sim10^{10.0}\,h^{-1}{\rm M}_{\odot}$向更低质量的明显上升，表明小暗物质晕中的恒星形成效率（SFE）上升。这一特征在允许质量依赖性散射、再电离诱导的暗物质占据分数抑制、星系组装偏差和替代宇宙学模型的模型扩展下仍持续存在。结合论文I的发现，我们发现中心红星系主导低质量领域。我们的结果提出一个假设，即在再电离之前，SFE显著高于之前认为的水平，使相对较大的星系在小暗物质晕中形成。这些系统随后被紫外背景淬灭，产生观察到的中心红矮星系。最后，我们得到$3σ$和$5σ$的上质量限制为$10^{8.38}\,h^{-1}{\rm M}_{\odot}$和$10^{8.71}\,h^{-1}{\rm M}_{\odot}$，这是数据所要求的最小暗物质晕的质量限制。
英文摘要：
Understanding dwarf galaxy formation is crucial for testing dark matter models and reionization physics. However, constructing stellar-mass complete spectroscopic samples at low masses is increasingly difficult, and the potential existence of a local void complicates studies in an average environment. The Photometric object Around Cosmic webs (PAC) method, which combines deep photometric and spectroscopic data to measure the excess surface density $\bar{n}_2w_{\rm{p}}(r_{\rm{p}})$ of photometric objects around spectroscopic tracers, offers a promising path forward. We model 349 $\bar{n}_2w_{\rm{p}}(r_{\rm{p}})$ measurements from DESI Y1 BGS and DECaLS, reaching $M_*=10^{6.4}\,{\rm M}_{\odot}$, using a stellar mass-halo mass relation (SHMR)-based subhalo abundance matching framework applied to two high-resolution $N$-body simulations from the Jiutian suite. The resulting SHMR is constrained down to $M_{\rm h}\simeq10^{8.0}\,h^{-1}{\rm M}_{\odot}$, revealing a clear upturn at $\sim10^{10.0}\,h^{-1}{\rm M}_{\odot}$ toward lower masses, indicating rising star-formation efficiency (SFE) in small haloes. This feature persists under extensions of the model that allow mass-dependent scatter, reionization-induced suppression of the halo occupation fraction, galaxy assembly bias, and alternative cosmologies. Combining with the results from Paper I, we find that central red galaxies dominate the low-mass regime. Our results motivate a hypothesis in which SFE is significantly higher than previously thought prior to reionization, enabling relatively massive galaxies to form in small haloes. These systems are subsequently quenched by the UV background, producing the central red dwarf galaxies observed. Finally, we obtain $3σ$ and $5σ$ upper mass bounds of $10^{8.80}\,h^{-1}{\rm M}_{\odot}$ and $10^{10.24}\,h^{-1}{\rm M}_{\odot}$ on the smallest haloes required to exist.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
