Merian巡天：亚银河系质量星系的明亮卫星统计普查
The Merian Survey: A Statistical Census of Bright Satellites of Sub-Milky Way-Mass Galaxies
- Princeton University（普林斯顿大学）
- Stanford University（斯坦福大学）
- Tel Aviv University（特拉维夫大学）
- Amherst College（阿默斯特学院）
- Rutgers, the State University of New Jersey（新泽西州立罗格斯大学）
- Tsinghua University（清华大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
基于Merian巡天首次数据发布，对357个亚银河系质量主星系进行统计普查，识别出约148个明亮恒星形成卫星，发现卫星丰度随主星系质量增加，与TNG50模拟一致，填补了矮星系与银河系质量之间的观测空白。
AI中文摘要：
卫星星系为星系-暗晕联系提供了敏感的检验，但以往研究主要集中于银河系（MW）质量的主星系或少量邻近矮星系主星系。本文利用Merian巡天首次数据发布，对亚银河系质量主星系周围的明亮、恒星形成卫星星系进行了统计普查。我们的样本包含357个主星系，恒星质量范围为$10^{9.5}<M_{\star,\text{host}}<10^{10.5} \\ \text{M}_\odot$，红移范围为$0.07<z<0.09$，均被选为中心星系。Merian的中带成像能够分离该红移范围内星系的H$\alpha$和[O \textsc{iii}]发射线，从而能够高效选择恒星质量低至$M_{\star,\text{sat}}\gtrsim 10^{7.5} \\,\text{M}_\odot$的恒星形成卫星星系。我们在这些主星系的投影维里半径内识别出471个卫星候选体。在统计扣除前景和背景星系的贡献后，我们发现与主星系样本相关的卫星候选体为$148\pm 7$个。我们发现，约60%的主星系在其维里半径内拥有$N_{\rm sat}< 1$个大质量卫星，约22%拥有$1\leq N_{\rm sat}< 2$个，约10%拥有$2\leq N_{\rm sat}< 3$个，约8%拥有$N_{\rm sat} > 3$个。在亚银河系质量范围内，卫星丰度随主星系恒星质量增加而增加，将观测到的趋势从矮星系扩展到银河系质量星系，并与TNG50模拟的预测大体一致。亚银河系质量主星系周围卫星的径向分布与银河系质量主星系周围的分布相似，且与TNG50模拟大体一致。综合来看，这些结果将我们对卫星种群的实证认识扩展到了此前采样稀疏的矮星系与银河系质量主星系之间的过渡区域。
英文摘要：
Satellite populations provide sensitive tests of the galaxy-halo connection, but studies have largely focused on Milky Way (MW)-mass host galaxies or a small number of nearby dwarf galaxy hosts. Here we present a statistical census of bright, star-forming satellite galaxies around sub-MW-mass hosts using the first data release of the Merian Survey. Our sample consists of 357 hosts with stellar mass $10^{9.5}<M_{\star,\text{host}}<10^{10.5} \ \text{M}_\odot$ at redshifts $0.07<z<0.09$, all selected to be central galaxies. Merian's medium-band imaging isolates H$α$ and [O \textsc{iii}] emission lines for galaxies in this redshift range, enabling efficient selection of star-forming satellites down to $M_{\star,\text{sat}}\gtrsim 10^{7.5} \,\text{M}_\odot$. We identify 471 satellite candidates within the projected virial radii of these hosts. After statistically subtracting the contribution from foreground and background galaxies, we find $148\pm 7$ satellite candidates associated with the host sample. We find that $\mathord{\sim} 60\%$ of hosts have $N_{\rm sat}< 1$ massive satellites within their virial radii, $\mathord{\sim} 22\%$ have $1\leq N_{\rm sat}< 2$, $\mathord{\sim} 10\%$ have $2\leq N_{\rm sat}< 3$, and $\mathord{\sim} 8\%$ have $N_{\rm sat} > 3$. Satellite abundance increases with host stellar mass across the sub-MW regime, extending the observed trend from dwarf to MW-mass galaxies and broadly agreeing with predictions from the TNG50 simulation. The radial distribution of satellites around sub-MW-mass hosts is similar to that around MW-mass hosts and broadly consistent with TNG50. Together, these results extend our empirical view of satellite populations across the previously sparsely sampled transition between dwarf and MW-mass hosts.
