We obtained follow-up HST observations of the seven low surface brightness galaxies discovered with the Dragonfly Telephoto Array in the field of the massive spiral galaxy M101. Out of the seven galaxies, only three were resolved into stars and are potentially associated with the M101 group at $D=7\text{ Mpc}$. Based on HST ACS photometry in the broad F606W and F814W filters, we use a maximum likelihood algorithm to locate the Tip of the Red Giant Branch (TRGB) in galaxy color-magnitude diagrams. Distances are $6.38^{+0.35}_{-0.35}, 6.87^{+0.21}_{-0.30}$ and $6.52^{+0.25}_{-0.27} \text{ Mpc}$ and we confirm that they are members of the M101 group. Combining the three confirmed low luminosity satellites with previous results for brighter group members, we find the M101 galaxy group to be a sparsely populated galaxy group consisting of seven group members, down to $M_V = -9.2 \text{ mag}$. We compare the M101 cumulative luminosity function to that of the Milky Way and M31. We find that they are remarkably similar; In fact, the cumulative luminosity function of the M101 group gets even flatter for fainter magnitudes, and we show that the M101 group might exhibit the two known small-scale flaws in the $Λ\textrm{CDM}$ model, namely `the missing satellite' problem and the `too big to fail' problem. Kinematic measurements of M101$'$s satellite galaxies are required to determine whether the `too big to fail' problem does in fact exist in the M101 group.
The Dragonfly Wide Field Survey. II. Accurate Total Luminosities and Colors of Nearby Massive Galaxies and Implications for the Galaxy Stellar Mass Function
大质量星系的恒星质量估计容易受到测光系统误差的影响，这是由于它们的扩展光剖面。在这项研究中，我们使用的数据从蜻蜓广域巡天（DWFS），以准确地测量总光度和附近的大质量星系的颜色。调查的低表面亮度限制（$μ_g \approx $ 31 mag arcsec $^{-2}$ on a one arcmin scale）允许我们实施一种基于整合1-D表面亮度轮廓的方法，该方法最小程度地依赖于任何参数化。我们在GAMA巡天的基础上，用$\log M_*/M_\odot > 10.75$构造了1188个大质量星系的样本，测量了它们的总光度和$g-r$颜色。然后，我们将我们的测量结果与斯隆数字巡天（SDSS）成像的各种既定方法进行比较，重点关注GAMA调查所青睐的方法。在一般情况下，我们发现，星系是明亮的$r$带的平均${\sim}0.05$等和蓝色的$g-r$颜色的$\sim 0.06$等相比，GAMA测量。这两个差异对恒星质量的估计有相反的影响。$5\%$的总光度较大，但质光比较$\sim 10\%$低。综合效应是，大质量星系的恒星质量估计减少了$7\%$。反过来，这意味着大质量星系的数量密度发生了微小的变化：$\leq 30\%$在$\log M_*/M_\odot \geq 11$。
ALMA FACTS III. High-Resolution CO(2-1)/CO(1-0) Maps of Twelve Nearby Galaxies
Stony Brook University（石溪大学）；Institute of Astronomy, Graduate School of Science, The University of Tokyo（东京大学理学研究科天文学研究所）；National Astronomical Observatory of Japan（日本国立天文台）；Joint ALMA Observatory（ALMA联合观测站）；Division of Liberal Arts, Kogakuin University（工学院大学教养学部）；Research Center for Physics and Mathematics, Osaka Electro-Communication University（大阪电通大学理数研究中心）
Quantifying Feedback from Narrow Line Region Outflows in Nearby Active Galaxies. III. Results for the Seyfert 2 Galaxies Markarian 3, Markarian 78, and NGC 1068
Active Galactic Nuclei and STaR fOrmation in Nearby Galaxies AGNSTRONG. III. A Study on Ionized and Warm Molecular Gas Outflows of 6 Type-2 AGNs
Department of Astronomy, University of Science and Technology of China（中国科学技术大学天文系）；School of Astronomy and Space Science, University of Science and Technology of China（中国科学技术大学天文与空间科学学院）
CO Multi-line Imaging of Nearby Galaxies (COMING). III. Dynamical effect on molecular gas density and star formation in the barred spiral galaxy NGC 4303
作为近星系CO多线成像（COMING）计划的一部分，我们给出了对邻近棒旋星系NGC 4303的$^{12}$ CO（$J$ = 1 - 0）和$^{13}$ CO（$J$ =1-0）同步映射的结果.棒旋星系在棒区的恒星形成效率（SFE）通常比旋臂低。本文利用CO数据结合档案远紫外和24 $μ$ m数据研究了银盘内8个不同区域分子气体$n(\rm{H}_2)$的SFE和体积密度之间的关系。我们证实，在酒吧区的SFE是低于39%，在旋臂。此外，在各个区域的光谱进行速度对齐堆叠分析。作为叠加的结果，$^{12}$ CO与$^{13}$ CO的积分强度比（$R_{12/13}$）范围为10至17。通过对$R_{12/13}$的非局域热力学平衡（non-LTE）分析，确定了分子气体的动力学温度，导出了$n(\rm{H}_2)$.横杠内$n(\rm{H}_2)$密度比臂内低31-37%，SFE与$n(\rm{H}_2)$之间有较强的正相关，相关系数为$\sim 0.8$。此外，我们还发现了$n(\rm{H}_2)$对分子间云速度色散（$ΔV/ \sin i$）的依赖性。具体地，当$ΔV/ \sin i < 100$ km是$^{-1}$时，$n(\rm{H}_2)$随着$ΔV/ \sin i$的增加而增加。另一方面，当$ΔV/ \sin i > 100$ km s $^{-1}$时，$n(\r…
The GMRT archive atomic gas survey -- III. Comparative Study of Dark Matter Halos in Nearby Galaxies
Indian Institute of Science（印度科学研究所）；Indian Institute of Astrophysics（印度天体物理研究所）；Max-Planck-Institut für Radioastronomie (MPIfR)（马克斯·普朗克射电天文研究所）；Institute of Astronomy and National Astronomical Observatory, Bulgarian Academy of Sciences（保加利亚科学院天文学与国家天文台）；New Mexico Institute of Mining and Technology（新墨西哥矿业理工学院）；Indian Institute of Technology Indore（印度印多尔理工学院）；ASTRON – Netherlands Institute for Radio Astronomy（荷兰射电天文研究所）；National Centre for Radio Astrophysics (NCRA–TIFR)（国家射电天体物理学中心）
Spectrally and spatially resolved (sub)millimeter HCN-to-HCO$^{+}$ flux ratios in nearby ultraluminous infrared galaxies
National Astronomical Observatory of Japan, National Institutes of Natural Sciences (NINS)（日本国立天文台，国立自然科学研究院）；Department of Astronomy, School of Science, Graduate University for Advanced Studies (SOKENDAI)（高级研究大学院大学（SOKENDAI）理学部天文学科）；Toyo University（东洋大学）；Institute of Pure and Applied Sciences, University of Tsukuba（筑波大学纯应用科学研究所）；Tomonaga Center for the History of the Universe, University of Tsukuba（筑波大学丰顺伽宇宙历史中心）；Tsukuba Institute for Advanced Research (TIAR), University of Tsukuba（筑波大学筑波高等研究院 (TIAR)）；Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency（日本宇宙航空研究开发机构宇宙科学研究所）
TRAO Survey of Nearby Filamentary Molecular clouds, the Universal Nursery of Stars (TRAO-FUNS). III. Filaments and dense cores in the NGC 2068 and NGC 2071 regions of Orion B
Tracing the Origin of Moving Groups. III. Detecting Moving Groups in The LAMOST DR7
我们重新审视移动集团（MG）在太阳附近的样本91969附近的恒星从LAMOST DR 7。利用小波技术和蒙特卡罗模拟，在$V-\sqrt{U^2+2V^2}$空间同时探测到了5个MG和一个新的候选者，它们位于$V \simeq$-130 km s $^{-1}$.考虑到其他已知的MG，我们的结论是，在银河系盘MG的间距约为15 $\sim$ 25公里秒$^{-1}$沿$V$速度。通过[Fe/H] $-$ [Mg/Fe]分布和年龄分析了所检测到的MG的来源。我们的研究结果支持归因于连续共振机制的起源可能是由银河系的酒吧或旋臂。
Direct Evidence for Outflow Driven by Wolf-Rayet Stars in the Nearby Galaxy PGC44685
Nanjing University（南京大学）；National Astronomical Observatory of Japan（日本国立天文台）；Nanjing Normal University（南京师范大学）；Anqing Normal University（安庆师范大学）；QingHai Univ（青海大学）
Diversity of Ionized Gas Structures in Nearby Metal-poor Dwarf Galaxies
University of Tsukuba（筑波大学）；Tsukuba Institute for Advanced Research (TIAR), University of Tsukuba（筑波大学先进研究院）；Tomonaga Center for the History of the Universe (TCHoU), Faculty of Pure and Applied Sciences, University of Tsukuba（筑波大学理学院朝永振一郎宇宙历史中心）；The University of Tokyo（东京大学）；Stockholm University（斯德哥尔摩大学）；Universidad Nacional Autónoma de México, Instituto de Astronomía（墨西哥国立自治大学天文学研究所）；Nagoya University（名古屋大学）；Waseda University（早稻田大学）
Investigating the Young Stellar Populations and Hierarchies in Nearby Galaxies with the UVIT. III. Evidence for a Largest Scale of Correlated Stellar Structures and a Non-universal Fractal Dimension
Indian Institute of Astrophysics（印度天体物理研究所）；Pondicherry University（本地治里大学）；Leibniz-Institut für Astrophysik Potsdam（波茨坦莱布尼茨天体物理研究所）；Center for Computational Astrophysics, Flatiron Institute（平顿研究所计算天体物理学中心）；Rutgers University（罗格斯大学）；S. N. Bose National Centre for Basic Sciences（S.N. 玻色基础科学国家中心）；Australian National University（澳大利亚国立大学）；Macquarie University（麦考瑞大学）；IIT (BHU)（印度技术学院（贝拿勒斯印度教大学））
