The Andromeda (M31) galaxy subtends nearly 100 sq. deg. on the sky, with severe contamination from the Milky Way halo stars whose surface density displays a steep gradient across the entire M31 field-of-view. Planetary Nebulae (PNe) are a population of stars firmly associated with M31, that are excellent tracers of light, chemistry and motion in galaxies. We present a 16 sq. deg. survey of the disk and inner halo of M31 with MegaCam@CFHT to identify PNe, characterize their luminosity-specific PN number and luminosity function (PNLF). PNe were identified based on their bright OIII 5007 $\unicode{x212B}$ emission and absence of a continuum. Subsamples of the faint PNe were independently confirmed by matching with resolved Hubble Space Telescope sources from the PHAT survey and spectroscopic follow-up observations with HectoSpec@MMT. The current survey reaches 2 mag fainter than the previous most-sensitive survey. We identify 4289 PNe, of which only 1099 were previously known. By comparing the PN number density with the surface brightness profile of M31 out to ~30 kpc along the minor-axis, we find that the stellar population in the inner halo has a 7 times larger luminosity-specific PN number value than that of the disk. It indicates that the stellar population at deprojected minor-axis radii larger than ~10 kpc is different from that in the M31 disk. We measure the PNLF and find a bright cut-off and a slope consistent with the previous determination by Ciardullo et al. (1989). Interestingly, it shows a significant rise at the faint end, present in all radial bins covered by the survey, much steeper than that observed for the Magellanic clouds and Milky Way bulge. M31 shows two major episodes of star formation and the rise in the faint end of the PNLF is possibly associated with the older stellar population. It may also be a result of varying opacity of the PNe.
CFHT MegaCam Two Deep Fields Imaging Survey (2DFIS) I: Overview
Purple Mountain Observatory, Chinese Academy of Sciences（中国科学院紫金山天文台）；Hefei Institute of Technology（合肥工业大学）；University of Science and Technology of China（中国科学技术大学）；CEA Paris-Saclay（巴黎萨克雷原子能委员会）；Kavli Institute for Particle Astrophysics and Cosmology（卡弗里粒子天体物理与宇宙学研究所）；Brown University（布朗大学）；Shanghai Normal University（上海师范大学）；Tsung-Dao Lee Institute and State Key Laboratory of Dark Matter Physics, Shanghai Jiao Tong University（上海交通大学）
Dissecting the Perseus-Pisces supercluster observed with CFHT-MegaCam: Investigating environmental effects on galaxy morphology
CEA（法国原子能和替代能源委员会）；CNRS（法国国家科学研究中心）；AIM（天体物理与分子研究实验室）；Institut d’Astrophysique de Paris（巴黎天体物理学研究所）；Sorbonne Université（索邦大学）；CNES（法国国家空间研究中心）；LAM（拉奥朗天体物理实验室）；INAF - Osservatorio Astronomico di Cagliari（意大利国家天体物理研究所卡利亚里天文台）；Observatoire Astronomique de Strasbourg（斯特拉斯堡天文台）；Université de Strasbourg（斯特拉斯堡大学）
CFHT MegaCam Two Deep Fields Imaging Survey (2DFIS) II: Decoding the Lensing Profile of a "Rotating" Cluster with Deep CFHT Imaging
Shanghai Normal University（上海师范大学）；Shanghai Astronomical Observatory, Chinese Academy of Sciences（中国科学院上海天文台）；China Three Gorges University（三峡大学）；Hefei Institute of Technology（合肥工业大学）；University of Science and Technology of China（中国科学技术大学）；Purple Mountain Observatory, Chinese Academy of Sciences（中国科学院紫金山天文台）；Université Paris-Saclay（巴黎萨克雷大学）；Université Paris Cité（巴黎西岱大学）
本研究通过深度 CFHT 成像分析 RXCJ0110.+=1358 星系团，揭示光学双峰性源于丝状体投影，解决光学与 X 射线观测间的矛盾。
A Megacam Survey of Outer Halo Satellites. IV. Two foreground populations possibly associated with the Monoceros substructure in the direction of NGC2419 and Koposov2
The ultracool-field dwarf luminosity-function and space density from the Canada-France Brown Dwarf Survey
上下文由于最近和正在进行的大规模调查，在过去十年中发现了数百颗褐矮星。加拿大-法国棕矮星巡天（英语：Canada-France Brown Dwarf Survey）是一项利用加拿大-法国-夏威夷望远镜（英语：Canada-France-Hawaii Telescope）上的MegaCam照相机进行的宽视场冷棕矮星巡天。目标。我们的目标是找到超冷的棕矮星，并从一个大的和均匀的L和T矮星样本约束场棕矮星光度函数和质量函数。方法.我们在CFHT/MegaCam i'和z'图像中确定候选者，并在几个望远镜上用指向近红外（NIR）成像跟踪它们。在我们的调查进行到一半时，我们发现了~50个T矮星和~170个L或超冷M矮星，这些矮星是从1400个候选者中抽取的，具有典型的超冷矮星i' - z'颜色，在780平方度内发现。结果我们目前已经完成了对所有候选者的大部分调查的近红外跟踪，从中L矮星到最新的T矮星，已知具有超冷矮星的颜色。这使我们能够利用一个完整的和定义良好的102个超冷矮星的样本来研究场矮星的光度函数和空间密度。结论.我们发现L5到T0晚期矮星的密度为2.0 pm0.8 x 10-3个pc-3，T0.5到T5.5矮星的密度为1.4 pm0.3 x 10-3个pc-3，T6到T8矮星的密度为5.3 pm3.1 x 10-3个pc-3。我们发现，这些结果更符合一个平坦的亚恒星质量函数。在T…
The Pristine survey XXIX. Data Release 2: Photometric metallicities for 15 millions stars down to $G\sim 20.5$
School of Astronomy and Space Science, Nanjing University（南京大学天文与空间科学学院）；Key Laboratory of Modern Astronomy and Astrophysics, Nanjing University, Ministry of Education（南京大学现代天文与天体物理教育部重点实验室）；Institute of Astronomy, University of Cambridge（剑桥大学天文学研究所）；Université de Strasbourg, CNRS, Observatoire astronomique de Strasbourg, UMR 7550（斯特拉斯堡大学、法国国家科学研究中心、斯特拉斯堡天文台）；Max-Planck-Institut für Astronomie（马克斯·普朗克天文学研究所）；Kapteyn Astronomical Institute, University of Groningen（格罗宁根大学卡普坦天文研究所）；LIRA, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CY Cergy Paris Université, CNRS（巴黎天文台 LIRA 实验室、巴黎文理研究大学、索邦大学、巴黎西岱大学、塞吉-蓬图瓦兹大学、法国国家科学研究中心）；Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange（蔚蓝海岸大学、蔚蓝海岸天文台、法国国家科学研究中心、拉格朗日实验室）
