The outer Galaxy is an environment with metallicity lower than the Solar one. Because of this, the formation and survival of molecules in star-forming regions located in the inner and outer Galaxy is expected to be different. To gain understanding on how chemistry changes throughout the Milky Way, it is crucial to observe outer Galaxy star-forming regions to constrain models adapted for lower metallicity environments. In this paper we present a new observational project: chemical complexity in star-forming regions of the outer Galaxy (CHEMOUT). The goal is to unveil the chemical composition in 35 dense molecular clouds associated with star-forming regions of the outer Galaxy through observations obtained with the IRAM 30m telescope. In this first paper, we present the sample, and report the detection at 3~mm of simple organic species HCO+, H13CO+, HCN, c-C3H2, HCO, C4H, and HCS+, of the complex hydrocarbon CH3CCH, and of SiO, CCS and SO. From c-C3H2, we estimate new kinematic heliocentric and Galactocentric distances based on an updated rotation curve of the Galaxy. The detection of the molecular tracers does not seem to have a clear dependence on the Galactocentric distance. We also analyse the HCO+ line profiles. We find high velocity wings in ~71% of the targets, and their occurrence does not depend on the Galactocentric distance. Our results, confirmed by a statistical analysis, show that the presence of organic molecules and tracers of protostellar activity is ubiquitous in the low-metallicity environment of the outer Galaxy. Based on this, and on the additional evidence that small, terrestrial planets are omnipresent in the Galaxy, we support previous claims that the definition of Galactic Habitable Zone should be rediscussed in view of the ubiquitous capacity of the interstellar medium to form organic molecules.
One-dimensional and time-dependent modelling of complex organic molecules in protostars
Leiden University（莱顿大学）；University of Bonn（波恩大学）；University College London（伦敦大学学院）；SURF；Leiden Institute of Chemistry, Leiden University（莱顿大学化学研究所）；Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, CNRS, CNES（图卢兹大学、法国国家科学研究中心、法国国家空间研究中心天体物理学与行星学研究所在）；Laboratoire d’astrophysique de Bordeaux, Univ. Bordeaux, CNRS（波尔多大学、法国国家科学研究中心波尔多天体物理实验室）；Korea Astronomy and Space Science Institute（韩国天文学与空间科学研究院）；Korea University of Science and Technology（韩国科学技术院）
PRODIGE - envelope to disk with NOEMA: VII. (Complex) organic molecules in the NGC1333 IRAS4B1 outflow: A new laboratory for shock chemistry
Max-Planck-Institut für extraterrestrische Physik（马克斯·普朗克地外物理学研究所）；University of Rochester（罗切斯特大学）；Max-Planck-Institut für Astronomie（马克斯·普朗克天文学研究所）；Taiwan Astronomical Research Alliance (TARA)（台湾天文研究联盟）；Institute of Astronomy and Astrophysics, Academia Sinica（中央研究院天文及天文物理研究所）
The evolution of C4H and c-C3H2 in molecular cores
Guangxi University（广西大学）；Anhui Normal University（安徽师范大学）；Zhejiang Laboratory（浙江实验室）；Xi’an Jiaotong-Liverpool University（西交利物浦大学）；Shanghai Astronomical Observatory, Chinese Academy of Sciences（中国科学院上海天文台）；Shanghai Jiao Tong University（上海交通大学）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；Korea Astronomy and Space Science Institute（韩国天文学与空间科学研究所）
The SOMA MM Survey. I. An Astrochemical Census of Massive Protostars
INAF, Osservatorio Astrofisico di Arcetri（意大利国家天体物理研究所，阿切特里天文台）；Chalmers University of Technology（查尔姆斯理工大学）；University of Oslo（奥斯陆大学）；University of Virginia（弗吉尼亚大学）；Kent State University（肯特州立大学）；Shanghai Jiao Tong University（上海交通大学）；National Astronomical Observatory of Japan, National Institutes of Natural Sciences（日本国立天文台，国立自然科学研究院）；Instituto de Astrofísica de Andalucía, CSIC（安达卢西亚天体物理学研究所，西班牙高等科学理事会）；California Institute of Technology（加州理工学院）；European Southern Observatory（欧洲南方天文台）
Origins of complex organic molecules in L1551 IRS 5: Interplay of thermal heating and accretion shocks
Korea Astronomy and Space Science Institute（韩国天文与空间科学研究院）；Department of Physics and Astronomy, Seoul National University（首尔大学物理与天文学系）；Department of Physics and Astronomy, Graduate School of Science and Engineering, Kagoshima University（鹿儿岛大学理工学研究科物理与天文学系）；Academia Sinica Institute of Astronomy & Astrophysics（中央研究院天文及天文物理研究所）
The ALMA-ATOMS survey: Methanol emission in a large sample of hot molecular cores
Yunnan University（云南大学）；Shanghai Astronomical Observatory, Chinese Academy of Sciences（中国科学院上海天文台）；Kunming University of Science and Technology（昆明理工大学）；Max Planck Institute for Astronomy（马克斯·普朗克天文学研究所）；Peking University（北京大学）
