This document discusses the three main lines expected to dominate massive-star research in the 2040s, namely: (1) The role of metallicity in stellar evolution, especially in determining the end products such as gravitational-wave progenitors. (2) The initial mass function from the most massive stars to substellar objects. (3) The role of the environment in the different modes of star formation from compact star clusters to born-this-way associations and from massive clusters to small stellar groups. More specifically, we present the contributions to such science that would be enabled by a 30~m type telescope in the northern hemisphere studying spiral galaxies. Those can be grouped in three: our own Galaxy, the Milky Way; the other two spiral galaxies in the Local Group, M31 and M33; and other galaxies within 25 Mpc, such as M101, M51, and NGC~6946. This work is based on the fact that, as of today, no construction of a 30~m telescope has yet started in the northern hemisphere, so even in the best case scenario of such a hypothetical telescope, its full operation would not start until the late 2030s or early 2040s. It makes no assumptions about its location but supposes an instrumentation development similar to that of ELT.
Using commissioning data from the first year of operation of the Canadian Hydrogen Intensity Mapping Experiment's (CHIME) Pulsar backend system, we conduct a systematic analysis of the Faraday Rotation Measure (RM) of the northern hemisphere pulsars detected by CHIME. We present 55 new RMs as well as obtain improved RM uncertainties for 25 further pulsars. CHIME's low observing frequency and wide bandwidth between 400-800 MHz contribute to the precision of our measurements, whereas the high cadence observation provide extremely high signal-to-noise co-added data. Our results represent a signif…
Why the Northern Hemisphere Needs a 30-40 m Telescope and the Science at Stake: Cosmology and High-z Universe
Centro de Astrobiología (CAB), CSIC-INTA（西班牙天文生物学中心）；Kavli Institute for Cosmology, University of Cambridge（剑桥大学卡弗里宇宙学研究所）；Department of Astronomy, University of Geneva（日内瓦大学天文学系）；INAF - Osservatorio Astronomico di Padova（意大利国家天体物理研究院帕多瓦天文台）；Department of Physics and Astronomy, University of California, Los Angeles（加州大学洛杉矶分校物理与天文学系）；Instituto de Astrofísica de Canarias（加那利群岛天文物理研究所）；UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz（加州大学圣克鲁兹分校UCO/利克天文台天文学与天体物理学系）；Department of Physics, University of the Pacific（太平洋大学物理系）
We present a method for calibrating the flux density scale for images generated by the Amsterdam ASTRON Radio Transient Facility And Analysis Centre (AARTFAAC). AARTFAAC produces a stream of all-sky images at a rate of one second in order to survey the Northern Hemisphere for short duration, low frequency transients, such as the prompt EM counterpart to gravitational wave events, magnetar flares, blazars, and other as of yet unobserved phenomena. Therefore, an independent flux density scaling solution per image is calculated via bootstrapping, comparing the measured apparent brightness of sour…
Why the Northern Hemisphere Needs a 30-40 m Telescope and the Science at Stake: Northern Local Star-forming Dwarf Galaxies. Analogues of the First Galaxies and Probes of the Cosmic Metallicity Scale
Universidad de La Laguna（拉帕尔马大学）；Instituto de Astrofísica de Andalucía, IAA-CSIC（安达卢西亚天体物理研究所，西班牙高等科学研究理事会）；Institute for Astronomy, University of Edinburgh, Royal Observatory（爱丁堡大学天文研究所，皇家天文台）；Instituto de Astronomía, Universidad Nacional Autónoma de México（墨西哥国立自治大学天文研究所）；Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg（海德堡大学天文学中心计算天文研究所）
Why the Northern Hemisphere Needs a 30-40 m Telescope and the Science at Stake: Mapping formation pathways of nuclear star clusters across galaxies
Instituto de Astrofísica de Canarias（加那利天体物理研究所）；Universidad de La Laguna（拉古纳大学）；Universidad de Granada（格拉纳达大学）；Instituto Carlos I de Física Teórica y Computacional（卡洛斯一世理论与计算物理研究所）；Università degli Studi di Padova（帕多瓦大学）；Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences（波兰科学院尼古拉·哥白尼天文学中心）；Universidade Federal do Rio Grande do Sul (UFRGS)（南里奥格兰德联邦大学）；Curtin Institute of Radio Astronomy（柯廷射电天文研究所）；University of Vienna（维也纳大学）
Why the Northern Hemisphere Needs a 30-40 m Telescope and the Science at Stake: A Low Surface Brightness Science Case
Institute of Space Sciences (ICE, CSIC)（空间科学研究所）；Instituto de Astrofísica de Canarias (IAC)（加那利天体物理研究所）；Universidad de La Laguna (ULL)（拉古纳大学）；Centro de Estudios de Física del Cosmos de Aragón (CEFCA)（阿拉贡宇宙物理学研究中心）；European Southern Observatory (ESO)（欧洲南方天文台）；Universidad de Valladolid (UVa)（巴利亚多利德大学）；Instituto de Astrofísica e Ciências do Espaço（天体物理与空间科学研究所）；INAF-Astronomical Observatory of Teramo（意大利国家天体物理研究所泰拉莫天文台）；Instituto de Astrofísica de Andalucía (IAA)（安达卢西亚天体物理研究所）；University of Surrey（萨里大学）；Instituto de Física de Cantabria (IFCA)（坎塔布里亚物理研究所）；University of Padova（帕多瓦大学）；Observatory of Strasbourg（斯特拉斯堡天文台）；University of Viena（维也纳大学）；University of Notthingham（诺丁汉大学）
Why the Northern Hemisphere Needs a 30-40 m Telescope and the Science at Stake: Resolved Stellar Populations Studies in M31 and its Satellites
Instituto de Astrofísica de Canarias (IAC)（加那利天体物理学研究所）；Universidad de La Laguna（拉古纳大学）；Centro de Estudios de Física del Cosmos de Aragón (CEFCA)（阿拉贡宇宙物理研究中心）；Division of Astrophysics, Lund University（隆德大学天体物理学系）；University of Rome, Tor Vergata（罗马第二大学（托尔维加塔大学））；INAF—Osservatorio Astronomico di Roma（意大利国家天体物理研究所罗马天文台）；Instituto de Astronomía CU, Universidad Nacional Autónoma de México（墨西哥国立自治大学天文学研究所）；LIRA, Observatoire de Paris, CNRS（巴黎天文台LIRA实验室，法国国家科学研究中心）；INAF - Astronomical Observatory of Abruzzo（意大利国家天体物理研究所阿布鲁佐天文台）；INFN - University of Pisa（比萨大学意大利国家核物理研究所）；Leibniz-Institut für Astrophysik Potsdam（波茨坦莱布尼茨天体物理研究所）；Jeremiah Horrocks Institute, University of La（拉大学杰里迈亚·霍罗克斯研究所）
Why the Northern Hemisphere Needs a 30-40m Telescope and the Science at Stake: Ultra-Low-Mass Dwarf Galaxies Across the Boreal Cosmic Web
Instituto de Astrofísica de Canarias（加那利群岛天体物理学研究所）；Universidad de La Laguna（拉戈亚大学）；Universidad de Granada（格拉纳达大学）；Universidad Autónoma de Madrid（马德里自治大学）；Universidad de La Serena（拉塞雷纳大学）；Canada-France-Hawaii Telescope（加拿大-法国-夏威夷望远镜）；Planetarium La Enseñanza（La Enseñanza 天文馆）；Instituto de Astrofisica de Andalucía（安达卢西亚天体物理学研究所）；INAF – Astronomical Observatory of Brera（意大利国家天体物理研究所布雷拉天文台）；Leiden Observatory（莱顿天文台）
Why the Northern Hemisphere Needs a 30-40 m Telescope and the Science at Stake. How do Planetary Systems Form?
Centro de Astrobiología (CAB), CSIC-INTA（天文生物学中心）；Instituto de Astrofísica de Canarias（加那利天体物理学研究所）；Universidad de La Laguna（拉古纳大学）；Max-Planck Institute for Astronomy (MPIA)（马克斯·普朗克天文学研究所）；LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université de Paris（巴黎天文台LESIA实验室）；Laboratoire d’astrophysique de Bordeaux, Univ. Bordeaux, CNRS（波尔多大学天体物理学实验室）；Institut universitaire de France (IUF)（法国高等研究院）
Why the Northern Hemisphere Needs a 30-40m Telescope and the Science at Stake: from Interstellar Visitors to Planetary Defence
Instituto de Astrofísica de Canarias - IAC（加那利天体物理研究所）；Departamento de Astrofísica, Universidad de La Laguna（拉帕尔马大学天体物理学系）；Instituto de Ciencias y Tecnologías Espaciales de Asturias - ICTEA, Universidad de Oviedo（阿斯图里亚斯空间科技研究所，奥维耶多大学）；Université Côte d’Azur, Observatoire 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）；LIRA, Observatoire de Paris, CNRS, Université PSL, Université Paris Cité, Sorbonne Université（巴黎天文台，法国国家科学研究中心，巴黎文理研究大学，巴黎西岱大学，索邦大学）；Department of Physics, University of Helsinki（赫尔辛基大学物理系）；Instituto de Astrofísica de Andalucía - CSIC（安达卢西亚天体物理研究所，西班牙高等科学研究委员会）；Universidad Complutense de Madrid（马德里康普顿斯大学）；Aix Marseille University, CNRS, CNES, Laboratoire d’Astrophysique de Marseille（艾克斯-马赛大学，法国国家科学研究中心，法国国家空间研究中心，马赛天体物理实验室）；Dipartimento di Fisica e Astronomia, Università di Padova（帕多瓦大学物理与天文学系）；Institute for Space Astrophysics and Planetology - IAPS-INAF（空间天体物理学和行星学研究所，意大利国家天体物理研究所）；Department of High-Energy Astrophysis, Max-Planck-Institut für Extraterrestrische Physik（马克斯·普朗克地外物理学研究所高能天体物理系）；University of Helsinki（赫尔辛基大学）
Why the Northern Hemisphere Needs a 30-40m Telescope and the Science at Stake: Shaping Galaxies and Their Stars with Stellar Population Gradients, IMF Variations and Environmental Drivers in Cluster Early-Type Galaxies
The CHIME telescope (the Canadian Hydrogen Intensity Mapping Experiment) recently built in Penticton, Canada, is currently being commissioned. Originally designed as a cosmology experiment, it was soon recognized that CHIME has the potential to simultaneously serve as an incredibly useful radio telescope for pulsar science. CHIME operates across a wide bandwidth of 400-800 MHz and will have a collecting area and sensitivity comparable to that of the 100-m class radio telescopes. CHIME has a huge field of view of ~250 square degrees. It will be capable of observing 10 pulsars simultaneously, 24…
