doi.eso.org

• Krogager, Jens-Kristian [CRAL, University Claude Bernard Lyon 1, ENS of Lyon, France]
• Leighly, Karen M. [Homer L. Dodge Department of Physics and Astronomy, The University of Oklahoma, USA]
• Fynbo, Johan Peter Uldall [Niels Bohr Institute, University of Copenhagen, Denmark; The Cosmic DAWN Center, Denmark]
• Heintz, Kasper Elm [Niels Bohr Institute, University of Copenhagen, Denmark; The Cosmic DAWN Center, Denmark]
• Balashev, Sergei [Ioffe Institute, Saint Petersburg, Russia]
• Bauer, Franz Erik [Millennium Institute of Astrophysics, Santiago, Chile; Institute of Astrophysics and Centre for Astroengineering, Faculty of Physics, Pontifical Catholic University of Chile, Santiago, Chile]
• Berg, Trystyn [Ioffe Institute, Saint Petersburg, Russia; Department of Astronomy, University of Chile, Santiago, Chile]
• Choi, Hyunseop [Department of Physics, University of Montreal, Canada]
• Christensen, Lise Bech [Niels Bohr Institute, University of Copenhagen, Denmark; The Cosmic DAWN Center, Denmark]
• De Cia, Annalisa [ESO; Department of Astronomy, University of Geneva, Switzerland]
• Ellison, Sara [Department of Physics & Astronomy, University of Victoria, Canada]
• Geier, Stefan [Canary Islands Institute of Astrophysics, Tenerife, Spain; Gran Telescopio Canarias, La Palma, Spain]
• Glikman, Eilat [Department of Physics, Middlebury College, USA]
• Gupta, Neeraj [Inter-University Centre for Astronomy and Astrophysics, Pune, India]
• Konstantopoulou, Christina [Department of Astronomy, University of Geneva, Switzerland]
• Kosenko, Daria [Ioffe Institute, Saint Petersburg, Russia]
• Ledoux, Cédric [European Southern Observatory (ESO)]
• López, Sebastian [Department of Astronomy, University of Chile, Santiago, Chile]
• Milvang-Jensen, Bo [Niels Bohr Institute, University of Copenhagen, Denmark; The Cosmic DAWN Center, Denmark]
• Morabito, Leah [Centre for Extragalactic Astronomy, Department of Physics, Durham University, UK; Institute for Computational Cosmology, Department of Physics, Durham University, UK]
• Møller, Palle [ESO; Niels Bohr Institute, University of Copenhagen, Denmark]
• Noterdaeme, Pasquier [Paris Institute of Astrophysics, France; French-Chilean Laboratory for Astronomy, Santiago, Chile]
• Pettini, Max [Institute of Astronomy, University of Cambridge, UK]
• Prochaska, Jason Xavier [Department of Astronomy & Astrophysics, UCO/Lick Observatory, University of California, USA; Kavli Institute for the Physics and Mathematics of the Universe, Kashiwa, Japan]
• Raimundo, Sandra [Department of Physics and Astronomy, University of California, Los Angeles, USA; Niels Bohr Institute, University of Copenhagen, Denmark; Department of Physics & Astronomy, University of Southampton, UK]
• Richard, Johan [CRAL, University Claude Bernard Lyon 1, ENS of Lyon, France]
• Srianand, Raghunathan [Inter-University Centre for Astronomy and Astrophysics, Pune, India]
• Telikova, Ksenia [European Southern Observatory (ESO); Ioffe Institute, Saint Petersburg, Russia]
• Terndrup, Donald [Department of Astronomy, The Ohio State University, USA]
• Tripp, Todd M. [Department of Astronomy, University of Massachusetts, USA]
• Vestergaard, Marianne [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Denmark; Niels Bohr Institute, University of Copenhagen, Denmark]
• Zafar, Tayyaba [Australian Astronomical Optics, Macquarie University, Australia]

The 4MOST–Gaia Purely Astrometric Quasar Survey (4G-PAQS) will carry out the first large-scale, colour-independent quasar survey selected solely on the basis of astrometry from Gaia. Our main objective is to quantify the selection effects of current colour-selected samples. These colour-selected samples bias our view of the neutral gas and its chemical enrichment because of dust obscuration and reddening of optical colours. Moreover, the broad absorption-line outflows observed in quasars are under-represented by optical colour selection. 4G-PAQS will provide the first sample to overcome these challenges and will constrain the physical and chemical properties of gas in galaxies and quasars at cosmic noon.