Why the Northern Hemisphere Needs a 30-40 m Telescope and the Science at Stake: Cosmology and High-z Universe

TL;DR

A 30-40 meter-class telescope in the Northern Hemisphere is crucial for advancing cosmology and understanding the early universe, complementing space observatories and enabling rapid, diverse, and statistically powerful observations.

Contribution

The paper advocates for establishing a Northern Hemisphere extremely large telescope to enhance observational capabilities and address key questions in cosmology and high-redshift universe studies.

Findings

Northern ELT/TMT will improve sky coverage and observational diversity.

It will enable rapid response to transient and high-energy events.

The facility will complement space telescopes like JWST and Euclid.

Abstract

Full sky coverage with 30-40 meter-class telescopes is essential to answer fundamental questions in Astrophysics, Cosmology, and Physics, such as the composition of the Universe and the formation of the first stars and supermassive black holes. An ELT/TMT-like telescope in the Northern Hemisphere is a fundamental and necessary facility to provide multiplexing of observing power, diversity of instrumentation, rapid response, and statistical power required to address the questions and the problems, current and future, unveiled by full sky observatories such as JWST, Euclid, or Roman space telescopes. The Northern ELT/TMT will expedite the study of unique, extreme, rare, transient, and/or high-energy events which will give the most information about fundamental Physics problems in the era of multi-messenger and time-domain Astronomy.