4MOST: Project overview and information for the First Call for Proposals

TL;DR

4MOST is a new high-multiplex spectroscopic survey instrument for the VISTA telescope, offering wide-field observations with multiple spectrographs, enabling large-scale astronomical surveys and community proposals.

Contribution

This paper introduces 4MOST's design, capabilities, operational plans, and survey policies, providing essential information for future proposals and scientific use.

Findings

Designed for high-multiplex, wide-field spectroscopy

Supports large-scale community surveys with flexible policies

Enables diverse scientific investigations with planned operational scheme

Abstract

We introduce the 4-metre Multi-Object Spectroscopic Telescope (4MOST), a new high-multiplex, wide-field spectroscopic survey facility under development for the four-metre-class Visible and Infrared Survey Telescope for Astronomy (VISTA) at Paranal. Its key specifications are: a large field of view (FoV) of 4.2 square degrees and a high multiplex capability, with 1624 fibres feeding two low-resolution spectrographs ($R = \lambda/\Delta\lambda \sim 6500$), and 812 fibres transferring light to the high-resolution spectrograph ($R \sim 20\,000$). After a description of the instrument and its expected performance, a short overview is given of its operational scheme and planned 4MOST Consortium science; these aspects are covered in more detail in other articles in this edition of The Messenger. Finally, the processes, schedules, and policies concerning the selection of ESO Community Surveys are presented, commencing with a singular opportunity to submit Letters of Intent for Public Surveys during the first five years of 4MOST operations.