ELT Spectroscopy of Extragalactic Massive Stars

TL;DR

This paper discusses the potential of the ELT's MOSAIC instrument for spectroscopy of extragalactic massive stars, enabling studies in very distant and metal-poor galaxies, with preliminary simulations showing promising results.

Contribution

It introduces performance simulations for ELT's MOSAIC instrument, demonstrating feasibility of spectroscopy of massive stars up to 4 Mpc away.

Findings

Sufficient signal-to-noise can be achieved in one night for galaxies 3-4 Mpc away.

Ultraviolet spectroscopy beyond 1 Mpc requires future space telescopes like LUVOIR.

Simulations support the scientific potential of ELT for extragalactic massive star studies.

Abstract

Quantitative spectroscopy of O-type stars in galaxies beyond 1 Mpc requires the unprecedented sensitivity of the so-called Extremely Large Telescopes. Visible spectroscopy with these exciting new facilities will give us the first chance to explore the properties of large samples of massive stars in very metal-poor galaxies, as well as the broad range of environments in the galaxies of the Sculptor Group and beyond. In this context, we introduce performance simulations of visible spectroscopy of extragalactic massive stars with the MOSAIC instrument, which is a multi-object spectrograph in development for the European Extremely Large Telescope (ELT). Preliminary results demonstrate that we can obtain sufficient signal-to-noise from one night of observations in galaxies out to distances of 3 to 4 Mpc (V = 22-23 mag). We also highlight the goal of obtaining ultraviolet spectroscopy of the same individual stars beyond 1 Mpc; this will require a future large-aperture space telescope with UV capabilities such as the LUVOIR concept currently under study.