The Future of IMF studies with the ELT and MICADO I: The local Universe as a resolved IMF laboratory

TL;DR

This study evaluates MICADO at the ELT's capability to detect low-mass stars in dense stellar regions across various distances, enabling detailed IMF studies in the local Universe.

Contribution

It provides the first detailed estimates of MICADO's sensitivity to low-mass stars in dense clusters at different distances, considering instrumental effects.

Findings

MICADO can resolve stellar densities below 10^3 stars arcsec^-2.

Lowest detectable stellar mass in the LMC is about 0.1 Msun.

High-mass stars (>2 Msun) can be studied in galaxies up to 2 Mpc away.

Abstract

Aims. In this work we aim to estimate the lowest stellar mass that MICADO at the ELT will be able to reliably detect given a stellar density and distance. We also show that instrumental effects that will play a critical role, and report the number of young clusters that will be accessible for IMF studies in the local Universe with the ELT. Methods. We used SimCADO, the instrument simulator package for the MICADO camera, to generate observations of 56 dense stellar regions with densities similar to the cores of young stellar clusters. We placed the cluster fields at distances between 8 kpc and 5 Mpc from the Earth, implying core densities from 10^2 to 10^5 stars arcsec^-2, and determined the lowest reliably observable mass for each stellar field through point-spread function (PSF) fitting photometry. Results. Our results show that stellar densities of <10^3 stars arcsec^-2 will be easily resolvable by MICADO. The lowest reliably observable mass in the Large Magellanic Cloud will be around 0.1 Msun for clusters with densities <10^3 stars arcsec^-2. MICADO will be able to access the stellar content of the cores of all dense young stellar clusters in the Magellanic Clouds, allowing the peak and shape of the IMF to be studied in great detail outside the Milky Way. At a distance of 2 Mpc, all stars with M > 2 Msun will be resolved in fields of <10^4 stars arcsec^-2 , allowing the high-mass end of the IMF to be studied in all galaxies out to and including NGC300.