# ISM conditions in z~0.2 Lyman-Break Analogs

## TL;DR

This study analyzes the interstellar medium conditions in z~0.2 Lyman-Break Analogs using FIR and CO observations, revealing extreme ISM properties similar to high-redshift main sequence galaxies, aiding future observational planning.

## Contribution

It provides the first detailed ISM property analysis of LBAs at z~0.2, comparing them to high-redshift and local galaxies, and highlights their similarity to high-redshift MS galaxies.

## Key findings

- LBAs have extreme ISM conditions with low temperature and high density.
- LBAs show no [CII] deficit despite high sSFRs.
- Their ISM resembles high-redshift MS galaxies more than local starbursts.

## Abstract

We present an analysis of far--infrared (FIR) [CII] and [OI] fine structure line and continuum observations obtained with $Herschel$/PACS, and CO(1-0) observations obtained with the IRAM Plateau de Bure Interferometer, of Lyman Break Analogs (LBAs) at $z\sim 0.2$. The principal aim of this work is to determine the typical ISM properties of $z\sim 1-2$ Main Sequence (MS) galaxies, with stellar masses between $10^{9.5}$ and $10^{11}$ $M_{\odot}$, which are currently not easily detectable in all these lines even with ALMA and NOEMA. We perform PDR modeling and apply different IR diagnostics to derive the main physical parameters of the FIR emitting gas and dust and we compare the derived ISM properties to those of galaxies on and above the MS at different redshifts. We find that the ISM properties of LBAs are quite extreme (low gas temperature, high density and thermal pressure) with respect to those found in local normal spirals and more active local galaxies. LBAs have no [CII] deficit despite having the high specific star formation rates (sSFRs) typical of starbursts. Although LBAs lie above the local MS, we show that their ISM properties are more similar to those of high-redshift MS galaxies than of local galaxies above the main sequence. This data set represents an important reference for planning future ALMA [CII] observations of relatively low-mass MS galaxies at the epoch of the peak of the cosmic star formation.