We have entered an era where the gas mass estimates of distant galaxies do not rely on a single tracer but rather on an inventory of different and independent methods, much like the case for the determination of the star formation rate (SFR) of the galaxies. This is crucial as the traditional Mgas tracers, i.e. low-J CO transition lines and dust continuum emission are becoming highly uncertain as we move to higher redshifts due to metallicity and CMB effects. Here, we present a homogeneous and statistically significant investigation of the use of atomic carbon as an alternative Mgas tracer (Valentino et al.2018) and provide evidence of optically thick far-IR emission in high−z starbursts that point towards higher dust temperatures and lower dust and gas mass estimates than previously inferred (Cortzen et al.2019, submitted). Finally, we present direct observations of the effect of the CMB on the far-IR SEDs of high-z SBs, manifested by unphyscally large (β = 2.5–3.5) apparent spectral indexes in R-J tail (Jin et al. 2019, submitted).

It has long been suspected that winds of thermal and/or relativistic particles are a common feature of both active and normal galaxies. Galactic winds are likely to be an important mechanism, particularly at high redshift, by which energy and metals from galaxies are subsequently dumped into the intergalactic medium. Both observational and theoretical studies of wind processes remain in their infancy, largely because astrophysical winds are difficult to detect. Future satellite missions will make systematic surveys possible for the first time. In this review, we summarise the current evidence for galactic-scale winds, particularly in energy bands where the wind emission is spatially resolved. We also discuss observational limitations and problems of interpretation.

Accretion of gas from the cosmic web to galaxy halos and ultimately their disks is a prediction of modern cosmological models but is rarely observed directly or at the full rate expected from star formation. Here we illustrate possible large-scale cosmic HI accretion onto the nearby dwarf starburst galaxy IC10, observed with the VLA and GBT. We also suggest that cosmic accretion is the origin of sharp metallicity drops in the starburst regions of other dwarf galaxies, as observed with the 10-m GTC. Finally, we question the importance of cosmic accretion in normal dwarf irregulars, for which a recent study of their far-outer regions sees no need for, or evidence of, continuing gas buildup.

We present GALEV evolutionary synthesis models for Simple Stellar Populations (SSPs = single burst, single metallicity) like star clusters or galaxy pixels and for galaxies of various types on the basis of their respective typical star formation histories, ranging from exponentially declining on a timescale of 1Gyr for the classical elliptical model through constant for Sd galaxies, and also allowing for starbursts of various strengths occurring at various evolutionary stages. Models yield the time evolution of the stellar population in terms of color-magnitude diagrams CMDs ($U$\dots $K$), spectra (90Å…160$\mu$m) including gaseous emission in terms of lines and continuum, luminosities, colors and M/L-ratios in various filter systems (e.g. Johnson $U$\dots $K$, HST, Washington, Strömgren), and Lick indices (http://www.astro.physik.uni-goettingen.de/~galev). For galaxies, the redshift evolution is obtained from the time-evolving spectra assuming a standard cosmology (H$_0=65, \Omega_0=0.3, \Omega_{\Lambda}=0.7$) and consistently accounting for evolutionary and cosmological corrections as well as for the attenuation of light from distant galaxies by intervening HI.

We present here starburst models based on the most recent grids of stellar evolutionary tracks obtained by the Geneva group. These new models, computed with enhanced mass loss rates during the main sequence and the Wolf-Rayet WNL phases, very well reproduce the luminosities, surface abundances and statistics of WR stars (Maeder & Meynet 1994). This change of the mass loss rates considerably affects the way the WR stars, born in a starburst's episode, are distributed among the different WR subtypes. We compare the theoretical predictions with recent observations and conclude that: (1) to reproduce the high observed ratios of WNL to O-type stars, a flat IMF seems to be required; and (2) the models which reproduce the best the observed characteristics of WR stars, i.e., those computed with an enhanced mass loss rate, can also account for the observed properties of the WR populations observed in starbursts. Moreover, the possible presence of numerous WC stars found in the low metallicity He2-10 A starburst by Vacca and Conti (1992), can only be accounted for when the high mass loss rate stellar models are used.