We show in this contribution that detailed studies of chemical abundances in UV-selected, H ii and starburst nucleus galaxies, together with the development of new chemical evolution models, put strong constraints on the evolutionary stage of starburst galaxies in terms of star formation history. Although the samples of high-redshift galaxies are still too small for statistical studies, the preliminary results give insight into the nature and evolution of distant star-forming objects and their link with present-day galaxies.

We present high resolution VLT spectra of the optical identification of the high-redshift galaxy SMM J 14011+0252. We concentrate on the C iv 1550Å region of the spectra and compared the data with a spectral synthesis model generated with starburst99.

Radioactive 26Al, ejected by massive stars through winds and supernova explosions, leads to γ-ray line emission that can serve as a probe of the interstellar environment in and near young star clusters. The ~ 1 Myr decay time of 26Al is long enough to allow transport over significant distances, which can cause substantial angular offsets between γ-ray emission and cluster stars. Details of such offsets are determined by the morphology of the ISM. We discuss observations in Cygnus and Orion, and models based on population synthesis methods.

Core-collapse supernovae (SNe) arise from massive stars, which lose mass in the form of stellar winds throughout their lifetimes. We study herein the evolution of the SNe as they grow in the circumstellar medium formed by mass loss from the progenitor star.

We present new observations of Mrk 1087 that indicate this galaxy is experiencing a strong star formation event due to the interaction with -at least- two nearby galaxies, one of them is a star-forming dwarf. We also discover that some of the surrounding non-stellar objects are tidal dwarfs hosting weak starbursts.

The blue compact H ii galaxy CTS 1026 shows very strong WR emission features (Wλ(4680) = 17 Å and Wλ(5800) = 10 Å). We present high s/n optical spectra of the nucleus of this object, augmented by IUE UV spectra. By analysis of the WR profile shapes, we determine the dominant spectral types and the number of WN and WC stars in the star forming region. The number of O-type stars is determined by comparing the observed UV to optical flux distribution to population synthesis models.

Using CFHT-sis Fabry-Perot interferograms of the Wolf-Rayet ring nebula M1-67, we present an investigation of the statistical properties of fluctuating gas motions using structure functions (SFs) traced by Hα emission-line centroid velocities. We consider the SFs 〈|Δv(r)|p〉 of order p, i.e., the spatially averaged moments of order p of the spatial velocity increments at projected spatial scale r of M1-67's velocity field: we test for (i) SF scaling, 〈|Δv(r)|p〉 ∝ rζ(p), and (ii) nonlinearity of the observed scaling exponents ζ(p)s, as expected for intermittent flows. We find that there is a clear correlation at scales 0.02-0.22 pc between the mean quadratic differences of radial velocities and distance over the surface of M1-67. The first and second order SFs are found to scale as 〈|Δv(r)|〉 ∝ r0.5 and 〈|Δv(r)|2〉 ∝ r0.9 (Grosdidier et al. 2001). The former scaling law strongly suggests that supersonic turbulence is at play in M1-67, on the other hand, the latter scaling law agrees very well with Larson-type laws for velocity turbulence. Additionally, we can discuss the nature of the turbulence in terms of Universal Multifractals (UM), a continuous-scale limit of multiplicative cascades (Schertzer & Lovejoy 1987) and derive the level of intermittency in the nebula.

We have used archival Chandra-acis observations to search for X-ray emission from WR stars in the Magellanic Clouds (MCs), where the low interstellar absorption and known distances make it easy to compare X-ray luminosities with spectral types and binary status of WR stars. We have detected X-ray emission from ~20 WR stars in the MCs with X-ray luminosities of 6.6×1032-1.4×1035 ergs s–1. The analysis of the X-ray spectra of the brightest sources indicates that the X-ray emitting gas has temperatures ≥ 1.0×107 K, as expected in colliding winds. We will compare these results with the binary status of the WR stars to determine the amounts of the X-ray emission produced in the colliding winds for WR stars in binary systems and to assess the X-ray emission from single WR stars.

We present results from a Chandra X-ray observation of the dwarf starburst galaxy NGC 4214, a galaxy containing several young star forming regions. Starburst regions are known to be associated with diffuse X-ray emission, and in this case X-ray emission from the galaxy shows an interesting morphological structure with a bright X-ray ring of emission within the galaxy.

We present a spectrophotometric survey of 111 H ii galaxies. Observations were made at the ESO 1.52m telescope, with the b&c spectrograph. Our sample presents a great overlap with Terlevich et al. 1991. Additional targets come from the Calan-Tololo an Marseille catalogues. All objects have been observed and analysed homogeneously. We analyse their statistical properties and derive physical conditions (reddening, electron temperature, electron density), as well as chemical abundances.

The evolution of starbursts and their young stellar populations is usually studied using evolutionary population synthesis and photo-ionization calculations. We give a more empirical approach to this issue by appling empirical population synthesis techniques to samples of starburst and H ii galaxies, to measure their evolutionary state and correlate the results with their emission line properties. The results are presented using an evolutionary diagram whose axis are the strengths of the young, intermediate and old age components of the population mix. We also recover the long known prediction that the WHβ and the gas extinction decrease as the starburst ages.

We report the results obtained from VLT-isaac near-IR spectroscopy of two low-luminosity z ≃ 1.9 galaxies located in the core of the lensing cluster AC 114. The amplification factor allowed to obtain, for the first time, physical properties (SFR, abundance ratios, mass, etc.) of star-forming galaxies, 1 - 2 mag fainter than in previous studies of LBGs at z ≈ 3.

Interaction can be the main mechanism that triggers star formation in Wolf-Rayet galaxies. The compact group HCG 31 has one of this objects, NGC 1741. We present new observations of this compact interacting group, in order to analyse the physical conditions and chemical composition of the ionized gas, as well as to estimate the ages of the starbursts.

We present high resolution spectroscopic data of the two giant extragalactic H ii regions NGC 5461 and NGC 5471 in M 101. We calculate the physical conditions in the two nebulae with a large number of diagnostics, and determine their chemical abundances by applying ionization correction factors (icfs) to the observed ionic abundances. The comparison of the icfs based on photo-ionization models (Luridiana & Peimbert 2001; Luridiana et al. 1999) to those computed following the prescriptions by Mathis & Rosa (1991) shows large discrepancies for several elements, including nitrogen, neon and chlorine.

Optically observed ring nebulae and H i cavities around Wolf-Rayet stars have enabled us to obtain information on the history of mass-loss associated with these massive evolved stars. However, such studies have left a number of unanswered questions regarding the amount of mass-loss and the conditions of the stars during a sequence of mass-loss phases. Here we discuss the molecular gas environments of the WR star WR 18, which has an associated optical ring nebula NGC 3199. Our observations show that significant amounts of molecular gas appear close to and associated with the star. Mapping of molecular CO near the star shows that molecular materials appear to substantially avoid areas of optical emission and, instead, form a distorted clumpy shell interior to NGC 3199. Molecular emission lines are broader than lines seen in the interstellar medium and suggest the shell is composed of ejecta. This is further corroborated by the enhanced abundances of molecules containing C, N and O. Implications of the observations for the evolution of WR 18 are discussed.

We present a new approach to probe the properties of the most massive, ionizing stars with respect to the less massive, non-ionizing stars. The new technique utilizes stellar-wind lines, instead of the previously employed nebular lines. This allows us to probe the timescale of the dust dispersal in a very young obscured starburst from purely stellar diagnostics.

The narrow high-speed optical filaments emerging from the Homunculus of η Carinae are modelled as resulting from the passage of ballistic ‘bullets’ of material through the dense circumstellar environment. In this explanation, the string is the decelerating flow of ablated gas from the bullet. Many of the observed properties of the strings are accounted for in this simple model.

From the emission line map in Hα over the full face of the spiral galaxy NGC 3359, we analyze the internal velocity structure of the H ii region population. The emission line profiles show central peaks, with turbulent velocity widths of ≤20 km s–1, and also broad shallow wings, with typical velocities of ~50 km s–1, with respect to the rest velocity of the H ii region. We verify the identification of these wings as due to expanding gas, quantify the energy involved, and suggest physical models for their interpretation, as the effects of mechanical and radiative outflows from the central OB stellar cluster.

We show CO and 13CO maps toward the WR nebulae NGC 2359, NGC 6888 and Anon (WR 134). We determine global parameters and discuss the probable origin of this gas. Nowadays it is becoming clear that molecule formation and survival is be possible around massive evolved stars.

We report the detection and analysis of several molecules arising from the WR nebula NGC 2359 around the WN4 star WR 7 (HD 56925). We have detected 3mm and 1mm rotational lines from 13CO, C18O, HCO+, CS, CN and HCN, and determined lower limits for the SiO. The survey was performed in the southeastern part of the optical nebula, where we previously inferred the presence of dense (104 cm–3) material.