Related papers: A continuous low star formation rate in IZw 18 ?
Recent spectroscopic observations of IZw~18 have revealed homogeneous abundance throughout the galaxy and several observations of other starburst galaxies have shown no significant gradient or discontinuity in the abundance distributions…
It has been suggested that a continuous low star formation rate has been the dominant regime in IZw 18 and in dwarf galaxies for the lifetime of these objects (Legrand et al. 1999). Here, we discuss and model various star-forming histories…
New spectroscopic observations of the metal poor galaxy IZw 18 are discussed. Wolf-Rayet stars of WC type have been detected in the NW-HII region contrary to evolutionary synthesis model predictions. Implications on the mass loss rate and…
Observations of quiescent dwarfs and low surface brightness galaxies suggest that continuous low rate star formation is likely to occur, during the quiescent phases between bursts, in dwarf galaxies. We thus have used a spectrophotometric…
We present sensitive molecular line observations of the metal-poor blue compact dwarf I Zw 18 obtained with the IRAM Plateau de Bure interferometer. These data constrain the CO J=1-0 luminosity within our 300 pc (FWHM) beam to be L_CO < 1…
We have derived the star formation history (SFH) of the blue compact dwarf galaxy IZw18 through comparison of deep HST/ACS data with synthetic color magnitude diagrams. A statistical analysis was implemented for the identification of the…
In this paper we present some results concerning the effects of two instantaneous starbursts, separated by a quiescent period, on the dynamical and chemical evolution of blue compact dwarf galaxies. In particular, we compare the model…
IZw18, a blue compact dwarf (BCD) galaxy with the 2nd lowest metallicity measured in a star-forming object, has been observed with all three instruments on board the Spitzer Space Telescope. We present the deepest 5-36 micron mid-infrared…
Local metal-poor galaxies are ideal analogues of primordial galaxies with the interstellar medium (ISM) barely being enriched with metals. However, it is unclear whether carbon monoxide remains a good tracer and coolant of molecular gas at…
Wolf-Rayet stars (WR) have been detected in the NW region of the metal-poor starburst galaxy IZw 18. The integrated luminosity and FWHM of the bumps at 4650 A and 5808 A are consistent with the presence of a few individual stars of WC4 or…
We present observations of the nearby extremely metal-poor galaxy I Zw 18 using the Keck Cosmic Web Imager (KCWI) and the JWST Mid-InfraRed Instrument (MIRI) Integral Field Spectrographs (IFS). From optical and mid-IR oxygen emission lines,…
We present new measurements of the gas-phase C/O abundance ratio in both the NW and SE components of the extremely metal-poor dwarf irregular galaxy I Zw 18, based on ultraviolet spectroscopy of the two H II regions using the Faint Object…
Chemically homogeneously evolving stars have been proposed to account for several exotic phenomena, including gravitational-wave emissions and gamma-ray bursts. Here we study whether these stars can explain the metal-poor dwarf galaxy I…
We have combined measurements of the kinematics, morphology, and oxygen abundance of the ionized gas in \IZw18, one of the most metal-poor galaxies known, to examine the star formation history and chemical mixing processes.
Blue Compact Dwarf and Dwarf Irregular galaxies are generally believed to be unevolved objects, due to their blue colors, compact appearance and large gas fractions. Many of these objects show an ongoing intense burst of star formation or…
We present a detailed 2D study of the ionized ISM of IZw18 using new PMAS-IFU optical observations. IZw18 is a high-ionization galaxy which is among the most metal-poor starbursts in the local Universe. This makes IZw18 a local benchmark…
We report on new FUSE far-UV spectroscopy of the most metal-poor blue compact dwarf galaxy I Zw 18. The new data represent an improvement over previous FUSE spectra by a factor of 1.7 in the signal-to-noise. Together with a larger spectral…
We present a JWST imaging survey of I Zw 18, the archetypal extremely metal-poor, star-forming (SF), blue compact dwarf galaxy. With an oxygen abundance of only $\sim$3% $Z_{\odot}$, it is among the lowest-metallicity systems known in the…
Abridged. Low-metallicity star-forming dwarf galaxies are prime targets to understand the chemical enrichment of the interstellar medium. The HI region provides important constraints on the dispersal and mixing of heavy elements released by…
We present JWST/MIRI spectra from the Medium-Resolution Spectrometer of IZw18, a nearby dwarf galaxy with a metallicity of $\sim$3% Solar. Its proximity enables a detailed study of highly ionized gas that can be interpreted in the context…