Results 201 to 210 of about 58,855 (236)
Some of the next articles are maybe not open access.
The chemical evolution of galaxies
Vistas in Astronomy, 1975Abstract Emphasis is placed on the simplest models of the chemical evolution of galaxies, and the role played by the concentration of the interstellar gas to gravitational stable regions is taken into account. Although Schmidt's simple model is improved when concentration is allowed for, it still predicts too wide a spread of metal abundances for ...
openaire +2 more sources
The Chemical Evolution of Dwarf Galaxies
Astrophysics and Space Science, 2001Various observations of dwarf starburst galaxies have revealed homogeneous abundance within the ionized region suggesting that the measured metallicities do not result from the metals ejected during the current burst (because they should not have time to mix homogeneously at such large scale) but from previous star formation episodes.
openaire +2 more sources
Chemical Evidence for Evolution of Galaxies
Astrophysics and Space Science, 2001I have compiled the very best data published on abundance gradients. From this sample of 29 galaxies, some information can be gained on the mecanism of morphological evolution in disk galaxies. From this sample, I find that early-type galaxies show an identical trend in the behavior of extrapolated central abundance versus morphological type to that ...
openaire +2 more sources
Elliptical Galaxy Chemical Evolution [PDF]
, 1999 Conclusions about elliptical and other early-type galaxies come from studies of integrated starlight and studies of giant stars in the nearest galaxies. The abundance distribution for all galaxy types at all radii appears to exhibit a “G dwarf problem” in that the distribution is more strongly peaked than the one-zone closed-box constantyield ...
openaire +1 more source
Cosmic chemical evolution and the evolution of galaxies
AIP Conference Proceedings, 2000The evolutionary history of star and element formation rates with cosmic epoch is reviewed. The problem of taking proper account of the effects of dust obscuration in optical and ultraviolet observations is emphasised. Recent submillimetre surveys have been used to derive the star formation rate as a function of cosmic epoch independent of dust ...
openaire +2 more sources
Chemical Abundances and Galaxy Evolution [PDF]
, 1984 The chemical abundance characteristics of two comparatively structurally simple classes of galaxies, the ellipticals and irregulars, are briefly reviewed. Neither of these types of galaxies have properties which are fully consistent with the quantitative predictions of basic chemical evolution models. Possible sources for discrepancies are discussed in
openaire +1 more source
The Chemical and Dynamical Evolution of the Galaxy
Publications of the Astronomical Society of the Pacific, 1993Theoretical models of the chemical and dynamical evolution of galaxies are developed and a Galactic structure survey is presented -- both are invaluable tools for uncovering the history of the formation of our Galaxy. Important advances in my theoretical models are non-instantaneous recycling of newly synthesized elements such as iron from Type Ia ...
openaire +2 more sources
Problems in the Chemical Evolution of Galaxies
1984The chemical evolution of a galaxy is governed by the evolution of individual stars as well as collective processes such as star formation rate, stellar mass function and dynamics of the gas-stars system. Such a problem has been the subject of a great deal of work as reported in many up to date reviews, among which we recall Tinsley (1980), Pagel and ...
C. Chiosi, F. Matteucci
openaire +2 more sources
Nucleosynthesis and Chemical Evolution of Galaxies
1983This chapter deals with a brief presentation of the nucleosynthesis processes which are responsible for the formation of the observed chemical elements : the primordial nucleosynthesis occurring just after the Big Bang, responsible for the formation of D, 3He,4 He and at least in part 7Li; the bombardment of the interstellar medium by galactic cosmic ...
openaire +2 more sources
Chemical Evolution of Irregular Galaxies
2011In this chapter, we describe the properties of irregular galaxies and the proposed chemical evolution models. Irregular galaxies are generally small and rather simple objects with low metallicity and large gas content, suggesting that they are either young objects or have undergone discontinuous star formation activity (bursts) or a continuous but not ...
openaire +2 more sources