Universe and Metal.
نویسندگان
چکیده
منابع مشابه
Cosmic metal production and the mean metallicity of the Universe
By means of detailed chemo-photometric models for elliptical, spiral and irregular galaxies, we evaluate the cosmic history of the production of chemical elements as well as the metal mass density of the present-day universe. In particular, we study the production rates of some of the most common chemical species (O, Mg, N, Si, Fe, Zn), detected both in local stars, galactic and extragalactic H...
متن کاملStar Formation and Metal Production in the Early Universe
Recent advances in our understanding of star formation and the associated production of heavy elements at high redshift are reviewed. First, the host galaxies of star-formation regions at redshift 2 – 4 are characterized, and a comparison with their local counterparts is made. Then the properties of the stellar content in these objects are summarized. A major theme is the interaction and feedba...
متن کاملOccurrence of Metal-free Galaxies in the Early Universe
The character of the first galaxies at redshifts z > ∼ 10 strongly depends on their level of pre-enrichment, which is in turn determined by the rate of primordial star formation prior to their assembly. In order for the first galaxies to remain metal-free, star formation in minihaloes must be highly suppressed, most likely by H2-dissociating LymanWerner (LW) radiation. We show that the build-up...
متن کاملThe Main Epoch of Metal Production in the Universe
Clusters of galaxies allow a direct estimate of the metallicity and metal production yield on the largest scale so far. It is argued that cluster metallicity (∼ 1/3 solar) should be taken as representative of the low-z universe as a whole. There is now compelling evidence that the bulk of stars not only in cluster ellipticals but also in field ellipticals and bulges formed at high redshifts (z ...
متن کاملTwo populations of metal-free stars in the early Universe
We construct star formation histories at redshifts z & 5 for two physically distinct populations of primordial, metal-free stars, motivated by theoretical and observational arguments that have hinted towards the existence of an intermediate stellar generation between Population III and Population I/II. Taking into account the cosmological parameters as recently revised by WMAP after three years...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Materia Japan
سال: 1997
ISSN: 1340-2625,1884-5843
DOI: 10.2320/materia.36.747