相关论文: The baryon content of the Universe

Stars and gas in galaxies, hot intracluster medium, and intergalactic photo-ionized gas make up at most half of the baryons that are expected to be present in the universe. The majority of baryons are still missing and are expected to be…

In the Big Bang about 5% of the mass that was created was in the form of normal baryonic matter (neutrons and protons). Of this about 10% ended up in galaxies in the form of stars or of gas (that can be in molecules, can be atomic, or can…

Big-bang nucleosynthesis is one of the cornerstones of the standard cosmology. For almost thirty years its predictions have been used to test the big-bang model to within a fraction of a second of the bang. The concordance that exists…

A fair and complete accounting of cosmic baryons now appears possible, because most of them are in states which are either directly observable or reliably constrained by indirect arguments. More than three-quarters of the baryons are…

The comparison of cosmic abundances of the light elements with the density of baryonic stars and gas in the universe today provides a critical test of big bang theory and a powerful probe of the nature of dark matter. A new technique allows…

We show that the high local baryonic fraction, M(bar) ~ 1/3 M(tot), found in groups and clusters of galaxies does not reconcile the observed cosmological baryon density with the standard Big-Bang prediction. Taking into account recent…

We make an inventory of the baryonic and gravitating mass in structures ranging from the smallest galaxies to rich clusters of galaxies. We find that the fraction of baryons converted to stars reaches a maximum between M500 = 1E12 and 1E13…

Approximately half of the Universe's dark matter resides in collapsed halos; significantly less than half of the baryonic matter (protons and neutrons) remains confined to halos. A small fraction of baryons are in stars and the interstellar…

Observations of clusters of galaxies suggest that they contain significantly fewer baryons (gas plus stars) than the cosmic baryon fraction. This `missing baryon' puzzle is especially surprising for the most massive clusters which are…

The angular power spectrum and polarization of the cosmic microwave background radiation (CMB), the relative abundances of primordial hydrogen, deuterium and helium isotopes, and the large-scale structure of the universe all indicate that…

The hot, diffuse gas that fills the largest overdense structures in the Universe -- clusters of galaxies and a web of giant filaments connecting them -- provides us with tools to address a wide array of fundamental astrophysical and…

Nucleosynthesis in the standard hot big bang cosmology offers a successful account of the production of the light nuclides during the early evolution of the Universe. Consistency among the predicted and observed abundances of D, $^3$He,…

Groups and clusters of galaxies occupy a special position in the hierarchy of large-scale cosmic structures because they are the largest and the most massive (from ~10^13 Msun to over 10^15 Msun) objects in the universe that have had time…

The light element abundances probe the baryon density of the universe within a few minutes of the Big Bang. Of these relics from the earliest universe, deuterium is the baryometer of choice. By comparing its primordial abundance inferred…

The recently observed Deuterium abundance in a low- metallicity high-redshift hydrogen cloud, which is about ten times larger than that observed in the near interstellar medium, is that expected from the Standard Big Bang Nucleosynthesis…

About 80\% of the mass of the present Universe is made up of the unknown (dark matter), while the rest is made up of ordinary matter. It is a very intriguing question why the {\it mass} densities of dark matter and ordinary matter (mainly…

The relic abundance of baryons - the only form of stable matter whose existence we are certain of - is a crucial parameter for many cosmological processes, as well as material evidence that there is new physics beyond the Standard Model. We…

The relic abundances of the light elements synthesized during the first few minutes of the evolution of the Universe provide unique probes of cosmology and the building blocks for stellar and galactic chemical evolution, while also enabling…

Thanks to the accurate determination of the baryon density of the universe by the recent cosmic microwave background experiments, updated predictions of the standard model of Big Bang nucleosynthesis now yield the initial abundance of the…

A key pillar of modern cosmology, Big Bang Nucleosynthesis (BBN) offers a probe of the particle content and expansion rate of the Universe a mere few minutes after the beginning. When compared with the BBN predictions, the observationally…