439 research outputs found
Primordial molecular clouds
It is now well known that a primordial chemistry, involving light elements
produced during the nucleosynthesis period, might develop during the hydrogen
post-recombination era. In particular, molecular ions and primordial molecules
such as H2, HD and LiH will be produced. We summarize this primordial chemistry
after the recombination epoch, and then present a simple gravitational collapse
model of a cloud. The potentiality of fragmentation of this collapsing
protoclouds through the thermal instability is also discussed. We suggest that
this study could also be extended to the CO molecule, because the carbon
reservoir molecule CO has already been observed in high redshifts objects.Comment: 12 pages, 1 figures, Invited Talk at 3K Cosmology Conference-Roma
October 9
Big Bang Nucleosynthesis, Cosmic Microwave Background Anisotropies and Dark Energy
Over the last decade, cosmological observations have attained a level of
precision which allows for very detailed comparison with theoretical
predictions. We are beginning to learn the answers to some fundamental
questions, using information contained in Cosmic Microwave Background
Anisotropy (CMBA) data. In this talk, we briefly review some studies of the
current and prospected constraints imposed by CMBA measurements on the neutrino
physics and on the dark energy. As it was already announced by Scott (1999), we
present some possible "new physics" from the Cosmic Microwave Background.Comment: 11 pages, 5 figures, Talk given at 2K1BC Workshop, July 9-12, 2001,
Breuil-Cervinia (Italy
Primordial molecules at millimeter wavelengths
Chemistry plays a particular role in astrophysics. After atomic hydrogen,
helium and their ions, the Universe probably contains more mass in molecules
than in any other species. Molecule formation in the early, pre-galactic
Universe may have had much to do with the formation of galaxies themselves.
In this context the possible interaction between primordial molecules and
photons of the Cosmic Microwave Background is very important through the
theoretical perspectives and constraints which could give some information on
the theory of the large scale structure formation. In this paper we recall the
more recent progresses on the chemistry of the early Universe, and describe the
importance of molecules in the formation phase of proto objects. A special
attention is done concerning the {\it case of LiH.Comment: 8 pages, Talk given at 2K1BC Workshop, July 9-12, 2001,
Breuil-Cervinia (Italy
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