摘要:

This paper summarizes the results from the COBE satellite mission. Nine years have passed since the launch of COBE and six years since the announcement of the discovery of cosmic microwave background anisotropies by the COBE DMR instrument. This is still a relatively short time to look back and understand the implications of COBE and the anisotropy discovery; however, this 3K Cosmology Conference provides some context. The Cosmic Background Explorer (COBE) satellite has made a major contribution to the field of cosmology and has help create the confidence and high level of interest that propels the field today. Two major CMB observations, the thermal spectrum of the CMB and the CMB anisotropies, plus a host of other observations and conclusions are the basis and a major but not exclusive portion of the legacy of COBE. The recent detection and observation of the cosmic infrared background (CIB) are also part of COBE’s major contribution to cosmology. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.59326

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

Various issues concerning the impact of inflationary models on parameter estimation from the cosmic microwave background are reviewed, with particular focus on the range of possible outcomes of inflationary models and on the amount which might be learnt about inflation from the microwave background. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.59318

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

We investigate the global texture model of structure formation in cosmogonies with non-zero cosmological constant for different values of the Hubble parameter. We find that the absence of significant acoustic peaks and little power on large scales are robust predictions of these models. However, from a careful comparison with experiments we conclude that at present we cannot safely reject the model on the grounds of published CMB anisotropy data. If bias is close to one on large scales, galaxy correlation data rules out the models. New, very stringent constraints come from peculiar velocities. Investigating the large-Nlimit, we argue that our main conclusions apply to all globalO(N)models of structure formation. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.59325

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

Recent developments in inflation model building, based on supersymmetry, have produced compelling models in which strings are produced at the end of inflation. In such models the cosmological perturbations are seeded both by the defects and by the quantum fluctuations. We show that such models produce qualitatively new and desirable predictions for CMB anisotropies and the CDM power spectrum. This remark should put an end to the long term animosity between defect and inflationary scenarios of structure formation. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.59339

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

I discuss some recent developments in string cosmology. The first is based on the low energy string action in a pre big bang cosmology in which the dynamics of the massless fields (dilation, graviton, moduli and axion) play a pivotal role, leading to a period of inflation and the possibility of a spectrum of near scale invariant density perturbations. The second is a method to dynamically stabilize the dilaton through the presence of non-perturbative gaugino condensates in a supergravity action. It relies on the presence of exponential potentials which lead to cosmological scaling solutions. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.59340

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

We examine some new aspect of “Quintessence” models, where a minimally-coupled scalar field is thought to be a suitable candidate for the missing energy in the Universe. In particular, we give emphasis on the problem of initial conditions, finding the values of the scalar field and of its first time derivative that realize initial adiabaticity or initial isocurvature. Starting from the corresponding initial conditions, we numerically solve the background equations and the perturbed Einstein equations, in order to obtain the CMB anisotropies spectra and to compare them with that predicted by the ordinary Cold Dark Matter model(&OHgr;m=1).We find characteristic signatures of the scalar field that could be detected by future satellite missions. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.59341

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

DAMA is searching for Dark Matter particles deep underground in the Gran Sasso National Laboratory by using several kinds of scintillators, acting as target-detectors; recent results are here summarized. In particular, the new DAMA/NaI-2 result (14962 kg⋅day) on the WIMP annual modulation signature achieved by the ≃100 kg highly radiopure NaI(Tl) set-up is summarized. It turns out to be consistent with the DAMA/NaI-1 result (4549 kg⋅day) and a combined maximum likelihood analysis of the two data sets (19511 kg⋅day) favours at 99.6&percent; C.L. the hypothesis of presence of an annual modulation of the rate in the energy region of interest for Dark Matter direct detection. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.59342

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

Sterile neutrinos have been invoked in attempts to use neutrino oscillations to account for several experimental anomalies, the most recently confirmed being the atmospheric anomaly announced by the SuperKamiokande collaboration. In this talk I describe the development and its relevance for both big bang nucleosynthesis and the CMB. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.59343

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

We explore the possibility that a multiple-stage inflationary scenario based on supersymmetric GUT models, can account for the break atkb≃0.05 h&hthinsp;Mpc−1in the power spectrum of galaxy clustering, while it reproduces the angular power spectrum of cosmic microwave background anisotropies. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.59346

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

In the standard Big Bang model, the light elements in the cosmos -hydrogen and helium but also deuterium and lithium- were created in the very early Universe. The main problem is to connect what we can actually observe to day with the standard Big Bang nucleosynthesis predictions essentially because of uncertainties in modeling their evolution since the Big Bang. After a brief review of the primordial nucleosynthesis -predictions and observations of the primordial abundances- we present the preliminary studies of the primordial chemistry: molecular formation and evolution in the early Universe. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.59344

出版商:AIP    

年代:1999

数据来源: AIP