期刊
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
卷 -, 期 7, 页码 -出版社
IOP PUBLISHING LTD
DOI: 10.1088/1475-7516/2010/07/012
关键词
supernova type Ia - standard candles; CMBR theory
资金
- Korea Ministry of Education, Science and Technology (MEST)
- Korea Institute for Advanced Study
- Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan
- Ministry of Education, Science, Sports and Culture [21540276]
- JSPS [21244033, 19GS0219]
- National Research Foundation of Korea [52314001] Funding Source: Korea Institute of Science & Technology Information (KISTI), National Science & Technology Information Service (NTIS)
- Grants-in-Aid for Scientific Research [21540276] Funding Source: KAKEN
Acoustic peaks in the spectrum of the cosmic microwave background in spherically symmetric inhomogeneous cosmological models are studied. At the photon-baryon decoupling epoch, the universe may be assumed to be dominated by non-relativistic matter, and thus we may treat radiation as a test field in the universe filled with dust which is described by the Lemaitre-Tolman-Bondi (LTB) solution. First, we give an LTB model whose distance-redshift relation agrees with that of the concordance Lambda CDM model in the whole red-shift domain and which is well approximated by the Einstein-de Sitter universe at and before decoupling. We determine the decoupling epoch in this LTB universe by Gamow's criterion and then calculate the positions of acoustic peaks. Thus obtained results are not consistent with the WMAP data. However, we find that one can fit the peak positions by appropriately modifying the LTB model, namely, by allowing the deviation of the distance-redshift relation from that of the concordance Lambda CDM model at z > 2 where no observational data are available at present. Thus there is still a possibility of explaining the apparent accelerated expansion of the universe by inhomogeneity without resorting to dark energy if we abandon the Copernican principle. Even if we do not take this extreme attitude, it also suggests that local, isotropic inhomogeneities around us may seriously affect the determination of the density contents of the universe unless the possible existence of such inhomogeneities is properly taken into account.
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