Constraining non standard recombination: a worked example

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We fit the BOOMERANG, MAXIMA and COBE/DMR measurements of the cosmic microwave background anisotropy in spatially flat cosmological models where departures from standard recombination of the primeval plasma are parametrized through a change in the fine structure constant α compared to its present va...

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Autores principales: Landau, Susana Judith, Harari, Diego D., Zaldarriaga, Matías
Formato: Articulo Preprint
Lenguaje:Inglés
Publicado: 2001
Materias:
Ciencias Astronómicas
Geofísica
Astronomía
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/2052
http://arxiv.org/pdf/astro-ph/0010415v2.pdf
http://journals.aps.org/prd/abstract/10.1103/PhysRevD.63.083505
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-2052
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Astronómicas
Geofísica
Astronomía
spellingShingle Ciencias Astronómicas
Geofísica
Astronomía
Landau, Susana Judith
Harari, Diego D.
Zaldarriaga, Matías
Constraining non standard recombination: a worked example
topic_facet Ciencias Astronómicas
Geofísica
Astronomía
description We fit the BOOMERANG, MAXIMA and COBE/DMR measurements of the cosmic microwave background anisotropy in spatially flat cosmological models where departures from standard recombination of the primeval plasma are parametrized through a change in the fine structure constant α compared to its present value. In addition to α we vary the baryon and dark matter densities, the spectral index of scalar fluctuations, and the Hubble constant. Within the class of models considered, the lack of a prominent second acoustic peak in the measured spectrum can be accomodated either by a relatively large baryon density, by a tilt towards the red in the spectrum of density fluctuations, or by a delay in the time at which neutral hydrogen formed. The ratio between the second and first peak decreases by around 25% either if the baryon density Ωbh 2 is increased or the spectral index n decreased by a comparable amount, or if neutral hydrogen formed at a redshift z∗ about 15% smaller than its standard value. We find that the present data is best fitted by a delay in recombination, with a lower baryon density than the best fit if recombination is standard. Our best fit model has z∗ = 900, Ωbh 2 = 0.024, Ωmh 2 = 0.14, H0 = 49 and n = 1.02. Compatible with present data at 95% confidence level 780 < z∗ < 1150, 0.018 < Ωbh 2 < 0.036, 0.07 < Ωmh 2 < 0.3 and 0.9 < n < 1.2.
format Articulo
Preprint
author Landau, Susana Judith
Harari, Diego D.
Zaldarriaga, Matías
author_facet Landau, Susana Judith
Harari, Diego D.
Zaldarriaga, Matías
author_sort Landau, Susana Judith
title Constraining non standard recombination: a worked example
title_short Constraining non standard recombination: a worked example
title_full Constraining non standard recombination: a worked example
title_fullStr Constraining non standard recombination: a worked example
title_full_unstemmed Constraining non standard recombination: a worked example
title_sort constraining non standard recombination: a worked example
publishDate 2001
url http://sedici.unlp.edu.ar/handle/10915/2052
http://arxiv.org/pdf/astro-ph/0010415v2.pdf
http://journals.aps.org/prd/abstract/10.1103/PhysRevD.63.083505
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