Imperial College London
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ProfessorAlanHeavens

Faculty of Natural Sciences, Department of Physics

Chair in Astrostatistics
 
 
 
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Contact

 

+44 (0)20 7594 2930a.heavens Website

 
 
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Location

 

1018EBlackett LaboratorySouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Verde:2017:04/023,
author = {Verde, L and Bellini, E and Pigozzo, C and Heavens, AF and Jimenez, R},
doi = {04/023},
journal = {JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS},
title = {Early cosmology constrained},
url = {http://dx.doi.org/10.1088/1475-7516/2017/04/023},
volume = {2017},
year = {2017}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - We investigate our knowledge of early universe cosmology by exploring how much additional energy density can be placed in different components beyond those in the ΛCDM model. To do this we use a method to separate early- and late-universe information enclosed in observational data, thus markedly reducing the model-dependency of the conclusions. We find that the 95% credibility regions for extra energy components of the early universe at recombination are: non-accelerating additional fluid density parameter ΩMR < 0.006 and extra radiation parameterised as extra effective neutrino species 2.3 < Neff < 3.2 when imposing flatness. Our constraints thus show that even when analyzing the data in this largely model-independent way, the possibility of hiding extra energy components beyond ΛCDM in the early universe is seriously constrained by current observations. We also find that the standard ruler, the sound horizon at radiation drag, can be well determined in a way that does not depend on late-time Universe assumptions, but depends strongly on early-time physics and in particular on additional components that behave like radiation. We find that the standard ruler length determined in this way is rs = 147.4 ± 0.7 Mpc if the radiation and neutrino components are standard, but the uncertainty increases by an order of magnitude when non-standard dark radiation components are allowed, to rs = 150 ± 5 Mpc.
AU  - Verde,L
AU  - Bellini,E
AU  - Pigozzo,C
AU  - Heavens,AF
AU  - Jimenez,R
DO  - 04/023
PY  - 2017///
SN  - 1475-7516
TI  - Early cosmology constrained
T2  - JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
UR  - http://dx.doi.org/10.1088/1475-7516/2017/04/023
UR  - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000401806200023&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
UR  - http://hdl.handle.net/10044/1/48091
VL  - 2017
ER  -
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