Squeezing the window on isocurvature modes with the Lyman-{alpha} forest

Journal Article · Tue Nov 15 04:00:00 EST 2005 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PhysRevD.72.103515· OSTI ID:20711542

Beltran, Maria ^[1]; Garcia-Bellido, Juan ^[1]; Lesgourgues, Julien ^[2]; Viel, Matteo ^[3]

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1. Departamento de Fisica Teorica C-XI, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain)
2. Laboratoire de Physique Theorique LAPTH, F-74941 Annecy-le-Vieux Cedex (France)
3. Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom)

Various recent studies proved that cosmological models with a significant contribution from cold dark matter isocurvature perturbations are still compatible with most recent data on cosmic microwave background anisotropies and on the shape of the galaxy power spectrum, provided that one allows for a very blue spectrum of primordial entropy fluctuations (n{sub iso}>2). However, such models predict an excess of matter fluctuations on small scales, typically below 40h{sup -1} Mpc. We show that the proper inclusion of high-resolution high signal-to-noise Lyman-{alpha} forest data excludes most of these models. The upper bound on the isocurvature fraction {alpha}=f{sub iso}{sup 2}/(1+f{sub iso}{sup 2}), defined at the pivot scale k{sub 0}=0.05 Mpc{sup -1}, is pushed down to {alpha}<0.4, while n{sub iso}=1.9{+-}1.0 (95% confidence limits). We also study the bounds on curvaton models characterized by maximal correlation between curvature and isocurvature modes, and a unique spectral tilt for both. We find that f{sub iso}<0.05 (95% C.L.) in that case. For double-inflation models with two massive inflatons coupled only gravitationally, the mass ratio should obey R<3 (95% C.L.)

• OSTI ID: 20711542
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 10 Vol. 72; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANISOTROPY
CORRELATIONS
COSMIC RADIATION
COSMOLOGY
DISTURBANCES
ENERGY SPECTRA
ENTROPY
FLUCTUATIONS
GALAXIES
INFLATIONARY UNIVERSE
NOISE
NONLUMINOUS MATTER
RADIOWAVE RADIATION
RELICT RADIATION