Squeezing the window on isocurvature modes with the Lyman-{alpha} forest
- Departamento de Fisica Teorica C-XI, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain)
- Laboratoire de Physique Theorique LAPTH, F-74941 Annecy-le-Vieux Cedex (France)
- 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, Vol. 72, Issue 10; Other Information: DOI: 10.1103/PhysRevD.72.103515; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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