Thermal history constraints on the isocurvature baryon model

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view Abstract Citations (45) References (29) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Thermal History Constraints on the Isocurvature Baryon Model Hu, Wayne ; Sugiyama, Naoshi Abstract We present a thorough and detailed investigation of baryon isocurvature models including realistic thermal histories, \ie, late or partial reionization of the universe and compact object formation after standard recombination. Constraints on these models are imposed from spectral distortion in the cosmic microwave background (CMB), number fluctuations in galaxy counts $\sigma_8$, and recent CMB anisotropy observations. Since the status of degree scale anisotropies is as yet unclear, the lack of spectral distortions is the most serious constraint on the spectral index of initial fluctuations: $-1.2 \simlt n \simlt -0.5$ in partially ionized models and $-1.2 \simlt n \simlt -0.9$ in compact object dominated universes in order to avoid significant bias in galaxy formation. Full ionization of the universe before $z = 300$ is also forbidden by this constraint. Intermediate scale CMB fluctuations which are significantly larger than standard CDM is a {\it robust} prediction of these models. Many models are consequently in conflict with the recent degree scale detections by Python, ARGO, and MSAM, \eg, compact object dominated models with $\Omega_0 \simlt 0.2$. Moreover, {\it all} models will be ruled out if the low CMB fluctuations on degree scales as detected by the SP91 13 point scan are confirmed. On the other hand, most models fare well compared with the high Tenerife and MAX detections. Publication: The Astrophysical Journal Pub Date: December 1994 DOI: 10.1086/174921 arXiv: arXiv:astro-ph/9403031 Bibcode: 1994ApJ...436..456H Keywords: Astronomical Models; Background Radiation; Baryons; Cosmology; Extraterrestrial Radio Waves; Galactic Evolution; Thermal Analysis; Universe; Anisotropy; Cosmic Background Explorer Satellite; Dark Matter; Galactic Clusters; Mathematical Models; Radio Astronomy; Spaceborne Astronomy; Astrophysics; COSMOLOGY: COSMIC MICROWAVE BACKGROUND; COSMOLOGY: LARGE-SCALE STRUCTURE OF UNIVERSE; COSMOLOGY: THEORY; Astrophysics E-Print: 18pgs, uuencoded tarred postscript, CfPA-TH-94-16, UTAP-178 full text sources arXiv | ADS |