4 research outputs found
The Quintessential CMB, Past & Future
The past, present and future of cosmic microwave background (CMB) anisotropy
research is discussed, with emphasis on the Boomerang and Maxima balloon
experiments. These data are combined with large scale structure (LSS)
information and high redshift supernova (SN1) observations to explore the
inflation-based cosmic structure formation paradigm. Here we primarily focus on
a simplified inflation parameter set, {omega_b,omega_{cdm},Omega_{tot},
Omega_Q,w_Q, n_s,tau_C, sigma_8}. After marginalizing over the other cosmic and
experimental variables, we find the current CMB+LSS+SN1 data gives
Omega_{tot}=1.04\pm 0.05, consistent with (non-baroque) inflation theory.
Restricting to Omega_{tot}=1, we find a nearly scale invariant spectrum, n_s
=1.03 \pm 0.07. The CDM density, omega_{cdm}=0.17\pm 0.02, is in the expected
range, but the baryon density, omega_b=0.030\pm 0.004, is slightly larger than
the current nucleosynthesis estimate. Substantial dark energy is inferred,
Omega_Q\approx 0.68\pm 0.05, and CMB+LSS Omega_Q values are compatible with the
independent SN1 estimates. The dark energy equation of state, parameterized by
a quintessence-field pressure-to-density ratio w_Q, is not well determined by
CMB+LSS (w_Q<-0.3 at 95%CL), but when combined with SN1 the resulting w_Q<-0.7
limit is quite consistent with the w_Q=-1 cosmological constant case. Though
forecasts of statistical errors on parameters for current and future
experiments are rosy, rooting out systematic errors will define the true
progress.Comment: 14 pages, 3 figs., in Proc. CAPP-2000 (AIP), CITA-2000-6
The Cosmic Background Radiation circa nu2K
We describe the implications of cosmic microwave background (CMB)
observations and galaxy and cluster surveys of large scale structure (LSS) for
theories of cosmic structure formation, especially emphasizing the recent
Boomerang and Maxima CMB balloon experiments. The inflation-based cosmic
structure formation paradigm we have been operating with for two decades has
never been in better shape. Here we primarily focus on a simplified inflation
parameter set, {omega_b,omega_{cdm},Omega_{tot}, Omega_\Lambda,n_s,\tau_C,
\sigma_8}. Combining all of the current CMB+LSS data points to the remarkable
conclusion that the local Hubble patch we can access has little mean curvature
(Omega_{tot}=1.08\pm 0.06) and the initial fluctuations were nearly scale
invariant (n_s=1.03\pm 0.08), both predictions of (non-baroque) inflation
theory. The baryon density is found to be slightly larger than that preferred
by independent Big Bang Nucleosynthesis estimates (omega_b=0.030\pm 0.005 cf.
0.019\pm 0.002). The CDM density is in the expected range (omega_{cdm}=0.17 \pm
0.02). Even stranger is the CMB+LSS evidence that the density of the universe
is dominated by unclustered energy akin to the cosmological constant
(Omega_\Lambda=0.66\pm 0.06), at the same level as that inferred from high
redshift supernova observations. We also sketch the CMB+LSS implications for
massive neutrinos.Comment: 7 pages, 4 figs., in Proc. Neutrino 2000 (Elsevier), CITA-2000-6