Applications of Wavelets to the Analysis of Cosmic Microwave Background Maps

We consider wavelets as a tool to perform a variety of tasks in the context of analyzing cosmic microwave background (CMB) maps. Using Spherical Haar Wavelets we define a position and angular-scale-dependent measure of power that can be used to assess the existence of spatial structure. We apply planar Daubechies wavelets for the identification and removal of points sources from small sections of sky maps. Our technique can successfully identify virtually all point sources which are above 3 sigma and more than 80% of those above 1 sigma. We discuss the trade-offs between the levels of correct and false detections. We denoise and compress a 100,000 pixel CMB map by a factor of about 10 in 5 seconds achieving a noise reduction of about 35%. In contrast to Wiener filtering the compression process is model independent and very fast. We discuss the usefulness of wavelets for power spectrum and cosmological parameter estimation. We conclude that at present wavelet functions are most suitable for identifying localized sources.Comment: 10 pages, 6 figures. Submitted to MNRA

Two hundred fifty years of aerosols and climate: the end of the age of aerosols

Carbonaceous and sulfur aerosols have a substantial global and regional influence on climate, resulting in a net cooling to date, in addition to their impact on health and ecosystems. The magnitude of this influence has changed substantially over the past and is expected to continue to change into the future. An integrated picture of the changing climatic influence of black carbon, organic carbon and sulfate over the period 1850 through 2100, focusing on uncertainty, is presented using updated historical inventories and a coordinated set of emission projections. We describe, in detail, the aerosol emissions from the RCP4.5 scenario and its associated reference scenario. While aerosols have had a substantial impact on climate over the past century, we show that, by the end of the 21st century, aerosols will likely be only a minor contributor to radiative forcing due to increases in greenhouse gas forcing and a net global decrease in pollutant emissions. This outcome is even more certain under a successful implementation of a policy to limit greenhouse gas emissions as low-carbon energy technologies that do not emit appreciable aerosol or SO₂ are deployed

The Diversity of Extrasolar Terrestrial Planets

Extrasolar planetary host stars are enriched in key planet-building elements. These enrichments have the potential to drastically alter the building blocks available for terrestrial planet formation. Here we report on the combination of dynamical models of late-stage terrestrial planet formation within known extrasolar planetary systems with chemical equilibrium models of the composition of solid material within the disk. This allows us to constrain the bulk elemental composition of extrasolar terrestrial planets. A wide variety of resulting planetary compositions exist, ranging from those that are essentially "Earth-like", containing metallic Fe and Mg-silicates, to those that are dominated by graphite and SiC. This implies that a diverse range of terrestrial planets are likely to exist within extrasolar planetary systems.Comment: 4 pages, 1 figure. Submitted to the proceedings of IAU symposium 265 Chemical Abundances in the Universe: Connecting First Stars to Planet

Binary Central Stars of Planetary Nebulae Discovered Through Photometric Variability III: The Central Star of Abell 65

A growing number of close binary stars are being discovered among central stars of planetary nebulae. Recent and ongoing surveys are finding new systems and contributing to our knowledge of the evolution of close binary systems. The push to find more systems was largely based on early discoveries which suggested that 10 to 15% of all central stars are close binaries. One goal of this series of papers is confirmation and classification of these systems as close binaries and determination of binary system parameters. Here we provide time-resolved multi-wavelength photometry of the central star of Abell 65 as well as further analysis of the nebula and discussion of possible binary--nebula connections. Our results for Abell 65 confirm recent work showing that it has a close, cool binary companion, though several of our model parameters disagree with the recently published values. With our longer time baseline of photometric observations from 1989--2009 we also provide a more precise orbital period of 1.0037577 days.Comment: Accepted for publication in the Astronomical Journa

The Cosmic Microwave Background & Inflation, Then & Now

Boomerang, Maxima, DASI, CBI and VSA significantly increase the case for accelerated expansion in the early universe (the inflationary paradigm) and at the current epoch (dark energy dominance), especially when combined with data on high redshift supernovae (SN1) and large scale structure (LSS). There are ``7 pillars of Inflation'' that can be shown with the CMB probe, and at least 5, and possibly 6, of these have already been demonstrated in the CMB data: (1) a large scale gravitational potential; (2) acoustic peaks/dips; (3) damping due to shear viscosity; (4) a Gaussian (maximally random) distribution; (5) secondary anisotropies; (6) polarization. A 7th pillar, anisotropies induced by gravity wave quantum noise, could be too small. A minimal inflation parameter set, \omega_b,\omega_{cdm}, \Omega_{tot}, \Omega_Q,w_Q,n_s,\tau_C, \sigma_8}, is used to illustrate the power of the current data. We find the CMB+LSS+SN1 data give \Omega_{tot} =1.00^{+.07}_{-.03}, consistent with (non-baroque) inflation theory. Restricting to \Omega_{tot}=1, we find a nearly scale invariant spectrum, n_s =0.97^{+.08}_{-.05}. The CDM density, \Omega_{cdm}{\rm h}^2 =.12^{+.01}_{-.01}, and baryon density, \Omega_b {\rm h}^2 = >.022^{+.003}_{-.002}, are in the expected range. (The Big Bang nucleosynthesis estimate is 0.019\pm 0.002.) Substantial dark (unclustered) 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, crudely parameterized by a quintessence-field pressure-to-density ratio w_Q, is not well determined by CMB+LSS (w_Q < -0.4 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.Comment: 20 pages, 8 figures, in Theoretical Physics, MRST 2002: A Tribute to George Libbrandt (AIP), eds. V. Elias, R. Epp, R. Myer

The Sunyaev-Zeldovich effect in CMB-calibrated theories applied to the Cosmic Background Imager anisotropy power at l > 2000

We discuss the nature of the possible high-l excess in the Cosmic Microwave Background (CMB) anisotropy power spectrum observed by the Cosmic Background Imager (CBI). We probe the angular structure of the excess in the CBI deep fields and investigate whether it could be due to the scattering of CMB photons by hot electrons within clusters, the Sunyaev-Zeldovich (SZ) effect. We estimate the density fluctuation parameters for amplitude, sigma_8, and shape, Gamma, from CMB primary anisotropy data and other cosmological data. We use the results of two separate hydrodynamical codes for Lambda-CDM cosmologies, consistent with the allowed sigma_8 and Gamma values, to quantify the expected contribution from the SZ effect to the bandpowers of the CBI experiment and pass simulated SZ effect maps through our CBI analysis pipeline. The result is very sensitive to the value of sigma_8, and is roughly consistent with the observed power if sigma_8 ~ 1. We conclude that the CBI anomaly could be a result of the SZ effect for the class of Lambda-CDM concordance models if sigma_8 is in the upper range of values allowed by current CMB and Large Scale Structure (LSS) data.Comment: Accepted by The Astrophysical Journal; 17 pages including 12 color figures. v2 matches accepted version. Additional information at http://www.astro.caltech.edu/~tjp/CBI