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The scattering of cosmic microwave background (CMB) photons off the free-electron gas in galaxies and clusters leaves detectable imprints on high resolution CMB maps: the thermal and kinematic Sunyaev-Zel'dovich effects (tSZ and kSZ respectively). We use combined microwave maps from the Atacama Cosmology Telescope DR5 and Planck in combination with the CMASS (mean redshift ⟨z

We present the temperature and polarization angular power spectra measured by the Atacama Cosmology Telescope Polarimeter (ACTPol). We analyze night-time data collected during 2013-14 using two detector arrays at 149 GHz, from 548 deg2 of sky on the celestial equator. We use these spectra, and the spectra measured with the MBAC camera on ACT from 2008-10, in combination with planck and wmap data to estimate cosmological parameters from the temperature, polarization, and temperature-polarization cross-correlations. We find the new ACTPol data to be consistent with the ΛCDM model. The ACTPol temperature-polarization cross-spectrum now provides stronger constraints on multiple parameters than the ACTPol temperature spectrum, including the baryon density, the acoustic peak angular scale, and the derived Hubble constant. The new ACTPol data provide information on damping tail parameters. The joint uncertainty on the number of neutrino species and the primordial helium fraction is reduced by 20% when adding ACTPol to Planck temperature data alone.

We present a new method for modeling inhomogeneous cosmic reionization on large scales. Utilizing high-resolution radiation-hydrodynamic simulations with 20483 dark matter particles, 20483 gas cells, and 17 billion adaptive rays in a L = 100 Mpc h–1 box, we show that the density and reionization redshift fields are highly correlated on large scales (≳ 1 Mpc h–1). This correlation can be statistically represented by a scale-dependent linear bias. We construct a parametric function for the bias, which is then used to filter any large-scale density field to derive the corresponding spatially varying reionization redshift field. The parametric model has three free parameters that can be reduced to one free parameter when we fit the two bias parameters to simulation results. We can differentiate degenerate combinations of the bias parameters by combining results for the global ionization histories and correlation length between ionized regions. Unlike previous semi-analytic models, the evolution of the reionization redshift field in our model is directly compared cell by cell against simulations and performs well in all tests. Our model maps the high-resolution, intermediate-volume radiation-hydrodynamic simulations onto lower-resolution, larger-volume N-body simulations (≳ 2 Gpc h–1) in order to make mock observations and theoretical predictions. [ABSTRACT FROM AUTHOR]

We present new predictions for cosmic microwave background (CMB) temperature (on small angular scales) and polarization (on large angular scales) anisotropies induced during the epoch of reionization (EoR). Using a novel method calibrated from radiation-hydrodynamic simulations, we model the EoR in large volumes (L ≳ 2 Gpc h–1). We find that the EoR contribution to the kinetic Sunyaev-Zel'dovich power spectrum (patchy kSZ) ranges between ∼0.6-2.8 μK2 at ℓ = 3000 for the explored parameter space. For each model, the patchy kSZ power spectrum is calculated from three large 15° × 15° maps for better numerical convergence. Decreasing the size of these maps biases the overall patchy kSZ power to higher values. We find that the amplitude of the patchy kSZ power spectrum at ℓ = 3000 follows simple scalings of and for the mean redshift () and duration (Δz) of reionization. Using the constraints on from the Wilkinson Microwave Anisotropy Probe seven year results and the lower limit on Δz from EDGES, we find a lower limit of ∼0.4 μK2 at ℓ = 3000. Planck will infer the mean redshift from the Thomson optical depth imprinted in the low-ℓ polarization power spectrum. Future measurements of the high-ℓ CMB power spectrum from the Atacama Cosmology Telescope and South Pole Telescope should detect the patchy kSZ signal if the cross correlation between the thermal SZ effect and the cosmic infrared background is constrained. We show that the combination of temperature and polarization measurements constrains both and Δz. The patchy kSZ maps, power spectra templates, and the polarization power spectra will be publicly available. [ABSTRACT FROM AUTHOR]

We investigate the effect of patchy reionization on the cosmic microwave background (CMB) temperature. An anisotropic optical depth alters the TT power spectrum on small scales l > 2000. We make use of the correlation between the matter density and the reionization redshift fields to construct full sky maps of . Patchy reionization transfers CMB power from large scales to small scales, resulting in a non-zero cross correlation between large and small angular scales. We show that the patchy τ correlator is sensitive to small root mean square (rms) values τrms ∼ 0.003 seen in our maps. We include frequency-independent secondaries such as CMB lensing and kinetic Sunyaev-Zel'dovich (kSZ) terms, and show that patchy τ may still be detected at high significance. Reionization models that predict different values of τrms may be distinguished even for the same mean value 〈 τ〉 . It is more difficult to detect patchy τ in the presence of larger secondaries such as the thermal Sunyaev-Zel'dovich, radio background, and the cosmic infrared background. In this case, we show that patchy τ may be detected if these frequency-dependent secondaries are minimized to ≲ 5 μK (rms) by means of a multi-frequency analysis. We show that the patchy τ correlator provides information that is complementary to what may be obtained from the polarization and the kSZ power spectra. [ABSTRACT FROM AUTHOR]

We present predictions for the 21 cm brightness temperature power spectrum during the Epoch of Reionization (EoR). We discuss the implications of the “light cone” effect, which incorporates evolution of the neutral hydrogen fraction and 21 cm brightness temperature along the line of sight. Using a novel method calibrated against radiation-hydrodynamic simulations, we model the neutral hydrogen density field and 21 cm signal in large volumes (L = 2 Gpc h–1). The inclusion of the light cone effect leads to a relative decrease of about 50% in the 21 cm power spectrum on all scales. We also find that the effect is more prominent at the midpoint of reionization and later. The light cone effect can also introduce an anisotropy along the line of sight. By decomposing the 3D power spectrum into components perpendicular to and along the line of sight, we find that in our fiducial reionization model, there is no significant anisotropy. However, parallel modes can contribute up to 40% more power for shorter reionization scenarios. The scales on which the light cone effect is relevant are comparable to scales where one measures the baryon acoustic oscillation. We argue that due to its large comoving scale and introduction of anisotropy, the light cone effect is important when considering redshift space distortions and future application to the Alcock-Paczyński test for the determination of cosmological parameters. [ABSTRACT FROM AUTHOR]

The redox reactions of NH 3 and CH 3 NH 2 with N 2 O 4 (NTO) have been studied by ab initio molecular orbital (MO) calculations at the UCCSD(T)∥UB3LYP/6-311+G(3df,2p) level of theory. These reactions are related to the well-known NTO-hydrazine(s) propellant systems. On the basis of the predicted potential energy surfaces, the mechanisms for these reactions were found to be similar to the hydrolysis of NTO and the hypergolic initiation reaction of the NTO-N 2 H 4 mixture, primarily controlled by the conversion of NTO to ONONO 2 via very loose transition states (with NH 3 and CH 3 NH 2 as spectators in the collision complexes) followed by the rapid attack of ONONO 2 at the spectating molecules producing HNO 3 and RNO (R = NH 2 and CH 3 NH). The predicted mechanism for the NH 3 reaction compares closely with its isoelectronic process NTO + H 2 O; similarly, the mechanism for the NTO + CH 3 NH 2 reaction also compares closely with its isoelectronic NTO + NH 2 NH 2 reaction. The kinetics for the formation of the final products, HNO 3 + RNO (R = NH 2 , OH, CH 3 NH, and N 2 H 3 ), were found to be weakly pressure-dependent at low temperatures and affected by the strengths of H-NH 2 and H-OH but not in the RNH 2 case. We have also compared the predicted rate constant for the oxidation of NH 3 by N 2 O 4 with that for the analogous NH 3 + N 2 O 5 recently reported by Sarkar and Bandyopadhyay [ J. Phys. Chem. A. 2020 , 124 , 3564-3572] under troposphere conditions. The rate of the latter reaction was estimated to be 2 orders of magnitude slower than that of the N 2 O 4 reaction under troposphere conditions.

Using high-resolution microwave sky maps made by the Atacama Cosmology Telescope, we for the first time present strong evidence for motions of galaxy clusters and groups via microwave background temperature distortions due to the kinematic Sunyaev-Zel'dovich effect. Galaxy clusters are identified by their constituent luminous galaxies observed by the Baryon Oscillation Spectroscopic Survey, part of the Sloan Digital Sky Survey III. We measure the mean pairwise momentum of clusters, with a probability of the signal being due to random errors of 0.002, and the signal is consistent with the growth of cosmic structure in the standard model of cosmology.

We use the Ly-alpha forest power spectrum measured by the Sloan Digital Sky Survey and high-resolution spectroscopy observations in combination with cosmic microwave background and galaxy clustering constraints to place limits on a sterile neutrino as a dark matter candidate in the warm dark matter scenario. Such a neutrino would be created in the early Universe through mixing with an active neutrino and would suppress structure on scales smaller than its free-streaming scale. We ran a series of high-resolution hydrodynamic simulations with varying neutrino masses to describe the effect of a sterile neutrino on the Ly-alpha forest power spectrum. We find that the mass limit is m(s) >13 keV at 95% C.L. (9 keV at 99.9%), which is above the upper limit allowed by x-ray constraints, excluding this candidate from being all of the dark matter in this model.