Related papers: Effective conductance method for the primordial re…
We have combined the detailed He I recombination model of Smits with the collisional transitions of Sawey & Berrington in order to produce new accurate helium emissivities that include the effects of collisional excitation from both the 2…
Component separation is the process of extracting one or more emission sources in astrophysical maps. It is therefore crucial to develop models that can accurately clean the cosmic microwave background (CMB) in current and future…
Hyperspectral neutron computed tomography enables 3D non-destructive imaging of the spectral characteristics of materials. In traditional hyperspectral reconstruction, the data for each neutron wavelength bin is reconstructed separately.…
Astrophysical models of primordial star formation require rate constants for three-body recombination as input. The current status of these rates for H2 due to collisions with H is far from satisfactory, with published rate constants…
We explore the imprint of the cosmological hydrogen recombination lines on the power spectrum of the cosmic microwave background (CMB). In particular, we focus our analysis in the three strongest lines for the Balmer, Paschen and Brackett…
Recombination of the primordial helium plasma (HeII->HeI, $z \simeq 1500 - 3000$) is considered. This process has an effect on the CMBR anisotropy and CMBR spectrum distortion. In this work an influence of neutral hydrogen on kinetics of…
Cross sections are presented for dissociative recombination and electron-impact vibrational excitation of the ArH+ molecular ion at electron energies appropriate for the interstellar environment. The R-matrix method is employed to determine…
We develop a method to reconstruct the primordial power spectrum, P(k), using both temperature and polarisation data from the joint analysis of a number of Cosmic Microwave Background (CMB) observations. The method is an extension of the…
We use extreme-ultraviolet interferometry to measure the phase of high-order harmonic generation from transiently aligned CO2 molecules. We unambiguously observe a reversal in phase of the high order harmonic emission for higher harmonic…
Component separation is the process with which emission sources in astrophysical maps are generally extracted by taking multi-frequency information into account. It is crucial to develop more reliable methods for component separation for…
The paper presents a simplified formula to determine an electron temperature, Te(He I), for planetary nebulae (PNe) using the He I 7281/6678 line flux ratio. In our previous studies of Te(He I) (Zhang et al. 2005), we used the He I line…
The presence of a primordial molecular or atomic medium can give us the possibility to investigate the first phases of the structure formation. The lines produced by resonant scattering of the CMB photons are the most important signals…
Extra radiation injection after neutrino decoupling in the early Universe contributes to the effective number of neutrino species that can be constrained by the cosmic microwave background (CMB). However, any effective neutrino number…
A model is suggested to explain the frequently observed presence of intense, narrow-band, H(alpha) emission lines in the optical spectra of reddened, early-type stars (e.g. HD 44179, IRAS 18179-1346, IRAS 20298+4011). It is proposed that…
We present trispectrum estimation methods which can be applied to general non-separable primordial and CMB trispectra. We present a general optimal estimator for the connected part of the trispectrum, for which we derive a quadratic term to…
The atomic recombination process leads to a softening of the matter equation of state as reflected by a reduced generalized adiabatic index, with accompanying heat release. We study the effects of this recombination softening and reheating…
The blackbody spectrum of CMB was created in the blackbody photosphere at redshifts z>2x10^6. At these early times, the Universe was dense and hot enough that complete thermal equilibrium between baryonic matter (electrons and ions) and…
Spectral distortions of the Cosmic Microwave Background (CMB) offer the possibility of probing processes which occurred during the evolution of our Universe going back up to Z$\simeq 10^7$. Unfortunately all the attempts so far carried out…
Spectral distortions of the cosmic microwave background (CMB) have been recognized as an important future probe of the early Universe. Existing theoretical studies primarily focused on describing the evolution and creation of average…
The computational cost of quantum algorithms for physics and chemistry is closely linked to the spectrum of the Hamiltonian, a property that manifests in the necessary rescaling of its eigenvalues. The typical approach of using the 1-norm…