We investigate the merging rates of compact binaries in galaxies and the related detection rate of gravitational wave (GW) events with AdvLIGO/Virgo and with the Einstein Telescope. To this purpose, ...we rely on three basic ingredients: (i) the redshift-dependent galaxy statistics provided by the latest determination of the star formation rate functions from UV+far-IR/(sub)millimeter/radio data; (ii) star formation and chemical enrichment histories for individual galaxies, modeled on the basis of observations; and (iii) compact remnant mass distribution and prescriptions for merging of compact binaries from stellar evolution simulations. We present results for the intrinsic birth rate of compact remnants, the merging rates of compact binaries, GW detection rates, and GW counts, attempting to differentiate the outcomes among black hole-black hole, neutron star-neutron star, and black hole-neutron star mergers and to estimate their occurrence in disk and spheroidal host galaxies. We compare our approach with the one based on cosmic star formation rate density and cosmic metallicity, exploited by many literature studies; the merging rates from the two approaches are in agreement within the overall astrophysical uncertainties. We also investigate the effects of galaxy-scale strong gravitational lensing of GW in enhancing the rate of detectable events toward high redshift. Finally, we discuss the contribution of undetected GW emission from compact binary mergers to the stochastic background.
We quantify the contamination from polarized diffuse Galactic synchrotron and thermal dust emissions to the B modes of the cosmic microwave background (CMB) anisotropies on the degree angular scale, ...using data from the Planck and Wilkinson Microwave Anisotropy Probe (WMAP) satellites. In this way we estimate the amplitude and frequency of the foreground minimum for each analyzed region. We detect both dust and synchrotron signal on degree angular scales and at a 3s confidence level in 28 regions. Here the minimum of the foreground emission is found at frequencies between 60 and 100 GHz with an amplitude expressed in terms of the equivalent tensor-to-scalar ratio, rFG,min, between ~0.06 and ~1. Our results indicate that, with the current sensitivity at low frequency, it is not possible to exclude the presence of synchrotron contamination to CMB cosmological B modes at the level requested to measure a gravitational waves signal with r = 0.01 at frequency 100 GHz anywhere.
We combine the latest data sets obtained with different surveys to study the frequency dependence of polarized emission coming from extragalactic radio sources (ERS). We consider data over a very ...wide frequency range starting from 1.4 GHz up to 217 GHz. This range is particularly interesting since it overlaps the frequencies of the current and forthcoming cosmic microwave background (CMB) experiments. Current data suggest that at high radio frequencies ( ≥ 20 GHz) the fractional polarization of ERS does not depend on the total flux density. Conversely, recent data sets indicate a moderate increase of polarization fraction as a function of frequency, physically motivated by the fact that Faraday depolarization is expected to be less relevant at high radio frequencies. We compute ERS number counts using updated models based on recent data, and we forecast the contribution of unresolved ERS in CMB polarization spectra. Given the expected sensitivities and the observational patch sizes of forthcoming CMB experiments, about ∼200 (up to ∼2000) polarized ERS are expected to be detected. Finally, we assess that polarized ERS can contaminate the cosmological B-mode polarization if the tensor-to-scalar ratio is <0.05 and they have to be robustly controlled to de-lens CMB B-modes at the arcminute angular scales.
Abstract
We present a model for simulating carbon monoxide (CO) rotational line emission in molecular clouds, taking account of their 3D spatial distribution in galaxies with different geometrical ...properties. The model implemented is based on recent results in the literature and has been designed for performing Monte Carlo (MC) simulations of this emission. We compare the simulations produced with this model and calibrate them, both on the map and the power spectrum levels, using the second release of data from the Planck satellite for the Galactic plane, where the signal-to-noise ratio is highest. We use the calibrated model to extrapolate the CO power spectrum at low Galactic latitudes where no high sensitivity observations are available yet. We then forecast the level of unresolved polarized emission from CO molecular clouds which could contaminate the power spectrum of cosmic microwave background polarization B modes away from the Galactic plane. Assuming realistic levels of the polarization fraction, we show that the level of contamination is equivalent to a cosmological signal with r ≲ 0.02. The MC MOlecular Line Emission (mcmole3d) python package, which implements this model, is being made publicly available.
ABSTRACT We present an improved and extended analysis of the cross-correlation between the map of the cosmic microwave background (CMB) lensing potential derived from the Planck mission data and the ...high-redshift galaxies detected by the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) in the photometric redshift range . We compare the results based on the 2013 and 2015 Planck datasets, and investigate the impact of different selections of the H-ATLAS galaxy samples. Significant improvements over our previous analysis have been achieved thanks to the higher signal-to-noise ratio of the new CMB lensing map recently released by the Planck collaboration. The effective galaxy bias parameter, b, for the full galaxy sample, derived from a joint analysis of the cross-power spectrum and of the galaxy auto-power spectrum is found to be . Furthermore, a first tomographic analysis of the cross-correlation signal is implemented by splitting the galaxy sample into two redshift intervals: and . A statistically significant signal was found for both bins, indicating a substantial increase with redshift of the bias parameter: for the lower and for the higher redshift bin. Consistent with our previous analysis, we find that the amplitude of the cross-correlation signal is a factor of higher than expected from the standard ΛCDM model for the assumed redshift distribution. The robustness of our results against possible systematic effects has been extensively discussed, although the tension is mitigated by passing from 4 to 3 .
In this work, the design of precision voltage and current sources for a new quench detection system for the protection of superconducting power cables is proposed. The key strength of the design ...resides in its low complexity, which allows to obtain a low-cost and reliable hardware implementation for the new detector. The voltage source output goes from 200 mV to 800 mV, while the current source output is adjustable between 50 mA and 1 A. Experimental results from the sources characterization campaign validate the design: 24-hours time stability is demonstrated to be about 20 ppm for the voltage source, and below 1000 ppm for the minimum current of 50 mA of the current source. Furthermore, the measured superposed noise is less than −80 dBV and the Mean Time Between Failures (MTBF) is estimated to be about 20 million hours for both sources. The improvement of the quench detector features is also demonstrated through further experiments. The obtained results demonstrate the effectiveness of the proposed detection mechanism and pave the way for further research on large-scale use of high-temperature superconducting cables.
We present a quantitative analysis of the astrophysical and cosmological information that can be extracted from the many important wide-area, shallow surveys that will be carried out in the next few ...years. Our calculations combine the predictions of the physical model by Granato et al. for the formation and evolution of spheroidal galaxies with up-to-date phenomenological models for the evolution of starburst and normal late-type galaxies and of radio sources. We compute the expected number counts and the redshift distributions of these source populations separately and then focus on protospheroidal galaxies. For the latter objects, we predict the counts and redshift distributions of strongly lensed sources at 250, 350, 500 and 850 μm, the angular correlation function of sources detected in the surveys considered, and the angular power spectra due to clustering of sources below the detection limit in Herschel and Planck surveys. An optimal survey for selecting strongly lensed protospheroidal galaxies is described, and it is shown how they can be easily distinguished from the other source populations. We also discuss the detectability of the imprints of the one-halo and two-halo regimes on angular correlation functions and clustering power spectra, as well as the constraints on cosmological parameters that can be obtained from the determinations of these quantities. The novel data relevant to derive the first submillimetre estimates of the local luminosity functions of starburst and late-type galaxies, and the constraints on the properties of rare source populations, such as blazars, are also briefly described.
ABSTRACT We extend a general maximum likelihood foreground estimation for cosmic microwave background (CMB) polarization data to include estimation of instrumental systematic effects. We focus on two ...particular effects: frequency band measurement uncertainty and instrumentally induced frequency dependent polarization rotation. We assess the bias induced on the estimation of the B-mode polarization signal by these two systematic effects in the presence of instrumental noise and uncertainties in the polarization and spectral index of Galactic dust. Degeneracies between uncertainties in the band and polarization angle calibration measurements and in the dust spectral index and polarization increase the uncertainty in the extracted CMB B-mode power, and may give rise to a biased estimate. We provide a quantitative assessment of the potential bias and increased uncertainty in an example experimental configuration. For example, we find that with 10% polarized dust, a tensor to scalar ratio of r = 0.05, and the instrumental configuration of the E and B experiment balloon payload, the estimated CMB B-mode power spectrum is recovered without bias when the frequency band measurement has 5% uncertainty or less, and the polarization angle calibration has an uncertainty of up to 4°.
We study the concentration parameters, their mass dependence and redshift evolution, of dark-matter halos in different dark-energy cosmologies with constant and time-variable equation of state, and ...compare them with “standard” ΛCDM and OCDM models. We find that previously proposed algorithms for predicting halo concentrations can be well adapted to dark-energy models. When centred on the analytically expected values, halo concentrations show a log-normal distribution with a uniform standard deviation of ~0.2. The dependence of averaged halo concentrations on mass and redshift permits a simple fit of the form $(1+z)\,c=c_0\,(M/M_0)^\alpha$, with $\alpha\approx-0.1$ throughout. We find that the cluster concentration depends on the dark energy equation of state at the cluster formation redshift zcoll through the linear growth factor $D_+(z_{\rm coll})$. As a simple correction accounting for dark-energy cosmologies, we propose scaling c0 from ΛCDM with the ratio of linear growth factors, $c_0\rightarrow c_0\,D_+(z_{\rm coll})/D_{+,~\Lambda{\rm CDM}}(z_{\rm coll})$.
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