Constraining gravity at large scales with the 2MASS Photometric Redshift catalogue and Planck lensing

We present a new measurement of structure growth at $z \simeq 0.08$ obtained by correlating the cosmic microwave background (CMB) lensing potential map from the \textit{Planck} satellite with the angular distribution of the 2MASS Photometric Redshift galaxies. After testing for, and finding no evidence for systematic effects, we calculate the angular auto- and cross-power spectra. We combine these spectra to estimate the amplitude of structure growth using the bias-independent $D_G$ estimator introduced by Giannantonio et al. 2016. We find that the relative amplitude of $D_G$ with respect to the predictions based on \textit{Planck} cosmology is $A_D(z=0.08) = 1.00 \pm 0.21$, fully consistent with the expectations for the standard cosmological model. Considering statistical errors only, we forecast that a joint analysis between an LSST-like photometric galaxy sample and lensing maps from upcoming ground-based CMB surveys like the Simons Observatory and CMB-S4 can yield sub-percent constraints on the growth history and differentiate between different models of cosmic acceleration.Comment: 14 pages, 8 figures, 1 table, updated to match published version on Ap

Green polities: urban environmental performance and government popularity

Ascertaining whether local election results are driven by incumbents’ performance while in office or mechanically reflect constituencies’ ideological affiliation and macroeconomic conditions is crucial for evaluating the alleged accountability-enhancing property of decentralization. Based on a unique score of urban environmental performance and the results of all elections held in the major Italian cities over a decade, we investigate the role of local (fiscal and environmental) versus national issues in municipal elections. While the empirical evidence points to a strong ideological attachment and a somewhat weaker fiscal conservatism, it reveals that media reported environmental ranking has a considerable impact on the popularity of city governments.Local elections, vote function, environmental performance, property tax

Cosmic Microwave Background and Large Scale Structure: Cross-Correlation as seen from Herschel and Planck satellites

As well as providing us with a snapshot of the Universe at the time of recombination, the cosmic microwave backround (CMB) radiation carries a wealth of information about the later evolution of the Universe through the so-called CMB secondary anisotropies that originates from the interaction between CMB photons and the Large Scale Structure (LSS). This thesis deals with two of these effects: the CMB lensing and the kinematic Sunyaev-Zel'dovich (kSZ). In particular, we present the first cross-correlation analysis between the CMB lensing maps reconstructed by Planck team and the angular position of galaxies from the Herschel H-ATLAS survey, the highest redshift sample exploited for cross-correlation analysis to date. By splitting the galaxy catalog in two redshift bins, we also attempt a tomographic analysis of the signal and reconstruct the galaxy bias evolution over cosmic time. On the other hand, the kSZ effect measures the integrated free electron momentum up to high redshift, thus being sensitive to the cosmic flows and the reionization history. Here we study its capabilities in constraining theories of modified gravity

Imprints of gravitational lensing in the Planck CMB data at the location of WISExSCOS galaxies

We detect weak gravitational lensing of the cosmic microwave background (CMB) at the location of the WISExSCOS (WxS) galaxies using the publicly available Planck lensing convergence map. By stacking the lensing convergence map at the position of 12.4 million galaxies in the redshift range $0.1\le z \le 0.345$, we find the average mass of the galaxies to be M$_{200_{\rm crit}}$ = 6.25 $\pm$ 0.6 $\times 10^{12}\ M_{\odot}$. The null hypothesis of no-lensing is rejected at a significance of $17\sigma$. We split the galaxy sample into three redshift slices each containing $\sim$4.1 million objects and obtain lensing masses in each slice of 4.18 $\pm$ 0.8, 6.93 $\pm$ 0.9, and 18.84 $\pm$ 1.2 \times\ 10^{12}\ \mbox{M}_{\odot}. Our results suggest a redshift evolution of the galaxy sample masses but this apparent increase might be due to the preferential selection of intrinsically luminous sources at high redshifts. The recovered mass of the stacked sample is reduced by 28% when we remove the galaxies in the vicinity of galaxy clusters with mass M$_{200_{\rm crit}}$ = 2 \times 10^{14}\ \mbox{M}_{\odot}. We forecast that upcoming CMB surveys can achieve 5% galaxy mass constraints over sets of 12.4 million galaxies with M$_{200_{\rm crit}}$ = $1 \times 10^{12}\ M_{\odot}$ at $z=1$.Comment: 7 pages, 2 figures, 2 tables: updates: correlations between z-bins included: accepted for publication in PR

CMB spectral distortions revisited: a new take on μ\mu distortions and primordial non-Gaussianities from FIRAS data

Deviations from the blackbody spectral energy distribution of the CMB are a precise probe of physical processes active both in the early universe (such as those connected to particle decays and inflation) and at later times (e.g. reionization and astrophysical emissions). Limited progress has been made in the characterization of these spectral distortions after the pioneering measurements of the FIRAS instrument on the COBE satellite in the early 1990s, which mainly targeted the measurement of their average amplitude across the sky. Since at present no follow-up mission is scheduled to update the FIRAS measurement, in this work we re-analyze the FIRAS data and produce a map of $\mu$-type spectral distortion across the sky. We provide an updated constraint on the $\mu$ distortion monopole $|\langle\mu\rangle|<47\times 10^{-6}$ at 95\% confidence level that sharpens the previous FIRAS estimate by a factor of $\sim 2$. We also constrain primordial non-Gaussianities of curvature perturbations on scales $10\lesssim k\lesssim 5\times 10^4$ through the cross-correlation of $\mu$ distortion anisotropies with CMB temperature and, for the first time, the full set of polarization anisotropies from the Planck satellite. We obtain upper limits on $f_{\rm NL}\lesssim 3.6 \times 10^6$ and on its running $n_{\rm NL}\lesssim 1.4$ that are limited by the FIRAS sensitivity but robust against galactic and extragalactic foreground contaminations. We revisit previous similar analyses based on data of the Planck satellite and show that, despite their significantly lower noise, they yield similar or worse results to ours once all the instrumental and astrophysical uncertainties are properly accounted for. Our work is the first to self-consistently analyze data from a spectrometer and demonstrate the power of such instrument to carry out this kind of science case with reduced systematic uncertainties.Comment: Comments welcome, data will be made available upon acceptanc

Green polities: urban environmental performance and government popularity

Ascertaining whether local election results are driven by incumbents’performance while in office or mechanically reflect constituencies’ ideological affiliation and macroeconomic conditions is crucial for evaluating the alleged accountability-enhancing property of decentralization. Based on a unique score of urban environmental performance and the results of all elections held in the major Italian cities over a decade, we investigate the role of local (fiscal and environmental) versus national issues in municipal elections. While the empirical evidence points to a strong ideological attachment and a somewhat weaker fiscal conservatism, it reveals that media reported environmental ranking has a considerable impact on the popularity of city governments

What does (or does not) determine persistent corporate high-growth

Theoretical and empirical studies of industry dynamics have extensively focused on the process of growth. Theory predicts that production efficiency, profitability and financial status are central channels through which some firms can survive, grow and eventually achieve outstanding growth performance. Is the same conceptual framework a convincing explanation to account for persistent corporate high growth? Exploiting panels of Italian, Spanish, and French firms we find no evidence that this is the case: companies experiencing persistent high growth are not more productive nor more profitable, and do not display peculiarly sounder financial conditions than firms that only exhibit high, but not persistent, growth performance. The finding is robust across countries, across sectors displaying different innov ation patterns, and also controlling for demographic characteristics such as age and size

Innovation strategies and firm growth

In this work, we explore the relations between sales growth and a set of innovation indicators that capture the different sources, modes and results of the innovative activity undertaken within firms. We exploit a rich panel on innovation activity of Spanish manufacturing firms, reporting detailed CIS-type information continuously over the period 2004-2011. Standard GMMpanel estimates of the average effect of innovation activities reveal significant and positive effect for internal R&D, while no effect is found for external sourcing of knowledge (external R&D, acquisition of embodied and disembodied technologies) as well as for output of innovation (process and product innovation). However, fixed-effects quantile regressions reveal that innovation activities, apart from process innovation and disembodied technical change, display a positive effect on high-growth performance. Finally, we find evidence of super-modularity of the growth function, revealing complementarities of internal R&D with product innovation, and between product and process innovation

Capse.jl: efficient and auto-differentiable CMB power spectra emulation

We present Capse.jl, a novel emulator that utilizes neural networks to predict Cosmic Microwave Background (CMB) temperature, polarization and lensing angular power spectra. The emulator computes predictions in just a few microseconds with emulation errors below 0.1 $\sigma$ for all the scales relevant for the planned CMB-S4 survey. Capse.jl can also be trained in an hour's time on a CPU. As a test case, we use Capse.jl to analyze Planck 2018 data and ACT DR4 data. We obtain the same result as standard analysis methods with a computational efficiency 3 to 6 order of magnitude higher. We take advantage of the differentiability of our emulators to use gradients-based methods, such as Pathfinder and Hamiltonian Monte Carlo (HMC), which speed up the convergence and increase sampling efficiency. Together, these features make Capse.jl a powerful tool for studying the CMB and its implications for cosmology. When using the fastest combination of our likelihoods, emulators, and analysis algorithm, we are able to perform a Planck TT + TE + EE analysis in less than a second. To ensure full reproducibility, we provide open access to the codes and data required to reproduce all the results of this work.Comment: 16 pages, 4 figure

Modelling defects in Ni-Al with EAM and DFT calculations

We present detailed comparisons between the results of embedded atom model (EAM) and density functional theory (DFT) calculations on defected Ni alloy systems. We find that the EAM interatomic potentials reproduce low-temperature structural properties in both the γ and ${{\gamma}^{\prime}}$ phases, and yield accurate atomic forces in bulk-like configurations even at temperatures as high as  ~1200 K. However, they fail to describe more complex chemical bonding, in configurations including defects such as vacancies or dislocations, for which we observe significant deviations between the EAM and DFT forces, suggesting that derived properties such as (free) energy barriers to vacancy migration and dislocation glide may also be inaccurate. Testing against full DFT calculations further reveals that these deviations have a local character, and are typically severe only up to the first or second neighbours of the defect. This suggests that a QM/MM approach can be used to accurately reproduce QM observables, fully exploiting the EAM potential efficiency in the MM zone. This approach could be easily extended to ternary systems for which developing a reliable and fully transferable EAM parameterisation would be extremely challenging e.g. Ni alloy model systems with a W or Re-containing QM zone