Mixed Models with n>1 and Large Scale Structure constraints

Recent data on CBR anisotropies show a Doppler peak higher than expected in CDM cosmological models, if the spectral index $n=1$. However, CDM and LCDM models with n>1 can hardly be consistent with LSS data. Mixed models, instead, whose transfer function is naturally steeper because of free--streaming in the hot component, may become consistent with data if n>1, when Omega_h is large. This is confirmed by our detailed analysis, extended both to models with a hot component whose momentum space distribution had a thermal origin (like massive neutrinos), and to models with a non--cold component arising from heavier particle decay. In this work we systematically search models which fulfill all constraints which can be implemented at the linear level. We find that a stringent linear constraint arises from fitting the extra-power parameter Gamma. Other significant constraints arise comparing the expected abundances of galaxy clusters and high-z systems with observational data. Keeping to models with Gamma \geq 0.13, a suitable part of the space parameter still allows up to \sim 30% of hot component (it is worth outlining that our stringent criteria allow only models with 0.10 \mincir Omega_h \mincir 0.16, if n \leq 1). We also outline that models with such large non--cold component would ease the solution of the so--called baryon catastrophe in galaxy clusters.Comment: 28 pages + 9 figures, uses elsart.sty, to be published in New Astronom

Planck 2015 results. XVI. Isotropy and statistics of the CMB

We test the statistical isotropy and Gaussianity of the cosmic microwave background (CMB) anisotropies using observations made by the Planck satellite. Our results are based mainly on the full Planck mission for temperature, but also include some polarization measurements. In particular, we consider the CMB anisotropy maps derived from the multi-frequency Planck data by several component-separation methods. For the temperature anisotropies, we find excellent agreement between results based on these sky maps over both a very large fraction of the sky and a broad range of angular scales, establishing that potential foreground residuals do not affect our studies. Tests of skewness, kurtosis, multi-normality, N-point functions, and Minkowski functionals indicate consistency with Gaussianity, while a power deficit at large angular scales is manifested in several ways, for example low map variance. The results of a peak statistics analysis are consistent with the expectations of a Gaussian random field. The “Cold Spot” is detected with several methods, including map kurtosis, peak statistics, and mean temperature profile. We thoroughly probe the large-scale dipolar power asymmetry, detecting it with several independent tests, and address the subject of a posteriori correction. Tests of directionality suggest the presence of angular clustering from large to small scales, but at a significance that is dependent on the details of the approach. We perform the first examination of polarization data, finding the morphology of stacked peaks to be consistent with the expectations of statistically isotropic simulations. Where they overlap, these results are consistent with the Planck 2013 analysis based on the nominal mission data and provide our most thorough view of the statistics of the CMB fluctuations to date

Extending the Planck mission in “LFI only mode” beyond January 2013

We propose to extend the Planck mission in “LFI-only” mode until 13 August 2013, which will permit the completion of an 8th full-sky survey for all LFI detectors. This extension is made possible by the predicted lifetime of the 20K sorption cooler now in operation, which far exceeds previous projections. The additional observations will lead to a significant improvement in the control of systematic effects and calibration accuracy through a set of new powerful null tests probing the 6-months, 1-year, and 2-years time scales. The current status of the Planck data analysis indicates that such improvement may be very important for a full extraction of Planck cosmological science at low multipoles, especially for polarisation. We also note that the LFI may be the last instrument delivering full-sky temperature maps in its frequency range in a very long time, adding to its legacy value

Planck LFI-only mission extension

The main reason for the extension of the Planck mission beyond the lifetime of the 0.1-K dilution cooler is to obtain further data which will improve our understanding of systematic effects. In the present report, we justify the continuation of the current scanning strategy in order to obtain a sixth survey, allowing for better sensitivity and further “jackknife” (survey difference) tests. The fifth survey is already improving the estimates of the polarisation leakage for two of the LFI horns, and this improvement will continue with the sixth survey during the extension. In addition, we confirm the “deep rings” scanning strategy to improve mapping of the beams using radio sources, specifically Jupiter and the Crab Nebula. We propose to maintain the current spin rate: no other changes are foreseen, except the possibility to increase the sampling of some house-keeping data

Microwave spectro-polarimetry of matter and radiation across space and time

From Springer Nature via Jisc Publications RouterHistory: received 2020-07-29, accepted 2021-03-02, registration 2021-03-03, pub-print 2021-06, pub-electronic 2021-07-03, online 2021-07-03Publication status: PublishedAbstract: This paper discusses the science case for a sensitive spectro-polarimetric survey of the microwave sky. Such a survey would provide a tomographic and dynamic census of the three-dimensional distribution of hot gas, velocity flows, early metals, dust, and mass distribution in the entire Hubble volume, exploit CMB temperature and polarisation anisotropies down to fundamental limits, and track energy injection and absorption into the radiation background across cosmic times by measuring spectral distortions of the CMB blackbody emission. In addition to its exceptional capability for cosmology and fundamental physics, such a survey would provide an unprecedented view of microwave emissions at sub-arcminute to few-arcminute angular resolution in hundreds of frequency channels, a data set that would be of immense legacy value for many branches of astrophysics. We propose that this survey be carried out with a large space mission featuring a broad-band polarised imager and a moderate resolution spectro-imager at the focus of a 3.5 m aperture telescope actively cooled to about 8K, complemented with absolutely-calibrated Fourier Transform Spectrometer modules observing at degree-scale angular resolution in the 10–2000 GHz frequency range. We propose two observing modes: a survey mode to map the entire sky as well as a few selected wide fields, and an observatory mode for deeper observations of regions of specific interest

Les rapports politico-strat\ue9giques franco-sovi\ue9tiques, 1930-34: une alliance manqu\ue9e?

Cet expos\ue9 est issu d'une \uab Tesi di Laurea \ubb en histoire des relations internationales soutenue en 1996 aupr\ue8s de l'universit\ue9 de Florence sous la direction du professeur Antonio Varsori, et qui a re\ue7ue la \uab dignit\ue0 di stampa \ubb. Elle fait partie d'un projet de recherche qui a vu, \ue0 partir de 1993, l'exploitation des archives des Services historiques de l'arm\ue9e de Terre, de la Marine et de l'arm\ue9e de l'Air, ainsi que celles du minist\ue8re des Affaires \ue9trang\ue8res fran\ue7ais, pour la p\ue9riode 1930-1939. Trois questions se sont entrecrois\ue9es au cours de notre recherche : - \uc9tablir, d'abord, le point de vue des militaires fran\ue7ais sur une alliance, une convention militaire, un accord g\ue9n\ue9rique ou, plus simplement, une collaboration franco-sovi\ue9tique. Quelle \ue9tait leur position aux premiers pas du rapprochement ? Cela signifie, en particulier, qu'il convient de v\ue9rifier le poids des pr\ue9jug\ue9s id\ue9ologiques sur le jugement port\ue9 par les experts militaires fran\ue7ais sur le potentiel offensif de l'URSS : les points noirs ont-ils domin\ue9 un arri\ue8re-plan pas v\ue9ritablement \ue9clairci par les milieux militaires concern\ue9s ? Ceux-ci ont-ils op\ue9r\ue9 une synth\ue8se des donn\ue9es r\ue9elles de la situation militaire sovi\ue9tique, ou plut\uf4t leur analyse \ue9tait-elle faite \ue0 travers un filtre politique ? - Gr\ue2ce au test case de la gen\ue8se, de la gestion et de l'issue des rapports militaires franco-sovi\ue9tiques, nous avons cherch\ue9 \ue0 retrouver les interconnexions de caract\ue8re institutionnel ou personnel entre le r\ue9seau militaire, charg\ue9 de l'analyse, et celui, civil, en charge de la d\ue9cision, afin d'\ue9tablir, d'une mani\ue8re n\ue9cessairement souple, le r\uf4le effectif des trois arm\ue9es au sein du processus de prise de d\ue9cision dans la France des ann\ue9es 30. - Ins\ue9rer, enfin, les rapports militaires franco-sovi\ue9tiques dans une perspective plus g\ue9n\ue9rale, celle des relations franco-russes au sein de la " maison europ\ue9enne ", de leur nouveau visage apr\ue8s la fin de l'empire des tsars en 1917, le tout analys\ue9 au lendemain de l'implosion de l\u2019" empire " sovi\ue9tique

L\u2019a\ue9ronautique militaire en Europe, entre dimension nationale, int\ue9gration europ\ue9enne et coop\ue9ration atlantique (1948-1990)

La cooperazione aeronautica europea nel settore militare fra anni '60 e anni '8