نتایج جستجو برای: planck
تعداد نتایج: 14843 فیلتر نتایج به سال:
The Langevin equation approach to the evolution of the velocity distribution for the Brownian particle might leave you uncomfortable. A more formal treatment of this type of problem is given by the Fokker-Planck equation. We can either formulate the question in terms of the evolution of a nonstationary probability distribution from a defined initial condition, or in terms of the evolution of th...
These lecture notes discuss some aspects of the Planck1 mission, whose prime objective was a very accurate measurement of the temperature anisotropies of the Cosmic Microwave Background (CMB). We announced our findings a few months ago, on March 21st , 2013. I describe some of the relevant steps we took to obtain these results, sketching the measurement process, how we processed the data to obt...
I briefly review some of the main scientific outputs expected from the upcoming Planck mission. Planck will map the CMB sky with 5’ resolution and μK sensitivity, with minimal foreground contribution and superb control on systematics. It will collect the entire information enclosed in the temperature primary anisotropy signal and will also get a good measurement of the polarized component of th...
We explore the 2013 Planck likelihood function with a high-precision multi-dimensional minimizer (Minuit). This allows a refinement of the ΛCDM best-fit solution with respect to previously-released results, and the construction of frequentist confidence intervals using profile likelihoods. The agreement with the cosmological results from the Bayesian framework is excellent, demonstrating the ro...
It is assumed that proton decays into Planck neutrinos. The energy of the Planck neutrino is equal to the Planck mass in the preferred rest frame. In the frame moving relative to the preferred rest frame the energy of the Planck neutrino reduces by the corresponding Lorentz factor. The lifetime of proton depends on the kinetic energy of proton relative to the preferred rest frame. The time requ...
This author's recent proposal of interferometric tests of Planck-scale-related properties of space-time is here revisited from a strictly phenomenological viewpoint. The results announced previously are rederived using elementary dimensional considerations. The dimensional analysis is then extended to the other two classes of experiments (observations of neutral kaons at particle accelerators a...
We investigate constraints on cosmic reionization extracted from the Planck cosmic microwave background (CMB) data. We combine the Planck CMB anisotropy data in temperature with the low-multipole polarization data to fit ΛCDM models with various parameterizations of the reionization history. We obtain a Thomson optical depth τ = 0.058±0.012 for the commonly adopted instantaneous reionization mo...
We use mock Sunyaev-Zel’dovich effect (SZE) maps to investigate how well the Planck mission might find and characterize clusters of galaxies. We discuss different combinations of frequency maps and different methods for identifying cluster candidates. The resulting catalogues are not complete even for relatively high mass thresholds, but the full sky nature of the mission ensures a large sample...
We present a list of 15 clusters of galaxies, serendipitously detected by the XMM Cluster Survey (XCS), that have a high probability of detection by the Planck satellite. Three of them already appear in the Planck Early Sunyaev–Zel’dovich (ESZ) catalogue. The estimation of the Planck detection probability assumes the flat Lambda cold dark matter ( CDM) cosmology most compatible with 7-year Wilk...
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