109 research outputs found
On the ISW-cluster cross-correlation in future surveys
We investigate the cosmological information contained in the
cross-correlation between the Integrated Sachs-Wolfe (ISW) of the Cosmic
Microwave Background (CMB) anisotropy pattern and galaxy clusters from future
wide surveys. Future surveys will provide cluster catalogues with a number of
objects comparable with galaxy catalogues currently used for the detection of
the ISW signal by cross-correlation with the CMB anisotropy pattern. By
computing the angular power spectra of clusters and the corresponding
cross-correlation with CMB, we perform a signal-to-noise ratio (SNR) analysis
for the ISW detection as expected from the eROSITA and the Euclid space
missions. We discuss the dependence of the SNR of the ISW-cluster
cross-correlation on the specifications of the catalogues and on the reference
cosmology. We forecast that the SNRs for ISW-cluster cross-correlation are
alightly smaller compared to those which can be obtained from future galaxy
surveys but the signal is expected to be detected at high significance, i.e.
more than . We also forecast the joint constraints on parameters
of model extensions of the concordance CDM cosmology by combining CMB
and the ISW-cluster cross-correlation.Comment: 12 pages, 10 figures. Matches version accepted in MNRA
4KRL adhesive thermal cycle facility
This document will describe the cryo facility designed for sample thermal cycling
Planck/LFI 30/44 GHz Sky Load Implementation
Purpose of this note is to characterise the behaviour of the calibrator named ‘RCA SKY
LOAD’(RCA-SL); the specific feature to investigate is the equivalent temperature seen by the feed.
To do this, it needs both a radio-frequency and a thermal analysis, being the specific emissivity and
the physical temperature of the load strictly tied. Only a combined unitary analysis can allow to
maximise the radiometric emissivity and the thermal stability, taking into account radiometric
fluctuations of the different parts arising from fluctuations of the reference temperature source
Attività di ‘packaging’ degli LNA all’interno del carrier, studiato per funzionare a temperature criogeniche
Il presente documento si inserisce nell’ambito delle attività svolte finalizzate allo studio e alla realizzazione di un prototipo di amplificatore criogenico a basso rumore in banda W, basato su tecnologia MMIC mHEMT.
Il cuore del lavoro è l’attività di ‘packaging’ degli LNA all’interno del modulo (carrier), studiato per funzionare a temperature criogeniche.
Tale attività ha evidenziato potenziali criticità che si desidera, attraverso questa nota tecnica, approfondire
The 4KRL cryo facility
Purpose of the Planck-LFI 4KRL is to provide a stable reference signal to the LFI radiometers. It is fully
described in RD 1.
Purpose of the instrument described in this note is to provide a test facility for the 4KRL unit.
Purpose of this document is to describe the general characteristics and performance of this facility
Square Kilometre Array and cosmic microwave background spectral distortions
The Square Kilometre Array (SKA) is a new technology (large array) radio-telescope that, owing to its extremely high sensitivity and resolution, will allow to investigate different cosmological and astrophysical topics. In this work, we discuss the possible contribution of the SKA in combination with future cosmic microwave background experiments in probing various types of dissipation processes relevant at different cosmic epochs
4KRL dummy FM design and verification
Purpose of this document is to describe the 4KRL dummy FM unit and the verification activities
performed by the 4KRL development team before delivering it to the HFI
PLANCK\LFI 4K Reference Load Test Plan
The purpose of this document is to describe the tests to be performed on the QM, FM, and FS
4KRL uni
A Refined Calibration Procedure of Two-Channel Sun Photometers to Measure Atmospheric Precipitable Water at Various Antarctic Sites
Abstract
Two-channel sun photometers can be easily employed at Antarctic sites, where harsh environmental conditions prevail, to carry out measurements of precipitable water W. In the very dry air conditions observed in the Antarctic atmosphere, water vapor does not produce strong absorption features along the sun path. Therefore, these instruments need to be calibrated using analytical forms different from the square root regime, which can be determined by simulating the output voltages measured at Antarctic sites, for the spectral near-IR curves of extraterrestrial solar irradiance, instrumental responsivity parameters, and atmospheric transmittance, relative to various measurement periods. For this purpose, average models of the Antarctic atmosphere from the ground level up to the 30-km altitude were considered for different solar zenith angles and relative humidity conditions. The ratios between the output voltages simulated in the band and window channels were plotted as a function of total water vapor content Cw, for each site and each period, to define the best-fit calibration curves, which were subsequently normalized to the field measurements to take into account the aging effects on the filter transmission characteristics. Each of the five calibration curves was found to present a slope coefficient decreasing gradually with Cw from values higher than 0.8 to about 0.6. Using these curves, measurements of W were obtained, which differ appreciably at both sea level and high-altitude sites from those given by the square root calibration curves, avoiding large overestimation errors of 10%–40% at the high-altitude sites and underestimation errors of 5%–15% at the sea level site
Preliminary evaluation of the impact of temperature fluctuations in the HFI 4Kstage on LFI
In this technical note we provide a preliminary analysis of the effect of temperature fluctuations at the level
of the HFI 4K stage on the scientific performances of the Planck-LFI instrument. The stability of this stage is
of crucial importance for the LFI, as it impact directly the stability of the measured signal through its
reference load. The availability of the first simulations of the 4K temperature stability from the HFI team has
prompted a quick assessment of the expected effect, which is found to be large enough to require the
application of software removal algorithms to maintain the residual effect in the final maps within the
required levels. Clearly it is of crucial importance the availability in a short time of measurements from the HFI 4K cooler in order to be able to perform robust estimates of the final expected systematic effect
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