333 research outputs found
The impact of beam deconvolution on noise properties in CMB measurements: Application to Planck LFI
We present an analysis of the effects of beam deconvolution on noise
properties in CMB measurements. The analysis is built around the artDeco beam
deconvolver code. We derive a low-resolution noise covariance matrix that
describes the residual noise in deconvolution products, both in harmonic and
pixel space. The matrix models the residual correlated noise that remains in
time-ordered data after destriping, and the effect of deconvolution on it. To
validate the results, we generate noise simulations that mimic the data from
the Planck LFI instrument. A test for the full 70 GHz covariance in
multipole range yields a mean reduced of 1.0037. We
compare two destriping options, full and independent destriping, when
deconvolving subsets of available data. Full destriping leaves substantially
less residual noise, but leaves data sets intercorrelated. We derive also a
white noise covariance matrix that provides an approximation of the full noise
at high multipoles, and study the properties on high-resolution noise in pixel
space through simulations.Comment: 22 pages, 25 figure
Planck intermediate results III : The relation between galaxy cluster mass and Sunyaev-Zeldovich signal
Peer reviewe
Planck intermediate results IV : The XMM-Newton validation programme for new Planck galaxy clusters
Peer reviewe
Planck intermediate results XXIII : Galactic plane emission components derived from Planck with ancillary data
Planck data when combined with ancillary data provide a unique opportunity to separate the diffuse emission components of the inner Galaxy. The purpose of the paper is to elucidate the morphology of the various emission components in the strong star-formation region lying inside the solar radius and to clarify the relationship between the various components. The region of the Galactic plane covered is 1 = 300 degrees -> 0 degrees -> 60 degrees where star-formation is highest and the emission is strong enough to make meaningful component separation. The latitude widths in this longitude range lie between 1 and 2, which correspond to FWHM z-widths of 100-200 pc at a typical distance of 6 kpc. The four emission components studied here are synchrotron, free-free, anomalous microwave emission (AME), and thermal (vibrational) dust emission. These components are identified by constructing spectral energy distributions (SEDs) at positions along the Galactic plane using the wide frequency coverage of Planck (28.4-857 GHz) in combination with low-frequency radio data at 0.408-2.3 GHz plus WMAP data at 23-94 GHz, along with far-infrared (FIR) data from COBE-DIRBE and IRAS. The free-free component is determined from radio recombination line (RRL) data. AME is found to be comparable in brightness to the free-free emission on the Galactic plane in the frequency range 20-40 GHz with a width in latitude similar to that of the thermal dust; it comprises 45 +/- 1% of the total 28.4 GHz emission in the longitude range 1 = 300 degrees -> 0 degrees -> 60 degrees. The free-free component is the narrowest, reflecting the fact that it is produced by current star-formation as traced by the narrow distribution of OB stars. It is the dominant emission on the plane between 60 and 100 GHz. RRLs from this ionized gas are used to assess its distance, leading to a free-free z-width of FWHM approximate to 100 pc. The narrow synchrotron component has a low-frequency brightness spectral index beta(synch) approximate to -2.7 that is similar to the broad synchrotron component indicating that they are both populated by the cosmic ray electrons of the same spectral index. The width of this narrow synchrotron component is significantly larger than that of the other three components, suggesting that it is generated in an assembly of older supernova remnants that have expanded to sizes of order 150 pc in 3 x 10(5) yr; pulsars of a similar age have a similar spread in latitude. The thermal dust is identified in the SEDs with average parameters of T-dust = 20.4 +/- 0.4 K, beta(FIR) = 1.94 +/- 0.03 (>353 GHz), and beta(mm) = 1.67 +/- 0.02 (Peer reviewe
Beam-deconvolved Planck LFI maps
12 pages, 7 figuresThe Planck Collaboration made its final data release in 2018. In this paper we describe beam-deconvolution map products made from Planck LFI data using the artDeco deconvolution code to symmetrize the effective beam. The deconvolution results are auxiliary data products, available through the Planck Legacy Archive. Analysis of these deconvolved survey difference maps reveals signs of residual signal in the 30-GHz and 44-GHz frequency channels. We produce low-resolution maps and corresponding noise covariance matrices (NCVMs). The NCVMs agree reasonably well with the half-ring noise estimates except for 44\,GHz, where we observe an asymmetry between and noise spectra, possibly a sign of further unresolved systematics.Peer reviewe
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