[show abstract][hide abstract] ABSTRACT: Planck's all-sky surveys at 30-857 GHz provide an unprecedented opportunity to follow the radio spectra of a large sample of extragalactic sources to frequencies 2-20 times higher than allowed by past, large-area, ground-based surveys. We combine the results of the Planck Early Release Compact Source Catalog (ERCSC) with quasi-simultaneous ground-based observations as well as archival data at frequencies below or overlapping Planck frequency bands, to validate the astrometry and photometry of the ERCSC radio sources and study the spectral features shown in this new frequency window opened by Planck. The ERCSC source positions and flux density scales are found to be consistent with the ground-based observations. We present and discuss the spectral energy distributions of a sample of "extreme" radio sources, to illustrate the richness of the ERCSC for the study of extragalactic radio sources. Variability is found to play a role in the unusual spectral features of some of these sources.
[show abstract][hide abstract] ABSTRACT: This paper presents an all-sky model of dust emission from the Planck 857,
545 and 353 GHz, and IRAS 100 micron data. Using a modified black-body fit to
the data we present all-sky maps of the dust optical depth, temperature, and
spectral index over the 353-3000 GHz range. This model is a tight
representation of the data at 5 arcmin. It shows variations of the order of 30
% compared with the widely-used model of Finkbeiner, Davis, and Schlegel. The
Planck data allow us to estimate the dust temperature uniformly over the whole
sky, providing an improved estimate of the dust optical depth compared to
previous all-sky dust model, especially in high-contrast molecular regions. An
increase of the dust opacity at 353 GHz, tau_353/N_H, from the diffuse to the
denser interstellar medium (ISM) is reported. It is associated with a decrease
in the observed dust temperature, T_obs, that could be due at least in part to
the increased dust opacity. We also report an excess of dust emission at HI
column densities lower than 10^20 cm^-2 that could be the signature of dust in
the warm ionized medium. In the diffuse ISM at high Galactic latitude, we
report an anti-correlation between tau_353/N_H and T_obs while the dust
specific luminosity, i.e., the total dust emission integrated over frequency
(the radiance) per hydrogen atom, stays about constant. The implication is that
in the diffuse high-latitude ISM tau_353 is not as reliable a tracer of dust
column density as we conclude it is in molecular clouds where the correlation
of tau_353 with dust extinction estimated using colour excess measurements on
stars is strong. To estimate Galactic E(B-V) in extragalactic fields at high
latitude we develop a new method based on the thermal dust radiance, instead of
the dust optical depth, calibrated to E(B-V) using reddening measurements of
quasars deduced from Sloan Digital Sky Survey data.
[show abstract][hide abstract] ABSTRACT: We present the XMM-Newton follow-up for validation of Planck cluster candidates. Twenty-five candidates have been observed to date using snapshot (~10 ksec) exposures: ten as part of a pilot programme to sample a low range of signal-to-noise ratios (45 candidates. The sensitivity and spatial resolution of XMM-Newton allows unambiguous discrimination between clusters and false candidates. A total of 21 candidates are confirmed as extended X-ray sources. Seventeen are single clusters, the majority of which are found to have highly irregular and disturbed morphologies. The remaining four sources are multiple systems, including the unexpected discovery of a supercluster at z=0.45. For most of the sources we are able to derive a redshift estimate from the X-ray Fe K line (albeit of variable quality). The new clusters span the redshift range 0.09 <~ z <~ 0.54 with a median redshift of z ~ 0.37. A first estimate is made of their X-ray properties including the characteristic size, which is used to improve the SZ Compton parameter estimate. The validation programme has helped to optimise the Planck candidate selection process. It has also provided a preview of the X-ray properties of these newly-discovered clusters, allowing comparison to their SZ properties, and to the X-ray and SZ properties of known clusters observed in the Planck survey. Our results suggest that Planck may have started to reveal a non-negligible population of massive dynamically perturbed objects that is under-represented in X-ray surveys. However, despite their particular properties, these new clusters appear to follow the Ysz-Yx relation established for X-ray selected objects.
[show abstract][hide abstract] ABSTRACT: We present the first all-sky sample of galaxy clusters detected blindly by the Planck satellite through the Sunyaev-Zeldovich (SZ) effect from its six highest frequencies. This Early SZ (ESZ) sample of 189 candidates comprises high signal-to-noise clusters, from 6 to 29. Its high reliability (purity above 95%) is further insured by an extensive validation process based on Planck-internal quality assessments and external cross-identification and follow-up observations. Planck provides the first measured SZ signal for about 80% of the 169 ESZ known clusters. Planck further releases 30 new cluster candidates among which 20 are within the ESZ signal-to-noise selection criterion. Eleven of these 20 ESZ candidates are confirmed using XMM-Newton snapshot observations as new clusters, most of them with disturbed morphologies and low luminosities. The ESZ clusters are mostly at moderate redshifts (86% with z below 0.3) and span over a decade in mass, up to the rarest and most massive clusters with masses above 10^15 Msol.
[show abstract][hide abstract] ABSTRACT: The performance of the Planck instruments in space is enabled by their low operating temperatures, 20K for LFI and 0.1K for HFI, achieved through a combination of passive radiative cooling and three active mechanical coolers. Active coolers were chosen to minimize straylight on the detectors and to maximize lifetime. The scientific requirement for very broad frequency led to two detector technologies with widely different temperature and cooling needs. This made use of a helium cryostat, as used by previous cryogenic space missions (IRAS, COBE, ISO, SPITZER, AKARI), infeasible. Radiative cooling is provided by three V-groove radiators and a large telescope baffle. The active coolers are a hydrogen sorption cooler (<20K), a 4He Joule-Thomson cooler (4.7K), and a 3He-4He dilution cooler (1.4K and 0.1K). The flight system was at ambient temperature at launch and cooled in space to operating conditions. The bolometer plate of the High Frequency Instrument reached 93mK on 3 July 2009, 50 days after launch. The solar panel always faces the Sun, shadowing the rest of Planck, and operates at a mean temperature of 384K. At the other end of the spacecraft, the telescope baffle operates at 42.3K and the telescope primary mirror operates at 35.9K. The temperatures of key parts of the instruments are stabilized by both active and passive methods. Temperature fluctuations are driven by changes in the distance from the Sun, sorption cooler cycling and fluctuations in gas-liquid flow, and fluctuations in cosmic ray flux on the dilution and bolometer plates. These fluctuations do not compromise the science data.
[show abstract][hide abstract] ABSTRACT: Planck's all sky surveys at 30-857 GHz provide an unprecedented opportunity to follow the radio spectra of a large sample of extragalactic sources to frequencies 2-20 times higher than allowed by past, large area, ground-based surveys. We combine the results of the Planck Early Release Compact Source Catalog (ERCSC) with quasi-simultaneous ground-based observations, as well as archival data, at frequencies below or overlapping Planck frequency bands, to validate the astrometry and photometry of the ERCSC radio sources and study the spectral features shown in this new frequency window opened by Planck. The ERCSC source positions and flux density scales are found to be consistent with the ground-based observations. We present and discuss the spectral energy distributions (SEDs) of a sample of "extreme" radio sources to illustrate the richness of the ERCSC for the study of extragalactic radio sources. Variability is found to play a role in the unusual spectral features of some of these sources.
[show abstract][hide abstract] ABSTRACT: We present new measurements of CIB anisotropies using Planck. Combining HFI
data with IRAS, the angular auto- and cross frequency power spectrum is
measured from 143 to 3000 GHz, and the auto-bispectrum from 217 to 545 GHz. The
total areas used to compute the CIB power spectrum and bispectrum are about
2240 and 4400 deg^2, respectively. After careful removal of the contaminants,
and a complete study of systematics, the CIB power spectrum and bispectrum are
measured with unprecedented signal to noise ratio from angular multipoles
ell~150 to 2500, and ell~130 to 1100, respectively. Two approaches are
developed for modelling CIB power spectrum anisotropies. The first approach
takes advantage of the unique measurements by Planck at large angular scales,
and models only the linear part of the power spectrum, with a mean bias of dark
matter halos hosting dusty galaxies at a given redshift weighted by their
contribution to the emissivities. The second approach is based on a model that
associates star-forming galaxies with dark matter halos and their subhalos,
using a parametrized relation between the dust-processed infrared luminosity
and (sub-)halo mass. The two approaches simultaneously fit all auto- and cross-
power spectra very well. We find that the star formation history is well
constrained up to z~2. However, at higher redshift, the accuracy of the star
formation history measurement is strongly degraded by the uncertainty in the
spectral energy distribution of CIB galaxies. We also find that CIB galaxies
have warmer temperatures as redshift increases. The CIB bispectrum is steeper
than that expected from the power spectrum, although well fitted by a power
law; this gives some information about the contribution of massive halos to the
[show abstract][hide abstract] ABSTRACT: This paper presents the detection, interpretation and removal of the signal resulting from interactions of high energy particles with the Planck High Frequency Instrument (HFI). These interactions fall into two categories, heating the 0.1K bolometer plate and glitches in each detector time stream. Glitch shapes are not simple single pole exponential decays and fall into three families. The glitch shape for each family has been characterized empirically in flight data and removed from the detector time streams. The spectrum of the count rate per unit energy is computed for each family and a correspondence to where on the detector the particle hit is made. Most of the detected glitches are from galactic protons incident on the Si die frame supporting the micromachinced bolometric detectors. At HFI, the particle flux is � 5 cm2 s1 and is dominated by protons incident on the spacecraft with an energy >39MeV, leading to a rate of typically one event per second and per detector. Di�erent categories of glitches have di�erent signature in timestreams. Two of the glitch types have a low amplitude component that decays over nearly 1 second. This component produces an excess noise if not properly removed from the time ordered data. We have used a glitch detection and subtraction method based on the joint fit of population templates. The application of this novel glitch removal method removes excess noise from glitches. Using realistic simulations, we find this method does not introduce signal bias.
[show abstract][hide abstract] ABSTRACT: Based on CMB maps from the 2013 Planck Mission data release, this paper presents the detection of the ISW effect, i.e., the correlation between the CMB and large-scale evolving gravitational potentials. The significance of detection ranges from 2 to 4 sigma, depending on which method is used. We investigate three separate approaches, which cover essentially all previous studies, as well as breaking new ground. (i) Correlation of the CMB with the Planck reconstructed gravitational lensing potential (for the first time). This detection is made using the lensing-induced bispectrum; the correlation between lensing and the ISW effect has a significance close to 2.5 sigma. (ii) Cross-correlation with tracers of LSS, yielding around 3 sigma significance, based on a combination of radio (NVSS) and optical (SDSS) data. (iii) Aperture photometry on stacked CMB fields at the locations of known large-scale structures, which yields a 4 sigma signal when using a previously explored catalogue, but shows strong discrepancies in amplitude and scale compared to expectations. Recent catalogues give more moderate results, ranging from negligible to 2.5 sigma at most, but with a more consistent scale and amplitude, the latter being still slightly above what is expected from numerical simulations within LCMD. Where they can be compared, these measurements are compatible with previous work using data from WMAP, which had already mapped these scales to the limits of cosmic variance. Planck's broader frequency coverage confirms that the signal is achromatic, bolstering the case for ISW detection. As a final step we use tracers of large-scale structure to filter the CMB data, presenting maps of the ISW temperature perturbation. These results provide complementary and independent evidence for the existence of a dark energy component that governs the current accelerated expansion of the Universe.