Planck intermediate results XXV : The Andromeda galaxy as seen by Planck

The Andromeda galaxy (M 31) is one of a few galaxies that has sufficient angular size on the sky to be resolved by the Planck satellite. Planck has detected M 31 in all of its frequency bands, and has mapped out the dust emission with the High Frequency Instrument, clearly resolving multiple spiral arms and sub-features. We examine the morphology of this long-wavelength dust emission as seen by Planck, including a study of its outermost spiral arms, and investigate the dust heating mechanism across M 31. We find that dust dominating the longer wavelength emission (greater than or similar to 0.3 mm) is heated by the diffuse stellar population (as traced by 3.6 mu m emission), with the dust dominating the shorter wavelength emission heated by a mix of the old stellar population and star-forming regions (as traced by 24 mu m emission). We also fit spectral energy distributions for individual 5' pixels and quantify the dust properties across the galaxy, taking into account these different heating mechanisms, finding that there is a linear decrease in temperature with galactocentric distance for dust heated by the old stellar population, as would be expected, with temperatures ranging from around 22 K in the nucleus to 14 K outside of the 10 kpc ring. Finally, we measure the integrated spectrum of the whole galaxy, which we find to be well-fitted with a global dust temperature of (18.2 +/- 1.0) K with a spectral index of 1.62 +/- 0.11 (assuming a single modified blackbody), and a significant amount of free-free emission at intermediate frequencies of 20-60 GHz, which corresponds to a star formation rate of around 0.12 M-circle dot yr(-1). We find a 2.3 sigma detection of the presence of spinning dust emission, with a 30 GHz amplitude of 0.7 +/- 0.3 Jy, which is in line with expectations from our Galaxy.Peer reviewe

Planck intermediate results. XII: Diffuse Galactic components in the Gould Belt system

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Planck intermediate results XV : A study of anomalous microwave emission in Galactic clouds

This article has an erratum: DOI 10.1051/0004-6361/201322612ePeer reviewe

Planck 2013 results. III. LFI systematic uncertainties

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Planck 2013 results. XXVI. Background geometry and topology of the Universe

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Planck 2013 results. XXIII. Isotropy and statistics of the CMB

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Planck 2013 results. I. Overview of products and scientific results

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Planck intermediate results XXVIII. Interstellar gas and dust in the Chamaeleon clouds as seen by Fermi LAT and Planck

The nearby Chamaeleon clouds have been observed in gamma rays by the Fermi Large Area Telescope (LAT) and in thermal dust emission by Planck and IRAS. Cosmic rays and large dust grains, if smoothly mixed with gas, can jointly serve with the Hi and (CO)-C-12 radio data to (i) map the hydrogen column densities, N-H, in the different gas phases, in particular at the dark neutral medium (DNM) transition between the H I-bright and CO-bright media; (ii) constrain the CO-to-H-2 conversion factor, X-CO; and (iii) probe the dust properties per gas nucleon in each phase and map their spatial variations across the clouds. We have separated clouds at local, intermediate, and Galactic velocities in H i and (1)2CO line emission to model in parallel the gamma-ray intensity recorded between 0.4 and 100 GeV; the dust optical depth at 353 GHz, tau(353); the thermal radiance of the large grains; and an estimate of the dust extinction, A(VQ), empirically corrected for the starlight intensity. The dust and gamma-models have been coupled to account for the DNM gas. The consistent gamma-emissivity spectra recorded in the different phases confirm that the GeV-TeV cosmic rays probed by the LAT uniformly permeate all gas phases up to the (CO)-C-12 cores. The dust and cosmic rays both reveal large amounts of DNM gas, with comparable spatial distributions and twice as much mass as in the CO-bright clouds. We give constraints on the H I-DNM-CO transitions for five separate clouds. CO-dark H-2 dominates the molecular columns up to A(V) similar or equal to 0.9 and its mass often exceeds the one-third of the molecular mass expected by theory. The corrected A(VQ) extinction largely provides the best fit to the total gas traced by the gamma rays. Nevertheless, we find evidence for a marked rise in A(VQ)/N-H with increasing N-H and molecular fraction, and with decreasing dust temperature. The rise in tau(353)/N-H is even steeper. We observe variations of lesser amplitude and orderliness for the specific power of the grains, except for a coherent decline by half in the CO cores. This combined information suggests grain evolution. We provide average values for the dust properties per gas nucleon in the different phases. The gamma rays and dust radiance yield consistent X-CO estimates near 0.7 x 10(20) cm(-2) K-1 km(-1) s. The A(VQ) and tau(353) tracers yield biased values because of the large rise in grain opacity in the CO clouds. These results clarify a recurrent disparity in the gamma-versus dust calibration of X-CO, but they confirm the factor of 2 difference found between the X-CO estimates in nearby clouds and in the neighbouring spiral arms.Peer reviewe

Planck 2013 results. X. HFI energetic particle effects: characterization, removal, and simulation

We describe the detection, interpretation, and removal of the signal resulting from interactions of high energy particles with the Planck High Frequency Instrument (HFI). There are two types of interactions: heating of the 0.1 K bolometer plate; and glitches in each detector time stream. The transientresponses to detector 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 these shapes have been used to remove glitches from the detector time streams. The spectrum of the count rate per unit energy is computed for each family and a correspondence is made to the location on the detector of the particle hit. Most of the detected glitches are from Galactic protons incident on the die frame supporting the micro-machined bolometric detectors. In the Planck orbit at L2, the particle flux is around 5 cm-2 s-1 and is dominated by protons incident on the spacecraft with energy >39 MeV, at a rate of typically one event per second per detector. Different categories of glitches have different signatures in the time stream. Two of the glitch types have a low amplitude component that decays over nearly 1 s. This component produces 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 subtraction method removes excess noise from the time streams. Using realistic simulations, we find that this method does not introduce signal bias into the Planck data. Reproduced with permission from Astronomy & Astrophysics, © ESO 201

Planck intermediate results XI: The gas content of dark matter halos: the Sunyaev-Zeldovich-stellar mass relation for locally brightest galaxies

We present the scaling relation between Sunyaev-Zeldovich (SZ) signal and stellar mass for almost 260,000 locally brightest galaxies (LBGs) selected from the Sloan Digital Sky Survey (SDSS). These are predominantly the central galaxies of their dark matter halos. We calibrate the stellar-to-halo mass conversion using realistic mock catalogues based on the Millennium Simulation. Applying a multi-frequency matched filter to the Planck data for each LBG, and averaging the results in bins of stellar mass, we measure the mean SZ signal down to M 17 ~ 2 7 1011 M 99, with a clear indication of signal at even lower stellar mass. We derive the scaling relation between SZ signal and halo mass by assigning halo properties from our mock catalogues to the real LBGs and simulating the Planck observation process. This relation shows no evidence for deviation from a power law over a halo mass range extending from rich clusters down to M500 ~ 2 7 1013 M 99, and there is a clear indication of signal down to M500 ~ 4 7 1012 M 99. Planck's SZdetections in such low-mass halos imply that about a quarter of all baryons have now been seen in the form of hot halo gas, and that this gas must be less concentrated than the dark matter in such halos in order to remain consistent with X-ray observations. At the high-mass end, the measured SZ signal is 20% lower than found from observations of X-ray clusters, a difference consistent with the magnitude of Malmquist bias effects that were previously estimated for the X-ray sample