# ESA Science & Technology - Publication Archive

## Publication archive

## Publication archive

Published: 23 January 2015

Published: 23 January 2015

_{2-10 keV}= 2.4 × 10

^{40}erg s

^{-1}, over two orders of magnitude greater than that expected from star formation, strongly suggestive of the presence of an accreting massive black hole. While enhanced X-ray emission and hot dust can be produced in extremely low metallicity environments, J132932.41+323417.0 is not extremely metal poor (≈40% solar). With a stellar mass of 2.0 × 10

^{8}M

_{☉}, this galaxy is similar in mass to the Small Magellanic Cloud, and is one of the lowest mass galaxies with evidence for a massive nuclear black hole currently known.

Published: 18 December 2014

Published: 18 December 2014

_{200}= 4.7

^{+1.4}

_{-0.9}× 10

^{14}M

_{⊙}. We perform an analysis of the spectral energy distributions (SEDs) of 12 cluster members (5 spectroscopically confirmed) detected with ≥3σ significance in the PACS maps, all ultraluminous infrared galaxies. The individual star formation rates (SFRs) lie in the range 155-824 M

_{⊙}yr

^{-1}, with dust temperatures of 24-35 K. We measure a strikingly high amount of SF in the cluster core, SFR (<250 kpc) ≥ 1875 ± 158 M

_{⊙}yr

^{-1}, four times higher than the amount of SF in the cluster outskirts. This scenario is unprecedented in a galaxy cluster, showing for the first time a reversal of the SF-density relation at z ~ 1.6 in a massive cluster.

Published: 13 December 2014

Published: 08 December 2014

Published: 20 November 2014

*Gaia*astrometry, extending previous studies to a broader range of spectral types, distances, and magnitudes. Our assessment is based on a large representative sample of host stars from the TRILEGAL Galaxy population synthesis model, recent estimates of the exoplanet frequency distributions as a function of stellar type, and detailed simulation of the

*Gaia*observations using the updated instrument performance and scanning law. We use two approaches to estimate detectable planetary systems: one based on the signal-to-noise ratio of the astrometric signature per field crossing, easily reproducible and allowing comparisons with previous estimates, and a new and more robust metric based on orbit fitting to the simulated satellite data. With some plausible assumptions on planet occurrences, we find that some 21,000 (±6000) high-mass (~1-15

*M*) long-period planets should be discovered out to distances of ~500 pc for the nominal 5 yr mission (including at least 1000-1500 around M dwarfs out to 100 pc), rising to some 70,000 (±20, 000) for a 10 yr mission. We indicate some of the expected features of this exoplanet population, amongst them ~25-50 intermediate-period (

_{J}*P*~ 2-3 yr) transiting systems.

Published: 19 November 2014

*Context*. The first release of astrometric data from Gaia is expected in 2016. It will contain the mean stellar positions and magnitudes from the first year of observations. For more than 100 000 stars in common with the Hipparcos Catalogue it will be possible to compute very accurate proper motions due to the time difference of about 24 years between the two missions. This Hundred Thousand Proper Motions (HTPM) project is planned to be part of the first release.

*Aims*. Our aim is to investigate how early Gaia data can be optimally combined with information from the Hipparcos Catalogue in order to provide the most accurate and reliable results for HTPM.

*Methods*. The Astrometric Global Iterative Solution (AGIS) was developed to compute the astrometric core solution based on the Gaia observations and will be used for all releases of astrometric data from Gaia. We adapt AGIS to process Hipparcos data in addition to Gaia observations, and use simulations to verify and study the joint solution method.

*Results*. For the HTPM stars we predict proper motion accuracies between 14 and 134 μas yr

^{-1}, depending on stellar magnitude and amount of Gaia data available. Perspective effects will be important for a significant number of HTPM stars, and in order to treat these effects accurately we introduce a formalism called scaled model of kinematics (SMOK). We define a goodness-of-fit statistic which is sensitive to deviations from uniform space motion, caused for example by binaries with periods of 10–50 years.

*Conclusions*. HTPM will significantly improve the proper motions of the Hipparcos Catalogue well before highly accurate Gaia-only results become available.

[Remainder of abstract truncated due to character limitations]

Published: 14 November 2014

*Chandra*High Energy Transmission Grating observations obtained near the peak of its bright 2014 accretion outburst. Spectral analysis suggests the presence of a broad iron emission line centered at

*E*

_{1}≃ 6.7 keV. Fits with a disk reflection model yield an inclination angle of

*i*≃ 52° and an inner disk radius of

*R*

_{in}≃85

*GM/c²*, which is much further out than typically found for neutron star low-mass X-ray binaries. Assuming that the disk is truncated at the magnetospheric radius of the neutron star, we estimate a magnetic field strength of

*B*≃ (2-6) × 10

^{10}G. Furthermore, we identify an absorption feature near ≃ 6.85 keV that could correspond to blue-shifted Fe XXV and point to a fast disk wind with an outflow velocity of

*v*

_{out}≃ (7.5-8.2) × 10³ km s

^{-1}(≃ 0.025

*c*-0.027

*c*). If the covering fraction and filling factor are large, this wind could be energetically important and perhaps account for the fact that the companion star lost significant mass while the magnetic field of the neutron star remained strong.

Published: 03 November 2014

--- Remainder of abstract truncated due to character limitations ---

Published: 29 October 2014

^{2}, respectively. After careful removal of the contaminants (cosmic microwave background anisotropies, Galactic dust, and Sunyaev-Zeldovich emission), and a complete study of systematics, the CIB power spectrum is measured with unprecedented signal to noise ratio from angular multipoles ℓ ~ 150 to 2500. The bispectrum due to the clustering of dusty, star-forming galaxies is measured from ℓ ~ 130 to 1100, with a total signal to noise ratio of around 6, 19, and 29 at 217, 353, and 545 GHz, 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 haloes 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 haloes and their subhaloes, 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 redshifts around 2, and agrees with recent estimates of the obscured star-formation density using Spitzer and Herschel. 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.

--- Remainder of abstract truncated due to character limitations ---

Published: 29 October 2014

^{15}M

_{⊙}. Confirmation of cluster candidates through comparison with existing surveys or cluster catalogues is extensively described, as is the statistical characterization of the catalogue in terms of completeness and statistical reliability. The outputs of the validation process are provided as additional information. This gives, in particular, an ensemble of 813 cluster redshifts, and for all these Planck clusters we also include a mass estimated from a newly-proposed SZ-mass proxy. A refined measure of the SZ Compton parameter for the clusters with X-ray counter-parts is provided, as is an X-ray flux for all the Planck clusters not previously detected in X-ray surveys.

Published: 29 October 2014

Published: 29 October 2014

^{-3}, or v = 369. In addition to this signal generated by Doppler boosting of the CMB monopole, our motion also modulates and aberrates the CMB temperature fluctuations (as well as every other source of radiation at cosmological distances). This is an order 10

^{-3}effect applied to fluctuations which are already one part in roughly 10

^{5}, so it is quite small. Nevertheless, it becomes detectable with the all-sky coverage, high angular resolution, and low noise levels of the Planck satellite. Here we report a first measurement of this velocity signature using the aberration and modulation effects on the CMB temperature anisotropies, finding a component in the known dipole direction, (l,b) = (264°,48°), of 384 km s

^{-1}± 78 km s

^{-1}(stat.) ± 115 km s

^{-1}(syst.). This is a significant confirmation of the expected velocity.

Published: 29 October 2014

_{rec}), both via a direct search for matched circular patterns at the intersections and by an optimal likelihood search for specific topologies. For the latter we consider flat spaces with cubic toroidal (T3), equal-sided chimney (T2) and slab (T1) topologies, three multi-connected spaces of constant positive curvature (dodecahedral, truncated cube and octahedral) and two compact negative-curvature spaces. These searches yield no detection of the compact topology with the scale below the diameter of the last scattering surface. For most compact topologies studied the likelihood maximized over the orientation of the space relative to the observed map shows some preference for multi-connected models just larger than the diameter of the last scattering surface. Since this effect is also present in simulated realizations of isotropic maps, we interpret it as the inevitable alignment of mild anisotropic correlations with chance features in a single sky realization; such a feature can also be present, in milder form, when the likelihood is marginalized over orientations.

--- Remainder of abstract truncated due to character limitations ---

Published: 29 October 2014

_{10}at multipole ℓ = 10. This parameter has been added to the standard six parameter fit using COSMOMC with flat priors. For the Nambu-Goto string model, we have obtained a constraint on the string tension of Gμ/c

^{2}< 1.5 × 10

^{-7}and f

_{10}< 0.015 at 95% confidence that can be improved to Gμ/c

^{2}< 1.3 × 10

^{-7}and f

_{10}< 0.010 on inclusion of high-ℓ CMB data. For the Abelian-Higgs field theory model we find, Gμ

_{AH}/c

^{2}< 3.2 × 10

^{-7}and f

_{10}< 0.028. The marginalised likelihoods for f

_{10}and in the f

_{10}–Ω

_{b}h

^{2}plane are also presented. We have additionally obtained comparable constraints on f

_{10}for models with semilocal strings and global textures. In terms of the effective defect energy scale these are somewhat weaker at Gμ/c

^{2}< 1.1 × 10

^{-6}. We have made complementarity searches for the specific non-Gaussian signatures of cosmic strings, calibrating with all-sky Planck resolution CMB maps generated from networks of post-recombination strings. We have validated our non-Gaussian searches using these simulated maps in a Planck-realistic context, estimating sensitivities of up to ΔGμ/c

^{2}≈ 4 × 10

^{-7}.

--- Remainder of abstract truncated due to character limitations ---

Published: 29 October 2014

_{NL}

^{local}= 2.7 ± 5.8, f

_{NL}

^{equil}= -42 ± 75, and f

_{NL}

^{orth}= -25 ± 39 (68% CL statistical). Non-Gaussianity is detected in the data; using skew-C

_{ℓ}statistics we find a nonzero bispectrum from residual point sources, and the integrated-Sachs-Wolfe-lensing bispectrum at a level expected in the ΛCDM scenario. The results are based on comprehensive cross-validation of these estimators on Gaussian and non-Gaussian simulations, are stable across component separation techniques, pass an extensive suite of tests, and are confirmed by skew-C

_{ℓ}, wavelet bispectrum and Minkowski functional estimators. Beyond estimates of individual shape amplitudes, we present model-independent, three-dimensional reconstructions of the Planck CMB bispectrum and thus derive constraints on early-Universe scenarios that generate primordial NG, including general single-field models of inflation, excited initial states (non-Bunch-Davies vacua), and directionally-dependent vector models. We provide an initial survey of scale-dependent feature and resonance models. These results bound both general single-field and multi-field model parameter ranges, such as the speed of sound, c

_{s}≥ 0.02 (95% CL), in an effective field theory parametrization, and the curvaton decay fraction r

_{D}≥ 0.15 (95% CL). The Planck data significantly limit the viable parameter space of the ekpyrotic/cyclic scenarios.

--- Remainder of abstract truncated due to character limitations ---

Published: 29 October 2014

Published: 29 October 2014

_{s}= 0.9603 ± 0.0073, ruling out exact scale invariance at over 5σ.Planck establishes an upper bound on the tensor-to-scalar ratio of r< 0.11 (95% CL). The Planck data thus shrink the space of allowed standard inflationary models, preferring potentials with V′′< 0. Exponential potential models, the simplest hybrid inflationary models, and monomial potential models of degree n ≥ 2 do not provide a good fit to the data. Planck does not find statistically significant running of the scalar spectral index, obtaining dn

_{s}/ dlnk = − 0.0134 ± 0.0090. We verify these conclusions through a numerical analysis, which makes no slow-roll approximation, and carry out a Bayesian parameter estimation and model-selection analysis for a number of inflationary models including monomial, natural, and hilltop potentials. For each model, we present the Planck constraints on the parameters of the potential and explore several possibilities for the post-inflationary entropy generation epoch, thus obtaining nontrivial data-driven constraints. We also present a direct reconstruction of the observable range of the inflaton potential. Unless a quartic term is allowed in the potential, we find results consistent with second-order slow-roll predictions. We also investigate whether the primordial power spectrum contains any features. We find that models with a parameterized oscillatory feature improve the fit by Δχ

^{2}eff ≈ 10; however, Bayesian evidence does not prefer these models. We constrain several single-field inflation models with generalized Lagrangians by combining power spectrum data with Planck bounds on f

_{NL}.

--- Remainder of abstract truncated due to character limitations ---

Published: 29 October 2014

— 20 Items per Page