Abstract. We present the first fully and uniformly sampled, spatially complete H  survey of the entire Magellanic System with high velocity resolution (∆v = 1.0 km s −1 ), performed with the Parkes Telescope . Approximately 24 percent of the southern sky was covered by this survey on a ≈5 grid with an angular resolution of HPBW = 14. 1. A fully automated data-reduction scheme was developed for this survey to handle the large number of H  spectra (1.5 × 10 6 ). The individual Hanning smoothed and polarization averaged spectra have an rms brightness temperature noise of σ = 0.12 K. The final data-cubes have an rms noise of σ rms ≈ 0.05 K and an effective angular resolution of ≈16 . In this paper we describe the survey parameters, the datareduction and the general distribution of the H  gas. , if all H  gas is at the same distance of 55 kpc. Approximately two thirds of this H  gas is located close to the Magellanic Clouds (Magellanic Bridge and Interface Region), and 25% of the H  gas is associated with the Magellanic Stream. The Leading Arm has a four times lower H  mass than the Magellanic Stream, corresponding to 6% of the total H  mass of the gaseous features.We have analyzed the velocity field of the Magellanic Clouds and their neighborhood introducing a LMC-standard-of-rest frame. The H  in the Magellanic Bridge shows low velocities relative to the Magellanic Clouds suggesting an almost parallel motion, while the gas in the Interface Region has significantly higher relative velocities indicating that this gas is leaving the Magellanic Bridge building up a new section of the Magellanic Stream. The Leading Arm is connected to the Magellanic Bridge close to an extended arm of the LMC. The clouds in the Magellanic Stream and the Leading Arm show significant differences, both in the column density distribution and in the shapes of the line profiles. The H  gas in the Magellanic Stream is more smoothly distributed than the gas in the Leading Arm. These morphological differences can be explained if the Leading Arm is at considerably lower z-heights and embedded in a higher pressure ambient medium.

The European Space Agency's Planck satellite, dedicated to studying the early Universe and its subsequent evolution, was launched 14 May 2009 and has been scanning the microwave and submillimetre sky continuously since 12 August 2009. In March 2013, ESA and the Planck Collaboration released the initial cosmology products based on the first 15.5 months of Planck data, along with a set of scientific and technical papers and a web-based explanatory supplement. This paper gives an overview of the mission and its performance, the processing, analysis, and characteristics of the data, the scientific results, and the science data products and papers in the release. The science products include maps of the cosmic microwave background (CMB) and diffuse extragalactic foregrounds, a catalogue of compact Galactic and extragalactic sources, and a list of sources detected through the Sunyaev-Zeldovich effect. The likelihood code used to assess cosmological models against the Planck data and a lensing likelihood are described. Scientific results include robust support for the standard six-parameter ΛCDM model of cosmology and improved measurements of its parameters, including a highly significant deviation from scale invariance of the primordial power spectrum. The Planck values for these parameters and others derived from them are significantly different from those previously determined. Several large-scale anomalies in the temperature distribution of the CMB, first detected by WMAP, are confirmed with higher confidence. Planck sets new limits on the number and mass of neutrinos, and has measured gravitational lensing of CMB anisotropies at greater than 25σ. Planck finds no evidence for non-Gaussianity in the CMB. Planck's results agree well with results from the measurements of baryon acoustic oscillations. Planck finds a lower Hubble constant than found in some more local measures. Some tension is also present between the amplitude of matter fluctuations (σ 8 ) derived from CMB data and that derived from Sunyaev-Zeldovich data. The Planck and WMAP power spectra are offset from each other by an average level of about 2% around the first acoustic peak. Analysis of Planck polarization data is not yet mature, therefore polarization results are not released, although the robust detection of E-mode polarization around CMB hot and cold spots is shown graphically.

Context. Gas within a galaxy is forced to establish pressure balance against gravitational forces. The shape of an unperturbed gaseous disk can be used to constrain dark matter models.Aims. We derive the 3D H i volume density distribution for the Milky Way out to a galactocentric radius of 40 kpc and a height of 20 kpc to constrain the Galactic mass distribution. Methods. We used the Leiden/Argentine/Bonn all sky 21-cm line survey. The transformation from brightness temperatures to densities depends on the rotation curve. We explored several models, reflecting different dark matter distributions. Each of these models was set up to solve the combined Poisson-Boltzmann equation in a self-consistent way and optimized to reproduce the observed flaring. Results. Besides a massive extended halo of M ∼ 1.8 × 1012 M , we find a self-gravitating dark matter disk with M = 2 to 3 × 10 11 M , including a dark matter ring at 13 < R < 18.5 kpc with M = 2.2 to 2.8 × 10 10 M . The existence of the ring was previously postulated from EGRET data and coincides with a giant stellar structure that surrounds the Galaxy. The resulting Milky Way rotation curve is flat up to R ∼ 27 kpc and slowly decreases outwards. The H i gas layer is strongly flaring. The HWHM scale height is 60 pc at R = 4 kpc and increases to ∼2700 pc at R = 40 kpc. Spiral arms cause a noticeable imprint on the gravitational field, at least out to R = 30 kpc. Conclusions. Our mass model supports previous proposals that the giant stellar ring structure is due to a merging dwarf galaxy. The fact that the majority of the dark matter in the Milky Way for R < ∼ 40 kpc can be successfully modeled by a self-gravitating isothermal disk raises the question of whether this massive disk may have been caused by similar merger events in the past. The substructure in the Galactic dark matter disk suggests a dissipative nature for the dark matter disk.

We investigate data from the Galactic Effelsberg-Bonn Hi Survey (EBHIS), supplemented with data from the third release of the Galactic All Sky Survey (GASS III) observed at Parkes. We explore the all sky distribution of the local Galactic Hi gas with |v LSR | < 25 km s −1 on angular scales of 11 to 16 . Unsharp masking (USM) is applied to extract small scale features. We find cold filaments that are aligned with polarized dust emission and conclude that the cold neutral medium (CNM) is mostly organized in sheets that are, because of projection effects, observed as filaments. These filaments are associated with dust ridges, aligned with the magnetic field measured on the structures by Planck at 353 GHz. The CNM above latitudes |b| > 20 • is described by a log-normal distribution, with a median Doppler temperature T D = 223 K, derived from observed line widths that include turbulent contributions. The median neutral hydrogen (HI) column density is N HI 10 19.1 cm −2 . These CNM structures are embedded within a warm neutral medium (WNM) with N HI 10 20 cm −2 . Assuming an average distance of 100 pc, we derive for the CNM sheets a thickness of 0.3 pc. Adopting a magnetic field strength of B tot = (6.0 ± 1.8)µG, proposed by Heiles & Troland 2005, and assuming that the CNM filaments are confined by magnetic pressure, we estimate a thickness of 0.09 pc. Correspondingly the median volume density is in the range 14 n 47 cm −3 .