Herschel Survey of the Palomar-Green QSOs at Low Redshift

We investigate the global cold dust properties of 85 nearby (z < 0.5) QSOs, chosen from the Palomar-Green sample of optically luminous quasars. We determine their infrared spectral energy distributions and estimate their rest-frame luminosities by combining Herschel data from 70 to 500 microns with near-infrared and mid-infrared measurements from the Two Micron All Sky Survey (2MASS) and the Wide-Field Infrared Survey Explorer (WISE). In most sources the far-infrared (FIR) emission can be attributed to thermally heated dust. Single temperature modified black body fits to the FIR photometry give an average dust temperature for the sample of 33~K, with a standard deviation of 8~K, and an average dust mass of 7E6 Solar Masses with a standard deviation of 9E6 Solar Masses. Estimates of star-formation that are based on the FIR continuum emission correlate with those based on the 11.3 microns PAH feature, however, the star-formation rates estimated from the FIR continuum are higher than those estimated from the 11.3 microns PAH emission. We attribute this result to a variety of factors including the possible destruction of the PAHs and that, in some sources, a fraction of the FIR originates from dust heated by the active galactic nucleus and by old stars.Comment: accepted for publication in ApJ

Star Clusters in M51: Connection between Molecular Gas, Stars and Dust

We have mapped key molecular line probes (¹²CO, ¹³CO, C¹⁸O, HCN, HCO⁺) in two distinct regions in the spiral arms of the Whirlpool galaxy, M51. Line Velocity Gradient (LVG) analysis performed at a linear resolution of 135–210 pc (2.9–4.5 arcsec) suggests physical conditions in the Giant Molecular Cloud complexes (GMCs) of M51 very similar to those in the Milky Way: cold (T_(kin) ∼ 15 K) clouds with moderate H₂ density (n(H₂) < 10^(2.7) cm⁻³. We find indications for a galactocentric trend, with higher kinetic temperature for smaller radii. The data show little evidence for cloud heating by the massive star formation at our resolution of 135 pc. Our new deep ∼ 2 arcsec radio continuum images at 3.6 and 6 cm reveal the presence of some highly dust-obscured young star-forming regions within the molecular spiral arms

Overview of JET results

High density and high confinement operation in ELMy H-mode is confirmed at or above the normalized parameters foreseen for the ITER operating point (H98(y,2) 3c 1, n/nGW 3c 1, \u3b2N > 1.8 at q95 3c 3). The scaling of the ELMy H-mode with \u3b2N could be more favourable than that predicted by the IPB98(y,2) scaling. In ELMy H-mode, ion cyclotron current drive (ICCD) control of large sawteeth stabilized by fast particle has been demonstrated and the underlying neo-classical tearing modes (NTMs) and sawtooth physics is being refined. At high-density, Type I ELMy H-modes show trends that would lead to marginally acceptable ELMs on ITER. Type II ELM regime has been produced, though under very restrictive conditions. Type III ELMy operation with radiation fractions up to 95% has been demonstrated by seeding of N2 in H-modes and could extrapolate to Q = 10 ITER operation, albeit at high current (17 MA). The mitigation of Type I ELMs, nevertheless, remains a challenge. Considerable progress has been obtained in internal transport barrier (ITB) plasmas, with operation at central densities close to the Greenwald density or/and low toroidal rotation or/and high triangularity. Demonstrations of full current drive and successful simultaneous real time control of safety factor and temperature profiles have been achieved in ITB plasmas. Physics of resistive wall modes (RWMs) has been compared with theory, showing favourable scaling for ITER. High \u3b2N 3c 2.8 operation of hybrid modes (also called improved H-modes) has been obtained with dominant neutral beam heating. Hybrid modes with dominant ion cyclotron resonance heating (ICRH) have also been achieved. Trace tritium experiments yielded valuable information on particle transport in H-mode, ITB and hybrid regimes. In Type I ELMy plasmas, successful tests of the conjugate-T ICRH scheme have been achieved as well as lower hybrid coupling at ITER-relevant 10\u201311 cm distances. Reduced D and T fuel retention has been observed, which could relate to operation with vertical targets in the divertor and/or lower (ITER-like) vessel temperature. It is confirmed that erosion occurs predominantly on the main chamber surfaces, with possible benefits for T retention in ITER, although consequences for the metallic first wall lifetime need to be assessed. Disruption and ELM studies indicate that transient power deposition could be less constraining than expected for the ITER divertor, but more challenging for the metallic first wall. Alpha particle tomography and direct observation of alpha particle slowing down have been made possible by \u3b3 -spectroscopy. Measurements of Alfve \u301n cascades have been improved by a new interferometric technique. Promising tests of ITER relevant neutron counting detectors have been conducted