H 2 pure-rotational emission lines are detected from warm (100-1500 K) molecular gas in 17/55 (31% of) radio galaxies at redshift z < 0.22 observed with the Spitzer IR Spectrograph. The summed H 2 0-038 -2 × 10 42 erg s −1 , yielding warm H 2 masses up to 2 × 10 10 M . These radio galaxies, of both FR radio morphological types, help to firmly establish the new class of radio-selected molecular hydrogen emission galaxies (radio MOHEGs). MOHEGs have extremely large H 2 to 7.7 μm polycyclic aromatic hydrocarbon (PAH) emission ratios: L(H 2 )/L(PAH7.7) = 0.04-4, up to a factor 300 greater than the median value for normal star-forming galaxies. In spite of large H 2 masses, MOHEGs appear to be inefficient at forming stars, perhaps because the molecular gas is kinematically unsettled and turbulent. Low-luminosity mid-IR continuum emission together with low-ionization emission line spectra indicates low-luminosity active galactic nuclei (AGNs) in all but three radio MOHEGs. The AGN X-ray emission measured with Chandra is not luminous enough to power the H 2 emission from MOHEGs. Nearly all radio MOHEGs belong to clusters or close pairs, including four cool-core clusters (Perseus, Hydra, A2052, and A2199). We suggest that the H 2 in radio MOHEGs is delivered in galaxy collisions or cooling flows, then heated by radio-jet feedback in the form of kinetic energy dissipation by shocks or cosmic rays.

We present spectral energy distributions (SEDs) of 69 QSOs at z > 5, covering a rest frame wavelength range of 0.1 µm to ∼80 µm, and centered on new Spitzer and Herschel observations. The detection rate of the QSOs with Spitzer is very high (97% at λ rest 4 µm), but drops towards the Herschel bands with 30% detected in PACS (rest frame mid-infrared) and 15% additionally in the SPIRE (rest frame far-infrared; FIR). We perform multi-component SED fits for Herschel-detected objects and confirm that to match the observed SEDs, a clumpy torus model needs to be complemented by a hot (∼1300K) component and, in cases with prominent FIR emission, also by a cold (∼50K) component. In the FIR detected cases the luminosity of the cold component is on the order of 10 13 L which is likely heated by star formation. From the SED fits we also determine that the AGN dust-to-accretion disk luminosity ratio declines with UV/optical luminosity. Emission from hot (∼1300K) dust is common in our sample, showing that nuclear dust is ubiquitous in luminous QSOs out to redshift 6. However, about 15% of the objects appear under-luminous in the near infrared compared to their optical emission and seem to be deficient in (but not devoid of) hot dust. Within our full sample, the QSOs detected with Herschel are found at the high luminosity end in L UV/opt and L NIR and show low equivalent widths (EWs) in Hα and in Lyα. In the distribution of Hα EWs, as determined from the Spitzer photometry, the high-redshift QSOs show little difference to low redshift AGN.

We present Herschel far-infrared (FIR) photometry of eleven quasars at redshift z > 5 that have previously been detected at 1.2 mm. We perform full spectral energy distribution (SED) fits over the wavelength range λ rest ∼ 0.1-400 µm for those objects with good Herschel detections. These fits reveal the need for an additional far-infrared (FIR) component besides the emission from a dusty AGNpowered torus. This additional FIR component has temperatures of T FIR ∼ 40-60 K with luminosities of L 8−1000µm ∼ 10 13 L (accounting for 25-60% of the bolometric FIR luminosity). If the FIR dust emission is due to star formation it would suggest star formation rates in excess of 1000 solar masses per year. We show that at long wavelengths (λ rest 50 µm) the contribution of the AGN-powered torus emission is negligible. This explains how previous FIR studies of high-redshift quasars that relied on single component fits to (ground-based) observations at λ obs 350 µm reached T FIR and L FIR values similar to our complete SED fits. Stacking the Herschel data of four individually undetected sources reveals a significant average signal in the PACS bands but not in SPIRE. The average SED of sources with individual Herschel detections shows a striking surplus in near-and mid-infrared emission when compared to common AGN templates. The comparison between two average SEDs (sources with and without individual Herschel detections) matched in the UV/optical indicates that for these objects the strength of the MIR emission may correlate with the strength of the FIR emission.

We complete the census of nuclear X-ray activity in 100 early type Virgo galaxies observed by the Chandra X-ray Telescope as part of the AMUSE-Virgo survey, down to a (3σ) limiting luminosity of 3.7 × 10 38 erg s −1 over 0.5-7 keV. The stellar mass distribution of the targeted sample, which is mostly composed of formally 'inactive' galaxies, peaks below 10 10 M , a regime where the very existence of nuclear super-massive black holes (SMBHs) is debated. Out of 100 objects, 32 show a nuclear X-ray source, including 6 hybrid nuclei which also host a massive nuclear cluster as visible from archival Hubble Space Telescope images. After carefully accounting for contamination from nuclear low-mass X-ray binaries based on the shape and normalization of their X-ray luminosity function, we conclude that between 24 − 34% of the galaxies in our sample host a X-ray active SMBH (at the 95% C.L.). This sets a firm lower limit to the black hole occupation fraction in nearby bulges within a cluster environment. The differential logarithmic X-ray luminosity function of active SMBHs scales with the X-ray luminosity as L X −0.4±0.1 up to 10 42 erg s −1 . At face value, the active fraction -down to our luminosity limit-is found to increase with host stellar mass. However, taking into account selection effects, we find that the average Eddington-scaled X-ray luminosity scales with black hole mass as M BH −0.62 +0.13 −0.12 , with an intrinsic scatter of 0.46 +0.08 −0.06 dex. This finding can be interpreted as observational evidence for 'down-sizing' of black hole accretion in local early types, that is, low mass black holes shine relatively closer to their Eddington limit than higher mass objects. As a consequence, the fraction of active galaxies, defined as those above a fixed X-ray Eddington ratio, decreases with increasing black hole mass.

Quasars are thought to be powered by supermassive black holes accreting surrounding gas. Central to this picture is a putative accretion disk which is believed to be the source of the majority of the radiative output. It is well known, however, that the most extensively studied disk model-an optically thick disk which is heated locally by the dissipation of gravitational binding energy-is apparently contradicted by observations in a few major respects. In particular, the model predicts a specific blue spectral shape asymptotically from the visible to the near-infrared, but this is not generally seen in the visible wavelength region where the disk spectrum is observable. A crucial difficulty has been that, towards the infrared, the disk spectrum starts to be hidden under strong, hot dust emission from much larger but hitherto unresolved scales, and thus has essentially been impossible to observe. Here we report observations of polarized light interior to the dust-emitting region that enable us to uncover this near-infrared disk spectrum in several quasars. The revealed spectra show that the near-infrared disk spectrum is indeed as blue as predicted. This indicates that, at least for the outer near-infrared-emitting radii, the standard picture of the locally heated disk is approximately correct.