The apodized-pupil Lyot coronagraph is one of the most advanced starlight cancellation concepts studied intensively in the past few years. Extreme adaptive optics instruments built for present-day 8m class telescopes will operate with such coronagraph for imagery and spectroscopy of faint stellar companions. Following the development of an early demonstrator in the context of the VLT-SPHERE project (~2012), we manufactured and tested a second APLC prototype in microdots designed for extremely large telescopes. This study has been conducted in the context of the EPICS instrument project for the European-ELT (~2018), where a proof of concept is required at this stage. Our prototype was specifically designed for the European-ELT pupil, taking its large central obscuration ratio (30%) into account. Near-IR laboratory results are compared with simulations. We demonstrate good agreement with theory. A peak attenuation of 295 was achieved, and contrasts of 10^-5 and 10^-6 were reached at 7 and 12 lambda/D, respectively. We show that the APLC is able to maintain these contrasts with a central obscuration ratio of the telescope in the range 15% to 30%, and we report that these performances can be achieved in a wide wavelength bandpass (BW = 24%). In addition, we report improvement to the accuracy of the control of the local transmission of the manufactured microdot apodizer to that of the previous prototype. The local profile error is found to be less than 2%. The maturity and reproducibility of the APLC made with microdots is demonstrated. The apodized pupil Lyot coronagraph is confirmed to be a pertinent candidate for high-contrast imaging with ELTs.

High signal-to-noise (S/N) observations of the QSO PKS 0405-123 (zem = 0.572) with the Cosmic Origins Spectrograph from 1134 to 1796 A with a resolution of 17 km s-1 are used to study the multi-phase partial Lyman limit system (LLS) at z = 0.16716 which has previously been studied using relatively low S/N spectra from STIS and FUSE. The LLS and an associated H I-free broad O VI absorber likely originate in the circumgalactic gas associated with a pair of galaxies at z = 0.1688 and 0.1670 with impact parameters of 116 h70-1 and 99 h70-1. The broad and symmetric O VI absorption is detected in the z = 0.16716 restframe with v = -278 +/- 3 km s-1, log N(O VI) = 13.90 +/- 0.03 and b = 52 +/- 2 km s-1. This absorber is not detected in H I or other species with the possible exception of N V . The broad, symmetric O VI profile and absence of corresponding H I absorption indicates that the circumgalactic gas in which the collisionally ionized O VI arises is hot (log T ~ 5.8-6.2). The absorber may represent a rare but important new class of low z IGM absorbers. The LLS has strong asymmetrical O VI absorption with log N(O VI) = 14.72 +/- 0.02 spanning a velocity range from -200 to +100 km s-1. The high and low ions in the LLS have properties resembling those found for Galactic highly ionized HVCs where the O VI is likely produced in the conductive and turbulent interfaces between cool and hot gas.

Aims: Today, large ground-based instruments, like VISIR on the VLT, providing diffraction-limited (about 0.3 arcsec) images in the mid-infrared where strong PAH features appear enable us to see the flaring structure of the disks around Herbig Ae stars. Although great progress has been made in modelling the disk with radiative transfer models able to reproduce the spectral energy distribution (SED) of Herbig Ae stars, the constraints brought by images have not been yet fully exploited. Here, we are interested in checking if these new observational imaging constraints can be accounted for by predictions based on existing models of passive centrally irradiated hydrostatic disks made to fit the SEDs of the Herbig Ae stars. Methods: The images taken by VISIR in the 8.6 and 11.3 microns aromatic features reveal a large flaring disk around HD97048 inclined to the line of sight. In order to analyse the spatial distribution of these data, we use a disk model which includes the most up to date understanding of disk structure and physics around Herbig Ae stars with grains in thermal equilibrium in addition to transiently-heated PAHs. Results: We compare the observed spatial distribution of the PAH emission feature and the adjacent continuum emission with predictions based on existing full disk models. Both SED and spatial distribution are in very good agreement with the model predictions for common disk parameters. Conclusions: We take the general agreement between observations and predictions as a strong support for the physical pictures underlying our flared disk model.

Aims: Today, large ground-based instruments, like VISIR on the VLT, providing diffraction-limited (about 0.3 arcsec) images in the mid-infrared where strong PAH features appear enable us to see the flaring structure of the disks around Herbig Ae stars. Although great progress has been made in modelling the disk with radiative transfer models able to reproduce the spectral energy distribution (SED) of Herbig Ae stars, the constraints brought by images have not been yet fully exploited. Here, we are interested in checking if these new observational imaging constraints can be accounted for by predictions based on existing models of passive centrally irradiated hydrostatic disks made to fit the SEDs of the Herbig Ae stars. Methods: The images taken by VISIR in the 8.6 and 11.3 microns aromatic features reveal a large flaring disk around HD97048 inclined to the line of sight. In order to analyse the spatial distribution of these data, we use a disk model which includes the most up to date understanding of disk structure and physics around Herbig Ae stars with grains in thermal equilibrium in addition to transiently-heated PAHs. Results: We compare the observed spatial distribution of the PAH emission feature and the adjacent continuum emission with predictions based on existing full disk models. Both SED and spatial distribution are in very good agreement with the model predictions for common disk parameters. Conclusions: We take the general agreement between observations and predictions as a strong support for the physical pictures underlying our flared disk model.

Aims: Today, large ground-based instruments, like VISIR on the VLT, providing diffraction-limited (about 0.3 arcsec) images in the mid-infrared where strong PAH features appear enable us to see the flaring structure of the disks around Herbig Ae stars. Although great progress has been made in modelling the disk with radiative transfer models able to reproduce the spectral energy distribution (SED) of Herbig Ae stars, the constraints brought by images have not been yet fully exploited. Here, we are interested in checking if these new observational imaging constraints can be accounted for by predictions based on existing models of passive centrally irradiated hydrostatic disks made to fit the SEDs of the Herbig Ae stars. Methods: The images taken by VISIR in the 8.6 and 11.3 microns aromatic features reveal a large flaring disk around HD97048 inclined to the line of sight. In order to analyse the spatial distribution of these data, we use a disk model which includes the most up to date understanding of disk structure and physics around Herbig Ae stars with grains in thermal equilibrium in addition to transiently-heated PAHs. Results: We compare the observed spatial distribution of the PAH emission feature and the adjacent continuum emission with predictions based on existing full disk models. Both SED and spatial distribution are in very good agreement with the model predictions for common disk parameters. Conclusions: We take the general agreement between observations and predictions as a strong support for the physical pictures underlying our flared disk model.