Astronomical instrumentation

Abstract:

We report the discovery of a faint (Lx ∼ 4 ± 1.5 × 1037 ergs s-1, 0.5-2 keV), outflowing gaseous hot interstellar medium (ISM) in NGC 3379. This represents the lowest X-ray luminosity ever measured from a hot phase of the ISM in a nearby early-type galaxy. The discovery of the hot ISM in a very deep Chandra observation was possible thanks to its unique spectral and spatial signatures, which distinguish it from the integrated stellar X-ray emission, responsible for most of the unresolved emission in the Chandra data. This hot component is found in a region of ∼800 pc in radius at the center of the galaxy and has a total mass M ∼ 3 ± 1 × 105 M⊙. Independent theoretical prediction of the characteristics of an ISM in this galaxy, based on the intrinsic properties of NGC 3379, reproduce well the observed luminosity, temperature, and radial distribution and mass of the hot gas, and indicate that the gas is in an outflowing phase, predicted by models but not observed in any system so far.

Abstract:

Presently, dedicated instrument developments at large telescopes (SPHERE for the VLT, GPI for Gemini) are about to discover and explore self-luminous giant planets by direct imaging and spectroscopy. The next generation of 30m-40m ground-based telescopes, the Extremely Large Telescopes (ELTs), have the potential to dramatically enlarge the discovery space towards older giant planets seen in reflected light and ultimately even a small number of rocky planets. EPICS is a proposed instrument for the European ELT, dedicated to the detection and characterization of expolanets by direct imaging and spectroscopy. ESO recently launched a phase-A study for EPICS with a large European consortium which - by simulations and demonstration experiments - will investigate state-of-the-art diffraction and speckle suppression techniques to deliver highest contrasts. The final result of the study in 2010 will be a conceptual design and a development plan for the instrument. Here we present first results from the phase-A study and discuss the main challenges and science capabilities of EPICS.

Abstract:

Current simulation and experimental investigatory work is going on into the performance of slicer and lenslet IFS designs. The aim of this work is to determine which technology holds the best promise for achieving the highest contrasts with EPICS on the E-ELT. Results from Spectral Deconvolution methods for high contrast detections are presented, both on sky images from AB Dor C observations using SINFONI on the VLT and improvements to the algorithms made through use of EPICS simulation data. Using these simulations, only containing photon and speckle noise, we have been able to detect simulated planets down to a contrast of 1010 located less than 1" from the parent star. The effects of spectral resolution and wavelength range on high contrast observations are discussed. Shortening the wavelength range increases the inner working angle. It is seen that an outer working angle is also reached that decreases with spectral resolution. The limit on the inner working angle can be overcome partly by increasing the wavelength range of the instrument although another inner working angle limit will be reached if a coronagraph is used. The limit of the outer working angle can also be overcome by increasing the spectral resolution of the instrument or possibly by making an IFS that produces an output with a constant spectral resolution, R,instead of constant Δλ.This is still a work in progress.

Abstract:

FMOS: the Fiber Multiple-Object Spectrograph is the next common-use instrument of the Subaru Telescope, having a capability of 400 targets multiplicity in the near-infrared 0.9-1.8μm wavelength range with a field coverage of 30- diameter. FMOS consists of three units: 1) the prime focus unit including the corrector lenses, the Echidna fiber positioner, and the instrument-bay to adjust the instrument focus and shift the axis of the corrector lens system, 2) the fiber bundle unit equipping two fiber slits on one end and a fiber connector box with the back-illumination mechanism on the other end on the bundle, 3) the two infrared spectrographs (IRS1 and IRS2) to obtain 2×200 spectra simultaneously. After all the components were installed in the telescope at the end of 2007, the total performance was checked through various tests and engineering observations. We report the results of these tests and demonstrate the performance of FMOS.

Abstract:

The dusty molecular torus, cornerstone of the unified model of AGN, has been the subject of much observational and theoretical scrutiny in recent years, and much progress has been made with observations and models aiming to reveal, explain and predict its properties. ©2008: Instituto de Astronomía.