Exoplanet atmospheres

Abstract:

We describe the design of a 2nd generation instrument for the ESO VLT which uses 24 cryogenic pickoff arms linked to diamond-machined image slicing integral field units to deliver a unique multiple deployable integral field capability in the near-infrared (1-2.5 mu m). The science requirements for the instrument are presented and linked to the functional specification. The baseline instrument concept is described with emphasis on technological innovations. (c) 2006 Elsevier B.V. All rights reserved.

Abstract:

The band model fits of Sihra [1998. Ph.D. Thesis. University of Oxford], subsequently reported by Irwin et al. [2005. Icarus 176, 255-271], to new measurements of low-temperature near-infrared self-broadened methane absorption spectra combined with earlier warmer, longer path measurements of both self- and hydrogen-broadened methane spectra measured by Strong et al. [1993. J. Quant. Spectrosc. Radiat. Transfer 50, 363-429], have been found to contain severe artefacts at wavelengths of very low methane absorption. Although spectra calculated from these new band data appear to be reliable for paths with low to medium absorption, transmissions calculated for long paths of high methane absorption, such as for Uranus, Neptune and Titan are severely compromised. The recorded laboratory transmission spectra of Sihra [1998. Ph.D. Thesis. University of Oxford] and Strong et al. [1993. J. Quant. Spectrosc. Radiat. Transfer 50, 363-429] have thus been refitted with a more robust model and new k-distribution data for both self- and hydrogen-broadened methane absorption derived. In addition, a new model of the temperature dependence of the absorption has been employed that improves the quality of the fit and should also provide more accurate extrapolations to low temperatures. © 2005 Elsevier Inc. All rights reserved.

Abstract:

Magnetoencephalography (MEG) is a non-invasive technique of functional imaging which measures weak magnetic fields in the brain due to the currents generated from neural synapses. MEG systems contain a couple of hundred channels, making it difficult to visualize the raw measurements directly. As an alternative to rendering epileptic data, we demonstrate how MEG measurements can be mapped to a cortical surface by using a software package called FreeSurfer. We fuse MEG data with Magnetic Resonance Image (MRI) by plotting the MEG amplitude on top of the MRI images of gray matter surface. In addition to the surface, we render the MEG intensity in the convoluted regions, e.g. sulci, by computationally "inflating" the brain. These techniques are utilized for experimental study currently, and can be extended for diagnostic purposes in the future. © 2006 IEEE.