Reflective Toraldo pupil for high-resolution millimeter-wave astronomy.

A novel, to the best of our knowledge, beam-shaping reflective surface for high-resolution millimeter/submillimeter-wave astronomy instruments is presented. The reflector design is based on Toraldo's super-resolution principle and implemented with annulated binary-phase coronae structure inspired by the achromatic magnetic mirror approach. A thin, less than half a free-space wavelength, reflective Toraldo pupil device operated in the W-band has been fabricated using mesh-filter technology developed at Cardiff University.

Design of discrete and continuous super-resolving Toraldo pupils in the microwave range.

The concept of super-resolution refers to various methods for improving the angular resolution of an optical imaging system beyond the classical diffraction limit. In optical microscopy, several techniques have been successfully developed with the aim of narrowing the central lobe of the illumination point spread function. In astronomy, however, no similar techniques can be used.

Over half of the far-infrared background light comes from galaxies at z >or= 1.2.

Submillimetre surveys during the past decade have discovered a population of luminous, high-redshift, dusty starburst galaxies. In the redshift range 1 View Article and Find Full Text PDF

Ray-tracing and physical-optics analysis of the aperture efficiency in a radio telescope.

The performance of telescope systems working at microwave or visible-IR wavelengths is typically described in terms of different parameters according to the wavelength range. Most commercial ray-tracing packages have been specifically designed for use with visible-IR systems and thus, though very flexible and sophisticated, do not provide the appropriate parameters to fully describe microwave antennas and to compare with specifications. We demonstrate that the Strehl ratio is equal to the phase efficiency when the apodization factor is taken into account.

Infall of gas as the formation mechanism of stars up to 20 times more massive than the Sun.

Theory predicts and observations confirm that low-mass stars (like the Sun) in their early life grow by accreting gas from the surrounding material. But for stars approximately 10 times more massive than the Sun (approximately 10M(o)), the powerful stellar radiation is expected to inhibit accretion and thus limit the growth of their mass. Clearly, stars with masses >10M(o) exist, so there must be a way for them to form.