Leland G. Engel

The habitable zone planet finder: a proposed high-resolution NIR spectrograph for the Hobby Eberly Telescope to discover low-mass exoplanets around M dwarfs

The Habitable Zone Planet Finder (HZPF) is a proposed instrument for the 10m class Hobby Eberly telescope that will be capable of discovering low mass planets around M dwarfs. HZPF will be fiber-fed, provide a spectral resolution R~ 50,000 and cover the wavelength range 0.9-1.65μm, the Y, J and H NIR bands where most of the flux is emitted by midlate type M stars, and where most of the radial velocity information is concentrated. Enclosed in a chilled vacuum vessel with active temperature control, fiber scrambling and mechanical agitation, HZPF is designed to achieve a radial velocity precision < 3m/s, with a desire to obtain <1m/s for the brightest targets. This instrument will enable a study of the properties of low mass planets around M dwarfs; discover planets in the habitable zones around these stars, as well serve as an essential radial velocity confirmation tool for astrometric and transit detections around late M dwarfs. Radial velocity observation in the near-infrared (NIR) will also enable a search for close in planets around young active stars, complementing the search space enabled by upcoming high-contrast imaging instruments like GPI, SPHERE and PALM3K. Tests with a prototype Pathfinder instrument have already demonstrated the ability to recover radial velocities at 7-10 m/s precision from integrated sunlight and ~15-20 m/s precision on stellar observations at the HET. These tests have also demonstrated the ability to work in the NIR Y and J bands with an un-cooled instrument. We will also discuss lessons learned about calibration and performance from our tests and how they impact the overall design of the HZPF.

A Pathfinder Instrument for Precision Radial Velocities in the Near-Infrared

Original article can be found at : http://www.journals.uchicago.edu/ Copyright Astronomical Society of the Pacific

The Hobby-Eberly Telescope medium resolution spectrograph and fiber instrument feed

The Medium Resolution Spectrograph (MRS) is a versatile, fiber-fed echelle spectrograph for the Hobby-Eberly Telescope (HET). This instrument is designed for a wide range of scientific investigations and includes single-fiber inputs for the study of point-like sources, synthetic slits of fibers for long slit spectroscopy 9 independently positionable probes for multi-object spectroscopy, and a circular fiber integral field unit. The MRS consists of two beams. The visible beam has wavelength coverage from 450 - 900 nm in a single exposure with resolving power between 5,300 and 20,000 depending on the fibers configuration selected. This beam also has capability in the ranges 380 - 950 nm by altering the angles of the cross-disperser gratings. A second beam operating in the near-infrared has coverage of 900 - 1300 nm with resolving power between 5,300 and 10,000. Both beams can be used simultaneously and are fed by the HET Fiber Instrument Feed (FIF) which is mounted at the prime focus of the telescope and positions the fibers feeding the MRS. The MRS started commissioning summer 2002.

Fine-scale features on bioreplicated decoys of the emerald ash borer provide necessary visual verisimilitude

The emerald ash borer (EAB), Agrilus planipennis, is an invasive tree-killing pest in North America. Like other buprestid beetles, it has an iridescent coloring, produced by a periodically layered cuticle whose reflectance peaks at 540 nm wavelength. The males perform a visually mediated ritualistic mating flight directly onto females poised on sunlit leaves. We attempted to evoke this behavior using artificial visual decoys of three types. To fabricate decoys of the first type, a polymer sheet coated with a Bragg-stack reflector was loosely stamped by a bioreplicating die. For decoys of the second type, a polymer sheet coated with a Bragg-stack reflector was heavily stamped by the same die and then painted green. Every decoy of these two types had an underlying black absorber layer. Decoys of the third type were produced by a rapid prototyping machine and painted green. Fine-scale features were absent on the third type. Experiments were performed in an American ash forest infested with EAB, and a European oak forest home to a similar pest, the two-spotted oak borer (TSOB), Agrilus biguttatus. When pinned to leaves, dead EAB females, dead TSOB females, and bioreplicated decoys of both types often evoked the complete ritualized flight behavior. Males also initiated approaches to the rapidly prototyped decoy, but would divert elsewhere without making contact. The attraction of the bioreplicated decoys was also demonstrated by providing a high dc voltage across the decoys that stunned and killed approaching beetles. Thus, true bioreplication with fine-scale features is necessary to fully evoke ritualized visual responses in insects, and provides an opportunity for developing insecttrapping technologies.

CUBIC: x-ray CCD spectroscopy of the diffuse x-ray background

The cosmic unresolved background instrument using CCDs (CUBIC) is currently scheduled for launch on the Argentine/US SAC-B satellite late this year. This instrument is designed to perform moderate resolution nondispersive x-ray spectroscopy of the diffuse x-ray background over the band 0.2 - 10.0 keV using state-of-the-art photon-counting CCDs. The instrument is optimized for spectroscopy of diffuse emission with a field of view of 5 degrees by 5 degrees below 1 keV and 10 degrees by 10 degrees above 3 keV. Observations will typically last 1 - 3 days, and will obtain high quality CCD spectra of the diffuse background, nearby superbubbles and supernova remnants, and the brightest x-ray point sources. This paper gives an overview of the instrument design and CCD detectors.

CUBIC: a nondispersive diffuse x-ray background spectrometer

The Cosmic Unresolved X-ray Background InsLrumenl using CCDs (CUBIC ) is designed to obtain spectral observations of the Diffuse X-ray Background (DXRB) with moderate spectral resolution (E/E 10—60) over the energy range 0.2 — 10 keV using mechanically collimated CCDs. It will be launched on the NASA/Argentine minisat SA C-B in December 1994. At this time, it is the only planned satellite payload devoted to the study of the spectrum of the DXRB. Observations will consist of 1—2 day pointed exposures of each target direction, resulting in a series of high quality spectra. Over the anticipated 3 year lifetime of the satellite, CUBIC will be able to study up to 50% of the sky with 5° x 5° spatial resolution for the subkilovolt Galactic diffuse background, and with 1O x 1O spatial resolution for the extragalactic diffuse background above 2 keV. CUBIC will obtain high quality non-dispersive spectra of soft X-ray emission from the interstellar medium, supernova remnants, and some bright sources, and will make a sensitive search for line emission or other features in the extragalactic cosmic X-ray background from 2 — 10 keY