arXiv subjects

Todd J. Veach

Publications and source records attributed to Todd J. Veach.

3 recordsLinked to original sources

arXiv2026

The Ultraviolet Spectrograph on ESA's Jupiter Icy Moons Explorer Mission (JUICE-UVS)

The Jupiter Icy Moons Explorer (JUICE) mission, led by ESA, has an Ultraviolet Spectrograph (JUICE-UVS) contributed by NASA and built at Southwest Research Institute. JUICE-UVS is designed to provide a diversity of measurements to further our understanding of the potential habitability of icy ocean worlds at Jupiter and to study Jupiter and the Jovian system as an archetype for gas giants. JUICE-UVS observes photons in the 50-204 nm wavelength range at moderate spectral and spatial resolution along a 7.5 deg slit composed of 7.3 deg x 0.1 deg and 0.2 deg x 0.2 deg contiguous sections. JUICE-UVS performs a comprehensive study of icy satellite atmospheres, plumes, surfaces, and local space environments; Jupiter's atmosphere and aurora; Io and its Io Plasma Torus; and other Jupiter system targets (rings, small moons, etc.) as available. The variety of observational techniques employed include: nadir push-broom imaging, disk scans, limb stares, stellar and solar occultations, Jupiter transit observations, and neutral cloud/plasma torus stares and scans. This paper describes the UVS investigation's science plans, instrument details, concept of operations, and data formats in the context of the JUICE mission's habitability and Jupiter system goals.

astro-ph.EP↗

arXiv2015

Far-Infrared double-Fourier interferometers and their spectral sensitivity

Double-Fourier interferometry is the most viable path to sub-arcsecond spatial resolution for future astronomical instruments that will observe the universe at far-infrared wavelengths. The double transform spatio-spectral interferometry couples pupil plane beam combination with detector arrays to enable imaging spectroscopy of wide fields, that will be key to accomplishing top-level science goals. The wide field of view and the necessity for these instruments to fly above the opaque atmosphere create unique characteristics and requirements compared to instruments on ground-based telescopes. In this paper, we discuss some characteristics of single-baseline spatio-spectral interferometers. We investigate the impact of intensity and optical path difference noise on the interferogram and the spectral signal-to-noise ratio. We apply our findings to the special case of the Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII), a balloon payload that will be a first application of this technique at far-infrared wavelengths on a flying platform.

astro-ph.IM↗

arXiv2013

Vibrationally Excited HCN around AFGL 2591: A Probe of Protostellar Structure

Vibrationally excited molecules with sub-mm rotational transitions are potentially excellent probes of physical conditions near protostars. This study uses observations of the v=1 and v=2 ro-vibrational modes of HCN (4-3) to probe this environment. The presence or absence and relative strengths of these ro-vibrational lines probe the gas excitation mechanism and physical conditions in warm, dense material associated with protostellar disks. We present pilot observations from the Heinrich Hertz Submillimeter Telescope (HHSMT) and followup observations from the Submillimeter Array (SMA). All vibrationally excited HCN (4-3) v=0, v=1, and v=2 lines were observed. The existence of the three v=2 lines at approximately equal intensity imply collisional excitation with a density of greater than (10^10 cm^-3) and a temperature of >1000 K for the emitting gas. This warm, high density material should directly trace structures formed in the protostellar envelope and disk environment. Further, the line shapes of the v=2 emission may suggest a Keplerian disk. This letter demonstrates the utility of this technique which is of particular interest due to the recent inauguration of the Atacama Large Millimeter Array (ALMA).

astro-ph.SR↗