35 research outputs found
Final Design and On-Sky Testing of the iLocater SX Acquisition Camera: Broadband Single-Mode Fiber Coupling
Enabling efficient injection of light into single-mode fibers (SMFs) is a key
requirement in realizing diffraction-limited astronomical spectroscopy on
ground-based telescopes. SMF-fed spectrographs, facilitated by the use of
adaptive optics (AO), offer distinct advantages over comparable seeing-limited
designs, including higher spectral resolution within a compact and stable
instrument volume, and a telescope independent spectrograph design. iLocater is
an extremely precise radial velocity (EPRV) spectrograph being built for the
Large Binocular Telescope (LBT). We have designed and built the front-end fiber
injection system, or acquisition camera, for the SX (left) primary mirror of
the LBT. The instrument was installed in 2019 and underwent on-sky
commissioning and performance assessment. In this paper, we present the
instrument requirements, acquisition camera design, as well as results from
first-light measurements. Broadband single-mode fiber coupling in excess of 35%
(absolute) in the near-infrared (0.97-1.31{\mu}m) was achieved across a range
of target magnitudes, spectral types, and observing conditions. Successful
demonstration of on-sky performance represents both a major milestone in the
development of iLocater and in making efficient ground-based SMF-fed
astronomical instruments a reality.Comment: 18 pages, 17 figures. Accepted for publication in MNRA
Cyclic competition of four species: domains and interfaces
We study numerically domain growth and interface fluctuations in one- and
two-dimensional lattice systems composed of four species that interact in a
cyclic way. Particle mobility is implemented through exchanges of particles
located on neighboring lattice sites. For the chain we find that domain growth
strongly depends on the mobility, with a higher mobility yielding a larger
domain growth exponent. In two space dimensions, when also exchanges between
mutually neutral particles are possible, both domain growth and interface
fluctuations display universal regimes that are independent of the predation
and exchange rates.Comment: 14 pages, 7 figures, version accepted for publication in J. Stat.
Mec
Deformation history of the Western Helvetic Nappes, Valais, Switzerland
Imperial Users onl
Sequence and kinematics of multiple deformation in the Taemas Bridge area, NSW: a preliminary outline
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Sequence and kinematics of multiple deformation around Taemas Bridge, Eastern Lachlan Fold Belt, New South Wales - Reply
5 page(s
Elementary spherical harmonic functions as an aid to solving coupled sliding, interface diffusion and incompressible straining flow around a sphere
Book review : "The techniques of modern structural geology, volume 3: applications of continuum mechanics in structural geology"
4 page(s