35,882 research outputs found
The Ohio State University Libraries Audiovisual Assessment Interim Report
The 26-month audiovisual (AV) assessment took place from June 2017 to August 2019 with a focus on
rare or unique audiovisual items. Curators and archivists within each unit identified collections or
collecting areas for significance or research value. Approximately 65% of AV materials in seven library
units has not been assessed. Upon completion, 18,389 audiovisual items in 32 distinct formats were
individually assessed
The Dawes Review 1: Kinematic studies of star-forming galaxies across cosmic time
The last seven years have seen an explosion in the number of Integral Field
galaxy surveys, obtaining resolved 2D spectroscopy, especially at
high-redshift. These have taken advantage of the mature capabilities of 8-10 m
class telescopes and the development of associated technology such as AO.
Surveys have leveraged both high spectroscopic resolution enabling internal
velocity measurements and high spatial resolution from AO techniques and sites
with excellent natural seeing. For the first time, we have been able to glimpse
the kinematic state of matter in young, assembling star-forming galaxies and
learn detailed astrophysical information about the physical processes and
compare their kinematic scaling relations with those in the local Universe.
Observers have measured disc galaxy rotation, merger signatures, and
turbulence-enhanced velocity dispersions of gas-rich discs. Theorists have
interpreted kinematic signatures of galaxies in a variety of ways (rotation,
merging, outflows, and feedback) and attempted to discuss evolution vs.
theoretical models and relate it to the evolution in galaxy morphology. A key
point that has emerged from this activity is that substantial fractions of
high-redshift galaxies have regular kinematic morphologies despite irregular
photometric morphologies and this is likely due to the presence of a large
number of highly gas-rich discs. There has not yet been a review of this
burgeoning topic. In this first Dawes review, I will discuss the extensive
kinematic surveys that have been done and the physical models that have arisen
for young galaxies at high-redshift.Comment: 51 pages, 34,000 words, 16 figures. A few minor corrections have been
made to the journal version. High-resolution PDF and iPad optimised ePUB
versions available from http://astronomy.swin.edu.au/karl/dawe
Improved SOT (Hinode mission) high resolution solar imaging observations
We consider the best today available observations of the Sun free of
turbulent Earth atmospheric effects, taken with the Solar Optical Telescope
(SOT) onboard the Hinode spacecraft. Both the instrumental smearing and the
observed stray light are analyzed in order to improve the resolution. The Point
Spread Function (PSF) corresponding to the blue continuum Broadband Filter
Imager (BFI) near 450 nm is deduced by analyzing i/ the limb of the Sun and ii/
images taken during the transit of the planet Venus in 2012. A combination of
Gaussian and Lorentzian functions is selected to construct a PSF in order to
remove both smearing due to the instrumental diffraction effects (PSF core) and
the large-angle stray light due to the spiders and central obscuration (wings
of the PSF) that are responsible for the parasitic stray light. A
Max-likelihood deconvolution procedure based on an optimum number of iterations
is discussed. It is applied to several solar field images, including the
granulation near the limb. The normal non-magnetic granulation is compared to
the abnormal granulation which we call magnetic. A new feature appearing for
the first time at the extreme- limb of the disk (the last 100 km) is discussed
in the context of the definition of the solar edge and of the solar diameter. A
single sunspot is considered in order to illustrate how effectively the
restoration works on the sunspot core. A set of 125 consecutive deconvolved
images is assembled in a 45 min long movie illustrating the complexity of the
dynamical behavior inside and around the sunspot.Comment: 15 pages, 22 figures, 1 movi
Kinematically Detected Halo Streams
Clues to the origins and evolution of our Galaxy can be found in the
kinematics of stars around us. Remnants of accreted satellite galaxies produce
over- densities in velocity-space, which can remain coherent for much longer
than spatial over-densities. This chapter reviews a number of studies that have
hunted for these accretion relics, both in the nearby solar-neighborhood and
the more-distant stellar halo. Many observational surveys have driven this
field forwards, from early work with the Hipparcos mission, to contemporary
surveys like RAVE & SDSS. This active field continues to flourish, providing
many new discoveries, and will be revolutionised as the Gaia mission delivers
precise proper motions for a billion stars in our Galaxy.Comment: 27 pages, 10 figures. Chapter from Springer ASSL Volume entitled
"Tidal Streams in the Local Group and Beyond". Affluent readers may wish to
purchase the full volume here:
http://link.springer.com/book/10.1007/978-3-319-19336-
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