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The use of theory in research relating to open access: practitioner perspectives
The relationship between theory and practice has long been considered problematic for many applied academic disciplines. In this short paper we report preliminary findings from a two‐year research project investigating the ways and the extent that theory and practice have interacted in the development of open‐access (OA) approaches to the publishing and dissemination of research outputs. Based on interviews with practitioners and researchers working on OA related issues, we explore the ways in which theory is (and isn't) of value to practice. We find that while practitioners acknowledge that theory has the potential to improve understanding, bestow credibility on work, and codify existing knowledge about OA, they also perceive it as “mood music” to the practical work of OA, lacking explicit links to action
Open access in theory and practice : the theory-practice relationship and openness
Open Access in Theory and Practice investigates the theory-practice relationship in the domain of open access publication and dissemination of research outputs.
Drawing on detailed analysis of the literature and current practice in OA, as well as data collected in detailed interviews with practitioners, policymakers, and researchers, the book discusses what constitutes ‘theory’, and how the role of theory is perceived by both theorists and practitioners. Exploring the ways theory and practice have interacted in the development of OA, the authors discuss what this reveals about the nature of the OA phenomenon itself and the theory-practice relationship.
Open Access in Theory and Practice contributes to a better understanding of OA and, as such, should be of great interest to academics, researchers, and students working in the fields of information science, publishing studies, science communication, higher education policy, business, and economics. The book also makes an important contribution to the debate of the relationship between theory and practice in information science, and more widely across different fields of the social sciences and humanitie
Binary frequency of planet-host stars at wide separations: A new brown dwarf companion to a planet-host star
The aim of the project is to improve our knowledge on the multiplicity of
planet-host stars at wide physical separations.
We cross-matched approximately 6200 square degree area of the Southern sky
imaged by the Visible Infrared Survey Telescope for Astronomy (VISTA)
Hemisphere Survey (VHS) with the Two Micron All Sky Survey (2MASS) to look for
wide common proper motion companions to known planet-host stars. We
complemented our astrometric search with photometric criteria.
We confirmed spectroscopically the co-moving nature of seven sources out of
16 companion candidates and discarded eight, while the remaining one stays as a
candidate. Among these new wide companions to planet-host stars, we discovered
a T4.5 dwarf companion at 6.3 arcmin (~9000 au) from HIP70849, a K7V star which
hosts a 9 Jupiter mass planet with an eccentric orbit. We also report two new
stellar M dwarf companions to one G and one metal-rich K star. We infer stellar
and substellar binary frequencies for our complete sample of 37 targets of
5.4+/-3.8% and 2.7+/-2.7% (1 sigma confidence level), respectively, for
projected physical separations larger than ~60-160 au assuming the range of
distances of planet-host stars (24-75 pc). These values are comparable to the
frequencies of non planet-host stars. We find that the period-eccentricity
trend holds with a lack of multiple systems with planets at large
eccentricities (e > 0.2) for periods less than 40 days. However, the lack of
planets more massive than 2.5 Jupiter masses and short periods (<40 days)
orbiting single stars is not so obvious due to recent discoveries by
ground-based transit surveys and space missions.Comment: Accepted for publication in A&A, 13 pages, 5 figures, 3 tables,
optical spectra will be available at CDS Strasbour
Two new ultracool benchmark systems from WISE+2MASS
We have used the Two-Micron All-Sky Survey and the Wide-field Infrared Survey Explorer to look for ultracool dwarfs that are part of multiple systems containing main-sequence stars. We cross-matched L dwarf candidates from the surveys with Hipparcos and Gliese stars, finding two new systems. The first system, G255-34AB, is an L2 dwarf companion to a K8 star, at a distance of 36 pc. We estimate its bolometric luminosity as log L/L-circle dot = -3.78 +/- 0.045 and T-eff = 2080 +/- 260 K. The second system, GJ499ABC, is a triple, with an L5 dwarf as a companion to a binary with an M4 and K5 star. These two new systems bring the number of L dwarf plus main-sequence star multiple systems to 24, which we discuss. We consider the binary fraction for L dwarfs and main-sequence stars, and further assess possible unresolved multiplicity within the full companion sample. This analysis shows that some of the L dwarfs in this sample might actually be unresolved binaries themselves, since their M-J appears to be brighter than the expected for their spectral types.Peer reviewe
Parallaxes and Infrared Photometry of three Y0 dwarfs
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. © 2017 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.We have followed up the three Y0 dwarfs WISEPA J041022.71+150248.5, WISEPA J173835.53+273258.9 and WISEPC J205628.90+145953.3 using the UKIRT/WFCAM telescope/instruments. We find parallaxes that are more consistent and accurate than previously published values. We estimate absolute magnitudes in photometric pass-bands from to and find them to be consistent between the three Y0 dwarfs indicating the inherent cosmic absolute magnitude spread of these objects is small. We examine the MKO magnitudes over the four year time line and find small but significant monotonic variations. Finally we estimate physical parameters from a comparison of spectra and parallax to equilibrium and non-equilibrium models finding values consistent with solar metallicity, an effective temperature of 450-475\,K and log~g of 4.0-4.5.Peer reviewe
Identifying Ultra-Cool Dwarfs at Low Galactic Latitudes: A Southern Candidate Catalogue
We present an Ultra-Cool Dwarf (UCD) catalogue compiled from low southern
Galactic latitudes and mid-plane, from a cross-correlation of the 2MASS and
SuperCOSMOS surveys. The catalogue contains 246 members identified from 5042
sq. deg. within 220 deg. <= l <= 360 deg. and 0 deg. < l <= 30 deg., for |b| <=
15 deg. Sixteen candidates are spectroscopically confirmed in the near-IR as
UCDs with spectral types from M7.5V to L9. Our catalogue selection method is
presented enabling UCDs from ~M8V to the L-T transition to be selected down to
a 2MASS limiting magnitude of Ks ~= 14.5 mag. This method does not require
candidates to have optical detections for catalogue inclusion. An optimal set
of optical/near-IR and reduced proper-motion selection criteria have been
defined that includes: an Rf and Ivn photometric surface gravity test, a dual
Rf-band variability check, and an additional photometric classification scheme
to selectively limit contaminants. We identify four candidates as possible
companions to nearby Hipparcos stars -- observations are needed to identify
these as potential benchmark UCD companions. We also identify twelve UCDs
within a possible distance 20 pc, three are previously unknown of which two are
estimated within 10 pc, complimenting the nearby volume-limited census of UCDs.
An analysis of the catalogue spatial completeness provides estimates for
distance completeness over three UCD MJ ranges, while Monte-Carlo simulations
provide an estimate of catalogue areal completeness at the 75 per cent level.
We estimate a UCD space density of Rho (total) = (6.41+-3.01)x10^3/pc^3 over
the range of 10.5 <= MJ ~< 14.9, similar to values measured at higher Galactic
latitudes (|b| ~> 10 deg.) in the field population and obtained from more
robust spectroscopically confirmed UCD samples.Comment: MNRAS accepted April 2012. Contains 30 figures and 11 tables. Tables
2 and 6 to be published in full and on-line only. The on-line tables can also
be obtained by contacting the author
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