173 research outputs found
Probing the high momentum component of the deuteron at high Q^2
The d(e,e'p) cross section at a momentum transfer of 3.5 (GeV/c)^2 was
measured over a kinematical range that made it possible to study this reaction
for a set of fixed missing momenta as a function of the neutron recoil angle
theta_nq and to extract missing momentum distributions for fixed values of
theta_nq up to 0.55 GeV/c. In the region of 35 (deg) <= theta_nq <= 45 (deg)
recent calculations, which predict that final state interactions are small,
agree reasonably well with the experimental data. Therefore these experimental
reduced cross sections provide direct access to the high momentum component of
the deuteron momentum distribution in exclusive deuteron
electro-disintegration.Comment: 5 pages, 2 figure
The First VERITAS Telescope
The first atmospheric Cherenkov telescope of VERITAS (the Very Energetic
Radiation Imaging Telescope Array System) has been in operation since February
2005. We present here a technical description of the instrument and a summary
of its performance. The calibration methods are described, along with the
results of Monte Carlo simulations of the telescope and comparisons between
real and simulated data. The analysis of TeV -ray observations of the
Crab Nebula, including the reconstructed energy spectrum, is shown to give
results consistent with earlier measurements. The telescope is operating as
expected and has met or exceeded all design specifications.Comment: Accepted by Astroparticle Physic
The Life and Death of Barn Beetles: Faunas from Manure and Stored Hay inside Farm Buildings in Northern Iceland
This research was funded by the Commonwealth Scholarship Commission and received support from the Research Budget of the Department of Archaeology at the University of Aberdeen. This project was undertaken as part of doctoral studies supervised by Dr Karen Milek, to whom V.F. is especially grateful for her support and advice. Thomas Birch, SigrĂșn Inga GarĂ°arsdĂłttir, and Paul Ledger provided invaluable assistance during fieldwork. V.F. would like to dedicate this paper to Tom and SĂa, who met during this fieldwork and are getting married this year. Many people from Fornleifastofnun Ăslands â GarĂ°ar GuĂ°mundsson, Ălöf ĂorsteinsdĂłttir, ĂĂłra PĂ©tursdĂłttir, Adolf FriĂ°riksson and Uggi Ăvarsson â as well as Unnstein Ingason, ĂgĂșsta Edwald, and Mark Young, helped with fieldwork logistics. Special thanks are due to all the Icelandic farmers and their families who kindly allowed us to collect insects on their farms and provided help when needed: Hermann AĂ°alsteinsson, HermĂna FjĂłla IngĂłlfsdĂłttir, GuĂ°mundur SkĂșlason, SigrĂșn Ă. FranzdĂłttir, DĂșna MagnĂșsdĂłttir, Sverrir Steinbergsson, Valgeir Ăorvaldsson, Reynir Sveinsson, JĂłnas ĂĂłr IngĂłlfsson, and Ăvar Ălafsson. Eva Panagiotakopulu, Jan Klimaszewski, Ales Smetana, Georges Pelletier, Gabor Pozsgai, and Jenni Stockham helped with some of the beetle identifications. A.J.D. acknowledges the support of National Science Foundation through ARC 1202692. Consultation of the BugsCEP database (Buckland & Buckland, 2006) aided the redaction of this paper. The authors would like to thank David Smith and two anonymous reviewers for insightful comments that helped improve the quality of this paper.Peer reviewedPostprin
The XMM Cluster Survey: Exploring scaling relations and completeness of the Dark Energy Survey Year 3 redMaPPer cluster catalogue
We cross-match and compare characteristics of galaxy clusters identified in
observations from two sky surveys using two completely different techniques.
One sample is optically selected from the analysis of three years of Dark
Energy Survey observations using the redMaPPer cluster detection algorithm. The
second is X-ray selected from XMM observations analysed by the XMM Cluster
Survey. The samples comprise a total area of 57.4 deg, bounded by the area
of 4 contiguous XMM survey regions that overlap the DES footprint. We find that
the X-ray selected sample is fully matched with entries in the redMaPPer
catalogue, above 20 and within 0.10.9. Conversely, only 38\%
of the redMaPPer catalogue is matched to an X-ray extended source. Next, using
120 optically clusters and 184 X-ray selected clusters, we investigate the form
of the X-ray luminosity-temperature (), luminosity-richness
() and temperature-richness () scaling relations.
We find that the fitted forms of the relations are consistent
between the two selection methods and also with other studies in the
literature. However, we find tentative evidence for a steepening of the slope
of the relation for low richness systems in the X-ray selected sample. When
considering the scaling of richness with X-ray properties, we again find
consistency in the relations (i.e., and )
between the optical and X-ray selected samples. This is contrary to previous
similar works that find a significant increase in the scatter of the luminosity
scaling relation for X-ray selected samples compared to optically selected
samples.Comment: Accepted for publication to MNRA
The British Army, information management and the First World War revolution in military affairs
Information Management (IM) â the systematic ordering, processing and channelling of information within organisations â forms a critical component of modern military command and control systems. As a subject of scholarly enquiry, however, the history of military IM has been relatively poorly served. Employing new
and under-utilised archival sources, this article takes the British Expeditionary Force (BEF) of the First World War as its case study and assesses the extent to which its IM system contributed to the emergence of the modern battlefield in 1918. It argues that the
demands of fighting a modern war resulted in a general, but not universal, improvement in the BEFâs IM techniques, which in turn laid the groundwork, albeit in embryonic form, for the IM systems of modern armies.
KEY WORDS: British Army, Information Management, First World War, Revolution in Military Affairs, Adaptatio
Quasielastic (e,eâČp) reaction on 12C,56Fe, and 197Au
We report the results from a systematic study of the quasielastic (e,eâČp) reaction on 12C, 56Fe, and 197Au performed at Jefferson Lab. We have measured nuclear transparency and extracted spectral functions (corrected for radiation) over a Q2 range of 0.64â3.25 (GeVâc)2 for all three nuclei. In addition, we have extracted separated longitudinal and transverse spectral functions at Q2 of 0.64 and 1.8 (GeVâc)2 for these three nuclei (except for 197Au at the higher Q2). The spectral functions are compared to a number of theoretical calculations. The measured spectral functions differ in detail but not in overall shape from most of the theoretical models. In all three targets the measured spectral functions show considerable excess transverse strength at Q2=0.64 (GeVâc)2, which is much reduced at 1.8 (GeVâc)2
Separated spectral functions for the quasifree 12C(e,eâČp) reaction
A separation of the longitudinal and transverse 12C(e,eâČp) cross sections in the quasifree region has been performed in parallel kinematics at Q2 of 0.64 and 1.8 GeV2 for initial proton momentum <80 MeV. The separated transverse and longitudinal spectral functions at Q2=0.64GeV2 show significant differences for missing energy between 25 and 60 MeV indicating a breakdown in the single nucleon knockout picture. The transverse spectral functions exhibit definite momentum transfer dependence
The Atacama Cosmology Telescope: A Catalog of >4000 SunyaevâZelâdovich Galaxy Clusters
We present a catalog of 4195 optically confirmed SunyaevâZel'dovich (SZ) selected galaxy clusters detected with signal-to-noise ratio >4 in 13,211 deg2 of sky surveyed by the Atacama Cosmology Telescope (ACT). Cluster candidates were selected by applying a multifrequency matched filter to 98 and 150 GHz maps constructed from ACT observations obtained from 2008 to 2018 and confirmed using deep, wide-area optical surveys. The clusters span the redshift range 0.04 1 clusters, and a total of 868 systems are new discoveries. Assuming an SZ signal versus mass-scaling relation calibrated from X-ray observations, the sample has a 90% completeness mass limit of M500c > 3.8 Ă 1014 Mâ, evaluated at z = 0.5, for clusters detected at signal-to-noise ratio >5 in maps filtered at an angular scale of 2farcm4. The survey has a large overlap with deep optical weak-lensing surveys that are being used to calibrate the SZ signal mass-scaling relation, such as the Dark Energy Survey (4566 deg2), the Hyper Suprime-Cam Subaru Strategic Program (469 deg2), and the Kilo Degree Survey (825 deg2). We highlight some noteworthy objects in the sample, including potentially projected systems, clusters with strong lensing features, clusters with active central galaxies or star formation, and systems of multiple clusters that may be physically associated. The cluster catalog will be a useful resource for future cosmological analyses and studying the evolution of the intracluster medium and galaxies in massive clusters over the past 10 Gyr
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