10 research outputs found
A Generalist, Automated ALFALFA Baryonic Tully-Fisher Relation
The Baryonic Tully-Fisher Relation (BTFR) has applications in galaxy
evolution as a testbed for the galaxy-halo connection and in observational
cosmology as a redshift-independent secondary distance indicator. We use the
31,000+ galaxy ALFALFA sample -- which provides redshifts, velocity widths, and
HI content for a large number of gas-bearing galaxies in the local universe --
to fit and test an extensive local universe BTFR. This BTFR is designed to be
as inclusive of ALFALFA and comparable samples as possible. Velocity widths
measured via an automated method and proxies extracted from survey data
can be uniformly and efficiently measured for other samples, giving this
analysis broad applicability. We also investigate the role of sample
demographics in determining the best-fit relation. We find that the best-fit
relations are changed significantly by changes to the sample mass range and to
second order, mass sampling, gas fraction, different stellar mass and velocity
width measurements. We use a subset of ALFALFA with demographics that reflect
the full sample to measure a robust BTFR slope of . We apply this
relation and estimate source distances, finding general agreement with
flow-model distances as well as average distance uncertainties of
dex for the full ALFALFA sample. We demonstrate the utility of these distance
estimates by applying them to a sample of sources in the Virgo vicinity,
recovering signatures of infall consistent with previous work.Comment: 23 pages, 10 figures, submitted to Ap
The Arecibo Legacy Fast ALFA Survey: The alpha.40 HI Source Catalog, its Characteristics and their Impact on the Derivation of the HI Mass Function
We present a current catalog of 21 cm HI line sources extracted from the
Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA) survey over ~2800
square degrees of sky: the alpha.40 catalog. Covering 40% of the final survey
area, the alpha.40 catalog contains 15855 sources in the regions 07h30m < R.A.
< 16h30m, +04 deg < Dec. < +16 deg and +24 deg < Dec. < +28 deg and 22h < R.A.
< 03h, +14 deg < Dec. < +16 deg and +24 deg < Dec. < +32 deg. Of those, 15041
are certainly extragalactic, yielding a source density of 5.3 galaxies per
square degree, a factor of 29 improvement over the catalog extracted from the
HI Parkes All Sky Survey. In addition to the source centroid positions, HI line
flux densities, recessional velocities and line widths, the catalog includes
the coordinates of the most probable optical counterpart of each HI line
detection, and a separate compilation provides a crossmatch to identifications
given in the photometric and spectroscopic catalogs associated with the Sloan
Digital Sky Survey Data Release 7. Fewer than 2% of the extragalactic HI line
sources cannot be identified with a feasible optical counterpart; some of those
may be rare OH megamasers at 0.16 < z < 0.25. A detailed analysis is presented
of the completeness, width dependent sensitivity function and bias inherent in
the current alpha.40 catalog. The impact of survey selection, distance errors,
current volume coverage and local large scale structure on the derivation of
the HI mass function is assessed. While alpha.40 does not yet provide a
completely representative sampling of cosmological volume, derivations of the
HI mass function using future data releases from ALFALFA will further improve
both statistical and systematic uncertainties.Comment: 62 pages, 28 figures. See http://egg.astro.cornell.edu/alfalfa/data
for ASCII and CSV datafiles corresponding to Tables 1, 2 and 3. A higher
resolution PDF version can be found at
http://egg.astro.cornell.edu/alfalfa/pubs.php. To appear in Nov 2011 Astron.
The arecibo legacy fast ALFA survey: The ALFALFA extragalactic HI source catalog
We present the catalog of ∼31,500 extragalactic H i line sources detected by the completed Arecibo Legacy Fast ALFA (ALFALFA) survey out to z 6.5) detections and ones of lower quality that coincide in both position and recessional velocity with galaxies of known redshift. We review the observing technique, data reduction pipeline, and catalog construction process, focusing on details of particular relevance to understanding the catalog's compiled parameters. We further describe and make available the digital H i line spectra associated with the cataloged sources. In addition to the extragalactic H i line detections, we report nine confirmed OH megamasers (OHMs) and 10 OHM candidates at 0.16 < z < 0.22 whose OH line signals are redshifted into the ALFALFA frequency band. Because of complexities in data collection and processing associated with the use of a feed-horn array on a complex single-dish antenna in the terrestrial radio frequency interference environment, we also present a list of suggestions and caveats for consideration by users of the ALFALFA extragalactic catalog for future scientific investigations.© 2018. The American Astronomical Society. All rights reserved.The authors acknowledge the work of the entire ALFALFA collaboration who have contributed to the many aspects of the survey over the years. The ALFALFA team at Cornell has been supported by NSF grants AST-0607007, AST-1107390, and AST-1714828 and grants from the Brinson Foundation. Participation of the Undergraduate ALFALFA Team has been made possible by NSF grants AST-0724918, AST-0725267, AST-0725380, AST-0902211, AST-0903394, AST-1211005, AST-1637339, AST-1637271, AST-1637299, AST-1637262, and AST-1637276. EAKA is supported by the WISE research program, which is financed by the Netherlands Organisation for Scientific Research (NWO). BRK acknowledges the National Radio Astronomy Observatory (NRAO). The NRAO is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. MGJ acknowledges support from grant AYA2015-65973-C3-1-R (MINECO/FEDER, UE). We thank Dmitry Makarov for comments and suggestions on cross-identifications.
This work is based on observations made with the Arecibo Observatory. The Arecibo Observatory has been operated by SRI International under a cooperative agreement with the National Science Foundation (AST-1100968) and in alliance with Ana G. Mendez-Universidad Metropolitana and the Universities Space Research Association. We thank the staff of the Arecibo Observatory, especially Phil Perillat, Ganesh Rajagopalan, Arun Venkataraman, Hector Hernandez, and the telescope operations group for their outstanding support of the ALFALFA survey program.
We acknowledge the use of NASA's SkyView facility (http://skyview.gsfc.nasa.gov), located at NASA Goddard Space Flight Center, and the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. The Digitized Sky Surveys were produced at the Space Telescope Science Institute under U.S. Government grant NAG W-2166. The images of these surveys are based on photographic data obtained using the Oschin Schmidt Telescope on Palomar Mountain and the UK Schmidt Telescope. The plates were processed into the present compressed digital form with the permission of these institutions. The Second Palomar Observatory Sky Survey (POSS-II) was made by the California Institute of Technology with funds from the National Science Foundation, the National Geographic Society, the Sloan Foundation, the Samuel Oschin Foundation, and the Eastman Kodak Corporation.
This research used data from the Sloan Digital Sky Survey. Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England
The Arecibo Legacy Fast ALFA Survey:The alpha.40 HI Source Catalog, its Characteristics and their Impact on the Derivation of the HI Mass Function
The Arecibo Legacy Fast ALFA Survey:The ALFALFA Extragalactic HI Source Catalog
We present the catalog of ~31500 extragalactic HI line sources detected by
the completed ALFALFA survey out to z < 0.06 including both high
signal-to-noise ratio (> 6.5) detections and ones of lower quality which
coincide in both position and recessional velocity with galaxies of known
redshift. We review the observing technique, data reduction pipeline, and
catalog construction process, focusing on details of particular relevance to
understanding the catalog's compiled parameters. We further describe and make
available the digital HI line spectra associated with the catalogued sources.
In addition to the extragalactic HI line detections, we report nine confirmed
OH megamasers and ten OH megamaser candidates at 0.16 < z < 0.22 whose OH line
signals are redshifted into the ALFALFA frequency band. Because of complexities
in data collection and processing associated with the use of a feed-horn array
on a complex single-dish antenna in the terrestrial radio frequency
interference environment, we also present a list of suggestions and caveats for
consideration by users of the ALFALFA extragalactic catalog for future
scientific investigations.Comment: 24 pages 8 figures See http://egg.astro.cornell.edu/alfalfa/data for
ASCII and CSV datafiles corresponding to Table 2. To appear in
Astrophys.J.Supp
The Arecibo Legacy Fast ALFA Survey:The alpha.40 HI Source Catalog, its Characteristics and their Impact on the Derivation of the HI Mass Function
ALFALFA extragalactic HI source catalog
VizieR online Data Catalogue associated with article published in journal Astronomical Journal (AAS) with title 'The Arecibo Legacy Fast ALFA survey: The ALFALFA extragalactic HI source catalog.' (bibcode: 2018ApJ...861...49H
A Single Group Follow-Up Study of Non-Surgical Patients Seen by Physiotherapists Working in Expanded Roles in Orthopaedic Departments: Recall of Recommendations, Change in Exercise and Self-Efficacy
Background
Specially trained physiotherapists (advanced practice physiotherapists (APP)) are working in orthopaedic clinics to improve access to orthopaedic services and support chronic disease management. Little attention has been paid to the impact APPs may have on non-surgical patients. In non-surgical patients with hip or knee arthritis consulting an APP in an orthopaedic clinic, the objectives were to: 1) describe patients’ recall of APP recommendations, use of self-management strategies, and barriers to management six weeks following consultation; and, 2) compare exercise behaviour and self-efficacy at baseline and six weeks.
Findings
This was a single group pre-and post-intervention study of patients who saw an APP when consulting the orthopaedic departments of two hospitals. At baseline and six weeks participants completed the adapted Stanford Exercise Behaviour Scale (response options: none, 3 hours/week), and the Chronic Disease Self-efficacy Scale (range 1–10; higher scores indicate higher self-efficacy). At follow-up participants completed questions on recall of APP recommendations, use of self-management strategies and barriers to management. Seventy three non-surgical patients with hip or knee arthritis participated, a response rate of 89% at follow-up. Seventy one percent of patients reported that the APP recommended exercise, of whom 83% reported exercising to manage their arthritis since the visit. Almost 50% reported an increase in time spent stretching; over 40% reported an increase in time spent walking or doing strengthening exercises at follow-up. Common barriers to arthritis management were time, cost and other health problems. Mean chronic disease self-efficacy scores significantly improved from 6.3 to 7.2 (p<0.001). The mean difference was 0.95 (95% CI 0.43, 1.62); the effect size was 0.51.
Conclusions
This pilot study of an APP intervention for non-surgical patients referred for orthopaedic consultation showed promising results, particularly for enhancing use of conservative management strategies such as exercise.Canadian Institutes of Health Research (CIHR