161 research outputs found
HUD Homes: How they Can Promote Home Ownership and Reduce House Abandonment
For many, the American Dream still means owning a home. The home ownership rate in the U.S. fell in the fourth quarter of 2007 to its lowest level since the beginning of 2002--this from a record high in the middle of 2004. What is more alarming, however, is that the home owner vacancy rate went up 2.8 percent. The bulk of the vacant homes are foreclosed homes. Among such foreclosed homes are Department of Housing and Urban Development (HUD) homes that have come into HUD’s possession as a result of Federal Housing Administration (FHA) loan defaults
Meeting the Challenges of an Aging Population with Success
With 117,099 people over the age of 65, Franklin County has the second-highest number of seniors among all Ohio counties. Projection data from the Ohio Department of Development indicates that Franklin County's 65-and-over population will grow to 224,340 by the year 2040. Key findings from this report indicate that improved coordination between the complex web of federal, state, county, and municipal resources would have significant impact on seniors' health and quality of life. The report also includes an analysis of the most vulnerable seniors in Franklin County identified at the neighborhood level
The Impact of Patchy Reionization on Ultra-faint Dwarf Galaxies
We investigate how patchy reionization affects the star formation history
(SFH) and stellar metallicity of ultra-faint dwarf galaxies (UFDs). Patchy
reionization refers to varying ultraviolet (UV) background strengths depending
on a galaxy's environment. Recent observations highlight the significance of
this effect on UFDs, as UFDs can have different SFHs depending on their
relative position with respect to their host halo during the period of
reionization. However, most cosmological hydrodynamic simulations do not
consider environmental factors such as patchy reionization, and the effect of
reionization is typically applied homogeneously. Using a novel approach to
implement patchy reionization, we show how SFHs of simulated UFDs can change.
Our cosmological hydrodynamic zoom-in simulations focus on UFD analogs with
M_vir~10^9solar mass, M_star < 10^5 solar mass at . We find that patchy
reionization can weaken the effect of reionization by two orders of magnitude
up to , enabling late star formation in half of the simulated UFDs, with
quenching times 460 Myr later than those with homogeneous reionization.
We also show that halo merger and mass assembly can affect the SFHs of
simulated UFDs, in addition to patchy reionization. The average stellar
iron-to-hydrogen ratio, [Fe/H], of the simulated UFDs with patchy reionization
increases by 0.22-0.42 dex. Finally, our findings suggest that patchy
reionization could be responsible for the extended SFHs of Magellanic UFDs
compared to non-Magellanic UFDs.Comment: 27 pages, 16 figures, Accepted for publication in Astrophysical
Journa
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Overview of the DESI Legacy Imaging Surveys
The DESI Legacy Imaging Surveys (http://legacysurvey.org/) are a combination of three public projects (the Dark Energy Camera Legacy Survey, the Beijing–Arizona Sky Survey, and the Mayall z-band Legacy Survey) that will jointly image ≈14,000 deg2 of the extragalactic sky visible from the northern hemisphere in three optical bands (g, r, and z) using telescopes at the Kitt Peak National Observatory and the Cerro Tololo Inter-American Observatory. The combined survey footprint is split into two contiguous areas by the Galactic plane. The optical imaging is conducted using a unique strategy of dynamically adjusting the exposure times and pointing selection during observing that results in a survey of nearly uniform depth. In addition to calibrated images, the project is delivering a catalog, constructed by using a probabilistic inference-based approach to estimate source shapes and brightnesses. The catalog includes photometry from the grz optical bands and from four mid-infrared bands (at 3.4, 4.6, 12, and 22 μm) observed by the Wide-field Infrared Survey Explorer satellite during its full operational lifetime. The project plans two public data releases each year. All the software used to generate the catalogs is also released with the data. This paper provides an overview of the Legacy Surveys project.U.S. Department of Energy; U.S. National Science Foundation; Ministry of Science and Education of Spain; Science and Technology Facilities Council of the United Kingdom; Higher Education Funding Council for England; National Center for Super computing Applications at the University of Illinois at Urbana-Champaign; Kavli Institute of Cosmological Physics at the University of Chicago; Center for Cosmology and Astro-Particle Physics at the Ohio State University; Mitchell Institute for Fundamental Physics and Astronomy at Texas AM University; Financiadora de Estudos e Projetos; Fundacao Carlos Chagas Filho de Amparo; Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico; Ministerio da Ciencia, Tecnologia e Inovacao; Deutsche Forschungsgemeinschaft; Argonne National Laboratory; University of California at Santa Cruz; University of Cambridge; Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas-Madrid; University of Chicago; University College London; DES-Brazil Consortium; University of Edinburgh; Eidgenossische Technische Hochschule (ETH) Zurich; Fermi National Accelerator Laboratory; University of Illinois at Urbana-Champaign; Institut de Ciencies de l'Espai (IEEC/CSIC); Institut de Fisica d'Altes Energies; Lawrence Berkeley National Laboratory; Ludwig-Maximilians Universitat Munchen; associated Excellence Cluster Universe; University of Michigan; National Optical Astronomy Observatory; University of Nottingham; Ohio State University; University of Pennsylvania; University of Portsmouth; SLAC National Accelerator Laboratory; Stanford University; University of Sussex; Texas AM University; National Astronomical Observatories of China; Chinese Academy of Sciences [XDB09000000, 114A11KYSB20160057]; Special Fund for Astronomy from the Ministry of Finance; Chinese National Natural Science Foundation [11433005]; Office of Science, Office of High Energy Physics of the U.S. Department of Energy [DE-AC02-05CH11231]; National Energy Research Scientific Computing Center; DOE Office of Science User Facility; U.S. National Science Foundation, Division of Astronomical Sciences [AST-0950945]; National Aeronautics and Space Administration through the Planetary Science Division of the NASA Science Mission Directorate [NNX08AR22G]; National Science Foundation [AST-1238877, AST-1616414, PHY-1066293]; National Aeronautics and Space Administration; Office of Science of the U.S. Department of Energy [DE-AC02-05CH11231]; European Research Council under the European Union/ERC [320964]; Radcliffe Institute for Advanced StudyThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Climatological Features of Korea-Landfalling Tropical Cyclones
The present study analyzed the interdecadal variation by applying the statistical change-point analysis to the frequency of the tropical cyclone (TC) that landed in the Korean Peninsula (KP) for the recent 54 years (1951 to 2004) and performed cluster classification of the Korea-landfall TC tracks using a Fuzzy Clustering Method (FCM). First, in the interdecadal variation analysis, frequency of TC that landed in the KP was largely categorized into three periods: high frequency period from 1951 to 1965, low frequency period from 1966 to 1985, and high frequency period from 1986 to 2004. The cluster analysis result of the Korea-landfall TC tracks produced the optimum number of clusters as four. In more detail, Cluster A refers to a pattern of landing in the southern coast in the KP starting from East China Sea followed by heading north while Cluster B refers to a pattern of landing in the west coast of the Korean Peninsula, also starting from East China Sea followed by heading north. Cluster C refers to a pattern of landing in the southern region of the west coast in the KP moving from mainland China while Cluster D refers to a pattern of landing in the mid-north region of the west coast in the Korean Peninsula, also moving from mainland China
The Panchromatic Hubble Andromeda Treasury XI: The Spatially-Resolved Recent Star Formation History of M31
We measure the recent star formation history (SFH) across M31 using optical
images taken with the \texit{Hubble Space Telescope} as part of the
Panchromatic Hubble Andromeda Treasury (PHAT). We fit the color-magnitude
diagrams in ~9000 regions that are ~100 pc 100 pc in projected size,
covering a 0.5 square degree area (~380 kpc, deprojected) in the NE
quadrant of M31. We show that the SFHs vary significantly on these small
spatial scales but that there are also coherent galaxy-wide fluctuations in the
SFH back to ~500 Myr, most notably in M31's 10-kpc star-forming ring. We find
that the 10-kpc ring is at least 400 Myr old, showing ongoing star formation
over the past ~500 Myr. This indicates the presence of molecular gas in the
ring over at least 2 dynamical times at this radius. We also find that the
ring's position is constant throughout this time, and is stationary at the
level of 1 km/s, although there is evidence for broadening of the ring due to
diffusion of stars into the disk. Based on existing models of M31's ring
features, the lack of evolution in the ring's position makes a purely
collisional ring origin highly unlikely. We find that the global SFR has been
fairly constant over the last ~500 Myr, though it does show a small increase at
50 Myr that is 1.3 times the average SFR over the past 100 Myr. During the last
~500 Myr, ~60% of all SF occurs in the 10-kpc ring. Finally, we find that in
the past 100 Myr, the average SFR over the PHAT survey area is
M yr with an average deprojected intensity of M yr kpc, which yields a total SFR of ~0.7
M yr when extrapolated to the entire area of M31's disk. This
SFR is consistent with measurements from broadband estimates. [abridged]Comment: 23 pages, 17 figures, 2 tables, accepted for publication in Ap
The Fundamental Planes of E+A galaxies and GALEX UV-excess early-type galaxies: Revealing their intimate connection
Strong Balmer absorption lines and the lack of Ha and [OII] emission lines
signify that E+As are post-starburst systems. Recent studies suggest that E+As
may undergo the transition from the `blue cloud' to the `red sequence' and
eventually migrate to red sequence ETGs. An observational validation of this
scenario is to identify the intervening galaxy population between E+As and the
red-sequence. Motivated by recent findings with GALEX that a large fraction of
ETGs exhibit UV-excess as a sign of RSF, we investigate the possible connection
of the UV-excess galaxies to E+As. In particular, we examine the FP scaling
relations of the largest sample of ~1,000 E+As selected from the SDSS and
~20,000 morphologically-selected SDSS ETGs with GALEX UV data. The FP
parameters, combined with stellar population indicators, reveal a certain group
of UV-excess ETGs that bridges between E+As and quiescent red galaxies. The
newly identified galaxies are the post-starburst systems characterized by
UV-excess but no Ha emission. This is a conceptual generalisation of "E+A", in
that the Balmer absorption line in the "E+A" definition is replaced with
UV-optical colours that are far more sensitive to RSF than the Balmer lines. We
refer to these UV-excess galaxies as "E+a" galaxies, which stands for
elliptical ("E") galaxies with a minority of A-type ("a") young stars. The
species are either (1) galaxies that experienced starbursts weaker than those
observed in E+As (1~10% of E+As, "mild E+As") or (2) the products of passively
evolved E+As after quenching star formation quite a while ago (~1 Gyr, "old
E+As"). We suggest that the latter type of E+a galaxies represents the most
recent arrival to the red sequence in the final phase of the "E+A" to "red
early-type" transition. (Abridged)Comment: 15 pages, 15 figures, Accepted for publication in MNRA
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