117 research outputs found
THE PRODUCTIVITY OF AGRICULTURAL RESEARCH AND EXTENSION EXPENDITURES IN THE SOUTHEAST
Research and Development/Tech Change/Emerging Technologies,
Large-scale Star Formation Triggering in the Low-mass Arp 82 System: A Nearby Example of Galaxy Downsizing Based on UV/Optical/Mid-IR Imaging
As part of our Spitzer Spirals, Bridges, and Tails project to help understand
the effects of galaxy interactions on star formation, we analyze GALEX
ultraviolet, SARA optical, and Spitzer infrared images of the interacting
galaxy pair Arp 82 (NGC 2535/6) and compare to a numerical simulation of the
interaction. We investigate the multiwavelength properties of several
individual star forming complexes (clumps). Using optical and UV colors,
EW(Halpha), and population synthesis models we constrain the ages of the clumps
and find that the median clump age is about 12 Myr. The clumps have masses
ranging from a few times 10^6 to 10^9 solar masses. In general, the clumps in
the tidal features have similar ages to those in the spiral region, but are
less massive. The 8 micron and 24 micron luminosities are used to estimate the
far-infrared luminosities and the star formation rates of the clumps. The total
clump star formation rate is 2.0+/-0.8 solar masses per year, while the entire
Arp 82 system is forming stars at a rate of 4.9+/-2.0 solar masses per year. We
find, for the first time, stars in the HI arc to the southeast of the NGC 2535
disk. Population synthesis models indicate that all of the observed populations
have young to intermediate ages. We conclude that although the gas disks and
some old stars may have formed early-on, the progenitors are late-type or low
surface brightness and the evolution of these galaxies was halted until the
recent encounter.Comment: Accepted for publication in the AJ, 22 Figures, 5 Table
Stochastic `Beads on a String' in the Accretion Tail of Arp 285
We present Spitzer infrared, GALEX UV, and SDSS and SARA optical images of
the peculiar interacting galaxy pair Arp 285 (NGC 2856/4), and compare with a
new numerical model of the interaction. We estimate the ages of clumps of star
formation in these galaxies using population synthesis models, carefully
considering the uncertainties on these ages. This system contains a striking
example of `beads on a string': a series of star formation complexes ~1 kpc
apart. These `beads' are found in a tail-like feature that is perpendicular to
the disk of NGC 2856, which implies that it was formed from material accreted
from the companion NGC 2854. The extreme blueness of the optical/UV colors and
redness of the mid-infrared colors implies very young stellar ages (~4 - 20
Myrs) for these star forming regions. Spectral decomposition of these `beads'
shows excess emission above the modeled stellar continuum in the 3.6 micron and
4.5 micron bands, indicating either contributions from interstellar matter to
these fluxes or a second older stellar population. These clumps have -12.0 <
M(B) < -10.6, thus they are less luminous than most dwarf galaxies. Our model
suggests that bridge material falling into the potential of the companion
overshoots the companion. The gas then piles up at apo-galacticon before
falling back onto the companion, and star formation occurs in the pile-up. A
luminous (M(B) ~ -13.6) extended (FWHM ~ 1.3 kpc) `bright spot' is visible at
the northwestern edge of the NGC 2856 disk, with an intermediate stellar
population (400 - 1500 Myrs). Our model suggests that this feature is part of a
expanding ripple-like `arc' created by an off-center ring-galaxy-like collision
between the two disks.Comment: Accepted by the Astronomical Journal. For color figures and appendix
material, go
tohttp://www.etsu.edu/physics/bsmith/research/sg/arp285/arp285.htm
Candidate Tidal Dwarf Galaxies in Arp 305: Lessons on Dwarf Detachment and Globular Cluster Formation
To search for Tidal Dwarf Galaxies (TDGs) and to study star formation in
tidal features, we are conducting a large UV imaging survey of interacting
galaxies selected from the Arp (1996) Atlas using the GALEX telescope. As part
of that study, we present a GALEX UV and SDSS and SARA optical study of the
gas-rich interacting galaxy pair Arp 305 (NGC 4016/7). The GALEX UV data reveal
much extended diffuse UV emission and star formation outside the disks. This
includes a luminous star forming region between the two galaxies, and a number
of such regions in tidal tails. We have identified 45 young star forming clumps
in Arp 305, including several TDG candidates. By comparing the UV and optical
colors to population synthesis models, we determined that the clumps are very
young, with several having ages of about 6 Myr. We do not find many
intermediate age clumps in spite of the fact that the last closest encounter
was about 300 Myr ago. We have used a smooth particle hydrodynamics code to
model the interaction and determine the fate of the star clusters and candidate
TDGs.Comment: 12 pages, 6 figures, and 5 tables. Accepted for publication in the
Astronomical Journa
Building social capital through breastfeeding peer support: Insights from an evaluation of a voluntary breastfeeding peer support service in North-West England
Background:
Peer support is reported to be a key method to help build social capital in communities. To date there are no studies that describe how this can be achieved through a breastfeeding peer support service. In this paper we present findings from an evaluation of a voluntary model of breastfeeding peer support in North-West England to describe how the service was operationalized and embedded into the community. This study was undertaken from May, 2012 to May, 2013.
Methods:
Interviews (group or individual) were held with 87 participants: 24 breastfeeding women, 13 peer supporters and 50 health and community professionals. The data contained within 23 monthly monitoring reports (January, 2011 to February 2013) compiled by the voluntary peer support service were also extracted and analysed.
Results:
Thematic analysis was undertaken using social capital concepts as a theoretical lens. Key findings were identified to resonate with âbondingâ, âbridgingâ and âlinkingâ forms of social capital. These insights illuminate how the peer support service facilitates âbondsâ with its members, and within and between women who access the service; how the service âbridgesâ with individuals from different interests and backgrounds, and how âlinksâ were forged with those in authority to gain access and reach to women and to promote a breastfeeding culture. Some of the tensions highlighted within the social capital literature were also identified.
Conclusions:
Horizontal and vertical relationships forged between the peer support service and community members enabled peer support to be embedded into care pathways, helped to promote positive attitudes to breastfeeding and to disseminate knowledge and maximise reach for breastfeeding support across the community. Further effort to engage with those of different ethnic backgrounds and to resolve tensions between peer supporters and health professionals is warranted
The KELT Follow-Up Network And Transit False-Positive Catalog: Pre-Vetted False Positives For TESS
The Kilodegree Extremely Little Telescope (KELT) project has been conducting a photometric survey of transiting planets orbiting bright stars for over 10 years. The KELT images have a pixel scale of ~23\u27\u27 pixelâ»Âčâvery similar to that of NASA\u27s Transiting Exoplanet Survey Satellite (TESS)âas well as a large point-spread function, and the KELT reduction pipeline uses a weighted photometric aperture with radius 3\u27. At this angular scale, multiple stars are typically blended in the photometric apertures. In order to identify false positives and confirm transiting exoplanets, we have assembled a follow-up network (KELT-FUN) to conduct imaging with spatial resolution, cadence, and photometric precision higher than the KELT telescopes, as well as spectroscopic observations of the candidate host stars. The KELT-FUN team has followed-up over 1600 planet candidates since 2011, resulting in more than 20 planet discoveries. Excluding ~450 false alarms of non-astrophysical origin (i.e., instrumental noise or systematics), we present an all-sky catalog of the 1128 bright stars (6 \u3c V \u3c 13) that show transit-like features in the KELT light curves, but which were subsequently determined to be astrophysical false positives (FPs) after photometric and/or spectroscopic follow-up observations. The KELT-FUN team continues to pursue KELT and other planet candidates and will eventually follow up certain classes of TESS candidates. The KELT FP catalog will help minimize the duplication of follow-up observations by current and future transit surveys such as TESS
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