2,934 research outputs found
A flux-ratio anomaly in the CO spectral line emission from gravitationally-lensed quasar MG J0414+0534
We present an analysis of archival observations with the Atacama Large
(sub-)Millimetre Array (ALMA) of the gravitationally lensed quasar MG
J0414+0534, which show four compact images of the quasar and an Einstein ring
from the dust associated with the quasar host galaxy. We confirm that the
flux-ratio anomalies observed in the mid-infrared and radio persists into the
sub-mm for the continuum images of the quasar. We report the detection of CO
(11-10) spectral line emission, which traces a region of compact gas around the
quasar nucleus. This line emission also shows evidence of a flux-ratio anomaly
between the merging lensed images that is consistent with those observed at
other wavelengths, suggesting high-excitation CO can also provide a useful
probe of substructures that is unaffected by microlensing or dust extinction.
However, we do not detect the candidate dusty dwarf galaxy that was previously
reported with this dataset, which we conclude is due to a noise artefact. Thus,
the cause of the flux-ratio anomaly between the merging lensed images is still
unknown. The composite compact and diffuse emission in this system suggest
lensed quasar-starbursts will make excellent targets for detecting dark
sub-haloes and testing models for dark matter.Comment: Accepted as MNRAS Lette
The final candidate from the JVAS/CLASS search for 6 arcsec to 15 arcsec image separation lensing
A search for 6 arcsec to 15 arcsec image separation lensing in the Jodrell
Bank-Very Large Array Astrometric Survey (JVAS) and the Cosmic Lens All-Sky
Survey (CLASS) by Phillips et al. found thirteen group and cluster
gravitational lens candidates. Through radio and optical imaging and
spectroscopy, Phillips et al. ruled out the lensing hypothesis for twelve of
the candidates. In this paper, new optical imaging and spectroscopy of
J0122+427, the final lens candidate from the JVAS/CLASS 6 arcsec to 15 arcsec
image separation lens search, are presented. This system is found not to be a
gravitational lens, but is just two radio-loud active galactic nuclei that are
separated by ~10 arcsec on the sky and are at different redshifts. Therefore,
it is concluded that there are no gravitational lenses in the JVAS and CLASS
surveys with image separations between 6 arcsec to 15 arcsec. This result is
consistent with the expectation that group- and cluster-scale dark matter
haloes are inefficient lenses due to their relatively flat inner density
profiles.Comment: 5 pages, 3 figures, 2 tables, accepted for publication in MNRA
A novel search for gravitationally lensed radio sources in wide-field VLBI imaging from the mJIVE-20 survey
We present a novel pilot search for gravitational lenses in the mJIVE-20
survey, which observed radio sources selected from FIRST with the
VLBA at an angular resolution of 5 mas. We have taken the visibility data for
an initial sources that were detected by the mJIVE-20 observations and
re-mapped them to make wide-field images, selecting fourteen sources that had
multiple components separated by mas, with a flux-ratio of
: and a surface brightness consistent with gravitational lensing.
Two of these candidates are re-discoveries of gravitational lenses found as
part of CLASS. The remaining twelve candidates were then re-observed at 1.4 GHz
and then simultaneously at 4.1 and 7.1 GHz with the VLBA to measure the
spectral index and surface brightness of the individual components as a
function of frequency. Ten were rejected as core-jet or core-hotspot(s)
systems, with surface brightness distributions and/or spectral indices
inconsistent with gravitational lensing, and one was rejected after lens
modelling demonstrated that the candidate lensed images failed the parity test.
The final lens candidate has an image configuration that is consistent with a
simple lens mass model, although further observations are required to confirm
the lensing nature. Given the two confirmed gravitational lenses in the
mJIVE-20 sample, we find a robust lensing-rate of :() for a
statistical sample of 635 radio sources detected on mas-scales, which is
consistent with that found for CLASS.Comment: 31 pages, 22 figures; accepted for publication in MNRA
Certificate Feeder Pig Program
The Iowa Certificate feeder pig program is a cooperative venture established in 1978 by the Iowa Veterinary Medical Association and the Iowa Pork Producers Association. The purposes are to 1) establish a set of health guidelines for feeder pigs; 2) identify feeder pig producers meeting or exceeding the guidelines; 3) encourage increased veterinary participation in the development and maintenance of herd health programs; and 4) supply feeder pig finishers with healthy quality pigs and information about he herd of origin, vaccination history, and products used prior to sale
Resolving on 100 pc scales the UV-continuum in Lyman- emitters between redshift 2 to 3 with gravitational lensing
We present a study of seventeen LAEs at redshift 23 gravitationally
lensed by massive early-type galaxies (ETGs) at a mean redshift of
approximately 0.5. Using a fully Bayesian grid-based technique, we model the
gravitational lens mass distributions with elliptical power-law profiles and
reconstruct the UV-continuum surface brightness distributions of the background
sources using pixellated source models. We find that the deflectors are close
to, but not consistent with isothermal models in almost all cases, at the
-level. We take advantage of the lensing magnification (typically
20) to characterise the physical and morphological properties of
these LAE galaxies. From reconstructing the ultra-violet continuum emission, we
find that the star-formation rates range from 0.3 to 8.5 M yr
and that the galaxies are typically composed of several compact and diffuse
components, separated by 0.4 to 4 kpc. Moreover, they have peak star-formation
rate intensities that range from 2.1 to 54.1 M yr kpc.
These galaxies tend to be extended with major axis ranging from 0.2 to 1.8 kpc
(median 561 pc), and with a median ellipticity of 0.49. This morphology is
consistent with disk-like structures of star-formation for more than half of
the sample. However, for at least two sources, we also find off-axis components
that may be associated with mergers. Resolved kinematical information will be
needed to confirm the disk-like nature and possible merger scenario for the
LAEs in the sample.Comment: 19 pages, 7 figures, accepted for publication on MNRA
ALMA imaging of SDP.81 - I. A pixelated reconstruction of the far-infrared continuum emission
We present a sub-50 pc-scale analysis of the gravitational lens system SDP.81
at redshift 3.042 using Atacama Large Millimetre/submillimetre Array (ALMA)
science verification data. We model both the mass distribution of the
gravitational lensing galaxy and the pixelated surface brightness distribution
of the background source using a novel Bayesian technique that fits the data
directly in visibility space. We find the 1 and 1.3 mm dust emission to be
magnified by a factor of u_tot = 17.6+/-0.4, giving an intrinsic total
star-formation rate of 315+/-60 M_sol/yr and a dust mass of 6.4+/-1.5*10^8
M_sol. The reconstructed dust emission is found to be non-uniform, but composed
of multiple regions that are heated by both diffuse and strongly clumped
star-formation. The highest surface brightness region is a ~1.9*0.7 kpc
disk-like structure, whose small extent is consistent with a potential
size-bias in gravitationally lensed starbursts. Although surrounded by extended
star formation, with a density of 20-30+/-10 M_sol/yr/kpc^2, the disk contains
three compact regions with densities that peak between 120-190+/-20
M_sol/yr/kpc^2. Such star-formation rate densities are below what is expected
for Eddington-limited star-formation by a radiation pressure supported
starburst. There is also a tentative variation in the spectral slope of the
different star-forming regions, which is likely due to a change in the dust
temperature and/or opacity across the source.Comment: MNRAS accepted 2015 April 1
Botanicals for Pigs—Garlic II
Botanicals have been proposed as a substitute for antimicrobials in swine diets because of potential natural antibacterial activity. Garlic (Allium sativam), a botanical that grows in Iowa, was compared with a standard antibacterial nursery dietary regimen. A trial conducted in 1997 had inclusion levels of 0.0, 0.5, 2.5 and 5%. These levels of garlic generally depressed feed intake and average daily gain in nursery pigs and depressed performance compared with the control diet with Mecadox. Muscle samples from the garlic-fed pigs all had “very objectionable” or “extremely objectionable” off-flavors.
This trial fed inclusion levels of 0.00, 0.10, 0.25, and 0.50% garlic, levels that hopefully would be low enough not to depress performance or alter meat flavors. Pigs fed diets without Mecadox demonstrated significantly poorer performance than with Mecadox inclusion. Based upon this and the 1997 studies at Iowa State University, pigs fed diets without Mecadox performed less well than those fed Mecadox. The addition of garlic did not enhance pig performance
Inclusion Body Rhinitis of Swine
Inclusion Body Rhinitis (IBR) is a viral disease of swine characterized by large basophilic intranuclear inclusion bodies in epithelial and reticular cells. It has been found in pigs in North American, Europe, Japan, Australia and Russia since it was first described in England by Done. The causative agent is a member of the herpes family of viruses and is classified as a cytomegalovirus
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