1,967 research outputs found
A New Hybrid Framework to Efficiently Model Lines of Sight to Gravitational Lenses
In strong gravitational lens systems, the light bending is usually dominated
by one main galaxy, but may be affected by other mass along the line of sight
(LOS). Shear and convergence can be used to approximate the contributions from
less significant perturbers (e.g. those that are projected far from the lens or
have a small mass), but higher order effects need to be included for objects
that are closer or more massive. We develop a framework for multiplane lensing
that can handle an arbitrary combination of tidal planes treated with shear and
convergence and planes treated exactly (i.e., including higher order terms).
This framework addresses all of the traditional lensing observables including
image positions, fluxes, and time delays to facilitate lens modelling that
includes the non-linear effects due to mass along the LOS. It balances accuracy
(accounting for higher-order terms when necessary) with efficiency (compressing
all other LOS effects into a set of matrices that can be calculated up front
and cached for lens modelling). We identify a generalized multiplane mass sheet
degeneracy, in which the effective shear and convergence are sums over the
lensing planes with specific, redshift-dependent weighting factors.Comment: 13 pages, 2 figure
Optimal Mass Configurations for Lensing High-Redshift Galaxies
We investigate the gravitational lensing properties of lines of sight
containing multiple cluster-scale halos, motivated by their ability to lens
very high-redshift (z ~ 10) sources into detectability. We control for the
total mass along the line of sight, isolating the effects of distributing the
mass among multiple halos and of varying the physical properties of the halos.
Our results show that multiple-halo lines of sight can increase the magnified
source-plane region compared to the single cluster lenses typically targeted
for lensing studies, and thus are generally better fields for detecting very
high-redshift sources. The configurations that result in optimal lensing cross
sections benefit from interactions between the lens potentials of the halos
when they overlap somewhat on the sky, creating regions of high magnification
in the source plane not present when the halos are considered individually. The
effect of these interactions on the lensing cross section can even be
comparable to changing the total mass of the lens from 10^15 M_sun to 3x10^15
M_sun. The gain in lensing cross section increases as the mass is split into
more halos, provided that the lens potentials are projected close enough to
interact with each other. A nonzero projected halo angular separation, equal
halo mass ratio, and high projected halo concentration are the best mass
configurations, whereas projected halo ellipticity, halo triaxiality, and the
relative orientations of the halos are less important. Such high mass,
multiple-halo lines of sight exist in the SDSS.Comment: Accepted for publication in ApJ; emulateapj format; 24 pages, 13
figures, 1 table; plots updated to reflect erratu
In vivo imaging of protease activity by Probody therapeutic activation.
Probody™ therapeutics are recombinant, proteolytically-activated antibody prodrugs, engineered to remain inert until activated locally by tumor-associated proteases. Probody therapeutics exploit the fundamental dysregulation of extracellular protease activity that exists in tumors relative to healthy tissue. Leveraging the ability of a Probody therapeutic to bind its target at the site of disease after proteolytic cleavage, we developed a novel method for profiling protease activity in living animals. Using NIR optical imaging, we demonstrated that a non-labeled anti-EGFR Probody therapeutic can become activated and compete for binding to tumor cells in vivo with a labeled anti-EGFR monoclonal antibody. Furthermore, by inhibiting matriptase activity in vivo with a blocking-matriptase antibody, we show that the ability of the Probody therapeutic to bind EGFR in vivo was dependent on protease activity. These results demonstrate that in vivo imaging of Probody therapeutic activation can be used for screening and characterization of protease activity in living animals, and provide a method that avoids some of the limitations of prior methods. This approach can improve our understanding of the activity of proteases in disease models and help to develop efficient strategies for cancer diagnosis and treatment
Hoxa11 regulates stromal cell death and proliferation during neonatal uterine development
Journal ArticleIncreasing evidence indicates that the Hoxa11 gene plays a critical role in the proper development of the uterus. In this report, we describe potential altered cellular processes in the developing uterus of Hoxa11 mutants. Histologic analysis demonstrates normal uterine morphology in Hoxa11 mutants as compared with controls at the newborn stage and d 7 after birth. Stromal tissue was moderately reduced in the Hoxa11 mutant uterus by d14 after birth and was absent by d 21 after birth. There is decreased cellular proliferation in the Hoxa11 mutant uterus both at 7 and 14 d after birth. Terminal deoxyribonucleotide transferase-mediated deoxyuridine triphosphate nick-end labeling analysis demonstrates that apoptosis was markedly increased in the Hoxa11 mutant uterus at d 14 after birth. p27 is decreased in the Hoxa11 mutant as evidenced by real-time PCR. Epidermal growth factor receptor expression is dramatically decreased as evidenced by both real-time PCR and immunohistochemistry results. These findings suggest that Hoxa11 is required for proper cellular proliferation and apoptotic responses in the developing neonatal uterus and that the regulation of epidermal growth factor receptor is critical to these processes. (Molecular Endocrinology 18:184-193, 2004
Joint Strong and Weak Lensing Analysis of the Massive Cluster Field J0850+3604
We present a combined strong and weak lensing analysis of the
J085007.6+360428 (J0850) field, which was selected by its high projected
concentration of luminous red galaxies and contains the massive cluster Zwicky
1953. Using Subaru/Suprime-Cam imaging and
MMT/Hectospec spectroscopy, we first perform a weak lensing shear analysis to
constrain the mass distribution in this field, including the cluster at and a smaller foreground halo at . We then add a strong
lensing constraint from a multiply-imaged galaxy in the imaging data with a
photometric redshift of . Unlike previous cluster-scale lens
analyses, our technique accounts for the full three-dimensional mass structure
in the beam, including galaxies along the line of sight. In contrast with past
cluster analyses that use only lensed image positions as constraints, we use
the full surface brightness distribution of the images. This method predicts
that the source galaxy crosses a lensing caustic such that one image is a
highly-magnified "fold arc", which could be used to probe the source galaxy's
structure at ultra-high spatial resolution ( pc). We calculate the mass
of the primary cluster to be with a concentration of , consistent with the mass-concentration relation of
massive clusters at a similar redshift. The large mass of this cluster makes
J0850 an excellent field for leveraging lensing magnification to search for
high-redshift galaxies, competitive with and complementary to that of
well-studied clusters such as the HST Frontier Fields.Comment: Accepted for publication in The Astrophysical Journal; 14 pages, 13
figures, 3 table
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Shear-Wave Velocity Characterization of the USGS Hawaiian Strong-Motion Network on the Island of Hawaii and Development of an NEHRP Site-Class Map
To assess the level and nature of ground shaking in Hawaii for the purposes of earthquake hazard mitigation and seismic design, empirical ground-motion prediction models are desired. To develop such empirical relationships, knowledge of the subsurface site conditions beneath strong-motion stations is critical. Thus, as a first step to develop ground-motion prediction models for Hawaii, wspectral-analysis-of-surface-waves (SASW) profiling was performed at the 22 free-field U.S. Geological Survey (USGS) strong-motion sites on the Big Island to obtain shear-wave velocity (V(S)) data. Nineteen of these stations recorded the 2006 Kiholo Bay moment magnitude (M) 6.7 earthquake, and 17 stations recorded the triggered M 6.0 Mahukona earthquake. V(S) profiling was performed to reach depths of more than 100 ft. Most of the USGS stations are situated on sites underlain by basalt, based on surficial geologic maps. However, the sites have varying degrees of weathering and soil development. The remaining strong-motion stations are located on alluvium or volcanic ash. V(S30) (average V(S) in the top 30 m) values for the stations on basalt ranged from 906 to 1908 ft/s [National Earthquake Hazards Reduction Program (NEHRP) site classes C and D], because most sites were covered with soil of variable thickness. Based on these data, an NEHRP site-class map was developed for the Big Island. These new V(S) data will be a significant input into an update of the USGS statewide hazard maps and to the operation of ShakeMap on the island of Hawaii.George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) under NSF CMS-0086605FEMA HSFEHQ-06-D-0162, HSFEHQ-04-D-0733U.S. Geological Survey, Department of the Interior 08HQGR0036Geotechnical Engineering Cente
A Spectroscopic Survey of the Fields of 28 Strong Gravitational Lenses: Implications for
Strong gravitational lensing provides an independent measurement of the
Hubble parameter (). One remaining systematic is a bias from the
additional mass due to a galaxy group at the lens redshift or along the
sightline. We quantify this bias for more than 20 strong lenses that have
well-sampled sightline mass distributions, focusing on the convergence
and shear . In 23% of these fields, a lens group contributes a 1%
convergence bias; in 57%, there is a similarly significant line-of-sight group.
For the nine time delay lens systems, is overestimated by 11%
on average when groups are ignored. In 67% of fields with total
0.01, line-of-sight groups contribute more convergence than
do lens groups, indicating that the lens group is not the only important mass.
Lens environment affects the ratio of four (quad) to two (double) image
systems; all seven quads have lens groups while only three of 10 doubles do,
and the highest convergences due to lens groups are in quads. We calibrate the
- relation: with a rms scatter of 0.34 dex.
Shear, which, unlike convergence, can be measured directly from lensed images,
can be a poor predictor of ; for 19% of our fields, is
. Thus, accurate cosmology using strong gravitational lenses
requires precise measurement and correction for all significant structures in
each lens field.Comment: 34 pages, 11 figures, accepted for publication in Ap
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