57 research outputs found
Hoxb8 is required for normal grooming behavior in mice.
Journal ArticleRepertoires of grooming behaviors critical to survival are exhibited by most animal species, including humans. Genes that influence this complex behavior are unknown. We report that mice with disruptions of Hoxb8 show, with 100% penetrance, excessive grooming leading to hair removal and lesions. Additionally, these mice excessively groom normal cagemates. We have been unable to detect any skin or PNS abnormalities in Hoxb8 mutants. These observations suggest that the excessive, pathological grooming exhibited by these mice results from CNS abnormalities. Consistent with this interpretation, we demonstrate Hoxb8 expression in regions of the adult mouse CNS previously implicated in the control of grooming. The aberrant behavior observed in Hoxb8 mutants is not unlike that of humans suffering from the OC-spectrum disorder, trichotillomania. Interestingly, Hoxb8 is expressed in regions of the CNS known as the "OCD-circuit
Application of a Self-Similar Pressure Profile to Sunyaev-Zel'dovich Effect Data from Galaxy Clusters
We investigate the utility of a new, self-similar pressure profile for
fitting Sunyaev-Zel'dovich (SZ) effect observations of galaxy clusters. Current
SZ imaging instruments - such as the Sunyaev-Zel'dovich Array (SZA) - are
capable of probing clusters over a large range in physical scale. A model is
therefore required that can accurately describe a cluster's pressure profile
over a broad range of radii, from the core of the cluster out to a significant
fraction of the virial radius. In the analysis presented here, we fit a radial
pressure profile derived from simulations and detailed X-ray analysis of
relaxed clusters to SZA observations of three clusters with exceptionally high
quality X-ray data: A1835, A1914, and CL J1226.9+3332. From the joint analysis
of the SZ and X-ray data, we derive physical properties such as gas mass, total
mass, gas fraction and the intrinsic, integrated Compton y-parameter. We find
that parameters derived from the joint fit to the SZ and X-ray data agree well
with a detailed, independent X-ray-only analysis of the same clusters. In
particular, we find that, when combined with X-ray imaging data, this new
pressure profile yields an independent electron radial temperature profile that
is in good agreement with spectroscopic X-ray measurements.Comment: 28 pages, 6 figures, accepted by ApJ for publication (probably April
2009
CARMA Measurements of the Sunyaev-Zel'dovich Effect in RXJ1347.5-1145
We demonstrate the Sunyaev-Zel'dovich (SZ) effect imaging capabilities of the
Combined Array for Research in Millimeter-wave Astronomy (CARMA) by presenting
an SZ map of the galaxy cluster RXJ1347.5-1145. By combining data from multiple
CARMA bands and configurations, we are able to capture the structure of this
cluster over a wide range of angular scales, from its bulk properties to its
core morphology. We find that roughly 9% of this cluster's thermal energy is
associated with sub-arcminute-scale structure imparted by a merger,
illustrating the value of high-resolution SZ measurements for pursuing cluster
astrophysics and for understanding the scatter in SZ scaling relations. We also
find that the cluster's SZ signal is lower in amplitude than suggested by a
spherically-symmetric model derived from X-ray data, consistent with
compression along the line of sight relative to the plane of the sky. Finally,
we discuss the impact of upgrades currently in progress that will further
enhance CARMA's power as an SZ imaging instrument.Comment: 8 pages, 6 figure
Observations of High-Redshift X-Ray Selected Clusters with the Sunyaev-Zel'dovich Array
We report measurements of the Sunyaev-Zel'dovich (SZ) effect in three high-redshift (0.89 β€ z β€ 1.03), X-ray selected galaxy clusters. The observations were obtained at 30 GHz during the commissioning period of a new, eight-element interferometerβthe Sunyaev-Zel'dovich Array (SZA)βbuilt for dedicated SZ effect observations. The SZA observations are sensitive to angular scales larger than those subtended by the virial radii of the clusters. Assuming isothermality and hydrostatic equilibrium for the intracluster medium and gas-mass fractions consistent with those for clusters at moderate redshift, we calculate electron temperatures, gas masses, and total cluster masses from the SZ data. The SZ-derived masses, integrated approximately to the virial radii, are 1.9^(+0.5)_(-0.4) Γ 10^(14) M_β for Cl J1415.1+3612, 3.4^(+0.6)_(-0.5) Γ 10^(14) M_β for Cl J1429.0+4241, and 7.2^(+1.3)_(-0.9) Γ 10^(14) M_β for Cl J1226.9+3332. The SZ-derived quantities are in good agreement with the cluster properties derived from X-ray measurements
LoCuSS: A Comparison of Sunyaev-Zel'dovich Effect and Gravitational Lensing Measurements of Galaxy Clusters
We present the first measurement of the relationship between the
Sunyaev-Zel'dovich effect signal and the mass of galaxy clusters that uses
gravitational lensing to measure cluster mass, based on 14 X-ray luminous
clusters at z~0.2 from the Local Cluster Substructure Survey. We measure the
integrated Compton y-parameter, Y, and total projected mass of the clusters
(M_GL) within a projected clustercentric radius of 350 kpc, corresponding to
mean overdensities of 4000-8000 relative to the critical density. We find
self-similar scaling between M_GL and Y, with a scatter in mass at fixed Y of
32%. This scatter exceeds that predicted from numerical cluster simulations,
however, it is smaller than comparable measurements of the scatter in mass at
fixed T_X. We also find no evidence of segregation in Y between disturbed and
undisturbed clusters, as had been seen with T_X on the same physical scales. We
compare our scaling relation to the Bonamente et al. relation based on mass
measurements that assume hydrostatic equilibrium, finding no evidence for a
hydrostatic mass bias in cluster cores (M_GL = 0.98+/-0.13 M_HSE), consistent
with both predictions from numerical simulations and lensing/X-ray-based
measurements of mass-observable scaling relations at larger radii. Overall our
results suggest that the Sunyaev-Zel'dovich effect may be less sensitive than
X-ray observations to the details of cluster physics in cluster cores.Comment: Minor changes to match published version: 2009 ApJL 701:114-11
Joint analysis of X-ray and Sunyaev Zel'dovich observations of galaxy clusters using an analytic model of the intra-cluster medium
We perform a joint analysis of X-ray and Sunyaev Zel'dovich (SZ) effect data
using an analytic model that describes the gas properties of galaxy clusters.
The joint analysis allows the measurement of the cluster gas mass fraction
profile and Hubble constant independent of cosmological parameters. Weak
cosmological priors are used to calculate the overdensity radius within which
the gas mass fractions are reported. Such an analysis can provide direct
constraints on the evolution of the cluster gas mass fraction with redshift. We
validate the model and the joint analysis on high signal-to-noise data from the
Chandra X-ray Observatory and the Sunyaev-Zel'dovich Array for two clusters,
Abell 2631 and Abell 2204.Comment: ApJ in pres
LoCuSS: The Sunyaev-Zel'dovich Effect and Weak Lensing Mass Scaling Relation
We present the first weak-lensing-based scaling relation between galaxy
cluster mass, M_wl, and integrated Compton parameter Y_sph. Observations of 18
galaxy clusters at z~0.2 were obtained with the Subaru 8.2-m telescope and the
Sunyaev-Zel'dovich Array. The M_wl-Y_sph scaling relations, measured at
Delta=500, 1000, and 2500 rho_c, are consistent in slope and normalization with
previous results derived under the assumption of hydrostatic equilibrium (HSE).
We find an intrinsic scatter in M_wl at fixed Y_sph of 20%, larger than both
previous measurements of M_HSE-Y_sph scatter as well as the scatter in true
mass at fixed Y_sph found in simulations. Moreover, the scatter in our
lensing-based scaling relations is morphology dependent, with 30-40% larger
M_wl for undisturbed compared to disturbed clusters at the same Y_sph at r_500.
Further examination suggests that the segregation may be explained by the
inability of our spherical lens models to faithfully describe the
three-dimensional structure of the clusters, in particular, the structure along
the line-of-sight. We find that the ellipticity of the brightest cluster
galaxy, a proxy for halo orientation, correlates well with the offset in mass
from the mean scaling relation, which supports this picture. This provides
empirical evidence that line-of-sight projection effects are an important
systematic uncertainty in lensing-based scaling relations.Comment: Accepted versio
Comparison of Pressure Profiles of Massive Relaxed Galaxy Clusters using Sunyaev-Zel'dovich and X-ray Data
We present Sunyaev-Zel'dovich (SZ) effect observations of a sample of 25
massive relaxed galaxy clusters observed with the Sunyaev-Zel'dovich Array
(SZA), an 8-element interferometer that is part of the Combined Array for
Research in Millimeter-wave Astronomy (CARMA). We perform an analysis of new
SZA data and archival Chandra observations of this sample to investigate the
integrated pressure -- a proxy for cluster mass -- determined from X-ray and SZ
observations, two independent probes of the intra-cluster medium. This analysis
makes use of a model for the intra-cluster medium introduced by Bulbul (2010)
which can be applied simultaneously to SZ and X-ray data. With this model, we
estimate the pressure profile for each cluster using a joint analysis of the SZ
and X-ray data, and using the SZ data alone. We find that the integrated
pressures measured from X-ray and SZ data are consistent. This conclusion is in
agreement with recent results obtained using WMAP and Planck data, confirming
that SZ and X-ray observations of massive clusters detect the same amount of
thermal pressure from the intra-cluster medium. To test for possible biases
introduced by our choice of model, we also fit the SZ data using the universal
pressure profile proposed by Arnaud (2010), and find consistency between the
two models out to r500 in the pressure profiles and integrated pressures.Comment: Accepted for New Journal of Physics, Focus Issue on Galaxy Cluster
A Measurement of Arcminute Anisotropy in the Cosmic Microwave Background with the Sunyaev-Zel'dovich Array
We present 30 GHz measurements of the angular power spectrum of the cosmic
microwave background (CMB) obtained with the Sunyaev-Zel'dovich Array. The
measurements are sensitive to arcminute angular scales, where secondary
anisotropy from the Sunyaev-Zel'dovich effect (SZE) is expected to dominate.
For a broad bin centered at multipole 4066 we find 67+77-50 uK^2, of which
26+/-5 uK^2 is the expected contribution from primary CMB anisotropy and
80+/-54 uK^2 is the expected contribution from undetected radio sources. These
results imply an upper limit of 155 uK^2 (95% CL) on the secondary contribution
to the anisotropy in our maps. This level of SZE anisotropy power is consistent
with expectations based on recent determinations of the normalization of the
matter power spectrum, i.e., sigma_8~0.8.Comment: ApJ, 713, 82-89, (2010
Murine Dishevelled 3 Functions in Redundant Pathways with Dishevelled 1 and 2 in Normal Cardiac Outflow Tract, Cochlea, and Neural Tube Development
Dishevelled (Dvl) proteins are important signaling components of both the canonical Ξ²-catenin/Wnt pathway, which controls cell proliferation and patterning, and the planar cell polarity (PCP) pathway, which coordinates cell polarity within a sheet of cells and also directs convergent extension cell (CE) movements that produce narrowing and elongation of the tissue. Three mammalian Dvl genes have been identified and the developmental roles of Dvl1 and Dvl2 were previously determined. Here, we identify the functions of Dvl3 in development and provide evidence of functional redundancy among the three murine Dvls. Dvl3β/β mice died perinatally with cardiac outflow tract abnormalities, including double outlet right ventricle and persistent truncus arteriosis. These mutants also displayed a misorientated stereocilia in the organ of Corti, a phenotype that was enhanced with the additional loss of a single allele of the PCP component Vangl2/Ltap (LtapLp/+). Although neurulation appeared normal in both Dvl3β/β and LtapLp/+ mutants, Dvl3+/β;LtapLp/+ combined mutants displayed incomplete neural tube closure. Importantly, we show that many of the roles of Dvl3 are also shared by Dvl1 and Dvl2. More severe phenotypes were observed in Dvl3 mutants with the deficiency of another Dvl, and increasing Dvl dosage genetically with Dvl transgenes demonstrated the ability of Dvls to compensate for each other to enable normal development. Interestingly, global canonical Wnt signaling appeared largely unaffected in the double Dvl mutants, suggesting that low Dvl levels are sufficient for functional canonical Wnt signals. In summary, we demonstrate that Dvl3 is required for cardiac outflow tract development and describe its importance in the PCP pathway during neurulation and cochlea development. Finally, we establish several developmental processes in which the three Dvls are functionally redundant
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