649 research outputs found
Constraining Scale-Dependent Non-Gaussianity with Future Large-Scale Structure and the CMB
We forecast combined future constraints from the cosmic microwave background
and large-scale structure on the models of primordial non-Gaussianity. We study
the generalized local model of non-Gaussianity, where the parameter f_NL is
promoted to a function of scale, and present the principal component analysis
applicable to an arbitrary form of f_NL(k). We emphasize the complementarity
between the CMB and LSS by using Planck, DES and BigBOSS surveys as examples,
forecast constraints on the power-law f_NL(k) model, and introduce the figure
of merit for measurements of scale-dependent non-Gaussianity.Comment: 28 pages, 8 figures, 2 tables; v2: references update
Direct dark matter detection around the corner? Prospects in the constrained MSSM
We outline the WIMP dark matter parameter space in the Constrained MSSM by performing a comprehensive statistical analysis that compares with experimental data predicted superpartner masses and other collider observables as well as a cold dark matter abundance. We find that 10.10 pbSI p10-8 pb for direct WIMP detection (with details slightly dependent on the assumptions made). We conclude that most of the 95% probability region for the cross section will be explored by future one-tonne detectors, that will therefore cover most of the currently favoured region of parameter space. \ua9 2007 IOP Publishing Ltd
Low Resolution Spectral Templates For AGNs and Galaxies From 0.03 -- 30 microns
We present a set of low resolution empirical SED templates for AGNs and
galaxies in the wavelength range from 0.03 to 30 microns based on the
multi-wavelength photometric observations of the NOAO Deep-Wide Field Survey
Bootes field and the spectroscopic observations of the AGN and Galaxy Evolution
Survey. Our training sample is comprised of 14448 galaxies in the redshift
range 0<~z<~1 and 5347 likely AGNs in the range 0<~z<~5.58. We use our
templates to determine photometric redshifts for galaxies and AGNs. While they
are relatively accurate for galaxies, their accuracies for AGNs are a strong
function of the luminosity ratio between the AGN and galaxy components.
Somewhat surprisingly, the relative luminosities of the AGN and its host are
well determined even when the photometric redshift is significantly in error.
We also use our templates to study the mid-IR AGN selection criteria developed
by Stern et al.(2005) and Lacy et al.(2004). We find that the Stern et
al.(2005) criteria suffers from significant incompleteness when there is a
strong host galaxy component and at z =~ 4.5, when the broad Halpha emission
line is redshifted into the [3.6] band, but that it is little contaminated by
low and intermediate redshift galaxies. The Lacy et al.(2004) criterion is not
affected by incompleteness at z =~ 4.5 and is somewhat less affected by strong
galaxy host components, but is heavily contaminated by low redshift star
forming galaxies. Finally, we use our templates to predict the color-color
distribution of sources in the upcoming WISE mission and define a color
criterion to select AGNs analogous to those developed for IRAC photometry. We
estimate that in between 640,000 and 1,700,000 AGNs will be identified by these
criteria, but will have serious completeness problems for z >~ 3.4.Comment: Accepted for publication in The Astrophysical Journal. 26 text pages
+ 3 tables + 20 figures, modified to include comments made by the referee.
Fortran codes, templates and electronic tables available at
http://www.astronomy.ohio-state.edu/~rjassef/lrt
Large non-Gaussian Halo Bias from Single Field Inflation
We calculate Large Scale Structure observables for non-Gaussianity arising
from non-Bunch-Davies initial states in single field inflation. These scenarios
can have substantial primordial non-Gaussianity from squeezed (but observable)
momentum configurations. They generate a term in the halo bias that may be more
strongly scale-dependent than the contribution from the local ansatz. We also
discuss theoretical considerations required to generate an observable
signature.Comment: 30 pages, 14 figures, typos corrected and minor changes to match
published version JCAP09(2012)00
Sex-Related Differences in Violence Exposure, Neural Reactivity to Threat, and Mental Health
The prefrontal cortex (PFC), hippocampus, and amygdala play an important role in emotional health. However, adverse life events (e.g., violence exposure) affect the function of these brain regions, which may lead to disorders such as depression and anxiety. Depression and anxiety disproportionately affect women compared to men, and this disparity may reflect sex differences in the neural processes that underlie emotion expression and regulation. The present study investigated sex differences in the relationship between violence exposure and the neural processes that underlie emotion regulation. In the present study, 200 participants completed a Pavlovian fear conditioning procedure in which cued and non-cued threats (i.e., unconditioned stimuli) were presented during functional magnetic resonance imaging. Violence exposure was previously assessed at four separate time points when participants were 11-19 years of age. Significant threat type (cued versus non-cued) × sex and sex × violence exposure interactions were observed. Specifically, women and men differed in amygdala and parahippocampal gyrus reactivity to cued versus non-cued threat. Further, dorsolateral PFC (dlPFC) and inferior parietal lobule (IPL) reactivity to threat varied positively with violence exposure among women, but not men. Similarly, threat-elicited skin conductance responses varied positively with violence exposure among women. Finally, women reported greater depression and anxiety symptoms than men. These findings suggest that sex differences in threat-related brain and psychophysiological activity may have implications for mental health
The catalog-to-cosmology framework for weak lensing and galaxy clustering for LSST
We present TXPipe, a modular, automated and reproducible pipeline for
ingesting catalog data and performing all the calculations required to obtain
quality-assured two-point measurements of lensing and clustering, and their
covariances, with the metadata necessary for parameter estimation. The pipeline
is developed within the Rubin Observatory Legacy Survey of Space and Time
(LSST) Dark Energy Science Collaboration (DESC), and designed for cosmology
analyses using LSST data. In this paper, we present the pipeline for the
so-called 3x2pt analysis -- a combination of three two-point functions that
measure the auto- and cross-correlation between galaxy density and shapes. We
perform the analysis both in real and harmonic space using TXPipe and other
LSST-DESC tools. We validate the pipeline using Gaussian simulations and show
that it accurately measures data vectors and recovers the input cosmology to
the accuracy level required for the first year of LSST data under this
simplified scenario. We also apply the pipeline to a realistic mock galaxy
sample extracted from the CosmoDC2 simulation suite (Korytov et al. 2019).
TXPipe establishes a baseline framework that can be built upon as the LSST
survey proceeds. Furthermore, the pipeline is designed to be easily extended to
science probes beyond the 3x2pt analysis.Comment: 20+11 pages, 10+11 figures. Version accepted in The Open Journal of
Astrophysic
Sensitivity and Insensitivity of Galaxy Cluster Surveys to New Physics
We study the implications and limitations of galaxy cluster surveys for
constraining models of particle physics and gravity beyond the Standard Model.
Flux limited cluster counts probe the history of large scale structure
formation in the universe, and as such provide useful constraints on
cosmological parameters. As a result of uncertainties in some aspects of
cluster dynamics, cluster surveys are currently more useful for analyzing
physics that would affect the formation of structure than physics that would
modify the appearance of clusters. As an example we consider the Lambda-CDM
cosmology and dimming mechanisms, such as photon-axion mixing.Comment: 24 pages, 8 eps figures. References added, discussion of scatter in
relations between cluster observables lengthene
A Joint Roman Space Telescope and Rubin Observatory Synthetic Wide-Field Imaging Survey
We present and validate 20 deg of overlapping synthetic imaging surveys
representing the full depth of the Nancy Grace Roman Space Telescope
High-Latitude Imaging Survey (HLIS) and five years of observations of the Vera
C. Rubin Observatory Legacy Survey of Space and Time (LSST). The two synthetic
surveys are summarized, with reference to the existing 300 deg of LSST
simulated imaging produced as part of Dark Energy Science Collaboration (DESC)
Data Challenge 2 (DC2). Both synthetic surveys observe the same simulated DESC
DC2 universe. For the synthetic Roman survey, we simulate for the first time
fully chromatic images along with the detailed physics of the Sensor Chip
Assemblies derived from lab measurements using the flight detectors. The
simulated imaging and resulting pixel-level measurements of photometric
properties of objects span a wavelength range of 0.3 to 2.0 m. We
also describe updates to the Roman simulation pipeline, changes in how
astrophysical objects are simulated relative to the original DC2 simulations,
and the resulting simulated Roman data products. We use these simulations to
explore the relative fraction of unrecognized blends in LSST images, finding
that 20-30% of objects identified in LSST images with -band magnitudes
brighter than 25 can be identified as multiple objects in Roman images. These
simulations provide a unique testing ground for the development and validation
of joint pixel-level analysis techniques of ground- and space-based imaging
data sets in the second half of the 2020s -- in particular the case of joint
Roman--LSST analyses
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