Cosmology with photometric redshift surveys

We explore the utility of future photometric redshift imaging surveys for delineating the large-scale structure of the Universe, and assess the resulting constraints on the cosmological model. We perform two complementary types of analysis: (1) We quantify the statistical confidence and the accuracy with which such surveys will be able to detect and measure characteristic features in the clustering power spectrum such as the acoustic oscillations and the turnover, in a 'model-independent' fashion. We show for example that a 10,000 deg^2 imaging survey with depth r = 22.5 and photometric redshift accuracy dz/(1+z) = 0.03 will detect the acoustic oscillations with 99.9% confidence, measuring the associated preferred cosmological scale with 2% precision. Such a survey will also detect the turnover with 95% confidence, determining the corresponding scale with 20% accuracy. (2) By assuming a Lambda-CDM model power spectrum we calculate the confidence with which a non-zero baryon fraction can be deduced from such future galaxy surveys. We quantify 'wiggle detection' by calculating the number of standard deviations by which the baryon fraction is measured, after marginalizing over the shape parameter. This is typically a factor of four more significant (in terms of number of standard deviations) than the 'model-independent' result. We conclude that the precision with which the clustering pattern may be inferred from future photometric redshift surveys will be competitive with contemporaneous spectroscopic redshift surveys, assuming that systematic effects can be controlled. We also note that an analysis of Luminous Red Galaxies in the Sloan Digital Sky Survey may yield a marginal detection of acoustic oscillations in the imaging survey, in addition to that recently reported for the spectroscopic component.Comment: 23 pages, 22 figures, version accepted by MNRA

The War on Terrorism as State of Exception: A Challenge for Transnational Gender Theory

In this article, I explore the contributions of theoretical engagements of bare life and states of exception to gender theory in relation to the U.S.-led ‘war on terrorism,’ beginning in 2001. I discuss connections between the ongoing struggle over representations of the ‘Third World Woman,’ among feminists and the mainstream discourse that established the United States’ invasions of Afghanistan and Iraq and imprisonment of an extralegal class of ‘detainees’ as an inevitable, natural consequence of exceptional difference. In addition I highlight the responsibility academics, including feminist academics, to consider their own positions in relation to the economic, political and representational power dynamics they analyze

Cosmological baryonic and matter densities from 600,000 SDSS Luminous Red Galaxies with photometric redshifts

We analyze MegaZ-LRG, a photometric-redshift catalogue of Luminous Red Galaxies (LRGs) based on the imaging data of the Sloan Digital Sky Survey (SDSS) 4th Data Release. MegaZ-LRG, presented in a companion paper, contains 10^6 photometric redshifts derived with ANNz, an Artificial Neural Network method, constrained by a spectroscopic sub-sample of 13,000 galaxies obtained by the 2dF-SDSS LRG and Quasar (2SLAQ) survey. The catalogue spans the redshift range 0.4 < z < 0.7 with an r.m.s. redshift error ~ 0.03(1+z), covering 5,914 deg^2 to map out a total cosmic volume 2.5 h^-3 Gpc^3. In this study we use the most reliable 600,000 photometric redshifts to present the first cosmological parameter fits to galaxy angular power spectra from a photometric redshift survey. Combining the redshift slices with appropriate covariances, we determine best-fitting values for the matter and baryon densities of Omega_m h = 0.195 +/- 0.023 and Omega_b/Omega_m = 0.16 +/- 0.036 (with the Hubble parameter h = 0.75 and scalar index of primordial fluctuations n = 1 held fixed). These results are in agreement with and independent of the latest studies of the Cosmic Microwave Background radiation, and their precision is comparable to analyses of contemporary spectroscopic-redshift surveys. We perform an extensive series of tests which conclude that our power spectrum measurements are robust against potential systematic photometric errors in the catalogue. We conclude that photometric-redshift surveys are competitive with spectroscopic surveys for measuring cosmological parameters in the simplest vanilla models. Future deep imaging surveys have great potential for further improvement, provided that systematic errors can be controlled.Comment: 24 pages, 23 figures, MNRAS accepte

From Policy to Practice: Implementation of Georgia\u27s Medicaid Family Planning Waiver Program

From Policy to Practice: Implementation of Georgia’s Medicaid Family Planning Waiver Program Sarah C. Blake, MA 282 pages Directed by Dr. John Thomas The purpose of this research was to examine the implementation of Georgia’s Medicaid family planning program, known as Planning for Healthy Babies® or P4HB®. This program is the first such program to provide both family planning services and inter-pregnancy care services through a Medicaid expansion to low-income, uninsured women. An evaluative case study design was employed using mixed methods. These methods incorporated process measures to study the implementation of P4HB® and to assess whether P4HB® was implemented as planned We incorporated theory from the policy implementation and health care access literatures to understand what served as facilitators or barriers to successful implementation. Findings suggest that despite precise goals and objectives, formal guidance about the program did not incorporate clear implementation planning. Many stakeholders, including advocates, providers, and representatives from implementing agencies felt left out of the implementation process and did not feel invested in the program. Considerable confusion existed among eligible clients and providers about the nature and scope of the P4HB® program. This lack of awareness and understanding about P4HB® likely contributed to the program’s low enrollment and participation in the first year of its implementation. As many states prepare to expand their Medicaid programs under the Patient Protection and Affordable Care Act (ACA), this study provides important lessons for policy planning and implementation

You Taught Me Language: Using Shakespeare to Teach English to Speakers of Other Languages

This thesis explores how to use Shakespeare effectively in English language education. By considering cultural backgrounds and different translations, ESOL educators can assess what areas students need more guidance in, and how Shakespearean texts can help scaffold those areas. These texts can be used to teach grammar and mechanics as well as literary devices. The most effective teaching methods are also explored: examples of appropriate visuals, classroom activities, and discussion topics are given

Cosmology with the Square Kilometre Array

We argue that the Square Kilometre Array has the potential to make both redshift (HI) surveys and radio continuum surveys that will revolutionize cosmological studies, provided that it has sufficient instantaneous field-of-view that these surveys can cover a hemisphere in a timescale ~1 yr. Adopting this assumption, we focus on two key experiments which will yield fundamental new measurements in cosmology, characterizing the properties of the mysterious dark energy which dominates the dynamics of today's Universe. Experiment I will map out ~10^9 HI galaxies to redshift z~1.5, providing the premier measurement of the clustering power spectrum of galaxies: accurately delineating the acoustic oscillations and the `turnover'. Experiment II will quantify the cosmic shear distortion of ~10^10 radio continuum sources, determining a precise power spectrum of the dark matter, and its growth as a function of cosmic epoch. We contrast the performance of the SKA in precision cosmology with that of other facilities which will, probably or possibly, be available on a similar timescale. We conclude that data from the SKA will yield transformational science as the direct result of four key features: (i) the immense cosmic volumes probed, exceeding future optical redshift surveys by more than an order of magnitude; (ii) well-controlled systematic effects such as the narrow `k-space window function' for Experiment I and the accurately-known `point-spread function' for Experiment II; (iii) the ability to measure with high precision large-scale modes in the clustering power spectra, for which nuisance effects such as non-linear structure growth, peculiar velocities and `galaxy bias' are minimised; and (iv) different degeneracies between key parameters to those which are inherent in the CMB.Comment: 20 pages, 8 figures. To appear in "Science with the Square Kilometer Array", eds. C.Carilli and S.Rawlings, New Astronomy Reviews (Elsevier: Amsterdam