Morphology in the Era of Large Surveys

The study of galaxies has changed dramatically over the past few decades with the advent of large-scale astronomical surveys. These large collaborative efforts have made available high-quality imaging and spectroscopy of hundreds of thousands of systems, providing a body of observations which has significantly enhanced our understanding not only of cosmology and large-scale structure in the universe but also of the astrophysics of galaxy formation and evolution. Throughout these changes, one thing that has remained constant is the role of galaxy morphology as a clue to understanding galaxies. But obtaining morphologies for large numbers of galaxies is challenging; this topic, "Morphology in the era of large surveys", was the subject of a recent discussion meeting at the Royal Astronomical Society, and this "Astronomy and Geophysics" article is a report on that meeting.Comment: Meeting Report article published in the October 2013 issue of the Royal Astronomical Society journal Astronomy and Geophysics. 4 page pdf with colour image

Moderate-Luminosity Growing Black Holes From 1.25 < z < 2.7: Varied Accretion In Disk-Dominated Hosts

We compute black hole masses and bolometric luminosities for 57 active galactic nuclei (AGN) in the redshift range 1.25 < z < 2.67, selected from the GOODS-South deep multi-wavelength survey field via their X-ray emission. We determine host galaxy morphological parameters by separating the galaxies from their central point sources in deep HST images, and host stellar masses and colors by multi-wavelength SED fitting. 90% of GOODS AGN at these redshifts have detected rest-frame optical nuclear point sources; bolometric luminosities range from 2e43 - 2e46 erg/s. The black holes are growing at a range of accretion rates, with at least 50% of the sample having L/L_Edd < 0.1. 70% of host galaxies have stellar masses M* > 1e10 M_sun, with a range of colors suggesting a complex star formation history. We find no evolution of AGN bolometric luminosity within the sample, and no correlation between AGN bolometric luminosity and host stellar mass, color or morphology. Fully half the sample of host galaxies is disk-dominated, with another 25% having strong disk components. Fewer than 15% of the systems appear to be at some stage of a major merger. These moderate-luminosity AGN hosts are therefore inconsistent with a dynamical history dominated by mergers strong enough to destroy disks, indicating minor mergers or secular processes dominate the co-evolution of galaxies and their central black holes at z ~ 2.Comment: 11 pages, 6 figures, accepted to ApJ. Sersic indices, AGN/galaxy luminosity ratios, stellar masses etc. provided in Table

Major Mergers Host the Most Luminous Red Quasars at z ~ 2: A Hubble Space Telescope WFC3/IR Study

We used the Hubble Space Telescope WFC3 near-infrared camera to image the host galaxies of a sample of eleven luminous, dust-reddened quasars at z ~ 2 -- the peak epoch of black hole growth and star formation in the Universe -- to test the merger-driven picture for the co-evolution of galaxies and their nuclear black holes. The red quasars come from the FIRST+2MASS red quasar survey and a newer, deeper, UKIDSS+FIRST sample. These dust-reddened quasars are the most intrinsically luminous quasars in the Universe at all redshifts, and may represent the dust-clearing transitional phase in the merger-driven black hole growth scenario. Probing the host galaxies in rest-frame visible light, the HST images reveal that 8/10 of these quasars have actively merging hosts, while one source is reddened by an intervening lower redshift galaxy along the line-of-sight. We study the morphological properties of the quasar hosts using parametric Sersic fits as well as the non-parametric estimators (Gini coefficient, M_{20} and asymmetry). Their properties are heterogeneous but broadly consistent with the most extreme morphologies of local merging systems such as Ultraluminous Infrared galaxies. The red quasars have a luminosity range of log(L_bol) = 47.8 - 48.3 (erg/s) and the merger fraction of their AGN hosts is consistent with merger-driven models of luminous AGN activity at z=2, which supports the picture in which luminous quasars and galaxies co-evolve through major mergers that trigger both star formation and black hole growth.Comment: Submitted to ApJ. This version includes the response to the referee repor

Perceptual Differentiation of African American and European American Children Based on Gender and Ethnicity of Listeners

Thomas and Reaser (2004) demonstrated that adult speakers can be perceptually differentiated by listeners with respect to gender and ethnicity. They presented data from various studies with respect to adult speakers, but no data for child speakers. It follows that there are cues in the acoustic signal that support making distinctions amongst adult speakers. Following the onset of puberty, these acoustic parameters begin to emerge, enabling listeners to reliably identify speaker characteristics in adulthood (Berger, 2008). The question remains, at what point across the pubertal transition does perceptual accuracy meet the level for adult speakers? The goal of our research is to examine how the gender and ethnicity of the listener affects the accuracy with which they are able to identify these same aspects of a child speaker. Undergraduate students completed a language background questionnaire and then listened to audio recordings of European American and African American children producing /h-vowel-d/ words and sentences. The participants listened to four blocks of recordings: forward words, reverse words, forward sentences, and reverse sentences, containing items spoken by children of each ethnicity, age, and gender. The listeners identified which ethnicity and gender they believed the speaker to be, as well as how confident they were of their choice. We expect that minority (African American, Hispanic, Native American, Pacific Islander, and Asian American) and female participants will have greater accuracy for all speakers. We also anticipate that accuracy of identification will improve as the age of the speaker increases due to the changing of the voice as a result of puberty. The study will provide greater knowledge of how the age of a child speaker impacts the ability of the listener to identify the speaker’s gender and ethnicity. The implications can be informative for individuals who work with children and in speech-related professions

Fidelity protocol for the Action Success Knowledge (ASK) trial: A psychosocial intervention administered by speech and language therapists to prevent depression in people with post-stroke aphasia

Introduction: Treatment fidelity is a complex, multifaceted evaluative process which refers to whether a studied intervention was delivered as intended. Monitoring and enhancing fidelity is one recommendation of the TiDIER (Template for Intervention Description and Replication) checklist, as fidelity can inform interpretation and conclusions drawn about treatment effects. Despite the methodological and translational benefits, fidelity strategies have been used inconsistently within health behaviour intervention studies; in particular, within aphasia intervention studies, reporting of fidelity remains relatively rare. This paper describes the development of a fidelity protocol for the Action Success Knowledge (ASK) study, a current cluster randomised trial investigating an early mood intervention for people with aphasia (a language disability caused by stroke). Methods and analysis: A novel fidelity protocol and tool was developed to monitor and enhance fidelity within the two arms (experimental treatment and attention control) of the ASK study. The ASK fidelity protocol was developed based on the National Institutes of Health Behaviour Change Consortium fidelity framework. Ethics and dissemination: The study protocol was approved by the Darling Downs Hospital and Health Service Human Research Ethics Committee in Queensland, Australia under the National Mutual Acceptance scheme of multicentre human research projects. Specific ethics approval was obtained for those participating sites who were not under the National Mutual Agreement at the time of application. The monitoring and ongoing conduct of the research project is in line with requirements under the National Mutual Acceptance. On completion of the trial, findings from the fidelity reviews will be disseminated via publications and conference presentations. Trial registration number ACTRN12614000979651