On the Evolution of the Velocity-Mass-Size Relations of Disk-Dominated Galaxies over the Past 10 Billion Years

We study the evolution of the scaling relations between maximum circular velocity, stellar mass and optical half-light radius of star-forming disk-dominated galaxies in the context of LCDM-based galaxy formation models. Using data from the literature combined with new data from the DEEP2 and AEGIS surveys we show that there is a consistent observational and theoretical picture for the evolution of these scaling relations from z\sim 2 to z=0. The evolution of the observed stellar scaling relations is weaker than that of the virial scaling relations of dark matter haloes, which can be reproduced, both qualitatively and quantitatively, with a simple, cosmologically-motivated model for disk evolution inside growing NFW dark matter haloes. In this model optical half-light radii are smaller, both at fixed stellar mass and maximum circular velocity, at higher redshifts. This model also predicts that the scaling relations between baryonic quantities evolve even more weakly than the corresponding stellar relations. We emphasize, though, that this weak evolution does not imply that individual galaxies evolve weakly. On the contrary, individual galaxies grow strongly in mass, size and velocity, but in such a way that they move largely along the scaling relations. Finally, recent observations have claimed surprisingly large sizes for a number of star-forming disk galaxies at z \sim 2, which has caused some authors to suggest that high redshift disk galaxies have abnormally high spin parameters. However, we argue that the disk scale lengths in question have been systematically overestimated by a factor \sim 2, and that there is an offset of a factor \sim 1.4 between H\alpha sizes and optical sizes. Taking these effects into account, there is no indication that star forming galaxies at high redshifts (z\sim 2) have abnormally high spin parameters.Comment: 19 pages, 10 figures, accepted to MNRAS, minor changes to previous versio

The DEEP Groth Strip Galaxy Redshift Survey. III. Redshift Catalog and Properties of Galaxies

The Deep Extragalactic Evolutionary Probe (DEEP) is a series of spectroscopic surveys of faint galaxies, targeted at the properties and clustering of galaxies at redshifts z ~ 1. We present the redshift catalog of the DEEP 1 GSS pilot phase of this project, a Keck/LRIS survey in the HST/WFPC2 Groth Survey Strip. The redshift catalog and data, including reduced spectra, are publicly available through a Web-accessible database. The catalog contains 658 secure galaxy redshifts with a median z=0.65, and shows large-scale structure walls to z = 1. We find a bimodal distribution in the galaxy color-magnitude diagram which persists to z = 1. A similar color division has been seen locally by the SDSS and to z ~ 1 by COMBO-17. For red galaxies, we find a reddening of only 0.11 mag from z ~ 0.8 to now, about half the color evolution measured by COMBO-17. We measure structural properties of the galaxies from the HST imaging, and find that the color division corresponds generally to a structural division. Most red galaxies, ~ 75%, are centrally concentrated, with a red bulge or spheroid, while blue galaxies usually have exponential profiles. However, there are two subclasses of red galaxies that are not bulge-dominated: edge-on disks and a second category which we term diffuse red galaxies (DIFRGs). The distant edge-on disks are similar in appearance and frequency to those at low redshift, but analogs of DIFRGs are rare among local red galaxies. DIFRGs have significant emission lines, indicating that they are reddened mainly by dust rather than age. The DIFRGs in our sample are all at z>0.64, suggesting that DIFRGs are more prevalent at high redshifts; they may be related to the dusty or irregular extremely red objects (EROs) beyond z>1.2 that have been found in deep K-selected surveys. (abridged)Comment: ApJ in press. 24 pages, 17 figures (12 color). The DEEP public database is available at http://saci.ucolick.org

The SPLASH Survey: Kinematics of Andromeda's Inner Spheroid

The combination of large size, high stellar density, high metallicity, and Sersic surface brightness profile of the spheroidal component of the Andromeda galaxy (M31) within R_proj ~ 20 kpc suggest that it is unlike any subcomponent of the Milky Way. In this work we capitalize on our proximity to and external view of M31 to probe the kinematical properties of this "inner spheroid." We employ a Markov chain Monte Carlo (MCMC) analysis of resolved stellar kinematics from Keck/DEIMOS spectra of 5651 red giant branch stars to disentangle M31's inner spheroid from its stellar disk. We measure the mean velocity and dispersion of the spheroid in each of five spatial bins after accounting for a locally cold stellar disk as well as the Giant Southern Stream and associated tidal debris. For the first time, we detect significant spheroid rotation (v_rot ~ 50 km/s) beyond R_proj ~ 5 kpc. The velocity dispersion decreases from about 140 km/s at R_proj = 7 kpc to 120 km/s at R_proj = 14 kpc, consistent to 2 sigma with existing measurements and models. We calculate the probability that a given star is a member of the spheroid and find that the spheroid has a significant presence throughout the spatial extent of our sample. Lastly, we show that the flattening of the spheroid is due to velocity anisotropy in addition to rotation. Though this suggests that the inner spheroid of M31 more closely resembles an elliptical galaxy than a typical spiral galaxy bulge, it should be cautioned that our measurements are much farther out (2 - 14 r_eff) than for the comparison samples.Comment: Accepted for publication in Ap

Discs in early-type lensing galaxies: effects on magnification ratios and measurements of H0H_0

Observations of early-type galaxies, both in the local universe and in clusters at medium redshifts, suggest that these galaxies often contain discs or disc-like structures. Using the results of Kelson et al. (2000) for the incidence of disc-components among the galaxies in the redshift z=0.33 cluster CL 1358+62, we investigate the effect of disc structures on the lensing properties of early-type galaxies. Statistical properties, like magnification cross sections and the expected number of quad (four-image) lens systems, are not affected greatly by the inclusion of discs that contain less than about 10 per cent of the total stellar mass. However, the properties of individual lens systems are affected. We estimate that 10-30 per cent of all quad lens systems, with early-type deflector galaxies, would be affected measurably by the presence of disc components. Intriguingly, the image magnification ratios are altered significantly. The amplitude of the predicted change is sufficient to explain the observed magnification ratios in systems like B1422+231 without requiring compact substructure. Furthermore, time delays between images also change; fitting a bulge-only model to early-type lenses that in fact contain a disc would yield a value of the Hubble constant H_0 that is systematically too low by about 25 per cent.Comment: Accepted for publication in MNRAS. 17 pages, 14 figures, 3 tables. Mainly minor changes to submitted version. Includes a more extended discussion on evidence of discs from light profile

Élaboration et validation d'un outil de mesure bref et modernisé de l'alliance thérapeutique : le Questionnaire Intégratif de l'Alliance Thérapeutique (QIAT)

Les questionnaires mesurant l’alliance thérapeutique utilisent des définitions variables pour opérationnaliser ce construit, reflet d’un manque de cohésion théorique, et plusieurs écueils concernant leur fiabilité et validité ont été identifiés (redondance conceptuelle avec la satisfaction des services, items moins pertinents dans les phases avancées des suivis, structures factorielles instables et effets plafond). Le Questionnaire Intégratif de l’Alliance Thérapeutique (QIAT) a été élaboré afin d’opérationnaliser une définition modernisée, intégrative et flexible de l’alliance thérapeutique et de pallier ces lacunes. Pour valider le QIAT, 223 canadiens francophones suivis pour des motifs reliés à la santé mentale ou au bien-être psychologique ont été recrutés par le biais de médias sociaux et de courriels institutionnels afin de remplir des questionnaires sur une plateforme web sécurisée. Un processus de sélection des meilleurs items à partir de la théorie classique des tests et de la théorie de réponse aux items (TRI), de l’analyse factorielle exploratoire et de plusieurs autres critères a mené à la création du QIAT-SG-10 (suivi global) et du QIAT-DS6 (dernière séance). Les deux versions du QIAT ont démontré des indices de cohérence interne nettement appréciables ainsi que des preuves solides de validité convergente, discriminante et concourante. La structure factorielle (deux facteurs corrélés) a également été confirmée. En comparaison au Session Rating Scale, le QIAT-DS-6 a démontré une meilleure fidélité en TRI, alors que le QIAT-SG-10 a présenté un effet plafond légèrement plus élevé que le Working Alliance Inventory – Short Revised (WAI-SR), mais il discrimine mieux l’alliance de la satisfaction des services. Malgré une certaine redondance avec le WAISR, le contenu des items du QIAT révèle des distinctions importantes (emphase sur les compétences affectives du thérapeute et sur les aspects de négociation, intégration du lien émotionnel relié au travail collaboratif et la pertinence des items peu importe les phases du suivi) justifiant son existence.Questionnaires measuring therapeutic alliance use various definitions to operationalize this construct, reflecting a lack of theoretical cohesion, and several pitfalls concerning their reliability and validity have been identified (conceptual redundancy with service satisfaction, less relevant items in the advanced phases of therapeutic process, unstable factor structures and ceiling effects). The Therapeutic Alliance Integrative Questionnaire (QIAT) was developed to operationalize a modernized, integrative, and flexible definition of therapeutic alliance and to address these shortcomings. To validate the QIAT, 223 French-speaking Canadians engaged in a therapeutic process for reasons related to mental health or psychological well-being were recruited through social media and institutional emails to complete questionnaires on a secure web platform. Selecting the best items based on classical test theory and item response theory (IRT), exploratory factor analysis, and several other criteria led to the creation of the QIAT-SG-10 (overall follow-up) and QIAT-DS-6 (last session). Both versions of the QIAT demonstrated appreciable indices of internal consistency as well as strong evidence of convergent, discriminant, and concurrent validity. The factor structure (two correlated factors) was also confirmed. In comparison to the Session Rating Scale, the QIAT-DS-6 demonstrated better reliability in IRT, while the QIAT-SG-10 showed a slightly higher ceiling effect than the Working Alliance Inventory - Short Revised (WAI-SR), but its discrimination from service satisfaction was higher. Despite a certain redundancy with the WAI-SR, the content of the QIAT items reveals important distinctions (emphasis on the emotional skills of the therapist and on aspects of negotiation, integration of the emotional bond specifically related to collaborative work, and the relevance of the items regardless of phases of therapeutic process) justifying its existence

Search for squarks and gluinos with the ATLAS detector in final states with jets and missing transverse momentum using √s=8 TeV proton-proton collision data

A search for squarks and gluinos in final states containing high-p T jets, missing transverse momentum and no electrons or muons is presented. The data were recorded in 2012 by the ATLAS experiment in s√=8 TeV proton-proton collisions at the Large Hadron Collider, with a total integrated luminosity of 20.3 fb−1. Results are interpreted in a variety of simplified and specific supersymmetry-breaking models assuming that R-parity is conserved and that the lightest neutralino is the lightest supersymmetric particle. An exclusion limit at the 95% confidence level on the mass of the gluino is set at 1330 GeV for a simplified model incorporating only a gluino and the lightest neutralino. For a simplified model involving the strong production of first- and second-generation squarks, squark masses below 850 GeV (440 GeV) are excluded for a massless lightest neutralino, assuming mass degenerate (single light-flavour) squarks. In mSUGRA/CMSSM models with tan β = 30, A 0 = −2m 0 and μ > 0, squarks and gluinos of equal mass are excluded for masses below 1700 GeV. Additional limits are set for non-universal Higgs mass models with gaugino mediation and for simplified models involving the pair production of gluinos, each decaying to a top squark and a top quark, with the top squark decaying to a charm quark and a neutralino. These limits extend the region of supersymmetric parameter space excluded by previous searches with the ATLAS detector

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Measurement of the production of a W boson in association with a charm quark in pp collisions at √s = 7 TeV with the ATLAS detector

The production of a W boson in association with a single charm quark is studied using 4.6 fb−1 of pp collision data at s√ = 7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96+0.26−0.30 at Q 2 = 1.9 GeV2, which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-section ratio σ(W + +c¯¯)/σ(W − + c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the s−s¯¯¯ quark asymmetry

Search for direct pair production of the top squark in all-hadronic final states in proton-proton collisions at s√=8 TeV with the ATLAS detector

The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of 20.1fb−1 of proton–proton collision data at √s = 8 TeV recorded with the ATLAS detector at the LHC are reported. The top squark is assumed to decay via t˜→tχ˜01 or t˜→ bχ˜±1 →bW(∗)χ˜01 , where χ˜01 (χ˜±1 ) denotes the lightest neutralino (chargino) in supersymmetric models. The search targets a fully-hadronic final state in events with four or more jets and large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits are reported in terms of the top squark and neutralino masses and as a function of the branching fraction of t˜ → tχ˜01 . For a branching fraction of 100%, top squark masses in the range 270–645 GeV are excluded for χ˜01 masses below 30 GeV. For a branching fraction of 50% to either t˜ → tχ˜01 or t˜ → bχ˜±1 , and assuming the χ˜±1 mass to be twice the χ˜01 mass, top squark masses in the range 250–550 GeV are excluded for χ˜01 masses below 60 GeV