The Sloan Lens ACS Survey. IX. Colors, Lensing and Stellar Masses of Early-type Galaxies

We present the current photometric dataset for the Sloan Lens ACS (SLACS) Survey, including HST photometry from ACS, WFPC2, and NICMOS. These data have enabled the confirmation of an additional 15 grade `A' (certain) lens systems, bringing the number of SLACS grade `A' lenses to 85; including 13 grade `B' (likely) systems, SLACS has identified nearly 100 lenses and lens candidates. Approximately 80% of the grade `A' systems have elliptical morphologies while ~10% show spiral structure; the remaining lenses have lenticular morphologies. Spectroscopic redshifts for the lens and source are available for every system, making SLACS the largest homogeneous dataset of galaxy-scale lenses to date. We have developed a novel Bayesian stellar population analysis code to determine robust stellar masses with accurate error estimates. We apply this code to deep, high-resolution HST imaging and determine stellar masses with typical statistical errors of 0.1 dex; we find that these stellar masses are unbiased compared to estimates obtained using SDSS photometry, provided that informative priors are used. The stellar masses range from 10^10.5 to 10^11.8 M$_\odot$ and the typical stellar mass fraction within the Einstein radius is 0.4, assuming a Chabrier IMF. The ensemble properties of the SLACS lens galaxies, e.g. stellar masses and projected ellipticities, appear to be indistinguishable from other SDSS galaxies with similar stellar velocity dispersions. This further supports that SLACS lenses are representative of the overall population of massive early-type galaxies with M* >~ 10^11 M$_\odot$, and are therefore an ideal dataset to investigate the kpc-scale distribution of luminous and dark matter in galaxies out to z ~ 0.5.Comment: 20 pages, 18 figures, 5 tables, published in Ap

Beyond deficiency:Potential benefits of increased intakesof vitamin K for bone and vascular health

Vitamin K is wellknown for its role in the synthesisof a number of blood coagulationfactors.During recent years vitaminK-dependent proteins werediscovered to be of vital importancefor bone and vascular health.Recommendations for dietary vitaminK intake have been made onthe basis of the hepatic requirementsfor the synthesis of bloodcoagulation factors.Accumulatingevidence suggests that the requirementsfor other functions thanblood coagulation may be higher.This paper is the result of a closedworkshop (Paris,November 2002)in which a number of Europeanvitamin K experts reviewed theavailable data and formulated theirstandpoint with respect to recommendeddietary vitamin K intakeand the use of vitamin K-containingsupplements

‘Jugglers’, ‘copers’ and ‘strugglers’: academics’ perceptions of being a head of department in a post-1992 UK university and how it influences their future careers

This study investigates the experiences of academics who became department heads in a post-1992 UK university and explores the influence that being in the position has on their planned future academic career. Drawing on life history interviews undertaken with 17 male and female heads of department, the paper constitutes an in-depth study of their careers in the same university. The findings suggest that academics who become department heads not only need the capacity to assume a range of personal and professional identities, but need flexibility to regularly adopt and switch between them. Whether individuals can successfully balance and manage such multiple identities, or whether they experience major conflicts within or between them, greatly affects their experiences of being a head of department and seems to influence their subsequent career decisions. The paper concludes by proposing a conceptual framework and typology to interpret the career trajectories of academics that became department heads in the case university

The Sloan Lens ACS Survey. VIII. The relation between environment and internal structure of early-type galaxies

We study the relation between the internal structure of early-type galaxies and their environment using 70 strong gravitational lenses from the Sloan ACS Lens Survey. The Sloan database is used to determine two measures of overdensity of galaxies around each lens: the projected number density of galaxies inside the tenth nearest neighbor (\Sigma_{10}) and within a cone of radius one h^{-1} Mpc (D_1). Our main results are: 1) The average overdensity is somewhat larger than unity, consistent with lenses preferring overdense environments as expected for massive early-type galaxies (12/70 lenses are in known groups/clusters). 2) The distribution of overdensities is indistinguishable from that of "twin" non-lens galaxies selected from SDSS to have the same redshift and stellar velocity dispersion \sigma_*. Thus, within our errors, lens galaxies are an unbiased population, and the SLACS results can be generalized to the overall population of early-type galaxies. 3) Typical contributions from external mass distribution are no more than a few per cent, reaching 10-20% (~0.05-0.10 external convergence) only in the most extreme overdensities. 4) No significant correlation between overdensity and slope of the mass density profile of the lens is found. 5) Satellite galaxies (those with a more luminous companion) have marginally steeper mass density profiles than central galaxies (those without). This result suggests that tidal stripping may affect the mass structure of early-type galaxies down to kpc scales probed by strong lensing, when they fall into larger structures [ABRIDGED].Comment: ApJ, in press; minor changes with respect to v

The seaweeds of Kenya: Checklist, history of seaweed study, coastal environment, and analysis of seaweed diversity and biogeography

The seaweeds of Kenya are relatively well documented in comparison with the marine floras of other countries in the Indian Ocean. A checklist is provided of the seaweeds recorded, which includes a total of 386 species (214 red algae, 116 green algae and 56 brown algae), plus an additional 19 infra-specific taxa. This is the first detailed list for almost 30 years, with a 29% increase in species compared to the previous listing. The history of seaweed study in Kenya and the Kenyan coastal environment as a habitat for seaweeds are discussed in detail. An ordination analysis of the global biogeographic relationships of the Kenyan seaweed flora shows clearly the internal consistency of the Indo-Pacific seaweed flora at this large scale. Data on Indian Ocean relationships show that the Kenyan flora produces a distinct grouping of seaweed floras from Tanzania, Madagascar, Mozambique and the Indian Ocean coast of South Africa, which is somewhat separated from the floras of the rest of the Indian Ocean. The data reveal that Mozambiquan seaweeds are seriously understudied, with only 26% of the Kenyan flora having been recorded in that country, compared with 68% in Tanzania, 41% in Madagascar, and 43% in South Africa

Feasibility and acceptability of postpartum voluntary counselling and testing (PPVCT) in a large tertiary hospital in the South African setting

Objective. To demonstrate the feasibility and acceptability of introducing postpartum voluntary counselling and testing (PPVCT) and the provision of post-exposure nevirapine prophylaxis (PEP) to HIV-exposed infants whose mothers did not receive any antiretroviral prophylaxis to prevent mother-to-child transmission (PMTCT) in a large, tertiary hospital in the South African setting. Design. Observational, interventional study. Setting. The programme was implemented at Chris Hani Baragwanath Hospital (tertiary referral centre) in Soweto, South Africa, following a study that established the efficacy of a postpartum regimen of PEP in PMTCT. Participants. From January 2003 to December 2004, 7 500 women who delivered at Chris Hani Baragwanath Hospital without a documented HIV-1 result were identified in the postnatal wards. PPVCT was offered to all eligible participants. Intervention. On-site HIV rapid tests were performed on all women who agreed to testing. For those women testing HIV-1 positive, a single dose of nevirapine syrup was offered to their infants as PEP within 72 hours after delivery. Infant feeding counselling, assistance with follow-up care and support programmes were also offered. Main outcome. From January 2003 to December 2004, 34 776 deliveries occurred at Chris Hani Baragwanath Hospital. Of these, 7 500 (21.5%) had no documented HIV status. After delivery 5 751 (76.7%) women were offered VCT, and of these 3 794 (66%) accepted testing. Of these women, 1 294 (34%) tested HIV positive and 1 243 (96%) women accepted the administration of single-dose nevirapine to their infants. Conclusions. The uptake of PPVCT is comparable to that seen in established antenatal VCT despite the numerous challenges PPVCT presents. This suggests that PPVCT is both an acceptable and a feasible option in a busy, resource-limited setting and remains an important strategy in PMTCT in untreated individuals. Southern African Journal of HIV Medicine Vol. 6 (2) 2005: pp. 8-1

Radio-Luminous Southern Seyfert Galaxies. I. Radio Images and Selected Optical/Near-Infrared Spectroscopy

This is the first of two papers in which a study is made of a sample of 12 southern radio-luminous Seyfert galaxies. Our aim is to investigate possible correlations between radio morphology and nuclear/circumnuclear emission-line properties. In this paper we present radio images at 13, 6, and 3 cm taken with the Australia Telescope Compact Array (ATCA), global far-infrared (FIR) properties for the whole sample, and optical and near-infrared (NIR) spectroscopy of an interesting subset. We find a mixture of radio morphologies, including linear, diffuse and compact sources. When the FIR colors of the galaxies are considered there is an indication that the compact radio sources have warmer FIR colors than the diffuse sources, whereas the linear sources span a wide range of FIR colors. There is a wide variation in radio spectral-indices, suggesting that free-free absorption is significant in some systems, particularly IRAS 11249-2859, NGC 4507, and NGC 7213. Detailed emission-line studies are presented of 4 galaxies IC 3639, NGC 5135, NGC 3393 & IRAS 11249-2859. In IC 3639 we present evidence of vigorous, compact star formation enclosed by very extended [OI]6300 emission, suggestive of the boundary between a diffuse outflow and the surrounding ISM. In another galaxy, IC 5063, we see evidence for the possible interaction of a highly collimated outflow and the surrounding rotating inner disk. Of the 5 galaxies which show compact radio emission, 4 have radio/FIR flux ratios consistent with an energetically dominant AGN, whereas IC 4995 exhibits evidence for a very compact starburst.Comment: 42 pages, including 7 tables, latex, 19 jpeg figures, Accepted to ApJ. Replacement updates coordintes of galaxies in Table

A New Einstein Cross: A Highly Magnified, Intrinsically Faint Lyman-Alpha Emitter at z=2.7

We report the discovery of a new Einstein cross at redshift z_S = 2.701 based on Lyman-alpha emission in a cruciform configuration around an SDSS luminous red galaxy (z_L = 0.331). The system was targeted as a possible lens based on an anomalous emission line in the SDSS spectrum. Imaging and spectroscopy from the W. M. Keck Observatory confirm the lensing nature of this system. This is one of the widest-separation galaxy-scale lenses known, with an Einstein radius of ~1.84 arcsec. We present simple gravitational lens models for the system and compute the intrinsic properties of the lensed galaxy. The total mass of the lensing galaxy within the 8.8 +/- 0.1 kpc enclosed by the lensed images is (5.2 +/- 0.1) x 10^11 M_sun. The lensed galaxy is a low mass galaxy (0.2 L*) with a high equivalent-width Lyman-alpha line (EW_Lya_rest = 46 +/- 5 Angstroms). Follow-up studies of this lens system can probe the mass structure of the lensing galaxy, and can provide a unique view of an intrinsically faint, high-redshift, star-forming galaxy at high signal-to-noise ratio.Comment: ApJ Letters, in pres

The Sloan Lens ACS Survey. X. Stellar, Dynamical, and Total Mass Correlations of Massive Early-type Galaxies

We use stellar masses, photometry, lensing, and velocity dispersions to investigate empirical correlations for the final sample of 73 early-type lens galaxies (ETGs) from the SLACS survey. The traditional correlations (Fundamental Plane [FP] and its projections) are consistent with those found for non-lens galaxies, supporting the thesis that SLACS lens galaxies are representative of massive ETGs. The addition of strong lensing estimates of the total mass allows us to gain further insights into their internal structure: i) the mean slope of the total mass density profile is = 2.078+/-0.027 with an intrinsic scatter of 0.16+/-0.02; ii) gamma' correlates with effective radius and central mass density, in the sense that denser galaxies have steeper profiles; iii) the dark matter fraction within reff/2 is a monotonically increasing function of galaxy mass and size; iv) the dimensional mass M_dim is proportional to the total mass, and both increase more rapidly than stellar mass M*; v) the Mass Plane (MP), obtained by replacing surface brightness with surface mass density in the FP, is found to be tighter and closer to the virial relation than the FP and the M*P, indicating that the scatter of those relations is dominated by stellar population effects; vi) we construct the Fundamental Hyper-Plane by adding stellar masses to the MP and find the M* coefficient to be consistent with zero and no residual intrinsic scatter. Our results demonstrate that the dynamical structure of ETGs is not scale invariant and that it is fully specified by the total mass, r_eff, and sigma. Although the basic trends can be explained qualitatively in terms of varying star formation efficiency as a function of halo mass and as the result of dry and wet mergers, reproducing quantitatively the observed correlations and their tightness may be a significant challenge for galaxy formation models.Comment: 16 pages, 9 figures; submitted to ApJ after responding to the referee comment