Ages and metallicities of faint red galaxies in the Shapley Supercluster

We present results on the stellar populations of 232 quiescent galaxies in the Shapley Supercluster, based on spectroscopy from the AAOmega spectrograph at the AAT. The key characteristic of this survey is its coverage of many low-luminosity objects (sigma ~ 50 km/s), with high signal-to-noise (~45 per Angstrom). Balmer-line age estimates are recovered with ~25% precision even for the faintest sample members. We summarize the observations and absorption line data, and present correlations of derived ages and metallicities with mass and luminosity. We highlight the strong correlation between age and alpha-element abundance ratio, and the anti-correlation of age and metallicity at fixed mass, which is shown to extend into the low-luminosity regime.Comment: Four pages, three figures; To appear in Proceedings of IAU Symp. 245 "Formation and Evolution of Galaxy Bulges", (Oxford, July 16-20 2007), Eds. Martin Bureau, Lia Athanassoula, and Beatriz Barbu

ELEVATED Α-FETOPROTEIN IN ASSOCIATION WITH LOSS OF SERUM HBeAg

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73663/1/j.1572-0241.1993.tb07621.x.pd

Severe Cholestasis Associated with Methyltestosterone: A Case Report

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75504/1/j.1572-0241.1987.tb01706.x.pd

Hepatitis B infection and liver transplantation: The art of the possible

No Abstract.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38405/1/1840190134_ftp.pd

Are Recent Peculiar Velocity Surveys Consistent?

We compare the bulk flow of the SMAC sample to the predictions of popular cosmological models and to other recent large-scale peculiar velocity surveys. Both analyses account for aliasing of small-scale power due to the sparse and non-uniform sampling of the surveys. We conclude that the SMAC bulk flow is in marginal conflict with flat COBE-normalized Lambda-CDM models which fit the cluster abundance constraint. However, power spectra which are steeper shortward of the peak are consistent with all of the above constraints. When recent large-scale peculiar velocity surveys are compared, we conclude that all measured bulk flows (with the possible exception of that of Lauer & Postman) are consistent with each other given the errors, provided the latter allow for `cosmic covariance'. A rough estimate of the mean bulk flow of all surveys (except Lauer & Postman) is ~400 km/s towards l=270, b=0.Comment: 8 pages, 3 figures. To appear in Proceedings of the Cosmic Flows Workshop, Victoria, B. C., Canada, July 1999, eds. S. Courteau, M. Strauss, and J. Willic

Near-Infrared Imaging of Early-Type Galaxies IV. The Physical Origins of the Fundamental Plane Scaling Relations

The physical origins of the Fundamental Plane (FP) scaling relations are investigated for early-type galaxies observed at optical and near-infrared wavelengths. The slope for the FP is shown to increase systematically with wavelength from the U-band through the K-band. A distance-independent construction of the observables is described which provides an accurate measurement of the change in the FP slope between any pair of bandpasses. The variation of the FP slope with wavelength is strong evidence of systematic variations in stellar content along the elliptical galaxy sequence. The intercept of the diagnostic relationship between log(D_K/D_V) and log(sigma_0) shows no significant dependence on environment within the uncertainties of the Galactic extinction corrections, demonstrating the universality of the stellar populations contributions at the level of Delta(V-K)=0.03 mag to the zero-point of the global scaling relations. Several other constraints on the properties of early-type galaxies --- the slope of the Mg_2-sigma_0 relation, the effects of stellar populations gradients, and deviations of early-type galaxies from a dynamically homologous family --- are included to construct an empirical, self-consistent model which provides a complete picture of the underlying physical properties which are varying along the early-type galaxy sequence. This empirical approach demonstrates that there are significant systematic variations in both age and metallicity along the elliptical galaxy sequence, and that a small, but systematic, breaking of dynamical homology (or a similar, wavelength independent effect) is required. Predictions for the evolution of the slope of the FP with redshift are described. [abriged]Comment: to appear in The Astronomical Journal; 40 pages, including 10 Postscript figures and 3 tables; uses AAS LaTeX style file

Beyond Sérsic + exponential disc morphologies in the Coma Cluster

Galaxies are not limited to simple spheroid or bulge + disc morphologies. We explore the diversity of internal galaxy structures in the Coma Cluster across a wide range of luminosities (−17 > Mg > −22) and cluster-centric radii (0 10 kpc). 11 per cent of galaxies (N = 52) feature a break in their outer profiles, indicating ‘truncated’ or ‘antitruncated’ discs. Beyond the break radius, truncated galaxies are structurally consistent with exponential discs, disfavouring physical truncation as their formation mechanism. Bulge luminosity in antitruncated galaxies correlates strongly with galaxy luminosity, indicating a bulge-enhancing origin for these systems. Both types of broken disc are found overwhelmingly (>70 per cent) in ‘barred’ galaxies, despite a low measured bar fraction for Coma (20 ± 2 per cent). Thus, galaxy bars play an important role in formation of broken disc structures. No strong variation in galaxy structure is detected with projected cluster-centric radius

The Near-Infrared Fundamental Plane of Elliptical Galaxies

We present results from a near-infrared $K$-band imaging survey of 59 elliptical galaxies in five nearby clusters. We measure photometric parameters for each galaxy using surface photometry and draw velocity dispersions from the literature. Three observables define a near-infrared Fundamental Plane (FP) of elliptical galaxies with $R_e \propto \sigma^{1.44\pm0.04} \Sigma_e^{-0.79\pm0.04}$. The scatter in the near-infrared relation is small at $16.5$\% in distance, which is equivalent to, or less than, the scatter of the optical FP. We suggest that the small deviation of the near-infrared FP relation from the optical FP is due to the reduction of metallicity effects in the near-infrared bandpass. While the small scatter of the optical FP could be consistent with compensating effects of age and metallicity, the similarly small scatter of the near-infrared FP is nearly independent of metallicity and hence places a strong constraint on possible age spreads among elliptical galaxies at every point along the FP. We suggest that the departure of the near-infrared FP from the pure virial form $R_e \propto \sigma^2 \Sigma_e^{-1}$, and the corresponding observed relation $\left( M/L \right) \propto M^{0.16\pm 0.01}$, may be explained by slight systematic departures of the structure and dynamics of elliptical galaxies from a homology.Comment: to appear in The Astrophysical Journal (Letters); 12 pages, including 2 Postscript figures and 1 table; uuencoded, compressed format; the paper is also available in various formats from http://astro.caltech.edu/~map/map.bibliography.refereed.htm

CAGE

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28986/1/0000013.pd