Ethical Obligations of the Attorney under Rule 23--Abuses and Reforms

This Comment will examine the ethical problems which have arisen as a result of the maintenance of class actions under Federal Rule 23, and will discuss the effect of a breach of ethics by the attorney on the members of the class. The specific problems to be considered are those of claim solicitation, attorney\u27s fees, problems involved in the dismissal or compromise of class actions, and some of the ethical questions involved in adequate representation of the class

A Wide-Field View of Leo II -- A Structural Analysis Using the SDSS

Using SDSS I data, we have analysed the stellar distribution of the Leo II dwarf spheroidal galaxy (distance of 233 kpc) to search for evidence of tidal deformation. The existing SDSS photometric catalogue contains gaps in regions of high stellar crowding, hence we filled the area at the centre of Leo II using the DAOPHOT algorithm applied to the SDSS images. The combined DAOPHOT-SDSS dataset contains three-filter photometry over a 4x4 square degree region centred on Leo II. By defining a mask in three-filter colour-magnitude space, we removed the majority of foreground field stars. We have measured the following Leo II structural parameters: a core radius of r_c = 2.64 +/- 0.19 arcmin (178 +/- 13 pc), a tidal radius of r_t = 9.33 +/- 0.47 arcmin (632 +/- 32 pc) and a total V-band luminosity of L_V = (7.4 +/- 2.0) times 10^5 L_sun (M_V = -9.9 +/- 0.3). Our comprehensive analysis of the Leo II structure did not reveal any significant signs of tidal distortion. The internal structure of this object contains only mild isophotal twisting. A small overdensity was discovered appoximately 4.5 tidal radii from the Leo II centre, however we conclude it is unlikely to be material tidally stripped from Leo II based on its stellar population, and is most likely a foreground overdensity of stars. Our results indicate that the influence of the Galactic graviational field on the structure of Leo II has been relatively mild. We rederived the mass-to-light ratio of this system using existing kinematic data combined with our improved structural measurements, and favour the scenario in which Leo II is strongly dominated by dark matter with (M/L)_V ~ 100 in solar units.Comment: 41 pages, 15 figures, accepted for publication in the Astronomical Journa

Dynamical Masses in Luminous Infrared Galaxies

We have studied the dynamics and masses of a sample of ten nearby luminous and ultraluminous infrared galaxies (LIRGS and ULIRGs), using 2.3 micron CO absorption line spectroscopy and near-infrared H- and Ks-band imaging. By combining velocity dispersions derived from the spectroscopy, disk scale-lengths obtained from the imaging, and a set of likely model density profiles, we calculate dynamical masses for each LIRG. For the majority of the sample, it is difficult to reconcile our mass estimates with the large amounts of gas derived from millimeter observations and from a standard conversion between CO emission and H_2 mass. Our results imply that LIRGs do not have huge amounts of molecular gas (10^10-10^11 Msolar) at their centers, and support previous indications that the standard conversion of CO to H_2 probably overestimates the gas masses and cannot be used in these environments. This in turn suggests much more modest levels of extinction in the near-infrared for LIRGs than previously predicted (A_V~10-20 versus A_V~100-1000). The lower gas mass estimates indicated by our observations imply that the star formation efficiency in these systems is very high and is triggered by cloud-cloud collisions, shocks, and winds rather than by gravitational instabilities in circumnuclear gas disks.Comment: 14 pages, 2 figures, accepted to Ap

Deformation of landfill from measurements of shear wave velocity and damping - Discussion

The author presents a method for using in-situ seismic test results to estimate the short-term deformations of geomaterials. The effort to introduce rational algorithms for the evaluation of settlements of shallow foundations on the basis of measured physical quantities is noteworthy, considering that current geotechnical design, especially on small-scale projects, is often based on empirical correlations between settlements and penetration test results that rarely reflect the actual site conditions. In this context the development of simple procedures based on the results of relatively inexpensive in-situ tests including seismic tests is of paramount importance. Nevertheless it is important to account properly for the physics of wave propagation when inferring material parameters from seismic test results. In this respect, the writers would like to make some observations related to the methods used to evaluate the shear wave velocity and material damping ratio of the solid waste from surface wave measurements. This discussion is focused on and restricted to the aspects of the paper related to the use of surface wave methods to estimate the waste properties

The Evolution of Rest-Frame K-band Properties of Early-Type Galaxies from z=1 to the Present

We measure the evolution of the rest-frame K-band Fundamental Plane from z=1 to the present by using IRAC imaging of a sample of early-type galaxies in the Chandra Deep Field-South at z~1 with accurately measured dynamical masses. We find that $M/L_K$ evolves as $\Delta\ln{(M/L_K)}=(-1.18\pm0.10)z$, which is slower than in the B-band ($\Delta\ln{(M/L_B)}=(-1.46\pm0.09)z$). In the B-band the evolution has been demonstrated to be strongly mass dependent. In the K-band we find a weaker trend: galaxies more massive than $M=2\times10^{11}M_{\odot}$ evolve as $\Delta\ln{(M/L_K)}=(-1.01\pm0.16)z$; less massive galaxies evolve as $\Delta\ln{(M/L_K)}=(-1.27\pm0.11)z$. As expected from stellar population models the evolution in $M/L_K$ is slower than the evolution in $M/L_B$. However, when we make a quantitative comparison, we find that the single burst Bruzual-Charlot models do not fit the results well, unless large dust opacities are allowed at z=1. Models with a flat IMF fit better, Maraston models with a different treatment of AGB stars fit best. These results show that the interpretation of rest-frame near-IR photometry is severely hampered by model uncertainties and therefore that the determination of galaxy masses from rest-frame near-IR photometry may be harder than was thought before.Comment: 5 pages, 3 figures, Accepted for publication in ApJ

Mass-to-Light Ratios of Field Early-Type Galaxies at z~1 from Ultra-Deep Spectroscopy: Evidence for Mass-dependent Evolution

We present an analysis of the Fundamental Plane for a sample of 27 field early-type galaxies in the redshift range 0.6<z<1.15. The galaxies in this sample have high S/N spectra obtained at the VLT and high resolution imaging from the ACS. We find that the mean evolution in M/L of our sample is $Delta ln (M/L_B) = -1.74+/-0.16z$, with a large galaxy-to-galaxy scatter. This value can be too low by 0.3 due to selection effects, resulting in $Delta ln (M/L_B) = -1.43+/-0.16z$. The strong correlation between M/L and rest-frame color indicates that the observed scatter is not due to measurement errors, but due to intrinsic differences between the stellar populations of the galaxies. This pace of evolution is much faster than the evolution of cluster galaxies. However, we find that the measured M/L evolution strongly depends on galaxy mass. For galaxies with masses $M>2 x 10^11 Msol$, we find no significant difference between the evolution of field and cluster galaxies: $Delta ln (M/L_B) = -1.20+/-0.18z for field galaxies and$Delta ln (M/L_B) = -1.12+/-0.06z$ for cluster galaxies. The relation between the measured M/L evolution and mass is partially due to selection effects. However, even when taking selection effects into account, we still find a relation between M/L evolution and mass, which is most likely caused by a lower mean age and a larger intrinsic scatter for low mass galaxies. Results from lensing early-type galaxies, which are mass-selected, show a very similar trend with mass. This, combined with our findings, provides evidence for down-sizing. Previous studies of the rate of evolution of field early-type galaxies found a large range of mutually exclusive values. We show that these differences are largely caused by the differences between fitting methods. (Abridged)Comment: figures 3 and 4 available at http://www.strw.leidenuniv.nl/~vdwel/private/FPpaper