Total Mass Density Research Articles

Ion composition in the plasma trough and plasma plume derived from a Combined Release and Radiation Effects Satellite magnetoseismic study

The mass and energy carried in the magnetosphere by heavy ions, O+ in particular, are known to increase as geomagnetic activity increases. However, the ion composition in the magnetosphere has not been fully specified since measurements of the flux of different ion species from the ionospheric thermal energy (below 1 eV) to the ring current energy (above 100 keV) are difficult with single‐particle instruments. We used mass density determined by a magnetoseismology technique and the electron density derived from measured plasma wave spectra to investigate the ion composition and total mass density for Combined Release and Radiation Effects Satellite (CRRES) orbit 962 (27−28 August 1991). This orbit occurred during a geomagnetic storm and included afternoon passes through the plasmasphere, the plasma trough, and a plasma plume, where these plasma regions were identified using the electron density ne. In the magnetoseismology analysis, we determined the fundamental frequency of the toroidal standing Alfvén waves fT1 from the electric and magnetic field data and then inferred the corresponding total mass density ρtotal at the satellite by solving an MHD wave equation with a realistic magnetic field model and a realistic assumption for the mass distribution along the field line. The value of fT1 changed little when the spacecraft moved between the plasma trough and the plasma plume, implying the dominance of heavy ions in the plasma trough. From the values of ne and ρtotal, we derived quantities associated with O+ by assuming that the plasma consisted of three ions, H+, He+, and O+. In the plasma trough, O+ ions are found to carry a number density of ∼10 cm−3, ∼50% of the number density, and ∼90% of the mass density. On the other hand, O+ is found to be much less dominant in the plasma plume. Our results are consistent with DE‐1 studies of the formation of an oxygen torus at the outer edge of the H+ plasmapause during geomagnetic active periods and with GEOS‐1 and GEOS‐2 studies that reported strong dependence of O+ density on geomagnetic activity and on solar extreme ultraviolet flux. In addition, our events indicate that the plasma plume boundary, defined in terms of the number density of electrons or light ions (H+ and He+), may not exhibit similar structure in the total mass density that can be readily detected using magnetoseismology techniques.

Measurement of small-strain shear modulus Gmax of dry and saturated sands by bender element, resonant column, and torsional shear tests

The bender element method is an experimental technique used to determine the small-strain shear modulus (Gmax) of a soil by measuring the velocity of shear wave propagation through a sample. Bender elements have been applied as versatile transducers to measure the Gmax of wet and dry soils in various laboratory apparatuses. However, certain aspects of the bender element method have yet to be clearly specified because of uncertainties in determining travel time. In this paper, the bender element (BE), resonant column (RC), and torsional shear (TS) tests were performed on the same specimens using the modified Stokoe-type RC and TS testing equipment. Two clean sands, Toyoura and silica sands, were tested at various densities and mean effective stresses under dry and saturated conditions. Based on the test results, methods of determining travel time in BE tests were evaluated by comparing the results of RC, TS, and BE tests. Also, methods to evaluate Gmax of saturated sands from the shear-wave velocity (Vs) obtained by RC and BE tests were investigated by comparing the three sets of test results. Biot’s theory on frequency dependence of shear-wave velocity was adopted to consider dispersion of a shear wave in saturated conditions. The results of this study suggest that the total mass density, which is commonly used to convert Gmax from the measured Vs in saturated soils, should not be used to convert Vs to Gmax when the frequency of excitation is 10% greater than the characteristic frequency (fc) of the soil.

Two-phase, partially miscible flow and transport modeling in porous media; application to gas migration in a nuclear waste repository

We derive a compositional compressible two-phase, liquid and gas, flow model for numerical simulations of hydrogen migration in deep geological repository for radioactive waste. This model includes capillary effects and the gas high diffusivity. Moreover, it is written in variables (total hydrogen mass density and liquid pressure) chosen in order to be consistent with gas appearance or disappearance. We discuss the well possedness of this model and give some computational evidences of its adequacy to simulate gas generation in a water-saturated repository.

Mass distribution and orbital anisotropy of early-type galaxies: constraints from the mass plane

Massive early-type galaxies are observed to lie on the mass plane (MP), a two-dimensional manifold in the space of effective radius Re, projected mass M p (measured via strong gravitational lensing) and projected stellar velocity dispersion σ e2 withinRe/2. The MP is less ‘tilted’ than the traditional Fundamental Plane, and the two have comparable associated scatter. This means that the dimensionless structure parameter ce2 = 2GM p /(Reσ 2 ) is a nearly universal constant in the range σ e2 = 175–400 km s −1 . This finding can be used to constrain the mass distribution and internal dynamics of early-type galaxies: in particular, we explore the dependence of ce2 on light profile, dark matter distribution, and orbital anisotropy for several families of spherical galaxy models. We find that a relatively wide class of models has values of ce2 in the observed range, because ce2 is not very strongly sensitive to the mass distribution and orbital anisotropy. The degree of fine-tuning required to match the small intrinsic scatter of ce2 depends on the considered family of models: if the total mass distribution is isothermal (∝ r −2 ), a broad range of stellar luminosity profile and anisotropy is consistent with the observations, while Navarro, Frenk & White dark matter haloes require more fine-tuning of the stellar mass fraction, luminosity profile and anisotropy. If future data can cover a broader range of masses, the MP could be seen to be tilted by the known non-homology of the luminosity profiles of early-type galaxies, and the value of any such tilt would provide a discriminant between models for the total mass–density profile of the galaxies.

An empirical relation to correct storm-time thermospheric mass density modeled by NRLMSISE-00 with CHAMP satellite air drag data

With the help of STAR (Spatial Triaxial Accelerometer for Research) accelerometer measurements on board CHAMP (Challenging Minisatellite Payload), the global distributions of total mass density changes at about 400 km height during major magnetic storms are studied, aiming to improve the capability of current thermospheric model for predicting the storm-time mass density distribution. The density calculated by the NRLMSISE-00 model without using the geomagnetic active index as input is taken as a reference on top of which the storm-time changes are added. In total 19 storm events during 2001–2004 are used to perform a comprehensive statistical analysis. A relative calibration of drag coefficient along with accelerometer calibration parameters is made by fitting the CHAMP observed initial mass densities in with the NRLMSISE-00 model on quiet days before each storm. The dependences of the storm-time changes in mass density on both the total global Joule heating power, ∑ Q j and the high-resolution ring current index, Sym-H, are investigated. The lag times of mass density changes with respect to the Joule heating and Sym-H variation are obtained as a function of latitude and sunlight. By using a multiple linear regression analysis with proper time shift, an empirical relation connecting storm-time changes in mass density for 400 km height with the two parameters, ∑ Q j and Sym-H, has been worked out for different latitude and sunlight conditions (day-side or night-side). Adding a correction calculated from the empirical relation to the NRLMSISE-00 model reference leads to a better prediction of storm-time thermospheric mass density distribution.

The Sloan Lens ACS Survey. VI. Discovery and Analysis of a Double Einstein Ring1

We report the discovery of two concentric partial Einstein rings around the gravitational lens SDSSJ0946+1006, as part of the Sloan Lens ACS Survey. The main lens is at redshift zl = 0.222, while the inner ring (1) is at redshift zs1 = 0.609 and Einstein radius REin1 = 1.43 ± 0.01 00 . The wider image separation (REin2 = 2.07±0.02 00 ) of the outer ring (2) implies that it is at higher redshift than Ring 1. Although no spectroscopic feature was detected in » 9 hours of spectroscopy at the Keck I Telescope, the detection of Ring 2 in the F814W ACS filter implies an upper limit on the redshift of zs2 . 6.9. The lens configuration can be well described by a power law total mass density profile for the main lens ‰tot / r i∞ 0 with logarithmic slope ∞ 0 = 2.00±0.03 (i.e. close to isothermal), velocity dispersion aeSIE = 287 ± 5kms i1 (in good agreement with the stellar velocity dispersion aev,⁄ = 284 ± 24kms i1 ) with little dependence upon cosmological parameters or the redshift of Ring 2. Using strong lensing constraints only we show that the enclosed mass to light ratio increases as a function of radius, inconsistent with mass following light. Adopting a prior on the stellar mass to light ratio from previous SLACS work we infer that 73 ± 9% of the mass is in form of dark matter within the cylinder of radius equal to the eective radius of the lens. We consider whether the double source plane configuration can be used to constrain cosmological parameters exploiting the ratios of angular distance ratios entering the set of lens equations. We find that constraints for SDSSJ0946+1006 are uninteresting due to the sub-optimal lens and source redshifts for this application. We then consider the perturbing eect of the mass associated with Ring 1 (modeled as a singular isothermal sphere) building a double lens plane compound lens model. This introduces minor changes to the mass of the main lens, allows to estimate the redshift of the Ring 2 (zs2 = 3.1 +2.0 i1.0 ), and the mass of the source responsible for Ring 1 (aeSIE,s1 = 94 +2747 kms i1 ). We conclude by examining the prospects of doing cosmography with a sample of 50 double source plane gravitational lenses, expected from future space based surveys such as DUNE or JDEM. Taking full account of the uncertainty in the mass density profile of the main lens, and of the eect of the perturber, and assuming known redshifts for both sources, we find that such a sample could be used to measure ›m and w with 10% accuracy, assuming a flat cosmological model. Subject headings: Gravitational lensing ‐ galaxies : Ellipticals and lenticulars, cD ‐ galaxies: structure ‐ galaxies: halos ‐ cosmology: dark matter ‐ cosmology: cosmological parameters

Wave-Based Techniques for Evaluating Elastic Modulus and Poisson’s Ratio of Laboratory Compacted Lateritic Soils

A rapid, low-cost evaluation methodology using the wave-based techniques is proposed in this study in order to determine the design parameters e.g., elastic modulus and Poisson’s ratio of the laboratory compacted lateritic soils. Knowing the elastic wave velocities as measured with the wave propagation technique (i.e., a small-strain non-destructive test) and total mass density of the specimens, the elastic moduli and Poisson’s ratio of the soil specimens can be determined. In addition, the unconfined compression test (i.e., a large-strain destructive test) is also performed on the same specimens under the same unconfined testing condition in order to compare the moduli corresponding to different strain levels. The experimental results showed the potentials and limitations of using impulse signal for the determination of the elastic moduli and Poisson’s ratio for laboratory compacted soil specimens from elastic wave propagation techniques.

Direct Cosmological Simulations of the Growth of Black Holes and Galaxies

We investigate the coupled formation and evolution of galaxies and their embedded supermassive black holes using state-of-the-art hydrodynamic simulations of cosmological structure formation. For the first time, we self-consistently follow the dark matter dynamics, radiative gas cooling, and star formation, as well as BH growth and associated feedback processes, starting directly from initial conditions appropriate for the ΛCDM cosmology. Our modeling of the black hole physics is based on an approach that we have developed in simulations of isolated galaxy mergers. Here we examine (1) the predicted global history of BH mass assembly, (2) the evolution of the local black hole-host mass correlations, and (3) the conditions that allow rapid growth of the first quasars, and the properties of their hosts and descendants today. We find a total BH mass density in good agreement with observational estimates. The BH accretion rate density peaks at lower redshift and evolves more strongly at high redshift than the star formation rate density, but the ratio of black hole to stellar mass density shows only a moderate evolution at low redshifts. We find strong correlations between BH masses and properties of the stellar systems, agreeing well with the measured local MBH-σ and MBH-M* relationships, but also suggesting (dependent on the mass range) a weak evolution with redshift in the normalization and the slope. Our simulations also produce massive black holes at high redshift, due to extended periods of exponential growth in regions that collapse early and exhibit strong gas inflows. These first supermassive BH systems, however, are not necessarily the most massive ones today, since they are often overtaken in growth by quasars that form later.

Neutrino mass, dark energy, and the linear growth factor

We study the degeneracies between neutrino mass and dark energy as they manifest themselves in cosmological observations. In contradiction to a popular formula in the literature, the suppression of the matter power spectrum caused by massive neutrinos is not just a function of the ratio of neutrino to total mass densities ${f}_{\ensuremath{\nu}}={\ensuremath{\Omega}}_{\ensuremath{\nu}}/{\ensuremath{\Omega}}_{m}$, but also each of the densities independently. We also present a fitting formula for the logarithmic growth factor of perturbations in a flat universe, $f(z,k;{f}_{\ensuremath{\nu}},w,{\ensuremath{\Omega}}_{\mathrm{DE}})\ensuremath{\approx}[1\ensuremath{-}A(k){\ensuremath{\Omega}}_{\mathrm{DE}}{f}_{\ensuremath{\nu}}+B(k){f}_{\ensuremath{\nu}}^{2}\ensuremath{-}C(k){f}_{\ensuremath{\nu}}^{3}]{\ensuremath{\Omega}}_{m}^{\ensuremath{\alpha}}(z)$, where $\ensuremath{\alpha}$ depends on the dark energy equation of state parameter $w$. We then discuss cosmological probes where the $f$ factor directly appears: peculiar velocities, redshift distortion, and the integrated Sachs-Wolfe effect. We also modify the approximation of Eisenstein and Hu [Astrophys. J. 511, 5 (1999)] for the power spectrum of fluctuations in the presence of massive neutrinos and provide a revised code [http://www.star.ucl.ac.uk/~lahav/nu_matter_power.f].

Thermospheric global average density trends, 1967–2007, derived from orbits of 5000 near‐Earth objects

We use orbit data on ∼5000 near‐Earth space objects to investigate long‐term trends in thermospheric total mass density, which has been predicted to decrease with time due to increasing CO2 concentrations. We refine and extend to 2007 previous density trend estimates, and investigate solar cycle‐dependent bias in empirical density models previously used to filter out solar irradiance effects. We find that the bias is caused in part by the solar cycle dependence of the long‐term trends, and we develop a new representation of solar cycle, seasonal, and geomagnetic activity effects. At 400 km, we estimate an overall trend of –2.68 ± 0.49 % per decade and trends of ∼–5 and –2 % per decade at solar minimum and maximum, respectively, in fair quantitative agreement with theoretical predictions. The global average density trends also depend on the phase of the year, with the strongest trends around October and weak trends in January.

Detection of non-ordered central gas motions in a sample of four low surface brightness galaxies

Aims. We present integral-field spectroscopy of the ionized gas in the central regions of four galaxies with a low surface brightness disk taken with the Visible Multi Object Spectrograph at the Very Large Telescope and aimed at testing the accuracy in the determination of the central logarithmic slope α of the mass density radial profile ρ(r) ∝ r α in this class of objects. Methods. For all the sample galaxies we subtracted the best-fit model of gas in circular motions from the observed velocity field and derived the residuals. Only ESO-LV5340200 is characterized by a regular velocity field. We extracted the velocity curves of this galaxy along several position angles, in order to estimate the uncertainty in deriving the central gradient of the total mass density from long-slit spectroscopy. Results. We report the detection of strong non-ordered motions of the ionized gas in three out of four sample galaxies. The deviations have velocity amplitudes and spatial scales that keep it from being possible to disentangle the cuspy and core density radial profiles.

Reliable Estimates of Planetary and Solar Magnetic Fields – A Case for Abundance of Hydrogen in the Earth’s Core

Inhalt: W. SCHRÖDER: Über die wissenschaftliche Beziehungen von Hans Ertel und Heinrich Ficker A. MACH – Z. MOSZNER: On Some Functional Equations Involving Involutions L. CĂDARIU – V. RADU: Remarks on the Stability of a Functional Equation of Quadratic Type I. CHAJDA – H. LÄNGER: Generalizations of Implication Algebras F. PASCHKE: Reliable Estimates of Planetary and Solar Magnetic Fields – A Case for Abundance of Hydrogen in the Earth's Core F. SCHWEIGER: The Invariant Measure for the Two-Dimensional Parry-Daniels Map H. HAUPT – G. HAHN: Kleine Planeten, deren Namen einen Österreichbezug aufweisen (II) P. STEINHAUSER: Zur Kombinationswirkung von Schall und Erschütterungen

A census of metals and baryons in stars in the local Universe

We combine stellar metallicity and stellar mass estimates for a large sample of galaxies drawn from the SDSS DR2 spanning wide ranges in physical properties, in order to derive an inventory of the total mass of metals and baryons locked up in stars today. Physical parameter estimates are derived from galaxy spectra with high S/N (>20). Coadded spectra of galaxies with similar velocity dispersions, absolute r-band magnitudes and 4000\AA-break values are used for those regions of parameter space where individual spectra have lower S/N. We estimate the total density of metals and of baryons in stars and, from these two quantities, we obtain a mass- and volume-averaged stellar metallicity of <Z_star>=1.04+-0.14 Z_sun, i.e. consistent with solar. We also study how metals are distributed in galaxies according to their mass, morphology and age, and we then compare these distributions with the corresponding distributions of stellar mass. We find that the bulk of metals locked up in stars in the local Universe reside in massive, bulge-dominated galaxies, with red colours and high 4000\AA-break values corresponding to old stellar populations. Bulge-dominated and disc-dominated galaxies contribute similar amounts to the total stellar mass density, but have different fractional contributions to the mass density of metals in stars, in agreement with the mass-metallicity relation. Bulge-dominated galaxies contain roughly 40% of the total amount of metals in stars, while disc-dominated galaxies less than 25%. Finally, at a given galaxy stellar mass, we define two characteristic ages as the median of the distributions of mass and metals as a function of age. These characteristic ages decrease progressively from high-mass to low-mass galaxies, consistent with the high formation epochs of stars in massive galaxies.

On invisible plasma content in radio-loud AGNs: the case of TeV blazar Markarian 421

Invisible plasma content in blazar jets such as protons and/or thermal electron-positron (e ± ) pairs is explored through combined arguments of dynamical and radiative processes. By comparing physical quantities required by the internal shock model with those obtained through the observed broad-band spectra for Mrk 421, we obtain that the ratio of the Lorentz factors of a pair of cold shells resides in about 2 ∼ 20, which implies that the shocks are at most mildly relativistic. Using the obtained Lorentz factors, the total mass density p in the shocked shells is investigated. The upper limit of p is obtained from the condition that thermal bremsstrahlung emission should not exceed the observed γ-ray luminosity, whilst the lower limit is constrained from the condition that the energy density of non-thermal electrons is smaller than that of the total plasma. Then, we find p is 10 2 -10 3 times heavier than that of non-thermal electrons for pure e ± pairs, while 10 2 -10 6 times heavier for pure electron-proton (e/p) content, implying the existence of a large amount of invisible plasma. The origin of the continuous blazar sequence is briefly discussed and we speculate that the total mass density and/or the blending ratio of e ± pairs and e/p plasma could be new key quantities for the origin of the sequence.

The contribution of very massive high-redshift SWIRE galaxies to the stellar mass function

(Abridged) We selected high-z massive galaxies at 5.8 microns, in the SWIRE ELAIS-S1 field (1 sq. deg.). Galaxies with the 1.6 microns stellar peak redshifted into the IRAC bands (z~1-3, called ``IR-peakers'') were identified. Stellar masses were derived by means of spectro-photometric fitting and used to compute the stellar mass function (MF) at z=1-2 and 2-3. A parametric fit to the MF was performed, based on a Bayesian formalism, and the stellar mass density of massive galaxies above z=2 determined. We present the first systematic study of the very-massive tail of the galaxy stellar mass function at high redshift. A total of 326 sources were selected. The majority of these galaxies have stellar masses in excess of 1e11 Msun and lie at z>1.5. The availability of mid-IR data turned out to be a valuable tool to constrain the contribution of young stars to galaxy SEDs, and thus their M(stars)/L ratio. The influence of near-IR data and of the chosen stellar library on the SED fitting are also discussed. A significant evolution is found not only for galaxies with M~1e11 Msun, but also in the highest mass bins considered. The comoving number density of these galaxies was lower by more than a factor of 10 at z=2-3, with respect to the local estimate. SWIRE 5.8 micron peakers more massive than 1.6x1e11 Msun provide 30-50% of the total stellar mass density in galaxies at z=2-3.

The Mass Function of Active Black Holes in the Local Universe

We present the first measurement of the BH mass function for broad-line active galaxies in the local universe. Using the ~8500 broad-line active galaxies from SDSS DR4, we construct a broad-line luminosity function that agrees very well with the local soft X-ray luminosity function. Using standard virial relations, we then convert observed broad-line luminosities and widths into BH masses. A mass function constructed in this way has the unique capability to probe the mass region <106 M☉, which, while insignificant in terms of total BH mass density, nevertheless may place important constraints on the mass distribution of seed BHs in the early universe. The characteristic local active BH has a mass of ~107 M☉ radiating at 10% of the Eddington rate. The active fraction is a strong function of BH mass; at both higher and lower masses the active mass function falls more steeply than one would infer from the distribution of bulge luminosity. The deficit of local massive radiating BHs is a well-known phenomenon, while we present the first robust measurement of a decline in the space density of active BHs at low mass.

The Sloan Lens ACS Survey. IV. The Mass Density Profile of Early‐Type Galaxies out to 100 Effective Radii

We present a weak gravitational lensing analysis of 22 early-type strong lens galaxies, based on deep HST images obtained as part of the Sloan Lens ACS Survey. Using the most advanced techniques to control systematic uncertainties related to the variable PSF and charge transfer efficiency of the ACS, we detect weak lensing signal out to 300 kpc/h. We analyze blank control fields from the COSMOS survey in the same manner, inferring that the residual systematic uncertainty in the tangential shear is <0.3%. A joint strong and weak lensing analysis shows that the average total mass density profile is consistent with isothermal over two decades in radius (3-300 kpc/h, approximately 1-100 Reff). This finding extends by over an order of magnitude in radius previous results, based on strong lensing and/or stellar dynamics, that luminous and dark component ``conspire'' to form an isothermal mass distribution. In order to disentangle the contributions of luminous and dark matter, we fit a two-component mass model (R^1/4 + NFW) to the weak and strong lensing constraints. It provides a good fit to the data with only two free parameters; i) the average stellar mass-to-light ratio M_*/L_V=4.48 +- 0.46 hMo/Lo, in agreement with that expected for an old stellar population; ii) the average virial mass-to-light ratio M_vir/L_V = 246+101-87 hMo/Lo. [abridged]

Star Formation in a Cosmological Simulation of Reionization

We study the luminosity functions of high-redshift galaxies in detailed hydrodynamic simulations of cosmic reionization, which are designed to reproduce the evolution of the Lyman-alpha forest between z=5 and z=6. We find that the luminosity functions and total stellar mass densities are in agreement with observations when plausible assumptions about reddenning at z=6 are made. Our simulations support the conclusion that stars alone reionized the universe.

Changes of Thermospheric Mass Density and Their Relations with Joule Heating and Ring Current Index During Nov. 2003 Superstorm—CHAMP Observations

AbstractUsing the accelerometer measurements on board CHAMP during the severe geomagnetic storm of November 20‐21, 2003, a study is made on the global distribution of the storm‐time changes in thermospheric total mass density at about 400 km height. The mutual relations of the storm‐time changes with the global integrated Joule heating power produced by large convective electric field, as well as with the ring current index of SYM‐H have also been investigated. It is found that the total mass density increased greatly during the November 2003 super‐storm, showing dramatic deviation from that predicted by NRLMSISE‐00 model. The density increases exhibit strong day‐night asymmetry, with larger augment and more complicated pattern versus latitude on the dayside. It shows a double peak‐like distribution at low‐mid latitudes with two prominent peaks at the equator and 45°S latitude respectively, while one of the strongest local maximum of the density enhancement occurs in the polar region. On the other hand, the density changes on the night‐side are somewhat hemispheric symmetrical in comparison with that on the dayside and the augment is stronger at lower latitudes. Elaborate cross‐correlation analyses reveal that the changes of the total mass density lag behind the Joule heating by 3~7 hours and behind the ring current index (SYM‐H) by 0~3 hours. The high correlation coefficients indicate that the mass density changes during the magnetic storm largely depend on both the polar Joule heating and the low‐latitude processes associated with the equatorial ring current.

Bright and dark matter in elliptical galaxies: mass and velocity distributions from self-consistent hydrodynamical simulations

[Abridged] We have analysed the mass and velocity distributions of two samples of relaxed elliptical-like-objects (ELOs) identified, at z=0, in a set of self-consistent hydrodynamical simulations operating in the context of a concordance cosmological model. Our analysis shows that they are embedded in extended, massive dark matter haloes, and they also have an extended corona of hot diffuse gas. Dark matter haloes have experienced adiabatic contraction along their assembly process. The relative ELO dark- to bright-mass content and space distributions show broken homology, and they are consistent with observational results on the dark matter fraction at the central regions, as well as on the gradients of the mass-to-light ratio profiles for boxy ellipticals, as a function of their stellar masses. These results indicate that massive ellipticals miss stars at their central regions, as compared with less massive ones. Our simulations indicate that these missing baryons could be found beyond the virial radii as a hot, diffuse plasma. The projected stellar mass profiles of our ELOs can be well fit by the S\'ersic (1968) formula. Parameters of these fits reproduce observational correlations of the shape parameter with size, luminosity and velocity dispersion. The total mass density profiles show a power-law behaviour over a large r/r_{vir} interval, consistent with data on massive lens ellipticals at shorter radii. The velocity dispersion profiles show kinematical segregation, with no systematic mass dependence and a positive anisotropy, roughly independent of the radial distance outside the central regions. The consistency with observations strongly suggests that they could also describe important intrinsic characteristics of real ellipticals, as well as some of their properties recently inferred from observational data.