相关论文: The core of the problem: Physical limits of the co…
New measurements of the stellar-mass deficits at the centers of luminous elliptical galaxies are presented. These were derived considering the following observational facts. Firstly, ``core'' galaxies, which are thought to have had their…
New surface brightness profiles from 26 early-type galaxies with partially depleted cores have been extracted from the full radial extent of HST images, giving us a total sample of 31 such core-Sersic galaxies. We have carefully quantified…
We have modelled the inner surface brightness profiles of 39 alleged `core' galaxies with the core-Sersic model, and provide new physical parameters for the largest ever sample of `core' galaxies fit with this model. When present,…
Popular models for describing the luminosity-density profiles of dynamically hot stellar systems (e.g., Jaffe, Hernquist, Dehnen) were constructed with the desire to match the deprojected form of an R^{1/4} light-profile. Real galaxies,…
We fit the surface-brightness profiles of 21 elliptical galaxies using both the Sersic function and a new empirical model which combines an inner power law with an outer Sersic function. The profiles are combinations of deconvolved HST…
I describe the advantage of using singular value decomposition as a diagnostic tool for exploring the potential and limitations of seismic data. Using stellar models coupled with the expected errors in seismic and complementary data we can…
This paper addresses some questions which have arisen from the use of the S\'ersic r^{1/n} law in modelling the luminosity profiles of early type galaxies. The first issue deals with the trend between the half-light radius and the…
We present a comprehensive description of the Sch\"onberg--Chandrasekhar (S--C) transition, which is an acceleration of the stellar evolution from the nuclear to the thermal time scales occurring when the fractional mass of the helium core…
We present observations of 15 massive cores in three different CS transitions from the FCRAO 14m and the KOSMA 3m telescope. We derive physical parameters of these cores using different approaches to the line radiative transfer problem. The…
The S\'ersic or $R^{1/m}$ model has become the de facto standard model to describe the surface brightness profiles of early-type galaxies and the bulges of spiral galaxies. The photometric, intrinsic, and dynamical properties of this model…
The inner and outer shapes and orientations of core-Sersic galaxies may hold important clues to their formation and evolution. We have therefore measured the central and outer ellipticities and position angles for a sample of 24 core-Sersic…
The Nuker law was designed to match the inner few (~3-10) arcseconds of predominantly nearby (< 30 Mpc) early-type galaxy light-profiles; it was never intended to describe an entire profile. The Sersic model, on the other hand, was…
The standard cosmological model, now strongly constrained by direct observation at early epochs, is very successful in describing the structure of the evolved universe on large and intermediate scales. Unfortunately, serious contradictions…
Massive stars are linked with diverse astronomical processes and objects including star formation, supernovae and their remnants, cosmic rays, interstellar media, and galaxy evolution. Understanding their properties is of primary importance…
Modeling galaxy formation in a cosmological context presents one of the greatest challenges in astrophysics today, due to the vast range of scales and numerous physical processes involved. Here we review the current status of models that…
We present spherical, non-rotating, isotropic models of early-type galaxies with stellar and dark-matter components both described by deprojected Sersic density profiles, and prove that they represent physically admissible stable systems.…
This paper considers the phenomenon of deep core collapse in collisional stellar systems, with stars of equal mass. The collapse takes place on some multiple, $\xi ^{-1}$, of the central relaxation time, and produces a density profile in…
The Sch\"onberg-Chandrasekhar (SC) limit is a well-established result in the understanding of stellar evolution. It provides an estimate of the point at which an evolved isothermal core embedded in an extended envelope begins to contract.…
The unprecedented quality of the asteroseismic data of solar-type stars made available by space missions such as NASA's Kepler telescope are making it possible to explore stellar interior structures. This offers possibilities of…
Recent years have seen dramatic progress in the study of the core and nuclear properties of galaxies. The structure of the cores has been shown to vary methodically with global and nuclear properties, as cores respond to the mechanisms by…