相关论文: Stellar Orbits and the Interstellar Gas Temperatur…
We study the chemo-dynamical evolution of elliptical galaxies and their hot X-ray emitting gas using high-resolution cosmological simulations. Our Tree N-body/SPH code includes a self-consistent treatment of radiative cooling, star…
(shortened for babbage) We describe (1) a new test for dark matter and alternate theories of gravitation based on the relative geometries of the X-ray and optical surface brightness distributions and an assumed form for the potential of the…
The dense cores of X-ray emitting gaseous halos of large elliptical galaxies with temperatures below about 0.8 keV show two prominent Fe XVII emission features, which provide a sensitive diagnostic tool to measure the effects of resonant…
We present analysis of a Chandra observation of the elliptical galaxy NGC 4555. The galaxy lies in a very low density environment, either isolated from all galaxies of similar mass or on the outskirts of a group. Despite this, NGC 4555 has…
The temperature profile of hot gas in galaxies and galaxy clusters is largely determined by the depth of the total gravitational potential and thereby by the dark matter (DM) distribution. We use high-resolution hydrodynamical simulations…
For a sample of 9 well-studied giant ellipticals we compare the projected radial distribution of their red and blue globular cluster (GC) subpopulations with their host galaxy stellar and X-ray surface brightness profiles. We support…
We study the dynamical properties of spherical galaxies with surface luminosity profile described by the R^{1/m}-law, in which a variable degree of orbital anisotropy is allowed. The parameter m for the present models covers the range…
A simple spherically-symmetric, steady-state, cooling-flow description with gas loss (following Sarazin \& Ashe 1989), within galaxy models constrained by radially extended stellar dynamical data, is shown to provide generally reasonable…
In this paper we have made an attempt to derive the radial profiles of density and temperature of intracluster gas based on the two well-established facts at present: the X-ray observed surface brightness of clusters described by the…
We present an analysis of the hot interstellar medium (ISM) in the spiral galaxy NGC 4490, which is interacting with the irregular galaxy NGC 4485, using ~100ks of Chandra ACIS-S observations. The high angular resolution of Chandra enables…
Important clues to the chemical and dynamical history of elliptical galaxies are encoded in the abundances of heavy elements in the X-ray emitting plasma. We derive the hot ISM abundance pattern in inner and outer regions of NGC 4472 from…
We report on mid- and far-IR Spitzer observations of 7 nearby dusty elliptical galaxies by using the Multiband Imaging Photometer (MIPS) and Infrared Spectrograph (IRS). Our sample galaxies are known to contain an excessive amount of…
The effect of the nebula optical depth on the determination of the temperature (T*) of the central stars in planetary nebulae is discussed. Based on photoionization models for planetary nebulae with different optical depths, we show,…
We have analyzed ROSAT PSPC X-ray data of the optically elongated S0 galaxy NGC 1332 with the purposes of constraining the intrinsic shape of its underlying mass and presenting a detailed investigation of the uncertainties resulting from…
Using high-resolution non-radiative hydrodynamic simulations of galaxy clusters we obtain simple analytic formulae for DM and gas distribution in the spherical approximation. We derive fits for the DM density, velocity dispersion and…
The star formation rate in galaxies should be related to the fraction of gas that can attain densities large enough for gravitational collapse. In galaxies with a turbulent interstellar medium, this fraction is controlled by the effective…
We present direct observational constraints on the orbital distribution of the stars in the giant elliptical NGC 2320. Long-slit spectra along multiple position angles are used to derive the stellar line-of-sight velocity distribution…
The neutral hydrogen 21 cm line is an excellent tracer of the atomic interstellar medium in the cold and the warm phases. Combined 21 cm emission and absorption observations are very useful to study the properties of the gas over a wide…
We present a Chandra study of the hot ISM in the giant elliptical galaxy NGC4649. In common with other group-centred ellipticals, its temperature profile rises with radius in the outer parts of the galaxy, from ~0.7keV at 2kpc to ~0.9keV by…
We present density profiles, that are solutions of the spherical Jeans equation, derived under the following two assumptions: (i) the coarse grained phase-density follows a power-law of radius, rho/(sigma^3) proportional to r^{-alpha}, and…