Resonance Line Scattering Modifies X‐Ray Surface Brightness of Elliptical Galaxies

1998 ◽  
Vol 497 (2) ◽  
pp. 587-593 ◽  
Author(s):  
Toshikazu Shigeyama
Keyword(s):  
Resonance Line ◽  
Surface Brightness ◽  
Elliptical Galaxies ◽  
X Ray

scholarly journals The diverse X-ray properties of four truly isolated elliptical galaxies: NGC 2954, NGC 6172, NGC 7052, and NGC 7785

2009 ◽  
Vol 497 (2) ◽  
pp. 359-370 ◽  
Author(s):  
E. Memola ◽  
G. Trinchieri ◽  
A. Wolter ◽  
P. Focardi ◽  
B. Kelm
Keyword(s):  
Elliptical Galaxies ◽  
X Ray

scholarly journals An improved deprojection and PSF-deconvolution technique for galaxy-cluster X-ray surface-brightness profiles

2006 ◽  
Vol 459 (3) ◽  
pp. 1007-1019 ◽  
Author(s):  
J. H. Croston ◽  
M. Arnaud ◽  
E. Pointecouteau ◽  
G. W. Pratt
Keyword(s):  
Surface Brightness ◽  
Galaxy Cluster ◽  
X Ray ◽  
Deconvolution Technique

scholarly journals Figuring Out Gas & Galaxies In Enzo (FOGGIE). V. The Virial Temperature Does Not Describe Gas in a Virialized Galaxy Halo

2021 ◽  
Vol 922 (2) ◽  
pp. 121
Author(s):  
Cassandra Lochhaas ◽  
Jason Tumlinson ◽  
Brian W. O’Shea ◽  
Molly S. Peeples ◽  
Britton D. Smith ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Surface Brightness ◽  
Radiative Cooling ◽  
Low Density ◽  
Energy Partition ◽  
X Ray ◽  
Stellar Feedback ◽  
Galaxy Halo ◽  
Definition Of ◽  
Halo Gas

Abstract The classical definition of the virial temperature of a galaxy halo excludes a fundamental contribution to the energy partition of the halo: the kinetic energy of nonthermal gas motions. Using simulations of low-redshift, ∼L* galaxies from the Figuring Out Gas & Galaxies In Enzo (FOGGIE) project that are optimized to resolve low-density gas, we show that the kinetic energy of nonthermal motions is roughly equal to the energy of thermal motions. The simulated FOGGIE halos have ∼2× lower bulk temperatures than expected from a classical virial equilibrium, owing to significant nonthermal kinetic energy that is formally excluded from the definition of T vir. We explicitly derive a modified virial temperature including nonthermal gas motions that provides a more accurate description of gas temperatures for simulated halos in virial equilibrium. Strong bursts of stellar feedback drive the simulated FOGGIE halos out of virial equilibrium, but the halo gas cannot be accurately described by the standard virial temperature even when in virial equilibrium. Compared to the standard virial temperature, the cooler modified virial temperature implies other effects on halo gas: (i) the thermal gas pressure is lower, (ii) radiative cooling is more efficient, (iii) O vi absorbing gas that traces the virial temperature may be prevalent in halos of a higher mass than expected, (iv) gas mass estimates from X-ray surface brightness profiles may be incorrect, and (v) turbulent motions make an important contribution to the energy balance of a galaxy halo.

scholarly journals Surface brightness fluctuation distances for nearby dwarf elliptical galaxies

2001 ◽  
Vol 380 (1) ◽  
pp. 90-101 ◽  
Author(s):  
H. Jerjen ◽  
R. Rekola ◽  
L. Takalo ◽  
M. Coleman ◽  
M. Valtonen
Keyword(s):  
Surface Brightness ◽  
Elliptical Galaxies ◽  
Brightness Fluctuation ◽  
Dwarf Elliptical Galaxies

scholarly journals X-ray diagnostics of almost transparent Fe plasma of inverted corona target

1999 ◽  
Vol 17 (2) ◽  
pp. 293-298
Author(s):  
A.V. BESSARAB ◽  
S.A. BEL'KOV ◽  
P.D. GASPARYAN ◽  
N.V. ZHIDKOV ◽  
A.V. KUNIN ◽  
...  
Keyword(s):  
Experimental Data ◽  
Laser Radiation ◽  
Total Energy ◽  
Resonance Line ◽  
X Ray ◽  
Calculation Results

Measurements of spectral and energy X-ray characteristics of almost transparent Fe plasma produced by laser radiation inside the inverted-corona targets have been made at ISKRA-5 facility. The targets were spherical plastics cavities with 2-mm diameter and 4.6-μm thickness covered from inside with Fe layer 0.25-μm thickness. X-ray spectrum, X-ray total energy, and the energy of a HeαFe resonance line have been measured. Experimental data and calculation results are collated.

scholarly journals Alternatives to the Existence of Large Cooling Flows

1990 ◽  
Vol 115 ◽  
pp. 232-239
Author(s):  
Wallace Tucker
Keyword(s):  
Surface Brightness ◽  
Large Scale ◽  
Theoretical Calculations ◽  
Central Peak ◽  
High Energy ◽  
Cooling Time ◽  
Radiative Cooling ◽  
Massive Black Hole ◽  
X Ray ◽  
Cooling Flows

AbstractArguments against the existence of large scale cooling flows in clusters of galaxies are presented. The evidence for cooling flows is all circumstantial, consisting of observations of cool gas or hot gas with a radiative cooling time less than the Hubble time, or a central peak in the x-ray surface brightness profile. There is no evidence for large quantities (several tens to several hundreds of solar masses per year) of matter actually flowing anywhere. On the contrary, several lines of evidence — stellar dynamics, observations of the amount of star formation, x-ray surface brightness observations, theoretical calculations of the growth of thermal instabilities, the amount of cold gas — suggest that cooling flows, if they exist, must be suppressed by one to two orders of magnitude from the values implied by simple estimates based on the radiative cooling time of the x-ray emitting gas. Two heat sources which might accomplish this — thermal conduction and relativistic particles, are considered and an alternative to the standard model for cooling flows is presented: an accretion flow with feedback wherein the accretion of gas into a massive black hole in the central galaxy generates high energy particles that heat the gas and act to limit the accretion.

scholarly journals X-ray Interferometry

2001 ◽  
Vol 205 ◽  
pp. 457-462
Author(s):  
Webster Cash
Keyword(s):  
Black Hole ◽  
Event Horizon ◽  
Surface Brightness ◽  
High Surface ◽  
X Rays ◽  
High Surface Brightness ◽  
X Ray

X-rays have tremendous potential for imaging at the highest angular resulution. The high surface brightness of many x-ray sources will reveal angular scales heretofore thought unreachable. The short wavelengths make instrumentation compact and baselines short. We discuss how practical x-ray interferometers can be built for astronomy using existing technology. We describe the Maxim Pathfinder and Maxim missions which will achieve 100 and 0.1 micro-arcsecond imaging respectively. The science to be tackled with resolution of up to one million times that of HST will be outlined, with emphasis on eventually imaging the event horizon of a black hole.

scholarly journals Photometric and kinematic properties of disky elliptical galaxies

1993 ◽  
Vol 153 ◽  
pp. 425-426
Author(s):  
Cecilia Scorza
Keyword(s):  
Fourier Expansion ◽  
Major Axis ◽  
Elliptical Galaxies ◽  
Continuous Transition ◽  
X Ray ◽  
Hubble Sequence ◽  
Kinematic Properties

New insights in the structure of elliptical galaxies have been obtained indicating the presence of faint stellar disks in some of these systems. Clear correlations between the isophotal shapes, the kinematic, radio and X-ray properties of disky E's were found, suggesting that these galaxies form together with SO's a continuous transition of D/B ratio in the Hubble sequence (Bender et al. 1989). The isophotal shapes of these galaxies have been quantified by the fourth cosine coefficient a4 of the Fourier expansion of the deviations from perfect ellipses, which yields positive values when the isophotes are pointed along the major axis (Carter 1987, Lauer 1985, Jedrzewski 1987, Bender and Möllenhoff 1987).

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