scholarly journals Evolution of the Coronae in Early-Type Galaxies

1990 ◽  
Vol 115 ◽  
pp. 240-244
Author(s):  
L.P. David ◽  
W. Forman ◽  
C. Jones
Keyword(s):  
Mass Loss ◽  
Numerical Simulations ◽  
Elliptical Galaxies ◽  
Compact Groups ◽  
Type I ◽  
Dark Halo ◽  
Early Type ◽  
X Ray ◽  
Galactic Winds ◽  
The Galaxy

AbstractWe present numerical simulations of the gaseous coronae in elliptical galaxies. These models consist of a modified King profile for the luminous portion of the galaxy and an isothermal dark halo. We include evolving stellar mass loss from planetary nebulae, and type I and II supernovae. Our models show that elliptical galaxies are likely to produce strong galactic winds at early times with x-ray luminosities of 1042 — 1044 ergs s-1 and temperatures of 10 keV. Galaxies can lose approximately 10-30% of their initial luminous mass in the wind which has an oxygen-to-iron ratio twice the solar value. Since elliptical galaxies are a principle component of rich clusters and compact groups this early wind phase affects the metallicity and temperature of the intracluster medium.

scholarly journals X-Rays from Elliptical Galaxies

1987 ◽  
Vol 127 ◽  
pp. 155-165
Author(s):  
A.C. Fabian ◽  
P.A. Thomas
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Mass Loss ◽  
Elliptical Galaxies ◽  
Stellar Mass ◽  
X Rays ◽  
Early Type ◽  
X Ray ◽  
Isolated Galaxies

X-ray observations have shown that early-type galaxies contain a hot interstellar medium. This implies that the galaxies have a) a low supernova rate; b) high total gravitational binding masses and c) continuous star formation. Much of the gas in isolated galaxies is probably due to stellar mass-loss. The details of its behaviour are complex.

Supermassive Black Hole feedback in early type galaxies

2020 ◽  
Vol 15 (S359) ◽  
pp. 119-125
Author(s):  
W. Forman ◽  
C. Jones ◽  
A. Bogdan ◽  
R. Kraft ◽  
E. Churazov ◽  
...  
Keyword(s):  
Dark Matter Halo ◽  
Scaling Relations ◽  
Radio Sources ◽  
Early Type ◽  
X Ray ◽  
Galaxy Groups ◽  
Sufficient Energy ◽  
The Galaxy ◽  
Simple Scaling ◽  
Halo Masses

AbstractOptically luminous early type galaxies host X-ray luminous, hot atmospheres. These hot atmospheres, which we refer to as coronae, undergo the same cooling and feedback processes as are commonly found in their more massive cousins, the gas rich atmospheres of galaxy groups and galaxy clusters. In particular, the hot coronae around galaxies radiatively cool and show cavities in X-ray images that are filled with relativistic plasma originating from jets powered by supermassive black holes (SMBH) at the galaxy centers. We discuss the SMBH feedback using an X-ray survey of early type galaxies carried out using Chandra X-ray Observatory observations. Early type galaxies with coronae very commonly have weak X-ray active nuclei and have associated radio sources. Based on the enthalpy of observed cavities in the coronae, there is sufficient energy to “balance” the observed radiative cooling. There are a very few remarkable examples of optically faint galaxies that are 1) unusually X-ray luminous, 2) have large dark matter halo masses, and 3) have large SMBHs (e.g., NGC4342 and NGC4291). These properties suggest that, in some galaxies, star formation may have been truncated at early times, breaking the simple scaling relations.

scholarly journals The properties of early-type stars in the Magellanic Clouds

2008 ◽  
Vol 4 (S256) ◽  
pp. 325-336
Author(s):  
Christopher J. Evans
Keyword(s):  
Physical Properties ◽  
Mass Loss ◽  
Temperature Scale ◽  
Massive Stars ◽  
Magellanic Clouds ◽  
Early Type ◽  
The Past ◽  
The Galaxy ◽  
Stellar Temperature ◽  
Early Type Stars

AbstractThe past decade has witnessed impressive progress in our understanding of the physical properties of massive stars in the Magellanic Clouds, and how they compare to their cousins in the Galaxy. I summarise new results in this field, including evidence for reduced mass-loss rates and faster stellar rotational velocities in the Clouds, and their present-day compositions. I also discuss the stellar temperature scale, emphasizing its dependence on metallicity across the entire upper-part of the Hertzsprung-Russell diagram.

scholarly journals X-Ray Observations of Elliptical Galaxies by ASCA Satellite

1996 ◽  
Vol 171 ◽  
pp. 412-412
Author(s):  
K. Matsushita ◽  
K. Makishima
Keyword(s):  
Low Temperature ◽  
Mass Loss ◽  
Elliptical Galaxies ◽  
Stellar Mass ◽  
Plasma Emission ◽  
X Ray ◽  
Theoretical Predictions ◽  
Long Time ◽  
Temperature Component ◽  
Hubble Time

Using ASCA, we have confirmed that the ISM of X-ray bright elliptical galaxies are surprisingly metal poor, as compared to the theoretical predictions. In fact the exact values of the derived metallicity depend considerably on the plasma emission codes. However, the overall metallicity cannot be larger than ∼ 1 solar. For low LX/LB galaxies, all the available plasma codes suggest abundances less than half a solar. The ASCA spectra may be compatible with somewhat higher metallicity if we assume there is an additional low-temperature component (e.g. kTe ∼ 0.3 keV). However, the derived abundance can not be over 1 solar. In particular, the Si abundance turns out to be < 1.5 solar, confirming the metal-poor nature of the ISM. These ASCA results are in severe contradiction with most of the SN Ia rate, particularly that of Tammann (1982). Considering further that a fairly long time (109–10yr) is needed for the stellar mass loss to accumulates into the ISM, it is suggested that the SN Ia rate has remained quite low throughout Hubble time.

scholarly journals The Dark Halo – Spheroid Conspiracy

2012 ◽  
Vol 8 (S295) ◽  
pp. 208-208
Author(s):  
Rhea-Silvia Remus ◽  
Andreas Burkert ◽  
Klaus Dolag ◽  
Peter H. Johansson ◽  
Thorsten Naab ◽  
...  
Keyword(s):  
Elliptical Galaxies ◽  
Total Density ◽  
Dark Halo ◽  
Coma Cluster ◽  
Density Profiles ◽  
Stellar Component ◽  
Strong Lensing ◽  
The Galaxy ◽  
Good Agreement

AbstractObservational results from strong lensing and dynamical modeling indicate that the total density profiles of early-type galaxies are close to isothermal, i.e. ρtot ∝ rγ with γ ≈ −2. To understand the origin of this universal slope we study a set of simulated spheroids formed in cosmological hydrodynamical zoom-in simulations (see Oser et al. 2010 for more details). We find that the total stellar plus dark matter density profiles of all our simulations on average can be described by a power law with a slope of γ ≈ −2.1, with a tendency towards steeper slopes for more compact, lower mass ellipticals, while the total intrinsic velocity dispersion is flat for all simulations, independent of the values of γ. Our results are in good agreement with observations of Coma cluster ellipticals (Thomas et al. 2007) and results from strong lensing (Sonnenfeld et al. 2012). We find that for z ≳ 2 the majority of the stellar build-up occurs through in-situ star formation, i.e. the gas falls to the center of the galaxy and forms stars, causing the galaxy to be more compact and thus the stellar component to be more dominant. As a result, the total density slopes at z ≈ 2 are generally steeper (around γ ≈ −3). Between z = 2 and z = 0 galaxies grow mostly through dry merging, with each merging event shifting the slope more towards γ ≈ −2. We conclude from our simulations that the steepness of the slope of present day galaxies is a signature of the importance of mostly dry mergers in the formation of an elliptical, and suggest that all elliptical galaxies will with time end up in a configuration with a density slope of γ ≈ −2. For a more detailed analysis with a larger sample of simulations see Remus et al. (2013).

scholarly journals Metal-Enhanced Galactic Winds

1987 ◽  
Vol 127 ◽  
pp. 435-436
Author(s):  
J. Patricia Vader
Keyword(s):  
Star Formation ◽  
Mass Loss ◽  
Dwarf Galaxies ◽  
Elliptical Galaxies ◽  
Potential Well ◽  
Metal Production ◽  
Galactic Winds ◽  
Important Constraint

Constraints on supernova-driven galactic winds from elliptical galaxies at the epoch of star formation are investigated. The occurrence of mass loss is found to depend critically on the supernova rate in the case of dwarf galaxies, while the depth of the potential well is the most important constraint for giant ellipticals. The smallest dwarf ellipticals must have evolved from significantly more massive progenitors in order to have sustained a wind that carried away most of their metal production.

scholarly journals The Galaxy Merger Origin of Hot Gaseous Halos of Ellipticals

2004 ◽  
Vol 217 ◽  
pp. 412-417
Author(s):  
X. Y. Xia ◽  
Z. Y. Huo ◽  
S. J. Xue
Keyword(s):  
Central Region ◽  
Elliptical Galaxies ◽  
Emission Lines ◽  
Central Nucleus ◽  
Nuclear Region ◽  
Feedback Process ◽  
X Ray ◽  
The Galaxy ◽  
Low Metallicity ◽  
Gaseous Halo

We report on the properties of the hot gaseous halos of 10 nearby ultraluminous IRAS galaxies from Chandra observations. There exists diffuse soft X-ray emission surrounding the central nucleus within 10 kpc of the nuclear region with a temperature of about 0.7 keV and metallicity about Z ~ 1.0Z⊙. Also, emission lines from α elements and ions for are seen in all nearby ULIRGs in our sample. Outside the central region, the Chandra observations reveal a more extended hot gaseous halo with a temperature of about 0.6 keV and low metallicity (Z ~ 0.1Z⊙) for some of the ULIRGs. We discuss the nature and the implications of our results for the origin of X-ray halos in elliptical galaxies and the constraints this places on the feedback process.

Parameters for Dark Halos

1987 ◽  
Vol 117 ◽  
pp. 119-132 ◽  
Author(s):  
K. C. Freeman
Keyword(s):  
Elliptical Galaxies ◽  
Disk Galaxies ◽  
Dark Halo ◽  
Characteristic Scale ◽  
Rotation Curves ◽  
X Ray ◽  
Unique Information ◽  
Best Estimates

What are the characteristic scale lengths and densities for the dark halos of galaxies, and the typical ratios of dark to luminous mass? For elliptical galaxies, the best estimates come from X-ray data which will be discussed in a later session. For spirals, the best estimates come from rotation curves. I will concentrate on the halo parameters for disk galaxies. At the end, there will be a few comments on stellar dynamical data for ellipticals, and on the unique information available for the dark halo of our Galaxy.

scholarly journals The O stars: optical review

1979 ◽  
Vol 83 ◽  
pp. 1-22
Author(s):  
J. B. Hutchings
Keyword(s):  
Neutron Star ◽  
Interstellar Medium ◽  
Mass Loss ◽  
Large Fraction ◽  
Significant Fraction ◽  
High Mass ◽  
X Ray ◽  
The Galaxy ◽  
High Mass Loss ◽  
Rough Outline

I would like to start with a quick overview of the O stars - their significance and role in the galaxy and in astrophysics - just to remind ourselves of why we are here and what we hope to talk about. In Table 1 I show a rough outline of the contribution of O stars to what happens in the galaxy as a whole. Because of their extreme luminosity, they contribute a large fraction of the radiation of the galaxy, while forming a very tiny group of objects and mass. Because of their short lifetime they are a population that has gone through 104 generations in the life of the galaxy. Their high mass loss rates may account for a large fraction of the new matter injected into the interstellar medium, and they probably power some significant fraction of the hard X-ray sources in the galaxy, by virtue of the fact that a companion can become a neutron star a) without disrupting the binary and b) while the companion is still a mass losing O star.

Mass Loss and Stellar Wind in Massive X-Ray Binaries

1980 ◽  
Vol 5 ◽  
pp. 541-547
Author(s):  
H. F. Henrichs
Keyword(s):  
Mass Loss ◽  
Stellar Wind ◽  
Binary Systems ◽  
Massive Stars ◽  
Compact Star ◽  
X Rays ◽  
Early Type ◽  
X Ray ◽  
X Ray Binaries ◽  
Loss Rates

A number of massive stars of early type is found in X-ray binary systems. The catalog of Bradt et al. (1979) contains 21 sources optically identified with massive stars ranging in spectral type from 06 to B5 out of which 13 are (nearly) unevolved stars and 8 are supergiants. Single stars of this type generally show moderate to strong stellar winds. The X-rays in these binaries originate from accretion onto a compact companion (we restrict the discussion to this type of X-rays).We consider the compact star as a probe traveling through the stellar wind. This probe enables us to derive useful information about the mass outflow of massive stars.After presenting the basic data we derive an upper limit to mass loss rates of unevolved early type stars by studying X-ray pulsars. Next we consider theoretical predictions concerning the influence of X-rays on the stellar wind and compare these with the observations. Finally, using new data from IUE, we draw some conclusions about mass loss rates and velocity laws as derived from X-ray binaries.

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