scholarly journals A Survey of the Interstellar Medium in Elliptical Galaxies: the Ionized Gas

1996 ◽  
Vol 171 ◽  
pp. 348-348
Author(s):  
N. Caon ◽  
F. Macchetto ◽  
M. Pastoriza
Keyword(s):  
Large Fraction ◽  
Broad Band ◽  
Elliptical Galaxies ◽  
Ionized Gas ◽  
X Ray ◽  
Lenticular Galaxies ◽  
The Galaxy ◽  
Extensive Program ◽  
Galaxy Center ◽  
S0 Galaxies

We have carried out an extensive program of observations of the ionized gas in 74 luminous elliptical and lenticular galaxies, selected to include a variety of properties in radio and X-ray emission, and in kinematical behavior. For each galaxy we have obtained broad-band R and V images and narrow-band images, centered at the Hα and [NII] emission lines, to derive the luminosity and distribution of the ionized gas. We found that a large fraction (≃ 70%) of E and S0 galaxies in our sample contain ionized gas. The gas morphology and size varies from small disks (mean diameter 1 – 4 kpc) to large filamentary structures (extending up to 10 kpc from the galaxy center). Comparison with previous measurements shows reasonable agreement for a few galaxies, but considerable scatter for a large fraction, possibly due to differences in the limiting flux thresholds.

scholarly journals Metal Abundances in the Hot ISM of Elliptical Galaxies

1998 ◽  
Vol 188 ◽  
pp. 53-56
Author(s):  
M. Loewenstein ◽  
R. F. Mushotzky
Keyword(s):  
Spectral Analysis ◽  
Spatial Distribution ◽  
Galaxy Formation ◽  
Formation Process ◽  
Total Mass ◽  
Broad Band ◽  
Elliptical Galaxies ◽  
X Ray ◽  
The Galaxy ◽  
Metal Abundances

In elliptical galaxies, where most of the stars were formed at an early epoch, the total mass, spatial distribution, and relative abundances of metals are intimately connected to the galaxy formation process. Determinations of the hot interstellar medium metallicity from X-ray spectral analysis are more direct, less model-dependent, and more radially extensive than optical estimates based on broad-band colors or line indices, and provide a view into the nucleosynthetic histories of elliptical galaxies.

scholarly journals LINER-like emission in red galaxies: evolutionary phase or recurring phenomenon?

2007 ◽  
Vol 3 (S245) ◽  
pp. 181-184
Author(s):  
Genevieve J. Graves
Keyword(s):  
Stellar Population ◽  
Velocity Dispersion ◽  
Large Fraction ◽  
Optical Emission ◽  
Ionized Gas ◽  
Satellite Galaxy ◽  
The Galaxy ◽  
Evolutionary Phase ◽  
Interstellar Material ◽  
Red Galaxies

AbstractWe present recent results showing that a large fraction of red sequence galaxies contain ionized gas with LINER-like optical emission line ratios. This emission is more frequently found in galaxies with lower central velocity dispersion (σ) and these galaxies typically have younger mean ages than galaxies at the same σ which do not host emission. We suggest that the presence of LINER-like emission may be determined by the quantity of interstellar material in these galaxies and may be associated with the recent accretion of a gas-rich satellite galaxy or alternatively with stellar mass loss that declines as the galaxy stellar population ages.

scholarly journals A Spiral-Like Disk of Ionized Gas in IC 1459: Signature of a Merging Collision?

1990 ◽  
Vol 124 ◽  
pp. 215-219
Author(s):  
Paul Goudfrooij ◽  
H.U. Nørgaard-Nielsen ◽  
H.E. Jørgensen ◽  
L. Hansen ◽  
T. de Jong
Keyword(s):  
Spiral Structure ◽  
Elliptical Galaxy ◽  
Broad Band ◽  
Major Axis ◽  
Colour Index ◽  
Line Flux ◽  
Ionized Gas ◽  
The Galaxy ◽  
Merger Event ◽  
Stellar Body

AbstractWe report the discovery of a large (15 kpc diameter) Hα+[NII] emission-line disk in the elliptical galaxy IC 1459, showing weak spiral structure. The line flux peaks strongly at the nucleus and is more concentrated than the stellar continuum. The major axis of the disk of ionized gas coincides with that of the stellar body of the galaxy. The mass of the ionized gas is estimated to be ~ 1 105 M⊙, less than 1% of the total mass of gas present in IC 1459. The total gas mass of 4 107 M⊙ has been estimated from the dust mass derived from a broad-band colour index image and the IRAS data. We speculate that the presence of dust and gas in IC 1459 is a signature of a merger event.

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.

scholarly journals The X-ray emission of E and S0 Galaxies

1996 ◽  
Vol 171 ◽  
pp. 123-130
Author(s):  
G. Fabbiano
Keyword(s):  
Gravitational Mass ◽  
X Ray ◽  
Cooling Flows ◽  
The Galaxy ◽  
Metal Abundance ◽  
S0 Galaxies

It is well known by now that E and S0 galaxies are associated with hot, X-ray emitting gaseous halos, subject to central cooling flows, but otherwise homogeneous, which can be used to trace the galaxy potential and thus measure the total gravitational mass. Recent ASCA observations suggest that these halos have a surprisingly low metal abundance.

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.

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 Galaxy properties as revealed by MaNGA – I. Constraints on IMF and M*/L gradients in ellipticals

2019 ◽  
Vol 489 (4) ◽  
pp. 5612-5632 ◽  
Author(s):  
H Domínguez Sánchez ◽  
M Bernardi ◽  
J R Brownstein ◽  
N Drory ◽  
R K Sheth
Keyword(s):  
Stellar Population ◽  
Companion Paper ◽  
Elliptical Galaxies ◽  
Element Abundance ◽  
Galactocentric Distance ◽  
Massive Galaxies ◽  
The Galaxy ◽  
Central Regions ◽  
S0 Galaxies ◽  
Mass Functions

ABSTRACT We estimate ages, metallicities, α-element abundance ratios, and stellar initial mass functions (IMFs) of elliptical (E) and S0 galaxies from the MaNGA-DR15 survey. We stack spectra and use a variety of single stellar population synthesis models to interpret the absorption line strengths in these spectra. We quantify how these properties vary across the population, as well as with galactocentric distance. This paper is the first of a series and is based on a sample of pure elliptical galaxies at z ≤ 0.08. We confirm previous work showing that IMFs in Es with the largest luminosity (Lr) and central velocity dispersion (σ0) appear to be increasingly bottom heavy towards their centres. For these galaxies the stellar mass-to-light ratio decreases at most by a factor of 2 from the central regions to Re. In contrast, for lower Lr and σ0 galaxies, the IMF is shallower and M*/Lr in the central regions is similar to the outskirts, although quantitative estimates depend on assumptions about element abundance gradients. Accounting self-consistently for these gradients when estimating both M* and Mdyn brings the two into good agreement: gradients reduce Mdyn by ∼0.2 dex while only slightly increasing the M* inferred using a Kroupa IMF. This is a different resolution of the M*–Mdyn discrepancy than has been followed in the recent literature where M* of massive galaxies is increased by adopting a Salpeter IMF throughout the galaxy while leaving Mdyn unchanged. A companion paper discusses how stellar population differences are even more pronounced if one separates slow from fast rotators.

scholarly journals The Nature of the Dusty Ionized Gas in NGC 5846: (And Other Elliptical Galaxies ?)

1999 ◽  
Vol 186 ◽  
pp. 199-199
Author(s):  
Paul Goudfrooij ◽  
Ginevra Trinchieri
Keyword(s):  
Elliptical Galaxy ◽  
Elliptical Galaxies ◽  
Ionized Gas ◽  
Full Account ◽  
Optical Extinction ◽  
X Ray ◽  
Cooling Flow ◽  
Hot Gas ◽  
Optical Imagery ◽  
Astronomy And Astrophysics

We present new optical imagery and ROSAT HRI X-ray imagery of the elliptical galaxy NGC 5846. A filamentary dust lane is detected in its central region, with a morphology strikingly similar to that observed for the optical nebulosity and the X-ray emission (cf. Fig. 1). A physical connection between the different phases of the interstellar medium therefore seems likely. The energy deposited from the hot gas into heating of the dust grains is consistent with the temperature distribution of the X-ray-emitting gas, which is found to be lowest in the dusty regions. The optical extinction of the dust is consistent with the Galactic extinction curve. We argue that the dust as well as the optical nebulosity are products of an interaction with a small, gas-rich galaxy, not remnants of a cooling flow. A full account of this work is currently in press in Astronomy and Astrophysics, and a preprint is available through http://www.stsci.edu/science/preprints/prep1191/prep1191.html.

scholarly journals BL Lac Objects and Their Associated Galaxies

1982 ◽  
Vol 97 ◽  
pp. 377-382 ◽  
Author(s):  
Donna Weistrop
Keyword(s):  
Point Source ◽  
Small Group ◽  
Lower Limit ◽  
Elliptical Galaxies ◽  
Synchrotron Emission ◽  
Ccd Photometry ◽  
Bl Lac Objects ◽  
X Ray ◽  
Bl Lac ◽  
The Galaxy

CCD photometry of five BL Lac objects indicates that at least three, and possibly four, are located at the centers of giant elliptical galaxies. The redshift for one of these objects, 1218+304, is estimated. A lower limit is placed on the redshift of 1219+28, for which no associated galaxy has been detected. Separation of the galaxy emission from the total observed flux makes possible comparison of the optical — far red flux from the point source alone with radio and X-ray data. This comparison suggests the emission from 1727+50 and 1218+304 can be interpreted as due to direct synchrotron emission. Observations of a small group of galaxies associated with the BL Lac object 1400+162 are also discussed.

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