The surface brightness-axis ratio relation as a test of intrinsic shapes of elliptical galaxies

1981 ◽  
Vol 249 ◽  
pp. 68 ◽  
Author(s):  
D. W. Olson ◽  
G. de Vaucouleurs
2001 ◽  
Vol 380 (1) ◽  
pp. 90-101 ◽  
Author(s):  
H. Jerjen ◽  
R. Rekola ◽  
L. Takalo ◽  
M. Coleman ◽  
M. Valtonen

1983 ◽  
Vol 100 ◽  
pp. 295-296
Author(s):  
Gary A. Mamon

Giant elliptical galaxies are now known to be supported by anisotropic pressure rather than by rotation (cf. Binney, 1981). This anisotropy can be derived from observable quantities for spherical systems as was shown by Binney and Mamon (1982) in their study of M87. We investigate here the velocity anisotropy of the El galaxy NGC 3379, a giant elliptical whose surface brightness constitutes an excellent illustration of the r1/4 law.


1987 ◽  
Vol 127 ◽  
pp. 79-88
Author(s):  
S. Djorgovski

Global properties of elliptical galaxies, such as the luminosity, radius, projected velocity dispersion, projected luminosity density, etc., form a two-dimensional family. This “fundamental plane” of elliptical galaxies can be defined by the velocity dispersion and mean surface brightness, and its thickness is presently given by the measurement error-bars only. This is indicative of a strong regularity in the process of galaxy formation. However, all morphological parameters which describe the shape of the distribution of light, and reflect dynamical anisotropies of stars, are completely independent from each other, and independent of the fundamental plane. The M/L ratios show only a small intrinsic scatter in a luminosity range spanning some four orders of magnitude; this suggests a constant fraction of the dark matter contribution in elliptical galaxies.


2006 ◽  
Vol 2 (S235) ◽  
pp. 280-283
Author(s):  
Crystal L. Martin

Major mergers of gas-rich galaxies, each comparable in mass to the Milky Way, are rare at the present epoch. These events were readily identifed, however, two decades ago in far-infrared sky surveys (Soifer et al. 1986, 1987). Removal of the dust enshrouding these starbursts was almost immediately proposed as an evolutionary path to quasar formation (Sanders 1988). Recent measurements of the stellar velocity dispersion, rotation speed, and stellar surface brightness profile of these mergers suggest ULIRGs are indeed progenitors of field elliptical galaxies (Genzel et al. 2001; Tacconi et al. 2002).


1983 ◽  
Vol 6 ◽  
pp. 187-190
Author(s):  
Sidney van den Bergh

Men are more apt to be mistaken in their generalization than in their particular observations. MachiavelliIt was already realized by Hubble (1936) that galaxy morphology and stellar content were correlated. He pointed out that resolution into stars increases along the classification sequence Sa-Sb-Sc. Simultaneously the colours of spirals become bluer and their integrated spectral types become earlier as one proceeds from Sa to Sc. Baade (1944) speculated that the red stars in ellipticals and in the nuclear bulges of spirals were identical to those in globular clusters. He suggested that stars in galaxies belong to two distinct populations: young metal-rich stars of Population I which inhabit the disc and spiral arm regions of spirals, and old metal-poor stars of Population II which dominate the light of elliptical galaxies and the nuclear bulges of spirals. Subsequently Baade (1950) emphasized the strong correlation between the occurrence of gas and dust and the presence of young stars. As Baade put it so succinctly “No dust, no Population I”. Belief in a clear cut dichotomy between Population I and Population II was strengthened by the differences in their radial luminosity distributions. The surface brightness of Population I in spirals is well represented by an exponential disc, whereas the surface brightness of Population II stars in ellipticals and the bulges of spirals may be described by an r1/4 law (de Vaucouleurs 1959).


1987 ◽  
Vol 127 ◽  
pp. 507-508
Author(s):  
A. Kashlinsky

Distribution functions containing cutoff in energy impose several limitations on systems they describe, e.g., no circular orbits are allowed in the major part of system and spatial boundary is poorly defined. As opposed to these functions, we present here distribution function that describes galaxies of finite extent (i.e., truncated in radius). We discuss properties of systems having this distribution function for spherical and axisymmetric cases and compare their surface brightness, isophotes, and rotation curves with observations of elliptical galaxies. This distribution function can easily be generalized to a triaxial galaxy.


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