As a single stellar population evolves, the rate of dusty mass loss from red giant stars decreases with time, so the mid-infrared luminosity should also decline with stellar age. To seek such a correlation, we have used archival Infrared Space Observatory (ISO) observations to determine surface...
The radiative cooling time of hot gas in the cool cores of many galaxy clusters and massive elliptical galaxies drops in the centre to below 108 yr. The mass cooling rates inferred from simple modelling of X-ray observations of these objects are very low, indicating that either active ...
哈勃音叉图 (1)椭圆星系(Elliptical galaxies) 椭球形的星系,符号为E. 按椭率大小的增加分为E0、 E1...E7八个次型。 n=10(a-b… wenku.baidu.com|基于82个网页 2. 椭圆银河系 椭圆银河系(Elliptical Galaxies):显现於吾人视线上的外表为椭圆的形状,由略近圆形而至长椭圆形,用英文字母「E」表示 … ...
Radially anisotropic models need a low stellar mass-to-light ratio, which would contrast with the old age of the galaxy. A MONDian model is supported by X-ray analysis and previous dynamical modelling, but better data are necessary for a confirmation. The dwarf companion galaxy NGC 7796-1 ...
In a sample of elliptical galaxies that span a large range of mass, a previously unused Ca index, CaHK, shows that [Ca/Fe] and [Ca/Mg] systematically decrease with increasing elliptical galaxy mass. Metallicity mixtures, age effects, stellar chromospheric emission effects, and low-mass initial...
Spiral Elliptical Irregular then further breaks them down by specific characteristics (openness of spirals, size and extent of bars, size of galactic bulges). In this age of multi-wavelength observing, the sub-classifications also include markers for such characteristics as a galaxy’s star-formatio...
Stellarageinanellipticalgalaxyhasbeenmeasuredandtherearenowahandfulofelliptical galaxieswithintermediatestellarage(<5Gyr)whichcouldlinkbetweenAntennae-likemerging systemsandtypicaloldellipticalgalaxies(e.g,.Thomasetal.2005).Wefindthatyoungelliptical galaxieshostmoreluminous(>5×10 ...
S1 ← S0 transition of phenylacetylene ab initio and resonant two-photon ionization studies 热度: a r X i v : a s t r o - p h / 0 1 0 8 2 1 2 v 1 1 3 A u g 2 0 0 1 ApJ,inpress AgesofS0andellipticalgalaxiesintheComacluster ...
Methods. We studied physical properties of ellipticals, such as color, specific star formation rate, galaxy size, and stellar age, as a function of stellar mass and environment based on SDSS data. We analyzed the blue and star-forming isolated ellipticals in more detail, through photometric ...
After that, star formation proceeded at a low rate until the recent past, the age of the most recent traces of star formation activity detected in the galaxy being some 100 Myr. As for the spatial variations, the star formation rates, 蠄(t), for old and intermediate-age stars show a ...