ﻻ يوجد ملخص باللغة العربية
Analysis of spatially resolved ASCA spectra of the intracluster gas in Abell 496 confirms that metal abundances increase toward the center. We also find spatial gradients in several abundance ratios, indicating that the fraction of iron from SN Ia increases toward the cluster center. The dominant metal enrichment mechanism near the cluster center must therefore be different than in the outer parts. We show that ram pressure stripping of gas from cluster galaxies cannot account for the central abundance enhancement. We suggest that two successive stages of galactic winds contaminate intracluster gas: protogalactic winds driven by SN II, followed by less energetic winds driven by SN Ia, which have longer lived progenitors than SN II. The less energetic secondary wind from a cD galaxy may be suppressed, due to its location at the cluster center, leading to the observed central enhancement of SN Ia ejecta.
Analysis of spatially resolved ASCA spectra of the intracluster gas in Abell 496 confirms there are mild metal abundance enhancements near the center, as previously found by White et al. (1994) in a joint analysis of Ginga LAC and Einstein SSS spectr
It has recently been suggested that galaxies in the early Universe can grow through the accretion of cold gas, and that this may have been the main driver of star formation and stellar mass growth. Because the cold gas is essentially primordial, it h
We use the EAGLE simulations to study the oxygen abundance gradients of gas discs in galaxies within the stellar mass range [10^9.5, 10^10.8]Mo at z=0. The estimated median oxygen gradient is -0.011 (0.002) dex kpc^-1, which is shallower than observe
The pace and pattern of star formation leading to rich young stellar clusters is quite uncertain. In this context, we analyze the spatial distribution of ages within 19 young (median t<3 Myr on the Siess et al. (2000) timescale), morphologically simp
We present here the second part of a project that aims at solving the controversy on the issue of the bar effect on the radial distribution of metals in the gas-phase of spiral galaxies. In Paper I we presented a compilation of more than 2800 HII reg