AST 111 Lecture Notes - Lecture 10: Tunxis Community College, Irregular Galaxy, Blauw-Wit Amsterdam
18 Dec 2020
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Document Summary
Cosmology is the study of the structure and evolution of the universe; this is connected with the study of galaxies, as the galaxy"s age and distance is related to the age of the universe. Three types of galaxies: spiral, elliptical and irregular. Elliptical galaxies = all spheroidal component with virtually no disk component, red-yellow colour indicates an older star population, often found in clusters of galaxies (100s to 1000s of galaxies) Irregular galaxies = no concrete shape; blue-white colour indicates ongoing star formation. E0, e5 are spheroidal; s0 and sb0 are lenticular; sc/sbc to sb/sbb to sa/sba gives larger bulge, less dusty gas, tighter spiral arms. Galaxies fall into two groups blue cloud and red sequence. To summarize: galaxies generally formed when the universe was young and have aged along with the universe, gas and dust are more abundant in spiral and irregular galaxies than in elliptical galaxies. We can measure the distance to galaxies .
