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Definition
| a galaxy whose shape is an ellipse and that contains no conspicuous interstellar material |
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| a constant of proportionality in the law relating the velocities of remote galaxies to their distances |
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| a rule that the radial velocities of remote galaxies are proportional to their distances from us |
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| a galaxy without any clear symmetry or pattern; neither a spiral nor an elliptical galaxy |
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| the ratio of the total mass of a galaxy to its total luminosity, usually expressed in units of solar mass and solar luminosity; the mass-to-light ratio gives a rough indication of the types of stars contained within a galaxy and whether or not substantial quantities of dark matter are present |
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| when lines in the spectra are displaced toward longer wavelengths (toward the red end of the visible spectrum) |
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| a flattened, rotating galaxy with pinwheel-like arms of interstellar material and young stars, winding out from its central bulge |
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| a supernova formed by the explosion of a white dwarf in a binary system and reach a luminosity of about 4.5 × 109 LSun; can be used to determine distances to galaxies on a large scale |
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