Term
| Properties of an active galaxy include |
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Definition
| powerful X-ray and radio emission from its core, presence of a supermassive black hole, and spectra of the core implying hot gas moving at high speeds. |
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Term
| What is considered an active galaxy? |
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Definition
| Seyfert galaxies, Radio galaxies, quasars and blazars |
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Term
| _____ galaxies are the most common type of galaxies in the Universe |
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Definition
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Term
| _______ are the most massive galaxies in the Universe's |
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Definition
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Definition
| mostly young stars, dust and gas in their spiral |
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Term
| Elliptical galaxies contain |
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Definition
| no gas and dust and mostly old stars |
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Term
| How do we know that quasars are distant objects in the Universe? |
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Definition
| Their spectrum shows a very high redshift. |
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Term
| Given that quasars are so far away, what can we conclude about their power output? |
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Definition
| They must be very luminous to be visible at such great distances. |
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Term
| What type of galaxy contains arms and a central bulge? |
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Definition
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Term
| Centers of almost all galaxies contain |
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Definition
| A supermassive black hole |
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Term
| A galaxy that has no defined shape is called |
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Definition
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Term
| Starburst galaxies are formed due to |
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Definition
| Mergers of two or more galaxies |
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Term
| Redshift of a galaxy indicates its |
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Definition
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Term
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Definition
| an empirical relationship between a galaxy's luminosity and its rotational velocity (rotation curve) |
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Definition
| a galaxy's redshift and its distance to us |
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Term
| Observations of the peak flux of a Type I supernova in a galaxy are used to measure |
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Definition
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Term
| Evidence in favor of dominant dark matter presence in clusters of galaxies comes from |
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Definition
| measurements of orbital velocities of individual galaxies in a cluster |
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Term
| Astronomers spot dark matter in other galaxies by examining |
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Definition
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Term
| Elliptical galaxies should contain 10 times more dark matter than regular (baryonic) matter because |
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Definition
| they contain hot gas that only be kept in the galaxy if its mass is 10 times greater than actually observed. |
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Term
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Definition
| an effect of bending of light as it passes near a massive object and a powerful tool to spot dark matter in galaxies and clusters of galaxies |
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