Term
| The most elongated of the elliptical galaxies are Hubble's class: |
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Definition
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Term
| Using an orbit size of 8 kpc, and a period of 225 million years, the mass of our Galaxy is found to be close to |
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Definition
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Term
| While yet unproven, the proposed WIMPS would be: |
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Definition
| massive like neutrons, but more elusive than neutrinos |
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Term
| The leading explanation for the existence of spiral arms are: |
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Definition
| passages of spiral density waves through the interstellar medium |
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Term
| The energy radiated from a typical quasar requires that its black hole accrete about: |
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Definition
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Term
| Why is the energy source of Seyfert galaxies thought to be extremely compact? |
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Definition
| they vary on rapid time scales |
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Term
| The shape of, and stars found in, elliptical galaxies of type E0 are most similar to the ________ of spiral galaxies. |
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Definition
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Term
| Quasar's spectral lines are: |
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Definition
| emission lines with large red shifts |
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Term
| When spiral galaxies do collide, the impact is greatest on their: |
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Definition
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Term
| Which of the following is true about the ages and masses of spiral and elliptical galaxies? |
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Definition
| both types are about the same age, but spirals very less in mass |
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Term
| The part of the Milky Way we are most familiar with is the: |
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Definition
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Term
| Collisions between galaxies can |
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Definition
| cause bursts of star formation as starburst galaxies |
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Term
| Which relation matches the rotation of a spiral galaxy to its luminosity? |
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Definition
| the Tully-Fisher Relation |
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Term
| When mass is accreted into a black hole, how much total mass-energy can be radiated away? |
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Definition
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Term
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Definition
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Term
| To what use do astronomers put type-I supernova? |
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Definition
| determining distances to other galaxies |
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Term
| The lensing of a distant quasar is produced by ________ of a foreground galaxy. |
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Definition
| all the normal matter and dark matter |
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Term
| Which statement about Population II is incorrect? |
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Definition
| these older stars are richer in heavier elements they have made in their cores |
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Term
| The look-back time of an object is directly related to its: |
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Definition
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Term
| Which statement about Population I is incorrect? |
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Definition
| its stars surround the galaxy in the extended halo |
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Term
| The huge lobe radio galaxy at the center of the Virgo Supercluster is |
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Definition
| M-87, a giant elliptical galaxy |
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Term
| A redshift of 2 implies a recession velocity of: |
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Definition
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Term
| The type of galaxy where we can track its motion through the intergalactic medium is a |
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Definition
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Term
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Definition
| it is a large sheet of galaxies measuring 70 Mpc by 200 Mpc |
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Term
| What would a redshift of Z = 3 imply about the velocity of the object? |
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Definition
| velocity= 88% of the speed of light |
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Term
| What two observations of an object allow for a determination of the Milky Way's mass? |
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Definition
| objects velocity and distance from the galactic center |
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Term
| Why are supermassive galaxies often found at the cores of rich galaxy clusters? |
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Definition
| they are all the result of many galactic mergers; one galaxy growing at the expense of the others |
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Term
| Not now considered a good explanation for the dark matter in the halo is |
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Definition
| clouds of cool, neutral hydrogen |
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Term
| A redshift of seven implies a galaxy is receding at .96c; use Ho = 70. km/s/Mpc to find its distance |
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Definition
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Term
Not only does the central engine of active galaxies and quasars require a black hole, ________ is also needed to
provide the energy radiated |
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Definition
| an accretion disk of matter |
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Term
| Which of these techniques has the most promise for detecting MACHOs? |
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Definition
| observing duration and intensity of gravitational lenses |
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Term
| Which two classes of objects were critical to the Shapley-Curtiss Debate of 1920? |
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Definition
| globular clusters and spiral nebulae |
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Term
| Which of these would be populated almost entirely by population II stars? |
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Definition
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Term
| Based on galactic rotation curves and cluster dynamics, we think dark matter |
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Definition
| compromises about 90% of the entire mass of the universe |
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Term
| The location of the center of the Galaxy was determined by Shapley from observations of: |
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Definition
| RR Lyrae variables in globular clusters |
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Term
| Active galaxies are having their central engines temporarily fed by what occurrence? |
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Definition
| a close interaction with a neighboring galaxy |
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Term
| Presently considered to be companions of the Milky Way are |
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Definition
| the Large and Small Magellonic Clouds, and two nearby dwarf galaxy's in Sagittarius and Canis major |
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Term
| Which of these is NOT considered a fine example of galactic collisions? |
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Definition
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Term
| In a lobe radio galaxy, the ultimate energy source for the entire galaxy is thought to reside: |
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Definition
| in the galaxy's active nucleus |
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Term
| The "aspect ratio" of thickness to width of the galactic disk is about: |
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Definition
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