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Astronomy
astronomy test questions
40
Physics
Undergraduate 1
04/06/2017

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Term
The most elongated of the elliptical galaxies are Hubble's class:
Definition
E7
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
Definition
10^11
Term
While yet unproven, the proposed WIMPS would be:
Definition
massive like neutrons, but more elusive than neutrinos
Term
The leading explanation for the existence of spiral arms are:
Definition
passages of spiral density waves through the interstellar medium
Term
The energy radiated from a typical quasar requires that its black hole accrete about:
Definition
10 solar masses
Term
Why is the energy source of Seyfert galaxies thought to be extremely compact?
Definition
they vary on rapid time scales
Term
The shape of, and stars found in, elliptical galaxies of type E0 are most similar to the ________ of spiral galaxies.
Definition
halo
Term
Quasar's spectral lines are:
Definition
emission lines with large red shifts
Term
When spiral galaxies do collide, the impact is greatest on their:
Definition
giant molecular clouds
Term
Which of the following is true about the ages and masses of spiral and elliptical galaxies?
Definition
both types are about the same age, but spirals very less in mass
Term
The part of the Milky Way we are most familiar with is the:
Definition
galactic disk
Term
Collisions between galaxies can
Definition
cause bursts of star formation as starburst galaxies
Term
Which relation matches the rotation of a spiral galaxy to its luminosity?
Definition
the Tully-Fisher Relation
Term
When mass is accreted into a black hole, how much total mass-energy can be radiated away?
Definition
20%
Term
Lobe radio galaxies can
Definition
all of these are correct
Term
To what use do astronomers put type-I supernova?
Definition
determining distances to other galaxies
Term
The lensing of a distant quasar is produced by ________ of a foreground galaxy.
Definition
all the normal matter and dark matter
Term
Which statement about Population II is incorrect?
Definition
these older stars are richer in heavier elements they have made in their cores
Term
The look-back time of an object is directly related to its:
Definition
distance
Term
Which statement about Population I is incorrect?
Definition
its stars surround the galaxy in the extended halo
Term
The huge lobe radio galaxy at the center of the Virgo Supercluster is
Definition
M-87, a giant elliptical galaxy
Term
A redshift of 2 implies a recession velocity of:
Definition
240,000 km/sec
Term
The type of galaxy where we can track its motion through the intergalactic medium is a
Definition
Head-Tail Radio Galaxy
Term
What is the Great Wall?
Definition
it is a large sheet of galaxies measuring 70 Mpc by 200 Mpc
Term
What would a redshift of Z = 3 imply about the velocity of the object?
Definition
velocity= 88% of the speed of light
Term
What two observations of an object allow for a determination of the Milky Way's mass?
Definition
objects velocity and distance from the galactic center
Term
Why are supermassive galaxies often found at the cores of rich galaxy clusters?
Definition
they are all the result of many galactic mergers; one galaxy growing at the expense of the others
Term
Not now considered a good explanation for the dark matter in the halo is
Definition
clouds of cool, neutral hydrogen
Term
A redshift of seven implies a galaxy is receding at .96c; use Ho = 70. km/s/Mpc to find its distance
Definition
13 billion light years
Term
Not only does the central engine of active galaxies and quasars require a black hole, ________ is also needed to
provide the energy radiated
Definition
an accretion disk of matter
Term
Which of these techniques has the most promise for detecting MACHOs?
Definition
observing duration and intensity of gravitational lenses
Term
Which two classes of objects were critical to the Shapley-Curtiss Debate of 1920?
Definition
globular clusters and spiral nebulae
Term
Which of these would be populated almost entirely by population II stars?
Definition
ellipticals
Term
Based on galactic rotation curves and cluster dynamics, we think dark matter
Definition
compromises about 90% of the entire mass of the universe
Term
The location of the center of the Galaxy was determined by Shapley from observations of:
Definition
RR Lyrae variables in globular clusters
Term
Active galaxies are having their central engines temporarily fed by what occurrence?
Definition
a close interaction with a neighboring galaxy
Term
Presently considered to be companions of the Milky Way are
Definition
the Large and Small Magellonic Clouds, and two nearby dwarf galaxy's in Sagittarius and Canis major
Term
Which of these is NOT considered a fine example of galactic collisions?
Definition
M-31 Andromeda
Term
In a lobe radio galaxy, the ultimate energy source for the entire galaxy is thought to reside:
Definition
in the galaxy's active nucleus
Term
The "aspect ratio" of thickness to width of the galactic disk is about:
Definition
1:100
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