Please enter something

Astronomy Exam 3 Answers

question

Spiral Galaxies
answer

(denoted by S, and class a,b,or c) contain a flattend galactic disk, dense nucleous, wide variety of shapes.
question

Barred- Sprial galaxy
answer

Has presence of an elongated “bar” of stellar and interstellar matter.
question

elliptical galaxies
answer

no spiral arms and no obvious galactic disk, little internal structure.
question

Standard Candles
answer

easily recognizable candles, usuually aplies to very bright objects
question

Tully-Fisher relation
answer

used to obtain accurate estimate of a spiral galaxy’s luminosity by observing how fast it rotates
question

Galaxy Cluster
answer

a collection of galaxiesheld together by their mutal gravitation
question

Hubble’s Constant
answer

Recessional Velocity = H0 x distance Constant of proportionality between the velocities of remote galaxies and their distances. The slope of the line on the hubble diagram
question

Seyfert galaxies
answer

Class of astronomical objects whose properties lie between those of normal galaxies and those of the most energetic galaxies known.
question

Radio Galaxies
answer

active galaxies, emit large amounts of energy in the radio portion of the electromagnetic spectrum.
question

Quasars
answer

Are not stars but, enormously bright, distant galaxy with a giant black hole at its center.(have been observed in all partsof the electromagnetic spectrum)
question

Properties of Active Galatic Nuclei
answer

Hight luminosities, Mostly nonstellar, variable, Jets/other explosive activity, rapid internal motion, & interactions between galaxies.
question

Synchrotron radiation
answer

the radiation emitted by charged particles moving through a magnetic field; nonthermal radiation (no link between emission and the temperature of the radiated object.)
question

S0&SB0 Galaxies
answer

intermediate, in their properties between elliptical and spirals.
question

Irregular galaxies
answer

Do not fit into any of the other categories. Many are rich in gas and dust and are the sites of vigorous star formation.
question

Galactic Bulge
answer

Thick distribution of warm gas and the stars around the center of a galaxy.
question

Galactic disk
answer

flattend region of gas and dust, this is the region of active star formation.
question

Variable stars
answer

stars that alternately grow brighter and dimmer as their outer layers expand and contract in size(can be used to study halos)