Multiple Choice
How have astronomers measured the mass of the black hole at the center of our galaxy?
A) by using the rotation curve derived from 21-cm emission
B) by observing the motions of stars near the center of the galaxy
C) by measuring the brightness of the quasar
D) by measuring the Doppler shift of Sagittarius A*
E) by counting the number of supernova explosions near the black hole during the last century
Correct Answer:
Verified
Correct Answer:
Verified
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