Astronomy current events question: mass of dwarf galaxy RGG 118's central black hole

Astronomy 210L, fall semester 2015
Cuesta College, San Luis Obispo, CA

Students are assigned to read online articles on current astronomy events, and take a short current events quiz during the first 10 minutes of lab. (This motivates students to show up promptly to lab, as the time cut-off for the quiz is strictly enforced!)

Nicole Casal Moore, "Astronomers Find 'Teeny Supermassive Black Hole'" (August 11, 2015)
ns.umich.edu/new/releases/23057-astronomers-find-teeny-supermassive-black-hole

Researchers determined the mass of dwarf galaxy RGG 118's central black hole by measuring the:
(A) disappearance of nearby stars.
(B) distortion of background stars.
(C) pull on other galaxies.
(D) motion of gas around it.
(E) ripples in spacetime.

Correct answer: (D)

Student responses
Sections 70178, 70186
(A) : 7 students
(B) : 9 students
(C) : 6 students
(D) : 14 students
(E) : 1 student