Question

Which of the following is not a piece of evidence supporting the conclusion that active galactic nuclei are powered by accretion disks around massive black holes?

A) Observed radiation from the galactic center varies significantly in brightness in times as short as a few days.
B) Infrared observations show that many stars are forming near the centers of active galaxies.
C) Radio observations sometimes show long jets of material extending millions of light-years out from the galactic center.
D) The total amount of radiation coming from the galactic center is, in some cases, comparable to the amount of radiation put out by 10 billion or more ordinary stars.
E) Spectral lines from the galactic center indicate that clouds of gas are orbiting a central object at very high speed

Answer 1

Option (B) Infrared observations of star formation near active galactic centers do not support the accretion disk model around massive black holes. The other listed options (A, C, D, E) are consistent with the expected behavior of accretion disks around black holes in active galaxies.The correct answer is option B.

Step-by-step explanation:

The question asks which of the following options is not evidence supporting the conclusion that active galactic nuclei (AGNs) are powered by accretion disks around massive black holes. From the given options, the one that does not support the conclusion is (B) Infrared observations show that many stars are forming near the centers of active galaxies.

This statement discusses star formation, which is not directly related to the evidence of an accretion disk around a massive black hole.

• (A) Variability of observed radiation in short timescales indicates that the energy-emitting region must be very small, which is consistent with the area around a black hole.
• (C) Radio observations of long jets are aligned with the model, as these jets are believed to originate in the vicinity of the black hole and accretion disk, potentially due to magnetic fields powered by the accretion process.
• (D) The massive amount of radiation emitted can only be explained by a source that is extremely powerful, such as the gravitational energy released by material falling into a supermassive black hole.
• (E) High-speed orbiting gas clouds suggest the presence of a very massive central object, which in this context would likely be a supermassive black hole.

The evidence strongly points towards the core of AGNs containing supermassive black holes with rapidly rotating accretion disks emitting immense amounts of energy and fueling powerful jets perpendicular to the accretion disk's plane.The correct answer is option B.