File:Active Nucleus of NGC 4151 (40307201201).png

English: Note: Michell Revalski, an astronomer who studies these objects, has left comments on some of my images to add further details about what we're looking at! See here, or just scroll down.

This is an attempt to better highlight the glowing clouds of hydrogen being energized by some harsh light emitted by the central accreting black hole by using some of the narrowband data collected a while back with Hubble's WFPC2. If I understand correctly, the hydrogen gas is encircling the galaxy much as the rest of the stars and dust are doing, but is largely invisible at these wavelengths. When light from the black hole interacts with it, however, it then emits its own light, and becomes apparent.

A wider view of this galaxy is available here.

Data from the following proposals were used to create this image: A Cepheid-Based Distance to the Benchmark AGN NGC 4151 Imaging and Spectrophotometry of Seyfert Nuclei (FOS 14): Cycle 4 Observations

Luminosity: WFC3/UVIS F350LP Red: WFC3/UVIS F814W, WFPC2 F658N Green: Pseudo Blue: WFC3/UVIS F555W, WFPC2 F502N

North is NOT up. It is 30° counter-clockwise from up.