Barred Spiral Galaxy NGC 5728: A Lighthouse Beacon From the Core of an Active Galaxy
[Right] - A NASA Hubble Space Telescope (HST) view of the core of the barred spiral Seyfert galaxy NGC 5728 reveals a spectacular bi-conical beam of light that is ionizing the gas in the central region of the galaxy.
This image is being presented at the American Astronomical Society meeting in Berkeley, California by Dr. Andrew Wilson of the Space Telescope Science institute (STScI), Baltimore, Maryland.
Because NGC 5728 is an active galaxy, the core might contain a super massive black hole surrounded by a disk of gas, according to astronomers. This hot disk glows with ultraviolet light. However, a dense ring of gas blocks Hubble's view of the black hole and glowing accretion disk. The visible and ultraviolet light escapes along the open ends of the gas "donut" several thousands of light- years from the nucleus. The ring thus shapes the escaping ultraviolet light into two lighthouse beacon style "ionization cones."
The image was made September 4, 1992 with the Wide Field and Planetary Camera (WFPC) in PC mode. Exposures were obtained in the light of doubly-ionized oxygen and neutral hydrogen.
[Left] - A ground based image of the bared spiral galaxy NUC 5728, located 125 million light-years away in the constellation Libra
Right Co-investigators: James A. Braatz (Univ. Of Maryland), Timothy M. Heckman (STScI), Julian H. Krolik (JHU), and George K. Miley (Leiden Observatory).
Left Courtesy of: Allan Sandage, Carnegie Observatories