M77 is located at a distance of approximately 60 million
light years and is the prototype of a class of galaxies, known as
Seyfert Type 2. In active galaxies, typically the core shines
with the brightness of a billion solar luminosities, and the
brightness of the core fluctuates over the period of a few days
implying that the energy is being released from a region only a
few light-days in extent. The most likely source for this
enormous amount of energy is a "Massive Dark Objects" with a
total mass of 100 million stars like the Sun. Many scientists
believe that these Massive Dark Objects are "super massive''
In the case of M77, previous HST observations (left) have shown a number of hot gaseous clouds ionized or heated by the intense radiation from the nuclear source. A torus of "donut" of opaque dust and gas orbiting the massive central object confines escaping radiation to a diverging beam or "cone" of emission.
The new FOC/COSTAR observations (right) show with unprecedented clarity a much more extensive area of emission, produced by radiation from the active nucleus. An incredible wealth of new and previously unsuspected filamentary detail is also revealed in this near-nuclear gas, embedded within the diffuse emission. The knots and streamers of emission will enable the geometry of this fascinating nuclear region to be understood, and will offer new information on the nature of the clouds themselves.
A comparison between the ultraviolet light and the light emission of the clouds will provide insight into the hidden source of all the energy - probably a Massive Dark Object, and perhaps an obscured black-hole.
These data were taken by a team led by Duccio Macchetto of the European Space Agency (ESA) and Space Telescope Science Institute (STScI), and including William Sparks and Alessandro Capetti of STScI, using the Faint Object Camera and COSTAR "combination." These images were amoung the first taken with this new equipment in January 1994 (Early Release/ERO images).
Last Modification: June 20, 1999