M77 HST -

Hubble reveals the central region of the active galaxy M77

(NGC 1068)

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”

black-holes.

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.

Last Modification: 20 Jun 1999, 18:40 MET