Sarah Keegan
Headquarters, Washington, D.C.                                                  
November 8, 1993
(Phone:  202/358-1547)

Mike Finneran
Goddard Space Flight Center, Greenbelt, Md.
(Phone:  301/286-5565)

Ray Villard
Space Telescope Science Institute, Baltimore, Md.
(Phone:  410/338-4514)


RELEASE:  93-203

HUBBLE DEEP-SKY SURVEY FINDS INTERACTING GALAXIES IN A CLUSTER


     In one of the deepest celestial surveys yet made by NASA's 
Hubble Space Telescope (HST), astronomers have discovered a small 
group of previously unknown interacting galaxies estimated to be 3 
billion light-years away. 

     Because Hubble caught the galaxies in an early stage of 
evolution, they offer new clues to developing a much clearer 
understanding of how galaxies have changed over time.

     Nearly half of the galaxies appear to be merging with one 
another in the Hubble image.  This suggests a very rapid evolution 
of galaxies and clusters of galaxies over very short time spans, 
according to astronomers.  These results might help improve 
theories which predict that galaxies evolved faster than earlier 
thought, perhaps due to the influence of dark matter -- invisible 
or undetected mass pervading the universe. 

     A galaxy is a city of stars held together by their mutual 
gravitation.   Galaxies are considered the basic building blocks 
of the universe.  HST's high resolution image reveals that many 
early galaxy "building blocks" are in pairs.

     "In many of the pairs, at least one galaxy is blue, which 
indicates that star
formation is underway at a high rate, possibly triggered by 
interaction with the neighbor galaxy," says Dr. Richard Griffiths, 
The Johns Hopkins University, Baltimore.  "Such mergers and 
interactions may be the rule within galaxy clusters rather than 
the exception."

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     "Though the largest galaxy in the image is about the size of 
our own Milky Way galaxy, most  of the galaxies detected are much 
smaller than our own.  They might eventually merge to form the 
many large galaxies that we see in the universe at the present 
day," he says.

     Over the past 2 years, Griffiths and colleagues at The Johns 
Hopkins University, with a team of astronomers in the United 
States and Britain, have used the Hubble Space Telescope to carry 
out a serendipitous survey of small areas of sky.  This is done 
with the HST Wide Field Camera, which is used to take a picture of 
a piece of sky close to a main target, such as a quasar or galaxy, 
that is being observed by a different Hubble instrument. 

     The survey is one of several key projects using Hubble.  In 
previous images, the deep survey has uncovered remote and unusual 
galaxies never before resolved by an optical telescope.  HST's new 
level of detail reveals a bizarre variety of shapes and structures 
in these distant galaxies, which previously only appeared as fuzzy 
blobs from ground-based telescopes.

     The Hubble Space Telescope is a program of international 
cooperation between NASA and the European Space Agency.

     The distance to the largest galaxy in the image has been 
measured by Prof. Rogier Windhorst and his group at Arizona State 
University, using the Multi-Mirror Telescope in Arizona, operated 
by the University of Arizona and the Smithsonian Institution.

                             - end -

NOTE TO EDITORS:  Color and black and white images to illustrate 
this release are available to media representatives from NASA's 
Broadcast and Imaging Branch, 202/358-1900.  Photo numbers are:  
     Color:  93-HC-433 and 93-HC-434
     B&W:  93-H-481 and 93-H-482