June 5, 2002
Photo No: H2002-13c
Birth of Stars in Galactic Wreckage
Two powerful cameras aboard NASA's Hubble Space Telescope teamed up
to capture the final stages in the grand assembly of galaxies.
The photograph, taken by the Advanced Camera for Surveys (ACS) and
the revived Near Infrared Camera and Multi-Object Spectrometer (NICMOS),
shows a tumultuous collision between four galaxies located 1 billion
light-years from Earth. The galactic car wreck is creating a torrent
of new stars.
The tangled up galaxies, called IRAS 19297-0406, are crammed together
in the center of the picture. IRAS 19297-0406 is part of a class of
galaxies known as ultraluminous infrared galaxies (ULIRGs). ULIRGs
are considered the progenitors of massive elliptical galaxies.
ULIRGs glow fiercely in infrared light, appearing 100 times brighter
than our Milky Way Galaxy. The large amount of dust in these galaxies
produces the brilliant infrared glow. The dust is generated by a
firestorm of star birth triggered by the collisions.
IRAS 19297-0406 is producing about 200 new Sun-like stars every year
-- about 100 times more stars than our Milky Way creates. The hotbed
of this star formation is the central region [the yellow objects].
This area is swamped in the dust created by the flurry of star formation.
The bright blue material surrounding the central region corresponds to
the ultraviolet glow of new stars. The ultraviolet light is not obscured
by dust. Astronomers believe that this area is creating fewer new stars
and therefore not as much dust.
The colliding system [yellow and blue regions] has a diameter of about
30,000 light-years, or about half the size of the Milky Way. The tail
[faint blue material at left] extends out for another 20,000 light-years.
Astronomers used both cameras to witness the flocks of new stars that
are forming from the galactic wreckage. NICMOS penetrated the dusty
veil that masks the intense star birth in the central region. ACS
captured the visible starlight of the colliding system's blue outer
IRAS 19297-0406 may be similar to the so-called Hickson compact groups
-- clusters of at least four galaxies in a tight configuration that are
isolated from other galaxies. The galaxies are so close together that
they lose energy from the relentless pull of gravity. Eventually, they
fall into each other and form one massive galaxy.
This color-composite image was made by combining photographs taken in
near-infrared light with NICMOS and ultraviolet and visible light with
ACS. The pictures were taken with these filters: the H-band and J-band
on NICMOS; the V-band on the ACS wide-field camera; and the U-band on
the ACS high-resolution camera. The images were taken on May 13 and 14.
Credits: NASA, the NICMOS Group (STScI, ESA), and the NICMOS Science Team
(University of Arizona)