The nearby dwarf galaxy NGC 1569 is a hotbed of vigorous star birth
activity which blows huge bubbles that riddle the main body of the
galaxy. The galaxy’s “star factories” are also manufacturing brilliant
blue star clusters. This galaxy had a sudden and relatively recent onset
of star birth about 25 million years ago, which subsided about the time
the very earliest human ancestors appeared on Earth.

In this new image, taken with NASA’s Hubble Space Telescope, the bubble
structure is sculpted by the galactic super-winds and outflows caused by
a colossal input of energy from collective supernova explosions that are
linked with a massive episode of star birth.

One of the still unresolved mysteries in astronomy is how and when
galaxies formed and how they evolved. Most of today’s galaxies seem to
have been already fully formed very early on in the history of the
universe (now corresponding to a large distance away from us), their
formation involving one or more galaxy collisions and/or episodes of
strongly enhanced star formation activity (so-called starbursts).

While any galaxies that are actually forming are too far away for
detailed studies of their stellar populations even with Hubble, their
local counterparts, nearby starburst and colliding galaxies, are far
easier targets.

NGC 1569 is a particularly suitable example, being one of the closest
starburst galaxies. It harbors two very prominent young, massive
clusters plus a large number of smaller star clusters. The two young
massive clusters match the globular star clusters we find in our own
Milky Way galaxy, while the smaller ones are comparable with the less
massive open clusters around us.

NGC 1569 was recently investigated in great detail by a group of
European astronomers who published their results in the January 1, 2004
issue of the British journal, Monthly Notices of the Royal Astronomical
Society. The group used several of Hubble’s high-resolution instruments,
with deep observations spanning a wide wavelength range, to determine
the parameters of the clusters more precisely than is currently possible
from the ground.

The team found that the majority of clusters in NGC 1569 seem to have
been produced in an energetic starburst that started around 25 million
years ago and lasted for about 20 million years. First author Peter
Anders from the Gottingen University Galaxy Evolution Group, Germany
says, “We are looking straight into the very creation processes of the
stars and star clusters in this galaxy. The clusters themselves present
us with a fossil record of NGC 1569’s intense star formation history.”

The bubble-like structures seen in this image are made of hydrogen gas
that glows when hit by the fierce winds and radiation from hot young
stars and is racked by supernovae shocks. The first supernovae blew up
when the most massive stars reached the end of their lifetimes roughly
20-25 million years ago. The environment in NGC 1569 is still turbulent
and the supernovae may not only deliver the gaseous raw material needed
for the formation of further stars and star clusters, but also actually
trigger their birth in the tortured swirls of gas.

The color image is composed of 4 different exposures with Hubble’s Wide
Field and Planetary Camera 2 through the following filters: a wide
ultraviolet filter (shown in blue), a green filter (shown in green), a
wide red filter (shown in red), and a Hydrogen alpha filter (also shown
in red).

Image credit: ESA, NASA & P. Anders (Gottingen University Galaxy
Evolution Group, Germany)

NOTE TO EDITORS: The team is composed of Peter Anders (Gottingen
University Galaxy Evolution Group, Germany), Richard de Grijs
(University of Sheffield, UK), and Uta Fritze-v. Alvensleben
(Gottingen University Galaxy Evolution Group, Germany).

This composite image was constructed with data from the ESO/ST-ECF
Science Archive. The original Hubble exposures were obtained by Hunter
(Proposal 6423).

Electronic images and additional information are available at: and

Animations of the discovery and general Hubble Space Telescope
background footage are available from:

For more information, please contact:
Peter Anders, Gottingen University Galaxy Evolution Group, Germany
(Phone: +49-(0)551-39-5054; Email: or

Lars Lindberg Christensen, Hubble European Space Agency Information
Centre, Garching, Germany, (Phone: +49-(0)89-3200-6306; Cellular (24
hr): +49-(0)173-3872-621; E-mail: or

Ray Villard, Space Telescope Science Institute, Baltimore, MD,
(Phone: 410-338-4514; E-mail:

The Space Telescope Science Institute (STScI) is operated by the
Association of Universities for Research in Astronomy, Inc. (AURA),
for NASA, under contract with the Goddard Space Flight Center,
Greenbelt, MD. The Hubble Space Telescope is a project of
international cooperation between NASA and the European Space
Agency (ESA).