NEWS
Timing starburst: the role of galactic interactions in starting stars
New results from a study of the galaxy M82 using Hubble data suggest that globular clusters are still forming.
M
82 has gained fame as a
galaxy noted for the huge
numbers of stars forming there. But
why there? What triggered the condensation of interstellar gas and
dust to make young suns? For
M82, the answer seems to be its
neighbouring galaxy, M81.
“The last tidal encounter between
M82 and M81 about 600 million
years ago had a major impact on
what was probably an otherwise
normal, quiescent disk galaxy,”
says Richard de Grijs of the Institute of Astronomy, Cambridge, UK,
who is leading a team of European
and American astronomers in
studying M82. “It caused a concentrated burst of star formation in the
fossil starburst region. The active
starburst taking place today is
probably related to debris from
M82 itself that has slowly ‘rained’
back on the galaxy since the interaction with M81.”
Hubble Space Telescope observations of super star clusters that
formed when the two galaxies
interacted allowed the astronomers
to date the burst of star formation.
In addition, these detailed HST
observations are evidence that globular clusters, once thought to be
formed at least 10 billion years ago,
are still forming.
“We argue that these clusters are
in fact very young globular clusters,” says de Grijs. “Our results
support other observations, mostly
made with Hubble, that the formation of globular clusters does
indeed continue today. This is, in
our opinion, one of Hubble’s main
contributions to astrophysics to
date.”
The results are published in the
February 2001 issue of the Astronomical Journal.
The starburst region of M82 as seen by the WFPC on
the Hubble Space Telescope. The starburst region
from 600 million years ago is the bright area just
below and to the left of the central dust cloud, triggered by the violent encounter with M81 (NASA, ESA
and R de Grijs, Institute of Astronomy, Cambridge, UK).
Have you got a big idea?
Happy birthday to the ASP
Young inventors should start here, according to Claire Meal.
A
W
illiam Grant and Sons are
offering a new biennial cash
prize of £30 000, which will be
awarded to a European person or
European team, over the age of 18
and under 35, who have contributed to “the advancement of
mankind through invention or
discovery”.
A panel of judges at Paisley University will select three finalists,
who will present their ideas in
2.6
October at the Big Idea, the Inventor Centre in Irvine, Scotland.
Judges include Sir James Black and
Prof. Claude Detraz, the Scientific
Director of CERN at Geneva.
The award was devised by John
Moorhouse, Director of the Big
Idea in Irvine, and is intended to
encourage young inventors. The
closing date for entries is 30 April
and more details can be found at
www.bigidea.org.uk.
merica’s oldest astronomy society is 113 years old this year.
Now a general astronomy organization with some 6000 members, the
Astronomy Society of the Pacific
remains dedicated “to advance the
science of astronomy, and to diffuse
information concerning it”.
The ASP discharges its responsibilities by bringing together professional astronomers educators, amateur astronomers and the general
public, notably producing material
to support teachers.
The Society started out with 40
members, including Edward S
Holden who was the first director
of Lick Observatory and Charles
Burckhalter, a high-school science
teacher who became the director of
Chabot Observatory. They were
inspired to start the ASP by the
total solar eclipse that fell in California in 1889.
Now it is the largest such society
in the world and maintains its
headquarters in California. Many
happy returns.
April 2001 Vol 42