Credit: X-ray: NASA/CXC/Univ. of Wisconsin-Madison/S.Heinz et al;
Optical: DSS; Radio: CSIRO/ATNF/ATCA
The youngest member of an important class of objects has been found using data from NASA's Chandra X-ray Observatory and the Australia Compact Telescope Array. A composite image shows the X-rays in blue and radio emission in purple, which have been overlaid on an optical field of view from the Digitized Sky Survey. This discovery, described in the press release, allows scientists to study a critical phase after a supernova and the birth of a neutron star.
Systems known as "X-ray binaries"
are some of the brightest X-ray sources in the sky. They consist of
either an ultra-dense star packed with neutrons --- a.k.a., a "neutron
star" --- or a black hole that is paired with a normal star like the Sun. As these two objects orbit one another, the neutron star or black hole pulls material from the companion star onto it.
A new study shows that the X-ray binary called Circinus X-1 is less
than 4,600 years old, making it the youngest ever seen. Astronomers have
detected hundreds of X-ray binaries throughout the Milky Way and other nearby galaxies. However, these older X-ray binaries only reveal information about what happens later in the evolution of these systems.
Researchers have found that the neutron star in Circinus X-1 is less
than 4,600 years old, making it much younger than any other X-ray binary
known in the Milky Way. Credit: Univ. of Wisconsin-Madison/S.Heinz et al.
Astronomers were able to determine the age of Circinus X-1 by
examining material around the orbiting pair. While the source itself
has been known for decades, the neutron star is usually so bright that
the glare from its X-ray light overwhelms any faint emission surrounding
it. The new Chandra data were obtained while the neutron star was in a
very faint state, which meant it was dim enough for astronomers to
detect the faint afterglow created by the supernova explosion plowing
through the surrounding interstellar gas. This, combined with
characteristics of the radio emission, allowed the researchers to
pinpoint the age of the supernova remnant. In turn, this information
reveals the age of the neutron star since they were formed at the same
time.
These results have been published
in the December 4th issue of The Astrophysical Journal. In addition to
those mentioned above, the other authors on this paper are Peter Jonker
of the SRON Netherlands Institute for Space Research, Niel Brandt of
Penn State University, Daniel Emilio Calvelo-Santos of the University of
Southampton, Tasso Tzioumis of the Australia Telescope National
Facility, Michael Nowak and Norbert Schultz of the Kavli Institute/MIT,
Rudy Wijnands and Michiel van der Klis of the University of Amsterdam.
Scale: Image is 10 arcmin across (about 76 light years)
Category: Neutron Stars/X-ray Binaries
Coordinates (J2000): RA 15h 20m 41.00s | Dec -51° 10' 00
Constellation: Circinus
Observation Date: 1 May 2009
Observation Time: 27 hours 25 min (1 day 3 hours 25 min)
Obs. ID: 10062
Instrument: ACIS
References: Heinz, S et al, 2013, ApJ accepted
Color Code: X-ray (Blue); Optical (Red, Green, Blue); Radio (Pink)
D
Distance Estimate: About 26,000 light years
