Instrument: ROSAT PSPC

1
4U 1820-30
Instrument ROSAT PSPC Energy Range 0.5-1.6
keV Credit MPE 4U 1820-30 is an X-ray burst
source located in the globular cluster NGC 6624.
An X-ray burster is thought to be a neutron star
in a binary system which accretes fuel from the
main sequence companion before undergoing
impulsive thermonuclear burning. Neither
periodic nor random, these type 1 X-ray bursts
also reveal quasi-periodic oscillations through
power spectrum analyses of the burst emission.
This is thought to be a magnetospheric effect.
1 acrmin
2
AR Lac in X-rays
The active binary star system AR Lac is the
bright source near the center of this X-ray
image, produced by ROSAT over four days, covering
more than two orbits of the two stars. During
this period, a very strong flare was observed
from AR Lac, the peak X-ray luminosity of which
was 100,000 times the typical X-ray luminosity of
the Sun. Instrument ROSAT PSPC Energy
Range 0.5-1.6 keV Credit MPE
20 acrmin
3
AR Lac with ASCA
The active binary star system AR Lac is the
bright source off-center of this X-ray
image. Instrument ASCA GIS Energy Range
0.5-10 keV Credit NASA
4
Eta Carinae
Eta Carinae one of the most massive stars in
the Universe at over 100 solar masses, Eta
Carinae is highly unstable and prone to violent
outbursts. The last of these occurred in 1841,
when despite its distance, Eta Carinae briefly
became the second brightest star in the sky.
Distance 3 kpc Instrument HST WFPC2 Credit
STScI
5
Eta Carinae
The 100 Solar mass star Eta Carinae may be the
one star in the Milky Way massive enough to
become a hypernova. In these false-color X-ray
images, a bright source of X-rays at the center
of the shell is apparent in 1994 (right) but not
in 1992 (left). The bright source to the top of
each image is a massive star close to Eta
Carinae. Distance 3 kpc Instrument ROSAT
HRI Credit M.F. Corcoran, USRA
6
Eta Carinae in X-rays
The top two false-color images show the X-ray
emission from million-degree gas that surrounds
Eta Carinae in a large oval shell, taken six
months apart. The lower two images, also taken
six months apart, show X-rays from gas at
temperatures about 10-100 times hotter than the
gas in the shell.
Distance 3 kpc Instrument ROSAT PSPC Credit
M.F. Corcoran, USRA
7
White Dwarf HZ 43
30 acrmin
Stars like white dwarf HZ 43, pictured in this
X-ray mosaic (0.1-2.0 keV), have very soft X-ray
spectra and represent the end of one line of
stellar evolution. The observed X-rays most
likely come deep from HZ 43s gaseous
photosphere. The outer layers of the star
contain little or no elements other than hydrogen
or helium, hence they are essentially transparent
to the X-rays emitted by the much hotter inner
layers.
Instrument ROSAT PSPC Credit MPE
8
RE 1629780 (Meaty) in X-rays
The hot white dwarf RE 1629780, discovered
serendipitously during a pointing at the Abell
galaxy cluster, turned out to be one of the
brightest EUV sources in the sky. After the
British daily newspaper The Independent carried
the headline New telescope finds meaty UV
source, the name Meaty stuck among
astronomers.
Field 2 degree diameter Instrument ROSAT
WFC Credit University of Leicester
9
Nova Herculis 1991
15 acrmin
Nova Herculis 1991, shown here in X-rays, is a
nova consisting of a massive white dwarf in an
eclipsing binary system. Mass accreted onto the
white dwarf will eventually ignite runaway
thermonuclear reactions and blow off the outer
layers of the star.
Distance 5.4 to 8.3 kpc Instrument ROSAT
PSPC Credit MPE
10
PSR J0437-4715
The 5.75 ms pulsar PSR J0437-4715 (the lower,
second-brightest X-ray source at 0.1-2.4 keV ) is
the nearest and brightest millisecond pulsar
known. It is part of a binary system with an
orbital period of 5.5 days and a low-mass white
dwarf companion. The brighter source above the
pulsar is an active galaxy, RX J0437-4711.
15 acrmin
Distance 450 light-years Instrument ROSAT
PSPC Credit W.Becker, MPE
11
SLX 1744-299
The X-ray source SLX 1744-299 is located near the
Galactic center. Before ROSAT, the weak source
at the top was obscured by the brighter double
source. With ROSAT, this soft source forms the
"head" of the "Mouse," the corresponding radio
source named for its unusual form. SLX 1744-299
is likely a quickly-moving pulsar, which leaves a
"wake" of relativistic electrons to interact with
the magnetic field and generate the synchrotron
radio emission.
15 acrmin
Instrument ROSAT Credit MPE
12
Micro-Quasar GRS1915
In the above time-lapse sequence, micro-quasar
GRS1915 expels bubbles of hot gas in spectacular
jets -- away from a black hole. These
computer-enhanced radio images show one plasma
bubble coming almost directly toward us at 90
percent the speed of light, and another moving
away. Credit R. Spencer (U.
Manchester) et al. MERLIN
13
Sagittarius A
Sagittarius A, is thought to be a massive black
hole lying at the center of the Milky Way. This
radio image shows the source surrounded by
distant stars, vast dust clouds and swirling
rings of gas. The filaments surrounding
Sagittarius A are probably emissions from gas
being pulled into the black hole. Instrument
Very Large Array Credit S. Price, et al.
(Phillips Labs)
14
Pulsar EXO 2030375
Instrument ASCA SIS Credit Keith Sohl,
University of Leicester
15
Pleiades Star Cluster
The Pleiades star cluster in the Taurus
constellation contains cluster stars surrounded
by delicate blue wisps of dust-reflected
starlight. Seven of the brightest stars are
quite easy to see with the unaided eye and bear
the names of the Seven Sisters, the daughters of
Atlas.
Distance 425 light-years Instrument UK
Schmidt Telescope Credit Anglo-Australian
Observatory / Royal Observatory, Edinburgh.
16
Pleiades Star Cluster
The Pleiades, an open stellar cluster easily
visible to the naked eye in the northern
hemisphere, contains more than 500 stars and is
only about 70 million years old. This X-ray
image reveals that many of these very young stars
are X-ray sources at levels up to a thousand
times higher than that of the Sun.
Distance 425 light-years Instrument ROSAT
PSPC Credit MPE
17
Pleiades Star Cluster
The Pleiades star cluster, one of the jewels of
the northern sky in the Taurus constellation,
contains cluster stars -- easily visible with the
naked eye and in X-ray, as shown in this
composite of four deep ROSAT images.
Field 3x3 degrees Distance 425
light-years Instrument ROSAT Credit Thomas
Preibisch, Astronomisches Institut
18
Young Stellar Cluster IC 2391
Several bright optical sources are visible in the
central region of young stellar cluster IC348 in
the Perseus molecular cloud complex. Compare
this optical image with the ROSAT X-ray image of
the same region, which reveals a dense cluster of
X-ray sources.
19
Young Stellar Cluster IC 2391
A dense cluster of X-ray sources is visible in
the central region of young stellar cluster IC348
in the Perseus molecular cloud complex. More
that 100 X-ray sources in the cluster were
detected by ROSAT.
Field 1 degree Instrument ROSAT PSPC Credit
Dr. Thomas Preibisch, Astronomisches Institut
20
Young Stellar Cluster IC 2391
A true color image of the Young Stellar Cluster
IC 2391.
Field 1 degree Instrument ROSAT PSPC Credit
Dr. Thomas Preibisch, Astronomisches Institut
21
Young Stellar Cluster NGC 2516
This optical picture of a young stellar cluster
NGC 2516 reveals hundreds of distinct galaxies.
Compare this optical image with the ROSAT X-ray
image of the same region, which reveals dense
clusters of X-ray sources.
Field 40x40 arcmin Credit Dr. Thomas
Preibisch, Astronomisches Institut
22
Young Stellar Cluster NGC 2516
The young stellar cluster NGC 2516 reveals
hundreds of X-ray sources, produced from archived
data of a 21-hour ROSAT observation. Compare
this true color X-ray image with the an optical
image of the same region, which reveals distinct
galaxies.
Field 40x40 arcmin Instrument ROSAT
PSPC Credit Dr. Thomas Preibisch,
Astronomisches Institut
23
The Hyades Cluster
The 600 million-year-old Hyades cluster contains
stars that are quite young compared to the 4.5
billion-year-old Sun. This image shows more than
100 X-ray sources at 0.5-2.0 keV in the central
region of the open star cluster. The ROSAT
All-Sky Survey of Hyades has identified over 185
of the 400-plus cluster stars as X-ray emitters
at levels of 1-2 x 1028 erg/sec.
Distance 45 pc Instrument ROSAT PSPC Credit
MPE
24
The Hyades Cluster
Distance 45 pc Instrument Einstein
(HEAO-2) Credit NASA
The 600 million-year-old Hyades cluster contains
stars that are quite young compared to the 4.5
billion-year-old Sun. This image shows 108 X-ray
sources out of a total of 500 known members of
the cluster. The entire cluster is distributed
across more than 900 square degrees of the sky,
so this image only covers a small fraction of the
Hyades.