More Images of Cloverleaf Quasar (a.k.a. H1413+117)
1
Chandra X-ray Image of Cloverleaf Quasar
This is Chandra's X-ray view of the so-called Cloverleaf quasar, a
single object whose image has been reproduced four times through an
effect known as "gravitational lensing." This process occurs when the
gravitational field of a massive, intervening object bends and magnifies
light from a distant quasar to produce the multiple images. The
foreground galaxies in this case are too faint to be seen in these
images. One of the images in the Cloverleaf is brighter than the others
in both optical and X-ray light. This is due to "microlensing," where a
single or binary star in one of the intervening galaxies passes directly
in front of the small, X-ray producing region around the quasar's
supermassive black hole. X-ray microlensing gives astronomers a new and
extremely precise probe of the gas flow around the supermassive black
hole.
Scale: Image is 2 arcsec across
(Credit: NASA/CXC/Penn State/G.Chartas et al)
2
Hubble Optical Image of Cloverleaf Quasar
This optical image of the Cloverleaf quasar was taken with the Hubble Space
Telescope as part of the CfA-Arizona Space Telescope Lens Survey. The
position of the images in the X-ray sources align very well with Hubble
pictures. A comparison of the X-ray and optical images also shows that
image "A" is much brighter in X-rays (see image #1, above) than optical light. This is due to
an effect called gravitational microlensing, wherein a star or binary
star system in one of the intervening galaxies passes directly in front
of the small, X-ray producing region around the quasars supermassive
black hole. The optical light comes from a much larger region, so it is
not magnified by the passing star or stars.
Scale: Image is 5 arcsec per side
(Credit: NASA/STScI/D.Turnshek)
3
Illustration of Wind from Accretion Disk Around a Black Hole
This illustration depicts a massive black hole like the one at the
center of the Cloverleaf quasar. Around it is a swirling disk of gas,
which gradually pours down into the black hole. As the gas falls inward,
it heats up and glows brightly, getting hotter and hotter the closer it
is to the event horizon. Some of the gas is blown away from the disk
like steam from a kettle. As this gas streams off the disk, the intense
radiation generated by the very hot gas near the event horizon forces
the escaping gas into a cone and accelerates it to speeds as high as a
tenth the speed of light. The effect of X-ray microlensing, as detected
by the latest Chandra results, gives astronomers a new and extremely
precise probe of the gas flow around the supermassive black hole. The
area around the black hole that astronomers believed is magnified is
marked by the diamond region.
More Information on Quasars & Active Galaxies
(Credit: NASA/CXC/M.Weiss)
4
Illustration of Gravitational Lensing Effect
Single cosmic objects may appear as multiple images to astronomers through a
process known as gravitational lensing. This effect occurs when the
gravitational field of one or more foreground galaxies bends and
magnifies light from a much more distant object to produce multiple
images, as shown in the artist's rendering. In the case of the
Cloverleaf quasar, Chandra's X-ray view found four separate images
of this single object that is 11 billion light years away.
(Credit: NASA/CXC/M.Weiss)
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