Illustration of an Intergalactic Gas
Cloud: A huge cloud of hot gas 800 million light years
from Earth.
Caption: This artistic rendering
illustrates how X-rays from a distant quasar dim as they pass
through a cloud of the intergalactic gas. Four independent teams
of scientists have detected intergalactic gas clouds with
temperatures in the range 300,000 to 5 million degrees Celsius
by observing quasars with Chandra. The spectrum of the quasar
PKS 2155-304 in the inset shows absorption due to oxygen in the
hot gas and allows astronomers to estimate the temperature,
density and mass of the absorbing cloud. The hot gas appears to
lie like a fog in channels carved by rivers of gravity and to
form part of a gigantic system of hot gas and dark matter that
defines the cosmic landscape. This system is thought to contain
more material than all the stars in the universe.
Chandra X-ray Observatory ACIS/LETG
Spectrum
CXC operated for
NASA by the Smithsonian Astrophysical
Observatory
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