Download Cold galaxies at low and high z

FROM SOUTHWOLD SKIES TO
THE UNIVERSE
- a journey through space astronomy
Michael Rowan-Robinson
Nov 27th 2008
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first detection of
electromagnetic radiation
outside the optical band:
Herschel (1800) detected
infrared radiation from the sun
Atmospheric transmission
Nov 27th 2008
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Radio astronomy
•1933 Karl Jansky, detected Milky Way at
radio wavelengths
•1940s Grote Reber, mapped the Milky Way
• 1945, John Hey, discovered point sources
• 1955-65 Cambridge, Parkes, surveyed the
sky and catalogued extragalactic radio
sources - radio-galaxies and quasars
• 1967 discovery of pulsars
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X-ray astronomy from space
•1948 T.R.Burnight detects X-rays from sun using V2
•1962 Giacconi detects X-ray binary Sco-X1 using Aerobee
rocket
•1963 Boyer detects Crab Nebula in X-rays (rocket)
•1965 first extragalactic X-ray source (M87, Byram, rocket)
•1970 Uhuru X-ray satellite maps sky at 2-20 KeV
many subsequent X-ray
missions, through to Chandra
and XMM, both launched in
1999
Nov 27th 2008
The Uhuru
satellite
before launch
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Uhuru detected X-rays
from compact sources
in binary systems (white
dwarfs, neutron stars,
black holes), from
quasars (massive black
holes) and from very hot
gas in clusters of
galaxies (100 million
degree)
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Nov 27th 2008
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Kitt Peak, Arizona, 1974, my first observing run
JCMT
1987
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first submillimetre
survey of the sky,
using JCMT.
several very
luminous galaxies
found - galaxies
in the midst of their
main star and heavy
element formation.
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IRAS
1983 saw the launch of
IRAS, the Infrared
Astronomical Satellite,
which made the first
all-sky survey at
infrared wavelengths,
from 10-100 microns
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The launch of IRAS
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IRAS - the infrared ‘cirrus’
emission from clouds
of interstellar dust in
our Galaxy
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south celestial pole
IRAS - star forming regions
LMC, the Large Magellanic Cloud
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constellation Orion
Uultraluminous
infrared galaxies
IRAS discovered
ultraluminous infrared
galaxies, forming stars
100-1000 times faster
than our Galaxy, probably
caused by mergers between
two galaxies
this is an image of Arp 220
Nov 27th 2008
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IRAS - dust debris disks
IRAS also discovered dust debris disks around stars, confirmed by
imaging with the Hubble Space Telescope, evidence for planetary
systems in formation. Today over 300 exoplanets are known.
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IRAS
the IRAS all-sky survey of infrared point-sources: white: star-forming
regions, blue: red giant stars, green: galaxies
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the William Herschel Telescope on La Palma,
used to follow up IRAS galaxies
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Mapping the Universe
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Large scale structure
The 3-dimensional
distribution of
galaxies shows
structure on
different scales.
This can be used
to estimate the
average density
of the universe.
In dimenionless
units:
Wo ~ 0.27
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How much matter is there in the
universe ?
The light elements D, He, Li
are generated from nuclear
reactions about 1 minute
after the Big Bang. The
abundances turn out to
depend sensitively on the
density of ordinary matter
in the universe.
density ~ 4.10-28 kg/cu m
Wb ~ 0.04
Nov 27th 2008
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Evidence for Dark Matter
the speed at which stars
orbit round a galaxy points
to the existence of a halo
of dark matter.
sensitive surveys show
that this can not be due to
stars, or gas.
Nov 27th 2008
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Evidence for Dark Matter 2
images of clusters
of galaxies with
HST show arcs
due to gravitational
lensing. These can
be used to weigh
the cluster. Again,
the cluster is
dominated by dark
matter.
Nov 27th 2008
Abell 2218
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Need for Dark Matter
So there is far more matter (Wo ~ 0.27 ) out
there than can be accounted for by the stuff we
are made of (Wb ~ 0.04).
85% of the matter in the universe is ‘dark’
matter (the neutralino ?)
Particle Physicists hope to detect this at the
Large Hadron Collider
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Audit of the mass-energy
of the Universe:
4% ordinary matter
23% dark matter
73% dark energyDark en
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History of the universe
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Nov 27th 2008
SPITZER, 2003
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IC1396, the Elephant’s Trunk
- a dark globule inside
an emission nebula
- a pair of newly
formed stars have
created a cavity
- the animation shows
how the appearance
changes from the
optical, where dust
absorbs light to the
infrared where the dust
radiates
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QuickTime™ and a
MPEG-4 Video decompressor
are needed to see this picture.
Nov 27th 2008
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infrared emission from debris along a comet orbit
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Sombrero galaxy
- end-point of a galaxy merger
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Two interacting galaxies
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Visible and infrared images of the star-forming
galaxy Messier 82
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two new European Space Agency
missions due for launch in April 2009
Planck
Herschel
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Keck and VLT
(Very Large
Telescopes)
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how to detect z = 10 galaxies ?
James Webb Space Telescope
Nov 27th 2008
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