Normal Galaxies

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Normal Galaxies
Normal Galaxies
General cities on Earth fuzzy
blobs background light of the
Universe Classification Hubble
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Spirals S
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Orientation Matters
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Barred Spirals SB
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Elliptical E
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Irregulars I
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Hubble Tuning Fork
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Spiral (easy)
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Elliptical
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Barred Spiral
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Spiral (med)
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Irregular
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Spiral2 Ellipticals
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Spiral (edge)
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S0?
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Spirals (Leo Trio)
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Spirals (interacting)
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Spirals
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Galaxy Types
SPIRALS MW, Andromeda S or SB bulge size, bar
or not A to G stars white flat
disk gasdust spiral arms central bulge extended
halo density waves
ELLIPTICALS And. companions E ellipticity GKM
stars red football no gas/dust random
orbits old stars all halo large size range
IRREGULARS LMC, SMC I mess O to A
stars blue catchall lots gas/dust star
formation also globulars no halo? recent
collisions

• examples
• letters
• defined
• stars
• details
• big deal

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Local Group Galaxies
Populations 3 big spirals Milky Way, And,
M33 most are dwarf ellipticals estimated at 40
billion NOT evolution along tuning fork
One Megaparsec
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Galaxy Redshifts
velocity Ho X distance (km/sec)
(Mpc) Velocity redshift
Ho H naught value 70 km/sec/Mpc supernova
e out to 1 Gigaparsec (one billion parsecs)
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Galaxy Formation
Bottom Up not as well understood as star
formation galx harder to observe galx not
observed forming galx more complex galx
suffer collisions that change them Evidence Hubbl
e Deep Field
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Hubble Deep Field
3D View 100 hours magnitude 30 (!) redshifts
to 100 Mpc away
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Building Blocks
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Galaxy Formation
Bottom Up not as well understood as star
formation galx harder to observe galx not
observed forming galx more complex galx
suffer collisions that change them Evidence Hubbl
e Deep Field 10 Byr blue irregulars more
spirals long ago few spirals near cluster
centers starburst galaxies are
observed stomachs of giant ellipticals eaten
galaxies
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Elliptical Bellies
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Galaxy Formation
Bottom Up not as well understood as star
formation galx harder to observe galx not
observed forming galx more complex galx
suffer collisions that change them Evidence Hubbl
e Deep Field 10 Byr blue irregulars more
spirals long ago few spirals near cluster
centers starburst galaxies are
observed stomachs of giant ellipticals eaten
galaxies tidal streams in MW Process small
blobs of proto-galaxies combine early Universe
small density fluctuations
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Galactic Train Wreck
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Active Galaxies
Active Galaxies
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Active Galaxies
General 1-10 of all galaxies jets depends
on distance age Emission brighter than normal
galaxies non-thermal emission synchrotron
radiation radio, infrared, x-rays broad
spectral lines high velocity gas in core
central engine
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M87 picture
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Active Galaxy Types
SEYFERTS middle aged spiral visible, IR,
radio 10 X MW 0.1 /yr yes small nuclei Fe
lines
RADIO GALX 20something elliptical radio 10 X
MW 0.1 /yr yes jets Local Group size symmetric
QUASARS teenager both? IR 1,000-100,000 X
MW 10-1000 /yr extreme point source high
redshift

• age
• types
• wavelengths
• energy
• variable?
• details

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Quasar Host Galaxies
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Central Engine
Characteristics high luminosity non-stellar
emission highly variable jets high gas
velocities broad emission lines Answer black
holes million to billion Msun!!! Process tear
apart star heats bloats disk ionizes
atoms magnetic fields locked in rotating
accretions disk particles whipped to high
speeds synchrotron radiation
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AGN Evolution
Quasars ? Seyfert/Radio ? Normal Process black
holes eat out cavities gradually reduce
violence jets disappear variabilty
drops brightness drops
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Evolution Map
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Supermassive Black Holes
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AGN
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Typical Quasar
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