March 18, 2003Lynn Cominsky - Cosmology A3501 Professor Lynn Cominsky Department of Physics and...
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March 18, 2003 Lynn Cominsky - Cosmology A350
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Professor Lynn Cominsky
Department of Physics and Astronomy
Offices: Darwin 329A and NASA EPO
(707) 664-2655
Best way to reach me: [email protected]
Astronomy 350Cosmology
March 18, 2003 Lynn Cominsky - Cosmology A350
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Group 7
Keith BuckleyEmily HaneyBrooke KrystosekAlex McMahon
March 18, 2003 Lynn Cominsky - Cosmology A350
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Shapes of Galaxies Spirals
disk shaped with spiral arms often have bright bulges in center contain interstellar gas, nebulae, star forming
regions, open clusters and globular clusters Barred Spirals
spiral arms emerge from end of bar gas from outer part of galaxy funneled to center
through the bar, forming new stars in bulge Lenticular (“lens-shaped”)
flattened disks of gas and dust no spiral arms
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Shapes of Galaxies Ellipticals
range from spherical to foot-ball shapes lots of old stars and globular clusters star formation is over or just restarting maybe the result of collision and merger of smaller
galaxies Irregulars
lots of gas and new stars forming rather small compared to spirals and ellipticals
Low surface Brightness lots of gas, but few stars can be rather large
March 18, 2003 Lynn Cominsky - Cosmology A350
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Galaxy Formation movie
Formation of galaxies in cold dark matter universe
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M31/Andromeda
Our nearest spiral neighbor
2 million light years away
Center of M31 has two optical nuclei
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M31/Chandra X-ray
Image of central part of our neighbor M31
Bright X-ray sources are binaries with black holes or neutron stars
Central BH is very cool, 30 million Mo
Center of M31
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Edge-on Spiral Galaxy
NGC 891 - we think our Galaxy looks like this
This is an infrared
composite image from
KPNO
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Starburst galaxies
Galaxies which are undergoing rapid phase of star formation
Supernova rate about 10 times higher Many bright stars Fluorescent gas clouds
NGC 4214HST
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Starburst Galaxy M82
Radio map is CO which traces H
IR map shows proto-stars
Radio
IR
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Starburst galaxy M82
X-ray evidence for intermediate mass black hole in M82
High supernova rate makes many smaller black holes, which may merge
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Hubble Galaxy Sequence
Ellipticals (round through oval) Spirals (centrally condensed with arms) Barred Spirals (distinct bar shape with bulge)
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Spiral Galaxies
Bulges formed over a short period very early in the young universe, perhaps through the collapse of a single cloud of hydrogen or merger of primeval star clusters.
NGC 1232/VLT
NGC 1288
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Spiral sequence
SandageHubble Space Telescope
NGC 5838/S0
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Spiral sequence
SandageHubble Space Telescope
NGC 5689/Sa
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Spiral sequence
SandageHubble Space Telescope
NGC 5965/Sb
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Spiral sequence
SandageHubble Space Telescope
NGC 7537/Sbc
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Barred Spiral M61
Bar across central region is made of stars, gas, and dust
Small bulge is dominated by a disk of material
Spiral arms begin at both ends of the bar
The bar is funneling material into the hub, which triggers star formation and feeds the bulge
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Barred Spiral NGC1365
Optical/Sandage
Optical/HST WFPC2
IR/HST NICMOS
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Irregular Galaxies
NGC 4753/I0
Sextans A
5000 light years across
5 million light years away
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Galaxy formation Large galaxy and satellite galaxy form 200 kpc portion of larger simulation at NCSA
Full simulation followed 262,144 gas particles and 262,144 dark matter particles (not shown) within a 16 Mpc comoving region. It took 140 hours on a Cray YMP.
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Galaxy Evolution
A computer simulation of a flat disk-type galaxy colliding with a dwarf galaxy. The dwarf galaxy cannot be seen, but its gravitational influences trigger the production of spiral arms in the gas-rich disk.
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Active Galaxies Quasars
Quasi-stellar radio source. (A radio source that is so far away that it looks like a star.)
Bright nucleus Highly variable Most produce strong X-rays Many have broad spectral lines (104 km/sec) Many QSOs (quasi-stellar objects, with no radio
emission) are often called quasars Seyfert galaxies
Spiral galaxies with bright nucleus Seyfert 2 galaxies are viewed through gas disk
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Active Galaxies Radio galaxies
quasars with radio emission (original quasars) some have two lobes, connected by jets some are wildly variable and have X-rays not especially bright in visible light often giant elliptical galaxies
BL Lac objects narrow lines highly polarized radio sources
Blazars wildly variable, have X-rays and gamma-rays quasars viewed down the jet axis
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Unified Model of AGN
All AGN are the same: central BH plus disk and jets
Differences in lines, jets, & spectra are due to different viewing angles
Also possible that BHs are being fed at different rates
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Seyfert Galaxy NGC 7742
Bright nucleus 3000 light years across 72 million light years away
HST
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Centaurus A/Optical
Giant elliptical galaxy
10 million light years away
Dark dust lane obscures the central region
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Centaurus A/Radio
Double Lobe Radio Galaxy
Image shows radio lobes superposed on optical image
Central black hole must be producing radio jets and lobes
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Centaurus A/X-ray
X-ray image from Chandra
Bright nucleus can be seen in center at location of black hole
Small jet to lower right ends in shocked region
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Centaurus A/IR IR map shows a
second galaxy (barred spiral) hiding inside Cen A’s dust lanes
Elliptical’s gravity helps barred spiral maintain its shape
Material funneled along the spiral's bar fuels the central black hole which powers the elliptical's radio lobesSymbiotic relationship
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M87 Optical
Giant elliptical galaxy At center of Virgo
cluster Many globular clusters
surround it Little dust and gas in the
galaxy 50 million light years
away
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M87 HST Movie
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M87 Optical Jet
HST IR and UV composite
Globular clusters also seen
Note shock waves and knot patterns in jet
Bright point at central black hole
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M87 Radio Jet
Central black hole is making jets
Jets are making bubbles of hot gas
Bubbles are as big as 200,000 light years
Smallest resolution VLBI image is 0.2 light years
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M87 X-ray and radio
X-ray contours on radio image
High energy emission from central black hole
ROSAT X-ray data
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X-ray Quiet AGN
Luminous optical nucleus yet X-ray quiet
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M87 - X-ray Quiet AGN?
Elliptical galaxies with known supermassive black holes from optical data
Advective accretion means that matter flows over the event horizon without making many X-rays due to the lack of a hot accretion disk
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Gamma-ray Quasars
3C 279 is a very bright, repeatedly flaring gamma-ray source, seen at MeV - TeV energies
3C273 is much
brighter at optical
energies
3C279
3C273
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Blazar movie
Shows rotating black hole in the center of Active Galaxy, which is emitting relativistic jets of material
Blazar is a quasar that is aiming its beams directly at us
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Most distant QSOs Redshift record is now around Z=6.5 Sloan Digital Sky Survey
Z = 5.0 Z = 4.75Z = 4.9
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Collisions and Mergers
Note: galaxies do not make noise when they collide!
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Galaxy Collision
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Galaxy Collisions, Part 2
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Cartwheel Galaxy
Wheel shape was formed from collision of two galaxies
Bright stars are forming at the edges of the wheel (105 light years in diameter)
Intruder galaxy is no longer visible
This is from HST
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Active Galaxies and Jets
What do Active Galaxies look like when viewed from different distances?
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Web Resources
Astronomy picture of the Day http://antwrp.gsfc.nasa.gov/apod/astropix.html
Imagine the Universe http://imagine.gsfc.nasa.gov
M87 radio images http://www.aoc.nrao.edu/~fowen/M87.html
Space Telescope Science Institute http://stsci.edu
Sloan Digital Sky Survey http://www.sdss.org/
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Web Resources
A. Ptak’s intermediate mass black hole in M82 http://astro.phys.cmu.edu/~ptak/m82/
T. di Matteo’s X-ray quiet AGN http://www-glast.sonoma.edu/HEADmeeting/tuesday/index.html
ROSAT X-ray images http://wave.xray.mpe.mpg.de/rosat/calendar/2000/oct
NCSA’s Unveiling the Hidden Universe http://www.ncsa.uiuc.edu/Cyberia/Bima/BimaHome.html#Unveiling
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Web Resources
NCSA M82 images http://www.ncsa.uiuc.edu/Cyberia/Bima/ExtraGal.html
Galaxy Formation Movie from NCSA http://www.ncsa.uiuc.edu/Cyberia/Cosmos/TheWorksMovies.html