July 26, 2004

Part I: Galaxies and Galaxy Evolution

Part II: Clusters of Galaxies and Large Scale Structures

July 26, 2004

July 26, 2004

Exploring the Interstellar Medium Debrief

• What is the interstellar medium?• What do we know about its number

density?• What do we know the temperature of

the ISM?• What do we know about its heat?• What is the difference between heat

and temperature?• Did you prove this?

July 26, 2004

Exploring the Interstellar Medium Debrief

• What is the Local Bubble, and what are some possibilities for how it formed?

• What do we know now about the event and objects in our Universe?

• What else do we know?

Now lets move farther out…

• What is a galaxy?

July 26, 2004

Now lets move farther out…

• What do we know about galaxies?

• How do they evolve or form?

• Why do they form?

• How do we know?

• Prove it!

• What do our students need to know about galaxies?

July 26, 2004

Hidden Lives of Galaxies

• Read the first 2 pages of the handout

• Get into six groups of four

• Every group must have access to a wall with a poster

• Use the poster the answer the questions that are asked on the handout. (page 6)

July 26, 2004

M31/Andromeda

• Our nearest spiral neighbor

• 2 million light years away

Center of M31 has two optical nuclei

July 26, 2004

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

July 26, 2004

Edge-on Spiral Galaxy

• NGC 891 - we think our Galaxy looks like this

This is an infrared

composite image from

KPNO

July 26, 2004

Starburst galaxies

• Galaxies which are undergoing rapid phase of star formation

• Supernova rate about 10 times higher• Many bright stars• Fluorescent gas clouds• GRBs are in burst region.

NGC 4214HST

July 26, 2004

Starburst Galaxy M82• Radio map is CO

which traces H• IR map shows

proto-stars

Radio

IR

July 26, 2004

Starburst galaxy M82

• X-ray evidence for intermediate mass black hole in M82

• High supernova rate makes many smaller black holes, which may merge

July 26, 2004

Hidden Lives of Galaxies

In the same groups as before…

• Read page 7

• Read and follow the instructions on page 8

July 26, 2004

The Hubble Fork Diagram

July 26, 2004

July 26, 2004

Galaxy Formation movie

• Formation of galaxies in universe

July 26, 2004

Hidden Lives of Galaxies

Once again in your same groups…• Read page 9• Ok now based on all of the characteristics of

the different types of galaxies. Now it is your turn to match the unusual galaxies with the names on the right. (page 10) Make sure you give reasons why you choose the name.

• Continue reading pages 11-12, 13,and 22.

July 26, 2004

Break

• Which came first, the galaxy or its central black hole?

July 26, 2004

Active Galaxies• Now get into groups and lets talk about the

GLAST Active Galaxies Poster• Discussion topics:

– What is it explaining?– Why does science care?– How do these objects “fit in”?– What is the scientific evidence for these objects?– What are the of the different objects on this

poster?– Similar and dissimilar characteristics?

July 26, 2004

An Active Galaxy Journey

July 26, 2004

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

July 26, 2004

Galaxies and Black Holes

• Zooming in to see the central torus of an Active Galaxy.

Jet

Accretion disk

Black Hole

July 26, 2004

Radio Lobe Galaxy

Radio lobes (Q-tips)

Jet

Accretion Disk

July 26, 2004

Two Views of an Active Galaxy

View at an angle to jetView at 90 from Jet

Radio Lobe Galaxy Seyfert Galaxy

July 26, 2004

Seyfert Galaxy NGC 7742• Bright nucleus• 3000 light years across• 72 million light years away HST

July 26, 2004

Centaurus A/Optical

• Giant elliptical galaxy

• 10 million light years away

• Dark dust lane obscures the central region

July 26, 2004

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

July 26, 2004

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

July 26, 2004

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

July 26, 2004

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

July 26, 2004

M87 HST Movie

July 26, 2004

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

July 26, 2004

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

July 26, 2004

M87 X-ray and radio

• X-ray contours on radio image

• High energy emission from central black hole

• ROSAT X-ray data

July 26, 2004

Another view of an Active Galaxy

Looking down the Jet

From this view, we see the Active Galaxy emitting gamma rays and X-rays.

Blazar GalaxyQuasar 3C279

July 26, 2004

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

July 26, 2004

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

July 26, 2004

Most distant QSOs• Redshift record is now around Z=6.5• Sloan Digital Sky Survey

Z = 5.0 Z = 4.75Z = 4.9

July 26, 2004

Galaxy Collision

July 26, 2004

Galaxy Collisions, Part 2

July 26, 2004

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

July 26, 2004

How the Galaxy got its jets

July 26, 2004

Active Galaxies and Jets

• What do Active Galaxies look like when viewed from different distances?

July 26, 2004

Reflection and Debrief

• Now what do we know?

• What are the big ideas here?

• What do our students need to know?

• Is there anything else we need to know?

• Misconceptions

(take notes)

July 26, 2004

Reflection and Debrief

• What are some effective ways to teach students about galaxies and how they evolve?

• Standards???

(take notes)

July 26, 2004

Break

• Which came first the galaxy or the clusters?

July 26, 2004

Engage

• Examine the photograph of the Hubble Deep Field and the histogram of galaxies

• Fill out the worksheet

• Demo of the CLEA Wedge activity

• CLEA wedge plots

July 26, 2004

Wedge Plot Activity

• These data are from CLEA’s LSS lab

• Plot them on the wedge plot

• How many clusters do you see?

• Why is the wedge plot a better representation of the measurements than the linear plot?

July 26, 2004

“Stickman”

• “Slice” –style Redshift survey pioneered by Margaret Geller, Marc Davis and John Huchra

Distance is plotted vertically as given by redshifts

The body of the stickman is due to the Coma cluster

His arms form “walls”

July 26, 2004

Las Campanas Survey Done by Shectman et al. Largest redshift survey Clearly shows walls and voids 75-80% of space is devoid of bright galaxies Typical distance between 2 galaxies is around 7.5 Mpc Typical distance

between 2 clusters is around 20 Mpc

July 26, 2004

Clusters of Galaxies

• Clusters of galaxies are the largest gravitationally bound systems in the universe, with sizes of a few Mpc (a Mpc is about 3 million light-years).

• A typical cluster contains hundreds or thousands of galaxies

• Most of the mass is in the form of a hot intracluster gas, which is is heated to high temperatures (106-108K or several keV)

• Clusters are rare objects: fewer than 1 in 10 galaxies in the universe resides in clusters

July 26, 2004

Types of Galaxy Clusters• Regular clusters

– concentrated central core – well-defined spherical structure– often dominated by a giant galaxy – usually quite rich, M~1015 Mo

– most galaxies are elliptical or lenticular

• Irregular clusters– no well-defined center– ~half the galaxies are spirals– Often contain subclusters– Probably not steady state

July 26, 2004

Distances to Galaxy Clusters

• Going beyond Cepheid Variables to the next rungs on the Cosmic Distance Ladder

• Brightest Cluster Galaxies: The brightest galaxy in a cluster of galaxies has been used as a standard candle.

• But: rich clusters with many galaxies will probably have the most luminous galaxies even though these galaxies are very rare, while the brightest galaxy in less rich clusters are probably not as bright

July 26, 2004

X-ray emission from Clusters Gas in clusters of galaxies is held by mass where:

Mass of hot gas is more than 3 times the mass of the visible light galaxies in the Virgo cluster Strongest X-rays are around M87

Virgo/ROSAT

M = V2R

G

July 26, 2004

Cluster Formation

• Formation and evolution of a galaxy cluster (from T6 group at Los Alamos)

Evolution of a Cd galaxy cluster (from John Dubinski at CITA)

movies

July 26, 2004

Galaxy Harassment

• Spirals merge to form ellipticals• Biggest elliptical cannibalizes the others

to form one giant elliptical in the center of the cluster

• Dwarf ellipticals are formed by harassment (high velocity encounters) of low-mass spirals

• Detectable arcs of debris are left over – providing fuel for quasars

July 26, 2004

Virgo cluster of galaxies The Virgo cluster of galaxies is about 65 million light years away It contains about 2500 galaxies It is dominated by M87

M87

July 26, 2004

Virgo Cluster• It is the nearest rich cluster of galaxies • Classification - irregular • Covers about 100o of sky or at its distance it

spreads out over tens of millions of light years • Recessional velocity is about 0.3% of velocity of

light • X-ray emission concentrated around individual

galaxies, particularly M84 and M86• The strong radio galaxy M87 in the Virgo cluster

is also a strong source of X-rays

July 26, 2004

Perseus Cluster One of the closest galaxy clusters at a distance of 300 million light years Part of the Perseus Pisces supercluster which is 15 degrees across and has over 1000 galaxies

July 26, 2004

Hydra Cluster Distance of 840 million light years Several hundred galaxies in the cluster 35 million degree gas in center rising to 40 million in the outside Several million light years across the gas cloud

Optical/La Palma

July 26, 2004

Hydra Cluster

Radio/NRAO

X-ray/Chandra

July 26, 2004

Coma Cluster Coma cluster has about 1000 galaxies It is located near the north galactic pole It is about 250 million light years away (80 Mpc) Large bright central cluster is merging with smaller galaxy group at the lower right 3 Mpc

July 26, 2004

Small Cluster

X-rays from this smaller cluster were discovered by ROSAT Hot gas engulfs the two bright elliptical galaxies It is about 500 million light years away

July 26, 2004

Very Distant Cluster

This is a very red cluster, located at Z~1 It is the most distant cluster discovered by HST It may be too far away to have formed in a dense universe

July 26, 2004

Very Distant Cluster

This cluster is 8 billion light years away, so it formed when the universe was half its present age It is also very red It should not exist if the Universe is dense

July 26, 2004

How clusters affect galaxy evolution

• Ram pressure and turbulent stripping of gas from a spiral galaxy as it falls through the hot ICM of a rich galaxy cluster (by Vicent Quilis with Ben Moore)

• The galaxy model is 3d with a stellar disk, bulge + dark matter halo. The colours show the gas density in a thin slice centered on the disk

movie

July 26, 2004

Merging Clusters A2142 cluster The 50 million degree gas is coolest in the center where two clusters have finished merging The gas outside the center is 100 million degrees – heated by the collision Chandra image

July 26, 2004

Cannibal Cluster

A3827 is about 1.5 billion light years away The central dominant galaxy is eating five smaller galaxies

ESO/Optical

July 26, 2004

Large Scale Structure

• Distribution of matter in the Universe on scales at or above 10 Mpc

• Can be determined by– Galaxy surveys– Lyman-alpha forest studies– Quasar clustering studies

• Superclusters are largest structures seen – but they are not gravitationally bound

July 26, 2004

Local Supercluster

The Local supercluster contains the Virgo cluster of galaxies as well as about 50 galaxy groups

July 26, 2004

Superclusters

• Superclusters usually have 3-10 clusters of galaxies

• They are not gravitationally bound

• Our local supercluster contains the Virgo cluster (at 16 Mpc) and extends about 40- 50 Mpc

Local Supercluster

July 26, 2004

Walls and Voids

• Universe looks like soap bubbles in 3D• Galaxies occur on the bubble surfaces• Superclusters are formed where bubbles merge• Walls are made of elongated superclusters – the

largest is the “Great Wall” - about 100 Mpc in length at a distance of 100 Mpc

• Voids are about 100 Mpc in diameter – are 90% of space

• Clusters of galaxies are bright spots on the walls

July 26, 2004

Flyby universe movie

• Las Campanas data – notice the walls and voids as you fly by

July 26, 2004

Formation of Large Scale Structure

• Simulation by Martin White shows the evolution of structure starting with fluctuations in the Cosmic Microwave Background

movie

July 26, 2004

The End of Greatness

• Most recent surveys are so large that the largest structures (about 100 Mpc) are smaller than the survey size

• This is a 200 Mpc simulation from Ben Moore (using CDM)

July 26, 2004

Where are we going?

The Milky Way Galaxy is falling towards the Virgo cluster at ~300 km/s The Virgo cluster is falling towards the Hydra-Centaurus supercluster also at ~300 km/s

But the Hydra-Centaurus cluster is also falling towards something…..

July 26, 2004

Great Attractor

~1016 solar masses concentrated 65 Mpc away in the direction of Centaurus

Abell 3627 near the Great Attractor

The “Great Attractor” seems to be pulling in the Hydra-Centaurus super-cluster

But only 10% that amount of visible matter can be seen!

July 26, 2004

What do we know about our Universe?

• Using the chart found on page 23 of the handouts fill in the blanks to all the components of a galaxy.

• What do we know about the Universe now?

July 26, 2004

Reflection and Debrief

• Now what do we know?

• What are the big ideas here?

• What do our students need to know?

• Is there anything else we need to know?

• Misconceptions

(take notes)

July 26, 2004

Reflection and Debrief

• What are some of the effective ways to teaching these topics?

• Standards???

(take notes)

July 26, 2004

Web Resources (galaxies)

• 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

July 26, 2004

Web Resources (galaxies)

• 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/

July 26, 2004

Web Resources (galaxies)

• 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

July 26, 2004

Web Resources (LSS)

• On-line Journey through Astronomy http://csep10.phys.utk.edu/astr162/lect/gclusters/attractor.html

• J. C. Evans Astronomy 103 Course http://www.physics.gmu.edu/classinfo/astr103/CourseNotes/Html/Lec08/Lec08_pt1_universeClusters.htm

• Martin White’s Large Scale Structure http://astron.berkeley.edu/~mwhite/probes-lss.html

• XMM-Newton Large Scale Structure Survey http://vela.astro.ulg.ac.be/themes/spatial/xmm/LSS/First/FMos/index_e.html

July 26, 2004

Web Resources (LSS) Ned Wright’s ABCs of Distance http://www.astro.ucla.edu/~wright/distance.htm

Ray White’s Cluster of Galaxies Mug Shots http://www.astr.ua.edu/white/mug/cluster/clusters.html

Cambridge Cosmology Pages http://www.damtp.cam.ac.uk/user/gr/public/gal_lss.html

Greg Bothun’s Cosmology Book http://nedwww.ipac.caltech.edu/level5/Bothun2/Bothun_contents.html

J. Cohn’s Lyman alpha Forest pages http://astron.berkeley.edu/~jcohn/lya.html

July 26, 2004

Web Resources (LSS)

T-6 Group at LANL animations and picture http://qso.lanl.gov/pictures/Pictures.html

John Dubinski’s Big cluster simulations http://www.cita.utoronto.ca/~dubinski/bigcluster.html

2DF redshift survey project http://www.2dfquasar.org/

Ben Moore’s N-body simulations

http://star-www.dur.ac.uk/~moore/movies.html