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GEARS Workshop Galaxies Sarah Higdon

GEARS Workshop Galaxies Sarah Higdon. Galaxy Evolution. We will test some of the GEARS Galaxy Evolution Unit. There are two goals 1: For everyone to be comfortable with presenting the material in the classrooms.

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GEARS Workshop Galaxies Sarah Higdon

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  1. GEARS Workshop GalaxiesSarah Higdon

  2. Galaxy Evolution We will test some of the GEARS Galaxy Evolution Unit. There are two goals 1: For everyone to be comfortable with presenting the material in the classrooms. 2: For me to be able to revise/add to the material presented here using your expertise.

  3. Schedule: • 45 min WHAT DO GALAXIES LOOK LIKE – A bird’s-eye view • 45 minWHAT DO GALAXIES LOOK LIKE - More than the eye can see15mins CoffeeeeeeeeeeeeeeeeeeeBreak ~ 09:45 • 45 min MAJOR GALAXY COMPONENTS • 90 minGALAXY BUILDING BLOCKSLUNCH BREAK 1 hr ~ 12:15 • 45 minsCOLLIDING GALAXIES- CLOSE ENCOUNTERS AND TIDES • 45-90 minGAL CRASH applet15 min Coffee Break ~15:00 • 60 minCAPSTONE IDEAS/DEbriefing& Common Misconceptions Revisited/Suggestions On How to Improve this UniT. • NASA ONLINE Evaluations

  4. Units/Jargon: • Distance: 1 parsec = 3.26 light years = 3 x 1016m = 19 trillion miles (trillion = 1012) 1 Astronomical unit = 1.5 x108 km 93 million miles • We have sun centered view-point solopomorphic?Mass usually quoted in solar masses 1 solar mass = 2 x 1030 kg • Luminosity – again solar units Lsun = 4 x 1026 W

  5. Essential Questions • What are the major components of a galaxy? • What are the main types of galaxy? • How can a spiral galaxy form from a giant cloud? • How can an elliptical galaxy form from a giant cloud? • Where do you look for the oldest stars in our galaxy? • Where do you look for stellar nurseries? • What do galaxies looks like at different wavelengths ranging from radio to X-rays? • Is Hubble’s Tuning Fork Diagram Useful? • What are the basic building blocks for a galaxy and where is the material located in the galaxy? • How empty is the space between stars in a galaxy? • How big are galaxies? • How far apart are galaxies? • What types of telescope do I need in order to see the galaxy building blocks? • What happens when galaxies collide? • Why is the tidal force so important? • What types of systems can be formed from merging galaxies? • What are the basic model parameters needed in the GAlCrash applet in order to make a merger system of a given type. For example how can you make a supermassiveblackhole? A galaxy with a long tidal tail? A ring galaxy

  6. WHAT DO GALAXIES LOOK LIKE – A bird’s-eye view (45mins) 1a: Imagine you are an alien and you have one photo of the people in this classroom. In groups design a classification scheme based on your visual data ONLY. [5mins] each group has 1min to present their scheme. [5mins]

  7. Discussion of schemes [5mins] • What makes a scheme good, what makes it bad? • Can you use absolutes or only relative information eg heights of people or does that require distance? • Imagine comparing two images of a room full of people one taken from the ceiling one from the doorway – does you classification scheme still work? • Why do we use classification schemes? • Can you think of some everyday examples of classification schemes that you use? Clothes in wardrobes/drawers, kitchen cupboards, shopping list, etc.. • List some other scientific classification schemes –e.g. forms of energy, periodic table of elements, tree types, bird types, geometry

  8. 1b 15minsAgain in groups classify this set ofgalaxy images using your own scheme. Revise your scheme if necessary. • The galaxy images were taken with telescopes operating at optical wavelengths – if our eyes were good enough this is what we would see. (Why are our eyes poor observers of the Universe?) • The images are available as a handout (electronic copies also available).

  9. 1c: Optical Galaxy ClassificationThe Hubble Tuning Fork Diagram 100-inch reflecting telescope, Mt. Wilson Edwin Hubble Edwin P. Hubble

  10. Despite all the apparent variety of shapes, there are really only a few types of galaxies. Types of Galaxies

  11. “Face-on” v “Edge-on” Spiral galaxies are large: 30-40 kpc in diameter (90-120 thousand light-years). Globular clusters are centered on their cores. Face-on view: beautiful “pinwheel” appearance. Edge-on view: disk-like, and the disks are often very thin and full of dust.

  12. Spiral Galaxies Spiral - large (3-30 kpc), massive(109 - 1012 M), and rich in gas & dust. Large spiral galaxies may form 2-5 stars like the Sun each year. The Milky Wayis a spiral. Spirals: Sa smooth broad arms & large bulge, arms tightly wound Sc narrow well defined arms and small central bulge, arms loosely wound

  13. About 1/3 spiral galaxies have a elongated concentration of stars at their cores. These are called stellar “bars”, and these galaxies are called Barred Spirals. The Milky Way galaxy has a small bar, and so is a type SB galaxy. Often gas & dust travels down the bar to the inner-nucleus (to feed a Super Massive Black Hole?). This can be seen in the “dust lanes” visible along the stellar bars (lower left). Bars may arise from collisions with other galaxies. Bars may also arise spontaneously if the halo is not very massive. Barred Spiral Galaxies (SB)

  14. Barred Spiral Galaxies Spirals: SBa smooth broad arms, tightly wound &large bulge SBc narrow well defined arms, loosely wound and small central bulge

  15. These are large centrally concentrated balls of (typically) older stars. Elliptical Galaxies Unlike spiral galaxies, Elliptical galaxies (1) have very little atomic or cold molecular Gas, (2) have essentially no ongoing star formation, (3) tend to be reddish in color, and (4) show little or no rotation. Elliptical galaxies often have many more globular clusters than spirals. They can be much more massive than spiral galaxies. And while they may look “dull” in the optical, they can be spectacular sources of radio emission!

  16. Elliptical Galaxies E0 (spherical) => E7 (American football) NOTE THIS CAN BE ORIENTATION DEPENDANT think about how the football changes depending on how it is angled towards you

  17. Virgo Cluster 2000 Galaxies - here we see the Giant Elliptical Galaxy at the core(M86 is an S0 see next bit…)

  18. Leo I - Dwarf Elliptical Galaxy So few stars gas and dust you can see through its center

  19. S0 galaxies have properties intermediate between Spirals and Ellipticals: they have disks (no discernable arms) otherwise they look like ellipticals. Very little gas fluffy disks. S0 Galaxies S0 galaxies (like NGC 1201 at left) have very little gas - atomic or cold molecular - and so very little star formation. Roughly 1/3 of all S0 galaxies show some signs of a bar component (like NGC 2859 at left), just like spiral galaxies.

  20. Irregular Galaxies

  21. Hubble found that most galaxies could be organized by how large their bulges are, if they have bars, and how “wound up” their arms are.. The Hubble Tuning Fork Diagram The meaning of this diagram (or even if it has a meaning) is still being debated to this day!

  22. Hubble’s Tuning-Fork DiagramRe-classify the galaxies according to the Hubble Scheme How does it differ from your scheme?

  23. Galaxies to Classify: 1 - 3 1 3 2

  24. Galaxies to Classify: 4 - 6 4 6 5

  25. Galaxies to Classify: 7 - 9 8 9 7

  26. Galaxies to Classify: 10 - 11 11 10

  27. Galaxies to Classify: 12 - 13 12 13

  28. Galaxies to Classify: 14-17 14 15 16 17

  29. Galaxies to Classify: 18 - 19 18 19

  30. Galaxies to Classify: 20-23 20 21 22 23

  31. Galaxies to Classify: 24 - 25 24 25

  32. Galaxies to Classify: 26-29 26 29 28 27

  33. 30 31 Galaxies to Classify: 30 - 31

  34. 1d: There are plenty of websites that offer classification activities if you are already planning your capstone project you can select activities from the capstone sites: • Faulkes: this gives practice with their archive and you can make false color images. If you observe with Faulkes you could revisit this activity later in the semester and add your own observations): http://lcogt.net/en/education/activity/create-hubble-tuning-fork-diagramThe Sloan Digital Sky Survey:http://cas.sdss.org/runs/en/proj/advanced/galaxies/classification.asp • NASA/Hubble Galaxy Hunter a cosmic safari http://amazing-space.stsci.edu/resources/explorations/

  35. 2: 45 minWHAT DO GALAXIES LOOK LIKE - More than the eye can see • 2a 5minsLook at some images of people in the infrared from Spitzer. http://coolcosmos.ipac.caltech.edu/image_galleries/ir_portraits.html • Does your classification scheme for the people from part 1a still work? Make notes on your worksheet as to why/why not. • 2b 15minsSort some multi-wavelength images – try and group each object together. Fill out table • 2c 20 minsPick a galaxy set and view the images at each wavelength in DS9 using the mosaic view. Make notes on the differences. Look up some basic parameters about your galaxytry http://nedwww.ipac.caltech.edu • 2d 5 mins Discuss the limits of the Hubble classification scheme

  36. Coffee Break 15mins

  37. 3 MAJOR GALAXY COMPONENTS 45 mins • 3a 20mins We will review the major components and identify them in your galaxies and fill in a table – also discuss the major component that cannot be seen – dark matter halo, super-massive black holes. Briefly discuss ways of inferring the presence of hidden components – which is covered in more detail in another parrot of the galaxy unit.

  38. Milky Way Structure 2 x1011 stars 3 components: Disk: gas, dust, Young, Metal Rich Population I stars 0.6 kpc (2000 ly) thick 50kpc across (160,000ly) Bulge: Population I & II stars. 2kpc across (6500 ly) Halo: Old Metal Poor Population II stars - Globular clusters but mainly isolated stars

  39. 90% of matter in our galaxy is darkmatter only 10% is stars, gas & dust! What is Dark Matter ?

  40. Milky Way Components Any theory of galaxy formation should be able to account for all the properties below:

  41. 3c 83 Blue: optical Red: radio While elliptical galaxies often appear to be just a big ball o’ stars, many are shooting out extremely high energy electrons + magnetic fields millions of parsecs into space. Fornax A Ellipticals!! White: opticalOrange: radio

  42. 3c 353 Cygnus A A detailed look at the radio emission shows that it commonly consists of 3 components: (a) bright core, (b) two skinny “jets”, and (c ) expansive “lobes” at the ends of the jets. Radio Images: What kind of Galaxies?

  43. 3 MAJOR GALAXY COMPONENTS : • NASA In The Media • 3b 25minsFind a NASA press release discussing one of the major components • relay the story to the group - 2 mins allowed per presentation. • Prize for best presentation!

  44. 4 GALAXY BUILDING BLOCKS 90min:4a: How To make a Spiral/Lenticular galaxy0. SubgalacticUnits merge to make a protogalaxy.

  45. 4a: How To Make an Elliptical Galaxy0. SubgalacticUnits merge to make a protogalaxy.\

  46. 4 GALAXY BUILDING BLOCKS : • 4b 20 mins Make a list of what you think are the basic building blocks in each of the main galaxy components • Is it easy to see with a telescope when you are looking at our galaxy or when you are looking at another galaxy (far away)? • At what wavelength is it brightest? • Refer back to the multi-wavelength images for inspiration • Compare our lists – did we miss anything?

  47. GALAXY BUILDING BLOCKS 90min: • 4c 15 mins On a white board: Sort your components in relative sizes – guess a factor of 10 between each object from smallest largest. And masses again with a factor of 10

  48. GALAXY BUILDING BLOCKS 90min: 4d: 35 mins Exactly how empty is space? We will end up with a roadmap of how far apart stars are how big/how massive each component is e.g. gas in a given volume amount of dust etc.. Review the building blocks masses and sizes, Revise parts 4 b/c/ can you make some analogies keeping the correct scale factors. You have the solar system walk tonight is it possible to do a galaxy or cluster walk?

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