Bullets and Wine Glasses: The Exciting Encounters of Galaxy Clusters
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This document provides an overview of galaxy clusters and the evidence for the Big Bang theory. It discusses how galaxy clusters formed in the early universe, and how observations of galaxy clusters provide evidence for the existence of dark matter. Specifically, it describes how measurements of galaxy cluster collisions, like the Bullet Cluster, show that dark matter is separated from the hot gas, providing strong evidence that dark matter exists and interacts only through gravity.
Bullets and Wine Glasses: The Exciting Encounters of Galaxy Clusters
- 1. Bullets and Wine Glasses: The Exciting Encounters of Galaxy Clusters John ZuHone NASA/Goddard Space Flight Center
- 2. The Big Bang ? Universe out ＾of nothing￣ ? ~13.8 billion years ago
- 3. General Relativity ? Albert Einstein, 1916 ? Matter and energy cause ＾dents￣ and ＾warps￣ in the space and time of the universe, which causes gravity ? Einstein found that when he applied his equations to the entire universe, it implied the universe had a beginning (which he didn¨t like)
- 4. The Expanding Universe ? Expansion of the universe ? In the late 1920¨s Edwin Hubble measured the distances to galaxies ? The further away a galaxy was, the faster it was moving away ? This implies universal expansion
- 5. Redshift
- 6. Einstein Was Convinced Einstein Hubble Walter Adams Saurabh W. Jha (Rutgers) v = H0d
- 7. Cosmic Background Radiation ? Another key evidence: ? If there was a Big Bang, it should have been very hot and very dense in the beginning ? This means that the radiation from that hot period should still be here ? Today, this radiation is in the form of microwaves ? Discovered by Penzias and Wilson in 1965
- 8. Cosmic Background Radiation Seeds of structure formation Planck Satellite, 2013
- 9. The Formation of Structure Andrey Kravtsov (U. Chicago)
- 10. Galaxy Clusters ? Fascinating objects! ? Big: ~10 14 M｝, ~10 6 ly ? Galaxies: star formation, supernovae, active galactic nuclei ? Intracluster medium: ? diffuse (<1 atom per cubic centimeter), ? hot (hundreds of millions of degrees), magnetized plasma ? Dark Matter: makes up the majority of the mass, only interacting by gravity
- 11. Chandra (NASA) XMM-Newton (ESA) ASTRO-H (JAXA) Athena (ESA)
- 12. Galaxies in Visible Light Abell 1689 Virgo Cluster
- 13. X-Rays Reveal Cluster Gas Perseus Abell 520 ＾El Gordo￣ http://chandra.harvard.edu
- 14. ＾But what about that ｀dark matter¨ stuff? You said you can¨t even see it! How do you know it¨s there?￣
- 15. Dark Matter Fritz Zwicky Abell 2744 Virial Theorem: kinetic energy potential energy cluster mass cluster radius Newton¨s gravitational constant average galaxy speed 10x more matter than we can see!!
- 16. Gravitational Lensing Again, implies 10x more mass than we can see
- 17. Tools of the Trade: High- Performance Computing Hardware Software
- 18. Massive Computing Hardware ? Thousands, tens of thousands, hundreds of thousands of processors ? NASA, NSF, DOE, etc´ ? On a somewhat smaller scale, private companies are providing similar access to consumers (Amazon, Google, Microsoft, etc.) Blue Gene/P at Argonne National Laboratory in Chicago
- 19. Sophisticated Physics Software ? Computer simulations of gas and particle physics ? Hundreds of millions of cells, billions of particles ? Calculations spread out across the processors in a (mostly) balanced fashion
- 20. A Key Trick: Adaptive Mesh Re?nement
- 21. The Formation of a Cluster
- 22. The Bullet Cluster Dark Matter Hot Gas Galaxies Maxim Markevitch (NASA) and Doug Clowe (Ohio U.)
- 23. Shock Fronts/Waves ? A wave in a gas that is faster than the speed of sound in that gas ? Behind the shock wave, the gas is denser, and hotter
- 26. How Much Energy? ? Kinetic energy of a bullet shot from a 9 mm pistol: ? about 500 Joules ? or burning a 100-Watt light bulb for about 5 seconds ? Kinetic energy of the gas ＾bullet￣ in the Bullet Cluster: ? about 4 〜 1063 Joules ? or about 1061 9 mm bullets ? or about 1050 atomic bombs
- 27. Dark Matter
- 28. Hot Gas
- 29. The ＾Smoking Gun￣ for Dark Matter
- 30. Sloshing
- 31. Sloshing
- 33. Sloshing
- 35. Sloshing Sloshing stirs up the cluster gas, accelerating high-energy electrons which spiral around the magnetic ?eld and radiate in radio waves Simona Giacintucci (U. Maryland)
- 36. Important! ? Why do these analogies work as well as they do? ? Because the laws of physics are the same everywhere in the universe. ? The scales and the materials may be different, but the basic physics is the same!
- 37. My Own Trajectory ? Undergraduate: University of Illinois at Urbana-Champaign ? Physics major ? Research at U. Illinois, U. Chicago ? Graduate: University of Chicago ? Astronomy and Astrophysics Program ? Computational Science Graduate Fellowship ? Postdoctoral Research ? Harvard University ? NASA This took: persistence, support from friends and family, connections, and a little bit of luck.
- 38. Thinking About a Career? ? Some bits of advice´ ? Learn to program: C, C++, Fortran, Python, etc. ? Do undergraduate research. You can apply at many places! ? Find something that interests you. Read about it. Ask people about it. (Find reputable scientists on social media and ask them questions!)
- 39. Thinking About a Career? ? Some bits of advice´ ? Don¨t give up. It will be hard. It will take lots of time. But, if you love it, it¨s worth it. ? Have a life outside of science. Have friends that aren¨t scientists. ? Be open to career paths outside the norm of academia: software/hardware support, science journalism, science consultant for businesses, etc´
- 40. Website: http://www.jzuhone.com Twitter: @astrojaz Google Plus: +JohnZuhone