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Galaxies: Structure, Dynamics, and Evolution Galaxies: Structure, Dynamics, and Evolution (From Website) Galaxies: Structure, Dynamics, and Evolution Galaxies: Structure, Dynamics, and Evolution (from website) “Galaxies are the basic building blocks of the universe, and we use them to trace the evolution of the universe. Fundamental processes such as star formation, recycling and enrichment of gas, formation of planets etc. all take place in galaxies. The course describes the structure of the galaxies, including dark matter, stars, and gas as well as the large scale structure in which galaxies are embedded. It discusses ongoing surveys of the nearby and distant universe. A special focus will be on the evolution of galaxies. The course builds on the bachelor lecture course “Galaxies and Cosmology” (Sterrenstelsels en Kosmologie), and assumes that the material in this course is known to the student. A very brief recapitulation will be given of the most important material.” 6 EC course Galaxies: Structure, Dynamics, and Evolution (from website) The approach we take in this course will be very empirical / observational. We find these interesting physical objects called galaxies nearby with observations. In this course, we will outline their properties and try to explain them using various physical ideas. This contrasts with the approach taken in the galaxy formation course originally taught by Joop Schaye -- where one tries to form galaxies ab initio just from theory. Lectures Rychard Bouwens Oort 459 [email protected] Lecture Hours: Huygens 414 Friday 11:15-13:00 Course Website: http://www.strw.leidenuniv.nl/~bouwens/galstrdyn/ Textbook? Useful Textbooks for the course will be “Galaxy Formation and Evolution” by Houjun Mo, Frank van den Bosch, and Simon White “Galaxy Dynamics” by James Binney & Scott Tremaine “Galactic Astronomy” by James Binney & Michael Merrifield The textbook includes a useful discussion of the material, but the course will not be organized to follow the presentation in the book. However, I will advise you as to where you can find the relevant material in the textbook. Layout of the Course Sep 9: Review: Galaxies and Cosmology Sep 16: No Class — Science Day Sep 23: Review: Disk Galaxies and Galaxy Formation Basics Sep 30: Disk Galaxies (II) Oct 7: Disk Galaxies (III) Oct 14: No Class Oct 21: Review: Elliptical Galaxies, Vlasov/Jeans Equations Oct 28: Elliptical Galaxies (I) Nov 4: Elliptical Galaxies (II) Nov 11: Dark Matter Halos Nov 18: Large Scale Structure Nov 25: Analysis of Galaxy Stellar Populations Dec 2: Lessons from Large Galaxy Samples at z<0.2 Dec 9: Evolution of Galaxies with Redshift Dec 16: Galaxy Evolution at z>1.5 / Review for Final Exam Jan 13: Final Exam How will you be evaluated? Final Exam (Written) -- 65% Homework -- 35% How many homework sets? You will have ~6 homework sets. Who am I? My name is Rychard Bouwens (studied in the United States: Berkeley & Santa Cruz) I study the most distant galaxies in the universe A good understanding of galaxies is very important for my research Discovery of Plausible Galaxy just ~400-450 Myr after Big Bang Candidate for the most distant galaxy ever discovered... Bouwens et al. 2011 (Nature, January 27, 2011) 11.09 414 Myr GN-z11 25.9 140 Oesch16 CANDELS 9.8 480 Myr Abell2744-JD 27.0 70 Zitrin14 Abell2744 11.09 414 Myr GN-z11 25.9 Oesch16 8.68 580 Myr EGS-zs8-1 25.2 Zitrin15 7.73 680 Myr EGS-zs7-1 25.0 Oesch15 Credit: Dan Coe How will this class be taught? 40% Powerpoint.... 60% Derivations on the blackboard... Teaching Assistants Daniel Lam Oort 570 [email protected] Gabriela Calistro Rivera Oort 551 [email protected] Both will also be available by appointment to answer your questions, and he also may hold office hours Who are you? Why don’t we go around the class and introduce ourselves briefly? Name Program -- Physics or Astronomy? Master’s Student? First or Second Year? Why interested in course? What’s your background? How many of you have taken Huub’s or Marijn’s course “Galaxies and Cosmology” when you were a bachelor student? How manyPass of you around are from thesheet physics program? How many of you have taken a Jarle’s course on galaxiesto collect or Koen’s info course on cosmology? Please ask questions This is *your* course. It is your opportunity to learn. By asking questions, you allow me to clarify issues It is assumed that you all are familiar with the following material from the Bachelor course here. 7-2-12see http://www.strw.leidenuniv.nl/˜ franx/college/galaxies12 12-c01-5 7-2-12see http://www.strw.leidenuniv.nl/˜ franx/college/galaxies12 12-c01-6 Background (assumed known) Clusters of galaxies, the universe Candidate dark matter particles Brief content of the course Galaxies and Cos- moly (Bachelors) 8) Galaxy formation Universe expansion 1) Introduction Growth of galaxies by gravity Galaxy scaling relations What is a galaxy ? Classifications 9) Galaxy formation - forming the stars Photometry, exponentials, r1/4 profiles, luminosity Gas cooling and star formation function formation of disks dynamical friction and mergers 2) Keeping a galaxy together: Gravity tidal tails in mergers Potentials for spherical systems 10) Observing galaxy formation 3) Galactic Dynamics High redshift galaxies from HST Equilibrium Fair samples of galaxies at high redshift collisions, Virial Theorem 4) Galactic Dynamics continued Timescales Orbits 5) Collisionless Boltzmann Equation equilibrium, phase mixing derivation of distribution function 6) Velocity Moments Jeans equations comparison to observations 7) Mass distribution and dark matter Evidence for dark matter from rotation curves Solar neighborhood, Oort limit Elliptical galaxies and hot gas But I know that many of you have not done your education here... so we will review the Bachelor material before moving onto the new material from this course... Key concepts from bachelor course 1. Galaxies omit radiation in just about every wavelength you can imag- ine di↵erent processes at di↵erent wavelengths, from (optical) stellar light of normal stars to relativistic electrons (radio, high energy) to hot accretion disks (UV, Xray) to bremsstrahlung from hot gas to ... 2. Galaxies are usually classified based on optical imaging. Hubble se- quence: ellipticals, S0s, spirals (barred and unbarred), Sa-Sd, irregulars, mergers. 3. The potential of a smooth density distribution can be calculated by an integral in 3 dimensions. The potential of a spherical system is simpler. Use the fact that the potential inside a spherical shell is constant (hence no force!). Outside of the shell, the potential is the same as that of a point-mass at the center of the shell with the same mass. Hence the force at a radius r is determined only by the mass inside r, as if the mass were at the center of the spherical distribution. 4. For a self-gravitating system, we can derive the virial theorem, 2K + W =0.Thisrelationcanbeusedtoestimatemasses,andscalingrelations. 5. Galaxy mass distributions can be derived from observed stellar ve- locities, gas rotation curves, hot X-ray gas, and many other methods These methods use the Jeans equations (moments of the Vlasov equation: see point 14), the relation between enclosed mass and circular velocity, and the equa- tions for hydrostatic equilibrium of gas (which are very similar to the Jeans equations. 6. The mass distributions of galaxies show strong evidence for dark mat- ter, i.e., the mass distribution continues much further out than the light. Typical examples are the rotation curves of galaxies, hot X-ray halos of el- lipticals, large masses of clusters. 7. Equilibrium: Galaxies are in (rough) equilibrium: the dynamical time is typically 108 years - much shorter than the age of the universe. 1 1. Galaxies omit radiation in just about every wavelength you can imag- ine di↵erent processes at di↵erent wavelengths, from (optical) stellar light of normal stars to relativistic electrons (radio, high energy) to hot accretion disks (UV, Xray) to bremsstrahlung from hot gas to ... 2. Galaxies are usually classified based on optical imaging. Hubble se- quence: ellipticals, S0s, spirals (barred and unbarred), Sa-Sd, irregulars, mergers. 3. The potential of a smooth density distribution can be calculated by an integral in 3 dimensions. The potential of a spherical system is simpler. Use the fact that the potential inside a spherical shell is constant (hence no force!). Outside of the shell, the potential is the same as that of a point-mass at the center of the shell with the same mass. Hence the force at a radius r is determined only by the mass inside r, as if the mass were at the center of the spherical distribution. 4. For a self-gravitating system, we can derive the virial theorem, 2K + W =0.Thisrelationcanbeusedtoestimatemasses,andscalingrelations. 5. Galaxy mass distributions can be derived from observed stellar ve- locities, gas rotation curves, hot X-ray gas, and many other methods These methods use the Jeans equations (moments of the Vlasov equation: see point 14), the relation between enclosed mass and circular velocity, and the equa- tions for hydrostatic equilibrium of gas (which are very similar to the Jeans Keyequations. concepts from bachelor course 6. The mass distributions of galaxies show strong evidence for dark mat- ter, i.e., the mass distribution continues much further out than the light. Typical examples are the rotation curves of galaxies, hot X-ray halos of el- lipticals, large masses of clusters. 7. Equilibrium: Galaxies are in (rough) equilibrium: the dynamical time is typically 108 years - much shorter than the age of the universe. 8. Stars dont collide calculate from typical density, velocity, and cross- section of stars. To understand equilibrium, one can ignore stellar collisions. The main challenge is to understand a system with > 1011 particles moving in their common gravitational potential.
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