Difference between revisions of "Radiative Processes in Astrophysics"

Revision as of 14:27, 23 August 2017

An introduction to the basic physics of astronomy and astrophysics at the graduate level. Principles of energy transfer by radiation. Elements of classical and quantum theory of photon emission; bremsstrahlung, synchrotron radiation. Compton scattering, plasma effects, atomic and molecular electromagnetic transitions. With applications to current research into astrophysical phenomena.

These are a collection of lectures covering topics in an introductory graduate astrophysics course on radiative processes. The subject matter is loosely drawn from Radiatve Processes in Astrophysics by Rybicki & Lightman.

At the end of the semester, each student will develop one new lecture on a subject of their choice to add to this website.

Class Code Repository

http://github.com/AaronParsons/astro207

Syllabus

Useful External References

Rybicki and Lightman, Radiative Processes in Astrophysics (course reference)
Mihalas and Mihalas, Foundations of Radiation Hydrodynamics
Osterbrock and Ferland, Astrophysics of Gaseous Nebulae and Active Galactic Nuclei
Shu, 'The Physics of Astrophysics, Volume I: Radiation
Longair, High Energy Astrophysics
Mihalas, Stellar Atmospheres
Rutten, Radiative Transfer in Stellar Atmospheres
Eddie Baron's GRK Lectures on Radiation Transport
Tony Readhead's Notes
Feynman's Lectures on Physics, Volume II

Topics by Date

(Aug. 24) Radiative Quantities (RL 1.1-1.3; Mil 1.1-1.3)

class mechanics
- syllabus
- references
  - Rybicki & Lightman
  - Astrobaki: learn better by teaching
- tools for figuring stuff out
  - theoretical derivation
  - order-of-magnitude estimation
  - physical intuition (hands-on modeling, analogies)
  - numerical simulation
- programming
  - Python Installation and Basic Programming
  - Revision Control (class repository)
Topics
- Specific Intensity
Activities
- convert photon number density to specific intensity

(Aug. 29) radiative transport (RL 1.4; Mil 2.1-2.2)

Topics
- Radiative Transfer Equation
- Optical Depth
Activities
- sliding pennies
- tree leaves
- locust swarm
Problem Set 1 assigned
- vega_spectrum.dat
- bessel_V.dat

(Aug. 31) Maxwell's Equations and Plane Waves

Topics
- Maxwell Equations for Electromagnetic Waves
- Electromagnetic Plane Waves
- Energy Density of Electromagnetic Waves
- Larmor Formula

(Sep. 5) scattering and absorption (RL 1.4; Mil 2.1-2.2)

Topics:
- Basic Scattering
- Central Limit Theorem
- Random Walks
- Black-Body Radiation (and Kirchoff's Law)
Activities
- photon diffusion
- high beams in fog
Problem Set 2 Assigned

(Sep. 7) thermodynamic equilibrium (RL 1.5)

Topics
Activities
- flipping pennies, rolling dice
- types of temperature

(Sep. 12) semi-classical hydrogen

Topics:
- Classical Bohr Atom
Activities
- rederivation
- Rydberg
- dipoles/quadrupoles
Problem Set 3 Assigned

(Sep. 14) Einstein coefficients

Topics:
- Einstein Coefficients
- Radiative Equilibrium
Activities
- estimating Einstein A for Ly-alpha
- effective photon absorption crosssection

(Sep. 19) spectral line broadening

Topics
Activities
- what can you learn from a spectral line
Problem Set 4 Assigned

(Sep. 21) radiation from accelerating charges (RL 3.3-3.4)

Topics
- Estimating Atomic Transition Strengths
- radiative dipole transitions
- photoexcitation cross-section
Activities
- Einstein A for CO

(Sep. 26) molecular lines (RL 11)

Topics
- Atomic and Molecular Quantum Numbers
- Rovibrational Transitions
Activities
- distortion in CO
Problem Set 5 assigned

(Sep. 28) masers

Topics
- Masers
Activities
- masers as transistors
- laser pointers

(Oct. 3) collisional excitations

Topics:
- Collisional Excitations
- Detailed Balance
Activities
- more CO molecular cloud
- collisional line-driven cooling
Problem Set 6 assigned

(Oct. 5) free-free emission

Topics
- Thermal Bremsstrahlung (RL 5.1-5.3)
- Opacity
- Kramer's Opacity
Activities
- free-free polarization
- simulating a free-free interaction

(Oct. 10) radiative equilibrium (RL 1.7-1.8; Mil 2.3-2.5)

Topics:
- Coulomb Focusing
- Thomson Scattering
Activities
- timescale for photons/electrons to diffuse through a neutral IGM
Problem Set 7 assigned

(Oct. 12) bound-free transitions

Topics
- Saha Equation
Activities
- stromgren spheres
- recombination coefficients
- work out in detail redshift of recombination

(Oct. 17) No Class

(Oct. 19) LTE and non-LTE

Topics
- Milne Relation
- A Review of Equilibria
Activities
- estimating recombination coefficients

(Oct. 24) plasma effects

Topics
- Plasma Frequency
- dispersion measure (RL 8.1)
- polarization
- Faraday rotation (RL 8.1-8.2)
Activities
- start de-dispersion coding
Problem Set 8 assigned
- pulsar.dat

(Oct. 26) compton scattering

Topics
- Lorentz transformations
- Doppler shift
- radiation from relativistic charges (RL 4.1, 4.2, 4.8; Grif 10.1)
- Compton Scattering
Activities
- relativistic intuition, velocity raptor

(Oct. 31) Inverse Compton scattering

Topics:
- Inverse Compton Scattering
- SZ Effect (RL 7.1-7.5)
Activities
- single scattering versus ensemble scattering
- compton saturation
Problem Set 9 assigned

(Nov. 2) Synchrotron Introduction

Topics:
- Introduction to Synchrotron Radiation and Relativistic Beaming
Activities
- re-deriving synchrotron critical frequency

(Nov. 7) Synchrotron Radiation

Topics
- Synchrotron Radiation
Activities
- re-deriving synchrotron spectrum
- phenomenological description of synchrotron decay
Problem Set 10 assigned

(Nov. 9) Synchrotron Self-Interactions

Topics
- Synchrotron Self-Interactions
Activities

(Nov. 14) dust and grains

Topics:
- Dust Absorption and Scattering
- dust formation/sublimation
Activities
Problem Set 11 assigned

(Nov. 16) radiative diffusion

Topics:
- Radiative Diffusion
- bolometric radiative equilibrium
- greenhouse effect
Activities

@@ Line 53: / Line 53: @@
 ** tree leaves
 ** locust swarm
-* [https://github.com/AaronParsons/astro207/blob/master/ps_2016/ps01.pdf Problem Set 1] assigned
+* [https://github.com/AaronParsons/astro207/blob/master/ps_2017/ps01.pdf Problem Set 1] assigned
 ** [https://github.com/AaronParsons/astro207/blob/master/vega_spectrum.dat vega_spectrum.dat]
 ** [https://github.com/AaronParsons/astro207/blob/master/bessel_V.dat bessel_V.dat]
@@ Line 73: / Line 73: @@
 ** photon diffusion
 ** high beams in fog
+* [https://github.com/AaronParsons/astro207/blob/master/ps_2017/ps02.pdf Problem Set 2] Assigned
 ==== (Sep. 7) thermodynamic equilibrium (RL 1.5)  ====
@@ Line 82: / Line 83: @@
 ** flipping pennies, rolling dice
 ** types of temperature
-* [https://github.com/AaronParsons/astro207/blob/master/ps_2016/ps02.pdf Problem Set 2] Assigned
 ==== (Sep. 12) semi-classical hydrogen ====
@@ Line 91: / Line 91: @@
 ** Rydberg
 ** dipoles/quadrupoles
+* [https://github.com/AaronParsons/astro207/blob/master/ps_2017/ps03.pdf Problem Set 3] Assigned
 ====  (Sep. 14) Einstein coefficients====
@@ Line 99: / Line 100: @@
 ** estimating Einstein A for Ly-alpha
 ** effective photon absorption crosssection
-* [https://github.com/AaronParsons/astro207/blob/master/ps_2016/ps03.pdf Problem Set 3] Assigned
 ==== (Sep. 19) spectral line broadening====
@@ Line 108: / Line 108: @@
 * Activities
 ** what can you learn from a spectral line
+* [https://github.com/AaronParsons/astro207/blob/master/ps_2017/ps04.pdf Problem Set 4] Assigned
 ==== (Sep. 21) radiation from accelerating charges (RL 3.3-3.4)====
@@ Line 123: / Line 124: @@
 * Activities
 ** distortion in CO
-* [https://github.com/AaronParsons/astro207/blob/master/ps_2016/ps04.pdf Problem Set 4] Assigned
+* [https://github.com/AaronParsons/astro207/blob/master/ps_2017/ps05.pdf Problem Set 5] assigned
 ==== (Sep. 28)  masers ====
@@ Line 139: / Line 140: @@
 ** more CO molecular cloud
 ** collisional line-driven cooling
+* [https://github.com/AaronParsons/astro207/blob/master/ps_2017/ps06.pdf Problem Set 6] assigned
 ==== (Oct. 5) free-free emission====
@@ Line 148: / Line 150: @@
 ** free-free polarization
 ** simulating a free-free interaction
-* [https://github.com/AaronParsons/astro207/blob/master/ps_2016/ps05.pdf Problem Set 5] assigned
 ==== (Oct. 10) radiative equilibrium (RL 1.7-1.8; Mil 2.3-2.5)====
@@ Line 156: / Line 157: @@
 * Activities
 ** timescale for photons/electrons to diffuse through a neutral IGM
+* [https://github.com/AaronParsons/astro207/blob/master/ps_2017/ps07.pdf Problem Set 7] assigned
 ==== (Oct. 12) bound-free transitions ====
@@ Line 164: / Line 166: @@
 ** recombination coefficients
 ** work out in detail redshift of recombination
-* [https://github.com/AaronParsons/astro207/blob/master/ps_2016/ps06.pdf Problem Set 6] assigned
 ====(Oct. 17) No Class====
@@ Line 183: / Line 184: @@
 * Activities
 ** start de-dispersion coding
-* [https://github.com/AaronParsons/astro207/blob/master/ps_2016/ps07.pdf Problem Set 7] assigned
+* [https://github.com/AaronParsons/astro207/blob/master/ps_2017/ps08.pdf Problem Set 8] assigned
 ** [https://github.com/AaronParsons/astro207/blob/master/pulsar.dat pulsar.dat]
@@ Line 202: / Line 203: @@
 ** single scattering versus ensemble scattering
 ** compton saturation
-* [https://github.com/AaronParsons/astro207/blob/master/ps_2016/ps08.pdf Problem Set 8] assigned
+* [https://github.com/AaronParsons/astro207/blob/master/ps_2017/ps09.pdf Problem Set 9] assigned
 ==== (Nov. 2) Synchrotron Introduction ====
@@ Line 221: / Line 222: @@
 ** re-deriving synchrotron spectrum
 ** phenomenological description of synchrotron decay
-* [https://github.com/AaronParsons/astro207/blob/master/ps_2016/ps09.pdf Problem Set 9] assigned
+* [https://github.com/AaronParsons/astro207/blob/master/ps_2017/ps10.pdf Problem Set 10] assigned
 ====  (Nov. 9)  Synchrotron Self-Interactions ====
@@ Line 237: / Line 238: @@
 * Activities
 **
+* [https://github.com/AaronParsons/astro207/blob/master/ps_2017/ps11.pdf Problem Set 11] assigned
 ==== (Nov. 16) radiative diffusion ====