Difference between revisions of "Radiative Processes in Astrophysics"

Revision as of 14:19, 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

(Sep. 7) thermodynamic equilibrium (RL 1.5)

Topics
Activities
- flipping pennies, rolling dice
- types of temperature
Problem Set 2 Assigned

(Sep. 12) semi-classical hydrogen

Topics:
- Classical Bohr Atom
Activities
- rederivation
- Rydberg
- dipoles/quadrupoles

(Sep. 14) Einstein coefficients

Topics:
- Einstein Coefficients
- Radiative Equilibrium
Activities
- estimating Einstein A for Ly-alpha
- effective photon absorption crosssection
Problem Set 3 Assigned

(Sep. 19) spectral line broadening

Topics
Activities
- what can you learn from a spectral line

(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 4 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

(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
Problem Set 5 assigned

(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

(Oct. 12) bound-free transitions

Topics
- Saha Equation
Activities
- stromgren spheres
- recombination coefficients
- work out in detail redshift of recombination
Problem Set 6 assigned

(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 7 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 8 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 9 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

(Nov. 16) radiative diffusion

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

@@ Line 26: / Line 26: @@
 == Topics by Date ==
-====(Th, Aug. 25) Radiative Quantities (RL 1.1-1.3; Mil 1.1-1.3)====
+====(Aug. 24) Radiative Quantities (RL 1.1-1.3; Mil 1.1-1.3)====
 * class mechanics
 ** syllabus
@@ Line 45: / Line 45: @@
 ** convert photon number density to specific intensity
-====(Tu, Aug. 30) radiative transport (RL 1.4; Mil 2.1-2.2)====
+====(Aug. 29) radiative transport (RL 1.4; Mil 2.1-2.2)====
 * Topics
 ** [[Radiative Transfer Equation]]
@@ Line 57: / Line 57: @@
 ** [https://github.com/AaronParsons/astro207/blob/master/bessel_V.dat bessel_V.dat]
-==== (Tu, Oct. 18) Maxwell's Equations and Plane Waves ====
+==== (Aug. 31) Maxwell's Equations and Plane Waves ====
 * Topics
 ** [[Maxwell Equations]] for Electromagnetic Waves
@@ Line 64: / Line 64: @@
 ** [[Larmor Formula]]
-====(Th, Sep. 1) scattering and absorption (RL 1.4; Mil 2.1-2.2)====
+====(Sep. 5) scattering and absorption (RL 1.4; Mil 2.1-2.2)====
 * Topics:
 ** [[Basic Scattering]]
@@ Line 74: / Line 74: @@
 ** high beams in fog
-==== (Tu, Sep. 6) thermodynamic equilibrium (RL 1.5)  ====
+==== (Sep. 7) thermodynamic equilibrium (RL 1.5)  ====
 * Topics
 ** [[Boltzmann distribution]]
@@ Line 84: / Line 84: @@
 * [https://github.com/AaronParsons/astro207/blob/master/ps_2016/ps02.pdf Problem Set 2] Assigned
-==== (Th, Sep. 8) semi-classical hydrogen ====
+==== (Sep. 12) semi-classical hydrogen ====
 * Topics:
 ** [[Classical Bohr Atom]]
@@ Line 92: / Line 92: @@
 ** dipoles/quadrupoles
-====  (Tu, Sep. 13) Einstein coefficients====
+====  (Sep. 14) Einstein coefficients====
 * Topics:
 ** [[Einstein Coefficients]]
@@ Line 101: / Line 101: @@
 * [https://github.com/AaronParsons/astro207/blob/master/ps_2016/ps03.pdf Problem Set 3] Assigned
-==== (Th, Sep. 22) spectral line broadening====
+==== (Sep. 19) spectral line broadening====
 * Topics
 ** [[Fourier Transform]]
@@ Line 109: / Line 109: @@
 ** what can you learn from a spectral line
-==== (Th, Sep. 15) radiation from accelerating charges (RL 3.3-3.4)====
+==== (Sep. 21) radiation from accelerating charges (RL 3.3-3.4)====
 * Topics
 ** [[Estimating Atomic Transition Strengths]]
@@ Line 117: / Line 117: @@
 ** Einstein A for CO
-====(Tu, Sep. 20)  molecular lines (RL 11) ====
+====(Sep. 26)  molecular lines (RL 11) ====
 * Topics
 ** [[Atomic and Molecular Quantum Numbers]]
@@ Line 125: / Line 125: @@
 * [https://github.com/AaronParsons/astro207/blob/master/ps_2016/ps04.pdf Problem Set 4] Assigned
+==== (Sep. 28)  masers ====
-==== (Th, Sep. 27)  masers ====
 * Topics
 ** [[Masers]]
@@ Line 133: / Line 132: @@
 ** laser pointers
-==== (Th, Sep. 29) collisional excitations ====
+==== (Oct. 3) collisional excitations ====
 * Topics:
 ** [[Collisional Excitations]]
@@ Line 141: / Line 140: @@
 ** collisional line-driven cooling
-==== (Tu, Oct. 4) free-free emission====
+==== (Oct. 5) free-free emission====
 * Topics
 ** [[Thermal Bremsstrahlung]] (RL 5.1-5.3)
@@ Line 151: / Line 150: @@
 * [https://github.com/AaronParsons/astro207/blob/master/ps_2016/ps05.pdf Problem Set 5] assigned
-==== (Th, Oct. 6) radiative equilibrium (RL 1.7-1.8; Mil 2.3-2.5)====
+==== (Oct. 10) radiative equilibrium (RL 1.7-1.8; Mil 2.3-2.5)====
 * Topics:
 ** [[Coulomb Focusing]]
@@ Line 158: / Line 157: @@
 ** timescale for photons/electrons to diffuse through a neutral IGM
-==== (Tu, Oct. 11) bound-free transitions ====
+==== (Oct. 12) bound-free transitions ====
 * Topics
 ** [[Saha Equation]]
@@ Line 167: / Line 166: @@
 * [https://github.com/AaronParsons/astro207/blob/master/ps_2016/ps06.pdf Problem Set 6] assigned
-==== (Th, Oct. 13) LTE and non-LTE ====
+====(Oct. 17) No Class====
+==== (Oct. 19) LTE and non-LTE ====
 * Topics
 ** [[Milne Relation]]
@@ Line 174: / Line 175: @@
 ** estimating recombination coefficients
-====  (Th, Oct. 20)  plasma effects====
+====  (Oct. 24)  plasma effects====
 * Topics
 ** [[Plasma Frequency]]
@@ Line 185: / Line 186: @@
 ** [https://github.com/AaronParsons/astro207/blob/master/pulsar.dat pulsar.dat]
-==== (Tu, Oct. 25) No Class ====
+==== (Oct. 26) compton scattering ====
-==== (Th, Oct. 27) compton scattering ====
 * Topics
 ** [[Lorentz transformations]]
@@ Line 196: / Line 195: @@
 ** relativistic intuition, velocity raptor
-==== (Tu, Nov. 1) Inverse Compton scattering====
+==== (Oct. 31) Inverse Compton scattering====
 * Topics:
 ** [[Inverse Compton Scattering]]
@@ Line 205: / Line 204: @@
 * [https://github.com/AaronParsons/astro207/blob/master/ps_2016/ps08.pdf Problem Set 8] assigned
-==== (Th, Nov. 3) Synchrotron Introduction ====
+==== (Nov. 2) Synchrotron Introduction ====
 * Topics:
 ** [[Introduction to Synchrotron Radiation and Relativistic Beaming]]
@@ Line 213: / Line 212: @@
 ** re-deriving synchrotron critical frequency
-==== (Tu, Nov. 8) Synchrotron Radiation ====
+==== (Nov. 7) Synchrotron Radiation ====
 * Topics
 ** [[Synchrotron Radiation]]
@@ Line 224: / Line 223: @@
 * [https://github.com/AaronParsons/astro207/blob/master/ps_2016/ps09.pdf Problem Set 9] assigned
-====  (Th, Nov. 10)  Synchrotron Self-Interactions ====
+====  (Nov. 9)  Synchrotron Self-Interactions ====
 * Topics
 ** [[Synchrotron Self-Interactions]]
@@ Line 232: / Line 231: @@
 **
-==== (Tu, Nov. 15) dust and grains====
+==== (Nov. 14) dust and grains====
 * Topics:
 ** [[Dust Absorption and Scattering]]
@@ Line 239: / Line 238: @@
 **
-==== (Th, Nov. 17) radiative diffusion ====
+==== (Nov. 16) radiative diffusion ====
 * Topics:
 ** [[Radiative Diffusion]]
@@ Line 247: / Line 246: @@
 **
-==== (Tu, Nov. 22) No Class ====
+==== (Nov. 21) No Class ====
-==== (Th, Nov. 24) No Class ====
+==== (Nov. 23) No Class ====
-==== (Tu, Nov. 29) Review 1 ====
+==== (Nov. 28) Review 1 ====
 * Review
-==== (Th, Dec. 1) Review 2 ====
+==== (Nov. 30) Review 2 ====
 * Review