The Analysis of Quasar Absorption Line Spectra

Chris Churchill
Assistant Professor of Astronomy

A TEXT BOOK ON RESEARCH INTO THE INTERGALACTIC AND INTERSTELLAR GASEOUS BARYONIC COMPONENTS OF THE UNIVERSE FOR GRADUATE STUDENTS AND ADVANCED UNDERGRADS

The book is scheduled to be delivered to Cambridge University Press in the January - April of 2008 (I had an accident and broke my hand- delaying the book even further - again) and will be part of its Cambridge Astrophysic Series.

All material Copywrite (C) Christopher W. Churchill (2008).

Preliminary Message to the Reader

Due the lack of an up-to-date reference book on the research methods employing the methods of quasar absorption lines, I have undertaken the task of writing one. The notes are derived from my lectures and research experience, and are targeted toward researchers of astronomy and astrophsyics. The book includes
  • The physics of radiative transfer, atomic systems (sorry, no molecules), and gas structures with focus on application for spectral analysis.
  • Physically motivated distribution functions. Analysis methods such as chi-square least squares fitting and maximum likelihood analysis. The observable features in quasar spectra, the ionization breaks, GP trough, Lyman leaks, absorption line curve of growth.
  • Fundamentals of spectroscopic theory, spectrograph design, characteristic of spectra, reduction of spectra, and spectroscopic analysis of absorption and emission features
  • introduce the cosmological setting and experimental methods of quasar absorption lines, with emphasis on analysis to extract quantities based upon the physics of radiative transfer, atomic absorption properties, and cosmological evolution.
    • Since the last iteration, the book has changed significantly, so I have taken the chapters off line.

    If you are interested in obtaining any of the material, please contact me via email. Let me know which chapter or sections you would like. I provide an outline below.

    I am interested in proof readers! If you wish to contribute, please email me. I will of course give all contributers their very due acknowledgments.

    Contents

    Subsections are not listed...

    Chaper 1: Introduction

    1.1 Quasars and Astronomy
    1.2 Qualitative History of the Gaseous Universe
    1.3 The Tool of Quasar Absorption Lines
    1.4 Taxonomy of Absorbers
    (10% complete)

    Chaper 2: The Cosmography

    2.1 The Metric
    2.2 Relativistic Dynamics
    2.3 Parameterized Cosmology
    2.4 H_0 and the Three Omega's
    2.5 Scale Factor and Redshift
    2.6 Dynamics and Redshift
    2.7 Time and Redshift
    2.8 Distance and Redshift
    2.9 Velocity and Redshift
    2.10 Volume and Redshift
    2.11 Probability of Line of Sight Intersection
    2.12 Luminosity and Surface Brightness
    (100% complete)

    Chaper 3: Data and Parameter Estimation

    3.1 Statistical Descriptors of Data
    3.2 Common Distribution Functions
    3.3 Confidence Intervals and Levels
    3.4 Statistical Tests
    3.5 The Sensitivity Function
    3.6 Parameterized Distribution Functions
    3.7 Maximum Likelihood Method
    3.8 Chi-Square Minimization
    (100% complete)

    Chaper 4: Chemical Elements and Atomic Structure

    4.1 Abundances
    4.2 Hydrogen and Hydrogen-Like Ions
    4.3 Wave Model of the Atom
    4.4 Grotrian Diagrams

    Appendix: Ionization Potentials
    (50% complete; additional sections may be added)

    Chaper 5: Radiative Transfer

    5.1 Defining the Radiation Field
    5.2 Terms of Radiative Transfer
    5.3 The Transfer Equation
    5.4 Applying the Transfer Equation

    (98% complete; additional material may be added)

    Chaper 6: Gas Physics and Ionzation Processes

    6.1 Velocity and Speed Distributions
    6.2 Mean Kinetic Energy of Particles
    6.3 Gas Pressure
    6.4 Gas Dynamics
    6.5 Thermodynamic Equilibrium
    6.6 The Ultraviolet Background Radiation
    6.7 Photoionization Balancing
    6.8 Collisional Ionization Balancing
    6.9 Heating and Cooling
    (20% complete; currently working on this one)

    Chaper 7: Cross Sections

    7.1 Absorption, Scattering, and Emission
    7.2 The Monochromatic Plane Wave
    7.3 Defining Cross Sections
    7.4 The Classical Oscillator
    7.5 Atomic Bound-Bound Absorption
    7.6 Atomic Continuum Asbsorption
    7.7 Scattering Cross Sections
    7.8 The Total Exctinction Coefficient
    7.9 Recombination
    7.10 The Total Emission Coefficient
    (90% complete; currently finishing this one)

    Chaper 8: Absorption Spectral Features

    8.1 Thermal Broadening
    8.2 The Voigt Profile
    8.3 Equivalent Widths: The Curve of Growth
    8.4 Rest-frame Equivalent Widths
    8.5 Ionization Edges: The Lyman Break
    8.6 Absorption Line Systems
    (90% complete)

    Chaper 9: Spectrographs

    9.1 The Spectrograph
    9.2 Diffraction Gratings
    9.3 Low Order Spectrographs
    9.4 Echelle Spectrographs
    9.5 Monochromatic Resolving Power
    9.6 Spectral Purity
    9.7 Instrumental Spread Function (ISF)
    9.8 ISF Convolution
    9.9 Pixelization
    (100% complete)

    Chaper 10: Spectroscopic Data

    10.1 Low versus High Resolution
    10.2 Charged Couple Devices
    10.3 Reducing the Data Suite
    10.4 Extracting the Spectrum
    10.5 Wavelength Zero Point
    10.6 Flux Calibration
    10.7 Continuum Fitting
    10.8 Combining Spectra
    10.9 Signal-to-Noise Ratio (SN)
    10.10 Exposure Times and SN
    10.11 Magnitudes
    10.12 The K-Correction
    (100% complete)

    Chaper 11: Analysis of Quasar Spectra

    11.1 Objective Feature Finding
    11.2 Equivalent Width Limits
    11.3 Gaussian Profile Fitting
    11.4 Identifying Absorption Systems
    (95% complete)

    Chaper 12: Analysis of High Resolution Spectra

    12.1 Velocity Resolution
    12.2 Complexity of Absorption Systems
    12.3 Analysis of Associated Transitions
    12.4 Velocity Moments
    12.5 Apparent Optical Depth (AOD) Spectra
    12.6 AOD Analysis
    12.7 Voigt Profile Decomposition
    12.8 Pixel Statistics Analysis
    (80% complete)

    Chaper 13: Statistical Analysis of Absorbers

    13.1 Surveys
    13.2 Redshift Path Sensitivity Function
    13.3 Redshift Number Density
    13.4 Sizes of Absorbers
    13.5 Equivalent Width Distribution
    13.6 Two-Point Velocity Clustering
    13.7 Mean Gas Density
    (100% complete)

    Chaper 14: Modeling Absorbers

    14.1 Photoionization Modeling
    14.2 Collisional Ionization Modeling
    (50% complete)

    Chaper 15: The Universe of Absorbers

    15.1 The Gunn-Peterson Trough
    15.2 Lyman Leaks and Reionization
    15.3 The Proximity Effect
    15.4 The Lyman Alpha Forest
    15.5 The He II Forest
    15.6 The Lyman Limits Systems (LLS)
    15.7 Galaxy Halos
    15.8 The Damped Lyman Alpha Systems (DLAs)
    (20% complete)