Chris Churchill's Home Page

CHRISTOPHER W CHURCHILL
PROFESSOR
DEPARTMENT OF ASTRONOMY
NEW MEXICO STATE UNIVERSITY

You can now preorder the individual volumes published by Cambridge University Press (will ship in December 2025).

ASTRONOMY TEXTBOOK

Quasar Absorption Lines
Volume 1: Introduction, Discoveries, and Methods
Volume 2: Astrophysics, Analysis, and Modeling

This advanced textbook is suitable for advanced undergraduate students, graduate students, and seasoned researchers in the field. Together, the two volumes provide a comprehensive and detailed treatment of the topic of quasar absorption lines, including its historical development, scientific findings, theoretical foundations, and methods of analysis.

Volume 1: Introduction Discoveries, and Methods ($120)
This volume chronicles six decades of quasar spectroscopy. The book details the nature of the Lyα forest, Lyman limit systems, damped Lyα absorbers, deuterium (D/H), 21-cm absorbers, HI and HeII reionization, the WHIM, and the multiple ionization phases of metal line absorbers. Galaxies and their connections to these absorbers are treated in depth, as are the taxonomy and classes of AGN/quasar spectra and their associated absorption lines. (695 pages,227 figures; 2575 references)
PREORDER: ISBN-10: 0521867606 ; ISBN-13: 978-0521867603
Link: @ Cambridge University Press
Link: @ Amazon

Volume 2: Astrophysics, Analysis, and Modeling ($100)
This volume treats the theory and analysis of absorption lines, including the physics of atomic transitions, gas and ionization physics, the cosmological model, radiative transfer, spectrograph design, analysis of spectra, and multi-component, multiphase chemical-ionization modeling. Pragmatic approaches to conducting and assessing absorber counts in large absorption line surveys is presented. Throughout, objective analysis methods are emphasized and presented for clarity of practical application. (621 pages, 188 figures; 518 references)
PREORDER: ISBN-10: 1009715216 ; ISBN-13: 978-10099715218
Link: @ Cambridge University Press
Link: @ Amazon

I study the evolution of galaxies by examining their circumgalactic medium (CGM), a gaseous reservoir of dynamically complex, multi-phase, metal enriched gas that surrounds galaxies. The gas is observed in absorption using the technique of quasar absorption lines. When a quasar resides behind a galaxy, the GCM gas imprints absorption patterns in the spectrum of the quasar. From these we measure the gas temperature, metallicity, kinematics, etc. We aim to learn about the role of the cycle of gas (called the baryon cycle) in governing the formation and evolution of galaxies.

(left) A QSO quasar spectrum with emission lines annotated and (across the top) with spectral regions annotated for the various ions that can be observed in absorption. (right) A combined optical and radio image of the galaxy M81. The radio emission (orange) shows how the gas is dstributed around the stars (white).

You can now preorder the individual volumes published by Cambridge University Press* (will ship in December 2025).*	ASTRONOMY TEXTBOOK Quasar Absorption Lines Volume 1: Introduction, Discoveries, and Methods Volume 2: Astrophysics, Analysis, and Modeling This advanced textbook is suitable for advanced undergraduate students, graduate students, and seasoned researchers in the field. Together, the two volumes provide a comprehensive and detailed treatment of the topic of quasar absorption lines, including its historical development, scientific findings, theoretical foundations, and methods of analysis.
	Volume 1: Introduction Discoveries, and Methods ($120) This volume chronicles six decades of quasar spectroscopy. The book details the nature of the Lyα forest, Lyman limit systems, damped Lyα absorbers, deuterium (D/H), 21-cm absorbers, HI and HeII reionization, the WHIM, and the multiple ionization phases of metal line absorbers. Galaxies and their connections to these absorbers are treated in depth, as are the taxonomy and classes of AGN/quasar spectra and their associated absorption lines. (695 pages,227 figures; 2575 references) PREORDER: ISBN-10: 0521867606 ; ISBN-13: 978-0521867603 Link: @ Cambridge University Press Link: @ Amazon
	Volume 2: Astrophysics, Analysis, and Modeling ($100) This volume treats the theory and analysis of absorption lines, including the physics of atomic transitions, gas and ionization physics, the cosmological model, radiative transfer, spectrograph design, analysis of spectra, and multi-component, multiphase chemical-ionization modeling. Pragmatic approaches to conducting and assessing absorber counts in large absorption line surveys is presented. Throughout, objective analysis methods are emphasized and presented for clarity of practical application. (621 pages, 188 figures; 518 references) PREORDER: ISBN-10: 1009715216 ; ISBN-13: 978-10099715218 Link: @ Cambridge University Press Link: @ Amazon