This book provides an introduction to the physics of interstellar gas in the Galaxy. It deals with the diffuse interstellar medium which supplies a complex environment for exploring the neutral gas content of a galaxy like the Milky Way and the techniques necessary for studying this non-stellar component. After an initial exposition of the phases of the interstellar medium and the role of gas in a spiral galaxy, the authors discuss the transition from atomic to molecular gas. They then consider basic radiative transfer and molecular spectroscopy with particular emphasis on the molecules useful for studying low-density molecular gas. Observational techniques for investigating the gas and the dust component of the diffuse interstellar medium throughout the electromagnetic spectrum are explored emphasizing results from the recent Herschel and Planck missions. A brief exposition on dust in the diffuse interstellar medium is followed by a discussion of molecular clouds in general and high-latitude molecular clouds in particular. Ways of calibrating CO observations with the molecular hydrogen content of a cloud are examined along with the dark molecular gas controversy. High-latitude molecular clouds are considered in detail as vehicles for applying the techniques developed in the book. Given the transient nature of diffuse and translucent molecular clouds, the role of turbulence in the origin and dynamics of these objects is examined in some detail. The book is targeted at graduate students or postdocs who are entering the field of interstellar medium studies.

Describing interstellar matter in our galaxy in all of its various forms, this book also considers the physical and chemical processes that are occurring within this matter. The first seven chapters present the various components making up the interstellar matter and detail the ways that we are able to study them. The following seven chapters are devoted to the physical, chemical and dynamical processes that control the behaviour of interstellar matter. These include the instabilities and cloud collapse processes that lead to the formation of stars. The last chapter summarizes the transformations that can occur between the different phases of the interstellar medium. Emphasizing methods over results, The Interstellar Medium is written for graduate students, for young astronomers, and also for any researchers who have developed an interest in the interstellar medium.

This volume describes the current state of the art in research aimed at unraveling the carriers of the enigmatic diffuse interstellar bands (DIBs). The DIBs are a set of hundreds of absorption bands that are seen from the near-ultraviolet to near-infrared wavelengths. Their interstellar origin is well established, but the precise chemical identity of the DIB carriers remains to date one of the greatest unsolved mysteries in astronomical spectroscopy. These proceedings of IAU Symposium 297 include more than 70 contributions that cover a wide range of topics in observational astronomy and astrophysics; laboratory astrophysics and spectroscopy; astrochemistry; and theoretical, experimental and computational chemistry. This interdisciplinary overview contains all the required background material to make the volume an ideal starting point for researchers and graduate students to learn about the various aspects of DIBs and related topics.

This book provides an introduction to the physics of interstellar gas in the Galaxy. It deals with the diffuse interstellar medium which supplies a complex environment for exploring the neutral gas content of a galaxy like the Milky Way and the techniques necessary for studying this non-stellar component. After an initial exposition of the phases of the interstellar medium and the role of gas in a spiral galaxy, the authors discuss the transition from atomic to molecular gas. They then consider basic radiative transfer and molecular spectroscopy with particular emphasis on the molecules useful for studying low-density molecular gas. Observational techniques for investigating the gas and the dust component of the diffuse interstellar medium throughout the electromagnetic spectrum are explored emphasizing results from the recent Herschel and Planck missions. A brief exposition on dust in the diffuse interstellar medium is followed by a discussion of molecular clouds in general and high-latitude molecular clouds in particular. Ways of calibrating CO observations with the molecular hydrogen content of a cloud are examined along with the dark molecular gas controversy. High-latitude molecular clouds are considered in detail as vehicles for applying the techniques developed in the book. Given the transient nature of diffuse and translucent molecular clouds, the role of turbulence in the origin and dynamics of these objects is examined in some detail. The book is targeted at graduate students or postdocs who are entering the field of interstellar medium studies.