Opis: Terahertz Astronomy - Christopher Walker

A Powerful Window into Cosmic Evolution Terahertz (THz) observations of interstellar atoms, molecules, and dust serve as powerful probes of the conditions within the interstellar medium that permeates our galaxy, providing insights into the origins of stars, planets, galaxies, and the Universe. Taking a cross-disciplinary approach to the subject, Terahertz Astronomy explores THz astrophysics and the technologies that make this rapidly evolving field possible. The first four chapters of the book discuss the origin and interpretation of THz light in astrophysical sources. The remaining five chapters present an overview of the technologies used to collect and detect THz light. Every chapter contains worked-out examples and exercises. The author explains each topic as intuitively as possible and includes the equations needed for real-life astrophysical applications. In just a few years, the number of active THz researchers has substantially grown due to increased interest in terrestrial remote sensing at THz frequencies. This book provides researchers with both the background science and technology to interpret THz observations and design, build, and deploy THz astronomical instrumentation. "This comprehensive, well-written book was a pleasure to read, an absolute must for anyone interested in learning about cutting-edge technologies and techniques revolutionizing our modern view of the Universe, and it is destined to become a standard reference work for astronomers and technologists." -Professor Glenn White, The Open University "This excellent book fills a huge hole in the literature in observational terahertz astronomy. No other existing text covers the essentials of terahertz astronomy instrumentation and techniques as applied to the study of the interstellar medium. It is sure to become an essential text for those who work in the field." -Christopher Groppi, School of Earth and Space Exploration, Arizona State University "... a wonderful book, combining an insightful overview of the interstellar medium with a description of the most important techniques used to study this component of galaxies and how new stars form. It's particularly timely, with the availability of powerful new tools, including the ALMA array, the SOFIA airborne observatory, and a range of planned and proposed suborbital and space missions in the terahertz range." -Paul F. Goldsmith, Jet Propulsion Laboratory, California Institute of Technology and Herschel Space Observatory "This valuable and well-written textbook by Professor Christopher Walker helps to fill a gap in the literature describing the interstellar medium at terahertz frequencies. There are very few textbooks that discuss the medium from the observer's point of view, showing how to determine its physical parameters from the output of the detectors. Also discussed are the operations of mixer and bolometer detectors." -Thomas G. Phillips, John D. MacArthur Professor of Physics Emeritus, California Institute of Technology "... a fundamental source for astronomers and engineers who wish to understand the physical principles and detection techniques." -Jonathan Williams, University of Hawaii "Walker's book is incredibly timely: it introduces the basics of terahertz data but also explains the instrumentation at the level all observers need to know, and does so in friendly but, most importantly, crystal-clear prose." -George H. Rieke, Regents' Professor of Astronomy, University of Arizona "... an essential resource for all astrophysicists and experimental physicists seeking to exploit the opportunities of this last frontier in astronomy." -Michael Burton, University of New South WalesThe Interstellar Medium at Terahertz Frequencies Introduction ISM Components of the Milky Way Lifecycle of the ISM Probing the Lifecycle of the ISM THz SEDs Conclusion THz Radiative Transfer Basics and Line Radiation Equation of Radiative Transfer Solution to the Equation of Radiative Transfer under LTE (Local Thermodynamic Equilibrium) Radiative Transfer of Rotational Transitions of Linear Molecules in LTE Non-LTE Approach Conclusion THz Continuum Emission Introduction THz Spectral Energy Distributions Deriving Dust Optical Depth, Column Density, and Mass Temperature and Density Distributions Dust Energy Balance in Clouds Dust-Gas Coupling Dust Polarization: Origin and Measurement Conclusion Simple Radiative Transfer Model Introduction Geometry Source Physical Conditions Lines of Sight Model Equation of Transfer LTE Radiative Transfer with Hydrodynamic Simulations Non-LTE Radiative Transfer with Hydrodynamic Simulations Going Further THz Optical Systems Introduction: Source-Beam Coupling QED and Maxwell Origin of a Single-Aperture Diffraction Pattern (QED) Gaussian Beam Optics Focusing Gaussian Beams Intercepting Gaussian Beams Illuminating THz Telescopes Conclusion THz Coherent Detection Systems Introduction Superheterodyne Receivers Receiver Noise Temperature Noise Temperature of THz Optical Systems THz Mixer Architectures and Noise IF Amplifiers Effective Temperature Measurement of THz Components THz Mixers THz Local Oscillators Receiver Back-Ends Receiver Stability and Allan Time Heterodyne Array Considerations Summary Incoherent Detectors Introduction Bolometer Basics Semiconductor Bolometers Superconducting Incoherent Background Noise Limited Operation Instrument Noise Limited Operation Sensitivity Requirements Comparing Heterodyne and Incoherent Detector Sensitivity Incoherent Array Considerations Conclusion THz Observing Techniques Introduction Observing Strategies Receiver Calibration Estimating Atmospheric Optical Depth THz Brightness Temperature of Planetary Bodies Conclusion THz Interferometry Introduction Simple Adding Interferometer Phase Switched Interferometer Correlation Interferometer Phasor Equation for Interferometry Aperture Synthesis of Extended Sources Filling-in uv Space Transforming the Visibility Function Map Noise Level Phase Closure or Self-Calibration Phase Error at THz Frequencies Answers to Problems Appendix 1: Timeline of Thz Technology Appendix 2: More Thz Transitions of Atoms and Molecules Appendix 3: Commonly Used Physical and Astronomical Quantities Appendix 4: Useful Radiative Transfer Expressions Appendix 5: Commonly Used Quasi-Optical Expressions Appendix 6: Useful Heterodyne Receiver Expressions References appear at the end of each chapter.

Szczegóły: Terahertz Astronomy - Christopher Walker

Tytuł: Terahertz Astronomy
Autor: Christopher Walker
Producent: CRC Press Inc.
ISBN: 9781466570429
Rok produkcji: 2015
Ilość stron: 351
Oprawa: Twarda
Waga: 0.98 kg

Recenzje: Terahertz Astronomy - Christopher Walker