Physical Principles of Astronomical Instrumentation

Description

Cover Half Title Series Page Title Page Copyright Page Table of Contents Preface Authors Chapter 1 Review of Electromagnetic Radiation 1.1 Introduction 1.2 Mathematical Description of Waves 1.3 Maxwell’s Equations 1.4 Electromagnetic Waves 1.5 Plane EM Waves 1.6 Energy in EM Waves 1.7 Wave Particle Duality 1.8 Interaction of EM Radiation with Charged Particles 1.9 Complex Number Representation of Waves 1.10 Superposition and Wave Interference 1.11 Radiative Transfer 1.11.1 Flux, Flux Density, and Intensity 1.11.2 The Equation of Radiative Transfer 1.11.3 Emission Only 1.11.4 Absorption Only 1.11.5 Thermal Equilibrium 1.11.6 Thermal Emission from a Semi-Transparent Region 1.11.7 Transmission of the Earth’s Atmosphere 1.12 Polarisation 1.12.1 Linear, Circular, and Elliptical Polarisation 1.12.2 Stokes Parameters Chapter 2 Astrophysical Radiation 2.1 Astrophysical Radiation Mechanisms 2.2 Black Body Radiation and the Planck Function 2.2.1 Rayleigh–Jeans and Wien Regions 2.2.2 Wien’s Displacement Law 2.2.3 Stefan’s Law 2.2.4 Emissivity 2.3 Free–Free Radiation 2.4 Non-Thermal Emission Mechanisms: Cyclotron and Synchrotron Radiation 2.5 Quantum Transitions 2.5.1 Atomic Transitions 2.5.2 Molecular Vibrational Transitions 2.5.3 Molecular Rotational Transitions 2.5.4 Vibrational-Rotational Transitions 2.5.5 Line Broadening 2.5.5.1 Collisional (Pressure) Broadening 2.5.5.2 Thermal (Doppler) Broadening 2.5.6 Spectral Line Databases 2.5.7 γ-Ray Line Emission 2.6 Polarised Radiation in Astronomy Chapter 3 Interaction of Electromagnetic Radiation with Matter 3.1 Radio Wavelengths (λ >~ 1mm) 3.1.1 The Earth’s Ionosphere 3.1.2 Antennas 3.1.3 Detection of the Intercepted Radiation 3.2 Infrared-Optical-UV Wavelengths (λ = 1 mm–30 nm) 3.2.1 Photon Absorption Mechanisms 3.2.2 Electron Promotion in Semiconductors 3.2.3 The Photoelectric Effect 3.3 X-Ray and γ-Ray Wavelengths 3.3.1 Photoelectric Interaction 3.3.2 The Compton Effect 3.3.3 Electron-Positron Pair Production 3.3.4 Mass Attenuation Coefficient 3.4 The Effects of the Earth’s Atmosphere 3.4.1 Atmospheric Absorption 3.4.2 Atmospheric Emission 3.4.3 Atmospheric Turbulence and Seeing 3.4.4 Earth-Based and Space-Borne Observatories Chapter 4 Telescopes and Optical Systems 4.1 Introduction 4.2 Telescope Configurations 4.3 Telescope Mounting Methods 4.4 Telescope Optics 4.4.1 Lens Optics 4.4.2 Mirror Optics 4.4.3 The Plate Scale 4.4.4 Telescope Throughput 4.5 Optical Aberrations 4.5.1 Spherical Aberration 4.5.2 Coma 4.5.3 Astigmatism 4.5.4 Field Curvature 4.5.5 Distortion 4.5.6 Chromatic Aberration 4.6 Diffraction 4.6.1 The Rayleigh Criterion 4.6.2 Beam Profile or Point Spread Function 4.6.3 Strehl Ratio 4.7 Fourier Optics 4.8 Spatial Interferometry Chapter 5 Key Concepts in Astronomical Measurement 5.1 Introduction 5.2 Transduction 5.3 The Decibel Scale 5.4 Responsivity 5.5 Response Time (Speed of Response) 5.6 Background Radiation 5.7 Noise and Signal-to-Noise Ratio 5.8 Electrical Filtering and Integration 5.9 Nyquist Sampling 5.10 Linearity 5.11 Dynamic Range 5.12 Types of Measurement: Photometry, Spectroscopy, Spectro-photometry 5.13 Calibration 5.13.1 The Stellar Magnitude System 5.13.2 Standard Filter Bands 5.13.3 Colour Correction Chapter 6 Sensitivity and Noise in Electromagnetic Detection 6.1 Introduction 6.2 An Ideal Photon Detector 6.3 Noise Equivalent Power 6.3.1 Background-Limited NEP 6.4 Efficiency of Photon Detectors 6.4.1 DQE and NEP of an Imperfectly Absorbing but Noiseless Detector 6.5 Photon Shot Noise and Wave Noise 6.6 Background Photon Noise-Limited NEP of a Broadband Detector 6.6.1 NEPph for a Photon-Counting Detector 6.6.2 NEPph for Broadband Power Detector 6.7 Additional Sources of Noise 6.7.1 Thermal Noise from a Resistor 6.7.2 Electron Shot Noise 6.7.3 Generation-Recombination Noise 6.7.4 Phonon Noise 6.7.5 1/f - Noise 6.7.6 kTC Noise 6.7.7 Interference 6.7.8 Microphonic Noise 6.8 Combination of Noise from Several Sources 6.8.1 Overall Noise and NEP 6.9 Optimising a System for Best Sensitivity 6.9.1 Choosing the Signal Frequency or Frequency Band 6.9.2 Choosing the Post-Detection Bandwidth 6.9.3 Minimising Noise from the Detector and Its Readout and Signal-Processing Electronics 6.10 Noise Equivalent Flux Density Chapter 7 Astronomical Spectroscopy 7.1 Introduction 7.2 Spectrometer Types 7.3 Prism Spectrometers 7.4 Grating Spectrometers 7.4.1 The Grating Equation and Grating Dispersion 7.4.2 Grating Response to a Monochromatic Source 7.4.3 Spectral Resolving Power 7.4.4 Free Spectral Range and Order-Sorting 7.4.5 Effect of Finite Slit Width 7.4.6 Blazed Gratings and Grating Efficiency 7.4.7 Optical Matching between an Astronomical Source and a Grating Spectrometer 7.4.8 The Echelle Spectrograph 7.4.9 Grisms 7.5 Fabry-Perot (FP) Spectrometers 7.5.1 The Fabry-Perot Interferometer 7.5.2 Free Spectral Range and Resolving Power 7.5.3 Fabry-Perot Spectrometers 7.5.4 Effects of Plate Absorption and Other Imperfections 7.5.5 Rejection of Unwanted Orders 7.6 Fourier Transform Spectrometers 7.6.1 The Michelson Interferometer as a Fourier Transform Spectrometer 7.6.2 Spectral Sampling 7.6.3 Spectral Resolution and the Instrument Response Function 7.6.4 Effect of a Non-Parallel Beam on Spectral Resolving Power 7.6.5 FTS Operation and Data Reduction 7.7 Advantages and Disadvantages of Different Spectrometer Types 7.8 Grating Spectrometer Instruments 7.8.1 Integral Field Units (IFU) and Multi-Object Spectrometers (MOS) Chapter 8 Radio Instrumentation 8.1 Introduction 8.2 Antennas 8.2.1 Antenna Beam Pattern 8.2.2 Gaussian Telescope Illumination 8.2.3 Antenna Efficiencies 8.3 Radio Receivers 8.3.1 Power Received by a Radio Antenna 8.3.2 The Total Power Radiometer 8.3.3 System Temperature 8.3.4 The Superheterodyne Receiver 8.3.5 The Superheterodyne Total Power Receiver 8.3.6 Quantum-Limited System Temperature 8.3.7 Minimum Detectable Temperature and Power 8.4 Mixers and Amplifiers 8.4.1 The Schottky Diode Mixer 8.4.2 Superconductor-Insulator-Superconductor (SIS) Mixers 8.4.3 Hot Electron Bolometer Mixers 8.4.4 High Electron Mobility Transistors 8.5 Local Oscillators 8.6 IF Spectrometers 8.6.1 The Multichannel (Filter Bank) Spectrometer 8.6.2 The Acousto-Optic Spectrometer (AOS) 8.6.3 The Digital Autocorrelation Spectrometer 8.6.4 The Direct FFT Spectrometer 8.7 Radio Observations 8.7.1 Source Antenna Temperature 8.7.2 Sensitivity to a Point Source 8.7.3 Calibration Methods 8.8 Radio Interferometry 8.8.1 The Two-Element Radio Interferometer 8.8.2 The Effect of Finite Bandwidth 8.8.3 Fringe-Stopping 8.8.4 Beam Synthesis 8.8.5 Interferometer Observation of an Extended Source 8.8.6 The uv Plane and Aperture Synthesis 8.8.7 Interferometer Sensitivity 8.9 Case Studies 8.9.1 The 4-mm Receiver on the Green Bank Telescope 8.9.2 The GREAT Spectrometer on Board the SOFIA Airborne Observatory 8.9.3 The MeerKAT Radio Interferometer Chapter 9 Far-Infrared to Millimetre Wavelength Instrumentation 9.1 Introduction 9.2 Direct Detection Instruments 9.3 Bolometric Detectors 9.3.1 Bolometer Responsivity 9.3.2 Bolometer Time Constant 9.3.3 Bolometer Noise and NEP 9.3.4 Dependence of Achievable Bolometer NEP on Operating Temperature 9.3.5 Semiconductor Bolometers 9.3.6 Semiconductor Bolometer Readout Electronics 9.3.7 TES Bolometers 9.3.8 TES Bolometer Readout Electronics 9.4 Kinetic Inductance Detectors 9.5 Choice of Bolometric and KID Detectors for the Far Infrared and Submillimetre 9.6 Photoconductive Detectors 9.6.1 Responsivity 9.6.2 Dark Current 9.6.3 Noise 9.6.4 NEP 9.6.5 Photoconductor Readout Electronics 9.7 Choice of Photoconductors for the Far Infrared 9.8 Coupling FIR and Submillimetre Detector Arrays to the Telescope 9.8.1 Antenna-Coupled Arrays 9.8.2 Absorber-Coupled Arrays 9.9 Case Studies 9.9.1 Herschel-SPIRE: A Space-Borne FIR-Submillimetre Camera and Spectrometer 9.9.2 Spitzer-MIPS: A Space-Borne FIR Camera 9.9.3 SCUBA-2: A Ground-Based Submillimetre Camera Chapter 10 Infrared to UV Instrumentation 10.1 Introduction 10.2 Infrared Detectors 10.2.1 Photodiodes 10.2.2 Infrared Photodiode Materials 10.2.3 Infrared Photodiode Arrays 10.2.4 Blocked Impurity Band (BIB) Photoconductive Detectors 10.3 Optical and UV Detectors 10.3.1 Charge-Coupled Devices (CCDs) 10.3.1.1 Charge Transfer and Readout 10.3.1.2 Buried Channel CCDs 10.3.1.3 CCD Quantum Efficiency and Spectral Response 10.3.1.4 CCD Noise 10.3.1.5 Charge Multiplying CCDs 10.3.1.6 CCD Performance Parameters 10.3.1.7 Main Advantages of CCDs 10.3.1.8 CCD Operation 10.3.2 The Photomultiplier Tube 10.3.3 The Microchannel Plate 10.3.4 The Avalanche Photodiode 10.4 Adaptive Optics 10.4.1 Adaptive Optics Systems 10.5 Case Studies 10.5.1 The WFPC 3 Instrument on the Hubble Space Telescope 10.5.2 The K-Band Multi-Object Spectrometer (KMOS) on the ESO-VLT 10.5.3 MICADO – An Imager for the Extremely Large Telescope Chapter 11 X-Ray, γ-Ray, and Astro-Particle Detection 11.1 Introduction 11.2 X-ray CCDs and Fano Noise 11.3 The Proportional Counter 11.4 X-Ray Spectroscopy 11.5 The X-Ray Calorimeter 11.6 Scintillation Detectors 11.7 Semiconductor Detectors: Silicon, Germanium, and Mercury Cadmium Telluride 11.8 X- and γ-Ray Imaging 11.8.1 Grazing Incidence X-Ray Telescopes 11.8.2 Coded Mask Imaging 11.8.3 The Compton Telescope 11.8.4 Pair Creation Detectors 11.9 High-Energy γ-Ray and Cosmic Ray Detection 11.9.1 Extensive Air Showers 11.9.2 Čerenkov Radiation 11.9.3 Extensive Air Shower Observatories 11.10 Cosmic Neutrino Detection 11.11 Case Studies 11.11.1 XMM-Newton and Its Instruments 11.11.2 The Swift Satellite and Its Instruments 11.11.3 The Fermi Large Area Telescope 11.11.4 The VERITAS Čerenkov Telescope Array for High-Energy Gamma-Ray Astronomy 11.11.5 The IceCube Neutrino Observatory Bibliography Index