Cover -- Half-title -- Title -- Copyright -- Contents -- Contributors -- Participants -- Preface -- Acknowledgements -- 1. What can emission lines tell us? -- 1.1. Introduction -- 1.2. Generalities -- 1.2.1 Line-production mechanisms -- 1.2.1.1 Recombination -- 1.2.1.2 Collisional excitation -- 1.2.1.3 Fluorescent excitation -- 1.2.1.4 Some hints -- 1.2.1.5 Atomic data -- 1.2.2 The transfer of radiation -- 1.2.2.1 The transfer of Lyman-continuum photons emitted by the ionizing source -- 1.2.2.2 The transfer of the ionizing photons produced by the nebula -- 1.2.2.3 The non-ionizing lines emitted by the nebula -- 1.3. Empirical diagnostics based on emission lines -- 1.3.1 Electron temperature and density -- 1.3.2 Ionic and elemental abundances -- 1.3.2.1 Direct methods -- 1.3.2.2 Statistical methods -- 1.3.3 Estimation of the effective temperature of the ionizing stars -- 1.3.4 Determining the star-formation rate -- 1.3.5 How can one distinguish normal galaxies from AGN hosts? -- 1.4. Photoionization modelling -- 1.4.1 Photoionization codes -- 1.4.1.1 One-dimensional photoionization codes -- 1.4.1.2 Three-dimensional photoionization codes -- 1.4.1.3 Other codes -- 1.4.2 Why do we construct photoionization models? -- 1.4.3 How should one proceed? -- 1.4.4 Abundance derivation by tailored model fitting -- 1.4.5 Abundance derivation using grids of models -- 1.4.6 Testing model atmospheres of massive stars using Hii regions -- 1.4.7 A photoionization study of an aspherical nebula using a three-dimensional code: the planetary nebula NGC 7009 -- 1.4.8 The interpretation of data from integral field spectroscopy -- 1.5. Questions pending -- 1.5.1 Correction for reddening, underlying stellar absorption and aperture effects -- 1.5.2 Escape of ionizing radiation -- 1.5.3 The importance of the stellar energy distribution -- 1.5.4 Dust.

1.5.5 Temperature fluctuations and the ORL/CEL discrepancy -- 1.5.6 Shocks and related issues -- Appendix: Lists of useful lines and how to deal with them -- Acknowledgments -- REFERENCES -- 2. The observer's perspective: Emission-line surveys -- 2.1. Introduction -- 2.2. Notations, definitions, and other useful concepts -- 2.2.1 Redshift -- 2.2.2 Narrow-band filters and dispersers -- 2.2.3 The signal-to-noise ratio -- 2.2.4 Source parameters -- 2.2.5 Line width -- 2.2.6 Equivalent width -- 2.3. Methodology of emission-line surveys -- 2.3.1 Narrow-band imaging -- 2.3.2 Spectroscopic surveys -- 2.3.3 The sky background -- 2.3.4 Planning for a survey -- 2.4. Lyman-α surveys -- 2.4.1 The search for galaxies at very high redshifts -- 2.4.2 Clusters and clustering from line-emission surveys -- 2.4.3 Lyman-α surveys as probes of the cosmic reionization -- 2.4.4 Serendipitous discoveries -- 2.5. Surveys for other emission lines -- REFERENCES -- 3. The astrophysics of early galaxy formation -- 3.1. Preamble -- 3.2. The dark ages -- 3.2.1 Cosmological preliminaries -- 3.2.2 Physics of recombination -- 3.2.3 Coupling of gas and radiation -- 3.2.4 Hydrogen molecules in the early Universe -- 3.3. The emergence of cosmic structure -- 3.3.1 Linear theory -- 3.3.2 Statistics of density fields -- 3.3.3 Spherical collapse -- 3.3.4 Dark-halo mergers -- 3.3.5 Assembly history of a Milky Way halo -- 3.3.6 Smallest SUSY-CDM microhalos -- 3.4. The dawn of galaxies -- 3.4.1 Uncertainties in the power spectrum -- 3.4.2 First baryonic objects -- 3.4.3 21-cm signatures of the neutral IGM -- 3.4.4 Concluding remarks -- Acknowledgments -- REFERENCES -- 4. Primeval galaxies -- 4.1. Introduction -- 4.2. Population III stars and galaxies: a "top-down" theoretical approach -- 4.2.1 Primordial star formation -- 4.2.2 Primordial stars: properties.

4.2.3 Primordial stars and galaxies: observable properties -- 4.2.4 Final fate -- 4.2.5 Nucleosynthesis and abundance pattern -- 4.2.6 Dust at high z -- 4.3. Lya physics and astrophysics -- 4.3.1 ISM emission and "escape" -- 4.3.2 Lyα: the observational problem -- 4.3.3 Lessons from local starbursts -- 4.3.4 Lyα radiation transfer -- 4.3.4.1 Basic line-formation processes and examples -- 4.3.4.2 Lyα transfer with dust -- 4.3.4.3 Lyα transfer: geometrical effects -- 4.3.5 Lessons from Lyman-break galaxies -- 4.3.6 Lyα through the intergalactic medium -- 4.3.7 Lyα from sources prior to reionization -- 4.3.8 The Lyα luminosity function and reionization -- 4.4. Distant/primeval galaxies: observations and main results -- 4.4.1 Search methods -- 4.4.2 Distant Lyα emitters -- 4.4.2.1 Population III signatures in LAEs? -- 4.4.2.2 Dust properties of high-z LAEs -- 4.4.3 Lyman-break galaxies -- 4.4.3.1 i-dropout(z 6)samples -- 4.4.3.2 Optical-dropout samples… -- 4.4.3.2 Optical-dropo… -- 4.4.4 What next? -- Acknowledgments -- REFERENCES -- 5. Active galactic nuclei -- 5.1. Introduction -- 5.2. The discovery and nature of active galaxies -- 5.3. Identifying active galaxies -- 5.4. A diverse taxonomy -- 5.5. The structure and physics of AGNs -- 5.5.1 An overview -- 5.5.2 The supermassive black hole -- 5.5.2.1 Physical considerations -- 5.5.2.2 Observational evidence -- 5.5.3 The accretion disk -- 5.5.3.1 Physical considerations -- 5.5.3.2 Observational evidence -- 5.5.4 The broad-line region -- 5.5.5 The narrow-line region -- 5.5.6 The "obscuring torus" -- 5.6. Distinguishing AGNs from other emission-line galaxies -- 5.7. The theory of reverberation mapping -- 5.7.1 The nature of continuum variability -- 5.7.2 Reverberation-mapping assumptions -- 5.7.3 The transfer equation -- 5.7.4 Velocity-delay maps -- 5.7.5 Recovering velocity-delay maps from real data.

5.8. Reverberation-mapping results -- 5.8.1 The size of the broad-line region -- 5.8.2 Ionization stratification -- 5.8.3 The BLR radius-luminosity relationship -- 5.8.4 Black-hole masses -- 5.9. An evolving view of the BLR -- 5.9.1 The BLR gas: discrete clouds or a continuous flow? -- 5.9.2 Physical conditions in the BLR -- 5.9.3 The mass of the BLR -- 5.9.4 The kinematics of the BLR -- 5.9.5 Dust and the BLR -- 5.10. Unification issues and the NLR -- 5.10.1 The geometry of the obscuring torus -- 5.10.2 Type 2 quasars -- 5.10.3 The NLRs in Type 1 and Type 2 AGNs -- 5.11. Cosmological implications -- 5.11.1 The space density of AGNs -- 5.11.2 The luminosity function -- 5.11.3 Masses of distant quasars -- Acknowledgments -- REFERENCES -- 6. Chemical evolution -- 6.1. Basic assumptions and equations of chemical evolution -- 6.1.1 The basic ingredients -- 6.1.2 The star-formation rate -- 6.1.3 The initial mass function -- 6.1.4 The infall rate -- 6.1.5 The outflow rate -- 6.1.6 Stellar evolution and nucleosynthesis: the stellar yields -- 6.1.7 Type Ia SN progenitors -- 6.1.8 Yields per stellar generation -- 6.1.9 Analytical models -- 6.2. The Milky Way and other spirals -- 6.2.1 The Galactic formation timescales -- 6.2.2 The two-infall model -- 6.2.3 Common conclusions from Milky Way models -- 6.2.4 Abundance gradients from emission lines -- 6.2.5 Abundance gradients in external galaxies -- 6.2.6 How to model the Hubble sequence -- 6.2.7 Type Ia SN rates in various types of galaxy -- 6.2.8 A time-delay model for galaxies of various types -- 6.3. Interpretation of abundances in dwarf irregulars -- 6.3.1 Properties of dwarf irregular galaxies -- 6.3.2 Galactic winds -- 6.3.3 Results on DIGs and BCGs from purely chemical models -- 6.3.4 Results from chemo-dynamical models: IZw18 -- 6.4. Elliptical galaxies-quasars-ICM enrichment -- 6.4.1 Ellipticals.

6.4.2 Chemical properties -- 6.4.3 Scenarios for galaxy formation -- 6.4.4 The ellipticals-quasars connection -- 6.4.5 The chemical evolution of QSOs -- 6.4.6 The chemical enrichment of the ICM -- 6.4.7 Conclusions on the enrichment of the ICM -- Acknowledgments -- REFERENCES -- 7. Galactic sources of emission lines -- 7.1. Introduction -- 7.2. Overview of infrared emission lines -- 7.2.1 Why infrared emission lines? -- 7.2.2 Observing in the infrared waveband -- 7.2.2.1 Infrared observing technology -- 7.2.2.2 The infrared atmosphere -- 7.2.3 Important infrared emission lines -- 7.2.3.1 Hydrogen emission in the infrared -- 7.2.3.2 Metal lines -- 7.2.3.3 Molecular lines -- 7.3. Galactic nebular sources of emission lines -- 7.3.1 H II regions -- 7.3.2 Planetary nebulae -- 7.3.2.1 PNe emission-line basics -- 7.3.2.2 Morphology and outflow kinematics -- 7.3.3 Supernova remnants -- 7.4. Galactic stellar sources of emission lines -- 7.4.1 Young stellar objects -- 7.4.1.1 T Tauri stars -- 7.4.1.2 Herbig-Haro Objects -- 7.4.1.3 Young massive stars -- 7.4.2 Massive stars -- 7.4.2.1 Be and B[e] stars -- 7.4.2.2 Luminous blue variables -- 7.4.2.3 Wolf-Rayet stars -- 7.4.3 Magnetospherically active stars -- 7.4.4.1 Cataclysmic variables -- 7.4.4.2 X-ray binaries -- REFERENCES -- 8. Narrow-band imaging -- 8.1. Introduction -- 8.2. Extended-source imaging -- 8.2.1 Sky subtraction -- 8.2.2 Flux calibration -- 8.2.3 Equations for calibration -- 8.2.4 Continuum subtraction -- 8.3. Imaging in the airglow-windows range -- 8.3.1 Fringing -- 8.3.2 Fringing removal using the package mscred -- 8.4. Selection of candidates and line flux -- Acknowledgments -- REFERENCES -- 9. Long-slit spectroscopy -- 9.1. Long-slit spectroscopy -- 9.2. Long-slit spectra -- 9.2.1 Signal-to-noise calculations -- 9.3. Effects to correct in a long-slit spectrum.

9.3.2 Flat-field and illumination corrections.