Intro; Preface; Acknowledgements; Contents; Contributors; Acronyms; Part I Introduction to Low-Frequency Radio Astronomy and the LOFAR Telescope; 1 Introduction to Low Frequency Radio Astronomy; 1.1 Historical Context; 1.1.1 Scientific and Technical Background; 1.1.2 A History of Radio Astronomy; 1.1.3 Review of Radio Interferometry; 1.2 Low Frequency Science; 1.2.1 Cosmic Magnetism; 1.2.2 Epoch of Reionization; 1.2.3 High Energy Cosmic Rays; 1.2.4 Solar Physics and Space Weather; 1.2.5 Surveys; 1.2.6 Transients; 1.2.7 Other Topics; 1.3 Low Frequency Radio Facilities; References

2 LOFAR Overview2.1 Introduction; 2.2 Antennas; 2.3 Observing Bands; 2.4 Configuration; 2.5 Signal Path and Data Flow; 2.6 COBALT: Central Signal Processing; 2.6.1 Correlator Processing Pipeline; 2.6.2 Tied Array Beam Former Processing Pipeline; 2.7 Phased Array Beam Forming; 2.7.1 Beam Patterns; 2.7.2 Grating Responses; 2.7.3 A Hierarchy of Beams; 2.8 Summary; References; 3 LOFAR Station Processing; 3.1 Antennas; 3.1.1 LBA; 3.1.2 HBA; 3.2 Stations; 3.3 Receiver Unit; 3.3.1 HBA Control Modem; 3.3.2 RCU Modes; 3.4 Digital Processing; 3.4.1 Beamlet Processor (BLP)

3.4.2 Subband Statistics (SST)3.4.3 Beamlet Statistics (BST); 3.4.4 Crosslet Statistics (XST); 3.5 Station Clock; References; Part II Fundamentals of LOFAR Data Processing; 4 RFI Flagging, Demixing and Visibilities Compression; 4.1 Best Discretization in Time and Frequency; 4.2 Default Preprocessing Pipeline: DPPP; 4.3 Flagging RFI; 4.3.1 Inspecting Data to Spot RFI; 4.3.2 Flagging Ranges of Data (preflagger); 4.3.3 Automatic Flagging Using AOFlagger; 4.4 Removal of Bright Sources; 4.4.1 Smart Demix; 4.4.2 Averaging Data with DPPP; References; 5 Calibration of LOFAR; 5.1 Introduction

5.2 The Evolving Playing Field for Imaging and Calibration5.3 From Calibration to Self-Calibration; 5.3.1 The Self-Calibration Philosophy; 5.3.2 Calibration Regimes and Unknowns; 5.3.2.1 Modelling of the Sky; 5.3.2.2 Measurement of Positions; 5.3.2.3 Modelling of the Instrument; 5.4 Flux-Density and Spectral Bandpass Calibration; 5.5 Calibration Procedure; 5.5.1 Black Board Self-Calibration: An Introduction; 5.5.2 Specifying the Sky Model; 5.5.3 Calibration Strategies; 5.5.4 Inspecting and Flagging Solutions; 5.5.5 Direction Dependent Calibration; 5.6 Advanced Calibration Techniques

5.6.1 A Facet Calibration Approach5.6.2 A Global Solve Using SAGECal; 5.7 Summary; References; 6 Error Recognition in LOFAR Data; 6.1 Diagnosing Errors in the u,v Plane Compared to the Image Plane; 6.2 Recognising Calibration Errors in the Image Plane; 6.3 Recognising Imaging Errors; 6.4 Wide-Field Imaging Effects; 6.4.1 w-Projection and A-Projection Effects; 6.4.2 Bandwidth-Smearing and Time-Average Smearing; 6.4.3 Sidelobes from Bright Sources in the Field; 6.4.4 Direction Dependent Effects; 6.5 Can You Do Science with It?; References; 7 Ionospheric Effects; 7.1 Introduction