HIFI Observers' Manual
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HIFI Observers' Manual

Announcement of Opportunity for Key Programmes

version 1.1, 28-May-2007

HERSCHEL-HSC-DOC-0784, version 1.1

28-May-2007

Revision History
Revision version 1.0
Initial version

Table of Contents

1. The HIFI Instrument Observer's Manual

1.1. Purpose of this Document
1.2. Acknowledgements

2. HIFI Instrument Description

2.1. Instrument and Concept

2.1.1. What is HIFI?
2.1.2. How Does HIFI Work?

2.2. Instrument Configuration

2.3. HIFI Focal Plane Unit

2.3.1. The Common Optics Assembly
2.3.2. The Beam Combiner Assembly (Diplexer Unit)
2.3.3. HIFI Mixers
2.3.4. The Focal Plane Chopper
2.3.5. The Calibration Source Assembly

2.4. The HIFI Signal Chain

2.5. HIFI Spectrometers

2.5.1. The Wide Band Spectrometer (WBS)
2.5.2. The High Resolution Spectrometer (HRS)

3. HIFI Scientific Capabilities

3.1. What Science Is Possible With HIFI?

3.1.1. HIFI's Scientific Objectives

3.2. Primary Instrument Characteristics

3.3. General Instrument Description

3.4. Mixer Performance

3.4.1. System Temperatures
3.4.2. Mixer Stabilities
3.4.3. Sensitivity Variations Across the IF Band

3.5. Available Spectrometer Setups

3.5.1. Wide Band Spectrometers (WBSs)
3.5.2. High Resolution Spectrometers (HRSs)

4. Observing with HIFI

4.1. Introduction

4.2. The HIFI Observing Modes

4.2.1. Modes of the Single Point AOT I
4.2.2. Modes of the Mapping AOT II
4.2.3. Modes of the Spectral Scan AOT III

4.3. "Grouping" or "Clustering" of Observations

4.4. Solar System Targets

5. The Framework for HIFI Calibration

5.1. Introduction:

5.2. The Intensity Calibration of HIFI

5.2.1. Context

5.3. The HIFI Calibration Scheme

5.3.1. Load Calibration
5.3.2. OFF calibration
5.3.3. Differencing observations:
5.3.4. Non-linearity:
5.3.5. Blank-sky contribution:

5.4. The frequency calibration of HIFI:

5.4.1. Context:
5.4.2. Frequency accuracy:
5.4.3. Frequency calibration:
5.4.4. Frequency resolution:
5.4.5. Spurious responses:

5.5. The Spatial Response Calibration of HIFI:

5.5.1. Context:
5.5.2. HIFI/Herschel spatial response:

5.6. Summary: overall calibration of HIFI and error budget:

5.6.1. Strategy summary:
5.6.2. Error budget

6. Using HSpot to Create HIFI Observations

6.1. Overview

6.2. HSpot Components for Setting Up a HIFI Observation

6.2.1. Working with A HIFI Pointed or Mapping Observation Template
6.2.2. HIFI Spectral Scan AOT

6.3. Example HIFI Single Point Observation Setups

6.3.1. Example 1: Observing the [CII] line using Frequency Switch in a photodissociation region
6.3.2. Example 2: A Dual Beam Switch (DBS) mode AGB Observation

6.4. Example Setup of a HIFI Mapping AOR

6.4.1. Example 3: Scan Mapping of the Spectral Lines CO(7-6) and CI(2-1) in the Centre of M51 .

6.5. Example Setup of a HIFI Spectral Scan Observation

6.5.1. Example 4: Spectral Survey of a Hot Core.

7. Pipeline and Data Products Description

7.1. Data to be Passed on to the User

7.2. Additional Observatory Meta Data

7.3. Example HIFI data products

7.3.1. Level 0 products
7.3.2. Level 1 products

7.4. Pipeline Processing

7.4.1. WBS Pipeline Processing Steps
7.4.2. HRS Pipeline Processing Steps

7.5. Deconvolution Processing of Spectral Scan Data

7.5.1. Solving the Deconvolution Problem

8. References:

A. Change Log

A.1. Updates for this Edition

List of Figures

2.1. Dual sideband spectrum superposition
2.2. Dual sideband spectrum changes with LO frequency
2.3. General HIFI component diagram.
2.4. HIFI Focal Plane Unit (FPU).
2.5. Back side of the HIFI FPU.
2.6. HIFI telescope relay optics.
2.7. Channel splitting optics
2.8. Beamsplitter and diplexer mixing with sample diplexer unit.
2.9. A HIFI mixer sub-assembly.
2.10. The HIFI Focal Plane Chopper (FPC).
2.11. The HIFI signal chain.
3.1. Water in Orion
3.2. Molecular lines in the star IRC+10 216
3.3. Double sideband system temperatures of HIFI mixers.
3.4. Variation of IF sensitivity
3.5. Example of the use of high resolution spectroscopy in the Orion-Irc2 region.
4.1. Overview of available AOT observing modes.
4.2. Timeline of HIFI position switch AOT.
4.3. HIFI Dual Beam Switch positions on the sky.
4.4. Timeline of the HIFI Dual Beam Switch observing mode.
4.5. Timeline for HIFI Frequency Switch observations.
4.6. Timeline for the HIFI load chop observing mode.
4.7. Timeline of the path on the sky for a HIFI OTF mapping mode. The green dots indicate regular data readouts of the spectrometers. The OFF position is returned to at the end of an integer number of scan legs. This is typically 1 or 2 except in the case of small OTF maps.
4.8. Spectral scan frequency grouping
6.1. HSpot "Observation" menu on the "Observations" screen.
6.2. HIFI pointed observation AOT window.
6.3. HIFI mixer band selection.
6.4. HIFI redshift selection.
6.5. HIFI HRS resolution choice.
6.6. HIFI Frequencies window.
6.7. Frequency Editor window components.
6.8. Spectral line identification via mouse click.
6.9. Example HIFI frequency editor setup
6.10. HIFI pointed mode selection.
6.11. HIFI position switch mode.
6.12. HIFI mapping mode selection.
6.13. HIFI raster map setup.
6.14. The spectral scan AOT setup window.
6.15. Time estimator settings window.
6.16. Time estimator return information window.
6.17. Observation breakdown information .
6.18. Target name resolution for example 1.
6.19. Instrument setup screen for Example 1.
6.20. Spectral line selection for Example 1.
6.21. The H₂O(331-404) line is shown available under the dark area to top left.
6.22. Final frequency selection for Example 1 with [CII] position marked. Note that the [CII] line is NOT at the centre of the sideband, this is due to the fact that there is slope to the sensitivity within the IF for bands 6 and 7. The position shown is believed to be the best for sensitivity and coverage (see the Chapter 3, HIFI Scientific Capabilities for details).
6.23. Selection of frequency switch with offset.
6.24. Setup of time estimate for the example observation.
6.25. Appearance of the final AOR on the "Observations" screen.
6.26. Observation overlaid on Band A MSX image (8 microns).
6.27. Instrument setup for Example 2.
6.28. Frequency editor initial setup on water line.
6.29. Final setup of the frequency editor.
6.30. Frequency editor setup for the second set of water lines.
6.31. Image overlay of the two dual beam switch AOR examples on a DSS image of the region.
6.32. Instrument settings prepared for example 3.
6.33. Frequency editor setup for the M51 example.
6.34. Final mapping mode setup for example 3.
6.35. Overlay of AOR example 3 on DSS image.
6.36. Filled in AOT for the example spectral scan observation.
7.1. Typical level 0 raw calibration data for HIFI
7.2. Typical level 0 raw science data for HIFI
7.3. Typical calibrated scans
7.4. Level 1 science data with velocity scale.
7.5. Calibrated frequency switch scans
7.6. Redundant LO settings.
7.7. MEM deconvolution examples

List of Tables

3.1. HIFI frequency coverage
3.2. Currently assumed stability (Allan) times for differencing measurements made with HIFI
3.3. List of HRS configurations available in each polarization
5.1. Frequency accuracy budget
5.2. HIFI resolutions using the WBS and HRS in two of its modes.
5.3. HIFI beam efficiencies
5.4. Systematic errors at 500GHz (band 1)
5.5. Systematic errors at 1900GHz (band 7)