Chapter 2. SPIRE Launch Pad: Data Reduction Overview

Table of Contents

2.1. Data Launch Pad
2.1.1. Obtaining SPIRE data from the archive and importing into HIPE
2.1.2. Looking at your Data
2.2. Photometer Launch Pad
2.2.1. Does the Photometer observation data need re-processing?
2.2.2. Re-processing with the User Pipeline Scripts
2.2.3. Further Analysis
2.3. Spectrometer Launch Pad
2.3.1. Does the observation data need re-processing?
2.3.2. Re-processing with the User Pipeline Scripts
2.3.3. Further Analysis

2.1. Data Launch Pad

2.1.1. Obtaining SPIRE data from the archive and importing into HIPE

This topic is covered in detail in SDRG Section 4.1

Herschel data are stored in ESA's Herschel Science Archive (HSA):

  • Identified with a unique number known as the Observation ID (ObsID)
  • HIPE expects the data in the form of a Pool, so HSA data must be imported into HIPE
  • A Pool is like a database, with observations organised as an Observation Context, containing links to all data, calibration and supplementary files

There are three main ways to import data from the HSA into HIPE:

  1. Directly from the HIPE command line (SDRG Section 4.1.2) using myobs=getObservation(obsID, useHsa=True), or to directly save the data to disk myobs=getObservation(obsID, useHsa=True, save=True).
  2. Download a tar file by selecting ''Retrieve'' in the HSA GUI, unpack it, and then ''index'' it in HIPE using myObs=getObservation(path="/path/to/dir").
  3. Import directly into HIPE selecting ''Send to HIPE'' in the HSA GUI. To save this observation from HIPE to a pool on your local disk use, saveObservation(myobs, poolName="myPool", saveCalTree=True).

Once the data are saved (and indexed) on your hard disk, the Observation Context can be read back into HIPE using, myobs=getObservation(ObsID).

2.1.2. Looking at your Data

This topic is covered in general in SDRG Section 4.2

For Photometer modes see SDRG Section 6.1, and for the Spectrometer see SDRG Section 7.2

Once the data are in HIPE, the Observation Context will be visible in the HIPE variables window:

  • Double click to open the ''Observation Viewer'' (or right click > Open With>Observation Viewer)

  • Data are available at different levels of processing (SDRG Figure 4.11):

    • Level 0: Raw data

    • Level 0.5: Basic processed voltage timeline data

    • Level 1 (Photometer): Flux calibrated timelines in Jy/beam

    • Level 1 (Spectrometer): Interferograms in V

    • Level 2 (Photometer): Flux calibrated maps for signal, error and coverage in Jy/beam

    • Level 2 (Photometer): Flux calibrated maps for signal, error and coverage in MJy/sr

    • Level 2 (Photometer): For SSO observations, point source maps in the moving frame for signal, error and coverage in Jy/beam

    • Level 2 (Photometer): Destriper Diagnotic Products

    • Level 2 (Spectrometer): Extended calibrated spectrum in W/m2/Hz/sr and point source calibrated spectrum in Jy; or 2D list of spectra and spectral cube in W/m2/Hz/sr

    • Other ancillary files are also available (see SDRG Section 4.2.5)

  • Data products can be viewed by clicking on the small “+” next to the folders to expand the tree in the same way as a file system. Clicking on one level opens it in an appropriate viewer (right click to choose which). Double clicking opens the viewer in its own tab. The main viewers are:

    • Context Viewer – shows the entire context as a tree of products

    • Dataset Viewer – shows data as a table array

    • TablePlotter – allows one table of data to be plotted

    • OverPlotter – allows different tables to be opened in the same plotter

    • Image Viewer – displays a 2D image

    • SDI/SDS Explorer – shows interferograms/spectra from all Spectrometer detectors