IRS Data Reduction Recipes

Welcome to the IRS Data Reduction Recipes page.

This website contains step-by-step recipes for reducing data taken by the Infrared Spectrograph (IRS) on board the Spitzer Space Telescope.

In addition, we recommend that you consult the following resources:

1. The IRS Data Handbook
2. The IRS Data Features/Caveats Page
3. The Spitzer FAQ
4. The "Basic Data Reduction Steps" section near the bottom of the IRS Data Analysis Page
5. The SPICE Page
6. The SMART page
7. The CUBISM page

IRS Recipes:

Retrieving your data	This link provides both general information and specific examples on how to retrieve data, whether public or proprietary, from the Spitzer archives.
Creating spectral cubes: M51	This recipe shows you how to use CUBISM to analyze an IRS LL map of the extended galaxy M51.
Using dark_settle to mitigate time-dependent dark current in LH IRS spectra	The primary goal of this recipe is to show you how to recognize the effects of time-dependent dark current in your Long-High IRS data, and how to correct these effects using the SSC-provided IDL software dark_settle. In addition, this recipe provides an introduction to batch mode in SPICE, for easy extraction of 1D spectra from multiple BCDs using identical parameters.
Using SPICE from the command-line	In this recipe, we demonstrate how to use the command-line version of SPICE to extract a Spitzer IRS Short-Low spectrum of Herbig-Haro 46/47.
Fringe Removal: Herbig-Haro 46/47	This link demonstrates how to use IRSFRINGE to remove fringing from IRS-LH staring-mode observations of the Herbig-Haro object HH 46/47. These basic steps are applicable to any point-source data obtained with IRS in staring mode. IRSFRINGE was developed and tested to run under IDL 5.6, and no guarantees are made for other IDL versions.
Point Source Extraction: NGC 4579	NGC4579 is an extragalactic source which was observed as part of the SINGS Legacy program. The source was mapped out using both the low and high resolution modules of the IRS. In this recipe we outline the steps required to go from the zip file you get from the Spitzer data archive to a basic SL and LL spectrum using the spectral extraction tool called SPICE. The illustration here is for only one position in the spectral map but can be used for any observation performed in the staring mode or spectral mapping mode.
Point Source Extraction: Herbig-Haro 46/47	This is a demonstration of using SPICE to extract a spectrum from IRS SL2 data for the object Herbig-Haro 46/47. We outline the basic steps for using SPICE as a generic example for handling any point source data obtained with Spitzer IRS-Staring Mode. The steps are analogous to those outlined here. This specific example involves an extraction from the SL2 module, but it is generally applicable to all of the IRS modules. This demonstrates only a point source extraction; SPICE is currently capable of extracting spectra for extended sources. For a discussion, see the IRS Extended Source calibration page on our website.
Moving Target: Comet Schwassmann-Wachmann-1	This demonstration uses SPICE to extract a spectrum from IRS data of the Comet Schwassmann-Wachmann-1. We describe the steps required to background-subtract your data and use the SPICE tool to perform a custom extraction of your target's spectrum. Background subtraction is particularly important for targets on a high background, such as that found in the ecliptic plane. Similarly for a moving target such as a comet, a custom extraction, rather than the standard pipeline product, may be important to separate the effects of nucleus and coma, and to otherwise correctly extract a slightly extended object, or one with an unusual morphology. This demonstration then, serves as a generic example for handling moving target data obtained with Spitzer IRS-Staring Mode. This specific example involves an extraction from the LL2 module, but it is generally applicable to all of the IRS modules.
Ultradeep IRS Spectroscopy	In this recipe, we demonstrate the data reduction strategies used for ultradeep IRS spectroscopy. This page follows the IRS Best Practices memo for the same observation, but we now include optimal extraction in SPICE which was not previously available. The ultradeep proof of concept data (PID=252) included observations in SL1, LL2, and LL1. We use the LL1 data here. The target was a z=2.69 ULIRG. A total of 12 hours on-source integration was performed, using mapping-mode to place the target at 6 positions along the slit.
SMART extraction: SL	HD105 is a G0V star that was observed as part of the FEPS Legacy program. The source was observed using both the low and the high spectral resolution modules of the IRS. In this page we outline the steps required to go from the zip file you get from the Spitzer data archive to a basic spectrum using SMART.
SMART extraction: SH	ksi Dra is a K2 giant star, which is observed about once a month, as part of routine calibration observations. It is generally observed in the LL, SH, and LH modules. Here we concentrate on SH. In this page we outline the steps required to go from the zip file you get from the Spitzer data archive to a basic spectrum using SMART.
Synthetic Photometry	This link provides information (and IDL software) on how to determine the expected flux recorded by any of Spitzer's imagers (including the IRS Peak-Up imagers), given an input spectrum.

Return to the Data Analysis Cookbook.