7. Low Resolution Spectral Mapping at 5-14 microns with the IRS

In this chapter, we illustrate use of the Infrared Spectrograph (IRS) to obtain a low-resolution spectral map of an extended target. We will utilize both orders of the IRS Short-Low (SL) module. This detailed example of an IRS Spectral Mapping Mode observation expands the basic example given in the IRS chapter of the Spitzer Observer's Manual (SOM). The target is the Ring Nebula, a well-known planetary nebula located at RA = 18:53:35.16, DEC = +33:01:43.2 (J2000) (Galactic latitude $\sim$+55). The goal of this observation is to compare spectra of opposite sides of the Ring Nebula in order to look for differences in spectral features and continuum shapes. Some of the information and steps used in preparing this observation are substantially similar (or identical) to those described in Chapter 6 for an IRS Staring Mode observation. We describe those steps only briefly (or not at all) in this chapter; instead, we concentrate on material specific to the IRS Spectral Mapping Mode.

Note that this example is intended to demonstrate the operational modes of the IRS and how to propose for IRS observations, but not to present a rigorous scientific case for the observations described herein.