6. High Resolution Staring Mode Observations at 10-37 microns with the IRS

In this chapter, we illustrate use of the Infrared Spectrograph (IRS) to obtain high-resolution spectra of a point source target. We will utilize the Short-High (SH) and Long-High (LH) modules of the IRS. This detailed example of an IRS Staring Mode observation expands the basic example given in the IRS chapter of the Spitzer Observer's Manual (SOM). The goal of this observation is to detect (or establish upper flux limits for) polycyclic aromatic hydrocarbon (PAH) lines at $13.1$ and $24.5 \; \mu {\rm m}$ (redshifted from $11.3$ and $21.2 \; \mu {\rm m}$) in the well-known quasar 3C 273. Additional dust and atomic spectral features in the $20-30 \; \mu {\rm m}$ range (e.g., Moutou et al. 1996, A&A, 310, 297) could also be investigated with these IRS data. 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.