Astronomy with a Mid-Infrared Echelle Spectrograph

Abstract

Irshell, a mid-infrared echelle spectiograph developed through a collaboration between the University of Texas, the University of California Space Sciences Laboratory, and Hughes Aircraft, has been in regular use for astronomical observations for about five years. It is optimized for high spectral resolution (R~l0,000) observations of narrow spectral regions (Δλ/λ ~ 1/300) and compact sources (a few arcsec), and is sensitive in the 5–25μm region. A wide variety of astronomical objects have been studied. Observing techniques have been developed to achieve maximum sensitivity in those observations for which Irshell is best suited and to allow observations of wide spectral regions and extended objects. We discuss the observing techniques and show some of the data obtained.