NIRWALS

The near infrared integral field spectrograph NIRWALS extends SALT’s capabilities into the near infrared, providing medium resolution spectroscopy at R = 2000-5000 over the wavelength range of 800 to 1700 nm.  Its integral field unit (IFU) is an elongated hexagonal bundle of 212 fibers, each of which subtends 1.3 arcsec on the sky, approximately matching the median site seeing.  The IFU has on-sky dimensions of 29 x 18 arcsec, ideally suited for resolving nearby galaxies.  A separate 38-fiber bundle simultaneously samples the sky.  It can be adjusted to distances ranging from 48.6 to 159.2 arcsec from the object IFU with a gimbaled jaw in the Fiber Instrument Feed (FIF) that maintains telecentricity and common field angles for the object and sky bundles.  Sky fibers are interleaved with object fibers along the 8-arcmin long spectrograph slit for optimizing sky subtraction.

More information is available from the following document.

• SALT NIR Integral Field Spectrograph: Description and Performance Predictions