Project overview

The PPAK IFS Nearby Galaxies Survey (PINGS) is a 2-dimensional spectroscopic mosaicking of 17 nearby disk galaxies in the optical wavelength range. This project represented the first attempt to obtain continuous coverage spectra of the whole surface of a galaxy in the nearby universe using the instrumental capabilities of the PMAS/PPAK spectrograph at the Centro Astronómico Hispano-Alemán at Calar Alto, Spain. For more details on the project and related science see the Publications section.

The instrument

The PMAS/PPAK instrument is one of the world's widest integral field unit (IFU) which provides a semi-contiguous regular sampling of extended astronomical objects (~ 1.25 arcmin). The Postdam Multi-Aperture Spectrophotometer (PMAS) is a dedicated integral field spectrophotometer optimised to cover the optical wavelength regime of 0.35-1 microns. It is based on a lens array-fiber bundle principle of operation. The PMAS fiber PAcK (PPAK) is a retrofitted bare fiber bundle IFU which expands the FOV of PMAS to an hexagonal area with a footprint of 65 x 74 arcsec. The PPAK unit features a central hexagonal bundle with 331 densely packed optical fibers to sample an astronomical object at 2.7 arcsec per fiber. A single large PPAK fiber collects more light even with a 3.5 telescope than a single spatial element of an IFU mounted in a 8m-class telescope. PPAK is ideally suited to study extended astronomical objects with low surface brightness, where light collecting power is more important than detailed spatial resolution.

Left: PMAS-PPAK mounted at 3.5m telescope at CAHA.
Right: PPAK-IFU diagram, showing the hexagonal field of view of the instrument.