Spitzer/IRS ATLAS project source

The atlas covers the full spectrum of the extragalactic Universe and includes star-forming galaxies, obscured and unobscured active galaxies, luminous and ultra-luminous infrared galaxies, and hybrid objects.

Measured features such as the polycyclic aromatic hydrocarbons, the strength of the silicates in emission or absorption around 9.7um, rest-frame monochromatic luminosities or colours, combined with measurements derived from spectral decomposition are used to establish diagnostics that allow for classification of sources, based on their infrared properties alone. Average templates of the various classes are also derived.