The images and classifications posted here are from the paper "Mid-Infrared Galaxy Morphology from the Spitzer Survey of Stellar Structure in Galaxies (S4G): The Imprint of the de Vaucouleurs Revised Hubble-Sandage Classification System at 3.6 microns", by R. Buta, K. Sheth, M. Regan, J. Hinz, A. Gil de Paz, K. Menendez-Delmestre, J. Munoz-Mateos, M. Seibert, E. Laurikainen, H. Salo, D. Gadotti, E. Athanassoula, A. Bosma, J. Knapen, L. Ho, B. Madore, D. Elmegreen, K. Masters, S. Comeron, and M. Aravena, to be published in 2010 in the Astrophysical Journal Supplement Series
The classifications follow the de Vaucouleurs revised Hubble-Sandage classification system as described and modified in The de Vaucouleurs Atlas of Galaxies (R. J. Buta, H. G. Corwin, and S. C. Odewahn 2007, Cambridge University Press). The images are posted in the same units as those given in the de Vaucouleurs Atlas, i.e., logarithmic units of magnitudes per square arcsecond. The zero point used for all of the images was 17.69, from the Vega-based calibration. In applying the de Vaucouleurs classification system, all images were examined as if they were blue-light images. Thus, any differences between the interpretations here and those given in conventional catalogues (which are mostly blue-light types) will partly reflect the effects of bandpass. Additional terminologies (such as nr for nuclear rings and nb for nuclear bars) are described in the above ApJS paper.
Below each image is information on the directions of north and east, the angular dimensions covered by the posted area, and the surface brightness range displayed. The latter can't be considered too rigorous because each image has had its own contrast adjustment to highlight the full extent of a galaxy's morphology, from highest to lowest surface brightness.