It's a mosaic of astronomical images from my thesis. The images were obtained with a near-infrared camera at the Steward Observatory 90" Telescope on Kitt Peak near Tucson AZ.
It's a look at some images obtained with NICMOS (the Near-Infrared Camera and Multi-Object Spectrometer), which was Shuttled up to the Hubble Space Telescope in 1997. The second column shows what the host galaxies look like when the light from the pesky nucleus has been removed. Each little box is about 10 arcseconds on a side.
It's a sample of what the NICMOS images look like when they are sent down from the telescope. The big box is 19 arcsec on a side, and the quasar is the bright object to the right of center. There is lots of processing required to remove the effects of cosmic rays, dark current from the detector, differences between the quadrants, variations in pixel-to-pixel response...but they all work out in the end.
It's a mosaic of visible-lightimages of the nearby quasar PG 1116+215 obtained from the HST archive. Shown here are the quasar (upper left); a PSF star having similar saturation level to the quasar (upper right); the PSF-subtracted quasar (lower left); and a nearby galaxy from the same WFPC2 image as the quasar. All images are shown with the same logarithmic stretch, and each image is 20 arcseconds on a side. Considerable noise from saturation, bleeding, and diffraction spikes is present in the central part of the subtracted image. Note the similarity between the subtracted image and the nearby galaxy; if at the redshift of the quasar, the nearby galaxy has a luminosity of L~1.4L*, or several times that of our Milky Way.