... Black holes are thought to be the densest state of matter, and there is indirect evidence for their presence in stellar binary systems and the centers of globular clusters , galaxies , and quasars . ...
... CGRO has been operating successfully since, providing the first all-sky survey at gamma-ray energies along with exciting new observations of the sun , quasars , pulsars , supernova , black holes , and gamma-ray bursts . ...
... During ASCA's three years of operation, it has also yielded valuable data on quasars , supernova remnants , dwarf novae , pulsars , clusters of galaxies , and the mysterious X-ray background radiation that appears to come from all directions. ...
... The VLA is continually making new discoveries, including determining the composition of galaxies , passing comets , quasars , HII regions , and clusters of galaxies . ...
... plot is in galactic coordinates (the plane of our Galaxy runs horizontally through the middle) and reveals the positions of distant quasars, galaxies, stars, star clusters, nebulae, novae, and supernovae - testifying to IUE's broad range of capabilities ...