Related by context. Frequent words. (Click for all words.) 66 spectroscopic 64 X ray emission 64 XMM Newton 61 spectra 61 interferometry 61 quasar 60 quasars 59 supernova remnant 59 aerosol particles 59 distant galaxies 58 FRET 58 gamma rays 58 elliptical galaxies 58 infrared wavelengths 58 cosmic microwave background 58 gravitational lensing 57 globular cluster 57 spectral 57 nebulae 57 redshift 57 galaxy cluster 57 reflectance 57 auroral 56 gamma ray 56 neutrino 56 Raman spectroscopy 56 supernova explosions 56 supernovae 56 photometric 56 galaxy clusters 55 GRBs 55 infrared radiation 55 muons 55 extrasolar planets 55 brown dwarf 55 interstellar dust 55 gravitational waves 55 galaxies 55 laser pulses 55 muon 55 nebula 54 gamma ray burst 54 Orion Nebula 54 quark gluon plasma 54 ejecta 54 HD #b [002] 54 anisotropy 54 Spitzer Space Telescope 54 distant galaxy 54 spectroscopy 54 photons 54 infrared 54 gravitational wave 54 pulsars 54 wavelengths 53 water vapor 53 globular clusters 53 WIMPs 53 aurora 53 interstellar medium 53 laser pulse 53 brown dwarfs 53 pulsar 53 astronomers 53 Fluorescence 53 dwarf galaxies 53 magnetar 53 neutrinos 53 cosmic rays 53 particle 53 ESO Very Large Telescope 53 fluorescence 53 photon 53 celestial object 53 spectrometry 53 spiral galaxies 52 astronomical objects 52 WMAP 52 extrasolar planet 52 dwarf galaxy 52 Andromeda Galaxy 52 astrophysicists 52 cosmic ray 52 optical telescopes 52 diffraction 52 positrons 52 Spectrometer 52 isotopic 52 magnetic fields 52 Andromeda galaxy 52 planets orbiting 52 starlight 51 comet nucleus 51 NASA Chandra 51 planet orbiting 51 X ray Observatory 51 neutron stars 51 deuterium 51 gamma ray bursts 51 vibrational 51 hydroxyl