The latter is the least well known of the four and was recently the object of an international observation campaign which was able to establish its main physical characteristics. (sciencedaily.com)
Skrutskie was principal investigator of the Two - Micron All - Sky Survey (2MASS), a ground - based observation campaign taken in shorter (warmer) infrared wavelengths than those WISE will probe. (scientificamerican.com)
During its high resolution test observation campaign in October 2014, ALMA imaged the monstrous galaxy SDP.81, located 11.7 billion light - years away from the Earth in the constellation Hydra. (alma-telescope.jp)