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I will talk about our new observations of the cosmic ultraviolet background (CUVB) at high Galactic latitudes, made using the Alice UV spectrograph on board the New Horizons spacecraft at a distance of 57 AU from the Sun. We obtained the first spectrum of the CUVB between 912 -- 1800 Å. We found two components of the diffuse background: one due to starlight scattered from interstellar I dust and an isotropic component, represented by an offset at zero-reddening. This offset is greater than would be expected from known sources with a level of 220 photon units at 1000 Å and 260 photon units at 1500 Å. (4.4 nW m-2 sr-1 at 1000 Å and 5.3 nW m-2 sr-1 at 1500 Å. The former is the first firm detection of the offset in the range 912 -- 1100 Å while the latter result confirms previous results from GALEX, showing that there is little emission from the Solar System from 1400 -- 1800 Å. About half of the offset may be explained by known sources (the integrated light of unresolved galaxies, unresolved stars, emission from ionized gas, and two-photon emission from warm hydrogen in the halo). The remainder (about half of the total) is unexplained with the strongest candidate being axion decay. An important corollary of our observations is that there is no emission from the Solar System between 1300 and 1800 Å, providing an open window into the Universe.
Jayant Murthy obtained his PhD from the Johns Hopkins University in 1987. He was a National Research Council Fellow at NASA/GSFC for two years and then a Research Professor at Johns Hopkins. He later joined the Indian Institute of Astrophysics where he is now a Honorary Professor. Murthy works on the interstellar medium (dust and gas between stars) and also builds instruments for space flight. The latest is a proposal to fly on the Chinese Space Station as part of a United Nations program.