A recent observation by the Long-Range Reconnaissance Imager (LORRI) mounted on NASA’s New Horizons yielded the most accurate measurement of the cosmic optical background (COB). The reported COB intensity is $11.16\pm 1.35\mathrm{nW}/{\mathrm{m}}^2/\mathrm{sr}$ at a pivot wavelength ${\lambda }_{\mathrm{piv}}=0.608\mathrm{\mu }\mathrm{m}$ observed in the range $0.4\mathrm{\mu }\mathrm{m}\lesssim \lambda \lesssim 0.9\mathrm{\mu }\mathrm{m}$. After subtracting the measured intensity from the deep Hubble Space Telescope count, diffused galactic light, and scattered light from bright star foregrounds, an anomalous intensity of $2.99\pm 2.03\mathrm{nW}/{\mathrm{m}}^2/\mathrm{sr}$ has been found. We consider radiatively decaying sterile neutrinos of keV mass scale as dark matter candidates that could contribute to this anomalous reported intensity. Using this, we derive upper bounds on the sterile-to-sterile transition magnetic moment. We find that sterile neutrinos with mass of $\mathcal{O}(\mathrm{keV})$ scale take values of the transition magnetic moment in the range $3\times {10}^{-13}{\mathrm{eV}}^{-1}–{10}^{-9}{\mathrm{eV}}^{-1}$ to explain the anomalous intensity of $2.99\pm 2.03\mathrm{nW}/{\mathrm{m}}^2/\mathrm{sr}$.

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• Cosmology
• Dark matter
• Electromagnetic radiation astronomy
• Optical, UV, & IR astronomy
• Sterile neutrinos