Abstract
Dark matter decays or annihilations that produce linelike spectra may be smoking-gun signals. However, even such distinctive signatures can be mimicked by astrophysical or instrumental causes. We show that velocity spectroscopy—the measurement of energy shifts induced by relative motion of source and observer—can separate these three causes with minimal theoretical uncertainties. The principal obstacle has been energy resolution, but upcoming experiments will have the precision needed. As an example, we show that the imminent Astro-H mission can use Milky Way observations to separate possible causes of the 3.5-keV line. We discuss other applications.
- Received 31 July 2015
DOI:https://doi.org/10.1103/PhysRevLett.116.031301
© 2016 American Physical Society
Physics Subject Headings (PhySH)
Viewpoint
A Speed Test for Dark Matter
Published 19 January 2016
Whether mysterious high-energy photon emissions from our Galaxy come from dark matter or a more mundane source might be resolved by detecting their Doppler shifts along different lines-of-sight.
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