title: Dark Matter Velocity Spectroscopy.
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.
authors: Center for Cosmology and AstroParticle Physics (CCAPP), Ohio State University, Columbus, Ohio 43210, USA.|Department of Physics, Ohio State University, Columbus, Ohio 43210, USA.
authors: Eric G
authors: EG
authors: Speckhard
authors: Center for Cosmology and AstroParticle Physics (CCAPP), Ohio State University, Columbus, Ohio 43210, USA.|Department of Physics, Ohio State University, Columbus, Ohio 43210, USA.
authors: Kenny C Y
authors: KC
authors: Ng
authors: Center for Cosmology and AstroParticle Physics (CCAPP), Ohio State University, Columbus, Ohio 43210, USA.|Department of Physics, Ohio State University, Columbus, Ohio 43210, USA.|Department of Astronomy, Ohio State University, Columbus, Ohio 43210, USA.
authors: John F
authors: JF
authors: Beacom
authors: Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), Department of Physics, Stanford University, Stanford, California 94035, USA; and SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors: Ranjan
authors: R
authors: Laha