The nongravitational interactions of dark matter in colliding galaxy clusters

David Harvey*, Richard Massey, Thomas Kitching, Andy Taylor, Eric Tittley

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Collisions between galaxy clusters provide a test of the nongravitational forces acting on dark matter. Dark matter’s lack of deceleration in the “bullet cluster” collision constrained its self-interaction cross section σDM/m < 1.25 square centimeters per gram (cm2/g) [68% confidence limit (CL)] (σDM, self-interaction cross section; m, unit mass of dark matter) for long-ranged forces. Using the Chandra and Hubble Space Telescopes, we have now observed 72 collisions, including both major and minor mergers. Combining these measurements statistically, we detect the existence of dark mass at 7.6σ significance. The position of the dark mass has remained closely aligned within 5.8 ± 8.2 kiloparsecs of associated stars, implying a self-interaction cross section σDM/m < 0.47 cm2/g (95% CL) and disfavoring some proposed extensions to the standard model.

Original languageEnglish
Pages (from-to)1462-1465
Number of pages4
JournalScience
Volume347
Issue number6229
DOIs
Publication statusPublished - 27 Mar 2015

Keywords

  • INTERACTION CROSS-SECTION
  • SUBSTRUCTURE
  • SIMULATIONS
  • CONSTRAINTS
  • 1E-0657-56
  • EXISTENCE
  • SCALE
  • HALOS
  • MILKY

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