Light/mass offsets in the lensing cluster Abell 3827: Evidence for collisional dark matter?

Liliya L.R. Williams, Prasenjit Saha

Research output: Contribution to journalArticlepeer-review

47 Scopus citations

Abstract

If dark matter has a non-zero self-interaction cross-section, then dark matter haloes of individual galaxies in cluster cores should experience a drag force from the ambient dark matter of the cluster, which will not affect the stellar components of galaxies, and thus will lead to a separation between the stellar and dark matter. If the cross-section is only a few decades below its current astrophysically determined upper limit, then kpc-scale separations should result. However, such separations will be observable only under very favourable conditions. Abell 3827 is a nearby late stage cluster merger with four massive central ellipticals within 20kpc of each other. The 10 strong lensing images tightly surrounding the ellipticals provide an excellent set of constraints for a free-form lens reconstruction. Our free-form mass maps show a massive dark extended clump, about 6kpc from one of the ellipticals. The robustness of this result has been tested with many reconstructions, and confirmed with experiments using synthetic lens mass distributions. Interpreted in terms of dark matter collisionality, our result yields σ/m≳ 4.510-7(t/1010yr)-2cm2g-1, where t is the merger's age.

Original languageEnglish (US)
Pages (from-to)448-460
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Volume415
Issue number1
DOIs
StatePublished - Jul 2011

Keywords

  • Astroparticle physics
  • Dark matter
  • Galaxies: clusters: individual: Abell 3827
  • Gravitational lensing: strong

Fingerprint Dive into the research topics of 'Light/mass offsets in the lensing cluster Abell 3827: Evidence for collisional dark matter?'. Together they form a unique fingerprint.

Cite this