An estimate of the electron density in filaments of galaxies at z ~ 0.1

Amelia Fraser-McKelvie, Kevin A. Pimbblet, Jasmina S. Lazendic

Research output: Contribution to journalArticleAcademicpeer-review

12 Citations (Scopus)

Abstract

Most of the baryons in the Universe are thought to be contained within filaments of galaxies, but as yet, no single study has published the observed properties of a large sample of known filaments to determine typical physical characteristics such as temperature and electron density. This paper presents a comprehensive large-scale search conducted for X-ray emission from a population of 41 bona fide filaments of galaxies to determine their X-ray flux and electron density. The sample is generated from the filament catalogue of Pimbblet et al., which is in turn sourced from the two-degree Field Galaxy Redshift Survey (2dFGRS). Since the filaments are expected to be very faint and of very low density, we used stacked ROSAT All-Sky Survey data. We detect a net surface brightness from our sample of filaments of (1.6 ± 0.1) × 10-14ergcm-2s-1arcmin-2 in the 0.9-1.3keV energy band for 1-keV plasma, which implies an electron density of ne= (4.7 ± 0.2) × 10-4h1/2100 cm-3. Finally, we examine if a filament's membership to a supercluster leads to an enhanced electron density as reported by Kull & Böhringer. We suggest it remains unclear if supercluster membership causes such an enhancement.

Original languageEnglish
Pages (from-to)1961-1966
Number of pages6
JournalMonthly Notices of the Royal Astronomical Society
Volume415
Issue number2
DOIs
Publication statusPublished - Aug 2011
Externally publishedYes

Keywords

  • Cosmology: observations
  • Galaxies: clusters: general
  • Large-scale structure of Universe
  • X-rays: general

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