Detection of optical coronal emission from 106-K gas in the core of the Centaurus cluster

R. E.A. Canning, A. C. Fabian, R. M. Johnstone, J. S. Sanders, C. S. Crawford, N. A. Hatch, G. J. Ferland

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


We report a detection (3.5 × 1037± 5.6 × 1036 ergs-1) of the optical coronal emission line [Fex]λ6374 and upper limits of four other coronal lines using high-resolution VIMOS spectra centred on NGC 4696, the brightest cluster galaxy in the Centaurus cluster. Emission from these lines is indicative of gas at temperatures between 1 × 106-5 × 106K, so traces the interstellar gas in NGC 4696. The rate of cooling derived from the upper limits is consistent with the cooling rate from X-ray observations (∼10 Myr-1); however, we detect twice the luminosity expected for [Fex]λ6374 emission, at 106 K, our lowest temperature probe. We suggest this emission is due to the gas being heated rather than cooling out of the intracluster medium. We detect no coronal lines from [Caxv], which are expected from the 5 × 106K gas seen near the centre in X-rays with Chandra. Calcium is, however, likely to be depleted from the gas phase on to dust grains in the central regions of NGC 4696.

Original languageEnglish
Pages (from-to)411-421
Number of pages11
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
StatePublished - Feb 2011


  • Galaxies: clusters: individual: Centaurus
  • Galaxies: clusters: intracluster medium

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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