Herschel observations of the Centaurus cluster - the dynamics of cold gas in a cool core
Résumé
Brightest cluster galaxies (BCGs) in the cores of galaxy clusters have distinctly different properties from other low-redshift massive ellipticals. The majority of the BCGs in cool-core clusters show signs of active star formation. We present observations of NGC 4696, the BCG of the Centaurus galaxy cluster, at far-infrared (FIR) wavelengths with the Herschel space telescope. Using the PACS spectrometer, we detect the two strongest coolants of the interstellar medium, [C II] at 157.74 mum and [O I] at 63.18 mum, and in addition [N II] at 121.90 mum. The [C II] emission is extended over a region of 7 kpc with a similar spatial morphology and kinematics to the optical Halpha emission. This has the profound implication that the optical hydrogen recombination line, Halpha, the optical forbidden lines, [N II] lambda6583 Å, the soft X-ray filaments and the FIR [C II] line all have the same energy source.
Domaines
Astrophysique [astro-ph]
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