Extended X-ray emission from the BL Lac object PKS 0521-365

M.J. Hardcastle, D.M. Worrall, M. Birkinshaw

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9 Citations (Scopus)
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Models that seek to unify BL Lacs and low-power radio galaxies predict that the two types of object should show similar isotropically emitted X-ray emission. Testing this is usually limited by difficulties in separating strong X-ray emission from a BL Lac nucleus and surrounding low-surface brightness emission. In this paper we report ROSAT HRI observations of the z = 0.055 BL Lac object PKS 0521−365.We are able to separate a luminous extended X-ray component from the bright nucleus. Using a new radio map, we show that it is unlikely that the extended emission is due to inverse- Compton scattering of photons from the active nucleus, and instead interpret it as thermal emission from dense, rapidly cooling gas. This is a more extreme environment than is found in typical FRI radio galaxies, and may pose a problem for unified models.
Original languageEnglish
Pages (from-to)246-252
JournalMonthly Notices of the Royal Astronomical Society
Issue number2
Publication statusPublished - 1999


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