Details

Autor(en) / Beteiligte

• Ostorero, L.
• Moderski, R.
• Stawarz, Ł.
• Begelman, M.C.
• Diaferio, A.
• Kowalska, I.
• Kataoka, J.
• Wagner, S.J.

Titel

Modelling the broad-band spectra of X-ray emitting GPS galaxies

Ist Teil von

• Astronomische Nachrichten, 2009-02, Vol.330 (2-3), p.275-278

Ort / Verlag

Berlin: WILEY-VCH Verlag

Erscheinungsjahr

2009

Quelle

Wiley Online Library All Journals

Beschreibungen/Notizen

• The study of the broad‐band emission of GHz‐Peaked‐Spectrum (GPS) radio galaxies is a powerful tool to investigate the physical processes taking place in the central, kpc‐sized region of their active hosts, where the jets propagate and the lobes expand, interacting with the surrounding interstellar medium (ISM). We recently developed a new dynamical‐radiative model to describe the evolution of the GPS phenomenon (Stawarz et al. 2008): as the relativistic jets propagate through the ISM, gradually engulfing narrow‐line emitting gas clouds along their way, the electron population of the expanding lobes evolves, emitting synchrotron light, as well as inverse‐Compton radiation via up‐scattering of the photon fields from the host galaxy and its active nucleus. The model, which successfully reproduces the key features of the GPS radio sources as a class, provides a description of the evolution of their spectral energy distribution (SED) with the lobes' expansion, predicting significant and complex X‐ray to γ ‐ray emission.We apply here the model to the broad‐band SED's of a sample of known, X‐ray emitting GPS galaxies, and show that (i) the free‐free absorption mechanism enables us to reproduce the radio continuum at frequencies below the turnover; (ii) the lobes' non‐thermal, inverse‐Compton emission can account for the observed X‐ray spectra, providing a viable alternative to the thermal, accretion‐dominated scenario. We also show that, in our sample, the relationship between the X‐ray and radio hydrogen column densities, NH and NHI, is suggestive of a positive correlation, which, if confirmed, would support the scenario of high‐energy emitting lobes (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)