Query : 2008A&A...480..671P

2008A&A...480..671P - Astronomy and Astrophysics, volume 480, 671-676 (2008/3-4)

Heavy absorption and soft X-ray emission lines in the XMM-Newton spectrum of the type 2 radio-loud quasar 3C 234.


Abstract (from CDS):

We report results on a 40ks XMM-Newton observation of the type 2 quasar 3C 234. Optical spectropolarimetric data have demonstrated the presence of a hidden broad-line region in this powerful (MV≤-24.2 after reddening and starlight correction) narrow-line FRII radio galaxy. Our analysis is aimed at investigating the X-ray spectral properties of this peculiar source that have remained poorly known so far. We analyze the 0.5-10keV spectroscopic data collected by the EPIC cameras in 2006. The X-ray spectrum of this radio-loud quasar is typical of a local Compton-thin Seyfert 2 galaxy. It exhibits strong absorption (NH∼3.5x1023cm–2) and a narrow, neutral Fe Kα emission line with an equivalent width of ≃140±40eV. Our observation also reveals that the soft portion of the spectrum is characterized by strong emission lines with a very low level of scattered primary continuum. A possible explanation of these features in terms of thermal emission from a two-temperature, collisionally ionized plasma emission seems to be unlikely due to the high luminosity estimated for this component (L0.5–2∼6x1042erg/s). It is likely that most of the soft X-ray emission originates from a photoionized plasma as commonly observed in obscured, radio-quiet Seyfert-like AGNs. This X-ray observation has definitively confirmed the presence of a hidden quasar in 3C 234. The line-rich spectrum and the steepness of the hard X-ray continuum (Γ≃1.7) found in this source weaken the hypothesis that the bulk of the X-ray emission in radio-loud AGNs with high-excitation optical lines arises from jet non-thermal emission.

Abstract Copyright:

Journal keyword(s): galaxies: active - galaxies: nuclei - quasars: individual: 3C 234 - X-rays: galaxies

Simbad objects: 4

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Number of rows : 4
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
1 M 77 Sy2 02 42 40.7091669408 -00 00 47.859690204 9.70 9.61 8.87 10.1 9.9 ~ 4527 2
2 3C 234.0 Sy1 10 01 49.5227371368 +28 47 08.943487440   18.21 17.27     ~ 423 1
3 NAME Circinus Galaxy Sy2 14 13 09.906 -65 20 20.47   10.89 9.84 10.6 10.0 ~ 1185 2
4 LEDA 68751 Sy1 22 23 49.5400938871 -02 06 12.859452336   16.93 15.77 16.02   ~ 478 2

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