We investigate the X-ray spectral properties of 3C 33 by analyzing all the observations available in the Chandra and XMM-Newton archives. In this paper we present a complete X-ray analysis of the nuclear emission of this narrow-line radio galaxy. The broad-band spectrum of 3C 33 is complex. Its hard part resembles that of Seyfert 2 galaxies, which have a heavily obscured nuclear continuum (NH ~ 10^23 cm-2) and a prominent Fe Kα line. This represents the nuclear radiation observed directly in transmission through a cold circumnuclear gas. On the other hand an unabsorbed continuum plus emission lines seem to reproduce the soft part of the spectrum (0.5-2 keV) well, suggesting that the jet does not contribute significantly to the X-ray emission. We discuss the possible collisional or photoionized origin of the gas that emits the soft X-ray lines. Our results, supported by those from optical spectroscopy, favor the photoionization scenario.
Torresi E., Grandi P., Guainazzi M., Palumbo G. G. C., Ponti G., Bianchi S. (2009). 3C 33: another case of photoionized soft X-ray emission in radio galaxies. ASTRONOMY & ASTROPHYSICS, 498, 61-66 [10.1051/0004-6361/200810944].
3C 33: another case of photoionized soft X-ray emission in radio galaxies
TORRESI, ELEONORA;PALUMBO, GIORGIO;
2009
Abstract
We investigate the X-ray spectral properties of 3C 33 by analyzing all the observations available in the Chandra and XMM-Newton archives. In this paper we present a complete X-ray analysis of the nuclear emission of this narrow-line radio galaxy. The broad-band spectrum of 3C 33 is complex. Its hard part resembles that of Seyfert 2 galaxies, which have a heavily obscured nuclear continuum (NH ~ 10^23 cm-2) and a prominent Fe Kα line. This represents the nuclear radiation observed directly in transmission through a cold circumnuclear gas. On the other hand an unabsorbed continuum plus emission lines seem to reproduce the soft part of the spectrum (0.5-2 keV) well, suggesting that the jet does not contribute significantly to the X-ray emission. We discuss the possible collisional or photoionized origin of the gas that emits the soft X-ray lines. Our results, supported by those from optical spectroscopy, favor the photoionization scenario.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
