Recent high-resolution measurements suggest that the soft X-ray spectrum of obscured radio galaxies exhibits signatures of photoionized gas (e.g. 3C 445 and 3C 33) similar to those observed in radio-quiet obscured active galactic nuclei. While signatures of warm absorbing gas covering a wide range of temperature and ionization states have been detected in about one-half of the population of nearby type 1 Seyfert galaxies, no traces of warm absorber gas have been reported to date in the high-resolution spectra of broad-line radio galaxies (BLRG). We present here the first detection of a soft X-ray warm absorber in the powerful Fanaroff-Riley type II BLRG 3C 382 using the Reflection Grating Spectrometer on-board XMM-Newton. The absorption gas appears to be highly ionized, with column density of the order of 10^22 cm-2, ionization parameter logξ > 2 ergcms-1 and outflow velocities of the order of 103 kms-1. The absorption lines may come from regions located outside the torus, however, at distances less than 60 pc. This result may indicate that a plasma ejected at velocities near the speed of light and a photoionized gas with slower outflow velocities can coexist in the same source beyond the broad-line regions.
Torresi E., Grandi P., Longinotti A. L., Guainazzi M., Palumbo G. G. C., Tombesi F., et al. (2010). First high-resolution detection of a warm absorber in the Broad Line Radio Galaxy 3C 382. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 401, L10-L14 [10.1111/j.1745-3933.2009.00773.x].
First high-resolution detection of a warm absorber in the Broad Line Radio Galaxy 3C 382
TORRESI, ELEONORA;PALUMBO, GIORGIO;TOMBESI, FRANCESCO;
2010
Abstract
Recent high-resolution measurements suggest that the soft X-ray spectrum of obscured radio galaxies exhibits signatures of photoionized gas (e.g. 3C 445 and 3C 33) similar to those observed in radio-quiet obscured active galactic nuclei. While signatures of warm absorbing gas covering a wide range of temperature and ionization states have been detected in about one-half of the population of nearby type 1 Seyfert galaxies, no traces of warm absorber gas have been reported to date in the high-resolution spectra of broad-line radio galaxies (BLRG). We present here the first detection of a soft X-ray warm absorber in the powerful Fanaroff-Riley type II BLRG 3C 382 using the Reflection Grating Spectrometer on-board XMM-Newton. The absorption gas appears to be highly ionized, with column density of the order of 10^22 cm-2, ionization parameter logξ > 2 ergcms-1 and outflow velocities of the order of 103 kms-1. The absorption lines may come from regions located outside the torus, however, at distances less than 60 pc. This result may indicate that a plasma ejected at velocities near the speed of light and a photoionized gas with slower outflow velocities can coexist in the same source beyond the broad-line regions.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.