Evidence for a circum-nuclear and ionised absorber in the X-ray obscured BroadLine Radio Galaxy 3C 445

Here we present the results of a Suzaku observation of the Broad Line Radio Galaxy 3C 445. We confirm the results obtained with the previous X-ray observations which unveiled the presence of several soft X-ray emission lines and an overall X-ray emission which strongly resembles a typical Seyfert 2 despite of the optical classification as an unobscured AGN. The broad band spectrum allowed us to measure for the first time the amount of reflection (R~0.9) which together with the relatively strong neutral Fe Kalpha emission line (EW ~ 100 eV) strongly supports a scenario where a Compton-thick mirror is present. The primary X-ray continuum is strongly obscured by an absorber with a column density of NH =2-3 x10^{23} cm^{-2}. Two possible scenarios are proposed for the absorber: a neutral partial covering or a mildly ionised absorber with an ionisation parameter log\xi ~ 1.0 erg cm s^{-1}. A comparison with the past and more recent X-ray observations of 3C 445 performed with XMM-Newton and Chandra is presented, which provided tentative evidence that the ionised and outflowing absorber varied. We argue that the absorber is probably associated with an equatorial disk-wind located within the parsec scale molecular torus.Comment: Accepted by MNRAS; 13 pages, 6 figures, 4 table

Discovery of ultra-fast outflows in a sample of Broad Line Radio Galaxies observed with Suzaku

We present the results of a uniform and systematic search for blue-shifted Fe K absorption lines in the X-ray spectra of five bright Broad-Line Radio Galaxies (BLRGs) observed with Suzaku. We detect, for the first time at X-rays in radio-loud AGN, several absorption lines at energies greater than 7 keV in three out of five sources, namely 3C 111, 3C 120 and 3C 390.3. The lines are detected with high significance according to both the F-test and extensive Monte Carlo simulations. Their likely interpretation as blue-shifted Fe XXV and Fe XXVI K-shell resonance lines implies an origin from highly ionized gas outflowing with mildly relativistic velocities, in the range 0.04-0.15c. A fit with specific photo-ionization models gives ionization parameters in the range log_xi~4-5.6 and column densities of N_H~10^22-10^23 cm^-2. These characteristics are very similar to those of the Ultra-Fast Outflows (UFOs) previously observed in radio-quiet AGN. Their estimated location within ~0.01-0.3pc from the central super-massive black hole suggests a likely origin related with accretion disk winds/outflows. Depending on the absorber covering fraction, the mass outflow rate of these UFOs can be comparable to the accretion rate and their kinetic power can correspond to a significant fraction of the bolometric luminosity and is comparable to their typical jet power. Therefore, these UFOs can play a significant role in the expected feedback from the AGN on the surrounding environment and can give us further clues on the relation between the accretion disk and the formation of winds/jets in both radio-quiet and radio-loud AGN.Comment: Accepted for publication in The Astrophysical Journal; corrected reference

Chandra High Resolution Spectroscopy of the Circumnuclear Matter in the Broad Line Radio Galaxy, 3C 445

We present evidence for X-ray line emitting and absorbing gas in the nucleus of the Broad-Line Radio Galaxy (BLRG), 3C445. A 200 ks Chandra LETG observation of 3C 445 reveals the presence of several highly ionized emission lines in the soft X-ray spectrum, primarily from the He and H-like ions of O, Ne, Mg and Si. Radiative recombination emission is detected from O VII and O VIII, indicating that the emitting gas is photoionized. The He-like emission appears to be resolved into forbidden and intercombination line components, which implies a high density of greater than 10(sup 10) cm(sup -3), while the lines are velocity broadened with a mean width of 2600 km s(sup -1). The density and widths of the ionized lines indicate an origin of the gas on sub-parsec scales in the Broad Line Region (BLR). The X-ray continuum of 3C 445 is heavily obscured by a photoionized absorber of column density N(sub H) = 2 x 10(sup 23) cm(sup -2) and ionization parameter log xi = 1.4 erg cm s(sup -1). However the view of the X-ray line emission is unobscured, which requires the absorber to be located at radii well within any parsec scale molecular torus. Instead we suggest that the X-ray absorber in 3C 445 may be associated with an outflowing, but clumpy accretion disk wind, with an observed outflow velocity of approximately 10000 km s(sup -1)

The Suzaku view of highly-ionised outflows in AGN: II -- Location, energetics and scalings with Bolometric Luminosity

Ongoing studies with XMM-Newton have shown that powerful accretion disc winds, as revealed through highly-ionised Fe\,K-shell absorption at E>=6.7 keV, are present in a significant fraction of Active Galactic Nuclei (AGN) in the local Universe (Tombesi et al. 2010). In Gofford et al. (2013) we analysed a sample of 51 Suzaku-observed AGN and independently detected Fe K absorption in ~40% of the sample, and we measured the properties of the absorbing gas. In this work we build upon these results to consider the properties of the associated wind. On average, the fast winds (v_out>0.01c) are located ~10^{15-18} cm (typically ~10^{2-4} r_s) from their black hole, their mass outflow rates are of the order ~0.01-1 Msun/yr or ~(0.01-1) M_edd and kinetic power is constrained to ~10^{43-45} erg/s, equivalent to ~(0.1-10%) L_edd. We find a fundamental correlation between the source bolometric luminosity and the wind velocity, with v_out \propto L_bol^{\alpha} and \alpha=0.4^{+0.3}_{-0.2}$ (90% confidence), which indicates that more luminous AGN tend to harbour faster Fe K winds. The mass outflow rate M_out, kinetic power L_k and momentum flux P_out of the winds are also consequently correlated with L_bol, such that more massive and more energetic winds are present in more luminous AGN. We investigate these properties in the framework of a continuum-driven wind, showing that the observed relationships are broadly consistent with a wind being accelerated by continuum-scattering. We find that, globally, a significant fraction (~85%) of the sample can plausibly exceed the L_k/L_bol~0.5% threshold thought necessary for feedback, while 45% may also exceed the less conservative ~5% of L_bol threshold as well. This suggests that the winds may be energetically significant for AGN--host-galaxy feedback processes

Wind from the black-hole accretion disk driving a molecular outflow in an active galaxy

Powerful winds driven by active galactic nuclei (AGN) are often invoked to play a fundamental role in the evolution of both supermassive black holes (SMBHs) and their host galaxies, quenching star formation and explaining the tight SMBH-galaxy relations. Recent observations of large-scale molecular outflows in ultra-luminous infrared galaxies (ULIRGs) have provided the evidence to support these studies, as they directly trace the gas out of which stars form. Theoretical models suggest an origin of these outflows as energy-conserving flows driven by fast AGN accretion disk winds. Previous claims of a connection between large-scale molecular outflows and AGN activity in ULIRGs were incomplete because they were lacking the detection of the putative inner wind. Conversely, studies of powerful AGN accretion disk winds to date have focused only on X-ray observations of local Seyferts and a few higher redshift quasars. Here we show the clear detection of a powerful AGN accretion disk wind with a mildly relativistic velocity of 0.25c in the X-ray spectrum of IRAS F11119+3257, a nearby (z = 0.189) optically classified type 1 ULIRG hosting a powerful molecular outflow. The AGN is responsible for ~80% of the emission, with a quasar-like luminosity of L_AGN = 1.5x10^46 erg/s. The energetics of these winds are consistent with the energy-conserving mechanism, which is the basis of the quasar mode feedback in AGN lacking powerful radio jets.Comment: Revised file including the letter, methods and supplementary information. Published in the March 26th 2015 issue of Natur

Galaxy evolution: black hole feedback in the luminous quasar PDS 456

The evolution of galaxies is connected to the growth of supermassive black holes in their centers. During the quasar phase, a huge luminosity is released as matter falls onto the black hole, and radiation-driven winds can transfer most of this energy back to the host galaxy. Over five different epochs, we detected the signatures of a nearly spherical stream of highly ionized gas in the broadband x-ray spectra of the luminous quasar PDS 456. This persistent wind is expelled at relativistic speeds from the inner accretion disk, and its wide aperture suggests an effective coupling with the ambient gas. The outflow's kinetic power larger than 10(46) ergs per second is enough to provide the feedback required by models of black hole and host galaxy coevolution