SIMBAD references

2015ApJ...808..154R - Astrophys. J., 808, 154 (2015/August-1)

NuSTAR observations of the powerful radio galaxy Cygnus A.

REYNOLDS C.S., LOHFINK A.M., OGLE P.M., HARRISON F.A., MADSEN K.K., FABIAN A.C., WIK D.R., MADEJSKI G., BALLANTYNE D.R., BOGGS S.E., CHRISTENSEN F.E., CRAIG W.W., FUERST F., HAILEY C.J., LANZ L., MILLER J.M., SAEZ C., STERN D., WALTON D.J. and ZHANG W.

Abstract (from CDS):

We present NuSTAR observations of the powerful radio galaxy Cygnus A, focusing on the central absorbed active galactic nucleus (AGN). Cygnus A is embedded in a cool-core galaxy cluster, and hence we also examine archival XMM-Newton data to facilitate the decomposition of the spectrum into the AGN and intracluster medium components. NuSTAR gives a source-dominated spectrum of the AGN out to > 70 keV. In gross terms, the NuSTAR spectrum of the AGN has the form of a power law (Γ ∼ 1.6-1.7)) absorbed by a neutral column density of NH ∼ 1.6 x 1023/cm2. However, we also detect curvature in the hard (> 10 keV) spectrum resulting from reflection by Compton-thick matter out of our line of sight to the X-ray source. Compton reflection, possibly from the outer accretion disk or obscuring torus, is required even permitting a high-energy cut off in the continuum source; the limit on the cut-off energy is Ecut > 111 keV(90% confidence). Interestingly, the absorbed power law plus reflection model leaves residuals suggesting the absorption/emission from a fast (15,000-26,000 km/s), high column-density (NW > 3 x 1023/cm2), highly ionized ({ksi= ∼ 2500 erg/s) wind. A second, even faster ionized wind component is also suggested by these data. We show that the ionized wind likely carries a significant mass and momentum flux, and may carry sufficient kinetic energy to exercise feedback on the host galaxy. If confirmed, the simultaneous presence of a strong wind and powerful jets in Cygnus A demonstrates that feedback from radio-jets and sub-relativistic winds are not mutually exclusive phases of AGN activity but can occur simultaneously.

Abstract Copyright:

Journal keyword(s): accretion, accretion disks - galaxies: clusters: intracluster medium - galaxies: jets - X-rays: individual: Cygnus A

Simbad objects: 3

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