AAS 198th Meeting, June 2001
Session 73. Radio Galaxies
Display, Thursday, June 7, 2001, 9:20am-4:00pm, Exhibit Hall

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[73.08] Chandra and RXTE observations of the Cyg A nucleus

Y. Terashima (ISAS Japan and Univ. of Maryland), A.S. Wilson (Univ. of Maryland), K. Arnaud (NASA/GSFC and Univ. of Maryland), A.J. Young, D.A. Smith (Univ. of Maryland), P.L. Shopbell (Caltech)

We present results from almost simultaneous Chandra and RXTE observations of the active nucleus of the powerful radio galaxy Cyg A. Cyg A is surrounded by hot gas associated with the cluster of galaxies, and Chandra's high spatial resolution has allowed us to separate cleanly the X-ray emissions of the nucleus, the radio source and the cluster for the first time. We used the RXTE spectra, which includes both the cluster and the AGN emission, to constrain the spectral shape at high energies. The X-ray spectrum of the nucleus may be described by a combination of a power law (\Gamma~.6) absorbed by N\rm H~\times1023 cm-2 (which dominates the X-rays above 3 keV), a less absorbed power law (\Gamma~) seen below 3 keV, and an Fe K emission line at 6.4 keV in the source rest frame. The Chandra image in the 0.5--2 keV band is elongated and double peaked with a separation of 2.5 arcsec, while above 2 keV the Chandra image is compact. The direction of the elongation is similar to the jet axis and the bi-cone structure seen in polarized optical light. The X-ray and [OIII]\lambda5007 morphologies are very similar. These spatial correlations and the spectral shape of the soft component suggest that the extended emission may be an X-ray ionization cone which is photoionized by radiation from the nucleus. These observations provide additional evidence for the presence of obscuring/collimating material in the vicinity of this luminous AGN. YT is supported by JSPS.


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