Extended X-ray Emission in Compton Thick AGN with Deep Chandra Observations

We present the spatial analysis of five Compton thick (CT) active galactic nuclei (AGNs), including MKN 573, NGC 1386, NGC 3393, NGC 5643, and NGC 7212, for which high resolution Chandra observations are available. For each source, we find hard X-ray emission (>3 keV) extending to ~kpc scales along the ionization cone, and for some sources, in the cross-cone region. This collection represents the first, high-signal sample of CT AGN with extended hard X-ray emission for which we can begin to build a more complete picture of this new population of AGN. We investigate the energy dependence of the extended X-ray emission, including possible dependencies on host galaxy and AGN properties, and find a correlation between the excess emission and obscuration, suggesting a connection between the nuclear obscuring material and the galactic molecular clouds. Furthermore, we find that the soft X-ray emission extends farther than the hard X-rays along the ionization cone, which may be explained by a galactocentric radial dependence on the density of molecular clouds due to the orientation of the ionization cone with respect to the galactic disk. These results are consistent with other CT AGN with observed extended hard X-ray emission (e.g., ESO 428-G014 and the Ma et al. 2020 CT AGN sample), further demonstrating the ubiquity of extended hard X-ray emission in CT AGN.Comment: 29 pages, 22 figures, 7 tables, Accepted for publication in Ap

Powerful Yet Lonely: Is 3C 297 a High-redshift Fossil Group?

The environment of the high-redshift (z = 1.408), powerful radio-loud galaxy 3C 297 has several distinctive features of a galaxy cluster. Among them, a characteristic halo of hot gas revealed by Chandra X-ray observations. In addition, a radio map obtained with the Very Large Array shows a bright hotspot in the northwestern direction, created by the interaction of the active galactic nucleus (AGN) jet arising from 3C 297 with its environment. In the X-ray images, emission cospatial with the northwestern radio lobe is detected, and peaks at the position of the radio hotspot. The extended, complex X-ray emission observed with our new Chandra data is largely unrelated to its radio structure. Despite having attributes of a galaxy cluster, no companion galaxies have been identified from 39 new spectra of neighboring targets of 3C 297 obtained with the Gemini Multi-Object Spectrograph. None of the 19 galaxies for which a redshift was determined lies at the same distance as 3C 297. The optical spectral analysis of the new Gemini spectrum of 3C 297 reveals an isolated Type II radio-loud AGN. We also detected line broadening in [O ii] λ3728 with a FWHM about 1700 km s−1 and possible line shifts of up to 500–600 km s−1. We postulate that the host galaxy of 3C 297 is a fossil group, in which most of the stellar mass has merged into a single object, leaving behind an X-ray halo