Signatures of Feedback in the Spectacular Extended Emission Region of NGC 5972
/ Authors
T. Harvey, W. Maksym, W. Keel, M. Koss, V. Bennert, S. Chojnowski, E. Treister, C. Finlez, C. Lintott, A. Moiseev
and 3 more authors
/ Abstract
We present Chandra X-ray Observatory observations and Space Telescope Imaging Spectrograph spectra of NGC 5972, one of the 19 ”Voorwerpjes” galaxies. This galaxy contains an Extended Emission Line Region (EELR) and an arc-second scale nuclear bubble. NGC 5972 is a faded AGN, with EELR luminosity suggesting a 2.1 dex decrease in Lbol in the last ∼5 × 104 yr. We investigate the role of AGN feedback in exciting the EELR and bubble given the long-term variability and potential accretion state changes. We detect broad-band (0.3-8keV) X-ray emission in the near-nuclear regions, coincident with the [O iii] bubble, as well as diffuse soft X-ray emission coincident with the EELR. The soft nuclear (0.5-1.5 keV) emission is spatially extended and the spectra are consistent with two APEC thermal populations (∼0.80 ∼0.10 keV). We find a bubble age >2.2 Myr, suggesting formation before the current variability. We find evidence for efficient feedback with P$_{\textrm {kin}}/L_{\textrm {bol}}\sim 0.8\%$, which may be overestimated given the recent Lbol variation. [O iii] kinematics show a 300 km s−1 high-ionization velocity consistent with disturbed rotation or potentially the LOS component of a ∼780 km s−1 thermal X-ray outflow capable of driving strong shocks to photoionize the precursor material. We explore possibilities to explain the overall jet, radio lobe and EELR misalignment including evidence for a double SMBH which could support a complex misaligned system.
Journal: Monthly Notices of the Royal Astronomical Society