A Chandra study of the AGN-host interaction in NGC 5728: extended ionized emission and ~0.1c outflows on kiloparsec-scales
Anna Trindade Falcão
Astrophysicist
(HEA/SAO)
Center for Astrophysics | Harvard & Smithsonian
Website
We present the first deep 260 ks Chandra/ACIS-S imaging study of the interaction between the AGN and its host galaxy in the nearby Seyfert NGC 5728. The complex and extended X-ray emission reveals a region of soft X-rays (0.3-3 keV) stretching ~2 kpc from the central source, spatially coincident with the bicone of ionized gas observed in optical wavelengths. Harder (3-6 keV) X-ray emission is detected extended ~1.4 kpc, along the same direction. Spectral fitting of spatially resolved components suggests that a low-photoionization phase mixed with a more ionized gas component dominates the nuclear spectrum, while the extended bicone is dominated by a mix of photoionization and shocked-gas emission
We also find spectrally and spatially-resolved features in the Fe Kα complex (5.0-7.5 keV), redward and blueward of the neutral Fe line in the extended (300 pc - 1.6 kpc) ionized bicone. Fits to a suite of physically motivated models confirm a significance ≥3σ for the red wing. The significance of the blue wing may be diminished by the presence of rest frame highly ionized Fe XXV (at 6.7 keV) and Fe XXVI (at 6.9 keV) lines (1.4σ-3.7σ range in significance). These red and blue features are radially extended (~1 kpc) along the optical bicone axis. If the emission arises from redshifted and blueshifted high-velocity neutral Fe Kα, then the implied line-of-sight velocities are symmetrically ~0.1c. These velocities are about 100 times larger than those of optical [O III] outflows seen in this galaxy, potentially dominating the kinetic feedback power.
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