TY - JOUR
T1 - Spatially Resolved UV Diagnostics of AGN Feedback
T2 - Radiation Pressure Dominates in a Prototypical Quasar-driven Superwind
AU - Somalwar, Jean
AU - Johnson, Sean D.
AU - Stern, Jonathan
AU - Goulding, Andy D.
AU - Greene, Jenny E.
AU - Zakamska, Nadia L.
AU - Alexandroff, Rachael M.
AU - Chen, Hsiao Wen
N1 - Publisher Copyright:
© 2020. The American Astronomical Society. All rights reserved..
PY - 2020/2/20
Y1 - 2020/2/20
N2 - Galactic-scale winds driven by active galactic nuclei (AGN) are often invoked to suppress star formation in galaxy evolution models, but the mechanisms driving these outflows are hotly debated. Two key AGN feedback models are (1) radiation pressure accelerating cool gas and (2) a hot outflowing wind entraining the interstellar medium (ISM). Highly ionized emission-line diagnostics represent a powerful means of differentiating these scenarios because of their sensitivity to the expected compression of the ISM clouds by the hot wind. Here, we report the first spatially resolved UV emission spectroscopy of a prototypical (radio-quiet) quasar-driven superwind around the obscured quasar SDSS J1356+1026 at z = 0.123. We observe ratios of O vi/C iv, N v/C iv, and C iv/He ii that are remarkably similar for outflowing gas clouds ≲100 pc and ≈10 kpc from the nucleus. Such similarity is expected for clouds with AGN radiation-pressure-dominated dynamics. Comparing the observed line emission to models of clouds in balance with radiation pressure and/or a hot wind, we rule out the presence of a dynamically important hot wind and constrain the ratio of hot gas pressure to radiation pressure to P hot/P rad ≲ 0.25 both at ≲100 pc and ≈10 kpc from the nucleus. Moreover, the predictions of the radiation pressure confined cloud models that best fit observed UV line ratios are consistent with the observed diffuse X-ray spectrum. These results indicate that this AGN superwind is driven by radiation pressure or was driven by a hot wind that has since dissipated despite ongoing AGN activity.
AB - Galactic-scale winds driven by active galactic nuclei (AGN) are often invoked to suppress star formation in galaxy evolution models, but the mechanisms driving these outflows are hotly debated. Two key AGN feedback models are (1) radiation pressure accelerating cool gas and (2) a hot outflowing wind entraining the interstellar medium (ISM). Highly ionized emission-line diagnostics represent a powerful means of differentiating these scenarios because of their sensitivity to the expected compression of the ISM clouds by the hot wind. Here, we report the first spatially resolved UV emission spectroscopy of a prototypical (radio-quiet) quasar-driven superwind around the obscured quasar SDSS J1356+1026 at z = 0.123. We observe ratios of O vi/C iv, N v/C iv, and C iv/He ii that are remarkably similar for outflowing gas clouds ≲100 pc and ≈10 kpc from the nucleus. Such similarity is expected for clouds with AGN radiation-pressure-dominated dynamics. Comparing the observed line emission to models of clouds in balance with radiation pressure and/or a hot wind, we rule out the presence of a dynamically important hot wind and constrain the ratio of hot gas pressure to radiation pressure to P hot/P rad ≲ 0.25 both at ≲100 pc and ≈10 kpc from the nucleus. Moreover, the predictions of the radiation pressure confined cloud models that best fit observed UV line ratios are consistent with the observed diffuse X-ray spectrum. These results indicate that this AGN superwind is driven by radiation pressure or was driven by a hot wind that has since dissipated despite ongoing AGN activity.
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U2 - 10.3847/2041-8213/ab733d
DO - 10.3847/2041-8213/ab733d
M3 - Article
AN - SCOPUS:85081660380
SN - 2041-8205
VL - 890
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 2
M1 - L28
ER -