Kavli Affiliate: Erin Kara
| First 5 Authors: Missagh Mehdipour, Jelle S. Kaastra, Megan E. Eckart, Liyi Gu, Ralf Ballhausen
| Summary:
We present our study of the XRISM observation of the Seyfert-1 galaxy NGC
3783. For the first time, XRISM’s Resolve microcalorimeter enables a detailed
characterization of the highly ionized outflows in this active galactic
nucleus. Our analysis constrains their outflow and turbulent velocities, along
with their ionization parameter $xi$ and column density $N_{rm H}$. The
high-resolution Resolve spectrum reveals a distinct series of Fe absorption
lines between 6.4 and 7.8 keV, ranging from Fe XVIII to Fe XXVI. At lower
energies, absorption features from Si, S, and Ar are also detected. Our
spectroscopy and photoionization modeling of the time-averaged Resolve spectrum
uncover six outflow components, five of which exhibit relatively narrow
absorption lines, with outflow velocities ranging from 560 to 1170 km/s. In
addition, a broad absorption feature is detected, which is consistent with Fe
XXVI outflowing at 14,300 km/s (0.05 $c$). This component carries a kinetic
luminosity of 0.8-3% of the bolometric luminosity. Our analysis of the Resolve
spectrum shows that more highly ionized absorption lines are intrinsically
broader than those of lower ionization species, indicating that the turbulent
velocity of the six outflow components (ranging from 0 to 3500 km/s) increases
with $xi$. Furthermore, we find that the $N_{rm H}$ of the outflows generally
declines with $xi$ up to $log xi = 3.2$, but rises beyond this point,
suggesting a complex ionization structure. Examination of the absorption
profile of the Fe XXV resonance line reveals intriguing similarities to UV
absorption lines (Ly$alpha$ and C IV) observed by the HST, from which we infer
that the outflows are clumpy in nature. Our XRISM/Resolve results support a
‘hybrid wind’ scenario, in which the outflows have multiple origins and driving
mechanisms. We explore various interpretations of our findings within AGN wind
models.
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