小川 翔司

Abstract We present the initial high-resolution X-ray spectroscopic observations of the Fe–K absorption structure in the luminous nearby quasar PG 1211+143, utilizing the X-ray Imaging and Spectroscopy Mission (XRISM). The primary objective is to characterize the Fe–K absorption features due to ultra-fast outflow (UFO) in this Eddington-luminosity source. Observations were conducted with XRISM’s Resolve and Xtend instruments, complemented by simultaneous data from XMM-Newton and NuSTAR. A historically bright phase was captured. The Resolve spectra clearly reveal a prominent P Cygni profile and resolves the Fe–K absorption into six distinct velocity components, ranging from v = −0.074 to −0.405 c . A similar superposition of multiple UFOs has been reported in PDS 456, suggesting that such a “UFO forest” structure may be a common feature of near Eddington-luminosity sources. Some UFO components exhibit narrow line widths of approximately σ ∼ 200 km s ⁻¹ , which may indicate that the outflows have reached their terminal velocities, thereby resulting in a smaller velocity shear. The mass outflow rate is estimated to be , which is of the order of the Eddington accretion rate. This suggests a physically plausible scenario where the outflow is a significant channel for mass ejection.

Abstract We present the first XRISM/Resolve observations of the active galactic nucleus NGC 1365, obtained in 2024 February and July. NGC 1365 is known for rapid transitions between Compton-thick and Compton-thin states, along with strong absorption from a highly ionized wind. During our observations, the source was found in a persistent low-flux state, characterized by a decrease in hard-X-ray luminosity and significant line-of-sight obscuration. In this state, XRISM/Resolve reveals clear Fe xxv and Fe xxvi absorption lines together with, for the first time in this source, corresponding emission lines. These features may arise either from reemission from a photoionized wind (P Cygni profile) or from collisionally ionized gas associated with outflow-driven shocks in the interstellar medium. We estimate the wind launch radius to be approximately 10 ¹⁶ cm (∼10 ⁴ R _g ), consistent with the location of the X-ray broadline region. We also resolve a broadened Fe K α line by σ  ∼ 1300 km s ⁻¹ , placing it at similar scales to the wind, consistent with radii inferred from disk-broadening models and the variability of the Fe K α broad line. The similarity of the Fe K α profile to the H β wing and broad Pa α width indicates that the X-ray-emitting region is likely cospatial with the optical/infrared broadline region and originates from the same gas.

Abstract We report on XRISM/Resolve spectroscopy of the recurrent transient and well-known black hole candidate 4U 1630−472 during its 2024 outburst. The source was captured at the end of a disk-dominated high/soft state at an Eddington fraction of λ _Edd ∼ 0.05 (10 M _⊙/M _BH). A variable absorption spectrum with unprecedented complexity is revealed with the Resolve calorimeter. This marks one of the lowest Eddington fractions at which highly ionized absorption has been detected in an X-ray binary. The strongest lines are fully resolved, with He-like Fe XXV separated into resonance and intercombination components and H-like Fe XXVI seen as a spin–orbit doublet. The depth of some absorption lines varied by almost an order of magnitude, far more than expected based on a 10% variation in apparent X-ray flux and ionization parameter. The velocity of some absorption components also changed significantly. Jointly modeling two flux segments with a consistent model including four photoionization zones, the spectrum can be described in terms of highly ionized but likely failed winds that sometimes show redshifts, variable obscuration that may signal asymmetric structures in the middle and outer accretion disk, and a tentative very fast outflow (v = 0.026–0.033c). We discuss the impact of these findings on our understanding of accretion and winds in stellar-mass black holes and potential consequences for future studies.

We present our study of the X-Ray Imaging and Spectroscopy Mission (XRISM) observation of the Seyfert-1 galaxy NGC 3783. XRISM’s Resolve microcalorimeter has enabled, for the first time, 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 (ξ) and column density (N_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 (1.8−3.3 keV), absorption features from Si, S, and Ar are also detected. Our spectroscopy and photoionization modeling of the time-averaged Resolve spectrum uncovers six outflow components, five of which exhibit relatively narrow absorption lines with outflow velocities ranging from 560 to 1170 km s⁻¹. In addition, a broad absorption feature is detected, which is consistent with Fe XXVI outflowing at 14 300 km s⁻¹ (0.05 c). The kinetic luminosity of this component is 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⁻¹) increases with ξ. Furthermore, we find that the column density (N_H) of the outflows generally declines with the ionization parameter up to log ξ = 3.2 but rises beyond this point, suggesting a complex ionization structure. The absorption profile of the Fe XXV resonance line is intriguingly similar to UV absorption lines (Lyα and C IV) observed by the Hubble Space Telescope, from which we infer that the outflows are clumpy in nature. Our XRISM/Resolve results from lower- and higher-ionization regimes support a “hybrid wind” scenario in which the observed outflows have multiple origins and driving mechanisms. We explore various interpretations of our findings within active galactic nucleus wind models.

Abstract We present the emission-line flux distributions and their ratios, as well as the gas outflow features, of the innermost 2 kpc region of the type 1 Seyfert galaxy Mrk 766, using the Kyoto Okayama Optical Low-dispersion Spectrograph with an optical-fiber integral field unit on the Seimei Telescope. We find that the central region of Mrk 766 is kinematically disturbed, exhibiting asymmetric and radially distributed active galactic nucleus (AGN)-driven ionized gas outflows traced by [O iii]$\lambda 5007$ with velocities exceeding 500 ${\rm km}~{\rm s}^{-1}$. The mass of the ionized gas outflow is estimated to be $10^{4.65-5.95}\, M_{\odot }$, and the mass outflow rate is 0.14–2.73 $M_{\odot }$ yr$^{-1}$. This corresponds to a kinetic power, $\dot{E}_{\rm K}$, of $4.31 \times 10^{40} \ {\rm erg} \ {\rm s^{-1 } }< \dot{E}_{\rm K} < 8.62 \times 10^{41} \ {\rm erg} \ {\rm s^{-1 } }$, which is equivalent to 0.08%–1.53% of the bolometric luminosity, $L_{\rm bol}$. This result is consistent with other observed properties of ionized gas outflows, although it is lower than the theoretical predictions in AGN feedback models ($\sim$5%), implying that ionized gas outflows traced by [O iii]$\lambda 5007$ represent only a minor fraction of the total outflows ejected from the host galaxy. Given the asymmetric and radially distributed outflow signatures observed across the host galaxy within the limited field of view, the maximum distance that the outflowing gas has traveled remains an open question.

Abstract We present ionized gas properties of nine local ultra/luminous infrared galaxies (U/LIRGs) at z < 0.04 through Integral Field Unit (IFU) observations with KOOLS-IFU on the Seimei Telescope. The observed targets are drawn from the Great Observatories All-sky LIRG Survey (GOALS), covering a wide range of merger stages. We successfully detect emission lines such as Hβ, [O iii]λ5007, Hα, [N ii]λλ6549, 6583, and [S ii]λλ6717, 6731 with a spectral resolution of R = 1500–2000, which provides (i) a spatially resolved (∼200–700 pc) moment map of ionized gas and (ii) diagnostics for an active galactic nucleus (AGN) within the central ∼3–11 kpc in diameter for our sample. We find that the [O iii] outflow that is expected to be driven by an AGN tends to be stronger (i) towards the galactic center and (ii) as a sequence of the merger stage. In particular, the outflow strength in the late-stage (stage D) mergers is about 1.5 times stronger than that in the early-state (stage B) mergers, which indicates that galaxy mergers could induce AGN-driven outflow and play an important role in the co-evolution of galaxies and supermassive black holes.