Publications

KOOLS-IFU observations on the 3.8 m Seimei Telescope map the central ∼2 kpc of NGC 6552. The [O III]λ5007 width declines with radius, consistent with a decelerating central outflow, yet neither W80 nor Δv correlates significantly with [O III]/Hβ.

Hector IFS and archival Chandra data reveal a compact nuclear X-ray source in a galaxy with extended LINER-like emission. Spatially resolved photon-budget maps show that evolved stars alone cannot supply the required ionizing photons, which points to a weak LLAGN.

A Vision Transformer trained on ∼124,000 SDSS gri composite images identifies star-forming galaxies from JPEG images alone. The approach bypasses emission-line diagnostics and is aimed at Euclid, DES, and LSST.

KOOLS-IFU data reveal asymmetric, radially distributed ionized outflows faster than 500 km s⁻¹ in the inner 2 kpc of Mrk 766. The kinetic power corresponds to 0.08% to 1.53% of the bolometric luminosity.

Optical emission-line measurements and AGN demographics for 743 of the 746 unbeamed AGN in the 70-month Swift-BAT catalog. Hard X-ray selection recovers a more heavily reddened population than optical selection in SDSS.

Four AGN are identified in isolated compact elliptical galaxies, with black hole masses of 7×10⁵ to 8×10⁷ M☉. The hosts follow the observed black hole scaling relations, which supports a nature origin for isolated cEs.

FMOS near-infrared spectra of X-ray-selected broad-line AGN at 0.6 < z < 1.7 show the same anti-correlation between Eddington ratio and [N II]λ6583/Hα that is found in local hard X-ray-selected AGN.

A uniform all-sky survey in the 14 to 195 keV band, including 423 new hard X-ray detections, released with eight-channel spectra and monthly sampled light curves for each source.

For nearby hard X-ray selected AGN from BASS, the [N II]λ6583/Hα ratio shows a significant anti-correlation with the Eddington ratio that is not driven solely by black hole mass or bolometric luminosity. The ratio is proposed as an indicator of the Eddington ratio with an rms scatter of about 0.6 dex.

A new catalog of type 1 AGN at z < 0.2 reveals a large population of galaxies with weak broad-line regions. The type 1 fraction, a measure of the average torus opening angle, is not set by black hole mass or bolometric luminosity alone, which indicates that the receding torus model is only partially valid.

Statistical properties of a volume-limited sample of 7429 nearby galaxies at 0.033 < z < 0.044 from SDSS DR7. Visual morphologies are combined with structural and spectroscopic properties from the OSSY catalog, which confirms the known correlations between morphology, line strengths, and stellar ages.

Emission- and absorption-line measurements for 664,187 SDSS galaxies at z < 0.2, obtained by separating nebular emission from stellar absorption with empirical stellar templates. The public OSSY database also provides a quality parameter that assesses each spectral fit.