arXiv subjects

Erika Ogata

Publications and source records attributed to Erika Ogata.

3 recordsLinked to original sources

arXiv2026

Development of TIFUUN: Terahertz Integral Field Units with Universal Nanotechnology

TIFUUN (THz Integral Field Units with Universal Nanotechnology) is an ultra-wideband mm-submm wave imaging spectrometer that capitalizes on the highly scalable integrated superconducting spectrometer technology. TIFUUN has two slots for integral field units (IFUs), which can jointly be optimized as open-hardware for each astronomical observation in terms of spatial and spectral coverage. These IFUs can have observation frequencies in the range of 90--360 GHz, with spectral resolution up to $R\equiv F/ΔF \le 1,000$, with up to $\sim$18,000 kinetic inductance detectors (shared by the two IFUs with a flexible ratio). The ultra-wide 4:1 (2 octave) bandwidth optics fits in a remarkably compact volume, by means of thin silicon lenses and a high chief ray angle design. The first pair of IFUs are being developed for the SUBLIME (Study of the Universe By Line Intensity Mapping Experiments) experiment that aims to map CII emission at redshift $\sim$6 to trace the cosmic large-scale structure and the buildup of galaxies during reionization, using TIFUUN on the ASTE 10-m telescope. The scalability, flexibility and compactness makes TIFUUN a highly compatible and portable system suited also for upcoming telescope facilities in the vicinity, such as FYST and AtLAST/LST.

astro-ph.IM↗

arXiv2026

Signatures of Accreting Black Holes in Line Intensity Mapping

Line-intensity mapping (LIM) has attracted growing attention as a powerful technique for probing the large-scale distribution of galaxies and the cosmic history of star formation through unresolved line emission. Existing LIM models for galaxy-associated lines, such as H$α$, often assume that the dominant contribution to observed emission arises from star-forming activity, while the role of accreting black holes (BHs) remains largely unexplored. In this study, we use the IllustrisTNG cosmological hydrodynamical simulation to construct mock intensity maps of H$α$ and He II, including contributions from both star formation and BH accretion. We show that the BH contribution to the mean intensity is significant, reaching $\sim$40--60 per cent for H$α$ and $\sim$60--80 per cent for He II around cosmic noon. Owing to the large luminosity weight of rare, bright sources, BH-powered emission dominates the shot-noise component of the power spectrum and significantly boosts the small-scale clustering amplitude, particularly for He II. We assess the implications for forthcoming LIM surveys and show that SPHEREx can probe the BH-influenced bright end of the H$α$ voxel intensity distribution (VID) at $z\lesssim4$, and a CDIM-like experiment can further access the BH-dominated regime of He II. Our results demonstrate that accreting BHs represent an essential component of LIM signals, which was previously underappreciated. We thus conclude that accurately modeling the BH contribution is crucial for a physically complete interpretation of future LIM observations.

astro-ph.GA↗

arXiv2024

Three-dimensional radiation hydrodynamics simulations of wandering intermediate-mass black holes considering the anisotropic radiation and dust sublimation

By performing three-dimensional radiation hydrodynamics simulations, we study Bondi-Hoyle-Lyttleton accretion onto intermediate-mass black holes (BHs) wandering in the dusty gas. Here, we take into account the anisotropic radiation feedback and the sublimation of dust grains. Our simulations show that when the relative velocity between the BH and the gas is small (~20 km/s) and gas density is ~10^4/cm^3, the gas mainly accretes from near the equatorial plane of the accretion disk at a time-averaged rate of 0.6% of the Bondi-Hoyle-Lyttleton rate. An ionized region like two spheres glued together at the equatorial plane is formed, and the dense shock shell appears near the ionization front. The BH is accelerated at ~10^-8cm/s^2 due to the gravity of the shell. For denser gas (~10^6/cm^3), the time-averaged accretion rate is also 0.6% of the Bondi-Hoyle-Lyttleton rate.However, the BH is decelerated at ~10^-7cm/s^2 due to gravity of the dense downstream gas although the dense shock shell appears upstream. Our simulations imply that intermediate-mass BHs in the early universe keep floating at > several 10km/s without increasing mass in interstellar gas with density of ~10^4/cm^3, and slow down and grow into supermassive BHs in galaxies with the density of ~10^6/cm^3.

astro-ph.GA↗