arXiv subjects

Shunsuke Honda

Publications and source records attributed to Shunsuke Honda.

13 recordsLinked to original sources

arXiv2026

Diversity of Ionized Gas Structures in Nearby Metal-poor Dwarf Galaxies

We investigate whether optical and far-infrared [O III] emission from nearby metal-poor dwarf galaxies can be represented by a homogeneous one-zone ionized-gas model with a single electron temperature and density. Our sample comprises five galaxies from the Herschel Dwarf Galaxy Survey: HS1222+3741, SBS0335-052E, POX186, Haro11, and IZw18. We combine galaxy-integrated or nearly galaxy-integrated [O III] 4363 and 5007 measurements from Seimei/KOOLS-IFU observations and published or archival spectroscopy with Herschel/PACS [O III] 88um measurements. Because [O III] 4363 is not detected in HS1222+3741, the analysis is based on the remaining four galaxies. SBS0335-052E and Haro11 lie near or slightly beyond the low-density boundary of the one-zone diagnostic. Their nominal line ratios favor effective densities of ne<1cm-3, while conservative treatment of the uncertainties allows values up to 40 and 10cm-3, respectively. These remain substantially below densities inferred from independent diagnostics. By contrast, POX186 and IZw18 show no significant discrepancy between the optical--far-infrared [O III] and low-ionization optical diagnostics. Additional optical and ultraviolet diagnostics show that inferred densities can span several orders of magnitude within a galaxy. Representative two-zone models reproduce the [O III] 4363, 5007, and 88um emission in SBS0335-052E and Haro11 by combining relatively dense gas with cooler, low-density gas. The low-density component contributes approximately 61% and 72% of the 88um luminosity, but only 14% and 23% of the 5007 luminosity, respectively. These solutions are not unique and may represent a broader unresolved distribution of gas conditions. Our results show that temperatures and densities inferred from integrated one-zone analyses are effective quantities and that similar diagnostic discrepancies can arise in nearby metal-poor galaxies.

astro-ph.GA↗

arXiv2026

GroundBIRD: First On-Sky Responsivity Calibration at the Teide Observatory

GroundBIRD is a cosmic microwave background (CMB) experiment located at the Teide Observatory (altitude $\sim2400$ m, Spain) designed to measure large-angular-scale intensity and polarization anisotropies ($\ell \gtrsim 6$ to $\ell \sim 300$) to constrain the reionization optical depth, $τ$. The instrument employs a rapidly rotating telescope with a fixed elevation of $70$ deg and is equipped with 161 lenslet-coupled kinetic inductance detectors (KIDs): 138 at 145 GHz for CMB observations and 23 at 220 GHz for thermal dust characterization, all operated at $\sim280$ mK. This scan strategy provides daily coverage of $\sim$40% of the Northern Hemisphere sky. We present the first on-sky responsivity calibration model for GroundBIRD, derived from repeated observations of Jupiter using the twelve most stable KIDs from GroundBIRD array 6 (GB06). The analysis establishes and validates a calibration methodology for this detector subset while providing the first empirical characterization of detector responsivity as a function of precipitable water vapor (PWV). We find that the responsivity decreases by approximately 30% across the sampled PWV range and is well described by a linear PWV-dependent model. Comparison with Moon observations reveals distinct detector operating regimes associated with different optical loading conditions. The Jupiter-based calibration achieves better than 20% precision under typical observing conditions and better than 20% relative stability over a one-month timescale. These results establish the basis for extending the calibration methodology to the full GroundBIRD focal plane.

astro-ph.IM↗

arXiv2026

Optimization procedure of the baffle of the GroundBIRD Telescope to mitigate stray light

We presented the optimization procedures of the baffle mounted on the GroundBIRD telescope for measuring the polarization of the Cosmic Microwave Background~(CMB). The telescope employs dual mirror reflective telescopes installed in a cryostat. The primary objectives were to minimize stray light contamination, maintain the integrity of the main beam, and ensure that thermal loading from the baffle remains significantly below that from the atmosphere. Using quasi-optical simulations, we have optimized the baffle's aperture angle to suppress stray light without degrading the main beam quality. We confirmed through Moon observations that the optimized baffle design works to eliminate the contamination of the stray light as expected. Furthermore, no measurable degradation in the noise equivalent temperature~(NET) was detected, indicating minimal thermal impact. These results show that our baffle optimization strategy effectively reduces systematic errors while maintaining observational sensitivity, providing valuable insights for future CMB experiments with similar optical architectures.

astro-ph.IM↗

arXiv2026

ATT12: The Antarctic 12-m Terahertz Telescope for Studies of Dusty Galaxies. I. Instrument Sensitivity and Science Forecasts

We present a feasibility study of the Antarctic 12m Terahertz Telescope (ATT12), a next-generation facility to be constructed at New Dome Fuji in Antarctica, designed to open up the FIR and THz windows for extragalactic astronomy. While ATT12 will enable a wide range of Galactic and extragalactic science, this paper focuses on its potential for studies of dusty star-forming galaxies (DSFGs) across cosmic time. Using realistic atmospheric transmission models and the planned instrumental specifications of heterodyne spectrometers and wide-field multi-color continuum cameras, we assess the expected sensitivity and scientific capabilities. We show that spectroscopic observations will enable detections of [CII]158um from galaxies with log(LIR/Lsun)>12 out to z~7, while [OIII]88um will remain observable for HyLIRG-class systems up to z~10. Line ratios including [OIII]52/88um, [NII]122/205um, and [OIII]/[NIII] will provide unique diagnostics of electron density and O/N abundance at z~4-8. Wide-field continuum surveys with the continuum cameras (KIDS-1/2; 300-850 GHz) will reach confusion-limited depths of ~1-2 mJy over ~10,000 deg$^2$, detecting of order $10^{6}$-$10^{7}$ DSFGs with log(LIR/Lsun)>12 at z<5 and $\lesssim10^{3}$--$10^{4}$ HyLIRGs up to z~7 or higher. Higher-frequency cameras (KIDS-3/4; >850 GHz) are designed for targeted follow-up observations and to extend coverage toward the THz regime. Taken together, ATT12 will provide the first statistically representative samples of DSFGs across cosmic time and, through synergy with ALMA, JWST, and the proposed FIR Probe PRIMA, will establish a multi-wavelength framework in which ATT12 discovers large samples through wide-area surveys, ALMA provides high-resolution follow-up of gas and ISM structure, JWST probes stellar populations and metallicity in the rest-frame optical/NIR, and PRIMA delivers ultra-sensitive FIR spectroscopy.

astro-ph.GA↗

arXiv2026

GroundBIRD Telescope: Systematics Modelization of MKID Arrays Response

Kinetic inductance detectors are widely used in millimeter- and submillimeter-wave astronomy, benefiting from their fast response and relative ease of fabrication. The GroundBIRD telescope employs microwave kinetic inductance detectors at 145 and 220 GHz to observe the cosmic microwave background. As a ground-based telescope, it is subject to inherent environmental systematics, namely atmospheric emission and thermal fluctuations of the focal plane temperature. This study models resonance frequency shifts induced by each source using calibrated on-site measurements of precipitable water vapor and temperature. Comparison with observational data confirms the validity of the models and identifies atmospheric loading as the dominant contributor to frequency variation under typical observation conditions.

astro-ph.IM↗

arXiv2024

Commissioning the CMB polarization telescope GroundBIRD with the full set of detectors

GroundBIRD is a ground-based cosmic microwave background (CMB) experiment for observing the polarization pattern imprinted on large angular scales ($\ell > 6$ ) from the Teide Observatory in Tenerife, Spain. Our primary scientific objective is a precise measurement of the optical depth $τ$ ($σ(τ) \sim 0.01$) to the reionization epoch of the Universe to cross-check systematic effects in the measurements made by previous experiments. GroundBIRD observes a wide sky area in the Northern Hemisphere ($\sim 40\%$ of the full sky) while continuously rotating the telescope at a high speed of up to 20 rotations per minute (rpm) to overcome the fluctuations of atmospheric radiation. We have adopted the NbTiN/Al hybrid microwave kinetic inductance detectors (MKIDs) as focal plane detectors. We observe two frequency bands centered at 145 GHz and 220 GHz. The 145 GHz band picks up the peak frequency of the CMB spectrum. The 220 GHz band helps accurate removal of the contamination of thermal emission from the Galactic interstellar dust. The MKID arrays (138 MKIDs for 145GHz and 23 MKIDs for 220GHz) were designed and optimized so as to minimize the contamination of the two-level-system noise and maximize the sensitivity. The MKID arrays were successfully installed in May 2023 after the performance verification tests were performed at a laboratory. GroundBIRD has been upgraded to use the full MKID arrays, and scientific observations are now underway. The telescope is automated, so that all observations are performed remotely. Initial validations, including polarization response tests and observations of Jupiter and the moon, have been completed successfully. We are now running scientific observations.

astro-ph.IM↗

arXiv2023

Search for Dark Photon Dark Matter in the Mass Range $74\mbox{--}110\,μ\mathrm{eV}/c^2$ with a Cryogenic Millimeter-Wave Receiver

We search for the dark photon dark matter (DPDM) using a cryogenic millimeter-wave receiver. DPDM has a kinetic coupling with electromagnetic fields with a coupling constant of $χ$, and is converted into ordinary photons at the surface of a metal plate. We search for signal of this conversion in the frequency range $18\text{--}26.5\,\mathrm{GHz}$, which corresponds to the mass range $74\text{--}110\,mu\mathrm{eV}/c^2$. We observed no significant signal excess, allowing us to set an upper bound of $χ< (0.3\text{--}2.0)\times 10^{-10}$ at 95\% confidence level. This is the most stringent constraint to date, and tighter than cosmological constraints. Improvements from previous studies are obtained by employing a cryogenic optical path and a fast spectrometer.

hep-ex↗

arXiv2022

Characterization of two-level system noise for microwave kinetic inductance detector comprising niobium film on silicon substrate

A microwave kinetic inductance detector (MKID) is a cutting-edge superconducting detector. It comprises a resonator circuit constructed with a superconducting film on a dielectric substrate. To expand its field of application, it is important to establish a method to suppress the two-level system (TLS) noise that is caused by the electric fluctuations between the two energy states at the surface of the substrate. The electric field density can be decreased by expanding the strip width (S) and gap width from the ground plane (W) in the MKID circuit, allowing the suppression of TLS noise. However, this effect has not yet been confirmed for MKIDs made with niobium films on silicon substrates. In this study, we demonstrate its effectiveness for such MKIDs. We expanded the dimension of the circuit from (S, W) = (3.00 $μ$m, 4.00 $μ$m) to (S, W) = (5.00 $μ$m, 23.7 $μ$m), and achieved an increased suppression of 5.5 dB in TLS noise.

physics.ins-det↗

arXiv2021

A forecast of the sensitivity on the measurement of the optical depth to reionization with the GroundBIRD experiment

We compute the expected sensitivity on measurements of optical depth to reionization for a ground-based experiment at Teide Observatory. We simulate polarized partial sky maps for the GroundBIRD experiment at the frequencies 145 and 220 GHz. We perform fits for the simulated maps with our pixel-based likelihood to extract the optical depth to reionization. The noise levels of polarization maps are estimated as 110 $μ\mathrm{K~arcmin}$ and 780 $ μ\mathrm{K~arcmin}$ for 145 and 220 GHz, respectively, by assuming a three-year observing campaign and sky coverages of 0.537 for 145 GHz and 0.462 for 220 GHz. Our sensitivities for the optical depth to reionization are found to be $σ_τ$=0.030 with the simulated GroundBIRD maps, and $σ_τ$=0.012 by combining with the simulated QUIJOTE maps at 11, 13, 17, 19, 30, and 40 GHz.

astro-ph.CO↗

arXiv2020

GroundBIRD : A CMB polarization experiment with MKID arrays

GroundBIRD is a ground-based experiment for the precise observation of the polarization of the cosmic microwave background (CMB). To achieve high sensitivity at large angular scale, we adopt three features in this experiment: fast rotation scanning, microwave kinetic inductance detector (MKID) and cold optics. The rotation scanning strategy has the advantage to suppress $1/f$ noise. It also provides a large sky coverage of 40\%, which corresponds to the large angular scales of $l \sim 6$. This allows us to constrain the tensor-to-scalar ratio by using low $l$ B-mode spectrum. The focal plane consists of 7 MKID arrays for two target frequencies, 145 GHz and 220 GHz band. There are 161 pixels in total, of which 138 are for 144 GHz and 23 are for 220 GHz. This array is currently under development and the prototype will soon be evaluated in telescope. The GroundBIRD telescope will observe the CMB at the Teide observatory. The telescope was moved from Japan to Tenerife and is now under test. We present the status and plan of the GroundBIRD experiment.

astro-ph.IM↗

arXiv2015

TID-Effect Compensation and Sensor-Circuit Cross-Talk Suppression in Double-SOI Devices

We are developing double silicon-on-insulator (DSOI) pixel sensors for various applications such as for high-energy experiments. The performance of DSOI devices has been evaluated including total ionization damage (TID) effect compensation in transistors using a test-element-group (TEG) up to 2 MGy and in integration-type sensors up to 100 kGy. In this article, successful TID compensation in a pixel-ASD-readout-circuit is shown up to 100 kGy for the application of DSOI to counting-type sensors. The cross-talk suppression in DSOI is being evaluated. These results encourage us that DSOI sensors are applicable to future high-energy experiments such as the BELLE-II experiment or the ILC experiment.

physics.ins-det↗

arXiv2015

Compensation for TID Damage in SOI Pixel Devices

We are investigating adaption of SOI pixel devices for future high energy physic(HEP) experiments. The pixel sensors are required to be operational in very severe radiation environment. Most challenging issue in the adoption is the TID (total ionizing dose) damage where holes trapped in oxide layers affect the operation of nearby transistors. We have introduced a second SOI layer - SOI2 beneath the BOX (Buried OXide) layer - in order to compensate for the TID effect by applying a negative voltage to this electrode to cancel the effect caused by accumulated positive holes. In this paper, the TID effects caused by Co gamma-ray irradiation are presented based on the transistor characteristics measurements. The irradiation was carried out in various biasing conditions to investigate hole accumulation dependence on the potential configurations. We also compare the data with samples irradiated with X-ray. Since we observed a fair agreement between the two irradiation datasets, the TID effects have been investigated in a wide dose range from 100~Gy to 2~MGy.

physics.ins-det↗

arXiv2015

Characteristics of Non-Irradiated and Irradiated Double SOI Integration Type Sensor

We are developing monolithic pixel sensors based on a 0.2 $μ$m fully-depleted Silicon-on-Insulator (SOI) technology for HEP experiment applications. The total ionizing dose (TID) effect is the major issue in the applications for hard radiation environments in HEP experiments. To compensate for TID damage, we have introduced a Double SOI structure which has a Middle Silicon layer (SOI2 layer) in addition. We studied the recovery from TID damage induced by $\mathrm{^{60}Co}~γ$'s and other characteristics of an Integration-type Double SOI sensor. The Double SOI sensor irradiated to 100 kGy showed a response for IR laser similar to of a non-irradiated sensor when we applied a negative voltage to the SOI2 layer. We conclude that the Double SOI sensor is radiation hard enough to be used in HEP experiments in harsh radiation environments such as at Bell II or ILC.

physics.ins-det↗