arXiv subjects

Hidehiro Kaneda

Publications and source records attributed to Hidehiro Kaneda.

At least 19 recordsLinked to original sources

arXiv2026

A systematic study of CO/SiO absorption features in early-type galaxies using AKARI/IRC near-infrared spectra

The origin of dust in early-type galaxies (ETGs) remains a long-standing question, with proposed sources being mass loss from evolved stars, galaxy mergers, or grain growth in the interstellar medium. To investigate the dominant source of dust in ETGs, we analyzed near-infrared spectra of 30 ETGs obtained with AKARI, focusing on the SiO and CO absorption features tracing the photospheres of old stellar populations. We also derived the dust mass using near- to far-infrared photometric data obtained by 2MASS, WISE, and AKARI. We find that the dust mass correlates with the summed equivalent widths of the SiO and CO absorption features. This trend suggests that a significant fraction of dust in ETGs may originate from mass loss from evolved stars, consistent with an internal production scenario. The dust mass shows no anti-correlation with diffuse X-ray luminosities, suggesting that dust in ETGs is not strongly interacting with X-ray plasma. Moreover, polycyclic aromatic hydrocarbons (PAHs) are detected in the near-infrared spectra. We find that the PAH intensity shows no correlation with the equivalent widths of SiO and CO, but correlates with the luminosity of hot and warm dust components. This suggests that PAHs may be of external origin associated with galaxy merger remnants, heated by the activities of galactic nuclei.

astro-ph.GA↗

arXiv2025

A systematic study on the aromatic and aliphatic hydrocarbon emission features of nearby galaxies using AKARI near-IR spectra

Interstellar hydrocarbon dust containing aromatic and aliphatic hydrocarbons, like polycyclic aromatic hydrocarbons (PAHs), is believed to be processed by various factors including UV radiation fields and mechanical shocks in the galactic environments. We systematically investigate the processing of hydrocarbon dust, especially the likely causes for the variations of the luminosity ratio of aliphatic to aromatic hydrocarbon emission features, using the near-infrared (IR) spectral features at wavelengths 3.3 um and 3.4-3.6 um observed with AKARI/IRC. We analyzed 243 near-IR spectra of 240 star-forming (U)LIRGs (the total IR luminosity, $L_\rm{IR}>10^{11}\ L_\odot$), 119 spectra of 105 star-forming IRGs ($10^{10}\ L_\odot<L_\rm{IR}<10^{11}\ L_\odot$), and 94 spectra of 65 sub-IRGs ($L_\rm{IR}<10^{10}\ L_\odot$), in addition to 232 spectra of 36 Galactic HII regions as a reference sample. We performed near-IR spectral model fitting to estimate the luminosities of the aromatic and aliphatic hydrocarbon features and the HI recombination line Br$\rm{\alpha}$. The result indicates that the luminosity ratios of the aliphatic to the aromatic hydrocarbons ($L_\rm{ali}/L_\rm{aro}$) in the sample galaxies show considerably large variations, compared to those in the Galactic HII regions, $L_\rm{ali}/L_\rm{aro}$ systematically decreasing with $L_\rm{IR}$ and $L_\rm{Br\alpha}$. We find that (sub-)IRGs with continuum colors bluer at 4 um tend to have higher $L_\rm{ali}/L_\rm{aro}$, which is likely to reflect the intrinsic nature of PAHs outside the HII region where the PAHs remain non-processed by strong UV radiation fields. We also find that some ULIRGs with continuum colors redder at 4 um show extremely low $L_\rm{ali}/L_\rm{aro}$, which is likely to be caused by blending aliphatic emission and absorption features due to the presence of an obscured galactic nucleus in merger systems.

astro-ph.GA↗

arXiv2025

Near-infrared [P II] and [Fe II] line mapping of Galactic supernova remnants

Phosphorus (P) is one of the key ingredients for life, yet its origins in galaxies remain poorly understood. In order to investigate the production of P by supernovae, we performed near-infrared (IR) [P II] and [Fe II] line mapping of 26 Galactic supernova remnants (SNRs) with the Infrared Survey Facility and Kanata telescopes, using the narrow-band filters tuned to these lines. By combining our data with archival [Fe II] maps from UKIRT, we detected both the [P II] and [Fe II] emissions in five SNRs, only the [Fe II] emission in 15 SNRs, and no line emissions in the remaining six. Using the observed [P II]/[Fe II] ratios and upper limits for non-detections, we derived the P/Fe abundance ratios, which vary by up to two orders of magnitude among our sample SNRs. This suggests that the production rate of P and/or the degree of dust destruction may differ from remnant to remnant, the latter being due to the fact that P is volatile while Fe is mostly locked in dust grains. We used the mid- and far-IR maps to examine the dust content for the five SNRs where both the line emissions are detected. As a result, we find that high P/Fe abundance ratios in the northern and southeastern regions of Cassiopeia A and the Crab Nebula, respectively, are not likely due to dust destruction but may reflect an asymmetric ejection of P during supernova explosions. In the Crab Nebula, it is also possible that near-IR [Ni II] emission contaminates the observed flux in the southeastern region, suggesting that the Ni/Fe abundance ratio, rather than the P/Fe abundance ratio, is relatively high in this part of the remnant.

astro-ph.GA↗

arXiv2025

A systematic study on the properties of aromatic and aliphatic hydrocarbon dust in active galactic nuclei with AKARI near-infrared spectroscopy

Recent near- and mid-infrared (IR) observations reveal the existence of appreciable amounts of aromatic and aliphatic hydrocarbon dust in the harsh environments of active galactic nuclei (AGNs), the origins of which are still under discussion. In this paper, we analyze the near-IR spectra of AGNs obtained with AKARI to systematically study the properties of the aromatic and aliphatic hydrocarbon dust a ected by the AGN activity. We perform the spectral fitting and the spectral energy distribution fitting for our sample of 102 AGNs to obtain the fluxes of the aromatic and aliphatic spectral features, the total IR luminosity (L_IR), and the fractional luminosity of AGN components (L_AGN/L_IR). As a result, we find that L_aromatic/L_IR is systematically lower for the AGN sample, especially much lower for AGNs with the aliphatic feature seen in the absorption, than for star-forming galaxies (SFGs), while L_aliphatic/L_aromatic is systematically higher for the AGN sample than for the SFG sample, increasing with the AGN activity indicated by L_AGN/L_IR. In addition, the profiles of the aliphatic emission features of the AGN sample are significantly di erent from those of the SFG sample in that the AGNs have the feature intensities systematically stronger at longer wavelengths. We conclude that both aromatic and aliphatic hydrocarbon dust are likely of circumnuclear origins, suggesting that a significant amount of the aliphatic hydrocarbon dust may come from a new population created through processes such as shattering of large carbonaceous grains by AGN outflows.

astro-ph.GA↗

arXiv2025

The PRIMA promise of deciphering interstellar dust evolution with observations of the nearby Universe

This paper develops a few science cases, using the PRIMA far-IR probe, aimed at achieving several breakthroughs in our understanding of the dust properties and their evolution. We argue that the specific observational capabilities of PRIMA, namely its unprecedented sensitivity over the whole far-IR range and the possibility to obtain continuous spectra between wavelengths 24 and 235 microns, are essential to progress in our understanding of the physics of the interstellar medium and galaxy evolution. Our science cases revolve around observations of nearby galaxies. We discuss the importance of detecting the IR emission of the diffuse interstellar medium of these galaxies, including very low-metallicity systems. We also discuss the opportunity of detecting various solid-state features to understand the mineralogy of interstellar grains. Finally, we stress the unique opportunity brought by the possible simultaneous measures of both the dust continuum and the far-IR fine-structure gas lines. These science cases could be distributed in a few large programs.

astro-ph.IM↗

arXiv2025

Magnetic fields in the massive star-forming region NGC 6334 and their relationship with the properties of dust filaments probed by [CII] and PAH emissions

We carried out the near-infrared ($JHK_{\rm s}$) imaging polarimetric observation with the polarimeter SIRPOL on the Infrared Survey Facility (IRSF) 1.4 m telescope and [CII] line mapping observation with a Fabry-P\'{e}rot spectrometer on board a 100-cm TIFR balloon-borne far-infrared telescope toward NGC 6334, and revealed the relationship between the plane-of-sky (POS) magnetic fields and [CII] emission lines to investigate the star formation in the molecular cloud. The polarization vector map shows that the POS magnetic fields are approximately perpendicular to the main filament elongation of NGC 6334. On the other hand, the POS magnetic fields tend to be parallel or random for the other filaments in NGC 6334. The [CII] emission shows a distribution well aligned with the main filament. Strong [CII] emission is also seen in the hub-filament system. Since the main filament is sandwiched between two HII regions, it is most likely that gas is efficiently accreting from the shells of the HII regions along the magnetic field resulting in active star formation. This is consistent with the NGC 6334 being bright in [CII] emission.

astro-ph.GA↗

arXiv2025

SILVIA: Ultra-precision formation flying demonstration for space-based interferometry

We propose SILVIA (Space Interferometer Laboratory Voyaging towards Innovative Applications), a mission concept designed to demonstrate ultra-precision formation flying between three spacecraft separated by 100 m. SILVIA aims to achieve sub-micrometer precision in relative distance control by integrating spacecraft sensors, laser interferometry, low-thrust and low-noise micro-propulsion for real-time measurement and control of distances and relative orientations between spacecraft. A 100-meter-scale mission in a near-circular low Earth orbit has been identified as an ideal, cost-effective setting for demonstrating SILVIA, as this configuration maintains a good balance between small relative perturbations and low risk for collision. This mission will fill the current technology gap towards future missions, including gravitational wave observatories such as DECIGO (DECihertz Interferometer Gravitational wave Observatory), designed to detect the primordial gravitational wave background, and high-contrast nulling infrared interferometers like LIFE (Large Interferometer for Exoplanets), designed for direct imaging of thermal emissions from nearby terrestrial planet candidates. The mission concept and its key technologies are outlined, paving the way for the next generation of high-precision space-based observatories.

astro-ph.IM↗

arXiv2024

Processing of hydrocarbon dust in star-forming galaxies revealed with AKARI

Hydrocarbon dust is one of the dominant components of interstellar dust, which mainly consists of polycyclic aromatic hydrocarbons and aliphatic hydrocarbons. While hydrocarbon dust is thought to be processed in interstellar radiation fields or shocks, detailed processing mechanisms are not completely understood yet. We investigate the processing of hydrocarbon dust by analyzing the relation between the luminosities emitted by hydrocarbon dust and the total infrared luminosities $(L_{\mathrm{IR}})$ for 138 star-forming galaxies at redshift $z\ <\ 0.3$. Using near-infrared 2.5-5 $\mathrm{\mu m}$ spectra obtained with AKARI, we derived the luminosities of the aromatic hydrocarbon feature at 3.3 $\mathrm{\mu m}$ ($L_\mathrm{aromatic}$) and the aliphatic hydrocarbon feature at 3.4-3.6 $\mathrm{\mu m}$ ($L_\mathrm{aliphatic}$). We also derived $L_\mathrm{IR}$ and the radiation field strength by modeling the spectral energy distributions of the 138 galaxies with AKARI, WISE and IRAS photometry data. We find that galaxies with higher $L_\mathrm{IR}$ tend to exhibit lower $L_\mathrm{aliphatic}/L_\mathrm{aromatic}$ ratios. Furthermore, we find that there is an anti-correlation between $L_\mathrm{aliphatic}/L_\mathrm{aromatic}$ ratios and the radiation field strength, and also that the galaxies with low $L_\mathrm{aliphatic}/L_\mathrm{aromatic}$ ratios are dominated by merger galaxies. These results support that hydrocarbon dust is processed through photodissociation in strong radiation fields and/or shocks during merging processes of galaxies; the $L_\mathrm{aliphatic}/L_\mathrm{aromatic}$ ratio is likely to decrease in such harsh interstellar conditions since the aliphatic bonds are known to be chemically weaker than the aromatic bonds.

astro-ph.GA↗

arXiv2023

Cosmic-ray-driven enhancement of the C$^0$/CO abundance ratio in W51C

We examine spatial variations of the C$^0$/CO abundance ratio ($X_{\mathrm{C/CO}}$) in the vicinity of the $\gamma$-ray supernova remnant W51C, based on [CI] ($^3P_1$-$^3P_0$), $^{12}$CO(1-0), and $^{13}$CO(1-0) observations with the ASTE and Nobeyama 45-m telescopes. We find that $X_{\mathrm{C/CO}}$ varies in a range of 0.02-0.16 (0.05 in median) inside the molecular clouds of $A_V>$100 mag, where photodissociation of CO by the interstellar UV is negligible. Furthermore, $X_{\mathrm{C/CO}}$ is locally enhanced up to by a factor of four near the W51C center, depending on the projected distance from the W51C center. In high-$A_V$ molecular clouds, $X_{\mathrm{C/CO}}$ is determined by the ratio of the cosmic-ray (CR) ionization rate to the H$_2$ density, and we find no clear spatial variation of the H$_2$ density against the projected distance. Hence, the high CR ionization rate may locally enhance $X_{\mathrm{C/CO}}$ near the W51C center. We also find that the observed spatial extent of the enhanced $X_{\mathrm{C/CO}}$ ($\sim$17 pc) is consistent with the diffusion distance of CRs with the energy of 100 MeV. The fact suggests that the low-energy CRs accelerated in W51C enhance $X_{\mathrm{C/CO}}$. The CR ionization rate at the $X_{\mathrm{C/CO}}$-enhanced cloud is estimated to be 3$\times$10$^{-16}$ s$^{-1}$ on the basis of time-dependent PDR simulations of $X_{\mathrm{C/CO}}$, the value of which is 30 times higher than that in the standard Galactic environment. These results demonstrate that [CI] is a powerful probe to investigate the interaction between CRs and the interstellar medium for a wide area in the vicinity of supernova remnants.

astro-ph.GA↗

arXiv2023

Properties of star formation of the Large Magellanic Cloud as probed by young stellar objects

We perform a systematic study of evolutionary stages and stellar masses of young stellar objects (YSOs) in the Large Magellanic Cloud (LMC) to investigate properties of star formation of the galaxy. There are 4825 sources in our YSO sample, which are constructed by combining the previous studies identifying YSOs in the LMC. Spectral energy distributions of the YSOs from optical to infrared wavelengths were fitted with a model consisting of stellar, polycyclic aromatic hydrocarbon and dust emissions. We utilize the stellar-to-dust luminosity ratios thus derived to study the evolutionary stages of the sources; younger YSOs are expected to show lower stellar-to-dust luminosity ratios. We find that most of the YSOs are associated with the interstellar gas across the galaxy, which are younger with more gases, suggesting that more recent star formation is associated with larger amounts of the interstellar medium (ISM). N157 shows a hint of higher stellar-to-dust luminosity ratios between active star-forming regions in the LMC, suggesting that recent star formation in N157 is possibly in later evolutionary stages. We also find that the stellar mass function tends to be bottom-heavy in supergiant shells (SGSs), indicating that gas compression by SGSs may be ineffective in compressing the ISM enough to trigger massive star formation. There is no significant difference in the stellar mass function between YSOs likely associated with the interface between colliding SGSs and those with a single SGS, suggesting that gas compression by collisions between SGSs may also be ineffective for massive star formation.

astro-ph.GA↗

arXiv2022

Simulations of the Spectral Resolving Power of a Compact Space-Borne Immersion-Echelle Spectrometer Using Mid-Infrared Wave Tracing

We performed wave-optics-based numerical simulations at mid-infrared wavelengths to investigate how the presence or absence of entrance slits and optical aberrations affect the spectral resolving power $R$ of a compact, high-spectral-resolving-power spectrometer containing an immersion-echelle grating. We tested three cases of telescope aberration (aberration-free, astigmatism and spherical aberration), assuming the aberration budget of the Space Infrared Telescope for Cosmology and Astrophysics (SPICA), which has a 20-$\mathrm{\mu m}$-wavelength diffraction limit. In cases with a slit, we found that the value of $R$ at around 10--20 $\mathrm{\mu m}$ is approximately independent of the assumed aberrations, which is significantly different from the prediction of geometrical optics. Our results also indicate that diffraction from the slit improves $R$ by enlarging the effective illuminated area on the grating window and that this improvement decreases at short wavelengths. For the slit-less cases, we found that the impact of aberrations on $R$ can be roughly estimated using the Strehl ratio.

astro-ph.IM↗

arXiv2022

Three-dimensional geometry and dust/gas ratios in massive star forming regions over the entire LMC as revealed by IRSF/SIRIUS survey

We derive the entire dust extinction (Av) map for the Large Magellanic Cloud (LMC) estimated from the color excess at near-infrared wavelengths. Using the percentile method we recently adopted to evaluate Av distribution along the line of sight, we derive the three-dimensional(3D)Av maps of the three massive star forming regions of N44, N79 and N11 based on the IRSF/SIRIUS point source catalog. The 3D AV maps are compared with the hydrogen column densities N(H) of three different velocity components where one is of the LMC disk velocity and the other two are of velocities lower than the disk velocity. As a result, we obtain 3D dust geometry suggesting that gas collision is on-going between the different velocity components. We also find difference in the timing of the gas collision between the massive star forming regions, which indicates that the gas collision in N44, N79 and N11 occurred later than that in 30 Doradus. In addition, difference by a factor of two in Av/N(H) is found between the velocity components for N44, while significant difference is not found for N79 and N11. From the 3D geometry and Av/N(H) in each star forming region, we suggest that the massive star formation in N44 was induced by an external trigger of tidal interaction between the LMC and the SMC, while that in N79 and N11 is likely to have been induced by internal triggers such as gas converging from the galactic spiral arm and expansion of a supershell although the possibility of tidal interaction cannot be ruled out.

astro-ph.GA↗

arXiv2021

Infrared Absorption and its Sources of CdZnTe at Cryogenic Temperature

To reveal the infrared absorption causes in the wavelength region between electronic and lattice absorptions, we measured the temperature dependence of the absorption coefficient of $p$-type low-resistivity ($\sim 10^2~{\rm \Omega cm}$) CdZnTe crystals. We measured the absorption coefficients of CdZnTe crystals in four-wavelength bands ($\lambda=6.45$, 10.6, 11.6, 15.1$~\mu$m) over the temperature range of $T=8.6-300$ K with an originally developed system. The CdZnTe absorption coefficient was measured to be $\alpha=0.3-0.5$ ${\rm cm^{-1}}$ at $T=300$ K and $\alpha=0.4-0.9$ ${\rm cm^{-1}}$ at $T=8.6$ K in the investigated wavelength range. With an absorption model based on transitions of free holes and holes trapped at an acceptor level, we conclude that the absorption due to free holes at $T=150-300$ K and that due to trapped-holes at $T<50$ K are dominant absorption causes in CdZnTe. We also discuss a method to predict the CdZnTe absorption coefficient at cryogenic temperature based on the room-temperature resistivity.

astro-ph.IM↗

arXiv2021

J-GEM optical and near-infrared follow-up of gravitational wave events during LIGO's and Virgo's third observing run

The Laser Interferometer Gravitational-wave Observatory Scientific Collaboration and Virgo Collaboration (LVC) sent out 56 gravitational-wave (GW) notices during the third observing run (O3). Japanese collaboration for Gravitational wave ElectroMagnetic follow-up (J-GEM) performed optical and near-infrared observations to identify and observe an electromagnetic (EM) counterpart. We constructed web-based system which enabled us to obtain and share information of candidate host galaxies for the counterpart, and status of our observations. Candidate host galaxies were selected from the GLADE catalog with a weight based on the three-dimensional GW localization map provided by LVC. We conducted galaxy-targeted and wide-field blind surveys, real-time data analysis, and visual inspection of observed galaxies. We performed galaxy-targeted follow-ups to 23 GW events during O3, and the maximum probability covered by our observations reached to 9.8%. Among them, we successfully started observations for 10 GW events within 0.5 days after the detection. This result demonstrates that our follow-up observation has a potential to constrain EM radiation models for a merger of binary neutron stars at a distance of up to $\sim$100~Mpc with a probability area of $\leq$ 500~deg$^2$.

astro-ph.HE↗

arXiv2021

Three-dimensional dust geometry of the LMC HI ridge region as revealed by the IRSF/SIRIUS survey

We present a new method to evaluate the dust extinction (AV) along the line of sight using the InfraRed Survey Facility (IRSF) near-infrared (NIR) data of the Large Magellanic Cloud (LMC) HI ridge region. In our method, we estimate an AV value for each star from the NIR color excess and sort them from bluer to redder in each line of sight. Using the percentile values of the sorted AV, we newly construct the three-dimensional AV map. We compare the resultant AV map with the total hydrogen column density N(H) traced by velocity-resolved HI and CO observations. In the LMC HI ridge region, Fukui et al. (2017, PASJ, 69, L5) find two velocity components and an intermediate velocity one bridging them. Comparing our three-dimensional AV maps with N(H) maps at the different velocities, we find that the dust geometry is consistent with the scenario of the on-going gas collision between the two velocities as suggested in the previous study. In addition, we find difference by a factor of 2 in AV/N(H) between the two velocity components, which suggests that inflow gas from the Small Magellanic Clouds (SMC) is mixed in this region. As a whole, our results support the triggered star formation in 30 Doradus due to the large-scale gas collision caused by tidal interaction between the LMC and the SMC.

astro-ph.GA↗

arXiv2021

Mid-IR cosmological spectrophotometric surveys from space: Measuring AGN and star formation at the Cosmic Noon with a SPICA-like mission

We use the SPace Infrared telescope for Cosmology and Astrophysics (SPICA) project as a template to demonstrate how deep spectrophotometric surveys covering large cosmological volumes over extended fields (1-15 square degrees) with a mid-IR imaging spectrometer (17-36 micron) in conjunction with deep 70 micron photometry with a far-IR camera, at wavelengths which are not affected by dust extinction can answer the most crucial questions in current galaxy evolution studies. A SPICA-like mission will be able for the first time to provide an unobscured three dimensional (3-D, i.e. x, y and redshift z) view of galaxy evolution back to an age of the Universe of less than ~2 Gyrs, in the mid-IR rest-frame. This survey strategy will produce a full census of the Star formation Rate (SFR) in the Universe, using Polycyclic Aromatic Hydrocarbons (PAH) bands and fine-structure ionic lines, reaching the characteristic knee of the galaxy luminosity function, where the bulk of the population is distributed, at any redshift up to z ~3.5. Deep follow-up pointed spectroscopic observations with grating spectrometers { onboard the satellite}, across the full IR spectral range (17-210 micron), would simultaneously measure Black Hole Accretion Rate (BHAR), from high-ionization fine-structure lines, and SFR, from PAH and low- to mid-ionization lines in thousands of galaxies from solar to low metallicities, down to the knee of their luminosity functions. The analysis of the resulting atlas of IR spectra will reveal the physical processes at play in evolving galaxies across cosmic time, especially its heavily dust-embedded phase during the activity peak at the cosmic noon (z ~1-3), through IR emission lines and features that are insensitive to the dust obscuration.

astro-ph.GA↗

arXiv2020

Near-infrared [FeII] and H2 line mapping of the supernova remnant IC443 with the IRSF/SIRIUS

We investigate properties of the interstellar medium (ISM) interacting with shocks around the Galactic supernova remnant IC443, using the results of near-infrared [FeII] and H2 line mapping with the IRSF/SIRIUS. In the present study, we newly performed H2 1-0 S(1) and 2-1 S(1) line mapping with the narrow-band filters tuned for these lines, covering the entire remnant (30'x35'). Combined with an [FeII] line map, our result shows that the H2 line emission is significantly detected in the southern region, while the [FeII] line emission is detected all over the remnant, suggesting that slow and fast shocks propagate through the southern region and the entire remnant, respectively. In particular, the H2 line emission is relatively strong compared to the [FeII] line emission in the southwestern region, where TeV gamma-ray emission is detected. As the strong H2 line emission indicates the dominance of the dense ISM, this result supports the scenario that the gamma-ray emission is likely to be produced through a heavy interaction between cosmic-ray protons and the dense ISM in the southwestern shell. We also find that the H2 and [FeII] line emissions show an anti-correlated spatial distribution in the same region, suggesting the presence of the clumpy ISM. Such a clumpy morphology of the ISM around IC443 may assist cosmic-ray protons to efficiently interact with large amounts of the ISM protons.

astro-ph.GA↗

arXiv2020

Pixel-based spectral characterization of mid-infrared Si array detectors for astronomical observations in space

Mid-infrared (IR) array detectors have been used for astronomical observations in space. However, the uniformities of their spectral response curves have not been investigated in detail, the understanding of which is important for spectroscopic observations using large array formats. We characterize the spectral responses of all the pixels in IR array detectors using a Fourier transform infrared spectrometer and cryogenic optics for measurements at high signal-to-noise ratios. We measured the spectral responses of the Si:As impurity band conduction (IBC) array, a flight back-up detector for AKARI/IRC. As a result, we find that the Si:As array has intrinsic variations in the spectral response along the row and column directions of the array. We also find that the cutoff wavelength of the Si:As IBC array depends on the intensity of the incident light.

astro-ph.IM↗