Instrumentation and Methods for Astrophysics · Cross-listed from hep-ph
Transient PULSE: Code for the Transient Propagation of UltraLight (pseudo)Scalars to Earth
Jason Arakawa, Charles Cheung, Muhammad Hani Zaheer et al. (+2 more)
We present Transient PULSE, a software package that numerically implements a previously developed source-to-detector framework for transient ultralight bosonic signals from astrophysical bursts. Predicting these signals relies on connecting the source emission spectrum to its
evolution during propagation and the resulting observables at a terrestrial detector. The package discretizes a user supplied energy spectrum into momentum modes, propagates them through a specified matter density profile and constructs the time-frequency energy density distribution at Earth, accounting for dispersion and in-medium screening effects. This treatment accommodates non-Gaussian source spectra and provides inputs for detector specific analyses. A complementary analytical module estimates coupling sensitivities, arrival time delays and screening thresholds from parameterized source and detector properties.
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All authors Jason Arakawa, Charles Cheung, Muhammad Hani Zaheer, Volodymyr Takhistov, Marianna Safronova
Instrumentation and Methods for Astrophysics
International Astrophysical Consortium for High-energy Calibration: Summary of the 18th IACHEC Workshop
K. K. Madsen, C. E. Grant, V. Burwitz et al. (+14 more)
In this report we summarize the activities of the International Astronomical Consortium for High Energy Calibration (IACHEC) from the 18th IACHEC Workshop at Pelham, Germany. Fifty-six scientists directly involved in the calibration of operational and future high-energy missions gathered during four days to discuss the status of the cross-calibration between the current international complement of X-ray observatories, and the possibilities to improve it. This summary consists of reports from the Working Groups with topics ranging across: the identification and characterization of standard calibration sources, multi-observatory cross-calibration campaigns, appropriate and new statistical techniques, calibration of instruments and characterization of background, preservation of knowledge, and results for the benefit of the astronomical community.
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All authors K. K. Madsen, C. E. Grant, V. Burwitz, H. Earnshaw, K. Forster, M. Guainazzi, V. L. Kashyap, H. L. Marshall, C. B. Markwardt, F. Meeker-Fürst, E. D. Miller, L. Natalucci, P. P. Plucinsky, M. Shidatsu, H. Suzuki, Y. Terada, A. Tümer
Instrumentation and Methods for Astrophysics
Refurbishment and Cryocooler Upgrade of the CPAPIR Wide-Field Near-Infrared Camera: Design, Integration, and Lessons Learned
Philippe Vallee, Jonathan St-Antoine, Lison Malo et al. (+5 more)
The CAmera PAnoramique Proche Infrarouge (CPAPIR) is a wide-field near-infrared imager that has been operating at the Observatoire du Mont-Mégantic (OMM) since 2004. After more than two decades of service, the instrument required a major refurbishment due to detector degradation, including the loss of one quadrant, as well as operational constraints associated with its
liquid-nitrogen cooling system. To extend the instrument's lifetime and reduce maintenance requirements, the detector was replaced and the cooling system upgraded through the integration of a Sunpower CryoTel DS30 cryocooler. This paper presents the thermal and mechanical redesign of the instrument, including finite element analysis (FEA), three-dimensional CAD modeling, hardware selection, and laboratory validation. Particular
attention is given to the challenges encountered during integration and testing, notably vibration mitigation and cryogenic system implementation. The resulting performance improvements and lessons learned from the upgrade are discussed. The upgraded instrument is scheduled for on-sky commissioning at the Observatoire du Mont-Mégantic in summer 2026.
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All authors Philippe Vallee, Jonathan St-Antoine, Lison Malo, Frederique Baron, Sylvie F Beaulieu, Rene Doyon, Etienne Artigau, Fidele Robichaud
Instrumentation and Methods for Astrophysics · Cross-listed from astro-ph.GA
The contact frontier in Galactic civilization networks: radial structure and the Galactic habitable zone
Kohji Tsumura
The probability of interstellar contact depends not only on the abundance of technological civilizations but also on their spatial connectivity. Treating civilizations as nodes linked whenever their separation is smaller than the distance a signal travels within a communicative lifetime, we determine the radial structure of Galactic civilization networks. An exponential stellar disc replaces the uniform disc of earlier work, and the fraction of
stars hosting civilizations may vary with radius as a Galactic Habitable Zone (GHZ). The isolation, contact and network transitions are frontiers several kiloparsecs wide, not boundaries: the contact frontier is set entirely by the disc scale length, and the network frontier, broadened by gradient percolation, stays near 1.5 scale lengths. The two frontiers overlap over a band containing the Sun, where both transitions proceed at once. Within this factorized GHZ model, the radius of peak civilization density depends only logarithmically on the strength of
supernova sterilization, and the wide range of published peak radii, from the Galactic centre to 12 kpc, is reproduced primarily by varying that one parameter. Under the present normalization, the location of the zone has only a modest effect on the local contact probability, whereas the modelled Galactic connectivity is minimized when the civilization-density peak lies near the solar Galactocentric radius, where current determinations place the peak.
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Instrumentation and Methods for Astrophysics · Cross-listed from astro-ph.CO
Joint Line Intensity Recovery from Multi-Tracer Cross-Correlations
Carlos E. Sierra and Kirit S. Karkare
Line intensity mapping (LIM) provides a unique window into the high-
redshift universe, but the separation of signals from overlapping emission lines and bright continuum foregrounds remains a central analysis challenge. At millimeter wavelengths in particular, [CII], [CI] and numerous CO transitions overlap with comparable brightness, leading to significant spectral confusion. This work presents a joint likelihood framework that incorporates multi-tracer cross-correlations both between distinct LIM tracers and with external
galaxy surveys. By jointly fitting all auto- and cross-spectra between the LIM and
galaxy data, this approach combines the spatial and spectral information in each
dataset to break degeneracies between overlapping lines and recover individual bias-weighted line intensities at fixed cosmology, even at
redshifts where no direct cross-correlation is available. We validate this framework on realistic mocks of an extended SPT-SLIM-like survey spanning 125-175 GHz over 100 deg$^2$, combined with an LSST Y1-like photometric
galaxy catalog, and recover CO(2-1) through CO(6-5) and [CI](1-0) over $0.3\lesssim z\lesssim4$ in the presence of bright continuum foregrounds. We demonstrate that adding the photometric
galaxy data tightens line constraints by a factor of $\sim$3-4 where the
galaxies overlap the lines in
redshift, and by $\sim$20-50% at higher
redshifts beyond the
galaxy coverage, where the gain comes indirectly from constraining the low-
redshift interlopers. These results highlight external tracer overlap as a primary consideration when optimizing the frequency coverage and footprint of near-future LIM experiments.
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Instrumentation and Methods for Astrophysics
Updates to STIS NUV Dark Calibration
Jacqueline Brown, Sean Lockwood, TalaWanda Monroe et al. (+2 more)
We present new superdark calibration files (DARKFILEs) and a new dark correction table (TDCTAB) for use with data taken by the Space
Telescope Imaging Spectrograph near-ultraviolet microchannel array (STIS NUV-MAMA) detector for HST Cycle 19 onward. These superdarks include 12 years of NUV dark exposures and make use of an updated temperature scaling equation developed in 2013 to more accurately characterize the dark rate. In tested
datasets, the new superdarks provide an average 3% increase in SNR and smooth out a ring artifact left previously by oversubtraction of the dark rate. The new superdarks and TDCTAB have been delivered to the Calibration Reference Data System (CRDS) and have been used to recalibrate all affected
datasets in the Mikulski Archive for Space
Telescopes (MAST).
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All authors Jacqueline Brown, Sean Lockwood, TalaWanda Monroe, Amy Jones, Joleen Carlberg
Instrumentation and Methods for Astrophysics
Geometrical and Optical Design of the GUEST Laser-Ranged Test Masses for the Detection of Gravitational Waves in the $\mu$Hz range
Dario Vetrano, Giada Bargiacchi, Nicolò Burzillà et al. (+5 more)
The GUEST (Gravitational Universe Exploration with Satellite Tracking) mission aims at detecting gravitational waves in the yet almost unexplored $\mu$Hz frequency range through high-precision orbital tracking. The unprecedented scientific objectives of this experiment demand equally advanced optical solutions: the highly eccentric orbit imposes dual measurement regimes; a low-velocity, long-range scenario at apogee and a high-velocity, short-range scenario at perigee. The substantial disparity between these conditions is addressed through a novel optical architecture incorporating two distinct types of Corner-Cube Retroreflectors (CCRs) with 1" and 2" apertures (CCR1 and CCR2, respectively). The proposed layout has been designed to ensure isotropy and homogeneity of the optical response while maintaining efficient packing over the spherical surface of the spacecraft. The resulting Optical Cross-Section (OCS) has been evaluated using a custom reduced-order model, which captures the behavior of individual CCRs under varying illumination conditions. This model has been calibrated by reconstructing the optical response of the LARES-2 satellite and has enabled a detailed assessment of the contributions of each CCR type along the GUEST orbit. Finally, sensitivity analyses have been conducted to investigate the impact of key design parameters, including the ratio between CCR types,
laser wavelength, spacecraft diameter, Dihedral Angle Offsets (DAOs), and mechanical configurations.
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All authors Dario Vetrano, Giada Bargiacchi, Nicolò Burzillà, Roberto Campagnola, Francesco Del Ferraro Iacobelli, Luca Porcelli, Simone Dell'Agnello, Diego Blas
Instrumentation and Methods for Astrophysics · Cross-listed from astro-ph.SR
Revisiting the Optical F-corona from the Artemis II Total Solar Eclipse with RAW Data: How Far Can Consumer JPEG Images Be Trusted for Astronomical Photometry?
Kohji Tsumura and Ko Arimatsu
We reanalyze the total solar eclipse images taken with a consumer camera during the Artemis II lunar flyby, using the RAW data as ground truth for our previous analysis of the released JPEG image. Calibrated with field
stars, the RAW data show that the lens vignetting and the variation of the pixel solid angle reduce the signal of diffuse light by up to $\sim$70% at the edge of the field, and that the signal on the dark side of the Moon is most likely foreground light rather than an instrumental offset. Between 10 degrees and 15 degrees elongation, the radial profiles of the F-corona follow power laws with indices of $-2.0$ to $-2.3$ (east), $-2.5$ (west), and $-2.4$ to $-2.7$ (north and south), consistent with space-based observations, and the surface brightness along the ecliptic is $\sim$26 MJy sr$^{-1}$ ($\pm 7\%$) at 10 degrees. The isophotes have flattening indices of $\sim$0.6-0.7 and superellipse indices of $\sim$1.5-1.6. Comparison with the ZodiSURF zodiacal light model supports a radial dust density index of $\alpha \simeq 1.3$ down to $\sim$0.2 au and suggests that the vertical distribution of the dust broadens toward the Sun. The JPEG image retains nearly the full vignetting, despite its metadata, and its tone response is not a single power law; together with the zero-point treatment, these effects account for the steep and asymmetric profiles reported previously, while the flattened morphology and $\alpha \simeq 1.3$ are confirmed. We identify quantities robust in JPEG images and show that the tone response can be reconstructed from field
stars.
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Instrumentation and Methods for Astrophysics
R&D activity in INAF on light instrumentation for continuous optical turbulence monitoring
Camilo Weinberger Elena Masciadri, Luca Carbonaro, Marlene de Sepibus et al. (+4 more)
Measurements of optical
turbulence are essential in both ground-based astronomy and free-space optical communication systems contexts for multiple reasons including supporting and optimizing Adaptive Optics. Similarly, forecasting these parameters is highly valuable for planning observational campaigns; however, it requires at least two years of continuous data to generate a reliable training
dataset. The most commonly used instruments to monitor continuously the optical
turbulence include DIMM, MASS, SLODAR, RINGSS sensors. The Arcetri team is leading two operational forecast systems for two different Observatories: ALTA above LBT, and FATE above VLT. Both systems are in continuous
evolution and obviously forecast performances depend also on available measurements. Our long-term goal is to develop our own instruments to obtain continuous measurements directly from local observations. In this work, we present an automated system designed for continuous seeing measurements using multiple sensors. This portable station integrates a Cyclope, a RINGSS unit, a scintillometer which operate together to provide comprehensive night-time atmospheric information. We will compare the performance of low-cost sensors, such as the Cyclope and the scintillometer, with that of the RINGSS
turbulence profiler, which has been fully installed and programmed by our team in collaboration of LBT team. A dedicated insturment for night and day-time measurements is planned for near future. This system incorporates a fully automatic on-site system that monitors operational status, delivers real-time information on sensor conditions and measurements, and manages synchronization with the data storage unit. The system's real-time acquisition capability enables continuous
turbulence analysis, supports R&D activities, facilitates local data generation, and allows on-site testing of forecasting methodologies.
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All authors Camilo Weinberger Elena Masciadri, Luca Carbonaro, Marlene de Sepibus, Fernando Pedichini, Ciro Del Vecchio, Christian Veillet, Sam Ragland
Instrumentation and Methods for Astrophysics · Cross-listed from gr-qc
Quantum noise and torque correlations in a torsion-bar Sagnac speed meter
Yuki Inoue, Mario Onglao, Daiki Tanabe et al. (+3 more)
Quantum fluctuations entering through weakly transmitting mirrors can limit a torsion-bar Sagnac speed meter for low-frequency gravitational-wave detection, even when its optical layout suppresses radiation-pressure back action. We show that, in the Cryogenic sub-Hz cROss torsion bar detector with
quantum NOn-demolition Speed meter (CHRONOS),
vacuum fields entering from behind the end and middle test masses can dominate the low-frequency
quantum noise despite cancellation of the torques on opposite ends of each bar. For a reference configuration with mirror power transmissions of only $10^{-7}$, these fields contribute $89.7\%$ of the total
quantum-noise power spectral density at 0.1 Hz. Omitting them would underestimate the amplitude spectral density by a factor of 3.11. Our input-output model connects the correlations produced by successive optical interactions to the forces on each bar and the measured signal. This connection shows why strong torque cancellation does not, by itself, ensure a corresponding improvement in detector sensitivity. Replacing mirror transmission with absorption at fixed reflectivity leaves the excess
quantum noise essentially unchanged for the two operating points studied. The predicted signal response and
quantum noise agree with independent FINESSE 3 calculations as recycling detuning and homodyne angle are varied. These results establish rear
vacuum fields as a limiting noise source in this torsion-bar speed meter and provide quantitative requirements for its mirror and readout design.
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All authors Yuki Inoue, Mario Onglao, Daiki Tanabe, Masashi Hazumi, Vivek Kumar, Apimook Watcharangkool
Instrumentation and Methods for Astrophysics
RPCA: a Resolved PSF reconstruction method for undersampled images
Lin Nie, Huanyuan Shan, Guoliang Li et al. (+11 more)
The Point-Spread Function (PSF) is a critical component in various astrophysical research areas, including
galaxy morphology, photometric
redshift determination, and weak
lensing studies. As the next generation of space
telescopes prepares for operations, including the China Space Station
Telescope (CSST), accurate PSF modeling has become increasingly important. However, accurately modeling the PSF remains challenging, particularly for poorly sampled images. To construct reliable PSF models based on
star images, we aim to develop a novel and robust method, which accounts for the pixel integration effect in modeling for reconstructing high-resolution PSFs from undersampled or poorly resolved images. In this paper, we present Resolved Principal Components Analysis (RPCA), a novel approach that accounts for pixel integration effects to enable the direct reconstruction of resolved PSFs from undersampled images via an Expectation-Maximization PCA (EMPCA) technique. Our method has been tested on a simulated PSF
dataset for the China Space Station
Telescope (CSST), where both observational and detector-induced effects were considered during simulation. The results demonstrate that RPCA achieves superior precision in PSF shape parameters compared to existing methods such as Multi-CCD (MCCD), Resolved Components Analysis (RCA), and PSFEx. Notably, RPCA {could reduce the bias of $\Delta R^2/R^2$ by approximately one order of magnitude with respect to MCCD, RCA and PSFEx. RPCA exhibits robust stability under realistic observational conditions, including varying signal-to-noise ratios (SNRs) and contamination from
cosmic rays and bad pixels. This suggests that RPCA could be a promising candidate for future CSST PSF modeling efforts.
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All authors Lin Nie, Huanyuan Shan, Guoliang Li, Tobías I. Liaudat, Chengliang Wei, Peng Wei, Tianmeng Zhang, Hekun Li, Lei Wang, Han Qu, Zhaojun Yan, Nan Li, You Wu, Peng Jia
Instrumentation and Methods for Astrophysics · Cross-listed from astro-ph.EP
On-sky performance and prospects of near-infrared CMOS detectors in exoplanet detection: first year of SPIRIT
Clàudia Janó-Muñoz, Matthew J. Hooton, Peter P. Pedersen et al. (+8 more)
Ultracool dwarfs are promising targets for detecting and characterising temperate terrestrial
exoplanets. Their flux peaks in the near-infrared, beyond the wavelength cut-off of the silicon-based CCDs used by ground-based surveys dedicated to observing them, such as SPECULOOS. We present the on-sky performance of SPIRIT (SPeculoos InfraRed Imager for Transits), an InGaAs CMOS detector on the Callisto
telescope at the SPECULOOS Southern Observatory, during its first year of operation, from mid-2022 to 2023. We use 328 visits of 73 targets to optimise our CMOS-specific reduction process, including our approach to glow effects and bad-pixel handling. We find the measured precision to be consistent with our theoretical noise model, achieving sub-part-per-thousand precision under good observing conditions across targets spanning $J$-band magnitudes of 10–13. We further illustrate SPIRIT's capabilities with two case studies: a simultaneous SPIRIT $zYJ$ and CCD $I + z$ observation of a TRAPPIST-1\,h transit, and monitoring observations of the fast-rotating dwarf LP~944-20. Our results confirm that InGaAs infrared CMOS detectors are a cost-effective and competitive technology for ground-based transit photometry of cool
stars, and that they show promising prospects to become a core part of the next generation of instruments.
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All authors Clàudia Janó-Muñoz, Matthew J. Hooton, Peter P. Pedersen, Didier Queloz, Khalid Barkaoui, Yasmin T. Davis, Michaël Gillon, Benjamin V. Rackham, Mathilde Timmermans, Amaury H. M. J. Triaud, Sebastián Zúñiga-Fernández
Instrumentation and Methods for Astrophysics · Cross-listed from astro-ph.EP
LiDO: The Large inclination Distant Objects Survey
Mike Alexandersen, Rosemary E. Pike, Ying-Tung Chen et al. (+20 more)
Previous trans-Neptunian objects (TNOs) discovery surveys targeted the ecliptic plane, where the overall highest density is seen. High-inclination objects spend little time near the plane, and are thus under-represented in previous TNO surveys. The Large inclination Distant Objects (LiDO) survey targets these high-inclination populations in 34 sq.deg., located in two blocks 14-21 degrees north and south of the ecliptic plane, finding 148 objects, all with i>14 degrees due to survey design. A careful characterization of detection efficiency and other survey parameters results in a "characterized sample" of 125 objects detected within the survey's magnitude and rate limits, thus suitable for model comparison via survey simulations. LiDO detected 62 TNOs classified as resonant, including 21 Plutinos, of which 12 are securely Kozai resonators (always coming to pericenter off-ecliptic), as well as 9 objects in the 5:2 resonance, and several mixed mode inclination-eccentricity resonators. No objects beyond 63 au were detected, despite sensitivity to objects as far as 150 au. We found that the i>14 degree orbital distribution of the previous model from OSSOS was rejectable with the inclusion of the 38 characterized hot classical TNOs from LiDO. We constructed a proof-of-concept orbital distribution model of hot classical TNOs based on long-term stability sculpting, which is statistically acceptable for the LiDO and OSSOS samples, while producing population estimates (21,000$^{+3000}_{-3000}$ hot classicals with H_r<8.3) consistent with OSSOS estimates. The discovery of 125 characterized mid-to-high inclination objects in a variety of orbital classifications provides useful constraints for population modeling and the migration history of the Solar System.
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All authors Mike Alexandersen, Rosemary E. Pike, Ying-Tung Chen, Samantha M. Lawler, Mark Comte, Lowell Peltier, J. J. Kavelaars, Kathryn Volk, Cameron Semenchuck, Cameron Collyer, Jaidyn Draper, Stephen Gwyn, Hermosillo Ruiz, Matthew J. Holman, Katrina Kianpoor, Cameron J. Morgan, Ruth Murray-Clay, Jonathan Pond, Benjamin Proudfoot, AbdulRahman Rabaa, Darin Ragozzine, Emily Rieger, Mriana Yadkoo
Instrumentation and Methods for Astrophysics · Cross-listed from astro-ph.CO
specwizard: A Public Python Framework for Creating Synthetic Absorption Spectra from Hydrodynamical Simulations
Andrés Arámburo-García, Tom Theuns, Joop Schaye et al. (+1 more)
We present specwizard, a publicly available modular Python package for generating synthetic absorption spectra from hydrodynamical simulations. The code combines atomic data from the National Institute of Standards and Technology database with ionisation fractions computed using the cloudy spectral synthesis code for multiple ionising backgrounds, enabling consistent modelling of bound–bound and bound–free absorption for resonant transitions of all ions. specwizard employs a column-density–conserving projection scheme, includes natural line broadening for the Lyman series, and offers optional treatments of instrumental resolution and noise for direct comparison with high-resolution
quasar spectra. As example applications of the code, we shoot sightlines through the eagle cosmological simulation to generate a z = 3.2 synthetic
quasar spectrum containing H i Lyman-series transitions, including damping wings and Lyman-limit absorption. Additionally, we compute metal-absorption lines probing the circumgalactic medium of simulated
galaxies, and investigate the correlated absorption of H i and Si iii. We demonstrate that specwizard applied to outputs from eagle accurately reproduces key observational diagnostics of the Lyman-alpha forest, including the
redshift evolution of the mean transmission, the transmission PDF and the transmission power spectrum. We take advantage of the fact that the eagle simulation also reproduces the measured
evolution of the temperature-density relation to infer the
evolution of the amplitude of the ionizing background, finding excellent agreement with recent theoretical models and measurements.
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All authors Andrés Arámburo-García, Tom Theuns, Joop Schaye, Alexey Boyarsky
Instrumentation and Methods for Astrophysics
Identifying Planetary Nebulae Candidates from IPHAS and VPHAS+ Surveys via YOLO Deep Learning Models
Titouan Sérandour, Anne-Laure Méalier, Bruno Colicchio et al. (+5 more)
We present a deep learning detection method capable of effectively identifying planetary nebulae (PNe) on IPHAS and VPHAS+ surveys. Our detection pipeline is based on the YOLO architecture and is adaptable to other
datasets. Using the HiPS system, we preprocess and augment the $r$, $i$, and $H{\alpha}$ bands to produce two red, green, and blue (RGB) image
datasets: (1) $640 \times 640$ px images at full resolution, and (2) $1 280 \times 1 280$ px images designed to capture extended objects up to $0.2$ deg. Images of $\sim 2600$ PNe are labelled using the HASH database. The loss function and evaluation metrics are adapted to the diffuse and low-contrast nature of PNe; a very low intersection over union (IoU) threshold ($1\%$) is used. A $k$-fold cross validation shows that the YOLOv12m model achieves an average precision of $0.979$ on the first
dataset. At a confidence threshold of $0.15$, it achieves a precision rate of $98.7\%$ and a recall rate of $97.4\%$. We deployed our system (on $1280 \times 1280$ images) on the full surveys' coverage ($\sim 3755$ deg$^2$), and present a preliminary analysis of the detection results. The system is robust against artifacts such as CCD corner defects and HiPS tile joints. Our convolutional-neural-network-based model achieved excellent results on the test set, comparable to-or exceeding-that of a recent Swin
Transformer approach. However, a challenge persists when applying deep learning models to extensive and densely populated Galactic fields: the development of an automated system that can effectively discriminate PNe from mimics that human experts are able to distinguish (e.g., H II regions). We outline possible improvements for future work.
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All authors Titouan Sérandour, Anne-Laure Méalier, Bruno Colicchio, Dominique Daniel, Philippe Gilberton, Philippe Oros, Thomas Boch, Djaffar Ould Abdeslam
Instrumentation and Methods for Astrophysics · Cross-listed from astro-ph.GA
Microcaustics: Fast GPU-Accelerated Dynamical Microlensing of Time-Dependent Extended Sources
Joshua Fagin, Connor Stone, James Hung-Hsu Chan et al. (+7 more)
Gravitational microlensing probes unresolved
quasar accretion disc structure and compact objects in lens
galaxies and is an important systematic in strong-lens time-delay cosmography. Most analyses use static microlensing map simulations because evolving individual microlenses and caustics is computationally prohibitive. We present Microcaustics, a GPU-accelerated Python package built on PyTorch for dynamical microlensing of time-dependent extended sources in strong gravitational lenses. It combines a local-exact/far-field deflection solver, source-directed lens-plane scouting with temporal reuse, and biquadratic inverse polygon mapping (IPM). GPU batching and fused Triton rasterization accelerate the calculation, while binary caustic labels track source-centred crossings. Across three simulated quadruply lensed
quasar systems, our package generates a 10-year, 147-frame multiband light curve in an amortized median of 0.68 s (0.88 s with labels) on a consumer GPU with a median light-curve RMSE of 0.35 mmag, while recovering every reference source-centred caustic crossing. At comparable map accuracy, the batched throughput is 780 times higher than that of a recent CUDA IPM implementation and extrapolates to a speedup of millions relative to classic GPU-D. We demonstrate that our IPM converges as $N_{\rm ray}^{-0.84}$, approaching the idealized $N_{\rm ray}^{-1}$ convergence rate of piecewise-affine IPM and improving upon the $N_{\rm ray}^{-1/2}$ inverse ray-shooting rate. We also introduce a GPU-resident general relativistic and reverberating
quasar source model and demonstrate our method with an evolving
supernova source. These advances make fully dynamical stellar fields practical for
Bayesian and simulation-based inference.
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All authors Joshua Fagin, Connor Stone, James Hung-Hsu Chan, Sophia Miskiewicz, Henry Best, Paras Sharma, Matthew O'Dowd, Laurence Perreault-Levasseur, Yashar Hezaveh, Simon Birrer
Instrumentation and Methods for Astrophysics
Development and characterization of a millimeter-wave circular polarization observation method using a quarter-wave plate with Simons Array
Kana Sakaguri, Darcy R. Barron, Yuji Chinone et al. (+17 more)
We have developed and demonstrated a method for measuring circular polarization at 90 GHz by combining a quarter-wave plate (QWP) and a continuously rotating half-wave plate (HWP). While many bolometric experiments at millimeter wavelengths focus on measuring linear polarization, observations of circular polarization in millimeter waves may open a new window into astrophysics and cosmology. We present a novel approach to circular-polarization search using linear-polarization-sensitive detectors by incorporating a QWP in the optics. The Simons Array was originally designed for precise linear polarization measurements, and we subsequently installed a QWP in front of the receiver targeting 90 GHz. The QWP converts incident circular polarization to linear polarization, allowing detection with our detectors. Laboratory measurements demonstrate a QWP conversion efficiency of 99.0%. We apply our method to observations of unpolarized and linearly polarized bright sources, Jupiter and Tau A. Using these observations, we establish the calibration and characterize the instrumental leakages relevant to circular polarization measurements. The measured polarization efficiency adopted for Stokes $V$ is $46\pm2$%, and the measured U-to-V leakage is $-11.7\pm5.1$%. We measure a circular polarization fraction of $V/I=0.78\pm0.42$% for Tau A, showing no significant detection and providing a consistency check of the calibration and systematic-uncertainty treatment. These results establish the instrument response model and calibration parameters used for the companion circular-polarization source search.
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All authors Kana Sakaguri, Darcy R. Barron, Yuji Chinone, Matthew Ryan Chu, Nicole Farias, Takuro Fujino, Masaya Hasegawa, Masashi Hazumi, Haruaki Hirose, Jennifer Ito, Oliver Jeong, Daisuke Kaneko, Brian Keating, Akito Kusaka, Adrian T. Lee, Lindsay Ng Lowry, Richard Plambeck, Shahed Shayan Arani, Praween Siritanasak, Satoru Takakura
Instrumentation and Methods for Astrophysics
Optimal Design of Shaped Pupil Lyot Coronagraph for China's Large Segmented Telescope
Kaining Yang, He Sun, Bin B. Ren et al. (+7 more)
China's next-generation large
telescopes, such as the Expandable Aperture Segmented
Telescope (EAST) and the Large Optical/Infrared
Telescope (LOT), are being planned as flagship facilities for high-angular-resolution astronomy, including the direct imaging and characterization of exoplanetary systems (e.g.,
exoplanets, circumstellar disks). However, their segmented, centrally obscured apertures present significant challenges for coronagraph design: diffraction from segmented gaps and spiders severely limit contrast, particularly at small inner working angles (IWAs). To address this, we investigate an optimal Shaped Pupil Lyot Coronagraph (SPLC) architecture tailored for these
telescopes, which combines a binary shaped pupil apodizer, a focal-plane occulting mask, and a Lyot stop to suppress stellar glare and enhance contrast. We further augment the coronagraph design with a two-deformable-mirror (2-DM) adaptive optics (AO) system to correct atmospheric
turbulence and residual aberrations. End-to-end simulations based on site parameters for Lenghu in Qinghai Province and assuming idealized extreme AO (ExAO) correction demonstrate that the optimized 2DM-SPLC designs can achieve raw contrasts of order 10^-6-10^-7 in the V, H, and K bands, providing an upper-bound estimate of the system performance. The simulated performance highlights the advantages of the SPLC in mitigating diffraction from segmented and centrally obscured pupils while maintaining a small IWA and practical throughput, indicating that the 2DM-SPLC is a promising coronagraphic architecture for high-contrast
exoplanet imaging on China's future large segmented
telescopes.
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All authors Kaining Yang, He Sun, Bin B. Ren, Fabo Feng, Yiyun Wu, Jinxin Liu, Linbo Cao, Ruobing Dong, Feng Long, Wei Wang