Peer Revenue Publish or profit

Papers

Fresh from arXiv, typeset properly. Highlighted words trade on the market.

Physics Astrophysics Instrumentation and Methods for Astrophysics

astro-ph.IM Watch Instrumentation and Methods for Astrophysics

Friday 28 August

Instrumentation and Methods for Astrophysics

Fast and efficient nested sampling with BEST

Andreas Nygaard

Nested sampling is widely used for Bayesian evidence computation, but its intrinsically sequential structure limits how efficiently it can exploit modern vectorised likelihoods and emulators. We present a new nested-sampling implementation in best, written entirely in TensorFlow and designed for efficient XLA compilation on both CPUs and GPUs. The sampler combines clustering and slice sampling with the possibility of updating several live points simultaneously. Since batching breaks the strict ordering of conventional nested sampling, we introduce sorting and history-based corrections to reduce the resulting bias in the evidence estimate. We test the sampler on Gaussian, Rosenbrock, and multimodal likelihoods and compare its performance with JAXNS and UltraNest. The results show that accurate evidence estimates can be retained for moderate batch sizes, with $m/N_{\rm live}\lesssim 0.1$ providing a useful practical regime. Finally, using a 27-dimensional cosmological likelihood emulator, we show that batched live-point updates can substantially reduce the wall-clock time while remaining consistent with sequential sampling within the reported uncertainties. The new implementation therefore extends best with an efficient nested-sampling method tailored to fast, vectorised likelihoods and emulator-based inference.
Read the full abstract

Instrumentation and Methods for Astrophysics

pyEDITH: the coronagraphic exposure time calculator for the Habitable Worlds Observatory

Eleonora Alei, Miles H. Currie, Corey Spohn et al. (+7 more)

To support the development of next-generation missions for the search and characterization of habitable planets, high-fidelity tools for astrophysical and instrumental noise simulations are needed. In this paper, we introduce pyEDITH, the Python-based coronagraphic exposure time calculator built for the next recommended NASA flagship mission, the Habitable Worlds Observatory (HWO), tasked with searching for signs of habitability and life in dozens of nearby exoplanet systems. pyEDITH is designed to simulate wavelength-dependent exposure times and signal-to-noise ratios (S/N) for synthetic HWO direct imaging observations, considering realistic engineering specifications and user-defined target information. Its modular architecture ensures flexibility as mission requirements evolve. pyEDITH enables a streamlined integration with modern astronomical workflows and was designed to be used by the scientific community at all skill levels for understanding the capabilities and limitations of different HWO architectures for exoplanet analyses. The code has been validated against existing exposure time calculators and released open-source on GitHub and Zenodo, as well as made accessible through a Graphical User Interface. The pyEDITH package includes API documentation, tutorial notebooks, and has been used in forthcoming scientific publications.
Read the full abstract

All authors Eleonora Alei, Miles H. Currie, Corey Spohn, Christopher C. Stark, Aki Roberge, Avi M. Mandell, Enrico Biancalani, Samantha Gilbert-Janizek, Jacob Lustig-Yaeger, Sarah Steiger

Instrumentation and Methods for Astrophysics

JWST telemetry combined with active coronagraphy: raw contrast predictions for exoplanet imaging with the Habitable Worlds Observatory

Raphaël Pourcelot, Laurent A. Pueyo, Emiel H. Por et al. (+6 more)

We provide a quantification of the technological gap between the James Webb Space Telescope (JWST) and the Habitable Worlds Observatory (HWO) for the goal of exo-Earth imaging around Sun-like stars at the $10^{-10}$ raw contrast level. We use JWST's in-flight telemetry of the primary segmented mirror to simulate a JWST-like telescope equipped with a modern coronagraph instrument, inspired by the Roman Space Telescope (RST) Coronagraphic Instrument (CGI), featuring an Apodized Pupil Lyot Coronagraph and active deformable mirror wavefront control on a segmented, unobstructed, off-axis telescope. We show that it can achieve around $10^{-10}$ raw contrast for very bright stars (brighter than magnitude 4) for fast control frequencies of 100 Hz, but that this level of control still lacks sufficient signal to correct JWST-amplitude errors for fainter stars. We show that an improvement of a factor of ten in wavefront stability is sufficient to extend this capability to a $10^{-10}$ raw contrast across all considered control frequencies (1 Hz to 100 Hz), assuming no reaction wheel vibrations, for stars up to a magnitude of 11. These results establish a new quantitative benchmark linking JWST's demonstrated thermo-mechanical stability to HWO's requirements, showing that active wavefront control relaxes the structural stability demands on the observatory, and identifying wavefront stability as the critical technological gap that must be closed for HWO to achieve its exo-Earth imaging goals.
Read the full abstract

All authors Raphaël Pourcelot, Laurent A. Pueyo, Emiel H. Por, Marshall D. Perrin, Iva Laginja, Bryony Nickson, Sarah Steiger, Rémi Soummer, Rendal Telfer

Instrumentation and Methods for Astrophysics

Correction of the influence of rolling shutter detectors on determining the velocity of meteors from video recordings

Lukáš Shrbený, Jiří Borovička, Pavel Spurný et al. (+2 more)

Modern video cameras use either global or rolling shutter to create individual video frames. In case of global shutter, the whole frames are exposed and read out at the same time. In case of rolling shutter, the exposure and readout proceed sequentially line by line. Such cameras are now commonly used for meteor observations. It is then necessary to perform a correction for this type of image reading in order to correctly and accurately determine the velocity of recorded meteors. We provide here the correct procedure. The correction must include the value of the rolling period of the sensor, which is generally not provided in camera specifications. We discuss four methods of determining the rolling period experimentally. The most accurate method uses the New EXposure Timing Analyser (NEXTA) of [1]. We list rolling periods measured for several cameras.
Read the full abstract

All authors Lukáš Shrbený, Jiří Borovička, Pavel Spurný, Jan Mánek, Jan Fuchs

2608.28304 · 28 Aug · This preprint has not undergone peer review (when applicable) or any post-submission improvements or corrections. The Version of Record of this article is published in Experimental Astronomy, and is available online at https://doi.org/10.1007/s10686-026-10075-7

Abstract PDF $VID ×3

Instrumentation and Methods for Astrophysics

Development, Configuration and Performance Characterization of a Scalable BETA ASIC-Based Readout System for Multi-Channel SiPM Detectors

Giulio Lucchetta, Keerthana Rajan Lathika, Benjamin Nobre Hauptmann et al. (+17 more)

We present the design, configuration, and performance characterization of a scalable readout system based on the BETA application-specific integrated circuit (ASIC), developed to meet stringent requirements on noise, linearity, dynamic range, and power consumption for multi-channel silicon photomultiplier (SiPM) detectors in spaceborne instrumentation. The readout electronics consists of modular interface boards (FIBs) hosting multiple BETA ASICs and controlled by a field-programmable gate array (FPGA), which provides configuration, data acquisition, and global trigger generation. Multiple BETA FIBs were tested in a dedicated optical setup enabling simultaneous readout of a large number of channels. The system performance was evaluated using three S13552-10 SiPM arrays manufactured by Hamamatsu for the FIT detector, a scintillating-fiber tracker developed for charged cosmic-ray particle tracking and charge measurement in the HERD mission. We describe the configuration procedures and performance measurements of the readout system, including gain calibration, linearity characterization, and threshold response. In addition, we present the development of a global internal trigger logic for the identification of ionizing particles in the FIT detector. The results demonstrate the stability, scalability, and suitability of the developed BETA-based readout system for large-scale multi-channel SiPM detector applications in space experiments.
Read the full abstract

All authors Giulio Lucchetta, Keerthana Rajan Lathika, Benjamin Nobre Hauptmann, Philipp Azzarello, Oscar Blanch, Juan Boix, Laia Cardiel, Arturo Castaño Gallardo, Albert Espinya, Jennifer Maria Frieden, David Gascon, Daniel Gubermann, Kimberly Sarah Keyser, Manel Martinez, Joan Mauricio, Marina Orta-Terré, Chiara Perrina, Javier Rico, Andreu Sanuy, Monong Yu

Instrumentation and Methods for Astrophysics

The PLACID active coronagraphic imager instrument: commissioning status

Ruben Tandon, Lucas Marquis, Liurong Lin et al. (+9 more)

The world's first adaptive stellar coronagraph, the Programmable Liquid-crystal Active Coronagraphic Imager for the 4-m DAG telescope (PLACID) uses a spatial light modulator operating from H- to Ks-band to dynamically adjust the focal-plane phase mask entirely in software. Positioned between the TROIA XAO system and the DIRAC infrared detector, PLACID was installed on the Nasmyth platform of the Turkish 4-m DAG telescope in 2025, followed by optical alignment and successful preliminary acceptance tests with the calibration light source in early 2026. On-sky commissioning is expected, as soon as the TROIA XAO system will be operational. When on-sky, it will enable high-contrast imaging of exoplanets, brown dwarfs, disks, and binary systems, being able to easily deploy any desired phase pattern in the focal plane. Upcoming features include self-calibration of non-common path aberrations, coronagraphic nulling of binary-stars, and coherent differential imaging. We present the preliminary acceptance procedures and internal alignment results, discovery-space estimates, new binary star features and observation tools, to be ready for first science by late 2026/early 2027.
Read the full abstract

All authors Ruben Tandon, Lucas Marquis, Liurong Lin, Derya Öztürk Çetni, Axel Potier, Audrey Baur, Iljadin Manurung, Matthias Brändli, Martin Rieder, Daniele Piazza, Laurent Jolissaint, Jonas G. Kühn

Instrumentation and Methods for Astrophysics

Design and implementation of an SLM-driven coherent differential imaging scheme

L. Lin, L. Marquis, R. Tandon et al. (+1 more)

Direct imaging of exoplanets from the ground remains fundamentally limited by fast-evolving post-adaptive optics (AO) residual wavefront errors, and by quasi-static speckles arising from non-common path aberrations (NCPAs) downstream of the AO wavefront sensor. To first order, both sources of contrast degradation remain coherent with the stellar light, and recent studies have shown that coherent differential imaging (CDI) techniques can address their quasi-static and slowly evolving components. Recent laboratory demonstrations using focal plane phase diversity with an active LCoS spatial light modulator (SLM) have further established that local phase modulation can distinguish coherent speckles from incoherent astrophysical signals. Here we present a framework for the design and implementation of an SLM-based CDI integrator. Through simulations, we study the effects of varying the number of phase steps, modulation ring width, planet separation, and planet-to-star contrast. The numerical results are further supported by an initial laboratory validation. In the future, with the emergence of ultra-low-noise fast near-infrared detectors such as avalanche photodiode and microwave kinetic inductance detector (MKID) arrays, time-domain focal-plane CDI detection schemes could potentially also be able to suppress rapidly varying post-AO residual wavefront errors.
Read the full abstract

All authors L. Lin, L. Marquis, R. Tandon, J. Kühn

Instrumentation and Methods for Astrophysics · Cross-listed from physics.comp-ph

Promoting Green Computing in High Energy Physics and Astrophysics

Vasiliki A. Mitsou, Andreas Redelbach and Eleni Vardoulaki

This research topic aims to explore and promote strategies for green computing in high-energy physics and astrophysics. The primary objectives include assessing current energy consumption patterns, identifying opportunities for resource optimization, and fostering cross-disciplinary collaborations to enhance sustainability. Key questions to be addressed include: What are the current energy demands in these fields? How can existing technologies be leveraged for more efficient resource usage? What synergies can be identified between high-energy and astrophysics projects to promote green computing?
Read the full abstract

Instrumentation and Methods for Astrophysics

The Canadian Galactic Emission Mapper: A New 8-10 GHz Telescope to Map the Polarization of the Northern Sky

Joshua MacEachern, Mandana Amiri, Charles L. Bennett et al. (+12 more)

The Canadian Galactic Emission Mapper (CGEM) radio telescope is mapping polarized Galactic foregrounds from 8-10 GHz to aid in the search for B-modes in the Cosmic Microwave Background (CMB). Here we describe the design and early on-sky characterization of the CGEM optics. CGEM employs an on-axis, hat feed optical design that is a body of revolution (BOR) and exhibits excellent intrinsic polarization purity. We describe how we have optimized the optics with a novel framework that can directly minimize simulated intensity to polarized intensity ($T\rightarrow P$) leakage in angular power spectrum space. The optimized optics exhibit simulated $T\rightarrow P$ leakage that is orders of magnitude below anticipated $C_\ell^{BB}$ for $r = 10^{-3}$ when scaled from 8-10 GHz to the CMB observing window near 95 GHz. We go on to describe the mechanical design of the optics, including a novel secondary mirror support made from Astroquartz composite that has low loss, low dielectric constant, and preserves the BOR symmetry of the optics. We then showcase the early on-sky performance of the optics with observations of the Sun and satellites, which probe the beam to 40 dB down from the peak. A beam model for the deployed CGEM optics based on electromagnetic simulations is in excellent agreement with the on-sky data.
Read the full abstract

All authors Joshua MacEachern, Mandana Amiri, Charles L. Bennett, Guinevere Berg, Mark Halpern, Gary Hinshaw, Gordon Lacy, Thomas J. Rennie, Shuyu van Kerkwijk, Bruce Veidt, Pedro Villalba-González, Janet Weiland, Don Wiebe, Edward J. Wollack, Parham Zarei

Instrumentation and Methods for Astrophysics

Broadband heterodyne interferometry with a chirped femtosecond laser in the H-band

Félix Gudin and Nicolas Forget

Infrared heterodyne interferometry offers a scalable alternative to direct interferometry for long-baseline telescope arrays. However, at near-infrared wavelengths, its sensitivity is limited by the electronic detection bandwidth and shot noise from the optical reference. Parallel detection via spectral multiplexing has long been identified as a potential means to increase the signal-to-noise ratio of heterodyne interferometers. We propose a new heterodyne detection architecture based on highly dispersed broadband pulses from a mode-locked laser, fast photoreceivers, and numerical correlation. This enables straightforward spectral multiplexing with commercial components to increase the SNR, while extending instantaneous wavelength coverage to simultaneous J- and H-band operation. The scheme also supports high-resolution spectroscopic imaging ($R \simeq 10^{3}-10^{4}$). We derive the SNR of a two-arm heterodyne interferometer based on balanced photodetection and apply the model to the proposed scheme, using measurements from a single-spectral-channel, all-fiber interferometer operating at 1.56 micrometer over an 8 nanometer bandwidth. We experimentally demonstrate an SNR exceeding 2 for a spectral flux density of 188 pW/nm, with an integration time of 0.4 ms. Scaling the integration time and number of spectral channels suggests that fringe visibility of the brightest H-band stars could be achieved with 1 m$^2$ telescopes within the typical atmospheric coherence time. These results represent a significant step toward broadband, scalable heterodyne interferometers, demonstrating the potential of ultrafast laser and telecommunications technologies for astronomical interferometry in the J+H bands. By combining broadband spectral multiplexing with numerical correlation, the architecture also opens a route to direct spectro-imaging without an additional spectrometer.
Read the full abstract

Instrumentation and Methods for Astrophysics · Cross-listed from hep-ph

Future of Artificial Intelligence for Science in Japan 2024 Community Report

Yoshitaka Itow, Jia Liu, Hirokazu Maesaka et al. (+16 more)

This white paper summarizes scientific challenges and AI/ML research opportunities identified through the FAIRS Japan 2024 unconference process. The discussion focuses on three major physics domains: accelerator physics, cosmology and astrophysics, and neutrino physics. Although each domain has distinct scientific goals and experimental constraints, several common technical themes emerge: high-dimensional reconstruction, fast and accurate simulation, uncertainty propagation, simulation-to-data mismatch, anomaly detection, real-time decision-making, and shared infrastructure.
Read the full abstract

All authors Yoshitaka Itow, Jia Liu, Hirokazu Maesaka, Vinicius Mikuni, Nhat-Minh Nguyen, Hironao Miyatake, Atsushi J. Nishizawa, Patrick de Perio, Daniel Ratner, Kazuhiro Terao, Leander Thiele, Omar Alterkait, Francois Drielsma, Rocio Garcia, Masako Iwasaki, Ahsani Hafizhu Shali, Federica Tarsitano, Takahiro Terada, Junjie Xia

Thursday 27 August

Instrumentation and Methods for Astrophysics

JUG: JAX-based Unified pulsar timinG

Matthew T. Miles, Stephen R. Taylor, Matthew Bailes et al. (+14 more)

We present JUG (JAX-based Unified pulsar timinG), a JAX-based, fully independent pulsar timing package emphasising speed and ease of use, designed to confidently handle the increasingly large and complex pulsar timing array datasets that are being created in the pulsar timing field. JUG implements the entire pulsar timing pipeline itself, from data handling and clock corrections through to the timing model and fitting, without relying on other timing software. It enables Pythonic programming at the speed of compiled code, is GPU-capable, and can be operated via a Python API or an interactive GUI. A user of JUG can interactively explore data, fit timing models with complex stochastic noise, model deterministic signals such as continuous gravitational waves, and obtain accurate point estimates of the parameters of the stochastic processes present, thereby bridging frequentist timing and Bayesian noise analysis. JUG is faster than PINT by more than fifty times and is comparably fast to Tempo2, can handle millions of arrival times, agrees with PINT at the picosecond level, and can reliably recover known timing model and noise parameter values. In this paper we describe its design, performance, and validation, and demonstrate its advantages for pulsar timing data analysis.
Read the full abstract

All authors Matthew T. Miles, Stephen R. Taylor, Matthew Bailes, Aurelien Chalumeau, H. Thankful Cromartie, Kyle A. Gersbach, Rutger van Haasteren, Michael J. Keith, Nima Laal, Michael T. Lam, Kuo Liu, Aditya Parthasarathy, Scott M. Ransom, Daniel J. Reardon, Ryan M. Shannon, David C. Wright, Andrew Zic

Instrumentation and Methods for Astrophysics

PolPy: A universal tool for X-ray/gamma-ray polarimetry using common data format standards

Sujay Mate, Hancheng Li, Utkarsh Pathak et al. (+4 more)

X-ray/gamma-ray polarimetry has been a rapidly developing field in recent years. However, the lack of standardized analysis frameworks has hindered cross-instrument comparisons and joint multi-mission studies. To address this, we present PolPy, a universal tool designed for polarimetry of high-energy astrophysical transients. Built as a plugin for the Multi-Mission Maximum Likelihood (3ML) framework, PolPy introduces standardized data and response formats, common reference frames based on IAU conventions for defining polarization angles, and a robust likelihood-based template-matching algorithm. The article briefly describes these standards and presents tests and results performed to validate the software using simulated gamma-ray burst (GRB) injections across two different mission mass models: POLAR and Daksha. Our verification tests demonstrate that PolPy accurately recovers the injected polarization angles and fractions without systematic bias. Furthermore, we show that performing simultaneous joint fits across multiple detectors and instruments can significantly improve parameter constraints compared to single-instrument analyses. By unifying data formats and methodology, PolPy enables reliable joint polarimetric analysis for current and future high-energy polarimeters.
Read the full abstract

All authors Sujay Mate, Hancheng Li, Utkarsh Pathak, Yashowardhan Rai, Nicolas De Angelis, Varun Bhalerao, Merlin Kole

Instrumentation and Methods for Astrophysics · Cross-listed from eess.SY

Horizon-Dependent Tube MPC for Elliptical-Orbit Rendezvous Under Mass Uncertainty

Omer Burak Iskender and Keck-Voon Ling

A spacecraft closing on a target from three hundred kilometres to contact flies one guidance law across five orders of magnitude of range, and a controller that is provably safe at close range can lose that guarantee completely at long range while continuing to fly as though nothing were wrong. This paper derives the range at which the guarantee lapses and uses it as a design rule. The bound compares the prediction model's own linearisation error against the disturbance set the controller was built to reject, and needs only the sampling period, the orbit and that disturbance bound, so it can be evaluated before any simulation. On a Mars Sample Return approach it disqualifies the homing phase, where most of the propellant is spent, and clears the other two. Re-posing the disqualified phase in relative orbital elements restores the guarantee; re-posing a phase the rule already clears, in a frame two orders of magnitude more accurate, changes propellant by under a tenth of one per cent, and it is that second prediction that makes the rule falsifiable rather than descriptive. The constraint tightening also ties the prediction horizon to feasibility, so the horizon search limit becomes a mission parameter rather than a solver setting. Against a reimplementation of a published benchmark that reproduces its propellant to within one per cent, over five hundred dispersed Monte Carlo transfers per case on matched seeds, the controller saves 29% of the propellant on a circular target orbit and 40% on an eccentric one, docking inside the 0.20 m capture requirement on essentially every draw at a median miss near 5 cm. Two results run the other way: the saving is bought with time of flight and computation, and it comes from what the guarantee demanded of the terminal condition rather than from better disturbance rejection. Recursive feasibility and asymptotic stability are not claimed.
Read the full abstract

2608.27659 · 27 Aug · 19 pages, 12 figures, 8 tables. Accepted for presentation at the 77th International Astronautical Congress (IAC 2026), Antalya, Turkiye, 5-9 October 2026; paper IAC-26,C1,4,9,x108305. Accepted version (authors' preprint), not the version of record. Typeset in a plain article class rather than the IAF conference template

Abstract PDF $BNCH ×1

Instrumentation and Methods for Astrophysics

Toward a realistic test of black-hole movie correlations as a probe of extreme lensing

Barbora Bezděková and Shahar Hadar

In an optically thin setting, gravitational lensing around a black hole creates multiple delayed images of any localized source, appearing at different positions on the observer's screen. Even if particular sources cannot be singled out, this effect may be revealed in a black-hole movie (time-dependent image) by examining the two-point spatiotemporal correlation function of intensity fluctuations in the movie. Recently, the correlation function derived from a movie obtained by ray tracing of a general-relativistic magnetohydrodynamic simulation demonstrated the plausibility of this idea, even when the movie was blurred to angular resolutions corresponding to next-generation terrestrial very-long-baseline interferometric arrays. In this work, we further develop this method and study how some possible corruptions of the movie, motivated by real observational limitations, affect the ability to identify the extreme-lensing signatures by correlations. The effects are compared for both the original and blurred movies. We discuss the implications of our analysis for upcoming observations of M87* and Sgr A*, the two main targets of the Event Horizon Telescope and its future extensions. Our case study suggests that the types of data corruption we have explored, in themselves, do not preclude an identification of extreme-lensing effects in correlation measurements. We use our results to roughly estimate that, most importantly, for a successful correlation measurement, M87* may need to be continuously monitored for $\gtrsim 2$ years, while Sgr A* may need to be measured at a cadence $\gtrsim 1$ frame per minute. Finally, we outline a new analysis method that reduces the data in the complete correlation function—a large dataset defined on a five-dimensional configuration space—to a two-dimensional histogram that could be useful for black-hole parameter inference.
Read the full abstract

Instrumentation and Methods for Astrophysics · Cross-listed from astro-ph.GA

Measuring Extragalactic Microlens Masses and Motions in Strongly Lensed Quasar Systems with Intensity Interferometry

Abigail Moran and Ken Van Tilburg

The direct measurement of masses and transverse motions of individual stars and compact objects in distant galaxies remains an outstanding challenge, leaving extragalactic stellar populations constrained only through model-dependent population fits. We show that time-resolved intensity interferometry of strongly lensed quasars, combined with flux-ratio photometry, can break the source-size, microlens-mass, and transverse-velocity degeneracies of conventional light-curve microlensing. Using the quadruply lensed quasar B1422+231 as a fiducial system and a next-generation interferometer ($\sim$800\,m$^2$ collecting area, spectral resolving power of 20,000, and few-picosecond timing), we forecast the precision on the quasar source size and on the mass, position, and transverse motion of an individual stellar-mass microlens in the lens galaxy. A single epoch determines the accretion disk size to $4\%$ in favorable geometries ($10\%$ for a typical detectable configuration) and the microlens mass to order unity for $m_l \gtrsim 0.1\,M_\odot$. An eight-year, 33-epoch campaign reaches $\lesssim1\%$ on the disk size, localizes the microlens' impact parameter to $\sim0.1$-$0.5,\mu\mathrm{as}$, and resolves its proper motion. Such observations would enable direct measurements of individual extragalactic compact-object masses and transverse motions at moderate redshift. They also yield sub-$\mu\mathrm{as}\,\mathrm{yr}^{-2}$ sensitivity to light-centroid acceleration, which can help separate stellar microlensing from dark matter substructure lensing, the subject of a companion paper.
Read the full abstract

Instrumentation and Methods for Astrophysics

The MICADO first light imager for the ELT: first on-bench performance tests of the SCAO hybrid LQG+Integrator controller

N. Levraud, F. Ferreira, A. Sevin et al. (+6 more)

The Extremely Large Telecope (ELT) is expected to begin scientific operations in 2030, with MICADO as its first-light imager. The Single Conjugate Adaptive Optics (SCAO) system for MICADO is currently being assembled and tested at the Observatoire de Paris. MICADO's baseline AO control strategy uses a hybrid approach: a Linear Quadratic Gaussian (LQG) regulator for low-order modes, optimised to adapt to the disturbance caused by vibrations and ELT windshake, and an integral action controller for higher-oder modes. Despite the non linearity of the Pyramid Wavefront Sensor (PyWFS), the so-called "optical gains", LQG control has proven to be highly effective in simulation. It has been shown that the LQG regulator is resilient to optical gain variations in the loop or to inaccuracies in their estimation. Increasing the number of modes controlled by the LQG regulator would therefore make the controller less sensitive to the optical gains, which are notoriously difficult to estimate during operation. A first hybrid controller, with only tip-tilt controlled with LQG control, has been validated using COMPASS, the end-to-end, GPU-accelerated, AO simulation platform. We will present the first experimental validation of this hybrid controller on the MICADO-SCAO bench. We will also present results obtained by increasing the number of modes controlled with LQG control and the work carried out to go towards an autonomous LQG regulator.
Read the full abstract

All authors N. Levraud, F. Ferreira, A. Sevin, E. Gendron, N. Galland, H.-F. Raynaud, Y. Clénet, R. Davies, C. Kulcsár

Instrumentation and Methods for Astrophysics

Towards the exploration of astrophysical datacubes through volumetric rendering within CARTA

Ixaka Labadie-García, Adrianna Pińska, Angus Comrie et al. (+5 more)

Data products from astrophysical observations may contain three or more dimensions: most commonly two spatial dimensions and a third spectral dimension, and possibly additional axes such as polarisation or time. Visualising three-dimensional image data is particularly useful for analysing the kinematics and evolution of various objects; however, the large scale of data produced by next-generation observatories and the complexity of displaying 3D data on a 2D screen make visualisation challenging. In this article, we present a scalable and interactive 3D visualisation approach within the astronomy software CARTA. We implemented a prototype 3D rendering widget with ThreeJS and known techniques to improve efficiency (e.g. compression, downsampling) and found that large datacubes up to 128 GB can be visualised locally with a loading time of a few minutes. We analysed the performance in the frontend and in the backend, finding that the bottleneck of our implementation lies in the frontend. This is due to storing the data in a single array in the frontend, unlike in the backend, where it is accessed and sent in blocks. This study paves the way for making 3D visualisation of large datacubes available to the community by implementing a 3D rendering widget in a future release of CARTA.
Read the full abstract

All authors Ixaka Labadie-García, Adrianna Pińska, Angus Comrie, Michaela van Zyl, Manuel Parra-Royón, Susana Sánchez-Expósito, Lourdes Verdes-Montenegro, Julián Garrido

Instrumentation and Methods for Astrophysics

Optimal transport regularized dynamic radio interferometric reconstruction

Andy Nilipour, Kotaro Moriyama, Shiro Ikeda et al. (+2 more)

We propose a new technique for dynamic video reconstruction of radio interferometric data using the optimal transport (OT) distance as a regularizer within the regularized maximum likelihood (RML) framework. Compared to other commonly used regularization terms in RML and related prior-based approaches, the OT distance more naturally captures information including physical motion and promotes coherent dynamics. This property makes the OT regularization particularly suitable for dynamic imaging of astrophysical phenomena on minute timescales. We perform a series of tests on simulated very long baseline interferometric (VLBI) observations of Sagittarius A$^\ast$ (SgrA*), the supermassive black hole at the Galactic Center, with the Event Horizon Telescope (EHT), using both geometric and general relativistic magnetohydrodynamic models. We demonstrate that adding an OT regularization term yields significant improvements in dynamic reconstructions compared to those without it, as quantified by better recovery of orbital motion and higher dynamic cross-correlation metrics. Continued developments in OT theory across various fields, proposed extensions to the EHT network, and broad applicability to other VLBI networks make it so that OT regularization for dynamic radio interferometric reconstructions will continue to be utilized and improved in the future.
Read the full abstract

All authors Andy Nilipour, Kotaro Moriyama, Shiro Ikeda, Kazunori Akiyama, Mareki Honma

Instrumentation and Methods for Astrophysics · Cross-listed from astro-ph.EP

The true masses of radial-velocity exoplanets constrained by stability

Xander Byrne and Amy Bonsor

Exoplanets discovered with the radial velocity method suffer from a mass-inclination degeneracy: only the minimum mass $M_{\rm min} = M \sin i$ is measured. An exoplanet with an Earth-sized minimum mass could actually therefore be a sub-Neptune, or even a gas giant. However, for compact multi-planet systems, the inclination angle cannot be too low, as this would imply masses so large that the system would be dynamically unstable on time-scales shorter than the age of the system. We present CINEMAS, a Bayesian framework to constrain the inclinations - and hence true masses - of radial-velocity exoplanets in flat multi-planet systems, by accounting for dynamical stability. Applying this framework to five compact exoplanetary systems, we cut upper limits on the true masses of their planets by as much as 45%. As two examples, the masses of the four Barnard's Star planets are constrained to all be below $0.6~M_{\oplus}$ to at least 95% confidence; and the three gas giants orbiting HD 184010 are found to be intermediate in mass between Saturn and Jupiter. With only ~1% of planetary systems being inclined enough to transit, methods of studying non-transiting systems are vital for constraining the properties of nearby exoplanets.
Read the full abstract

Instrumentation and Methods for Astrophysics

Background Intensity Estimation for Cassini-ISS Image Using Deep Learning-Based Diffusion Model

Yongxin Chen, Qingfeng Zhang, Tianle Zhou et al. (+1 more)

Accurate background intensity estimation is crucial for precise astrometric measurements in astronomical imaging, particularly in complex scenarios such as those encountered in Cassini Imaging Science Subsystem (ISS) observations of Saturn's ring system. Traditional methods, like polynomial fitting and statistical method, often fail in non-uniform conditions, such as those caused by Saturn's rings or scattered light, due to mismatched assumptions and reliance on prior knowledge. This results in biased estimates and poor generalizability. We propose a deep learning framework based on Denoising Diffusion Probabilistic Model (DDPM) to address these challenges. By learning noise patterns and iteratively reconstructing backgrounds, DDPM improve background intensity estimation in ring-gap regions of ISS images by up to 62% relative to polynomial fitting. Additionally, When applied to centroiding of unresolved satellites in ring-gap, DDPM-based background estimation enhances positional precision by about 14% in the line direction and 15% in the sample direction. The framework autonomously captures spatial correlations, requires no manual parameter tuning, and generalizes across diverse backgrounds. These characteristics make it a promising, assumption-light solution for background estimation tasks in astrometry, photometry, and source detection, with potential applications to exoplanet transit imaging, deep-field surveys, and future missions.
Read the full abstract

All authors Yongxin Chen, Qingfeng Zhang, Tianle Zhou, Kai Tang

Wednesday 26 August

Instrumentation and Methods for Astrophysics · Cross-listed from physics.hist-ph

The Surviving Fragment of the Zij-i Malikshahi: A Preliminary Edition, Translation, and Study of the 100-Star Catalogue in BnF Arabe 5968

Rizoi Bakhromzod

The astronomical programme sponsored by the Saljuq Sultan Malikshah I in the late eleventh century occupies an important place in the history of Islamic astronomy. Umar Khayyam was a principal participant in this programme, which produced the Jalali or Maliki calendar and appears also to have resulted in a broader set of astronomical tables known as the Zij-i Malikshahi. A 100-star catalogue traditionally associated with these tables survives in the anonymous Arabic compendium Dustur al-munajjimin, preserved in the unique manuscript BnF Arabe 5968. This study distinguishes the catalogue from the Jalali calendar and from the lost or unidentified complete Zij-i Malikshahi, reconstructs its historical and manuscript context, and examines the provenance of BnF Arabe 5968. It presents a complete transcription of the catalogue from fols. 224r-225r and a new English translation made directly from the Arabic text, with B. A. Rosenfeld's 1961 Russian translation used as a control. The collation identifies several divergences, including a substantive correction to the longitude of entry 8, and clarifies the planetary temperament abbreviations. Rosenfeld and A. P. Yushkevich observed that 96 of the 100 stellar longitudes correspond to Ptolemaic values increased by about 14 degrees 26 minutes, while 87 latitudes agree with Ptolemy. These correspondences suggest systematic updating of inherited Ptolemaic data rather than 100 wholly independent observations, illustrating the combined roles of observation, computation, transmission, and adaptation in medieval Islamic astronomy.
Read the full abstract

Instrumentation and Methods for Astrophysics · Cross-listed from astro-ph.SR

Path to Black Hole Astrometric Microlensing from 10-Year KMTNet Database

Andrew Gould

I present a Fisher analysis of the astrometric signature of black holes (BHs) that may lie in the 10-year KMTNet microlensing database, motivated by the recent success of the pilot study by Segev et al. (2026), which reduced the scatter at $I=18$ to $\sigma\sim 10\,$mas. Seeing-limited ground-based observations still suffer from a great deal of systematics, but under the assumption that these systematics can be controlled, I find that with this nominal precision, the Einstein radius can be measured with errors $\sigma(\theta_{\rm E})\sim 0.5\,$mas in the most intensively monitored fields ($\sim 12\,$deg$^2$), and hence to twice that value in an additional $\sim 28\,$deg$^2$ area. This precision hardly depends on whether the peak of the event is during the observing season or not, as long as the impact parameter is within the broad range that is accessible to photometric recognition of the event, i.e., $u_0\lesssim 1.5$. However, longer events do have somewhat better precision. The analysis presented here ignores blending, but this is a good first approximation for most sources $I\lesssim 18$, which lie near or on the giant branch. I outline a practical program, combining photometric and astrometric searches, aimed at identifying isolated BHs in the KMTNet database and measuring their masses and distances.
Read the full abstract

Instrumentation and Methods for Astrophysics

Microscopy assessment of two multiple-transient candidates

Jun Yang and Beatriz Villarroel

We present a microscopy-based assessment of two representative cases of multiple-transient candidates identified on historical photographic plates: the nine-transient event of 12 April 1950 (XE325) and the triple-transient event of 19 July 1952 (XE186). These events consist of spatially clustered, point-like sources detected within single long-exposure plates, lacking the streaks expected from moving objects and therefore suggestive of short-duration flashes. We analyse microscopy images of the original glass-plate material together with an independent copy plate and archival metadata, and we register these images against the published survey digitizations so that individual catalogued sources can be located. In both cases the candidates appear slightly sharper and more compact than typical stellar point spread functions, qualitatively consistent with sub-second to few-second emission during exposures of $\sim 50$~min, and they are reproducible across different representations of the same field, which disfavours a digitization-artifact origin. However, microscopy of individual point-like features cannot by itself separate a short-duration flash from an intrinsic emulsion defect, because the two scenarios produce qualitatively similar signatures at the single-source level. We also show that the multi-observatory parallax test, while powerful in principle, is not feasible for these two specific events with presently available material, owing to the absence of a simultaneous second-site plate reaching comparable depth. We conclude that resolving the nature of these events requires population-level statistics and, where future observations allow, purpose-built multi-station imaging. This work provides a proof-of-concept framework for combining microscopy with archival analysis in the study of historical transient phenomena.
Read the full abstract

Instrumentation and Methods for Astrophysics · Cross-listed from astro-ph.CO

Cross-simulator transfer with foundation model summaries: Towards robust SKA-era reionization inference

Yannic Pietschke, Caroline Heneka, Ayodele Ore et al. (+1 more)

Simulation-based inference (SBI) for parameter estimation is vulnerable to model misspecification: neural summaries and density estimators trained on a specific forward model typically fail when applied to data drawn from another model, or from real observations, and no training simulator can capture the full observational pipeline of a real measurement exactly. We show that a self-supervised Vision Transformer (ViT), pretrained label-free on a fast approximate simulator, produces transferable data summaries that generalize across simulators. Without retraining, it can be reused as a frozen encoder to infer astrophysical parameters from a completely different simulator that resolves the radiative transfer explicitly, on which it has never seen either data or parameters. As a concrete use case in 21cm cosmology, SKATR, a ViT pretrained with a Joint Embedding Predictive Architecture (JEPA), serves as a foundation model for reionization inference from upcoming SKA measurements: SKATR is pretrained once on 67k low-cost, noiseless semi-numerical 21cmFAST lightcones, then frozen and applied to hydrodynamical Loreli II lightcones, where a lightweight conditional flow matching head infers five astrophysical parameters; the encoder is never shown Loreli data, its parameters, or any noise. In our comparison, SKATR yields the most precise and best-calibrated posteriors across all five parameters, matching the accuracy of the fully-supervised in-domain baseline while requiring 2.6x fewer radiative-transfer simulations. Under realistic SKA AA* noise, only SKATR remains simultaneously accurate, informative, and calibrated, outperforming even a supervised baseline retrained from scratch on noisy data. Self-supervised pretraining on computationally efficient semi-numerical simulations is therefore a viable route to calibrated, simulator- and noise-agnostic reionization inference for the SKA-era.
Read the full abstract

All authors Yannic Pietschke, Caroline Heneka, Ayodele Ore, Romain Meriot

Instrumentation and Methods for Astrophysics · Cross-listed from astro-ph.CO

HOLISMOKES – XVIII. Cosmology with strongly lensed type II supernovae: Effects of instrumental setups on $H_0$

J. Grupa, S. Taubenberger, S. H. Suyu et al. (+3 more)

The upcoming Rubin Observatory and subsequent follow-up observations should improve the determination of the Hubble constant ($H_0$) via time-delay cosmography of strongly lensed type II supernovae (LSNe II), by enabling the detection of many more such events. In our previous work, we developed a method for determining the supernova (SN) phase from spectral absorption features. Because obtaining spectra of faint targets such as distant SN II is expensive, we examined how low-resolution spectra influence the precision of time-delay retrieval, and consequently the precision on $H_0$. We considered spectral resolutions $R = \frac{\lambda}{\Delta \lambda}$ between 100 and 250, and we investigated three signal-to-noise ratio ($S/N$) values of 10, 15, and 20, for each resolution. Furthermore, we forecast the precision on $H_{0}$ achievable with $S/N=10$ and compared the observing time required to reach it with ground-based and space-based facilities. We find that the time delay can be determined without bias and with uncertainties as low as 1.3 days for the investigated resolutions and $S/N$ values when we combine time-delay measurements of multiple absorption lines. For a typical LSN II system (absolute magnitude $\sim-$17 mag in the rest-frame V band, source redshift of \zs = 0.8), the required exposure times range from multiple hours for ground-based observations to a few minutes for space-based observations with the JWST. Our predictions on the precision of $H_0$ for a single lensed SN range from 14.2% for $R = 100$ and $S/N$ = 10 to 7.5% for $R = 250$ and $S/N$ = 20, enabling a 1% determination of $H_0$ from $\sim$20 lensed SNe in the coming years.
Read the full abstract

All authors J. Grupa, S. Taubenberger, S. H. Suyu, D. Sluse, S. Huber, C. Vogl

Instrumentation and Methods for Astrophysics

RadialPaths: Radial profiles in multi-centred astronomical structures

Rafael S. de Souza

Radial profiles are routinely used to locate structural changes within resolved astronomical systems, but they generally define radial position relative to a single centre. In interacting, clumpy, or otherwise multi-centred structures, the radial location assigned to a feature can depend on the adopted centre. We introduce a centre-conditioned radial representation for connected structures with multiple centres. Distances are measured through the observed source footprint rather than across excluded background, and can be viewed as arrival times of fronts propagating from the centres. Each location is associated with the centre reached first and described by two complementary coordinates: relative centre–boundary depth and normalized progression away from that centre. For an ideal centred circular source, both reduce exactly to the familiar normalized radius $r/R$; in folded, elongated, or tailed geometries they separate because proximity to a lateral boundary and progression through the structure represent different notions of “outward”. Synthetic examples show that single-centre and equivalent-area radial descriptions do not retain the association between localized features and individual centres, whereas centre-conditioned profiles do. In two JADES DR2 systems, the resulting F277W profiles remain stable under modest changes in the adopted source footprint and one-pixel centre shifts. The construction assumes neither a light-profile law nor an overlapping flux decomposition, and the same radial geometry can be applied to registered maps of continuum light, colour, emission lines, stellar-population properties, and line-of-sight kinematics. An accompanying Python package, RadialPaths, provides the reference implementation together with documentation and online tutorials at \href{https://rafaelsdesouza.com.br/radialpaths} {GitHub}.
Read the full abstract

Instrumentation and Methods for Astrophysics

The MegaWave Radio Surveyor

T. Joseph W. Lazio, Evgenya Shkolnik, James Aguirre et al. (+40 more)

Several Decadal-level questions in astrophysics, exoplanets, astrobiology, and cosmology can be addressed only at low radio frequencies inaccessible from Earth. The MegaWave Radio Surveyor would open this largely-unexplored region of the electromagnetic spectrum with a space-based interferometer to (1)~Track the space weather of other stars; (2)~Detect magnetically-generated emission from exoplanets to probe their interiors and assess magnetic shielding of their atmospheres; (3)~Probe the Universe's evolution during the Dark Ages via the highly-redshifted HI hyperfine line; and (4)~Assess the role of cosmic rays and magnetic fields in the cosmic web. An Astrophysics Strategic Technology & Research Accelerator (ASTRA) Initiative concept, the MegaWave Radio Surveyor's science objectives respond to the Pathways to Discovery Decadal Survey and three other National Academies studies, and it would serve as a Formative Era mission in the Enduring Quests, Daring Visions roadmap. Developments in U.S. space industries enable this observatory to be realized. The MegaWave Radio Surveyor would offer a versatile, scalable, and resilient architecture capable of sensitive and simultaneous observations below 45~MHz and unprecedented angular resolution at these frequencies. The concept builds upon NASA's Sun Radio Interferometer Space Experiment (SunRISE), Star-Planet Activity Research CubeSat (SPARCS), and Lunar Surface Electromagnetics Experiment (LuSEE-Night). The MegaWave Radio Surveyor could leverage multiple elements of the Artemis program, such as access to and beyond cislunar space and communications, and there are opportunities to infuse new autonomy/AI modes for mission operations. By opening one of the last windows in the electromagnetic spectrum and pioneering space interferometry at unprecedented scales, the MegaWave Radio Surveyor would establish a transformational capability.
Read the full abstract

All authors T. Joseph W. Lazio, Evgenya Shkolnik, James Aguirre, Stuart D. Bale, Judd Bowman, Ruby Byrne, Joseph Callingham, Tracy E. Clarke, Ivey Davis, Tim Dolch, Peter Driscoll, Anastasia Fialkov, Steven Furlanetto, Simona Giacintucci, Ravit Helled, Jacqueline Hewitt, Phil Hopkins, Andrea Isella, Daniel Jacobs, Eloy de Lera Acedo, Melodie M. Kao, Mary Knapp, L.V.E. Koopmans, Nicholas Kern, Jasmina Lazendic-Galloway, Susan T. Lepri, R. O. Parke Loyd, James P. Lux, James P. Mason, Raul Monsalve, Miguel Morales, Julian B. Muñoz, Rachel Osten, J. Sebastian Pineda, Jonathan Pober, Sam B. Ponnada, Leslie A. Rogers, Saurabh Singh, Jake D. Turner, Jackie Villadsen, Philippe Zarka, John ZuHorne, Ellen Zweibel

Instrumentation and Methods for Astrophysics · Cross-listed from astro-ph.CO

Paleo-Detectors as a Novel Probe of Dark Matter-Nucleus Effective Interactions

Dionysios P. Theodosopoulos

Paleo-detectors are a proposed approach to the direct detection of dark matter (DM) based on the observation of DM-induced nuclear recoils. Rather than relying on large detector masses required for conventional detectors, paleo-detectors exploit extremely long integration times, using small samples of naturally occurring minerals that have resided deep underground and accumulated damage tracks over geological timescales of order a gigayear. In this contribution, we review recent theoretical predictions for the sensitivity of paleo-detectors to WIMP-nucleus interactions within the framework of a Non-Relativistic Effective Field Theory (NREFT). We discuss both elastic and inelastic scattering processes and consider isoscalar couplings, taking into account backgrounds from neutrinos and radiogenic sources. We present projected sensitivities of paleo-detectors for different readout and exposure scenarios and compare the reach of paleo-detectors to that of conventional direct-detection experiments. For DM masses in the range $1\ \mathrm{GeV}/c^2$-$10\ \mathrm{GeV}/c^2$, paleo-detectors are expected to achieve sensitivities exceeding those of conventional experiments for WIMP-nucleus interactions mediated by all NREFT operators, with only a weak dependence on the read-out scenario or target mineral. For larger DM masses, $10\ \mathrm{GeV}/c^2$-$5\ \mathrm{TeV}/c^2$, paleo-detectors are projected to attain sensitivities comparable to or surpassing conventional experiments for interactions mediated by several NREFT operators, depending on the specific read-out scenario and choice of target mineral.
Read the full abstract

Instrumentation and Methods for Astrophysics

Alfred: A Flexible, User-Friendly Python Package for Exoplanet Confirmation

Maxwell A. Kroft

In the era of TESS, exoplanet follow-up and confirmation have become a massive community effort. With only about an eighth of the over 8,000 TESS exoplanet candidates confirmed, astronomers need flexible software to allow them to characterize many different kinds of systems with data from multiple telescopes and instruments. In this work, I present Alfred (the Awesome Library For Robust Exoplanet Detection), an open-source Python package for exoplanet detection and confirmation. Alfred is designed to be flexible and easy to use, allowing users to fit transit and radial velocity data for an arbitrary system of exoplanets. The code is released under an MIT license on GitHub (https://github.com/maxkroft/Alfred ) and is installable via pip, with documentation under active development (https://alfred-exoplanets.readthedocs.io/en/latest/index.html# ).
Read the full abstract