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

Thursday 20 August

Instrumentation and Methods for Astrophysics

The SPT-3G+ receiver design

H. Athreya, Z. Ahmed, J. E. Austermann et al. (+71 more)

We present the thermo-mechanical design of the cryostat and camera optics for SPT-3G+, a new receiver being developed for the South Pole Telescope (SPT). The receiver consists of 14 detector arrays of 90/150 GHz dichroic polarization-sensitive pixels, totaling 24,080 transition-edge sensor detectors. Each detector array lies at the end of an optics tube, each approximately 240 mm in diameter and 772 mm in length, which are arranged in a hexagonal close-packed configuration to achieve a 4 degree diameter field of view. Each optics tube contains four anti-reflection coated lenses fabricated from different materials (alumina, silicon, and nylon) that are designed to also provide infrared filtering that reduces the radiative loading on the cryogenic stages. The optics and detectors are cooled by a combination of a pulse tube cooler for the 40 K and 4 K stages, and a dilution refrigerator for the 1 K and 100 mK stages. Thermal modeling predicts the heat load to be less than 26 W and 1 W for the 40 K and 4 K stages, respectively. The 1,550 kg cryostat has a 1.1 meter diameter at the vacuum window, which is located near the telescope Gregorian focus, and 1.75 meters in height and length. Fabrication of the cryostat will begin in 2026, with installation on the SPT scheduled for the 2028-29 austral summer, ahead of the 2029 winter observing season.
Read the full abstract

All authors H. Athreya, Z. Ahmed, J. E. Austermann, K. Bae, A. Bapat, D. R. Barron, P. S. Barry, A. N. Bender, B. A. Benson, L. E. Bleem, J. E. Carlstrom, T. W. Cecil, C. L. Chang, S. Cisneros, A. Coerver, J. Cornelison, R. Datta, K. R. Dibert, W. Dominguez, S. M. Duff, K. Fichman, J. P. Filippini, L. Gades, P. A. Gallardo, S. Galli, N. W. Halverson, Q. Hao, S. Henderson, R. Herbst, W. L. Holzapfel, A. Hryciuk, J. Hubmayr, D. Jones, V. Kabra, K. S. Karkare, C. King, M. A. Koc, A. M. Kofman, R. A. Lew, M. J. Link, T. J. Lucas, A. Mangu, E. S. Martsen, J. J. McMahon, J. Montgomery, J. M. Nagy, T. Natoli, H. Nguyen, V. Novosad, S. Padin, T. Pinsonneault-Marotte, S. Raghunathan, A. S. Rahlin, C. L. Reichardt, L. Ruckman, J. E. Ruhl, M. S. Sarwar, S. Simon, R. Singh, J. A. Sobrin, A. A. Stark, Q. Taylor, C. Tucker, J. Ullom, J. Van Lanen, J. D. Vieira, A. G. Vieregg, M. R. Vissers, G. Wang, W. L. K. Wu, V. Yefremenko, E. Yilmaz, C. Yu, J. Zivick

Instrumentation and Methods for Astrophysics · Cross-listed from gr-qc

Gravitational-wave parameter estimation with machine-learning generated surrogate waveforms

Suyog Garg and Kipp Cannon

The worldwide network of gravitational-wave detectors have detected more than 350 binary coalescence events till date. Future third-generation detectors, like Einstein telescope, are expected to detect orders-of-magnitude more signals from sources with more complicated characteristics, including eccentric orbits and high-mass ratio binaries. It is well-established that the computational cost of parameter estimation for signals from these kinds of sources will be extremely high. In particular, the process could be sped-up if generating theoretical waveform predictions, used for likelihood calculation becomes faster. Recently, various machine-learning techniques has been proposed to this end. In this work, we propose a two-stage deterministic conditional-autoencoder model for generating four-parameter SEOBNRv4 waveforms. The first-stage of the model generates amplitude and phase series of the waveform, while the second-stage calibrates the residual error in the predictions. Our model achieves a median mismatch of around $10^{-2}$ with the target polarization waveforms, while the calibrated amplitude/phase series achieve $10^{-6}$ level cosine distance error. We then propose a waveform conditioning step to enable use of these surrogate waveforms for downstream parameter estimation tasks. Finally, we perform extensive parameter estimation tests, with ML and EOB waveform injections and try to recover posterior estimates for the source parameters. We find that when ML waveforms are used to recover EOB target parameter estimates, the inferred posterior have some systematic bias. This inherent bias can be estimated and corrected for, and then importance reweighting of posterior samples can enable use of low-accuracy surrogate waveforms at low SNRs.
Read the full abstract

Instrumentation and Methods for Astrophysics

A dual-polarization whitened-template trigger for real-time radio detection of extensive air showers

Qader Dorosti, Alperen Aksoy, Ilja Bekman et al. (+7 more)

Autonomous radio stations require a first-stage trigger that rejects measured background while preserving weak extensive-air-shower pulses under tight hardware constraints. We present a dual-polarization trigger based on a 16-sample whitened pulse template evaluated continuously on the orthogonal north-south and east-west channels of an Auger Engineering Radio Array station. The template is derived from detector-folded air-shower pulses and whitened using the covariance of measured background. Responses from both polarizations are combined within a fixed timing radius and compared with a calibrated threshold. On an independent test set, the trigger reaches an efficiency of 0.97, with a 95 percent confidence interval of 0.96 to 0.98, at a frame-equivalent candidate rate of 3.39 kHz. At the same operating point, an unwhitened dual-polarization template reaches 0.41 efficiency and an amplitude trigger reaches 0.16. Efficiency remains at least 0.94 in every populated signal-to-noise bin. Replay of 159.29 ms of continuous measured background yields a score-cluster rate of 6.64 kHz, below the 71.4 kHz capacity of the downstream module. The FPGA implementation accepts one dual-polarization sample per clock, closes timing at 200 MHz, and uses 2377 lookup tables, 5330 registers, and 32 digital signal-processing blocks. Register-transfer-level simulation agrees bit for bit with the reference implementation for 400 traces. These results show that background covariance, pulse morphology, and dual-polarization consistency can be combined in a compact real-time radio trigger.
Read the full abstract

All authors Qader Dorosti, Alperen Aksoy, Ilja Bekman, Markus Cristinziani, Eric-Teunis de Boone, Vesselin Dimitrov, Chimezie Eguzo, Stefan Heidbrink, Stefan van Waasen, Andre Zambanini

Instrumentation and Methods for Astrophysics

Towards independent event horizon imaging of the supermassive black holes in M87 and the Milky Way

Nithyanandan Thyagarajan, Samuel Lai, Ivy Wong et al. (+1 more)

The Event Horizon Telescope (EHT) Collaboration's images of the supermassive black holes in M87 and the Milky Way have provided the first event-horizon-scale views of these objects, opening new avenues for studies of gravitation, accretion physics, and black hole astrophysics. Achieving these results, however, requires imaging under some of the most challenging conditions in radio astronomy, including low signal-to-noise ratios, severe calibration uncertainties, and sparse aperture coverage. With the aim of presenting independent analyses of the public EHT datasets for M87* and Sgr A*, we adopt an approach that is independent in observables, and reconstruction methodology. Our framework is based on closure invariants, a class of interferometric observables that are intrinsically immune to station-based calibration errors and therefore provide robust constraints on source structure. We combine these observables with Generative Deep learning Image Reconstruction with Closure Terms (GenDIReCT), a diffusion-based image reconstruction framework that operates in the latent space of images conditioned on closure invariants. We present independent reconstructions obtained using GenDIReCT on synthetic challenge data sets as well as real EHT data on 3C279 and Centaurus A, and compare them with previously reported results. This work demonstrates the potential of closure-invariant-driven generative imaging as a calibration-resilient framework for Very Long Baseline Interferometry (VLBI) and provides an independent and complementary avenue for interpreting horizon-scale black hole observations.
Read the full abstract

All authors Nithyanandan Thyagarajan, Samuel Lai, Ivy Wong, Foivos Diakogiannis

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

Diffractive-Sail Single-Impulse Reachable Set for Interplanetary Transfer Design

Shuyue Fu, Jinkai Zhang, Di Wu et al. (+2 more)

Interest in planetary exploration has renewed, and the design of interplanetary transfers has attracted remarkable attention. This paper considers the interplanetary transfer design using a diffractive sail. Considering a nonzero departure hyperbolic excess velocity, the interplanetary transfer problem is transformed into the problem of computing single-impulse reachable sets. Then, based on previous work, a complementary computational method for reachable sets under arbitrary dynamics is proposed using differential algebra combined with adaptive grid refinement. The adaptive grid refinement considers two types of merit scores that reveal dynamical properties and the truncation error of the differential algebra propagation. The proposed method is applied to compute the diffractive-sail reachable sets, and the results verify the effectiveness of the method and merit scores. Finally, a preliminary design of the interplanetary transfers, specified as the Earth-Mars transfers, is performed based on the diffractive-sail reachable sets. The design results are presented. The effects of the corresponding parameters, including transfer time, diffractive angle, and type of diffractive sails, on transfer characteristics are analyzed, providing further insight into parameter selection for interplanetary transfer design.
Read the full abstract

All authors Shuyue Fu, Jinkai Zhang, Di Wu, Peng Shi, Shengping Gong

Wednesday 19 August

Instrumentation and Methods for Astrophysics

Fast Control for LIGO Interferometer Lock Acquisition

Masaya Ono, Nathan A. Holand, Radhika Bhatt et al. (+4 more)

Gravitational wave observatories are large scale laser interferometers which are held on resonance to facilitate the detection of gravitational waves. Achieving this resonant condition is a time consuming process, and in the LIGO gravitational-wave observatories this procedure has a relatively low success rate. This limitation leads to a loss of observation time thereby reducing the number of observable astrophysical events. The primary cause of this problem is the coupling among the longitudinal degrees of freedom of the interferometer, particularly the coupling from the arm cavity lengths to the central degrees of freedom, such as the recycling cavities and the Michelson interferometer. We demonstrate a simpler and faster lock acquisition scheme at the 40-meter prototype interferometer, located at the California Institute of Technology. This scheme is achieved by controlling the arm cavity lengths with high bandwidth during the lock acquisition process. In this paper, we describe how this fast lock acquisition is realized, compare it with the current LIGO lock acquisition method, and discuss how our framework can be implemented in LIGO.
Read the full abstract

All authors Masaya Ono, Nathan A. Holand, Radhika Bhatt, Peter G. Carney, Francisco Salces Càrcoba, Koji Arai, Rana X. Adhikari

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

Finding Habitable Exoplanets with Binary Relative Astrometry: Planet Detection and Characterization with the Microarcsecond Astrometric Retrieval Algorithm (MARA)

William Roberson, Eric L. Nielsen, Jessie L. Christiansen et al. (+8 more)

Binary relative astrometry is a technique to search for rocky planets in the habitable zone of nearby binary stars using 1D relative astrometry at the microarcsecond level. This unprecedented precision would allow a custom-designed space telescope to directly measure the occurrence rate of these planets. The success of such a mission depends on our ability to recover and characterize planets from the unique format of extreme precision binary relative astrometry data. We present MARA, the Microarcsecond Astrometric Retrieval Algorithm, specifically designed for these data. We describe the design and format of the MARA pipeline, and demonstrate its accuracy and performance with a series of validation tests on simulated data, using the SHERA SMEx mission concept as an example. Our injection/recovery tests show that with these data, MARA is able to detect and characterize rocky planets in the habitable zone of alpha Cen A, down to a coplanar mass of about 1 Earth mass in 1 year orbits. Expanding to a range of input planet masses and periods for the same example mission, we find that the results from these injection/recovery tests generally agree with the analytic predictions of binary relative astrometry sensitivity. We use MARA to map out the expected completeness as a function of planet mass and period, which in this case reaches down to about 0.5 M Earth masses at 3 year orbits around alpha Cen A. These depth-of-search calculations will be a vital ingredient in demographics calculations from the final data from a binary relative astrometry mission.
Read the full abstract

All authors William Roberson, Eric L. Nielsen, Jessie L. Christiansen, Gautam Vasisht, Eduardo Bendek, Alex Davis, Eric E. Mamajek, Catherine A. Clark, Kaitlin M. Kratter, Juliette Becker, Michael R. Meyer

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

Responses of the X-ray spectrometer/imager STIX onboard Solar Orbiter

Hualin Xiao, Olivier Limousin, Ewan Dickson et al. (+1 more)

Solar flares are explosive events that release X-rays from hot plasma and accelerated electrons. The STIX instrument on the Solar Orbiter provides imaging spectroscopy of solar X-ray emissions from 4 to 150 keV. To interpret the STIX data accurately, understanding the instrument's response is crucial. Given the complexity of interactions of X-rays with the instrument, we developed a detailed Monte Carlo model for STIX based on Geant4. The model accurately depicts the instrument's components, such as grids, detectors, X-ray windows, and collimators, with their responses. We studied various effects, including grid shadowing, fluorescent X-rays emitted by materials in STIX, and grid transmission, to assess their impacts on STIX's scientific goals. Model validation was performed using Crab Nebula observations, a standard calibration source that provides reliable ground truth for X-ray instruments. Our simulations align with the Crab Nebula observations within the uncertainties, thereby validating the accuracy of the Geant4 model and showcasing its potential for interpreting STIX data. With the help of the generated response matrices, which are indispensable for solar spectroscopy, we discuss the applications and limitations of the model for future STIX data analysis.
Read the full abstract

All authors Hualin Xiao, Olivier Limousin, Ewan Dickson, Säm Krucker

Instrumentation and Methods for Astrophysics

Microlensify: a Transformer Based Machine Learning Classifier for Microlensing Events Trained on TESS Light Curves

Atousa Kalantari, Somayeh Khakpash, Sedighe Sajadian et al. (+3 more)

Microlensing can reveal populations of faint compact objects that are otherwise difficult to detect. Depending on their design, all-sky surveys have the potential to search for these objects across the sky. The Transiting Exoplanet Survey Satellite (TESS), primarily designed to detect transiting exoplanets, also provides near all-sky coverage with high cadence. In this work, we use TESS data to search for microlensing candidates using both traditional and machine-learning methods and to identify associated false positives in high-cadence surveys. Microlensify is a physics-informed, transformer-based variational autoencoder trained on simulated single-lens microlensing light curves and real TESS Sector 12 data. The model classifies events, reconstructs light curves, and estimates microlensing event durations. Applied to $\sim 5.6$ million TESS light curves, it identified between $0.036\%$ and $1.89\%$ as microlensing candidates across different TESS pipelines. After applying microlensing detection metrics and cross-matching with SIMBAD, we obtained a final list of candidates and identified false positives including long-period variables, Mira variables, cataclysmic variables, red giants, and transients. We also found Gaussian-like peaks caused by asteroid crossings, a potential source of false positives in high-cadence microlensing surveys. The model also predicts event duration with an accuracy of $R^2 = 0.97$. The model was further tested on published events from different ground-based microlensing surveys, confirming 92.7% as microlensing, demonstrating its applicability across surveys with different cadences.
Read the full abstract

All authors Atousa Kalantari, Somayeh Khakpash, Sedighe Sajadian, Hosein Haghi, Willow Fox Fortino, Rosanne Di Stefano

Instrumentation and Methods for Astrophysics

ADORA: a differentiable optical modeling and astrometric retrieval framework for SHERA

Dylan McKeithen, Stuart Shaklan, Gautam Vasisht et al. (+4 more)

Searching for Habitable Exoplanets with Relative Astrometry (SHERA) is a proposed Small Explorer mission concept designed to measure the separation of nearby binary stars at microarcsecond-class precision. Recovering this signal requires separating astrophysical motion from coupled changes in pointing, plate scale, wavefront error, spectral response, and detector calibration. We present the Astrometric Differentiable Optics and Retrieval Algorithm (ADORA), an image-domain framework that combines a three-plane differentiable physical-optics model with a layered astrometric inference algorithm. The forward model includes a diffractive pupil, mirror-specific wavefront error and beamwalk, polychromatic source and throughput models, and configurable detector effects. Per-frame registration states are treated locally and eliminated through Schur reduction before the slower astrometric and instrument state is updated in a prior-whitened Fisher eigenbasis. Five-minute matched-model simulations show no detected separation bias at the current Monte Carlo depth and approximately 11 uas realization-to-realization scatter. A SHERA target sweep reveals a more-than-fivefold variation in astrometric information between Alpha Centauri and 61 Cygni, motivating future target-dependent accumulation and update cadence. High-order-wavefront knowledge error can drive the retrieval toward a strongly biased astrometric solution while leaving the local posterior sigma nearly unchanged, demonstrating that statistical curvature alone does not capture unmodeled bias. Pixel-position errors across the tested range remain near the matched-model recovery scale indicating robustness to certain detector calibration errors. ADORA provides a flexible framework for studying astrometric extraction, calibration-bias diagnosis, and future SHERA requirements.
Read the full abstract

All authors Dylan McKeithen, Stuart Shaklan, Gautam Vasisht, Joe Green, Rhonda Morgan, Louis Desdoigts, Peter Tuthill

Instrumentation and Methods for Astrophysics

Shaping SHAPE - A spectro-polarimeter onboard Chandrayaan-3 to observe Earth as an Exoplanet

Anuj Nandi, Swapnil Singh, Bhavesh Jaiswal et al. (+33 more)

Spectro-polarimetry of HAbitable Planet Earth (SHAPE) is an experimental instrument onboard the Propulsion Module (Orbiter) of the Chandrayaan-3 mission, designed to perform disc-integrated spectro-polarimetric observations of Earth from lunar and highly elliptical Earth orbits. SHAPE is a compact, lightweight spectro-polarimeter comprising three subsystems: the Electro-Optical Detector System (EODS)-Optics, EODS-Electronics, and Radio Frequency Source (RFS). An Acousto-Optic Tunable Filter (AOTF), driven by an in-house-developed 80$-$135 MHz RF source, provides spectral filtering in the near-infrared (NIR) wavelength range of 1.0$-$1.7 $\mu$m and produces two narrow-band beams with mutually perpendicular linear polarization states. The instrument optics, with a field of view of approximately 2.6{\deg}, focus the two beams onto InGaAs detectors. A spectral resolution of 2$-$4 nm is achieved using in-house-designed low-noise front-end electronics. The instrument also incorporates processing and power electronics for signal processing, detector biasing, and subsystem control. We present the overall instrument design, results from pre-launch ground-based testing, and in-orbit operational performance. The current configuration enables SHAPE to measure disc-integrated signatures of Earth over a range of phase angles, providing a test bed for characterizing Earth-like exoplanets and benchmarking future exoplanet observations.
Read the full abstract

All authors Anuj Nandi, Swapnil Singh, Bhavesh Jaiswal, Anand Jain, Smrati Verma, Reenu Palawat, Ravishankar B. T., Brajpal Singh, Priyanka Das, Supratik Bose, Supriya Verma, Waghmare Rahul Gautam, Yogesh Prasad K. R., Bijoy Raha, Bhavesh Mendhekar, Sathyanaryana Raju K., Srinivasa Rao Kondapi V., Sumit Kumar, Mukund Kumar Thakur, Vinti Bhatia, Nidhi Sharma, Govinda Rao Yenni, Neeraj Kumar Satya, Venkata Raghavendra, Vivechana M. S., Evangelin Leeja Justin, Praloy Karmakar, Naga Manjusha J., Motamarri Srikanth, Abhishek Singh, Prabakaran B., Honey Gupta, Priyanka Mishra, Chinmay Kumar Rajhans, Kalpana K., Veeramuthuvel P

Instrumentation and Methods for Astrophysics

Design, assembly, and initial test results of a cryostat for holographic characterization of microwave telescopes

Jon E. Gudmundsson, Miranda Eiben, Thomas J.L.J. Gascard et al. (+1 more)

We describe the design, fabrication, assembly, and room-temperature vacuum qualification of a 1.4-m long cylindrical cryostat developed for holographic testing of cryogenic microwave telescope optics. The system consists of a welded 6061-aluminum vacuum vessel containing nested 45- and 4-K aluminum radiation shields, cooled by a two-stage pulse-tube cryocooler through commercial OFHC copper flexible thermal straps. The intermediate 45-K stage intercepts radiative, conductive, and wiring heat loads from room temperature, while the 4-K stage defines the volume used for optical testing. The cryostat includes a 38-cm aperture for a microwave-transparent vacuum window and is sized to accommodate full-scale optical assemblies relevant to cosmic microwave background instrumentation. We summarize the cryostat architecture, lightweighted radiation shields, G-10 support flexures, welded vacuum-vessel fabrication, and room-temperature leak-checking campaign. Iterative helium leak checking and weld repair reduced the observed leak rate in the cryostat by over three orders of magnitude.
Read the full abstract

All authors Jon E. Gudmundsson, Miranda Eiben, Thomas J.L.J. Gascard, Eve M. Vavagiakis

Instrumentation and Methods for Astrophysics

Effects of manufacturing tolerances on the performance of metamaterial microwave anti-reflection coatings

Rustam Balafendiev, Miranda Eiben and Jon E. Gudmundsson

Metamaterial anti-reflection coatings (ARC) are used in a variety of applications, including: lenses, filters, and absorbers. Typically, the design of a given ARC is done within an infinite medium approximation, which presupposes that every unit cell on the interface is identical. However, in realistic applications, the geometry of a given ARC usually has some degree of variability, be it due to the shape of the surface inherent to the application, like in a lens, or manufacturing tolerances. This variation may alter the performance of the optical element in unanticipated ways, by creating additional scattering, enabling diffractive maxima that would normally be absent and, most crucially, changing the transparency of the ARC as a function of frequency. In this work we utilize full-wave modeling of finite samples of plastic which are matched with free space using a metamaterial ARC on both of their interfaces. By adding a degree of randomness to the ARC geometry we attempt to characterize the extent to which a given variation affects the expected performance of an ARC.
Read the full abstract

Instrumentation and Methods for Astrophysics · Cross-listed from physics.ins-det

Identifying Cost-Favorable Locations for Cosmic Explorer

Laurence Datrier, Geoffrey Lovelace, Tooba Ansar et al. (+19 more)

Cosmic Explorer (CE) is a proposed next-generation gravitational-wave observatory that aims to extend our gravitational-wave vision to the edge of the observable universe. With a foundation of technology proven by the National Science Foundation's Laser Interferometer Gravitational-Wave Observatory (LIGO), CE will observe black holes and neutron stars across cosmic time, explore the nature of extreme matter with high fidelity, and probe the nature of gravity and fundamental physics. CE's reference design consists of two widely separated L-shaped detectors to be located in the conterminous United States, one with 20 km arms and one with 40 km arms. As of 2026, CE is in its design and site evaluation phase, with plans to begin observing in the early 2040s together with the Einstein Telescope in Europe. The size of CE observatories—up to an order of magnitude larger than the 4 km LIGO observatories—presents a significant challenge for identifying suitable candidate sites where CE will achieve its science goals, be built within cost boundaries, attract and retain a workforce, and align with community values. In this paper, we report on the design and use of a Python package, the Cosmic Explorer Location Search (CELS) package, to identify cost-favorable sites for CE. For a specified detector location and L-shaped geometry in the conterminous United States, CELS estimates site-preparation costs associated with excavation, land clearing, and land acquisition, while accounting for the scientific effects of detector tilt, arm length, and arm opening angle. After describing the package's methods, we present results for a national-level cost and positioning analysis that complements a recent national suitability analysis. We also discuss how future improvements to CELS will allow deeper, more local studies as the Cosmic Explorer team narrows its list of potential locations.
Read the full abstract

All authors Laurence Datrier, Geoffrey Lovelace, Tooba Ansar, Lance Blagg, Warren Bristol, Matthew Evans, Chris Lukinbeal, Vuk Mandic, Kiet Pham, Jocelyn Read, Sarmad Rameez, Amber Romero, Oscar Romero, Babatunde Isaac Rotimi, Joshua B. Russell, Andrew Saenz, Francois Schiettekatte, Robert Schofield, David H. Shoemaker, Bretton Simpson, Bram J.J. Slagmolen, Joshua R. Smith

Instrumentation and Methods for Astrophysics

Real-Time RFI Mitigation in SPOTLIGHT: A Two-Stage Approach for Transient Searches

Raghav Wani, Jayanta Roy, Harshavardhan Reddy et al. (+10 more)

Radio Frequency Interference (RFI) remains one of the primary challenges limiting the sensitivity and reliability of modern radio transient surveys, particularly for real-time searches of fast radio transients. The SPOTLIGHT system is a commensal real-time transient search backend operating at the upgraded Giant Metrewave Radio Telescope (uGMRT), where robust and computationally efficient RFI mitigation is essential for sustained operations. We present the real-time two-stage RFI mitigation framework developed for SPOTLIGHT, comprising an antenna-level voltage-filtering module (VOLT) operating prior to correlation beamforming and the SPOTLIGHT Time-domain RFI Processing Engine (STRIPE), a statistical RFI-filtering framework applied to beamformed data. Together, these complementary techniques mitigate a broad spectrum of RFI, ranging from broadband impulsive interference mitigated by VOLT to narrowband spectrally confined spurious signals mitigated by STRIPE, while remaining computationally efficient enough to satisfy the stringent requirements of real-time processing. The framework is evaluated using routine commensal GMRT observations, controlled 76 pulsar observations, and benchmarking against PRESTO's rfifind. The deployed system reduced the false detection rate by 98%. The recovered astrophysical pulses exhibit a 2.7x improvement in S/N after the two-stage filtering compared with the unfiltered data. These improvements enhance SPOTLIGHT's detection efficiency, sensitivity, and operational reliability, strengthening its capability to discover radio transients with the uGMRT.
Read the full abstract

All authors Raghav Wani, Jayanta Roy, Harshavardhan Reddy, Sanjay Kudale, Ujjwal Panda, Karel Adamek, Wesley Armour, Kshitij Bane, Kaushal Buch, Jayaram Chengalur, Jyotirmoy Das, Sridhar Gajendran, SPOTLIGHT Collaboration

Instrumentation and Methods for Astrophysics

Physical Optics Analysis of Polarization Effects in SO LAT Reflectors

Xiaodong Ren, Patricio A. Gallardo and Jon E. Gudmundsson

We present a physical-optics analysis of the polarization response of the reflective optical of the Simons Observatory Large Aperture Telescope (SO LAT). Far-field co-polar and cross-polar beam patterns are simulated for representative feedhorn positions, and the corresponding polarization-angle offsets are evaluated. The results show that the crossed-Dragone reflector system has good polarization performance. Off-axis feed positions introduce small, position-dependent offsets in the far-field polarization orientation, with a maximum value of 0.23 degrees, due to optical asymmetry. The relative polarization-angle offset under feedhorn polarization rotation, however, remains consistent with zero. No significant frequency dependence is found over the frequencies considered. These results provide a practical reference for polarization-angle calibration and for assessing reflector-induced polarization systematics in the SO LAT.
Read the full abstract

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

Towards end-to-end Bayesian forward models in global 21-cm cosmology: surrogate modelling and marginalisation of beam uncertainty

Jacob L. Tutt, Dominic J. Anstey, John Cumner et al. (+3 more)

Robust statistical inference in global 21-cm cosmology requires end-to-end uncertainty quantification that jointly handles the highly degenerate cosmological signal, foreground emission, and instrumental response. Although electromagnetic simulations capture physical antenna properties in a parametrised way, multi-hour runtimes make their integration within likelihood-based sampling frameworks infeasible. Most existing approaches therefore assume a single precomputed beam, a fragile assumption given our demonstration that realistic mismatches can severely bias the recovered cosmological and foreground parameters. To address this, we present an accelerated and differentiable Bayesian framework that incorporates an informed surrogate representation of chromatic beam uncertainty directly into a forward-modelling pipeline. Treating the physical antenna properties as nuisance quantities, we apply a two-stage decomposition directly to simulated directivity patterns, reducing the instrumental parameterisation by two orders of magnitude while retaining the angular and spectral structure required for accurate beam reconstruction. Exploiting the linearity of the resulting surrogate, we use analytical marginalisation to allow the continuous instrumental uncertainty to be propagated into the final posteriors and Bayesian evidence without directly sampling the beam space. Testing the framework against a suite of unseen beams and cosmological signals, we recover the true inputs at approximately the instrumental-noise level. We further show that, for the uncertainty considered here, as few as 100 electromagnetic simulations are sufficient to construct an effective surrogate, substantially reducing the simulation burden for future analyses. This framework provides a scalable, statistically rigorous route towards hardware-accelerated uncertainty quantification in global 21-cm cosmology.
Read the full abstract

All authors Jacob L. Tutt, Dominic J. Anstey, John Cumner, Harry T. J. Bevins, Jean Cavillot, Eloy de Lera Acedo

Instrumentation and Methods for Astrophysics

Asgard/NOTT: Status of laboratory nulling performance

T. Mattheussen, R. Laugier, D. Defrère et al. (+26 more)

Nulling interferometry enables the direct detection of faint companions and circumstellar structures at angular separations unresolvable by classical, diffraction-limited imagers, whilst dramatically improving the measurable contrast. The Asgard/NOTT nulling instrument aims to achieve a contrast performance of 10^-5 in the L' wavelength band (3.5 - 4.0 {\mu}m), enabling observation and characterization of young giant exoplanets near the snowline and hot exozodiacal dust. Previous studies have verified the nulling capabilities, of the chip in ambient conditions and of the test bench in cryogenic conditions. This work aims to add the first ambient performance assessment of the test bench with spectrally dispersed light. Necessary revisions are made to the data acquisition and calibration pipeline and fringe scans are carried out, modeled and fitted. The splitting ratios of the 4-telescope nulling beam combiner, a photonic Gallium Lanthanum Sulfide (GLS) chip, are moreover characterized on the bench, showing tentative agreement with previous chip characterization. The null performance has worsened, the achieved contrast of ~ 10^-1 being one order of magnitude higher than what earlier characterized performance showed. Multiple future changes to the test bed and to the approach taken promise an improved characterization of performance. In particular, the input beam intensities will be deliberately mismatched to account for the imbalanced splitting ratios of the directional couplers. With the installation of the final cryostat and camera, the developed tools will be leveraged to re-assess the performance in ambient and cryogenic conditions.
Read the full abstract

All authors T. Mattheussen, R. Laugier, D. Defrère, G. Garreau, P. Chingaipe, G. Raskin, M. Salman, K. Missiaen, B. Vandenbussche, W. Verstraeten, J. Morren, A. Kuriakose, M. Ireland, M.-A. Martinod, A. Sanny, S. Gross, L. Labadie, A. Bigioli, A. Jóo, S. Madden, A. Mazzoli, G. Medgyesi, S. Ertel, T. A. Stuber, J. P. Scott, S. Kraus, F. Martinache, X. Haubois, N. Schuhler

Instrumentation and Methods for Astrophysics

Demonstration of a multimode-to-multimode photonic lantern for astronomy

Marina Centenera-Merino, Andrew Ross-Adams, Christopher Betters et al. (+14 more)

Photonic lanterns have been widely used in astronomy as low-loss multiplexing devices, typically coupling light from a multimode input into several single-mode outputs. In this work, we present the first multimode-to-multimode photonic lantern specifically designed to combine light from several multimode fibers into a single multimode waveguide. We fabricated and characterized the devices at multiple wavelengths to evaluate the performance of the adiabatic multimode transition. The measured efficiencies exceed $90\ \%$, demonstrating low-loss multimode propagation and efficient modal transfer through the lantern structure. This architecture enables efficient multimode beam combination and represents a significant step toward scalable modular telescope concepts without requiring diffraction-limited injection.
Read the full abstract

All authors Marina Centenera-Merino, Andrew Ross-Adams, Christopher Betters, Pedro J. Amado, Jesus Aceituno, Kalaga Madhav, Stefan Cikota, F. Javier Flores, Julius Göhring, Abani S. Nayak, Jose Luis Ortiz, David Peréz-Medialdea, Francisco J. Pozuelos, Martin M. Roth, Mabel Ruíz-López, Miguel Andrés Sánchez-Carrasco, Sergio Leon-Saval

Instrumentation and Methods for Astrophysics

VERITAS 2.3.1: Optimisation and Characterisation of the Enhanced Readout ASIC for the NewAthena Wide Field Imager

Ajay Kumar Dakshinamurthy, Sven Herrmann, Peter Orel et al. (+7 more)

VERITAS 2.3.1 is the next iteration of the VErsatile Readout based on Integrated Trapezoidal Analogue Shapers (VERITAS) integrated circuit (IC) architecture for high-speed, low-noise readout of DEPleted Field Effect Transistor (DEPFET) detectors in the Wide Field Imager (WFI) on ESA's NewAthena X-ray satellite. Building on VERITAS 2.3, which demonstrated a short processing time of 2.5 us per readout and a system noise target of about 3 e- ENC RMS, the VERITAS 2.3.1 revision has been improved with additional features and targeted optimisations of existing analogue and digital blocks, alongside refined layout routing to reduce parasitic effects, to improve transient behavior, cross talk, manufacturability, and reliability while preserving the proven VERITAS architecture. The functionality and performance of VERITAS 2.3.1 was characterised in two steps. First by using a dedicated application specific integrated circuit (ASIC) only test setup. Second, a full scale module test setup is used, with integrated DEPFET sensors and readout electronics, under vacuum and at mission like temperatures. This paper presents the design updates and implementation details of the VERITAS 2.3.1, compares its measured performance to that of VERITAS 2.3, and discusses the impact of the added features, block-level optimisations, and routing improvements on overall system performance.
Read the full abstract

All authors Ajay Kumar Dakshinamurthy, Sven Herrmann, Peter Orel, Anna-Katharina Schweingruber, Astrid Mayr, Johannes Muller-Seidlitz, Jonas Reiffers, Sebastian Albrecht, Steven W. Allen, Glenn Morris

Instrumentation and Methods for Astrophysics

Estimation of systematic error from bulk deformation of end test mass induced by photon calibrator for LIGO post-O5 gravitational wave projects

Daiki Tanabe, Aloysius Niko, Kun-Yao Chang et al. (+4 more)

We studied the bulk deformation of the end test masses (ETMs) of gravitational wave (GW) detectors caused by calibration devices named Photon Calibrator (Pcal). This bulk deformation is one of the source of calibration error since it induces non-linear displacement from the ideal pendulum motion of the ETM. Particularly, it is the dominant error source above 1500 Hz which is crucial to the studies of neutron star mergers. The displacement also depends on beam offsets of the main interferometer (IFO) beam and Pcal beams. We conceptually described frequency dependent effect of bulk deformation and evaluated it in several cases of the beam offset with finite-element analysis (FEA) software, for ETM models of Advanced LIGO (aLIGO), KAGRA, Advanced Virgo (AdVirgo), and LIGO A#.
Read the full abstract

All authors Daiki Tanabe, Aloysius Niko, Kun-Yao Chang, Yuki Inoue, Dripta Bhattacharjee, Richard Savage, Henry Tsz-King Wong

Instrumentation and Methods for Astrophysics

Millimeter and sub-millimeter characterization of polymers used for infrared filters in high-sensitivity cryogenic microwave telescopes

Miranda Eiben, Rustam Balafendiev, Thomas Gascard et al. (+1 more)

Vacuum windows and infrared filters are important transmissive optical components in millimeter receivers, as they hold out the atmosphere and reduce radiative loading on cold stages, thereby improving cryogenic performance. However, the complex optical properties of the materials commonly used for windows and filters are poorly characterized, particularly in-band and in the sub-millimeter regime. The absorption and scattering properties of these materials are becoming increasingly important for designing high-sensitivity millimeter instruments, as their loosely constrained properties are one of the greatest sources of uncertainty remaining in noise modeling. We report the absorption in the millimeter and sub-millimeter regime of nylon 6, nylon 6/6, PTFE and polyethylene (both bulk HDPE and foam HDPE used in radio transparent filter stacks). Additionally, we report the relative power scattered out of the main beam by these materials from 90 to 330 GHz, measured in free space by a robot-enabled scanning vector network analyzer.
Read the full abstract

All authors Miranda Eiben, Rustam Balafendiev, Thomas Gascard, Jon E. Gudmundsson

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

Technical Proposal for the Atom Interferometer CERN Experiment (AICE) Facility

Gianluigi Arduini, Nadja Augst, Mark G. Bason et al. (+79 more)

We present the technical proposal for the Atom Interferometer CERN Experiment (AICE), a $\mathcal{O}(100)$ m vertical atom interferometer to be installed against the wall of the PX46 access shaft to the LHC. AICE is conceived as a versatile and flexible long-baseline atom-interferometry facility whose primary scientific goal is probing for bosonic ultralight dark matter (ULDM) in a mass range inaccessible to other experiments, with a secondary goal of pioneering the exploration of gravitational waves (GWs) with frequencies in the range ${\sim}$0.03-3 Hz as a pathfinder for future longer-baseline detectors. The initial configuration employs ultracold $^{87}$Sr atoms in a single-photon 698-nm interferometer with three shaft-based atom sources in a multi-source gradiometer geometry, supported by one surface reference source for laser stabilisation and diagnostics, to target scalar ULDM. Operation with $^{88}$Sr will give sensitivity to axion-like particles (ALPs), vector ULDM with $B-L$ couplings and violation of the principle of equivalence, while a $^{171}$Yb upgrade will improve the sensitivity to $B-L$ couplings and equivalence violations. Probing the Einstein equivalence principle (EP) and measuring $\alpha$ will proceed in parallel with the ULDM searches. A conceptual feasibility study and a detailed technical implementation study have established that PX46 is a uniquely mature and implementation-ready site, with no technical showstoppers. Completing site preparation works during LS3 would enable the subsequent installation and operation of AICE without impacting HL-LHC operations. The detector design builds on the VLBAI and MAGIS experiments and the AION-10 Technical Design Report, scaling the strontium gradiometer architecture to the $\sim$100 m baseline. AICE is endorsed by the TVLBAI Proto-Collaboration, comprising 57 institutions in 22 countries.
Read the full abstract

All authors Gianluigi Arduini, Nadja Augst, Mark G. Bason, Charles Baynham, Andrea Bertoldi, Gianfranco Bertone, Diego Blas, Daniela Bortoletto, Sougato Bose, Roberto Ales Bozzi, Oliver Buchmueller, Tamara Alice Bud, Clare Burrage, Sergio Calatroni, John Carlton, Vassilis Charmandaris, Maria Luisa Chiofalo, Pierre Cladé, Jonathon Coleman, Fabio Corsanego, Albert De Roeck, Arnaud Devienne, Fabio Di Pumpo, John Ellis, Pierre Fayet, Chris Foot, Elina Fuchs, Naceur Gaaloul, Susan Gardner, Enno Giese, Eduardo Granados, Saïda Guellati-Khelifa, Michael Guinchard, Timo Hakulinen, Tiffany Harte, Richard Hobson, Michael Holynski, Angelo Infantino, Alex Kehagias, Eva Kilian-Rademacher, Wolfgang Korsch, Damien Lafarge, Samuel Lellouch, Lucas Lombriser, Elias Lopez Asamar, J. Luis Lopez-Gonzalez, Michele Maggiore, Charline Marcel, Anna Marchant, Christopher McCabe, Gaetano Mileti, Peter Millington, Jeremiah Mitchell, Noam Mouelle, Angel Navascues Cornago, François Pillon, Rosa Poggiani, Johann Rafelski, Ernst M. Rasel, Maike Reckermann, Albert Roura, Rui Samoes, Federico Sanchez Nieto, Jack Sander, Carlo Scarcia, Jesse Schelfhout, Wolfgang Schleich, Dennis Schlippert, Ulrich Schneider, Steven Schramm, Florian Schreck, Olga Sergijenko, Marcelle Soares-Santos, Guglielmo M. Tino, Jonathan N. Tinsley, Tristan Valenzuela, Daniel Valuch, Maurits van der Grinten, Klaasjan van Druten, Ville Vaskonen, Wolf von Klitzing, Michael Werner

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

An Empirical Effective-Temperature Calibrations for Galactic B/A Supergiants

N.L.Vaidman, A.S.Miroshnichenko, Sh.T.Nurmakhametova et al. (+9 more)

We present empirical effective temperature Teff calibrations for Galactic supergiants of spectral types B5-A5 based on optical spectra. The relationships were derived from a reference sample with adopted literature temperatures and use equivalent widths, central line depths, and ratios of selected spectral features as temperature indicators. Quadratic relationships are established for individual diagnostics and their ratios. Collectively, the calibrations span a Teff interval from 8 400 K to 14 700K, while the validity range of each relationships is individually specified. Detailed quantitative atmospheric analyzes remain indispensable for deriving physically consistent stellar parameters. However, their application to extensive spectroscopic samples is observationally and computationally demanding. The empirical relationships presented here provide a homogeneous and readily applicable temperature scale for the characterization of Galactic BA supergiants. The complete calibration tables, including fitted coefficients and uncertainty information, together with an interactive Python tool to apply the relationships, are publicly available through Zenodo. The reduced continuum-normalized spectra and associated metadata are published through a VO–compliant service of the Kazakhstan National Virtual Observatory.
Read the full abstract

All authors N.L.Vaidman, A.S.Miroshnichenko, Sh.T.Nurmakhametova, S.Danford, S.A.Khokhlov, I.M.Izmailova, Ch.T.Omarov, S.V.Zharikov, D.E.Yakhiya, A.T. Agishev, A.A.Khokhlov, D.T.Agishev

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

Beyond Idealized PAHs: Infrared Signatures of Carbon-Chain Defects from Shock Synthesis

Xiaoting Tan, Zhao Wang, Zu-Jia Lu et al. (+2 more)

Polycyclic aromatic hydrocarbons (PAHs) are widely recognized as carriers of the aromatic infrared bands (AIBs). However, most spectral models rely on idealized structures that fail to capture the energetic environments of interstellar PAH formation. This work investigates the infrared (IR) signatures of PAHs formed under shock conditions and explores whether produced defective structures can explain observational features unpredicted by standard, idealized models. We combine two-stage reactive molecular dynamics simulations of PAH formation via condensation and shock processing with density functional theory spectral calculations, and compare our theoretical results with James Webb Space Telescope (JWST) observations of NGC 7023 and MRK 1066. Shock processing produces PAHs featuring fullerene-like carbon skeletons and linear carbon-chain attachments. These structural defects yield distinct IR signatures, including prominent carbon-chain stretching features at 4.6-5.5 micron that is absent in ideal PAHs, and significantly enhanced out-of-plane skeletal modes in the 14.5-20 micron regime. Our findings attribute the observed 5.2 micron band in NGC 7023 and MRK 1066 to carbon-chain vibrations and the 15-18 micron emission to curved skeletal modes, providing observational support for the prevalence of defective, shock-formed PAHs in the interstellar medium.
Read the full abstract

All authors Xiaoting Tan, Zhao Wang, Zu-Jia Lu, Houda Haidar, Dimitra Rigopoulou

Tuesday 18 August

Instrumentation and Methods for Astrophysics

The Cross-Survey Decade: A Call to Action

Gioia Rau, Robert Benjamin, Federica Bianco et al. (+24 more)

By 2027, three flagship wide-field surveys will be operating simultaneously from ground and space, observing overlapping sky and representing more than $6 billion in US and European public investment. Together they will produce overlapping petabyte-scale datasets across thousands of square degrees. This is a different class of challenge: the observations are no longer the bottleneck; realizing their joint scientific return now depends on shared computational infrastructure and coordination. Decades of community studies show that combining these datasets does more than improve precision. For science ranging from weak lensing to transient discovery and Galactic-plane astronomy, joint processing and analysis can unlock capabilities no single survey provides alone. Yet the required infrastructure – joint pixel-level processing, cross-calibration and validation, interoperable data access, and the people to build and sustain it – falls outside any single mission or institution's mandate. We issue a call to action for cross-survey science infrastructure, built around four pillars: (1) joint pixel-level processing and validation; (2) an AI-ready data substrate for scientific foundation models; (3) standardized, interoperable data access across surveys, democratizing participation in astrophysical discovery; and (4) dedicated personnel and career pathways. We outline concrete steps for policymakers, agencies, observatories, universities, the research community, and philanthropy, and argue that the moment to act is now, while foundational technical choices can still be aligned at a fraction of the cost of reconciling them later.
Read the full abstract

All authors Gioia Rau, Robert Benjamin, Federica Bianco, Ranga-Ram Chary, Andy Connolly, Cecilia Garraffo, Suvi Gezari, Leanne P. Guy, Željko Ivezić, Stephanie Juneau, Vicky Kalogera, Mansi M. Kasliwal, François Lanusse, Zack Li, Rachel Mandelbaum, Peter Melchior, Stella Offner, Antonella Palmese, Jason Rhodes, Edward Schlafly, Kartik Sheth, Rachel Street, Michael Troxel, Tony Tyson, Beth Willman, Michael Wood-Vasey, Yuanyuan Zhang

Instrumentation and Methods for Astrophysics

The Atacama Cosmology Telescope: Passband Measurements with an Analysis of Systematic Errors

Thomas Alford, Rahul Datta, Erminia Calabrese et al. (+14 more)

We present measurements of the spectral response of the four Advanced ACTPol (AdvACT) multichroic detector arrays, which observed in frequency bands centered near 30, 40, 90, 150, and 220 GHz. The passbands were measured with a Fourier transform spectrometer (FTS) combined with coupling optics that direct and match the output of the FTS to the AdvACT receiver. We perform optical simulations of the FTS and coupling optics in order to model frequency-dependent systematic effects in this system. We use these simulations to apply corrections to the measurements and evaluate the remaining systematic uncertainty. We combine these systematic estimates with statistical errors to determine the measured passbands and their uncertainties from our FTS measurement, which are typically 0.75 to 1.5% per detector array. We present the passband characteristics for all measurements made by ACT in a common framework. Additionally, we discuss the performance achieved as well as ways to improve passband measurements in the future.
Read the full abstract

All authors Thomas Alford, Rahul Datta, Erminia Calabrese, Steve K. Choi, Shannon M. Duff, Adriaan J. Duivenvoorden, Joseph Golec, Matthew Hasselfeld, J. Colin Hill, Johannes Hubmayr, Jeffrey McMahon, Michael D. Niemack, Lyman A. Page, Alex Thomas, Cristian Vargas, Yuhan Wang, Edward J. Wollack

Instrumentation and Methods for Astrophysics

The VLA and High-Frequency SETI: Expanding the Search for Life

Talon Myburgh, Noah Stiegler, Chenoa D. Tremblay et al. (+2 more)

The Commensal Open-Source Multimode Interferometer Cluster (COSMIC) runs software that searches for technologies elsewhere in the Universe ("technosignatures") using the Karl G. Jansky Very Large Array (VLA). Specifically, it searches for narrowband signals that drift in frequency over time as a result of Doppler motions. Although this is the first study of high-frequency technosignatures that has been published from the COSMIC system on the VLA, it follows closely on previous work completed by an undergraduate research intern. Within the field of view of the VLA, the software on COSMIC creates coherent beams directed toward stars that may contain exoplanets from the Gaia catalogue. The recorded results follow a real-time software pipeline and are examined for technosignatures. Using a Taylor-Tree De-Dispersion algorithm to find narrow-band drifting signals, each recorded beam (coherent and incoherent) is searched for signals with a drift-rate with magnitudes up to $\pm$50Hz/s. All detections are stored as "hits" with the relevant snippet of data stored for posterity. The purpose of this work is to extend the high-frequency search by reviewing data from February 2024 to the present. Our study examines the impact of previously implemented and novel filters to find a selection of candidate signals. At the final stage of the pipeline, our objective is to study these resultant candidate signals spatially through imaging. The observations therefore probe regions of frequency and signal parameter space that have received comparatively limited coverage in previous SETI surveys.
Read the full abstract

All authors Talon Myburgh, Noah Stiegler, Chenoa D. Tremblay, Joe S. Bright, Ross A. Donnachie

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

Mapping the Information Geometry of an Unresolved Dark Matter Population using a Differentiable Strong Lensing Simulator

Alexandre Adam

Strong gravitational lensing is a unique probe of the matter power spectrum on small scales, where the abundance of dark matter subhalos in galaxies could be used to distinguish the predictions of the concordance cold dark matter model from alternatives such as warm dark matter. Extracting this signal poses major computational challenges, since perturbations of the lensing potential induced by substructure can be degenerate with both the macro-model of the lens and highly flexible models of the background source. Here, we introduce a framework to quantify these degeneracies using a differentiable strong-lensing simulator. Substructure is represented in a spectral basis confined to an annular domain surrounding the lensed image, allowing signals from a population of NFW subhalos to be encoded in a finite vector space. We then use the Fisher matrix to determine how much information about substructure is absorbed by nuisance components of the model. We find that macro-model degeneracies are largely confined to low-order perturbations of the lensing potential, while degeneracies with the source model can strongly suppress sensitivity across a broad range of scales as the expressivity of the source model is increased. Finally, we introduce the Fisher Graph Laplacian prior as a diagnostic tool to study how the internal degeneracies of the source model can be used to regulate the sensitivity of the data to an unresolved population of dark matter subhalos.
Read the full abstract

Instrumentation and Methods for Astrophysics

Radiation damage to the Hubble Space Telescope has been several years out of phase with the Solar cycle

Gavin Leroy, Juan Paolo Lorenzo Gerardo Barrios, Maximilian von Wietersheim-Kramsta et al. (+8 more)

As well as obtaining beautiful images of the Universe, the Hubble Space Telescope's CCD detectors are sensitive radiation dosimeters that have been monitored in Low Earth Orbit for more than 24 years. The rate of radiation damage they received has varied over each Solar cycle, but several years out of phase with the appearance of sunspots or coronal mass ejections. We investigate functional forms that successfully fit the time series of damage to telescopes elsewhere in the Solar system. We obtain remarkably accurate fits to Hubble data but with physically absurd parameter values. During image post-processing, such fits can be used empirically, to correct more than 99.5% of the radiation damage's effect on image quality. However, fits to the time series with physically reasonable parameters produce worse performance. Our results highlight the diversity of radiation environments in different parts of our Solar system, and the complexity of Low Earth Orbit in particular. Our results also motivate continued monitoring of radiation damage to currently operational spacecraft, to more reliably predict the rate of degradation in (and useful lifespan of) future missions.
Read the full abstract

All authors Gavin Leroy, Juan Paolo Lorenzo Gerardo Barrios, Maximilian von Wietersheim-Kramsta, Richard Massey, Richard G. Hayes, Jacob A. Kegerreis, David Lagattuta, Zane D. Lentz, James W. Nightingale, Jesper Skottfelt, Felix Vecchi

2608.18214 · 18 Aug · Paper presented at SPIE Astronomical Telescopes + Instrumentation 2026. Accompanying poster can be found at https://spie.org/astronomical-telescopes-instrumentation/presentation/Radiation-damage-to-the-Hubble-Space-Telescope-has-been-several/14145-131

Abstract PDF $TSCP ×3