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Physics Astrophysics Instrumentation and Methods for Astrophysics

astro-ph.IM Watch Instrumentation and Methods for Astrophysics

Thursday 13 August

Instrumentation and Methods for Astrophysics

Numerical Model Simulation of the Carruthers GCI Images

Heather Filippini, Alex Zhang, Evan Widloski et al. (+7 more)

The Carruthers Geocorona Observatory, launched in September 2025, is NASA's first mission devoted to investigating the fundamental nature of Earth's exosphere from its distant vantage in halo orbit around the Earth-Sun Lagrange (L1) point. Its primary payload, the GeoCoronal Imager, consists of two coaligned photometric imagers that measure the radiance of ultraviolet emission at 121.6 nm (Lyman-$\alpha$, or Ly-$\alpha$) from exospheric hydrogen atoms simultaneously at wide and narrow fields of view. In order to validate the calibration and hydrogen density retrieval algorithms used in the Carruthers data processing pipeline, we developed a comprehensive numerical simulator to produce realistic images similar to those collected by the actual imagers on orbit. This paper details the algorithms used to simulate the exospheric emissions, background scene components, and instrument measurement model necessary to produce synthetic raw images.
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All authors Heather Filippini, Alex Zhang, Evan Widloski, Jason McPhate, Lara Waldrop, Thomas Immel, John Clarke, Pratik Joshi, Michal Ondrejcek, Martin M. Sirk

Instrumentation and Methods for Astrophysics

JWST MIRI Medium Resolution Spectrometer Point Fixed Pattern Corrections: Cleaner and Higher Signal-to-Noise Spectra of Point Sources

Karl D. Gordon and David R. Law

The JWST Mid-Infrared Instrument Medium Resolution Spectrometer provides the capability to obtain spectra from 5-28 micron. The JWST data reduction pipeline removes the majority but not all of the instrument artifacts and the signal-to-noise (S/N) of the resulting spectra are limited by fixed pattern noise. Building on previous work, Point Fixed Pattern Corrections (PFPCs) are constructed using observations of O, A, and G dwarf flux calibration stars and asteroids taken using the default four point dither pattern. The PFPCs can be applied to spectra of point sources taken with target acquisition and the same dither pattern. They can be used alone or with the pipeline residual fringe correction depending on the sources spectral properties. Both narrow and broad artifacts are removed by the PFPCs improving the spectra regardless of their S/N. For higher S/N observations, the PFPCs significantly improve the S/N by up to factors of a few and S/N values of 1000 or more. The MRS-PFPC python package is provided to allow anyone to utilize the PFPCs for their own data.
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Instrumentation and Methods for Astrophysics

Optical concept model of the future cosmology project BISOU

Morgane Loquet Le Gall, Bruno Maffei, Pierre Guiot et al. (+2 more)

We present an optical analysis of BISOU (Balloon Interferometer for Spectral Observations of the primordial Universe), an astronomical balloon-borne pathfinder spectrometer developed as part of a preparatory study for a future space mission aiming at measuring spectral distortions of the cosmic microwave background (CMB). The BISOU optical system is based on a differential polarizing Fourier Transform Spectrometer (FTS) that receives inputs from both a sky-facing telescope and an internal calibration source. The FTS focal planes are equipped with bolometric detectors coupled to multimode feed horns, with distinct focal planes dedicated to the low (90 - 300GHz) and high (0.3 - 1.5THz) frequency bands. The optical analysis first relies on ray-tracing simulations to establish the overall configuration of the system, before proceeding to more advanced Gaussian beam and physical optics analyses.
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All authors Morgane Loquet Le Gall, Bruno Maffei, Pierre Guiot, Creidhe O'Sullivan, Neil Trappe

Instrumentation and Methods for Astrophysics

Optical development of the BISOU breadboard

Morgane Loquet Le Gall, Creidhe O'Sullivan, Bruno Borgo et al. (+4 more)

BISOU (Balloon Interferometer for Spectral Observations of the primordial Universe) is an astronomical balloon-borne pathfinder developed as part of a preparatory study for a future space mission aimed at measuring spectral distortions of the cosmic microwave background (CMB). A laboratory breadboard of the instrument is being developed at the Institut d'Astrophysique Spatiale (IAS), enabling the characterization of subsystems and instrument systematic effects, particularly in the optical system. The optical system is based on a differential polarizing Fourier Transform Spectrometer (FTS) that receives inputs from both a sky-facing telescope and an internal calibration source. The FTS focal planes include sub-K detectors coupled to multimode feed horns. The full spectral band, spanning between 90 and 1500 GHz, is sub-divided into two frequency sub-bands, thanks to the use of a dichroic. The optical analysis first relies on ray-tracing simulations to establish the overall configuration of the system, before proceeding to more advanced Gaussian beam and physical optics analyses.
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All authors Morgane Loquet Le Gall, Creidhe O'Sullivan, Bruno Borgo, Clémence De Jabrun, Valentin Sauvage, Neil Trappe, Bruno Maffei

Instrumentation and Methods for Astrophysics

FOSSIL's preliminary thermal architecture

Valentin Sauvage, Clémence de Jabrun, Anaïs Besnard et al. (+6 more)

FOSSIL (FTS fOr CMB Spectral diStortIon expLoration) is a proposed ESA M8 mission tailored to measure the spectral distortions monopole of the Cosmic Microwave Background (CMB) with a sensitivity three orders of magnitude beyond the COBE/FIRAS legacy measurement. Achieving this sensitivity demands an extraordinarily challenging cryogenic architecture: the scientific instrument must be maintained at 4.5 K, while the detector focal plane assembly operates at 50 mK. This paper presents an overview of the preliminary thermal architecture of the FOSSIL payload, from the spacecraft service module at 293~K down to the sub-kelvin detector stage. The design draws on heritage from the Planck and ARIEL missions and relies on a staged passive cooling chain comprising a multi-layer insulation blanket, three V-groove radiators (operating at approximately 130 K, 90 K, and 50 K), and a 25 K actively cooled shield fed by an ESA-provided 4 K mechanical cryocooler. Sub-kelvin temperatures are achieved via a multi-stage adiabatic demagnetisation refrigerator (ADR) developed for NewAthena/X-IFU, providing continuous cooling at 1.8 K and 350 mK, and 50 mK with an 80% duty cycle. The Focal Plane Assembly (FPA), housing four Kinetic Inductance Detector (KID) arrays at 50 mK, is thermally isolated from the 4.5 K bench via a carbon-fibre reinforced polymer (CFRP) hexapod with staged heat interception. We outline the staged cooling concept and show that the architecture closes with positive thermal margins at every stage; the detailed steady-state thermal budget will be presented in a forthcoming dedicated paper.
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All authors Valentin Sauvage, Clémence de Jabrun, Anaïs Besnard, Bruno Borgo, Ivan Charles, Jean-Marc Duval, Bruno Maffei, Sylvain Martin, Nabila Aghanim

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

A Radon Transform Perspective on Exoplanet Transits

Shotaro Tada

Transit light curves are usually analyzed under the assumption that the transiting planet has a circular sky-projected silhouette. However, planetary rotation, tides, rings, or atmospheric inhomogeneities can produce non-circular silhouettes. This raises the question of what information transit light curves can provide about the underlying two-dimensional attenuation map. In this paper, we show that, in a simple and transparent limit, the time derivative of the transit light curve during ingress or egress can be interpreted as a Radon-transform measurement of the planetary attenuation map, with the projection direction set by the local normal to the stellar limb. This viewpoint makes the information content of a single transit clear. Ingress and egress provide at most two projection angles, so the data constrain the Fourier transform of the attenuation map only along at most two radial slices, leaving a large null space. Physical constraints on the attenuation values and shape priors can reduce the range of viable solutions, but non-uniqueness generally remains. We further examine how realistic effects modify this picture. In particular, small stellar-limb curvature introduces weak sensitivity to transverse Fourier-space structure around the ideal slices, a sensitivity that is absent in the strict Radon-transform limit. These results provide a framework for understanding what transit light curves can and cannot reveal about non-circular planetary silhouettes.
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Instrumentation and Methods for Astrophysics

SNIFFLES I: Intended Emission, Unwanted Emission, and Unintended Radiation from Low-Earth Orbiting Satellites Impacting Radio Astronomy from 1-26 GHz

Balthasar Indermuehle and Liroy Lourenco

We present the first results of SNIFFLES, an ongoing observational programme to characterise intended emission, unwanted emission, and unintended radiation from NGSO systems across common radio astronomy receiver bands from 1-26 GHz (L, S, C, X, and K bands). Using the Australian 22 metre Mopra radio telescope near Coonabarabran, New South Wales, with followup observations from a single dish of the ATCA interferometer and its new BIGCAT backend, we conducted 4629 tracked observations of satellites from four NGSO constellations (Starlink, OneWeb, Amazon Leo, and Guowang), amounting to 375.9 hours of telescope time. Satellite identification was confirmed by correlating detected Doppler shifts with predicted ephemerides. We detected 2345 instances of intended emission, unwanted emission, and unintended radiation at 300+ unique frequencies from three of the four systems. The detections span all three interference classes affecting radio astronomy: (1) intended emission (including DTD), (2) unwanted emission (OOBE, including up to the fourth harmonic of the Starlink DTD signal at approximately 2.6 GHz, with the fourth harmonic detected near 10.5 GHz), and (3) unintended radiation from satellite platform electronics. Several detections fall within primary radio astronomy allocations, including 1613.19 MHz within the protected OH line band, and at 2690.76 MHz and 2700 MHz. At 2700 MHz, unintended radiation was detected in 76.9 percent of all observations of the relevant satellite version. ATCA followup measurements confirm flux densities up to eleven orders of magnitude brighter than typical astronomical sources, well in excess of levels that saturate radio astronomy receivers.
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Instrumentation and Methods for Astrophysics

Tropospheric Ducting Prediction based on GFS Model Data at Inyarrimanha Ilgari Bundara, the CSIRO Murchison Radio-astronomy Observatory

Balthasar Indermuehle and Hajime Suzuki

Tropospheric ducting transports terrestrial RFI over hundreds of kilometres into the ARQZWA at Inyarrimanha Ilgari Bundara, the CSIRO Murchison Radio-astronomy Observatory. We present a ducting prediction method based on vertical refractivity profiles derived from GFS data, validated against seven years of continuous spectrum monitoring between 88 MHz and 2.68 GHz. Per-transmitter basic transmission loss to the site is computed with Rec ITU-R P.452-16 above 100 MHz and Rec ITU-R P.1812-6 below it, over Copernicus GLO-90 terrain, driven at each timestep by the GFS-derived refractivity lapse along the path. Skill is scored as a stratified AUC, computed within month and three-hour strata. The median stratified AUC is 0.724 and 24 of 25 confidence intervals exclude chance. A time-percentage calibration derived from four pilot months transfers without retuning to the full record, and skill is flat through three days of forecast lead. A pooled GBM on the same physical features, augmented by a duct-corridor connectivity metric, reaches a mean test AUC of 0.806 over all 25 channels and 0.799 over the 16 on which the analytical predictor is itself skilled. In-situ LTE cell decoding confirms attribution: 86-97% of over-the-horizon cell detections fall within flagged event hours, the range spanning the four monitored LTE channels, and the decoded network identities match the licensing records. Ship AIS receptions at 162 MHz, each a self-located 12 W transmitter at a known sea position, provide VHF ground truth. The FM channels retain only weak skill, far below the ducting channels, and we attribute their events to near-threshold local sources after excluding ducting, sporadic-E and aircraft scatter. The method enables adaptive scheduling of observations away from frequencies affected by forecast ducting, and drives a live forecast service at the observatory. (Abstract abridged for arxiv)
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Instrumentation and Methods for Astrophysics · Cross-listed from astro-ph.EP

Are Hot Jupiters Tidally Disrupted During Stellar Main Sequence?

Qingru Hu, Wei Zhu, Yang Huang et al. (+1 more)

Once hot Jupiters (HJs) reach their very close orbits, they are expected to experience orbital decay due to tidal interactions with their host star. However, the strength of tidal dissipation is highly uncertain, and it remains an open question whether HJs are tidally disrupted during the stellar main sequence. A previous study found that HJ hosts have a smaller Galactic total velocity dispersion than their field star counterparts, which they interpreted as evidence of tidal disruption. We revisit this study and find that, after using the more reliable vertical velocity dispersion ($\sigma_W$) as the age indicator and accounting for the heterogeneity and anisotropy of their HJ sample, the kinematic age difference between their HJ hosts and matched field stars is significantly reduced. As an independent check, we collect HJs newly discovered by TESS and find that their $\sigma_W$ is statistically similar to that of matched field stars. We also find no statistically significant $\sigma_W$ difference between the field stars and the theoretically vulnerable ultra-hot Jupiters with $P<2$ d. Our results suggest that, after accounting for systematics in the age–velocity dispersion relation, there is no statistically strong evidence from the stellar kinematics that a large fraction of hot Jupiters around Sun-like stars are tidally destroyed during the stellar main sequence.
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All authors Qingru Hu, Wei Zhu, Yang Huang, Bowen Zhang

Wednesday 12 August

Instrumentation and Methods for Astrophysics

Laser-micromachined silicon-platelet feedhorns for large-scale submillimeter and millimeter-wave focal planes

Jason E. Austermann, James Beall, Andrew Forsman et al. (+10 more)

We present the fabrication and characterization of the first silicon-platelet feedhorn arrays produced using laser micromachining. First, we present a demonstration of the technology for the millimeter-wave band of 80~GHz to 170~GHz, i.e. covering the 90/150~GHz bands typical of CMB experiments. Next, we expand the technology to large-scale production on 150~mm wafers and demonstrate operation at submillimeter wavelengths. This feedhorn array is optimized for operation in a band centered at 350~GHz (330~GHz to 370~GHz) and is being deployed as one of the focal plane elements of the CCAT 350~GHz module of Prime-Cam. We present the design and fabrication processes for these feedhorn arrays and compare the optical performance directly to simulation and to feedhorns of identical design but produced using traditional deep reactive-ion etching (DRIE). We conclude with a discussion of future expansions of this technology, including the potential of sidewall control and using thicker (and thus fewer) wafers, which could significantly reduce production costs and labor.
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All authors Jason E. Austermann, James Beall, Andrew Forsman, Haibo Huang, Johannes Hubmayr, Matthew A. Koc, Jeff van Lanen, Pavel Lapa, Josh Raimist, Sara M. Simon, Jordan Stutz, Anatolios Tambazidis, Joel N. Ullom

Instrumentation and Methods for Astrophysics

Don't Cut Corners: How Training Outside the Prior Makes Simulation-Based Inference More Robust

Chaipat Tirapongprasert and Matthew Ho

Large astrophysical simulation campaigns often generate training data by sampling parameters across a Uniform prior box. Due to the proposal's sharp edge, neural posterior estimators struggle to learn accurate approximations near the boundaries. We propose Tailed-Uniform, a family of hybrid proposal distributions for sampling training simulations for robust simulation-based inference. By padding the original hard-truncated training box with decaying tails, Tailed-Uniform-trained networks yield more accurate posteriors near and beyond the edges. We demonstrate these improvements on a family of tail shapes, including a widened Uniform box as a control. Our results suggest that additional simulations near the prior boundary better constrain the networks as it approaches the edge of the training box, even for Uniform assumed priors. We show these advantages on a toy problem and cosmological parameter inference from the matter power spectrum. These benefits increase in high dimensions, where boundaries dominate parameter space volume.
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Instrumentation and Methods for Astrophysics

LIGO Detector Characterization in the Second and Third Parts of the Fourth Observing Run

J. Glanzer, A. F. Helmling-Cornell, A. Calafat et al. (+244 more)

LIGO detector characterization efforts enabled the confident detection of gravitational waves from hundreds of compact binary coalescences during the fourth observing run. Reliable production of high quality detector data and rapid noise mitigation efforts allow the extraction of the most in-depth knowledge of gravitational wave sources and their progenitors. In this paper we describe LIGO detector characterization activities during the second and third parts of O4-O4b and O4c. We summarize changes in detector configuration and performance at the LIGO Hanford and LIGO Livingston Observatories between the end of the first part of O4a and the end of O4c, including upgrades made during the commissioning break preceding O4b and during repairs performed in O4c. We describe instrumental investigations carried out at both sites designed to understand and subsequently mitigate the effect on detector sensitivity of transient glitches, narrowband spectral lines, and vibration-driven noise, among other data quality concerns. We then review the tools and procedures used to validate gravitational wave candidates and the data quality products thus supplied to searches for gravitational waves from compact binary coalescences and unmodeled transients, continuous gravitational waves, and the stochastic gravitational wave background. The efforts of the detector characterization group are essential for maintaining and improving the sensitivity and reliability of the LIGO detectors especially as observing runs lengthen and more events are detected. We conclude with prospects for LIGO detector characterization activities in future observing runs.
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All authors J. Glanzer, A. F. Helmling-Cornell, A. Calafat, S. R. Callos, E. Capote, A. Effler, T. A. Ferreira, E. Goetz, A. M. Knee, J. R. Mérou, D. Malakar, B. Mannix, D. Nandi, K. Pham, R. M. S. Schofield, P. Sharma, Z. Yarbrough, N. Arnaud, B. K. Berger, K. Burtnyk, C. M. Compton, G. Connolly, D. Davis, F. Di Renzo, G. Grant, J. C. Martins, G. Mo, A. Neunzert, L. K. Nuttall, J. Oberling, J. R. Olson, S. Soni, M. Trevor, R. Abbott, I. Abouelfettouh, R. X. Adhikari, A. Ahuja, S. Álvarez-López, A. Ananyeva, S. Appert, S. K. Apple, K. Arai, J. Areeda, N. Aritomi, S. M. Aston, M. Ball, S. W. Ballmer, D. Barker, L. Barsotti, J. Betzwieser, Z. S. Bhalla, D. Bhattacharjee, G. Billingsley, S. Biscans, C. D. Blair, N. Bode, E. Bonilla, V. Bossilkov, A. Branch, A. F. Brooks, D. D. Brown, R. Bruntz, J. Bryant, C. Cahillane, H. Cao, C. Chatterjee, N. Christensen, F. Clara, J. Collins, R. Cottingham, D. C. Coyne, R. Crouch, J. Csizmazia, A. Cumming, L. P. Dartez, N. Demos, E. Dohmen, K. L. Dooley, J. C. Driggers, S. E. Dwyer, A. Ejlli, T. Etzel, M. Evans, J. Feicht, R. Frey, W. Frischhertz, P. Fritschel, V. V. Frolov, M. Fuentes-Garcia, P. Fulda, M. Fyffe, D. Ganapathy, B. Gateley, T. Gayer, J. A. Giaime, K. D. Giardina, R. Goetz, G. Gonzalez, A. W. Goodwin-Jones, S. Gras, C. Gray, D. Griffith, H. Grote, T. Guidry, J. Gurs, E. D. Hall, J. Hanks, J. Hanson, M. C. Heintze, N. A. Holland, N.-T. Howard, D. Hoyland, H. Y. Huang, B. Hughey, Y. Inoue, A. L. James, A. Jamies, K. Jani, R. Jaume, A. Jennings, W. Jia, D. H. Jones, H. B. Kabagoz, S. Kandhasamy, S. Karat, S. Karki, M. Kasprzack, K. Kawabe, N. Kijbunchoo, P. J. King, J. S. Kissel, K. Komori, A. Kontos, R. Kumar, K. Kuns, M. Landry, B. Lantz, M. Laxen, K. Lee, M. Lesovsky, F. Llamas Villarreal, E. Lofquist-Fabris, M. Lormand, B. R. Lott, H. A. Loughlin, R. Macas, M. MacInnis, C. N. Makarem, G. L. Mansell, R. M. Martin, K. Mason, F. Matichard, N. Mavalvala, N. Maxwell, G. McCarrol, R. McCarthy, D. E. McClelland, S. McCormick, J. McIver, R. McNeil, T. McRae, F. Mera, E. L. Merilh, F. Meylahn, R. Mittleman, S. Mohan S, D. Moraru, G. Moreno, A. Mullavey, M. Nakano, T. J. N. Nelson, S. A. Nichols, J. Notte, T. O'Hanlon, R. Oram, C. Osthelder, D. J. Ottaway, H. Overmier, W. Parker, O. Patane, A. Pele, S. Perry, H. Pham, M. Pirello, J. Pullin, V. Quetschke, K. E. Ramirez, K. Ransom, J. Reyes, J. W. Richardson, K. Riles, M. Robinson, J. G. Rollins, C. L. Romel, J. H. Romie, M. P. Ross, B. I. Rotimi, K. Ryan, T. Sadecki, A. Sanchez, E. J. Sanchez, L. E. Sanchez, R. L. Savage, D. Schaetzl, M. G. Schiworski, R. Schnabel, E. Schwartz, D. Sellers, T. Shaffer, R. W. Short, D. Sigg, B. J. J. Slagmolen, J. R. Smith, C. Soike, V. Srivastava, T. Starkman, L. Sun, D. B. Tanner, J. Tasson, M. Thomas, P. Thomas, K. A. Thorne, E. M. Todd, M. R. Todd, C. I. Torrie, G. Traylor, A. S. Ubhi, R. P. Udall, G. Vajente, J. Vanosky, A. Vecchio, P. J. Veitch, A. M. Vibhute, E. R. G. von Reis, J. Warner, B. Weaver, R. Weiss, C. Whittle, P. Wilcox, B. Willke, C. C. Wipf, J. L. Wright, V. A. Xu, H. Yamamoto, L. Zhang, Z. Zhang, M. E. Zucker

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

The Shape of the Vertical Action Distribution Locates the Scatterers that Heat the Galactic Disc

Yuan-Sen Ting and Hans-Walter Rix

The Milky Way's stellar disc is thicker than the cold gas layer from which its stars form. What scatters stars onto orbits with greater vertical motion remains unresolved. Scatterers could fill the disc volume, as bending waves or dark substructure would, or could be confined to the midplane, as giant molecular clouds are. Scattering from a midplane layer occurs only during the fast plane-crossing phase and becomes less effective as that speed increases, whereas a volume-filling perturbation remains effective near the slow turning points. We derive the distribution of vertical action this leaves behind, for any height distribution of scatterers. The geometry turns out to enter only through the logarithmic slope of the diffusivity in action, $D\propto J_z^{b}$, and solving the Fokker-Planck equation gives $p(J_z)\propto\exp[-(J_z/J_0)^{2-b}]$. Scatterers that fill the volume give $b=1$ and an exponential, a thin layer at the midplane gives $b=1/2$ and a sharper cutoff: the shape of $p(J_z)$ records where the scatterers sit, the growth of its scale how strongly they scatter. We fit this model to 7589 low-$\alpha$ red clump stars of Ting & Rix (2019) between 5 and 10 kpc and 2 and 8 Gyr old, leaving the heating history free. This yields $b=0.51^{+0.06}_{-0.07}$, consistent with the thin-layer prediction but not the volume-filling one. Comparing the 2-4 Gyr heating amplitude with the present molecular surface density gives an effective scatterer mass of $2.7\times10^{6}\,M_\odot$. Older stars have experienced more of the Galaxy's gas-richer past; correcting for that history brings all four age bins to $(1.9-2.8)\times10^{6}\,M_\odot$, inside the range cloud catalogues and mass functions give. The Milky Way's disc is heated near the plane, by an evolving population of objects of giant-molecular-cloud mass.
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Instrumentation and Methods for Astrophysics

Voltage-to-temperature calibration of the High Altitude THz Solar telescope acquisition system

Gedeane G.S. Kenshima, Daniel R. Sousa, Tiago Giorgetti et al. (+2 more)

The THz range has been under-explored for solar astronomy, mainly due to technological limitations. Only recently, a few new telescopes, such as the High Altitude Terahertz Solar (HATS) photometer, have been monitoring the solar activity in this range of the spectrum. This paper presents the experimental characterization and voltage-to-temperature calibration of the HATS acquisition system. HATS uses a Golay cell for capturing the incoming radiation, modulated by a 20 Hz fork chopper. The amplitude of the signal is then obtained at predetermined time intervals by applying a windowing function and an FFT to the signal. To characterize this acquisition system, a blackbody calibrator, with temperatures varying from 100 to 500 C (373.15 K to 648.15 K), was used as a THz source, and two signal recovery methodologies were compared: sinusoidal curve fitting and FFT combined with six windowing functions (rectangular, Hamming, Hann, Barlett, Blackman, and Flat Top). Our quantitative results demonstrate high linearity in the system's response over the input source's temperature range, with the Hamming window achieving the highest precision, yielding a Root Mean Square Error (RMSE) of 15.48 and a calibration temperature-to-voltage factor of 10.32 +- 0.13 mV/K. In contrast, the Bartlett window presented the highest error (RMSE 16.02). The choice of windowing function had only a minor effect on the calibration factors, which ranged from 10.32 to 10.43 mV/K, all within the experimental uncertainties. Beyond solar photometry, the signal modulation and windowing concepts established here are highly applicable to other fields requiring high-sensitivity thermal detection, such as industrial pyrometry for high-temperature manufacturing, environmental monitoring of atmospheric water vapor, and the development of medical imaging systems based on Terahertz radiation for non-invasive tissue analysis.
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All authors Gedeane G.S. Kenshima, Daniel R. Sousa, Tiago Giorgetti, Paulo J. A. Simões, C. Guillermo Giménez de Castro

Instrumentation and Methods for Astrophysics

Updates to WFC3/UVIS Encircled Energy Values in Select Filters

Anne O'Connor, Jennifer Mack and Varun Bajaj

We present updated encircled energy (EE) curves for a subset of UVIS filters. These are derived from a reanalysis of the drizzled Point Spread Function (PSF) data underlying the current EE calibration together with new measurements from deep observations of the PSF wings. Improved centroiding and analysis techniques applied to the drizzled PSFs produce more accurate EE values at small radii ($r \le 10$ pixels), bringing the results into closer agreement with a large archival PSF study (Huynh et al. 2025). At large radii, we leverage deep observations of the PSF wings in six filters and compare the fraction of light between 2" and 6" with predictions from an optical model of the PSF (Hartig 2009). For filters with pivot wavelengths $ \gtrsim{4000} \mathrm{\mathring{A}}$, the model agrees with the empirical data, but over-estimates the EE for UV filters by $\sim0.5$% at 2". The revised EE solutions affect the UVIS zeropoints, which are derived from aperture photometry in a 0.4" (10 pixel) radius and corrected to 6" using EE tables (Calamida et al. 2022). Overall, the impact is small; the EE at 0.4" is larger by $ \gtrsim{0.5}$ % (0.005 mag) for several filters (F218W, F225W, F275W, F775W, F814W, F845M), especially for UVIS2. In contrast, the EE value is generally smaller at 0.4" for long-pass filters (F200LP, F350LP, F850LP), with F850LP differing by $\sim2 $ % (0.02 mag). Updated EE tables will be delivered together with a revised set of UVIS inverse sensitivity tables and zeropoints later in 2026. In the interim, we provide EE tables for commonly used filters in Appendix A.
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Instrumentation and Methods for Astrophysics

Automation and Modernisation of Legacy BiSON Solar Observatories with the BiSON:NG Platform

S. J. Hale, E.Murray, W. J. Chaplin et al. (+4 more)

The Birmingham Solar Oscillations Network (BiSON) provides long-term, high-precision Sun-as-a-star radial-velocity observations for helioseismology. While most BiSON sites operate autonomously, two observatories at Observatorio del Teide, Tenerife, and at Mount Wilson Observatory, USA, have historically required daily on-site operation. We present the automation of these sites using the BiSON:NG next-generation observing platform, incorporating compact fibre-fed instrumentation and a modular, microservice-based control and data acquisition architecture. At both locations, new automated optical feeds and a common software framework have been deployed, enabling autonomous operation of the observing subsystems, including guiding, data acquisition, and instrument control, despite markedly different physical and operational constraints. The upgrades demonstrate that modern automation can be successfully integrated within existing and historic observatory infrastructure. Adoption of the BiSON:NG architecture reduces operational overhead, mitigates risks associated with hardware and software obsolescence, and supports sustainable operation of the network over the multi-decade timescales required for helioseismic studies. The flexibility of the architecture also provides a pathway for future deployment of additional small-footprint observatories.
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All authors S. J. Hale, E.Murray, W. J. Chaplin, Y. P. Elsworth, R. Howe, P. L. Pallé, E. J. Rhodes Jr

Instrumentation and Methods for Astrophysics

SPORE: An Event-Level Sampling Pipeline for Multi-Telescope Neutrino Astronomy

Jeffrey Lazar, Perrine Wilmet and Gwenhaël de Wasseige

We present an open-source Python package for simulating neutrino events from astrophysical point and extended sources using tabulated instrument response functions (IRFs). The package encodes three detector response components - effective area, point spread function, and energy resolution - in a selection-agnostic HDF5 format, which can represent a neutrino telescope whose response is supplied in that form, whether from a public release or a private study. Sampling algorithms cover point sources (inverse-CDF with Poisson or fixed-count modes), extended sky distributions (hierarchical inverse-CDF sampling, including full RA- and declination-dependent flux maps), and multi-detector joint analyses. We validate the framework via a round-trip consistency test using the publicly available IceCube 10-year tracks data release: the released IRFs are ingested into the package and used to generate a synthetic event set, whose declination distribution reproduces the observed one to 10-15% across the northern sky. The reconstructed-energy distribution agrees to within about a third over the bulk of the sample but exceeds the data by up to a factor of three below 600 GeV, a discrepancy we trace to the coarse true-energy binning of the public smearing matrix rather than to the sampling: an independent forward fold of the same IRFs reproduces it. We further compare against the IceCube HESE 7.5-year public data release: the sampled deposited-energy spectrum tracks the published best-fit expectation, and the observed data fall within the goodness-of-fit distribution built from 1,000 sampled pseudo-experiments, though on its well-fitting side, as expected for an expectation that was itself fit to those data.
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Instrumentation and Methods for Astrophysics · Cross-listed from gr-qc

Taiji Resolving Power for the Transverse Scalar Mode of Gravitational Waves

Bo-Xuan Ge and Zhoujian Cao

We investigate how small a co-propagating transverse-scalar component can be resolved by Taiji in an already identified bright tensor chirp. Using a source-tracked tensor-null response, we formulate the problem in terms of the minimum resolvable scalar strain fraction and evaluate it over the sky. For a one-year benchmark chirp with tensor signal-to-noise ratio $\rho_T=1000$, we find that Taiji can rule out transverse-scalar strain fractions $\epsilon_b\gtrsim0.532\%$ at the all-sky median level. The threshold scales as $\epsilon_{b,\min}\propto\rho_T^{-1}$, so brighter tensor events can probe correspondingly smaller scalar fractions. We further find that this sub-percent resolving power remains predictable under small source-parameter mismatches through the associated tensor-leakage structure.
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Instrumentation and Methods for Astrophysics

LIGO A$^\sharp$: Detector Design and Science Prospects Beyond A+

L. Sun, K. Kuns, B. J. J. Slagmolen et al. (+1153 more)

We present the LIGO A$^\sharp$ detector concept, an upgrade for the LIGO observatories based on room-temperature interferometers beyond the fifth observing run (O5). Building on the A+ sensitivity, A$^\sharp$ targets broadband sensitivity improvements through heavier test masses, improved suspensions and seismic isolation, increased arm-cavity power, enhanced frequency-dependent squeezing, reduced coating thermal noise considering two scenarios, and improved control of mechanical motion and optical modes. We describe the principal design choices, projected noise performance, and corresponding astrophysical prospects. LIGO A$^\sharp$ substantially increases compact-binary detection rates, strengthens population inference, and improves both early-warning times and localization for binary neutron star mergers. The improved sensitivity enables more detailed studies of compact-binary coalescences, including higher-order multipoles, intermediate-mass black holes, remnant black hole ringdown, and the neutron star equation of state. It also broadens the discovery potential for new gravitational-wave sources such as continuous waves and bursts, should enable detection of the stochastic background from compact binary mergers if it remains undetected after O5, and strengthens the role of gravitational-wave detectors as probes of fundamental physics. We discuss key technical challenges and the role of A$^\sharp$ as both a major scientific upgrade for the 2030s and a technology pathfinder for next-generation gravitational-wave observatories, such as Cosmic Explorer.
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All authors L. Sun, K. Kuns, B. J. J. Slagmolen, P. Fritschel, P. Schmidt, B. T. Lantz, S. S. Y. Chua, Divyajyoti, S. W. Ballmer, M. A. Barton, A. V. Cumming, K. L. Dooley, J. C. Driggers, A. Effler, M. Evans, B. Farr, G. González, N. Lu, D. J. Ottaway, C. Palomba, O. J. Piccinni, G. Pratten, S. Raja, A. P. Subhash, P. J. Sutton, K. Toland, R. L. Ward, A. G. Abac, I. Abouelfettouh, K. Ackley, A. Adam, S. Adhicary, D. Adhikari, R. X. Adhikari, V. K. Adkins, S. Afroz, M. Agathos, N. Aggarwal, S. Aggarwal, O. D. Aguiar, P. Ajith, L. Albers, S. Al-Kershi, S. Al-Shammari, J. A. Alvarez, S. Alvarez-Lopez, O. Amarasinghe, A. Amato, S. An, A. B. Anand, C. Anand, A. Ananyeva, S. B. Anderson, W. G. Anderson, F. Andrade-Oliveira, M. Andrés-Carcasona, J. L. Andrey, T. Andric, J. Anglin, J. Anna, J. M. Antelis, L. V. da Conceição, T. Aoki, E. Z. Appavuravther, E. A. Appelt, S. Appert, S. K. Apple, K. Arai, M. C. Araya, J. S. Areeda, M. Ramos Arevalo, S. Armstrong, M. Arogeti, S. M. Aronson, K. G. Arun, G. Ashton, S. M. Aston, K. AultONeal, G. Avallone, E. A. Avila, C. Badger, S. Bae, K. A. Baker, T. Baker, M. Ball, S. Banagiri, D. Bankar, T. M. Baptiste, P. Baral, J. C. Barayoga, K. Baric, B. C. Barish, D. Barker, N. Barman, B. Barr, M. Barrios, L. Barsotti, I. Bartos, A. Basalaev, R. Bassiri, J. C. Bayley, A. C. Baylor, P. A. Baynard II, B. Becher, V. M. Bedakihale, A. S. Bell, D. S. Bellie, W. Benoit, F. Bergamin, B. K. Berger, M. Beroiz, C. P. L. Berry, I. Berry, J. Betzwieser, D. Beveridge, N. Bevins, R. Bhandare, R. Bhatt, A. Bhattacharjee, D. Bhattacharjee, S. Bhattacharyya, S. Bhaumik, I. A. Bilenko, G. Billingsley, S. Bini, O. Birnholtz, S. Biscoveanu, A. Bisht, S. Blaber, J. K. Blackburn, L. A. Blagg, C. D. Blair, D. G. Blair, N. Bode, N. Boettner, P. Bogdan, G. N. Bolingbroke, L. D. Bonavena, V. A. Bonhomme, E. Bonilla, M. S. Bonilla, A. Bonino, A. Borchers, S. Bose, V. Bossilkov, T. D. Boybeyi, M. Boyle, M. J. Brady, P. R. Brady, A. Branch, M. Brinkmann, P. Brockill, E. Brockmueller, A. F. Brooks, D. D. Brown, S. Brunett, R. Bruntz, J. Bryant, Y. Bu, A. Buonanno, K. Burtnyk, J. Calderón Bustillo, R. L. Byer, V. A. Cáceres-Barbosa, L. Cadonati, C. Cahillane, A. Calafat, J. D. Callaghan, T. A. Callister, S. R. Callos, V. Cantory, H. Cao, L. A. Capistran, E. Capote, C. Capuano, K. J. Cardona-Martínez, M. Carlassara, J. Yébana Carrilero, G. Carrillo, G. Carullo, S. Caudill, M. Cavaglià, A. Ceja, N. Chabbra, A. Chakraborty, P. Chakraborty, S. Chakraborty, C. Chan, J. C. L. Chan, M. Chan, K. Chang, S. Chao, P. Charlton, C. Chatterjee, Debarati Chatterjee, Deep Chatterjee, M. Chaturvedi, A. Chen, H. Y. Chen, S. Chen, Yanbei Chen, Yiwen Chen, G. Cheng, H. P. Cheng, T. Cheunchitra, H. T. Cheung, S. Y. Cheung, G. Chiarini, M. Chicoine, D. Chintala, S. Choudhary, N. Christensen, Y. K. Chu, B. Cirok, F. Clara, J. A. Clark, T. A. Clarke, A. Claveus, M. R. Claypool, S. M. Clyne, D. E. Cohen, E. Colangeli, O. Cole, G. D. Cole, M. Colleoni, C. G. Collette, J. Collins, S. Colloms, C. M. Compton, G. Connolly, T. R. Corbitt, N. J. Cornish, A. Corsi, L. Cotnoir, R. Cottingham, J. A. Cotturone, M. W. Coughlin, P. Couvares, R. Coyne, J. D. E. Creighton, T. D. Creighton, S. Crook, R. Crouch, J. Csizmazia, T. J. Cullen, Y. Dang, O. Danner, K. Danzmann, K. E. Darroch, C. Darsow-Fromm, L. P. Dartez, R. Das, S. Das, A. Dasgupta, I. Dave, A. Davenport, T. F. Davies, D. Davis, M. C. Davis, E. J. Daw, M. Dax, E. deBruin, M. Deenadayalan, O. M. del Rio, N. Demos, T. Dent, N. DePergola, E. K. Derrick, M. Desai, D. DeSantis, S. Deshmukh, V. Deshmukh, S. Determan, A. Dhani, R. Dhatri, R. Dhurkunde, R. Diab, M. C. Díaz, T. Dietrich, C. Di Fronzo, A. Dmitriev, J. P. Docherty, Z. Doctor, N. Doerksen, E. Dohmen, A. Doke, F. Donovan, S. Doravari, F. Dosopoulou, R. S. Dumbreck, S. Dwivedi, S. E. Dwyer, C. Eassa, M. Eberhardt, M. Ebersold, M. Ebiri, T. Eckhardt, G. Eddolls, J. Eichholz, M. Emma, R. Enficiaud, R. Espinosa, R. C. Essick, H. Estellés, T. Etzel, T. Evstafyeva, J. M. Ezquiaga, S. Fairhurst, X. Fan, A. M. Farah, W. M. Farr, M. Favata, M. Fazio, J. Feicht, M. M. Fejer, J.-N. Feldhusen, J. Fernandes, D. Fernando, T. A. Ferreira, M. Ferrer-Martinez, M. Fishbach, R. P. Fisher, S. K. Fitzgerald, B. Flanagan, S. M. Fleischer, L. S. Fleming, E. Floden, H. Fong, F. Fontinele-Nunes, C. Foo, B. Fornal, P. W. F. Forsyth, A. Franco-Ordovas, J. P. Freed, Z. Frei, R. Frey, W. Frischhertz, V. V. Frolov, M. Fuentes-Garcia, P. Fulda, M. Fyffe, J. R. Gair, V. Galdi, A. Gamboa, S. Gamoji, A. Ganguly, C. García-Quirós, J. W. Gardner, A. Garron, P. A. Garver, V. Gayathri, T. Gayer, J. George, R. George, D. George, O. Gerberding, L. Gergely, Sayantan Ghosh, Shaon Ghosh, Shrobana Ghosh, Suprovo Ghosh, Tathagata Ghosh, J. A. Giaime, K. D. Giardina, D. R. Gibson, C. Gier, J. Glanzer, J. Godfrey, R. V. Godley, O. Godwin, A. S. Goettel, E. Goetz, J. Golomb, P. Goodarzi, S. R. Goode, S. M. Goss-Grubbs, D. W. Gould, K. Govorkova, V. Graham, A. E. Granados, M. Granata, V. Granata, S. Gras, P. Grassia, C. Gray, R. Gray, K. Gray, L. Green, S. R. Green, A. M. Gretarsson, E. M. Gretarsson, D. Griffith, H. Grote, S. Grunewald, A. G. Guerrero, T. Guidry, H. K. Gulati, H. Guo, W. Guo, A. Gupta, I. Gupta, N. C. Gupta, S. K. Gupta, V. Gupta, N. Gupte, N. Guttman, F. Guzman, M. Haberland, E. D. Hall, E. Z. Hamilton, G. Hammond, J. Hanks, C. Hanna, M. D. Hannam, O. A. Hannuksela, H. Hansen, J. Hanson, A. R. Hardison, K. Haris, I. Harley-Trochimczyk, G. M. Harry, I. W. Harry, C.-J. Haster, K. Haughian, J. Hedberg, A. Heffernan, M. C. Heintze, J. Heinzel, F. Hellman, A. F. Helmling-Cornell, O. Henderson-Sapir, M. Hendry, I. S. Heng, M. H. Hennig, C. Henshaw, A. Heranval, M. Heurs, A. L. Hewitt, J. Heyns, D. Hickey, M. Hill, S. Hill, N. A. Holland, K. Holley-Bockelmann, I. J. Hollows, D. E. Holz, K. M. Hoops, M. E. Hoque, D. J. Horton-Bailey, J. Hough, S. Hourihane, N. T. Howard, E. J. Howell, C. G. Hoy, P. Hsi, H. Y. Huang, Y. Huang, A. D. Huddart, B. Hughey, S. Husa, G. A. Iandolo, Y. Inoue, J. Irwin, T. Ishikawa, M. Isi, K. S. Isleif, S. Iwaguchi, M. M. Iwaya, B. R. Iyer, S. J. Jadhav, S. P. Jadhav, K. Jain, A. L. James, K. Jani, S. Jani, N. N. Janthalur, R. Jaume, W. Javed, M. Jensen, W. Jia, J. Jiang, S.-J. Jin, G. R. Johns, N. A. Johnson, M. C. Johnston, R. Johnston, N. Johny, D. H. Jones, D. I. Jones, R. Jones, P. Joshi, S. K. Joshi, J. Ju, L. Ju, I. L. Juarez-Reyes, H. B. Kabagoz, V. Kalogera, M. Kalomenopoulos, S. Kandhasamy, G. Kang, M. Kang, J. B. Kanner, S. J. Kapadia, D. P. Kapasi, A. S. Karia, R. Kashyap, M. Kasprzack, E. Katsavounidis, W. Katzman, R. Kaushik, K. Kawabe, S. Kawamura, D. Keitel, S. A. Kemper, L. J. Kemperman, J. Kennington, R. Kesharwani, J. S. Key, R. Khadela, S. S. Khadkikar, F. Y. Khalili, C. Khamar, F. Khan, M. Khursheed, N. M. Khusid, C. Kim, J. C. Kim, K. Kim, M. H. Kim, Y.-M. Kim, C. Kimball, K. Kimes, M. Kinnear, J. S. Kissel, S. Klimenko, A. M. Knee, N. Knust, S. M. Koehlenbeck, K. Kokeyama, P. Kolitsidou, K. Kompanets, A. K. H. Kong, A. Kontos, K. Kopczuk, L. M. Koponen, M. Korobko, X. Kou, N. Kouvatsos, D. B. Kozak, V. Kringel, N. V. Krishnendu, S. Kroker, K. Kruska, G. Kuehn, D. Kukla, Achal Kumar, Anil Kumar, Dhruv Kumar, Praveen Kumar, Prayush Kumar, Rahul Kumar, Rakesh Kumar, Ravi Kumar, V. Kumar, N. Kuntimaddi, K. Kwan, G. Lacaille, D. Laghi, A. H. Laity, E. Lalande, S. Lalvani, M. Landry, R. N. Lang, A. Lange, R. Langgin, I. La Rosa, O. Laske, P. D. Lasky, J. Lawrence, M. Laxen, A. Lazzarini, L. Leali, Y. K. Lecoeuche, J. Lee, K. Lee, R. Lee, S. Lee, Y. Lee, I. N. Legred, J. Lehmann, L. Lehner, M. Lesovsky, Y. Levin, K. Leyde, X. Li, Y. Li, Z. Li, Q. Liang, F. Lin, C. Lindsay, S. D. Linker, A. Liu, Jian Liu, S. Liu, J. Llobera-Querol, R. K. L. Lo, S. C. G. Loggins, L. T. London, R. Rodriguez Lopez, A. Lorenzo-Medina, M. Lormand, T. P. Lott IV, J. D. Lough, H. A. Loughlin, C. O. Lousto, N. K. Y. Low, H. Lück, O. Lukina, A. P. Lundgren, A. W. Lussier, X. Ma, M. Ma'arif, S. MacBride, I. MacLaren, D. M. Macleod, I. A. O. MacMillan, S. S. Magare, R. M. Magee, E. Maggio, P. Mahapatra, M. Mahesh, S. Majhi, C. N. Makarem, E. Makelele, N. Malagon, D. Malakar, J. A. Malaquias-Reis, U. Mali, S. Maliakal, A. Malik, L. Mallick, A.-K. Malz, V. Mandic, Z. Mangi, B. Mannix, G. L. Mansell, M. Manske, J. Mark, A. S. Markosyan, J. Markus, E. Maros, I. W. Martin, R. M. Martin, B. B. Martinez, J. C. Martins, D. V. Martynov, E. J. Marx, M. Masso-Reid, T. Masters, M. Matiushechkina, A. Matte-Landry, N. Mavalvala, N. Maxwell, A. McCann, G. McCarrol, R. McCarthy, D. E. McClelland, S. McCormick, L. McCuller, L. I. McDermott, C. McElhenny, G. I. McGhee, K. B. M. McGowan, J. McIver, A. McLeod, I. McMahon, T. McRae, R. McTeague, K. McWhirter, D. Meacher, B. N. Meagher, R. Mechum, M. Mehmet, R. M. Mehta, A. Melatos, C. S. Menoni, R. A. Mercer, K. Merfeld, E. L. Merilh, J. R. Mérou, C. Messick, F. Meylahn, H. Miao, C. Michel, H. Middleton, D. P. Mihaylov, S. J. Miller, M. Millhouse, A. Mishra, C. Mishra, T. Mishra, A. Mitchell, J. G. Mitchell, O. Mitchem, S. Mitra, V. P. Mitrofanov, R. Mittleman, G. Mo, S. R. P. Mohapatra, M. Molina-Ruiz, M. Mondin, C. J. Moore, D. Moraru, A. More, S. More, C. Moreno, E. A. Moreno, G. Moreno, C. Morgan, M. Mould, C. M. Mow-Lowry, Arunava Mukherjee, D. Mukherjee, Samanwaya Mukherjee, Soma Mukherjee, Subroto Mukherjee, Suvodip Mukherjee, N. Mukund, A. Mullavey, C. L. Mungioli, P. G. Murray, S. Muusse, S. A. Vallejo-Peña, N. Nagarajan, A. Nakamura, M. Nakano, D. Nandi, S. U. Naqvi, P. Narayan, R. K. Nayak, J. Neeson, A. Nela, C. Nelle, A. Nelson, T. J. N. Nelson, A. Neunzert, M. Newell, S. Ng, A. B. Nielsen, W. Niu, J. Noller, M. Norman, C. North, A. Numic, G. Nurbek, L. K. Nuttall, J. Oberling, C. E. Ochoa, C. O'Connor, J. O'Dell, E. Oelker, J. J. Oh, T. O'Hanlon, F. Ohme, I. Oke, R. Omer, N. O'Neill, P. Ophardt, R. J. Oram, B. O'Reilly, R. O'Shaughnessy, J. Ostrovska, A. Osumi, I. Ota, G. Othman, H. Overmier, B. J. Owen, A. E. Pace, A. Pai, S. Pal, M. Pálfi, H. Pan, J. Pan, P. K. Panda, Shiksha Pandey, Swadha Pandey, B. C. Pant, F. H. Panther, A. Papadopoulos, E. E. Papalexakis, J. Park, W. Parker, G. Pascale, L. Passenger, O. Patane, A. V. Patel, L. Pathak, A. Patra, B. G. Patterson, K. Paul, S. Paul, E. Payne, T. Pearce, M. Pedraza, A. Pele, X. Peng, Y. Peng, S. Penn, S. Petracca, H. P. Pfeiffer, H. Pham, K. A. Pham, K. S. Phukon, H. Phurailatpam, A. Pied, V. Pierro, B. Pillon, I. M. Pinto, B. J. Piotrzkowski, M. Pirello, M. D. Pitkin, M. L. Planas, C. Plunkett, L. Pompili, J. Poon, A. S. Porter, C. Posnansky, J. Powell, G. S. Prabhu, A. K. Prajapati, K. Prasai, R. Prasanna, P. Prasia, A. Puecher, J. Pullin, M. Pürrer, H. Qi, M. Qiao, J. Qin, V. Quetschke, P. J. Quinonez, R. Rading, C. Rajan, B. Rajbhandari, A. Kulur Ramamohan, K. E. Ramirez, A. Ramos-Buades, S. Ranjan, M. Ranjbar, K. Ransom, B. Ratto, A. Ravichandran, A. Ray, V. Raymond, J. Read, J. Redepenning, J. Regan, T. Reichardt, S. Reid, C. Reissel, D. H. Reitze, A. I. Renzini, J. Rice, J. W. Richardson, M. L. Richardson, K. Riles, H. K. Riley, J. D. H. Rivero, M. Robinson, J. Rodriguez, J. G. Rollins, A. E. Romano, I. M. Romero-Shaw, J. H. Romie, S. Ronchini, T. J. Roocke, T. J. Rosauer, C. A. Rose, M. P. Ross, M. Rossello-Sastre, S. Rowan, K. Rowlands, P. Dutta Roy, S. K. Roy, T. RoyChowdhury, G. H. Ruiz, K. Ruiz-Rocha, V. Russ, S. M. S., S. Sachdev, T. Sadecki, S. Safi-Harb, M. R. Raj Sah, M. Sakellariadou, S. Sakon, F. Salces-Carcoba, M. Saleem, S. U. Salunkhe, A. Salvarese, P. M. Samir, A. Sanchez, E. J. Sanchez, J. Sanchez, D. Sanchez-Cid, J. R. Sanders, E. M. Sänger, J. Sanjuan, E. Sapkin, T. R. Saravanan, P. Sarkar, A. Sasli, B. S. Sathyaprakash, O. Sauter, R. L. Savage, T. Savicheva, H. L. Sawant, D. Schaetzl, M. Scheel, L. M. Scheel, A. Schiebelbein, F. Schiettekatte, M. G. Schiworski, K. Schluterman, R. Schnabel, M. Schneewind, R. M. S. Schofield, B. W. Schulte, B. F. Schutz, E. Schwartz, J. Scott, S. M. Scott, R. M. Sedas, T. C. Seetharamu, D. Sellers, E. G. Seo, G. Seong, C. K. Sethi, T. Shaffer, U. S. Shah, M. A. Shaikh, J. Sharkey, A. K. Sharma, Preeti Sharma, Priyanka Sharma, Sushant Sharma-Chaudhary, P. Shawhan, T. Shen, S. Shirke, D. H. Shoemaker, D. M. Shoemaker, R. W. Short, S. ShyamSundar, H. Siegel, V. Sierra, D. Sigg, L. Silenzi, M. Simmonds, L. P. Singer, A. Singh, D. Singh, M. K. Singh, N. Singh, H. Singh, M. R. Sinha, A. M. Sintes, V. Skliris, T. J. Slaven-Blair, J. Smetana, D. A. Smith, J. R. Smith, J. Smith, W. J. Smith, M. Soares-Santos, S. Soni, N. E. Sovitzky, V. Spagnuolo, A. P. Spencer, A. K. Srivastava, F. Stachurski, V. V. Stanford, A. Stanton, N. Steinle, J. Steinlechner, C. Stephens, M. StPierre, J. Stremiz, M. D. Strong, A. Strunk, S. Chalathadka Subrahmanya, L. Suleiman, K. D. Sullivan, J. Sun, S. Sunil, S. C. Tait, S. Takano, C. Talbot, D. Tanabe, S. Tanioka, D. B. Tanner, W. Tanner, L. Tao, R. D. Tapia, J. D. Tasson, J. G. Tau, A. Tejera, J. G. Temple, Y. Teng, H. Themann, M. P. Thirugnanasambandam, L. M. Thomas, M. Thomas, P. Thomas, J. E. Thompson, S. R. Thondapu, E. Thrane, A. Tiwari, P. Tiwari, S. Tiwari, V. Tiwari, M. R. Todd, A. M. Toivonen, V. Tommasini, H. Tong, C. I. Torrie, G. Traylor, L. Traylor, M. Trevor, A. Tripathee, R. J. Trudeau, T. Tsang, K. Tsuji, L. Tsukada, A. Tuci, A. S. Ubhi, R. P. Udall, V. Undheim, V. Upadhyaya, L. E. Uronen, H. Vahlbruch, G. Vajente, J. Valencia, M. Valentini, J. van Dongen, K. Vandra, M. VanDyke, J. Vanier, J. Vanosky, A. F. Vargas, V. Varma, A. Vecchio, J. Veitch, P. J. Veitch, B. Verma, Y. Verma, S. M. Vermeulen, F. A. Ramis Vidal, S. Vidyant, A. D. Viets, A. Vijaykumar, A. Vilkha, F. Llamas Villarreal, E. T. Vincent, S. Vitale, N. Vithanachchi, A. Vives, L. Vizmeg, B. Vizzone, D. Voigt, E. R. G. von Reis, J. S. A. von Wrangel, W. E. Vossius, L. Vujeva, S. P. Vyatchanin, J. Wack, L. E. Wade, M. Wade, A. Wade, K. J. Wagner, L. Wallace, W. H. Wang, Y. F. Wang, Z. Wang, P. Wang, J. Warner, N. Y. Washington, B. Weaver, S. A. Webster, N. L. Weickhardt, M. Weinert, A. J. Weinstein, O. Weisenberger, R. Weiss, L. Wen, K. Wette, C. Wheeler, J. T. Whelan, B. F. Whiting, E. G. Wickens, D. Wilken, B. M. Williams, D. Williams, M. J. Williams, N. S. Williams, J. L. Willis, B. Willke, C. W. Winborn, A. Wingfield, J. Winterflood, C. C. Wipf, G. Woan, N. E. Wolfe, H. T. Wong, J. L. Wright, B. Wu, D. S. Wu, K. Wu, E. Wuchner, D. M. Wysocki, Y. Xia, V. A. Xu, Y. Xu, M. Ben Yaala, H. Yamamoto, T. Yan, H. Yang, K. Z. Yang, Z. Yarbrough, A. B. Yelikar, X. Yin, M. Yoshihara, S. Yuan, M. Zanolin, M. Zeeshan, M. Zevin, H. Zhang, L. Zhang, N. Zhang, R. Zhang, T. Zhang, C. Zhao, Y. Zhao, L.-M. Zheng, Y. Zheng, H. Zhong, H. Zhou, H. O. Zhu, Z. Zhu, D. Z. Zieba, A. B. Zimmerman, M. E. Zucker, R. Arès, J. J. Carter, S. J. Madden, K. McKenzie, E. R. Rees, B. Shapiro

Instrumentation and Methods for Astrophysics

Towards Genuine Coexistence: Per-Satellite Emission and Radiation Limits to Protect Radio Astronomy and Geodetic VLBI at 1-14 GHz from Satellite Constellations

Balthasar Indermuehle, Lucia McCallum, Emma van der Wateren et al. (+7 more)

Geodetic very long baseline interferometry (VLBI) is a vulnerable application of the radio astronomy service (RAS): it provides the fundamental link between the celestial and terrestrial reference frames, and is the only technique that uniquely determines UT1-UTC. The next-generation geodetic VLBI Global Observing System (VGOS) achieves millimetre accuracy by synthesising group delay across 3-14 GHz using 32x32 MHz channels, most of which lie outside RAS primary allocations. The SNIFFLES-I survey (Indermuehle et al 2026) measured intended emissions, unwanted emissions (spurious emissions, notably harmonics), and unintended electromagnetic radiation (UEMR) of NGSO systems from 1-26 GHz. On this basis we model the equivalent power flux density (EPFD) of current and future constellations and compare against protection criteria of ITU-R RA.769. The analysis extends to frequencies without radio astronomy allocations where SNIFFLES-I made detections. For geodetic VLBI, we run a Monte-Carlo EPFD model at the AuScope VGOS stations and scale the aggregate from the present catalogued fleet (~12000 satellites) to the hundreds of thousands on file with a validated method. Inverting the EPFD analysis against the interpolated RA.769 thresholds yields maximum tolerable per-satellite levels for spurious emissions and for UEMR, expressed as a field-strength limit in dB(uV/m) at 10 m for standard-setting bodies. We treat proposed orbital-data-centres in Sun-synchronous orbit as a distinctively UEMR-dominated case. We find that already today the single-dish protection criteria are exceeded in two primary RAS bands. For geodetic VLBI, the dominant threat is spurious emission from the 2620 MHz Direct-to-device (DTD) downlink, whose second harmonic at 5240 MHz already causes at least 59% data loss today. (Abstract modified for arxiv limits)
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All authors Balthasar Indermuehle, Lucia McCallum, Emma van der Wateren, Hayo Hase, Benjamin Winkel, Liroy Lourenco, Federico Di Vruno, Michael Lindqvist, Gregory Hellbourg, Gyula Jozsa

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

Dynamic Trajectory Analysis of Meteoroids Showing Minimal Deceleration

Thomas Stevenson, Ellie Sansom, Hadrien Devillepoix et al. (+8 more)

Meteoroids decelerate and ablate as they descend through the atmosphere, however a portion of instrumentally observed meteors show little measurable deceleration and remain poorly characterised. These are referred to as minimally decelerating objects (MDOs). The traditional alpha-beta method of dynamic trajectory analysis cannot reliably determine their preatmospheric masses or rates of ablation. We present a new approach for estimating the ballistic coefficients (alpha) and mass loss parameters (beta) of MDOs, allowing their inclusion in dynamic analyses. This new method employs bulk ablation coefficients derived from instrumentally observed meteorite falls and large meteor shower bodies. It is applied to MDOs comprising approximately one-third of the Global Fireball Observatory (GFO) 2014 - 2024 dataset. Our results show that MDOs are predominantly small objects occupying a distinct region of alpha-beta space. Material types can be identified using supplementary data such as emission spectra, which we demonstrate using observations of 10 small iron meteoroids. This methodology expands the range of meteoroid populations accessible to dynamic trajectory analysis, providing new constraints on meteorite deposition and the compositional diversity of near-Earth objects.
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All authors Thomas Stevenson, Ellie Sansom, Hadrien Devillepoix, Maria Gritsevich, Anna Zappatini, Peter Jenniskens, Christopher Herd, Jonti Horner, Nick Moskovitz, Samantha Hemmelgarn, Luke Daly

Tuesday 11 August

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

Diameters and Temperatures VII: High-angular resolution measurements of Solar-type stars with the CHARA Array

Tabetha S. Boyajian, Ashley A. Elliott, Emelly D. Tiburcio et al. (+8 more)

We present interferometric measurements of angular diameters for 27 nearby solar-type stars obtained with the Precision Astronomical Visible Observations (PAVO) beam combiner at the CHARA Array. The sample spans a broad range of metallicities, includes several known exoplanet hosts, and covers evolutionary stages from the zero-age main sequence to mildly evolved subgiants. Uniform-disk and limb-darkened angular diameters were measured for each target and combined with bolometric fluxes and Gaia parallaxes to determine precise, model-independent stellar radii, effective temperatures, and luminosities. We achieve typical uncertainties of $\sim1$% in radius and $\sim1.5$% in effective temperature. Comparisons with multiple stellar evolutionary model grids yield mass and age estimates and enable assessment of grid-to-grid systematics, highlighting sensitivities to abundances, evolutionary stage, and proximity to grid boundaries. Our results provide empirical benchmarks for testing stellar evolutionary theory, refining surface brightness-color relations, and improving the characterization of exoplanet host stars.
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All authors Tabetha S. Boyajian, Ashley A. Elliott, Emelly D. Tiburcio, Kaspar von Braun, Gail Schaefer, Timothy R. White, Daniel Huber, Michael Ireland, Jeremy Jones, Tyler Ellis, Eliot Hiegel

Instrumentation and Methods for Astrophysics

Early Exploration of the Scientific Discovery Space for the Habitable Worlds Observatory

Courtney D. Dressing, Danica Adams, Evelyne Alecian et al. (+324 more)

The Habitable Worlds Observatory (HWO) is a future NASA flagship mission concept identified by the Astro2020 Decadal Survey as the highest priority for large space missions. HWO should conduct "transformative astrophysics" and search for biosignatures in the atmospheres of approximately 25 potentially Earth-like planets. To further the early-stage development of HWO, NASA formed the Science, Technology, Architecture Review Team (START). In turn, START invited the scientific community to join working groups to explore the potential discovery space. In this paper, we present 70 science cases that resulted from this process. The cases address four scientific pillars: growth of galaxies (15 cases), evolution of the elements (13 cases), solar systems in context (32 cases), and living worlds (10 cases). Combined, they would address 27 of the 30 science questions and discovery areas identified by Astro2020. The 140 observing programs needed for the 70 investigations encompass a rich variety of spectroscopic (for 87% of science cases) and photometric (for 30%) observations extending from the UV to the NIR. Additionally, high-contrast and polarimetric capabilities would be needed for 34% and 27% of science cases, respectively. Access to UV wavelengths is critical: 83% of science cases need data at wavelengths <400 nm, and 26% extend to <100 nm. In the NIR, 26% of science cases need observations at wavelengths >=2000 nm. Pursuing the full portfolio of science would also necessitate precise astrometry for planet mass measurement, rapid response capabilities, a large instantaneous field of regard, non-sidereal tracking, saturation mitigation strategies, and high dynamic range.
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All authors Courtney D. Dressing, Danica Adams, Evelyne Alecian, Gagandeep Anand, Giada Arney, Sarah Gomes Aroucha Barbosa, Martin Barstow, Joanna K. Barstow, Rachael L. Beaton, Eduardo Bendek, Svetlana Berdyugina, Julie Biedermann, Sarah Blunt, Sanchayeeta Borthakur, Kara Brugman, Joseph N. Burchett, Eric Burns, Jenna M. Cann, Ludmila Carone, Cody A. Carr, Richard Cartwright, Renyue Cen, Jean-yves Chaufray, Pin Chen, Lígia F Coelho, Kyle Cook, Nicolas B. Cowan, Patricio E. Cubillos, Alexandre David-Uraz, Tansu Daylan, Jessica E. Doppel, Leonardo dos Santos, Meredith Durbin, Rana Ezzeddine, Tara Fetherolf, Theresa Fisher, Leigh N. Fletcher, Luca Fossati, Ana I Gómez de Castro, Kaz Gary, Varoujan Gorjian, Yasuhiro Hasegawa, Qiuhan He, Natalie Hinkel, Keri Hoadley, Renyu Hu, Noam Izenberg, Estelle Janin, Mathilde Jauzac, Stephen R. Kane, Theodora Karalidi, Émilie Anne Lafléche, David J. Lagattuta, Érika Le Bourdais, Mary Anne Limbach, Jacob Lustig-Yaeger, Eric Mamajek, Kathleen Mandt, Frédéric Marin, Taro Matsuo, Stephan R. McCandliss, Michael W. McElwain, Emma Miles, Michiel Min, Leonidas A. Moustakas, Coralie Neiner, Elisabeth Newton, James W Nightingale, Stephanie Olson, Colby Ostberg, Apurva V. Oza, Fabio Pacucci, Roberta Paladini, Niki Parenteau, Lynnae C. Quick, Ramses Ramirez, Sukrit Ranjan, Isabel Rebollido, Bin B. Ren, Kurt D Retherford, Jason Rhodes, Ian U. Roederer, Sabina Sagynbayeva, Edward Schwieterman, Adam Smercina, Krista Lynne Smith, Antoine Strugarek, Megan Taylor Tillman, Vivian U, Georgios N. Vassilakis, Hannah R. Wakeford, Sara Walker, Siyi Xu, Lulu Zhang, Alejandra Aguirre-Santaella, Munazza K. Alam, Amirnezam Amiri, Ramya M Anche, Sarah E. Anderson, David R. Ardila, Karla Z. Arellano-Córdova, Natasha E. Batalha, Thomas G.Beatty, Juliette Becker, Enrica Bellocchi, Mark Booth, Médéric Boquien, Sarah E. I. Bosman, Jean-Claude Bouret, Vincent Bourrier, Matteo Brogi, Andrew M. Buchan, Blakesley Burkhart, Jennifer A. Burt, José A. Caballero, Sarah L Casewell, Frances H. Cashman, Laura Chin, Yumi Choi, Jessie Christiansen, Francesca Civano, Kyle W. Cook, Brandon Park Coy, Brendan P Crill, Leroy Cronin, Håkon Dahle, Mario Damiano, William Danchi, Satyapriya Das, Brice-Olivier Demory, Jamie Dietrich, Steven Dillmann, Chuanfei Dong, Dwaipayan Dubey, Patrick Dufour, Arika Egan, Christiana Erba, Steve Ertel, Raissa Estrela, Vincent Van Eylen, Virginie Faramaz-Gorka, Andrzej Fludra, Sophia Flury, Andrew Fox, Kevin France, David M. French, Marina Galand, Tianmu Gao, Antonio García Muñoz, Miriam Garcia, Kenneth Gayley, Megan Gialluca, Samantha Gilbert-Janizek, Leonardos Gkouvelis, Kenneth E. Goodis Gordon, Clémence Gourvès, Jonathan Grone, Jacob Haqq-Misra, Caleb K. Harada, Zachary Hartman, Samantha Hasler, Calum Hawcroft, Matthew J. Hayes, Amanda R. Hendrix, Brandon Hensley, Svea Hernandez, Erin K. S. Hicks, Benne W. Holwerda, Carly Howett, Ziyu Huang, Richard Ignace, Caitriona M Jackman, Chafi Jamal, Shingo Kameda, Tiffany Kataria, Gagandeep Kaur, Finnegan Keller, Habib Khosroshahi, Alina Kiessling, Kristina Kislyakova, Oleg Kochukhov, Anton M. Koekemoer, Brad Koplitz, Joshua Krissansen-Totton, Jiri Krticka, Alvaro Labiano, Pierre-Olivier Lagage, Steph LaMassa, Erini Lambrides, Alexandra Le Reste, Nan Liu, Joe Llama, Emma Louden, Nataliea Lowson, Isabel Márquez, Evelyn J. R. Macdonald, Meredith MacGregor, Sangeeta Malhotra, Richard Massey, Erin May, L. C. Mayorga, Michael McElwain, Sean McGee, Alexia McKenzie, Athina Meli, Bertrand Mennesson, Connor Metz, Drew M. Miles, Aquib Moin, Mark Moussa, Themiya Nanayakkara, Dibyendu Nandy, Yaël Nazé, Marc Neveu, Eric Nielsen, John Noonan, Jessica L. Noviello, John M. O'Meara, Antonija Oklopčić, Chris Packham, Enric Palle, Emaad Paracha, Lucas Patty, Vasiliki Pavlidou, Sarah Peacock, Chris Pearson, Marc Postman, Andreas Quirrenbach, Swara Ravindranath, Seth Redfield, Joe P. Renaud, Malena Rice, Jane R. Rigby, Giulia Roccetti, Keighley E. Rockcliffe, Donna Rodgers-Lee, Jael Rojas Miguel, Maissa Salama, Samir Salim, Evan Scannapieco, Claudia Scarlata, Martin Schlecker, Steve Schulze, Paul Scowen, Darryl Zachary Seligman, Zacory Shakespear, Evgenya Shkolnik, Nick Siegler, Breann Sitarski, Louie Slocombe, Gopika SM, Russell J. Smith, Jennifer Sobeck, Daphne Stam, Kendall Sullivan, Takahiro Sumi, Yudai Suzuki, Christy Till, Armen Tokadjian, Vasuda Trehan, Grant Tremblay, Noah Tuchow, Margaret Turcotte Seavey, Jake D. Turner, Sarah Tuttle, Asif ud-Doula, Anna Grace Ulses, Connor Vancil, Aline Vidotto, Geronimo Villanueva, Jessica M Weber, Dale Weigt, Maximilian von Wietersheim-Kramsta, Thomas G. Wilson, David J. Wilson, Nicholas F. Wogan, Maria Womack, Michael L. Wong, John F Wu, Mark Wyatt, John Ziemer, Tiziano Zingales, Ryan Begley, Enrico Biancalani, Dmitry Blinov, Alexandre Branco, Esra Bulbul, Guillaume Chaverot, Catherine A. Clark, Jaime S. Crouse, Filippo D'Ammando, Achrene Dyrek, Oscar A. Flores Gaitán, Searra Foote, Cecilia Garraffo, Christopher Garry, Nikolaos Georgakarakos, Arvind F. Gupta, Daniel Huber, Brianna Isola, Nikhita Kalluri, Aafaque Khan, Amir H. Khoram, Adam B. Langeveld, Lucie Leboulleux, Briley Lewis, Anna Lewkowicz, Laurent Mahy, Liton Majumdar, Luigi Mancini, Joice Mathew, Dimitri Mawet, David Mouillet, Shantanusinh Parmar, Junellie Perez, Lorenzo Pino, Alex Polanski, Francisco J. Pozuelos, Tyler Richey-Yowell, Cleber Silva, Ramdayal Singh, Arif Solmaz, Angelle Tanner, Konstantinos Tassis, Luca Tonietti, Laura D. Vega, Aiden S. Zelakiewicz

2608.11294 · 11 Aug · 215 pages, 18 figures, 16 tables. This to-be-submitted manuscript summarizes and synthesizes science cases developed by the Habitable Worlds Observatory START and science working groups. See Table 1 for a roadmap, Table 5 for a list of science cases, Figure 11 for a visualization of common observational needs, Figure 16 for connections to Astro2020, and Tables 6-15 (after conclusions) for details

Abstract PDF $PLNT ×2$EVO ×1$GLXY ×1

Instrumentation and Methods for Astrophysics

Full-Covariance Bayesian Inference of Stochastic Gravitational Wave Backgrounds with Time-Domain Simulations for Taiji-like Missions

Qingyuan Liang, Ju Chen, Minghui Du et al. (+1 more)

For Taiji-like missions, we implement a Bayesian spectral inference framework that combines second-generation time-domain (TD) simulations of time-delay interferometry (TDI) with a frequency-domain (FD) spectral likelihood for stochastic gravitational-wave background (SGWB) analyses. The \(X,Y,Z\) Michelson streams generated with \trianglesim{} are divided into finite segments, Fourier transformed, and modeled with a segment-dependent complex \(3\times3\) covariance matrix. For each segment we evaluate the orbit-dependent response functions and noise transfer functions, allowing unequal-arm and time-evolving effects to enter through the full \(XYZ\) covariance. Controlled simulations performed with \trianglesim{} show that the calculated functions reproduce the realization-averaged spectra at the few-percent level over the retained frequency band away from TDI nulls. We then compare parameter-estimation results for static equal-arm FD, equal-arm TD, and unequal-arm TD configurations, using in each case a full \(XYZ\)-covariance likelihood matched to the corresponding detector configuration. All three yield consistent uncertainty trends and Bayesian-evidence diagnostics for astrophysical-background recovery after marginalizing over instrumental noise and an effective Galactic double-white-dwarf foreground. Finally, in a ten-parameter model containing instrumental noise, an effective Galactic double-white-dwarf foreground, a stochastic astrophysical background, and a sound-wave spectrum from a cosmological first-order phase transition, we recover its peak amplitude and frequency and find Bayesian evidence favoring its inclusion in all three matched configurations.
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All authors Qingyuan Liang, Ju Chen, Minghui Du, Huai-Ke Guo

Instrumentation and Methods for Astrophysics

Eclipses by Artificial Satellites to Measure the Angular Sizes of Stars

Leo W.H. Fung, Albert Wai Kit Lau, Richard Massey et al. (+1 more)

Direct measurements of the angular sizes of stars (other than our Sun) are inherently limited by telescopes' optical diffraction limit. The spatial diffraction limit can be overcome by using time-domain information when stars are `eclipsed' by anything moving in the foreground: artificial satellites or the Moon (known as `lunar occultation imaging'). Here we analyse the angular resolution achievable by high-speed photon counting devices, when stars are eclipsed for several microseconds by one of the thousands of satellites now in low or mid-Earth orbit. We also build a full Bayesian statistical treatment for analysing simulated observations. We show that eclipses by the moon and satellites deliver $<2$ milliarcsecond resolution for $\sim$$10^4$ stars every year, with the diameters of $\sim$$10^1 - 10^2$ stars constrained to better than $0.5$ milliarcseconds. The application of satellites requires an ultra-fast, photon-resolving detector, capable of continuous readout with inter-frame delay controlled within $\lesssim 1$ $\mu$s. Such a fast rate can easily be handled by the SPINA instrument, which has demonstrated $8$ ns inter-frame delay, and potentially by the Cherenkov Telescope Array.
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All authors Leo W.H. Fung, Albert Wai Kit Lau, Richard Massey, George F. Smoot

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

All You Need is not $\Omega_\mathrm{gw}$: Beyond the Mean of the Cross-Correlation Estimator when Searching for an Astrophysical Gravitational-Wave Background

Haowen Zhong, Francesco Iacovelli, Vuk Mandic et al. (+1 more)

Searches for the stochastic gravitational-wave background (SGWB) using ground-based detectors rely heavily on the cross-correlation estimator $\bar C_f$, whose statistical properties determine the theoretical foundation for inference frameworks built on it. Past analyses usually assume Gaussianity of $\bar C_f$, but this assumption has not been systematically tested for a background of astrophysical origin like the one produced by compact binary coalescences. In this work, we decompose $\bar C_f$ into three physically motivated components: (1) the mean intensity, (2) the geometrical shot noise, and (3) the polarization leakage, and we compute 90% credible intervals for its cumulants up to fourth order for the binary black hole, binary neutron star, and neutron star-black hole populations by propagating local merger rate uncertainties. We find that for the upcoming LIGO O5 sensitivity, $\bar C_f$ remains effectively Gaussian for all three populations, validating current Gaussian likelihood frameworks. For Cosmic Explorer (CE), however, the $\bar C_f$ produced by binary black holes becomes non-Gaussian, with skewness and excess kurtosis of $0.31^{+0.04}_{-0.03}$ and $1.3^{+0.4}_{-0.3}$, respectively, in the most sensitive band over a one-year observation period. For binary neutron star and neutron star - black hole mergers, $\bar C_f$ remains largely Gaussian even at CE. These results indicate that the Edgeworth expansion provides an adequate leading-order description of the non-Gaussianity expected in the next-generation era, while also motivating the development of more sophisticated statistical methods for a more accurate treatment.
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All authors Haowen Zhong, Francesco Iacovelli, Vuk Mandic, Emanuele Berti

Instrumentation and Methods for Astrophysics

High-temperature photovoltaics for solar-electric Oberth maneuvers: ton-class payload feasibility for interstellar-precursor missions

Nadim Maraqten, Willem van Lynden, Carlos Gómez de Olea Ballester et al. (+1 more)

In-situ exploration beyond the giant planets remains rare because timely Solar System escape demands very high specific orbital energy, which existing concepts typically achieve only with small payloads, super-heavy launchers, or nuclear-powered propulsion. Motivated by laboratory demonstrations of high-intensity, high-temperature (HIHT) solar cells operating near $400\,^{\circ}\mathrm{C}$, we assess a solar-electric Oberth maneuver that concentrates thrust near a $0.3\,\mathrm{AU}$ perihelion. Evolutionary steering optimisation indicates that an expendable Falcon Heavy could deliver ton-class payloads to $200\,\mathrm{AU}$ within 25 years if HIHT power systems reach specific powers about $10\%$ above present-day conventional levels with a Jupiter gravity assist, or about twice those levels on a direct trajectory, under the stated assumptions. The gain stems from a threefold increase in specific orbital energy for the same $\Delta v$ compared with a $1\,\mathrm{AU}$ spiral. These results suggest HIHT photovoltaics could shift from survival hardware to propulsion-enabling technology for high-energy deep-space missions.
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All authors Nadim Maraqten, Willem van Lynden, Carlos Gómez de Olea Ballester, Andreas M. Hein

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

Spectroscopic Binary Detection as Agent-Callable Tools: Detecting 40,000+ Main-Sequence Binary Candidates from SDSS DR19 APOGEE Spectra

Serat M. Saad and Yuan-Sen Ting

Unresolved binaries are common in spectroscopic surveys, and their blended light biases the parameters inferred for them. Methods to detect them exist, but applying one to a new data release is limited mostly by operating know-how that is rarely written down. We package the double-lined spectroscopic binary decomposition of El-Badry et al. (2018b) for reuse on APOGEE spectra, with the executable operations as nine tool servers built on the Model Context Protocol (MCP) and the operating decisions as a Skill. Run over the 238,205 DR19 dwarfs under a fixed driver script, the classifier flags 41,466 SB2 candidates with median mass ratio q = 0.91, about fifteen times the 2,645 identified in DR13, though not at matched purity. The 8.1% control false-positive rate implies that close to 40% are single stars, so we release the sample as a candidate list. Refitting the individual visits confirms 68.5% of the multiply-visited SB2 and adds 519 single-lined velocity variables and 8,981 orbit-ready systems. We compare the eccentricities of the best-sampled binaries and find no significant difference between the close twins (q > 0.95) and matched non-twins, which excludes an eccentricity excess of the kind measured at wide separations. An ablation of two operating decisions illustrates that a fresh agent recovers a removed decision only when its absence leaves a measurable trace in the fit. We release the tools, the Skill, and the DR19 catalog with its multi-epoch supplement.
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Instrumentation and Methods for Astrophysics

Wavefront Profiling via correlation of GLAO open loop telemetry

Eden A. McEwen, Ryan Dungee, Mark Chun et al. (+3 more)

Adaptive Optics (AO) used in ground based observatories can be strengthened in both design and algorithms by a more detailed understanding of the atmosphere they seek to correct. Nowhere is this more true than on Maunakea, where a clearer profile of the atmosphere informs AO system development from the small separations of Extreme AO (ExAO) to the wide field Ground Layer AO (GLAO). Employing telemetry obtained from the 'imaka GLAO demonstrator on the University of Hawaii 2.2-meter telescope, we apply a wind profiling method that identifies turbulent layer velocities through spatial-temporal cross correlations of multiple wavefront sensors (WFSs). We compare the derived layer velocities with nearby wind anemometer data and meteorological model predictions of the upper wind speeds and discuss similarities and differences. The strengths and limitations of this profiling method are evaluated through successful recovery of injected, simulated layers into real telemetry. We detail the profilers' results, including the percentage of data with viable estimates, on four characteristic 'imaka observing runs on open loop telemetry throughout both winter and summer targets. We report on how similar layers are to external measures, the confidence of these results, and the potential for future use of this technique on other multi conjugate AO systems.
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All authors Eden A. McEwen, Ryan Dungee, Mark Chun, Jessica R. Lu, Olivier Lai, Christoph Baranec

Instrumentation and Methods for Astrophysics

Application of continuous corrections in widefield imaging obtained with the IDGCAL calibration method

Sebastiaan van der Tol

Image Domain Gridding (IDG) is an efficient method to evaluate A-projection, a method for correcting for direction dependent effects (DDEs) in radio astronomical imaging. The corrections i.e. the A-terms need to be estimated from the observed data through calibration. IDG-CAL is a calibration algorithm that employs the IDG algorithm in an iterative fashion to estimate A-terms directly. Initial results for low order A-terms are promising, however for deeper images higher order A-terms are needed. Here two improvements to IDG-CAL are proposed to 1) reduce the computational cost of A-terms described by more parameters and 2) optimize the set of basis functions describing the A-terms based on a stochastic model of the gain variations and the model image.
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