High Energy Astrophysical Phenomena
Gamma-ray Modes in a Transitional Pulsar
Maksat Satybaldiev and Manuel Linares
Transitional millisecond
pulsars (tMSPs) exhibit a unique sub-luminous disk state, at the cross-roads between
accretion and rotation power, where they switch between two distinct X-ray modes. We present the discovery of gamma-ray modes in PSR J1023+0038, the first confirmed tMSP, from stacking
Fermi-LAT data during the modes (which we identify using simultaneous X-ray observations). Surprisingly, we find that gamma-rays and X-rays are anti-correlated during this mode switching: the gamma-ray flux is higher in the X-ray low mode, and vice versa. This contradicts the state-of-the-art model, which predicts bright gamma-rays from the interaction between the
pulsar wind and surrounding disk via synchrotron and inverse Compton processes. Because the
pulsar wind is likely absent in the gamma-ray high (X-ray low) mode, which is also brighter in the
radio band, we suggest that jet emission is dominant in GeV gamma-rays.
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High Energy Astrophysical Phenomena · Cross-listed from gr-qc
Antikick Relation in High-Energy Head-On Collisions of Spinning Black Holes
Carlos O. Lousto, James Healy, Alessandro Ciarfella et al. (+1 more)
The collision of black holes at relativistic speeds probes
gravity in its most extreme dynamical regime. While the maximum gravitational
recoil from grazing high-energy collisions ($\approx28\,562$~km/s, i.e., $\sim0.1c$) and the maximum radiated energy $E_{\rm rad}$ and remnant
spin $\alpha_f^{\max}$ from such encounters ($E_{\rm rad}/M_{\rm ADM}\approx32\%$ where $M_{\rm ADM}$ is the ADM mass, and $\alpha_f^{\max}\approx0.987$) have been established previously~\cite{Healy:2022jbh,Healy:2024lhl}, here we focus on the head-on high-energy collision of equal-mass spinning black holes and on the detailed structure of the resulting
recoil. Performing a sequence of full numerical simulations for
spin magnitudes $s=0.5,0.65$, and $0.8$ over a range of initial momenta $\gamma v$, we characterize the peak
recoil $V_p$, the final
recoil $V_f$, and the antikick $\Delta V\equiv V_f-V_p$, and we provide phenomenological fits of their dependence on $\gamma v$ and $s$. We complement these results with a zero-frequency-limit (ZFL) analysis of the radiated energy and momentum, a quasinormal-mode model of the antikick, and a superposed boosted double-Kerr close-limit estimate. We find that in the relativistic regime ($\gamma v>1$) the peak and final
recoil are directly proportional, $V_p\approx7.4\,V_f$ (equivalently $\Delta V \approx-6.4\,V_f$), largely independent of both the initial momentum and the
spin magnitude, pointing to a common post-merger relaxation. While the ZFL predicts a leading linear-in-
spin dependence, the close-limit analysis predicts a leading $s^3$ dependence of the
recoil amplitude; with the three
spin magnitudes studied here the empirical exponent is $s^{1.27\pm0.08}$, motivating an even higher energy collision
spin sequence study.
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All authors Carlos O. Lousto, James Healy, Alessandro Ciarfella, Hiroyuki Nakano
Cosmology and Nongalactic Astrophysics
Model-Independent Indication for a Localized Anomaly in the Late-Time Expansion History
Shibendu Gupta Choudhury, Purba Mukherjee, Eleonora Di Valentino et al. (+1 more)
We investigate the late-time expansion history of the Universe using a model-independent spline reconstruction of cosmological distances based on the latest DESI DR2
baryon acoustic oscillation (BAO) measurements and the DES Dovekie Type Ia
supernova compilation. Comparing the reconstructed expansion history with the prediction of the Planck 2018 $\Lambda$CDM model, we identify a localized deviation over the
redshift interval $0.3\lesssim z\lesssim0.6$, reaching a maximum significance of approximately $3.5\sigma$ at $z\simeq0.47$. We demonstrate that this feature persists under substantial variations of the reconstruction methodology,
dataset composition and sound-horizon calibration. Mock analyses further show that the reconstruction is unbiased and that the observed anomaly is unlikely to arise from reconstruction bias or miscalibrated uncertainties. If confirmed by future observations, this localized feature could point to previously unrecognized late-time physics or reveal subtle inconsistencies between early and late Universe cosmological probes.
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All authors Shibendu Gupta Choudhury, Purba Mukherjee, Eleonora Di Valentino, Anjan A Sen
Astrophysics of Galaxies
Alignment of the Milky Way and M31 with their cosmic environment. New insights from constrained Local Group simulations
Hanneke C. Woudenberg, Amina Helmi, Ewoud Wempe et al. (+4 more)
The large-scale environment is thought to play an important role in setting
galaxy properties. The Milky Way (MW) and Andromeda (M31) reside in the Local Group, embedded in the Local Sheet (LS). To study the sheet's influence on the dark matter (DM)
halo shapes,
spins, and disks orientations of MW and M31 analogues, we use a new suite of constrained Local Group simulations that reproduce the observed configuration of the two main
halos and the LS. We determine their shapes and
alignments relative to the LS analogues, and the effect of infall and coalescence of massive mergers. We find that the DM
halo shapes of our MW and M31 analogues are on average slightly rounder than literature reports for similar-mass
galaxies in random environments. We find preferential
alignment between the sheet normal and the
halos' minor axes, but not with the
halos'
spins. The present-day disk angular momenta ($L_{\rm disk}$) closely align with the
halos' minor axes (median $15^{+15}_{-8}$ degrees at $R_{\rm vir}$) and with the
halos'
spins. The direction of $L_{\rm disk}$ is often set by one of the two highest mass ratio mergers during the last 8-10 Gyr. While recent ($\leq 2$ Gyr) massive mergers can reorient the outer
halo's minor axis leading to twisted shapes, $L_{\rm disk}$ retains the imprint of the earlier
accretion event. These results can explain the peculiar
alignment of the MW's disk and DM
halo shape and their orientation relative to the LS. The prolate-like morphology and orientation of the MW's outer
halo can be explained by the Magellanic Clouds (and perhaps Sagittarius) accreting from within the LS. As their orbital planes are nearly perpendicular to the
Galactic disk, the disk orientation must be set earlier, possibly by the GES merger. This merger's estimated infall direction, highly inclined relative to the present-day LS, is broadly consistent with the LS's direction of maximum collapse.
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All authors Hanneke C. Woudenberg, Amina Helmi, Ewoud Wempe, Anna Genina, Simon D.M. White, Jens Jasche, Guilhem Lavaux
Instrumentation and Methods for Astrophysics
picoMUX: microcontroller based time-domain multiplexing readout for kilopixel TES arrays
Simon Tartakovsky, Alexandre E. Adler, Jason E. Austermann et al. (+23 more)
Advances in cryogenic SQUID-based time-domain multiplexing (TDM) have outpaced their warm readout electronics. Next generation CMB
telescopes are baselining kilopixel TES arrays with few viable electronic options. We present picoMUX, a new TDM readout electronics architecture that replaces the FPGA typically used in such systems with a complement of modern microcontrollers. Designed around the current generation NIST multiplexer, it fully exploits its differential nature and two-level switching. The system achieves the desired timing metrics (sub {\mu}s row dwell time) while reducing cost, complexity, and power consumption over a comparable FPGA solution. Preliminary noise measurements are consistent with expectations and show no evidence that the novel architecture introduces excess noise. picoMUX demonstrates how recent advances in microcontrollers enable simpler, low-power, low-cost TDM readouts for kilopixel TES arrays.
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All authors Simon Tartakovsky, Alexandre E. Adler, Jason E. Austermann, Steven J. Benton, Shannon M. Duff, Malcolm Durkin, Jeffrey P. Filippini, Aurelien A. Fraisse, Thomas J.L.J. Gascard, Sho M. Gibbs, Suren Gourapura, Jon E. Gudmundsson, Johannes Hubmayr, William C. Jones, Ashesh Khatua, Jared L. May, Darby McCauley, Johanna M. Nagy, Ivan L. Padilla, Ricardo R. Rodriguez, John E. Ruhl, M. Shaaf Sarwar, Christopher Rooney, Joseph van der List, Michael R. Vissers, Philippe Voyer
Cosmology and Nongalactic Astrophysics
Models with Non-minimal Coupling in Primordial Universe and Cosmological Observations
Alireza Talebian, Hassan Firouzjahi and Fereshteh Felegary
A non-minimal coupling between
gravity and the inflaton field is a generic contribution in inflationary cosmology. In this work, we consider models of inflation with a non-minimal coupling $-\xi\phi^2 R$ and study their observational predictions for the tensor-to-scalar ratio $r$ and the spectral index $n_s$. Unlike the conventional approach of working in the Einstein frame, we perform the analysis in the Jordan frame where the underlying dynamics, particularly the competition between the potential force and the coupling-induced friction, are more transparent. For suitable values of $\xi$, the system exhibits an extended constant-roll regime, in which this friction counteracts the potential force. Focusing on monomial potentials $V(\phi) \propto \phi^n$, we find that negative $\xi$ systematically reduces $r$ in the $(n_s, r)$ plane, while the shift in $n_s$ depends on the power $n$: for $n \geq 4$, the spectral index increases with $|\xi|$, whereas for $n < 4$, it decreases. Notably, the quartic model $V(\phi) = \lambda \phi^4/4$ with $\xi \lesssim -0.1$ shows good agreement with the ACT DR6 data and exhibits a distinct $n_s(\xi)$ dependence compared to other monomial cases. Our results demonstrate that non-minimally coupled models can effectively reconcile Planck and ACT observations, providing a unified framework for interpreting current CMB constraints.
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Earth and Planetary Astrophysics
When Stabilizing Feedbacks Wreak Havoc in Habitable Planets: Chaos at the Freezing Point in a Four-Feedback Climate Model
Chaucer Langbert, Dániel Apai and Renu Malhotra
The long-term habitability of Earth-like
planets is governed by the balance of positive and negative
climate feedbacks that regulate surface temperature and atmospheric composition. While some feedbacks, such as ice-albedo and silicate weathering, are thought to operate on many terrestrial
planets, the number and strength of additional
climate feedbacks may vary substantially from world to world. An important open question is whether and how the introduction of an additional
climate feedback influences long-term
climate evolution and complexity. To investigate this question, we extended a low-order
climate model including outgoing longwave radiation, ice–albedo, and carbonate–silicate weathering, with an additional generalized feedback. Across 35,864 simulations, we characterized dynamical behavior using the largest Lyapunov exponent (LLE). While 10.4% of explored parameter combinations exhibited positive LLEs, indicating chaos, the fraction rose to 25.6% within the stabilizing, near-freezing regime. This suggests that chaotic behavior is preferentially concentrated where a strong stabilizing feedback operates in the same temperature regime as a strong destabilizing feedback, contrary to the expectation that additional negative feedbacks should increase
climate stability. Increasing normalized volcanic outgassing shifts the chaotic regime toward lower
stellar flux and partially suppresses chaos at high instellation.
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High Energy Astrophysical Phenomena
A new model for the continuum spectra of AM CVn binaries and multi-messenger inference with normalizing flows
Nathan Steinle, Samar Safi-Harb, Austin MacMaster et al. (+5 more)
Future electromagnetic
telescopes, such as $\textit{NewAthena}$, $\textit{CASTOR}$, and an $\textit{AXIS}$-like mission, along with milli-Hz gravitational-wave (GW) detectors such as $\textit{LISA}$, are expected to unearth the population of
Galactic ultra-compact binaries (UCBs). Joint multi-messenger detections will probe the uncertain formation,
evolution, and observables of mass-transferring UCBs such as AM CVns, but theoretical tools need to be advanced to anticipate future data challenges. Motivated by this, we present a new forward model for the continuum emission of AM CVn binaries that connects source binary parameters to X-ray, optical, and ultraviolet observables. The model assumes GW-driven mass transfer with physically motivated prescriptions for
accretion energetics, emission geometry, absorption, and instrumental response. Combining this with $\textit{LISA}$ observations and the output of binary population synthesis enables exploration of the multi-messenger properties of AM CVns. Although uncertain, our model predicts that approximately one per $7000$ AM CVn binaries will permit a joint multi-messenger detection with $\textit{LISA}$, $\textit{CASTOR}$, and $\textit{AXIS}$. We also develop a framework for inferring binary parameters from the inverse model with a convolutional neural net and normalizing flows. Testing the trained flow with our synthetic AM CVn population, we find mean absolute fractional error on the inferred accretor mass of $0.05$, donor mass of $0.26$, orbital period of $0.1$, and distance of $0.2$, while Spearman's rank shows strongly correlated true and predicted distributions except for the donor mass. These efforts lay a foundation for follow-up studies that will explore detailed binary astrophysics and observational requirements for effective multi-messenger scientific discovery in the coming decade.
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All authors Nathan Steinle, Samar Safi-Harb, Austin MacMaster, Liliana Rivera Sandoval, Katelyn Breivik, Tyrone E. Woods, Tom Maccarone, Tom Wagg
High Energy Astrophysical Phenomena
High-Resolution Numerical Calculations of GRB Afterglow Plateaus arising from Stratified Ejecta
Paul C. Duffell and Ranadeep Ghosh Dastidar
Since the discovery of plateaus in GRB afterglows by Swift, they have been modeled predominantly by late-time energy injection. However, many studies have suggested that the plateau may be modeled by an early phase before reverse shock crossing (either coasting with constant Lorentz factor or decelerating very slowly as the reverse shock crosses the ejecta). The slope of the early plateau provides some constraints the stratification of the fastest-moving ejecta, which could be the ejecta responsible for the
prompt emission. However, numerical studies typically do not model the jet as a stratified
outflow; the reason being the extremely high resolution required in order to accurately evolve this tiny amount of highly relativistic material. In this study, we perform high-resolution numerical calculations ($\Delta r/r \lesssim 10^{-5}$) verifying that a stratified ejecta structure can indeed produce an afterglow plateau in both wind ($k=2$) and ISM ($k=0$) environments, and computing break times explicitly. We evolve the relativistic hydrodynamics using the JET code, and post-process this to compute the afterglow using the Firefly code. Our results show that a stratified ejecta structure (which should generically be present in GRB jets) is sufficient to explain GRB afterglows, and the plateau slopes can be used to constrain the ejecta stratification. We additionally provide precise measured scalings for the plateau duration as a function of the characteristic Lorentz factor of the ejecta. The long duration of typical plateaus requires a very modest characteristic Lorentz factor for the ejecta ($\gamma_0 \sim 10-50$), in agreement with other afterglow plateau models.
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Astrophysics of Galaxies
Dynamical modelling of giant radio quasars in the HETDEX Spring Field
T. M. O. Franzen, J. Machalski, M. Jamrozy et al. (+4 more)
Giant radio sources are defined as extragalactic
radio sources, hosted by
galaxies or
quasars, with linear sizes $\geq 0.7$ Mpc. They are thought to represent the final stage of the
evolution of
radio galaxies whose sizes range from pc to Mpc scales. We analyse in detail the
radio morphology and spectra between 54 MHz and 4.85/15.5 GHz of 15
giant radio quasars (GRQs) in the HETDEX Spring Field, and fit dynamical
evolution models to the sources' observational properties to study their physical parameters (age of the lobes, jet power, ambient medium density etc.). We compare the physical parameters of the GRQs with published results for a compiled sample of Fanaroff-Riley type II
radio sources. We find that the GRQs evolve in significantly lower medium densities, both at the central core radius and in front of the lobes, than smaller-sized
radio quasars (RQs) with similar jet powers. The derived central core densities for both populations are, however, highly sensitive to the assumed ambient medium density profile. For both populations combined, the jet power, $Q_{\text{j}}$, is anti-correlated with the age of the lobes, $t_l$ ($R = -0.67$, where $R$ is the Pearson correlation coefficient), as well as the linear size, $D_l$ ($R=-0.32$), but $t_l$ is a much stronger indicator of $Q_{\text{j}}$ than $D_l$. Using a Spearman partial rank correlation analysis, we demonstrate that there is a fundamental relation between $Q_{\text{j}}$, $t_l$, and $D_l$, despite the strong underlying correlation between age and size.
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All authors T. M. O. Franzen, J. Machalski, M. Jamrozy, R. Morganti, D. A. Green, Y. C. Perrott, T. W. Shimwell
Instrumentation and Methods for Astrophysics
Fast and accurate bandpass integration of complex SEDs with neural networks
L. A. Bianchi
The paper presents a novel ML-based approach for fast and accurate bandpass integration of spectral energy distributions (SEDs). The non-locality of the integral operator involved guarantees the smoothness of the target function to be approximated, making it an excellent use-case for neural networks. The computational method developed for this work has been wrapped within pyfine (FINE: Fast Function Interpolation via NEural NEtworks). This new Python package makes the relevant code available and easy to use by everyone within the scientific community. The method is demonstrated with two different bandpass integration test cases with 3 and 9 free parameters, respectively, where both accuracy and computational performance are analyzed. The results show that the method is capable of predicting values of the bandpass integral with maximum relative residuals as low as 0.002% and 0.08% respectively, within the sampled region of the parameter space, fast run times, and very little
memory overhead. The usage of pyfine is especially effective when the computation of an SED functional form, given a set of values for its free parameters, is expensive. However, already in the first of the two test cases, where a simple modified black body SED was employed, the neural network's measured run times resulted faster by two orders of magnitudes than an optimized multithreaded version of the “brute force” exact calculation of the integral.
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Astrophysics of Galaxies
SMA Observations of the Archetypal Compact Steep-spectrum Radio Source 3C 303.1
Rushikesh Bhutkar, Mark Gurwell, Christopher O'Dea et al. (+5 more)
AGN (active
galactic nuclei) feedback plays a crucial role in shaping
galaxy evolution. Numerical simulations show that the kinetic energy transfer efficiency from
radio jets to interstellar medium (ISM) is relatively high, suggesting a significant role of
radio jets in the feedback. We investigate AGN feedback on cold gas in the compact steep-spectrum (CSS)
radio source 3C 303.1. CSS sources are largely young
radio galaxies evolving through dense environments of their host
galaxies. This early evolutionary phase likely represents a critical stage in which the
radio source has maximum impact on host
galaxy evolution. 3C 303.1 is the only CSS source so far showing
alignment in optical, X-ray and UV with the
radio structure, making it an interesting source to investigate jet-feedback. We present continuum and spectral line observations of the J=3-2 transition of carbon monoxide ($^{12}$CO) of 3C 303.1, obtained with the Submillimeter Array. We detect continuum emission at 221.1 and 271.2 GHz. We do not detect the $^{12}$CO(J=3-2) line and derive an upper limit on the molecular gas mass of $\sim 2.3 \times 10^{9}\ \mathrm{M_\odot}$. The gas to-
dust mass (G/D) ratio is found to be at the lower end of typical
Galactic values, and the
star-formation rate (SFR) derived is moderate but declining likely due to a recent quenching event. Therefore, $^{12}$CO(J=3-2) non-detection, relatively low G/D ratio, and the moderate but declining SFR point to the shock-heating and/or removal of CO gas by AGN, consistent with the AGN feedback signatures observed in 3C 303.1.
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All authors Rushikesh Bhutkar, Mark Gurwell, Christopher O'Dea, Mojegan Azadi, Belinda Wilkes, Stefi Baum, D. J. Saikia, Grant Tremblay
Solar and Stellar Astrophysics
Structure and Dynamics of the Inner Corona Measured from the DEB Initiative 2024 Eclipse Image Sequence
Matthew J Penn, Robert Baer, Chris Mandrell et al. (+66 more)
The Dynamic Eclipse Broadcast (DEB) Initiative citizen science program observed coronal visible continuum brightness during the 2024 April 8 total eclipse from locations across North America. We present results from 11 DEB sites spanning 2700 km of distance and showing 49 minutes of
evolution. The coronal brightness radial profiles from these
telescopes are tightly correlated from 1.2 to 4.0
solar radii and comparable to published photometric coronal intensities. The coronal flattening parameter is measured from 1.4 to 2.8
solar radii. A Ludendorff index of 0.0761 +/- 0.0007 is computed but the extrapolation techniques used by some to calculate this index are shown to disagree with this direct measurement, and alternate structure parameters are suggested. Measured radial velocities are compared with an MHD model of the corona during the eclipse from Y. Li et al. (2026). A polar downflow is measured with an average radial velocity of -37 +/- 3 km s-1 and a deceleration of 14 +/- 3 m s-2 at a speed and position which agrees with the model. The predicted mixture of
outflows and downflows at low heights is seen, as well as
outflows in two western regions of the corona. The fastest observed
outflow has a radial speed of 105 km s-1 and is likely associated with a transient event not predicted by the model. Future DEB Initiative eclipse experiments can more tightly constrain models of the inner corona by using both coronal intensity and radial velocity measurements.
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All authors Matthew J Penn, Robert Baer, Chris Mandrell, Corinne Brevik, Castor Fu, Mike Conley, Richard Danley, Harvey Henson, David Iadevaia, Jonathan Mangin, Chris Midden, Brodye Miller, Claude Plymate, Teresa Plymate, Zack Stockbridge, Kevin Rasso, Autumn Awalt, Avery Awalt, Gracie Awalt, Josh Awalt, Lauree Rasso, Mike Chartrand, Noah Lambert, Zoee Rasso, Kevin Cobble, Amelia Menezes, Andrew Yu, Felix Mei, Hanson Du, Ramesh Pattar, Vishrut Kumaran, Robert Auburger, Brian J. Drake, Seth Antozzi, Chloe Rectanus, Grayson Garner, Michael Weiss, Bill Kloepping, Deborah Grubis, Maryanne Angliongto, Ashvik Chilakala, Carl Buz McCullough, Mark Bremer, Christina Adair, Amber Huffman, Charon Adair, Gabbie Graham, Nick Tillerson, Fred Isberner, Candy Isberner, Harry Treece, Lisa Sikorski, Sage Julian-Fralish, Heidi Schran, Addison Greene, Bibodh Baral, Crow Ely, Nolan Hodgson, Olive Blackmar Rice, Olivia Andrews, Olivia Freeman, Quinn Donnelly, Serenity Prince Kirk, Carmen Tran, Brianna Blanchard, Kyan West, Landon Bevier, Murali Saravanan, Jeremy Wright
Astrophysics of Galaxies
The MAGPI survey: Stellar population radial trends and mass assembly in star-forming galaxies at z~0.3
Federica Mauro, Bodo Ziegler, Iris Breda et al. (+19 more)
The
evolution of
galaxies from
cosmic noon to the present day provides a key window to probe the balance between early, rapid bulge formation and prolonged disk growth. The epoch at $z \sim 0.3$ marks a crucial transitional phase between the peak of
cosmic star formation and the predominantly quiescent local Universe. In this work, we examine the spatially resolved
stellar populations of 34
galaxies at $z \sim 0.3$ to quantify radial gradients in age,
stellar metallicity, and
star formation activity, and disentangle the distinct evolutionary pathways of inner and outer
galactic components. We utilise MUSE integral-field spectroscopy data cubes from the MAGPI survey at
redshifts of $0.28 < z < 0.35$.
Stellar population properties are derived using the spectral synthesis codes FADO and Starlight, and radial profiles are constructed by fitting isophotal annuli to the
galaxy continuum emission. We further reconstruct
star formation histories and cumulative mass assembly curves for inner and outer regions. We find pronounced negative radial gradients in age and negative to flat gradients in
stellar metallicity. Inner regions are systematically older and more metal-rich than their surrounding outskirts, with age differences up to 3-4 Gyr in the most massive systems. H$\alpha$ equivalent width profiles reveal centrally suppressed specific
star formation in most
galaxies.
Star formation histories and mass assembly curves demonstrate that
galaxy cores formed $80\%$ of their
stellar mass rapidly, within the first 2-3 Gyr of
cosmic time; while areas outside $\mathrm{1\,R_{eff}}$ assembled more gradually and sustained
star formation to later epochs. Outskirts evolve primarily through extended, secular
star formation, establishing the centrally concentrated quenching and inside-out growth that link high-
redshift systems to the quiescent
galaxies of the local Universe.
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All authors Federica Mauro, Bodo Ziegler, Iris Breda, Polychronis Papaderos, Gauri Sharma, Sabine Thater, Katherine E. Harborne, Trevor Mendel, Emily Wisnioski, Claudia Lagos, Caroline Foster, Andrew J. Battisti, Ryan S. Bagge, Joss Bland-Hawthorn, Scott Croom, Siddhartha Gurung-López, Marcie Mun, Tamal Mukherjee, Sarah M. Sweet, Lucas M. Valenzuela, Glenn van de Ven, Tayyaba Zafar
Instrumentation and Methods for Astrophysics
Updates to the WFC3/IR Photometric Stability Stellar Cluster Study
Ky Huynh and Varun Bajaj
The WFC3/IR channel has been shown to lose sensitivity over time. The sensitivity loss rate has been quantified in past works and we extend those measurements into 2026 using photometry of uncrowded regions of
star clusters 47 Tucanae and Messier 4 in the F110W and F160W filters. This study adds 4-7 additional visits since Bajaj et al. (2022) for each target/filter combination. Using F160W data of 47Tuc, we find that the IR channel continues to lose sensitivity at a rate of -0.07% $\pm$ 0.01% per year using the full
dataset, and -0.06% $\pm$ 0.02% per year using only the first exposure of every visit. Using M4 data observed in F110W, we find a sensitivity loss rate of -0.13% $\pm$ 0.02% per year using the full
dataset, and -0.07% $\pm$ 0.03% per year using just the first exposure of every visit. We find that the rate of sensitivity loss has decreased since the previous study. This likely stems from the inclusion of more recent visits that were designed to mitigate persistence effects. These results suggest that earlier observations, which were not intended for sensitivity measurements, may have overestimated the IR channel's sensitivity due to the effects of persistence from bright sources. The IMPHTTAB reference file that contains the correction to the time-dependent sensitivity remains unchanged from the sensitivity measurements of this report.
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High Energy Astrophysical Phenomena
Investigating the Periodic X-ray Behaviour in the Eclipsing AGN NGC 6814
T. O. Hodd, L. C. Gallo, A. G. Gonzalez et al. (+2 more)
A 2016 XMM-Newton X-ray light curve of the Seyfert 1.5
galaxy NGC 6814 exhibited clear eclipsing behaviour, with distinct ingress and egress, during half of the observation. Here, we report on the periodic behaviour in the light curve prior to the eclipse. We use timing and spectral analysis techniques to quantify the behaviour and examine the characteristics of the periodic signal. A superlet transform of the X-ray light curve reveals a period of ~45-50 $\mu$Hz in the initial 60 ks of the observation with a detection significance at the >90% level in both the broad (0.3-10 keV) and soft (0.3-1.0 keV) bands. The period is confirmed by fitting a sinusoid, and is also evident in the highest energy bands with diminished significance because of reduced signal-to-noise. There appear to be distinct changes in the variability behaviour during the eclipse as the measured period is modulated (stretched) at all energies. From phase-resolved spectra, we investigate possible physical causes of this periodic behaviour and find that it can be interpreted as changes in the covering fraction or a non-standard inner
accretion flow (e.g. truncated disc and misaligned flow). The non-standard inner flow appears consistent with previous reports of a truncated inner disc and compact corona in NGC 6814.
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All authors T. O. Hodd, L. C. Gallo, A. G. Gonzalez, J. M. Miller, D. Rogantini
Instrumentation and Methods for Astrophysics
Establishing baseline model performances for optical turbulence forecasting
M. De Sepibus, E. Masciadri, C. Weinberger et al. (+2 more)
Accurate optical
turbulence (OT) forecasts help
telescopes observe with maximum efficiency, as the performance of adaptive optics (AO) systems strongly depends on
turbulence conditions. OT
forecasting remains a challenging problem. A wide range of methods has been explored to address this problem, including numerical weather prediction (NWP) models, machine learning
algorithms, and hybrid approaches, each varying in complexity, computational cost, and accuracy. Assessing the performance of
forecasting methods is essential to
benchmark them against simple, well-defined reference models, known as baselines, which establish reference thresholds. This paper aims to calculate these thresholds for the astroclimatic and atmospheric parameters most relevant for ground-based astronomy related to two of these baseline methods that are suitable for use in two different types of forecast, which are among the most relevant for application to the ground-based astronomy: the forecast of the average of a parameter on a defined timescale and the forecast of the temporal
evolution of a parameter on a defined timescale. We apply these baseline methods to a
dataset related to a rich statistical sample of many years encompassing key astroclimatic and atmospheric parameters above the sites of the Very Large
Telescope and the Large Binocular
Telescope, and we discuss the implications of these results and the possibility of extrapolating such values for general rules. We demonstrate that the predictive performance of each reference method depends on the observing sites, the parameter that is forecasted, the forecast timescale, and the type of forecast used. That means that it is meaningless to quantify the performance of OT forecasts in absolute terms, since they depend on the context.
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All authors M. De Sepibus, E. Masciadri, C. Weinberger, C. Veillet, S. Ragland
Instrumentation and Methods for Astrophysics
Astra: an open-source fully autonomous robotic observatory control software
Peter P. Pedersen, David Degen, Lionel Garcia et al. (+12 more)
Robotic and autonomous observatories are critical for modern time-domain and high-cadence astronomical surveys. The operation of these facilities requires complex software coordination to manage hardware, schedule observations, and ensure safety. However, existing observatory control software are often proprietary and platform-locked or require complex message-brokering infrastructure. Here we present Astra (Automated Survey observaTory Robotised with Alpaca): an open-source, cross-platform Python system for the sustained, fully autonomous operation of astronomical observatories, requiring no external message-broker infrastructure. Astra controls observatory hardware via the ASCOM Alpaca protocol, and executes prescheduled observatory actions under continuous safety supervision. Its multi-device actions include plate-solve-based pointing correction with a local
Gaia–2MASS catalogue fallback, PID-controlled autoguiding, and autofocus. A FastAPI web service provides a browser UI, REST and WebSocket APIs for real-time status, image previews, and SQLite-backed telemetry and logs. Astra has run in fully unattended production since January 2024, scaling to six
telescopes across three facilities: the SPECULOOS-South network (4 $\times$ 1\,m class, Chile), SAINT-EX (1\,m class, Mexico), and the ETH Observatory (0.5\,m class, Switzerland), with no schedule aborts attributable to Astra software. Across the SPECULOOS-South network, it achieves sub-arcsecond autoguiding (0.11\unit{\arcsecond} median pointing scatter) and plate-solve failure rates below 1% on three of the four
telescopes (3% on the narrowest-field unit), demonstrating that an open, standards-based software stack can meet the reliability demands of production survey astronomy.
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All authors Peter P. Pedersen, David Degen, Lionel Garcia, Urs Schroffenegger, Daniel Sebastian, Sebastián Zúñiga-Fernández, Brice-Olivier Demory, Elsa Ducrot, Michaël Gillon, Matthew J. Hooton, Clàudia Janó-Muñoz, James McCormac, Mathilde Timmermans, Amaury H.M.J. Triaud, Didier Queloz
High Energy Astrophysical Phenomena
Momentum Space Resolution Dependence in Boltzmann Neutrino Radiation Hydrodynamics Simulations of Core-collapse Supernovae
Ryuichiro Akaho
Finite momentum space resolution is a primary source of uncertainty in solving the Boltzmann equation with the discrete-ordinates method. In this paper, the momentum space resolution dependence of Boltzmann
neutrino transport is studied by performing a series of two-dimensional core-collapse
supernova (CCSN) simulations. The effects on the explosion dynamics are discussed by individually varying the resolutions of the zenith and azimuth angles in momentum space, and of the energy. It is found that a coarse zenith angle resolution artificially facilitates the explosion, even turning non-exploding models into exploding ones. This is because the coarse zenith angle grid cannot capture the forward-peaked distribution, thereby underestimating the flux factor and making
neutrinos stay in the gain region for a longer time. The dependence on the azimuth angle resolution is found to have little effect for the present non-rotating models, which is understandable given the sphericity of the CCSN core. In contrast to the zenith angle resolution, a coarse energy resolution is found to artificially suppress the explosion. This is because the
neutrino heating rate at intermediate energies ($\sim30$–$50\,\mathrm{MeV}$) is underestimated in the low-resolution case. Finally, the resolution dependence is studied for a one-dimensional black hole (BH) forming model. Unlike the explosion dynamics, BH formation does not exhibit a strong angular dependence. On the other hand, a coarse energy resolution is found to delay the BH formation time. This is because the momentum feedback is overestimated at low resolution, which allows a more massive
neutron star to be supported.
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Cosmology and Nongalactic Astrophysics
Overview: Cosmology with the SKAO
Marta Spinelli, Ian Harrison, Richard A. Battye et al. (+5 more)
The SKA
telescopes will revolutionise our ability to do cosmology at
radio wavelengths, via both their own data and in synergy with other wavelengths. SKAO will be the first instrument able to conduct large-scale cosmological surveys as done in the last decades in the optical and near-infrared. This complementarity will be vital as cosmology hits the limit of systematic uncertainties.
Radio cosmology surveys will have radically different systematics, allowing data combinations across surveys to calibrate systematics and increase overall constraining power. Neutral hydrogen (HI) intensity mapping surveys are now reaching maturity, as demonstrated by the progress made by the MeerKLASS survey with MeerKAT. Along with continuum
galaxy surveys, they will provide detailed maps of the Universe covering large fractions of the sky, allowing us to answer questions about fundamental physics which can only be measured on the largest scales. In combination with weak
lensing and HI
galaxy probes, HI intensity maps will also measure the distributions of matter and velocities to give precisions tests of the $\Lambda$CDM model, including its foundational assumptions of isotropy and homogeneity. In combination with gravitational wave observations and fast
radio bursts, they will also help us measure the expansion history and
baryon content of the Universe. Here we provide an overview of the achievements of precursor surveys and the progress towards SKA cosmology, starting with AA* and reaching full maturity with AA4
telescopes.
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All authors Marta Spinelli, Ian Harrison, Richard A. Battye, Stefano Camera, Xuelei Chen, Roy Maartens, Mario G. Santos, Laura Wolz
Solar and Stellar Astrophysics
Searching for Stellar Activity Cycles using Flares II: The TESS CVZ
Tobin M. Wainer, Holland M. Stuart, Guadalupe Tovar Mendoza et al. (+3 more)
Magnetic activity cycles provide a fundamental constraint on
stellar dynamos, but remain difficult to identify beyond the Sun. However, recent studies have shown that
flares offer a unique tracer of activity cycle behavior. In this study, we use seven years of short-cadence observations from the Transiting
Exoplanet Survey Satellite (TESS) for over 14,000
stars in the Continuous Viewing Zone to search for long-term changes in
flare activity. For each
star, we perform injection and recovery tests and provide well-characterized completeness limits for
flare detection thresholds, and
flare finding results. From this search, we identify 17
stars with evidence of long-term variability in
flare rate, synonymous with activity cycle behavior. These candidates span a range of effective temperatures, rotation periods, and
flare-variability morphologies. One G-type
star, TIC 167344043, stands out as the clearest
solar-like case, despite rapid rotation and superflare activity. Our results identify candidate activity cycles in
stars that are more rapidly rotating and
flare-active than the typical
stellar-activity-cycle targets in the literature. These systems probe a new regime where
stellar dynamos are still evolving, providing critical constraints on when cycle-like
magnetic variability first emerges.
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All authors Tobin M. Wainer, Holland M. Stuart, Guadalupe Tovar Mendoza, Andrew R. Casey, Tom Wagg, James R. A. Davenport
Instrumentation and Methods for Astrophysics
The MICADO first light imager for the ELT: the SCAO module AIT in France, from the beta flat configuration towards the flat and final configurations
Yann Clénet, Vincent Lapeyrère, Eric Gendron et al. (+45 more)
MICADO is the designated ELT first light instrument, a near-infrared imager working at the diffraction limit of the
telescope thanks to a SCAO and an MCAO mode. Since summer 2024, MICADO is in its AIT phase and all MICADO partners are currently integrating their subsystems. The MICADO SCAO module will follow three successive AIT phases in France: the beta flat configuration, the flat configuration and the final configuration. In this contribution I will first present the progress made in the AIT of the beta flat configuration and its closed loop results. I will then present the performed and on-going tasks for the flat and final configurations (manufacturing, delivery and integration of several SCAO subsystems and pieces of software) and the results obtained so far in the flat configuration. I will then conclude with the expected following steps of the SCAO module AIT in Garching.
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All authors Yann Clénet, Vincent Lapeyrère, Eric Gendron, Fabrice Vidal, Frédéric Chapron, Mathieu Cohen, Sylvain Guieu, Roderick Dembet, Eric Meyer, Arnaud Sevin, Fanny Chemla, Olivier Dupuis, Kévin Cloiseau, Gilles Fasola, Karim Hussein, Sylvain Isambert, Julien Gaudemard, Florian Ferreira, Hervé Locatelli, Nicolas Gautherot, Antonin Poyard, Lahoucine Ghouchou, Emmanuel Tisserand, Alexandre Blin, Labasse Berthe, Srilakshmi Ramalingam, Claude Collin, Julian Porras, Nicolas Levraud, Caroline Kulcsár, Henri-François Raynaud, Benoit Sassolas, Laurent Pinard, Christophe Michel, Cyrille Blanchard, Ihsan Ibn Taïeb, William Wang, Samir Maria, Tristan Buey, Vincent Chevalier, Sylvestre Taburet, Dalia Djetten, François Meyer, Pierre Baudoz, Elsa Huby, Sebastian Rabien, Eckhard Sturm, Richard Davies
Solar and Stellar Astrophysics
K 1-6 is a photoionised ISM nebula shaped by a fast-moving hot white dwarf in a triple system
Jaroslav Merc, David Jones, Ana Escorza et al. (+22 more)
K 1-6 has long been classified as a planetary nebula (PN) hosting a binary central
star, yet it has remained poorly studied due to its faintness. The central
star exhibits pronounced photometric variability whose origin has so far been unclear. We aim to present a comprehensive characterisation of the K 1-6 system, including the physical properties of its
stellar components and the nature of the surrounding nebulosity. We conducted a multi-wavelength analysis combining optical and UV spectroscopy obtained with the Gran Telescopio Canarias, the Telescopio Nazionale Galileo, the Nordic Optical
Telescope, and the Hubble Space
Telescope. We also present long-term multi-band ground- and space-based photometry, including high-cadence data from the Transiting
Exoplanet Survey Satellite, narrow-band imaging, and the latest astrometric constraints from
Gaia. Our results show that the nebula is not a remnant PN, but instead consists of interstellar medium photoionised by a hot white
dwarf, which is relatively evolved. It has a cooling age of 1-2 Myr, implying that any original PN has long since dissipated. We further find that the central object is a hierarchical triple system, comprising an inner binary with an orbital period likely of the order of thousands of days and a distant tertiary companion on a timescale of tens of thousands of years. The optically dominant cool component of the inner binary is an inflated K-type
star displaying extreme
magnetic activity, including large-amplitude variability and flaring. Its properties resemble those of BY Dra-type binaries and Abell 35-type systems, and are difficult to reconcile with single-
star evolution, pointing instead to a history of binary interaction.
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All authors Jaroslav Merc, David Jones, Ana Escorza, Henri M. J. Boffin, Nicole Reindl, Michael Abdul-Masih, Thomas Masseron, Paulina Sowicka, Jan Kára, Jorge García-Rojas, Rafael A. García, Dinil B. Palakkatharappil, Quentin A. Parker, Albert A. Zijlstra, Diego Godoy-Rivera, Paul G. Beck, Savita Mathur, Montserrat Armas Padilla, Teo Muñoz Darias, Hana Kučáková, Marek Wolf, Kamil Hornoch, Petr Zasche, Rosa Clavero, Peter Goodhew
Solar and Stellar Astrophysics
Inferring 3D Coronal Magnetic Fields through Seismology-assisted Inversions of $IQU$-only Spectropolarimetric Observations
Alin Razvan Paraschiv
The routine measurement of the Stokes $IQUV$ signals of emission lines in the
solar corona is still a challenging endeavor, particularly for observations using small-aperture instruments. Therefore, recent studies have explored the use of coronal seismology and propagating Alfvénic waves as alternative diagnostics of the coronal
magnetic field. In particular, Z. Yang et al. showed that plane-of-sky (POS) phase-speed measurements provide a direct and consistent diagnostic of the POS
magnetic-field component (B$_{\text{POS}}$). Building on recent theoretical advances in
solar coronal polarization, we devise a novel inversion scheme and extended the CLEDB software package to exploit Stokes $IQU$ observations of two coronal emission lines combined with coronal seismology-derived B$_{\text{POS}}$ estimations. Using this framework, we perform a comprehensive statistical analysis demonstrating that this combination of diagnostics allows us to infer both
magnetic-field orientation and strength with an accuracy comparable to that of Stokes $IQUV$ spectropolarimetry. This type of diagnostics is particularly suited for the Fe xiii 1074.7 and 1079.8 nm line pair routinely observed by new-generation instruments such as DKIST Cryo-NIRSP, DL-NIRSP, MLSO CoMP/UCoMP, and targeted by the future COSMO and CORSAIR efforts.
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Solar and Stellar Astrophysics
Southern massive stars at high angular resolution: WR 25 is a massive hierarchical triple system
K. Deshmukh, L. Mahy, H. Sana et al. (+6 more)
WR 25 is a massive colliding-wind binary in the Carina nebula comprising a WN6ha primary with an O5 companion in an eccentric 208-d orbit. Recent spectroscopic analysis estimates the total binary mass to approach $100\,M_\odot$, and a primary-to-secondary mass ratio of $q= M_1/M_2\approx2$. The presence of additional spectroscopic signatures from a third, intruder
star was also noted, making it a candidate hierarchical triple system. In this study, we present a VLTI/PIONIER interferometric observation of WR 25, spatially resolving all three components for the first time. For the inner WN6ha + O5 binary, we find an angular separation of $1.68\pm0.02$ milliarcseconds (mas). Leveraging the fortunate timing of the VLTI observation, which was obtained when the two components were passing the line of nodes, we determined the semi-major axis $a=3.11\pm0.20$ au. Subsequently, the newly constrained total dynamical binary mass is $93\pm18\,M_\odot$, with a primary mass $M_1=62\pm13\, M_\odot$ and secondary mass $M_2=31\pm7\, M_\odot$. We detect the tertiary with an angular separation of $27.69\pm0.02$ mas from the primary, with a chance
alignment probability lower than $10^{-4}$. Using newly obtained brightness ratios between all components, we revisit archival spectroscopic data of WR 25 to disentangle spectra for individual components and derive their
stellar parameters. The tertiary, which has a spectral type O7, is coeval with the inner binary and has an evolutionary mass $M_3=25.6^{+2.8}_{-2.3}\,M_\odot$. Based on simulations, we estimate the tertiary period to be in the range 19 - 82 yr. The newly confirmed triple nature of WR 25 makes it an important
benchmark system to measure accurate dynamical masses of the inner binary and potentially the tertiary, to calibrate
stellar evolution and atmosphere models, and to study its formation and stability as a hierarchical triple system.
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All authors K. Deshmukh, L. Mahy, H. Sana, A. J. Frost, E. Gosset, C. Lanthermann, J.-B. LeBouquin, D. Pauli, T. Shenar
Instrumentation and Methods for Astrophysics
The MICADO first light imager for the ELT: an overview of the RAM analysis and consequent design and maintenance strategy
Federico Biondi, Yann Clénet, Patrick Caillier et al. (+7 more)
MICADO is a cryogenic near infrared Multi-AO Imaging Camera and Spectrometer developed for the first light operations at the ELT. It will operate in a "Standalone" configuration with a Single Conjugate Adaptive Optics module for a nominal period of two years. After this time, the system will be re-arranged in the "MICADO-MORFEO" configuration, being able to switch between the SCAO and a Multi Conjugate Adaptive Optics module in the later phase of the project. The lifetime requirement of minimum ten years, together with other demanding requisites about its availability and reliability triggered a meticulous FMECA analysis mainly focused on developing robust maintenance strategies. In this paper, we outline the assumptions and the boundaries of the MICADO RAM analysis, a collaborative effort involving the Max Planck Institute for the Extraterrestrial Physics, the Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique and the European Southern Observatory, starting from the input provided by all MICADO partners. We describe how RAM aspects drove some design choices as well as the selection and use of components. We report the preventive and predictive maintenance strategies, which we considered to minimize the risk of instrument downtime in the high cost operational context of the ELT.
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All authors Federico Biondi, Yann Clénet, Patrick Caillier, Veronika Wimmer, Tristan Buey, Luis Neumeier, Florian Lang, Sebastian Rabien, Eckhard Sturm, Richard Davies
High Energy Astrophysical Phenomena
EP-FXT Observations of Abell 1795: X-ray properties and structure out to $R_{200}$
Y. Tang, S.M. Jia, H.H. Zhao et al. (+20 more)
We present deep X-ray observations of the nearby X-ray-luminous
galaxy cluster Abell 1795 obtained with the Einstein Probe Follow-up X-ray
Telescope EP-FXT, with a total exposure time of $\sim 480$ ks. Exploiting the large field of view and low particle background of EP-FXT, we directly measured the radial temperature profile of A1795 out to $R_{200}$ with full azimuthal coverage, which was shown to increase in line with the radius within 6' and then gradually decline toward larger radii. The surface-brightness residual map and 2D thermodynamic maps reveal a clockwise spiral structure extending from the cluster core towards the south-east, which traces low-temperature and low-
entropy gas, which is also consistent with sloshing-induced cold fronts. In the north-west, the surface-brightness-enhanced region exhibits an arc-like high-temperature feature and both the temperature-derived and density-derived Mach numbers support the assumption that it is a weak shock. These substructures can be explained by a binary merger scenario: the perturbing subcluster induces sloshing during its first passage past the primary core and its subsequent return passage through the ICM might drive the shock towards the north-west. Our results indicate that relaxed
galaxy clusters such as A1795 might still retain signatures of dynamical activity.
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All authors Y. Tang, S.M. Jia, H.H. Zhao, C.K. Li, H. Yu, Y. Chen, S.S. Weng, X.Y. Zheng, H. Feng, L.M. Song, C.Z. Liu, F.J. Lu, S.N. Zhang, W.M. Yuan, S. Andreon, J.F. Wang, W.W. Cui, J. Guan, C.C. Jin, Y. Liu, J. Zhang, H.S. Zhao, X.F. Zhao
Instrumentation and Methods for Astrophysics
The MICADO first-light imager for the ELT: first steps of the SCAO system MAIT
Yann Clénet, Eric Gendron, Fabrice Vidal et al. (+39 more)
MICADO is the ELT first light instrument, an imager working at the diffraction limit of the
telescope thanks to two adaptive optics (AO) modes: a single conjugate one (SCAO), available at the instrument first light and developed by the MICADO consortium, and a multi conjugate one (MCAO), developed by the MORFEO consortium. Although the project final design review process is about to be completed, the review board and ESO acknowledged that "the review of the final design can be considered complete for the majority of the MICADO sub-systems" and agreed that MICADO can start manufacturing. For the MICADO SCAO module, we have started the manufacturing of several parts: the majority of the SCAO optics and of the SCAO mechanics, the real-time computer software and the instrument control software. This manufacturing is ordered in several steps to allow the progressive integration of a first full AO close loop with the final SCAO parts. In this contribution, we will focus on the first two steps: on our AO Sésame bench and the so-called "beta flat configuration". We will present the status of this manufacturing and the first results obtained.
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All authors Yann Clénet, Eric Gendron, Fabrice Vidal, Mathieu Cohen, Frédéric Chapron, Arnaud Sevin, Tristan Buey, Sylvain Guieu, Sylvestre Taburet, Bruno Borgo, Jean-Michel Huet, Olivier Dupuis, Kévin Cloiseau, Alexandre Blin, Julien Gaudemard, Claude Collin, Julian Porras, Florian Ferreira, Jordan Raffard, Fanny Chemla, Vincent Lapeyrère, Eric Meyer, Nicolas Gautherot, Emmanuel Tisserand, Hervé Locatelli, Gilles Fasola, Lahoucine Ghouchou, Camille Gennet, François Meyer, Amal Zidi, Caroline Kulcsár, Henri-François Raynaud, Benoit Sassolas, Laurent Pinard, Christophe Michel, Damien Gratadour, Roderick Dembet, Pierre Baudoz, Elsa Huby, Sebastian Rabien, Eckhard Sturm, Richard Davies
High Energy Astrophysical Phenomena
Supernova Neutrinos and the Origin of Biomolecular Homochirality
Amirmasoud Jannat, Soroush Shakeri and Farhad Shahbazi
We investigate the role of parity-violating interactions between
supernova neutrinos and
chiral molecules in nearby interstellar molecular clouds as a potential source of biomolecular homochirality. We introduce
neutrino interactions into the autocatalytic chemical reactions in a far-from-
equilibrium noise-induced system. These interactions create a directional bias between L and D enantiomers in the racemization reactions, which is amplified by autocatalysis and
stochastic fluctuations. We solve the
stochastic equations within the Ito sense to obtain the dynamics of the probability distribution of the enantiomeric excesses, offering an astrophysical scenario for the delivery of homochirality seeds to Earth by meteorites. In spite of the weak interactions of
supernova neutrinos, our framework introduces an amplification mechanism to yield a considerable enantiomeric excess of more than $10\%$, in agreement with the latest chemical analysis of the meteorites. Moreover, we scan over the parameter space of the model, inferring from the observational values in order to explore the window of opportunity to generate the initial seeds of homochiral states in interstellar molecular clouds.
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Instrumentation and Methods for Astrophysics
Enhanced wavefront sensing for the Roman Coronagraph Instrument: Gaussian probes and compact model validation
Lukas Delaye, Iva Laginja, Pierre Baudoz et al. (+10 more)
The Coronagraph Instrument on the Roman Space
Telescope will be the first space-based system to demonstrate closed-loop focal-plane wavefront sensing and control, a key step towards the Habitable Worlds Observatory. Beyond the baseline Hybrid Lyot Coronagraph, "enhanced modes" are being developed to improve efficiency and science yield. One such mode uses Gaussian probes for electric field estimation, extending the linear regime and allowing higher probe amplitudes. This may increase signal-to-noise, reduce exposure time, accelerate dark hole convergence, and extend operation to
stars as faint as $V\sim5$. For those reasons, it was selected by the Coronagraph Community Participation Program's Hardware Working Group as the first technology demonstration carried out on Roman in early 2027. We present numerical simulations using a noise-free compact software model, which demonstrate the benefits of replacing the nominal probes with Gaussian probes.
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All authors Lukas Delaye, Iva Laginja, Pierre Baudoz, Axel Potier, Johan Mazoyer, Raphaël Galicher, Susan F. Redmond, Alexis Lau, A. J. Riggs, Dan Sirbu, Emiel H. Por, Rémi Soummer, Laurent Pueyo