CyberSec Research

The beam-crossing is a novel technique aimed at reducing residual tropospheric Doppler noise for microwave radiometer calibrations. In this work, we report the findings of the first test of this technique using ESA's Tropospheric Delay Calibration System (TDCS) at the complex in Malargue. The data consists in 14 tracking passes of the BepiColombo spacecraft collected between October 2023 and March 2024 during two separate test campaigns. We analyzed the performance of the beam-crossing technique and compared it with the nominal radiometer pointing through the analysis of the Doppler residuals extracted from the orbit determination process. Results show that the beam-crossing performed similarly to the standard pointing, with modest noise reductions and improved stability only at time scales between 100 s and 300 s. Key factors affecting the results include the antenna elevation and the boundary layer height, indicating the need to revisit initial test assumptions, which comprised a fixed boundary layer. Furthermore, comparing the beam-crossing test results with those obtained during the first two BepiColombo superior solar conjunction experiments highlights a potential application of this technique during periods of solar conjunction. However, technical challenges, adverse weather, and limited Ka-band transponder use, reduced the number of analyzed tracking passes. Future studies should therefore expand the dataset to consolidate the results. Furthermore new theoretical studies and test campaigns should elaborate on the selection process for the optimal crossing height.

We report optical evidence of cesium (Cs) evaporation from a bialkali (SbKCs) photo- cathode during controlled heating of a photomultiplier tube (PMT). A DFB laser scanned across the 852.113 nm Cs D2 line reveals absorption features only above 60 degrees Celsius, indicating thermal desorption. The absorption correlates with temperature and offers a non-invasive method to monitor photocathode degradation in sealed detectors.

Local Universe dwarf galaxies are both cosmological and mass assembly probes. Deep surveys have enabled the study of these objects down to the low surface brightness (LSB) regime. In this paper, we estimate Euclid's dwarf detection capabilities as well as limits of its MERge processing function (MER pipeline), responsible for producing the stacked mosaics and final catalogues. To do this, we inject mock dwarf galaxies in a real Euclid Wide Survey (EWS) field in the VIS band and compare the input catalogue to the final MER catalogue. The mock dwarf galaxies are generated with simple S\'ersic models and structural parameters extracted from observed dwarf galaxy property catalogues. To characterize the detected dwarfs, we use the mean surface brightness inside the effective radius SBe (in mag arcsec-2). The final MER catalogues achieve completenesses of 91 % for SBe in [21, 24], and 54 % for SBe in [24, 28]. These numbers do not take into account possible contaminants, including confusion with background galaxies at the location of the dwarfs. After taking into account those effects, they become respectively 86 % and 38 %. The MER pipeline performs a final local background subtraction with small mesh size, leading to a flux loss for galaxies with Re > 10". By using the final MER mosaics and reinjecting this local background, we obtain an image in which we recover reliable photometric properties for objects under the arcminute scale. This background-reinjected product is thus suitable for the study of Local Universe dwarf galaxies. Euclid's data reduction pipeline serves as a test bed for other deep surveys, particularly regarding background subtraction methods, a key issue in LSB science.

Space radiation is one of the major obstacles to space exploration. If not mitigated, radiation can interact both with biological and electronic systems, inducing damage and posing significant risk to space missions. Countermeasures can only be studied effectively with ground-based accelerators that act as a proxy for space radiation, typically with a harsher radiation field that worsen the effects of space radiation. Following an in-silico design and optimization process we have developed a galactic cosmic ray (GCR) simulator using a hybrid active-passive methodology. In this approach, the primary beam energy is actively switched and the beam interacts with specifically designed passive modulators. In this paper, we present the implementation of such a GCR simulator and its experimental microdosimetric characterization. Measuring the GCR field is of paramount importance, both before providing it to the user as a validated radiation field and for achieving the best possible radiation description. The issue is addressed in this paper by using a tissue-equivalent proportional counter to measure radiation quality and by comparing experimental measurements with Monte Carlo simulations. In conclusion, we will demonstrate the GCR simulator's capability to reproduce a GCR field.

Intensity interferometry (II) offers a powerful means to observe stellar objects with a high resolution. In this work, we demonstrate that II can also probe internal stellar kinematics by revealing a time-asymmetric Hanbury Brown and Twiss (HBT) effect, causing a measurable shift in the temporal correlation peak away from zero delay. We develop numerical models to simulate this effect for two distinct astrophysical scenarios: an emission-line circumstellar disk and an absorption-line binary system. Our simulations reveal a clear sensitivity of this temporal asymmetry to the system's inclination angle, velocity symmetry, and internal dynamics. This suggests that, with sufficiently high time resolution, II can be used to extract quantitative information about internal kinematics, offering a new observational window on stellar dynamics.

While astronomical twilight closes the observing window for optical astronomers, the infrared sky remains dark even through sunrise, allowing IR astronomers to observe through twilight. The Slicer Combined with an Array of Lenslets for Exoplanet Spectroscopy (SCALES) instrument is a 2-5 micron coronagraphic integral field spectrograph scheduled to arrive at Keck in early 2026. SCALES has the potential to execute exciting science and support the astronomical community and upcoming NASA missions through a dedicated cadenced twilight observing program. We estimate that the current twilight observing program on Keck conducts 18+-1 hours per year of science observations; a facilitized twilight observing program that is prioritized by the observatory could yield 151+-2 hours of science time per year. This work presents the scientific motivation and high-level feasibility of two primary SCALES twilight science cases, monitoring of Solar System objects and a high-contrast imaging search for exoplanets around bright nearby stars, taking lessons from the existing NIRC2 and OSIRIS Twilight Zone program and considering increases in program scope. We also consider technical and operational challenges to overcome before the SCALES instrument begins its twilight observing program.

The CUbesat Solar Polarimeter (CUSP) project is a CubeSat mission planned for a launch in low-Earth orbit and aimed to measure the linear polarization of solar flares in the hard X-ray band by means of a Compton scattering polarimeter. CUSP will allow us to study the magnetic reconnection and particle acceleration in the flaring magnetic structures of our star. CUSP is a project in the framework of the Alcor Program of the Italian Space Agency aimed at developing new CubeSat missions. It is undergoing a 12-month Phase B that started in December 2024. The Compton polarimeter on board CUSP is composed of two acquisition chains based on plastic scintillators read out by Multi-Anode PhotoMultiplier Tubes for the scatterer part and GAGG crystals coupled to Avalanche PhotoDiodes for the absorbers. An event coincident between the two readout schemes will lead to a measurement of the incoming X-ray's azimuthal scattering angle, linked to the polarization of the solar flare in a statistical manner. The current status of the CUSP mission design, mission analysis, and payload scientific performance will be reported. The latter will be discussed based on preliminary laboratory results obtained in parallel with Geant4 simulations.

The surface array of the IceCube Neutrino Observatory, IceTop, measures cosmic rays in the PeV-EeV primary energy range. Stations comprising radio antennas and scintillation detectors will be added to enhance the existing surface detectors. A prototype station, consisting of eight scintillation detectors and three radio antennas, has been in operation in with the instrumentation in final design since the beginning of 2023. Radio signals from air showers are measured by antennas that are read-out when the trigger condition from the scintillation detectors is met. This contribution reports on air-shower coincidence measurements of these radio antennas with IceTop. Geometric shower parameters reconstructed from the radio antennas are compared with those from IceTop to determine the angular resolution. We also present details on the two new stations that were tested, deployed and commissioned with their respective data acquisition systems during the latest field season at the South Pole.

To achieve the sensitivity required to detect signals from neutral hydrogen from the Cosmic Dawn and Epoch of Reionisation it is critical to have a well-calibrated instrument which has a stable calibration over the course of the observation. Previous calibration methods do not explicitly use the time information available and make assumptions on the impedance matching of the reference sources. Here we present a new calibration method based on noise wave parameters which fits a calibration solution over time and frequency to the data, interpolating the solutions to the times at which the antenna is being measured. To test this method we simulate a dataset using measurements of the REACH receiver, modelling a low noise amplifier which is drifting over time. Fitting a polynomial surface in frequency and time to the simulated data demonstrates that we can remove the drift in the calibrated solution over time but leaves a chromatic residual. We further show that we can remove assumptions on the reflection coefficients of the reference noise source and the cold load, reducing degeneracies in the parameter fits. Applying this new calibration equation and surface fitting method to the simulated data removes the chromatic residual in the calibrated spectrum and recovers the parameters to within 0.06% of the truth and a 97% reduction in the RMSE of the spectrum of the validation source compared with previous calibration methods. For two parameters we report up to six times smaller fit error after the degeneracies are removed from the time-based calibration.

The field of gravitational wave (GW) detection is progressing rapidly, with several next-generation observatories on the horizon, including LISA. GW data is challenging to analyze due to highly variable signals shaped by source properties and the presence of complex noise. These factors emphasize the need for robust, advanced analysis tools. In this context, we have initiated the development of a low-latency GW detection pipeline based on quantum neural networks (QNNs). Previously, we demonstrated that QNNs can recognize GWs simulated using post-Newtonian approximations in the Newtonian limit. We then extended this work using data from the LISA Consortium, training QNNs to distinguish between noisy GW signals and pure noise. Currently, we are evaluating performance on the Sangria LISA Data Challenge dataset and comparing it against classical methods. Our results show that QNNs can reliably distinguish GW signals embedded in noise, achieving classification accuracies above 98\%. Notably, our QNN identified 5 out of 6 mergers in the Sangria blind dataset. The remaining merger, characterized by the lowest amplitude, highlights an area for future improvement in model sensitivity. This can potentially be addressed using additional mock training datasets, which we are preparing, and by testing different QNN architectures and ansatzes.

Current models of binary systems often depend on simplified approach of the radiation field, which are unlikely to accurately capture the complexities of asymmetric environments. We investigate the dynamical and chemical implications of a 3D asymmetric radiation field that accounts for the optical properties of sub-structures present in a protoplanetary disk, as well as the inclusion of a secondary radiation source in binary systems. We conducted a series of 3D-SPH hydrodynamical simulations using PHANTOM, coupled with the 3D Monte Carlo radiative transfer code MCFOST, to compute disc temperatures on-the-fly. We explored different binary-disk orientations (0$^o$ and 30$^o$) for an eccentric binary, along with a constant dust-to-gas ratio and dust as a mixture prescription. We also simulated an outburst event as an example of a drastic increase in luminosity. Heating from the secondary star inflates the outer disk, increasing the aspect ratio facing the companion by about 25% in inclined cases compared to 10% in coplanar ones. Dust settling in the mid-plane enhances extinction along the disk plane, making the coplanar case cooler than the inclined one on the side of the disk facing the companion. Besides, heating causes a shift in the snow line for species with freeze-out temperatures below 50 K, depending on the disk-binary inclination and binary phase. During outbursts, the aspect ratio doubles on the star-facing side and increases by 50% on the opposite side in inclined cases. The snow line shift would impact all the species considered in the outburst case. Disk heating in binaries depends on stellar properties, orbital phase, and disk local and global characteristics. This results in temperature asymmetries, especially during secondary star outbursts, leading to variations in aspect ratio and snow lines that can affect chemistry and planet formation.

In this work, we explore a possible application of a machine learning classifier for candidate events in a template-based search for gravitational-wave (GW) signals from various compact system sources. We analyze data from the O3a and O3b data acquisition campaign, during which the sensitivity of ground-based detectors is limited by real non-Gaussian noise transient. The state-of-the-art searches for such signals tipically rely on the signal-to-noise ratio (SNR) and a chi-square test to assess the consistency of the signal with an inspiral template. In addition, a combination of these and other statistical properties are used to build a 're-weighted SNR' statistics. We evaluate a Random Forest classifiers on a set of double-coincidence events identified using the MBTA pipeline. The new classifier achieves a modest but consistent increase in event detection at low false positive rates relative to the standard search. Using the output statistics from the Random Forest classifier, we compute the probability of astrophysical origin for each event, denoted as $p_\mathrm{astro}$. This is then evaluated for the events listed in existing catalogs, with results consistent with those from the standard search. Finally, we search for new possible candidates using this new statistics, with $p_\mathrm{astro} > 0.5$, obtaining a new subthreshold candidate (IFAR =0.05) event at $gps: 1240423628$ .

An international collaboration composed of Italian, Japanese, Spanish and Swiss institutes, is developing the advanced camera (AdvCam), the next-generation camera for Imaging Atmospheric Cherenkov Telescopes, designed specifically for the Large-Sized Telescopes (LST) of the Cherenkov Telescope Array Observatory. AdvCam incorporates cutting-edge Silicon Photomultipliers (SiPMs) and a fully digital readout system, setting new standards for performance and efficiency. The upgraded camera will feature four times more pixels for the same field of view as the existing PMT-based camera, enabling finer image resolution and significantly improving angular precision and background noise rejection. To cope with the increase in number of pixels, many technological challenges are being tackled, from low power and high speed integrated chip design to real-time data processing on hardware accelerators. This technological leap will lower the energy threshold by allowing operation at lower observation threshold and providing brighter images. The increase in effective area, angular and energy resolution will enhance the sensitivity, unlocking new potential for gamma-ray astronomy. In this work, we present the performance of the AdvCam's core building blocks and its innovative architecture capable of enabling unprecedented triggering capabilities. We also showcase the latest performance results based on Monte-Carlo data that has been tuned to reflect the latest stages of the on-going technological developments, highlighting the transformative capabilities of this next-generation instrument.

The goal of this study is to analyze the photometric properties of Deimos using Mars Express (MEX) observations, to improve the photometric properties and provide new insights into the texture and composition of the surface of Deimos, in preparation for the MMX mission. We analyzed the data obtained by the HRSC and the SRC cameras onboard MEX. The HRSC data, obtained through the use of four filters (blue, green, red, IR), provides 390 to 800 m/px resolution, while the SRC data reach 85 to 300 m/px and cover a wide phase angle range (0.06-138{\deg}). We performed the disk-integrated and disk-resolved photometric analysis using the Hapke model. The Deimos surface is dark and predominantly backscattering, with a single-scattering albedo (SSA) value (6.8%-7.5%) comparable to Phobos. The Deimos phase curve shows a strong opposition effect due to shadow-hiding, with negligible coherent backscattering. The amplitude and the half-width of the shadow-hiding opposition surge were found to be 2.14 +/- 0.14 and 0.065 +/- 0.004, respectively. We found a high porosity of 86% at the top-layer surface, consistent with complex-shaped grains or fractal aggregates, suggesting a thick dust layer. We did not observe significant variations of the opposition surge across the surface. A blue unit on Deimos, located on streamers of the equatorial ridge, shows reflectance increases up to 58%, and a spectral slope decrease of 50% in comparison with the average surface. This blue unit may be due to a different texture of the surface between the two units, with finer grain and/or higher porosity. Deimos photometric properties, including SSA, opposition surge, and phase integral, are very similar to Phobos. The presence of a blue unit on Deimos reinforces the idea that the Martian moons have a common origin, making the capture of two different bodies with such similar properties unlikely.

Recent advances in ground-based astronomy have made it possible to create optical telescopes with primary mirrors up to 40 m in size. With growing mirror diameter, the suppression of non-atmospheric disturbances becomes increasingly important. Precise knowledge of the movement of telescope mirrors is essential for understanding and compensating for vibration-based perturbations. A model from VLT accelerometer data for each individual mirror is developed, while the influence of wind buffeting is accounted for by a von Karman wind model. To describe the relevant rigid body motion, we consider the piston, tip and tilt modes of the mirrors. The identification is validated by comparing the power spectral density of the measured and identified modes. Additionally, we assess the robustness of the approach by calculating the identification error over different sections of the data. The study indicates that the employed methods are adequate for the identification of modal telescope vibrations. It is anticipated that said findings will serve as a significant foundation for the development of advanced model-based AO controllers for large telescopes, such as linear quadratic Gaussian control.

The performance of future observatories such as the Extremely Large Telescope is mainly limited by atmospheric turbulence and structural vibrations of the optical assembly. To further enhance the mitigation performance of adaptive optics, real-time information about the disturbances acting on the control loop is needed. Current systems therefore employ a combination of wavefront sensor- and accelerometer-based filters. In this work, methods using only data from natural- and laser guide star (NGS, LGS) measurements are presented, as telescopes like the Very Large Telescope already have multiple fast and high-resolution wavefront sensors installed. This approach also avoids the costly installation and operation of additional accelerometers on the optical elements. We introduce two innovative disturbance observer schemes to sense both turbulence and vibration information. A multi-rate estimator for atmospheric influences is based on Kalman filter theory and can incorporate NGS and LGS signals at different loop rates. The estimator for structural perturbations uses Gaussian process regression and can be implemented in an offline and online configuration. We validate the filter designs with data from a realistic end-to-end adaptive optics model with randomly generated turbulence and vibrations. The simulation is fed with on-sky data from the Adaptive Optics Facility of the Very Large Telescope. The presented disturbance observer schemes demonstrate promising results and may be considered as potential alternatives or extensions to existing techniques such as linear-quadratic controllers with Kalman filtering (LQG).

Resolving high-contrast targets is a fundamental yet highly challenging task in astronomy. Using quantum estimation theory, we demonstrate that the ultimate limit for estimating the separation between two unequal-brightness thermal sources via interferometry remains constant, enabling the potential for superresolution. We give a comparative analysis of two primary stellar interferometric schemes: amplitude interferometry and intensity interferometry. Notably, the nulling strategy employed in amplitude interferometry, a configuration specifically proposed for exoplanet detection by leveraging destructive interference to suppress the brighter source, is quantum optimal for separation estimation. While intensity interferometry is less effective than amplitude interferometry in lossless scenarios and fails to achieve superresolution, it becomes competitive when optical loss in large-scale interferometry is considered. By applying these methodologies to modern stellar interferometry, we highlight the promise of large-scale interferometry for advancing high-resolution astronomical observation.

Our ability to observe, detect, and characterize exoplanetary atmospheres has grown by leaps and bounds over the last 20 years, aided largely by developments in astronomical instrumentation; improvements in data analysis techniques; and an increase in the sophistication and availability of spectroscopic models. Over this time, detections have been made for a number of important molecular species across a range of wavelengths and spectral resolutions. Ground-based observations at high resolution are particularly valuable due to the high contrast achievable between the stellar spectral continuum and the cores of resolved exoplanet absorption features. However, the model-independent retrieval of such features remains a major hurdle in data analysis, with traditional methods being limited by both the choice of algorithm used to remove the non-exoplanetary components of the signal, as well as the accuracy of model template spectra used for cross-correlation. Here we present a new algorithm TSD (Transmission Spectroscopy Decomposition) formulated as an inverse problem in order to minimize the number of assumptions and theoretically modelled components included in the retrieval. Instead of cross-correlation with pre-computed template exoplanet spectra, we rely on high spectral resolution and instrument stability to distinguish between the stellar, exoplanetary, and telluric components and velocity frames in the sequence of absorption spectra taken during multiple transits. We demonstrate the performance of our new method using both simulated and real K band observations from ESO's VLT/CRIRES+ instrument, and present results obtained from two transits of the highly-inflated super-Neptune WASP-107 b which orbits a nearby K7V star.