Angular Extent Research Articles

Spatial distributions of 13CO and CS in a carbon-rich AGB star IRC+10216

IRC+10216 is the typical carbon-rich asymptotic giant branch star, and more than 100 species have been observed in its circumstellar envelope so far. The use of interferometric arrays to map molecular emission in this source has been widely reported, but to study the angular extent of molecular emission, single-dish mapping must be employed. We report here the mapping of the 13CO J = 1–0 and CS J = 2–1 lines towards IRC+10216 using the 13.7 m mm-wave radio telescope at Purple Mountain Observatory. As far as we know, these maps are the largest published 13CO J = 2–1 and CS J = 2–1 images to date. Both molecules have roughly spherically symmetric distribution, with 13CO having an emission radius of over 80″and CS extending up to ∼50″. Assuming that the two molecules are in local thermodynamic equilibrium, the column density and fractional abundance relative to H2 for 13CO and the lower limits for CS are obtained. They are 4.35 × 1016 cm−2 and > 4.72 × 1014 cm−2, and 5.25 × 10−5 and > 2.56 × 10−7 for 13CO and CS, respectively.

Can Baseline Parapapillary Atrophy Morphology Predict Future Glaucoma Progression?—An OCT Glaucoma Imaging Study

PurposeTo investigate glaucoma progression based on Optical Coherence Tomography (OCT) Guided Progression Analysis (GPA) according to baseline β-zone parapapillary atrophy (PPA) morphology in glaucoma patients. DesignRetrospective cohort study. MethodsPatients over 20 years of age who had been diagnosed with primary open-angle glaucoma (POAG) at Seoul National University Hospital, Seoul, Korea between 2010 and 2020. This study included POAG patients with a minimum of 5 years of follow-up. We quantitatively measured the baseline β-zone PPA parameters, classified β-zone PPA morphology according to new classification standard we created and analyzed the corresponding GPA progression of the retinal nerve fiber layer (RNFL). ResultsA total of 210 patients with POAG (mean age: 53.8 years) were enrolled in the study. The mean follow-up period was 9.8 years. The average value of the baseline mean deviation in visual field perimetry was -2.48 dB. Longer radial extent and larger angular extent of β-zone PPA were significantly associated with progression on GPA, as was the presence of disc hemorrhage. Among the 4 classified β-zone PPA morphologies (Crescent type 1 & 2, Solar-eclipse type 1 & 2), the Solar-eclipse type 2 group showed the highest progression. A Kaplan-Meier survival analysis demonstrated significant differences among the 4 types. ConclusionsThe larger the radial and angular extents of β-zone PPA, the more progression that was shown on OCT GPA. Furthermore, significant differences in progression were noted based on the morphological type of β-zone PPA. Our findings indicate that baseline β-zone PPA parameters and morphology are valuable predictors of future glaucoma progression.

A Type Ia Supernova near a Globular Cluster in the Early-type Galaxy NGC 5353

No progenitor of a Type Ia supernova (SN Ia) is known, but in old-population early-type galaxies, one may find SNe Ia associated with globular clusters, yielding a population age and metallicity. It also provides insight into the formation path and the SN enhancement rate in globular clusters. We sought to find such associations and identified SN 2019ein to be within the ground-based optical positional uncertainty of a globular cluster candidate within the early-type galaxy NGC 5353 at D ≈ 30 Mpc. We reduced the positional uncertainties by obtaining Hubble Space Telescope images with the Advanced Camera for Surveys, using filters F475W and F814W obtained in 2020 June. We find that the globular cluster candidate has a magnitude, color, and angular extent that are consistent with it being a typical globular cluster. The separation between the globular cluster and SN 2019ein is 0.″43, or 59 pc in projection. The chance occurrence with a random globular cluster is ≈3%, favoring but not proving an association. If the SN progenitor originated in the globular cluster, one scenario is that SN 2019ein was previously a double-degenerate white dwarf binary that was dynamically ejected from the globular cluster and exploded within 10 Myr; models do not predict this to be common. Another, but less likely scenario is where the progenitor remained bound to the globular cluster, allowing the double-degenerate binary to inspiral on a much longer timescale before producing an SN.

Physics-based prognostics of rolling-element bearings: The equivalent damaged volume algorithm

This paper introduces a novel parameter related to bearing degradation, namely the Equivalent Damaged Volume (EDV). An algorithm capable of extracting EDV values from experimental data is detailed. To this end, the proposed technique relies on the comparison between experimental and numerical signals. The former are the result of an extensive campaign of run-to-failure tests performed on a dedicated test rig. On the other hand, the latter are obtained by means of a lumped parameter model that accounts for the angular extent and the depth of either localized or extended defects. The potential of this novel technique is demonstrated by exploiting the values obtained by the algorithm as inputs for a prognostic model. In particular, the developed model aims at predicting the time until a certain threshold on the equivalent damaged volume is crossed, regardless of the applied load and the shaft rotation speed. The advantages and downsides introduced by the proposed approach are thoroughly discussed by providing examples based on real degradation histories.

Characteristics of beta parapapillary atrophy in primary angle-closure suspect

ObjectiveTo investigate the characteristics of beta parapapillary atrophy (β-PPA) in patients with primary angle-closure suspect (PACS).Methods and analysisIn total, 215 and 259 eyes with PACS and non-PACS (NPACS), respectively, were...

Deep synthesis and exploration of omnidirectional stereoscopic environments from a single surround-view panoramic image

We introduce an innovative approach to automatically generate and explore immersive stereoscopic indoor environments derived from a single monoscopic panoramic image in an equirectangular format. Once per 360° shot, we estimate the per-pixel depth using a gated deep network architecture. Subsequently, we synthesize a collection of panoramic slices through reprojection and view-synthesis employing deep learning. These slices are distributed around the central viewpoint, with each slice’s projection center placed on the circular path covered by the eyes during a head rotation. Furthermore, each slice encompasses an angular extent sufficient to accommodate the potential gaze directions of both the left and right eye and to provide context for reconstruction. For fast display, a stereoscopic multiple-center-of-projection stereo pair in equirectangular format is composed by suitably blending the precomputed slices. At run-time, the pair is loaded in a lightweight WebXR viewer that responds to head rotations, offering both motion and stereo cues. The approach combines and extends state-of-the-art data-driven techniques, incorporating several innovations. Notably, a gated architecture is introduced for panoramic monocular depth estimation. Leveraging the predicted depth, the same gated architecture is then applied to the re-projection of visible pixels, facilitating the inpainting of occluded and disoccluded regions by incorporating a mixed Generative Adversarial Network (GAN). The resulting system works on a variety of available VR headsets and can serve as a base component for immersive applications. We demonstrate our technology on several indoor scenes from publicly available data.

High resolution modelling of [CII], [CI], [OIII], and CO line emission from the interstellar medium and circumgalactic medium of a star-forming galaxy at z ∼ 6.5

The circumgalactic medium (CGM) is a crucial component of galaxy evolution, but thus far its physical properties are highly unconstrained. As of yet, no cosmological simulation has reached convergence when it comes to constraining the cold and dense gas fraction of the CGM. Such components are also challenging to observe directly, as they require sub-millimetre (sub-mm) instruments with a high sensitivity to extended and mostly diffuse emission. We present a state-of-the-art theoretical effort at modelling the [CII] 158 μm, [CI](1−0) 609 μm, [CI](2−1) 370 μm, CO(3−2) 867 μm, and [OIII] 88 μm line emissions that arise from the interstellar medium (ISM) and CGM of galaxies, with the goal of studying the contribution from different cold (T < 104 K) components of galaxy halos. We used the high-resolution cosmological zoom-in simulation PONOS (mgas = 883.4 M⊙), which represents a typical star-forming galaxy system at z = 6.5, composed of a main disc with stellar mass M* = 2 × 109 M⊙ that is undergoing a major merger. We adopted different modelling approaches based on the photoionisation code CLOUDY. Our fiducial model uses radiative transfer post-processing with RAMSES-RT and KROME (KRAMSES-RT) to create more realistic far-ultraviolet (FUV) radiation fields, which we then compared to other sub-grid modelling approaches adopted in the literature. We find significant differences in the luminosity and in the contribution of different gas phases and galaxy components between the different modelling approaches. [CII] is the least model-dependant gas tracer, while [CI](1−0) and CO(3−2) are very model-sensitive. In all models, we find a significant contribution to the emission of [CII] (up to ∼10%) and [OIII] (up to ∼21%) from the CGM. Our fiducial global radiative transfer (RT) model produces a lower density, T ∼ 104 K tail of [CII] emission that is not seen in the other more simplistic models and that resides entirely in the CGM, ionised by the FUV background and producing the extended halos observed in [CII] at high-z. Notably, [CII] and [OIII] trace different regions of the CGM: [CII] arises from an accreting filament and from the tidal tails connecting the main disc and its merging satellites, while [OIII] traces a puffy halo surrounding the main disc, probably linked to supernova feedback. We discuss our results in the context of sub-mm observations. Using simulated spectra and mock maps, we show that, despite the rather compact angular extent of PONOS’s CGM, deep ALMA observations would not detect this component, even in [CII] which is the brightest available tracer. Instead, a next generation single-dish observatory such as the Atacama Large Aperture Submillimeter Telescope (AtLAST) could detect PONOS’ CGM in [CII] at a high signal-to-noise ratio, and possibly even in [OIII].

WiFeS observations of nearby southern Type Ia supernova host galaxies

Abstract We present high-resolution observations of nearby ( $z\lesssim0.1$ ) galaxies that have hosted Type Ia supernovae to measure systemic spectroscopic redshifts using the wide field spectrograph (WiFeS) instrument on the Australian National University 2.3 m telescope at Siding Spring Observatory. While most of the galaxies targeted have previous spectroscopic redshifts, we provide demonstrably more accurate and precise redshifts with competitive uncertainties, motivated by potential systematic errors that could bias estimates of the Hubble constant ( $H_0$ ). The WiFeS instrument is remarkably stable; after calibration, the wavelength solution varies by $\lesssim$ 0.5 Å in red and blue with no evidence of a trend over the course of several years. By virtue of the $25\times 38$ arcsec field of view, we are always able to measure the redshift of the galactic core, or the entire galaxy in the cases where its angular extent is smaller than the field of view, reducing any errors due to galaxy rotation. We observed 185 southern SN Ia host galaxies and measured the redshift of each via at least one spatial region of (a) the core and (b) the average over the full-field/entire galaxy. Overall, we find stochastic differences between historical redshifts and our measured redshifts on the order of $\lesssim10^{-3}$ with a mean offset of 4.3 ${\times 10^{-5}}$ and normalised median absolute deviation of 1.2 ${\times 10^{-4}}$ . We show that a systematic redshift offset at this level is not enough to bias cosmology, as $H_0$ shifts by $+0.1$ km s $^{-1}$ Mpc $^{-1}$ when we replace Pantheon+ redshifts with our own, but the occasional large differences are interesting to note.

ATOMIUM: Molecular inventory of 17 oxygen-rich evolved stars observed with ALMA

Context. The dusty winds of cool evolved stars are a major contributor of the newly synthesised material enriching the Galaxy and future generations of stars. However, the details of the physics and chemistry behind dust formation and wind launching have yet to be pinpointed. Recent spatially resolved observations show the importance of gaining a more comprehensive view of the circumstellar chemistry, but a comparative study of the intricate interplay between chemistry and physics is still difficult because observational details such as frequencies and angular resolutions are rarely comparable. Aims. Aiming to overcome these deficiencies, ATOMIUM is an ALMA Large Programme to study the physics and chemistry of the circumstellar envelopes of a diverse set of oxygen-rich evolved stars under homogeneous observing conditions at three angular resolutions between ~0.02″−1.4″. Here we summarize the molecular inventory of these sources, and the correlations between stellar parameters and molecular content. Methods. Seventeen oxygen-rich or S-type asymptotic giant branch (AGB) and red supergiant (RSG) stars have been observed in several tunings with ALMA Band 6, targeting a range of molecules to probe the circumstellar envelope and especially the chemistry of dust formation close to the star. We systematically assigned the molecular carriers of the spectral lines and measured their spectroscopic parameters and the angular extent of the emission of each line from integrated intensity maps. Results. Across the ATOMIUM sample, we detect 291 transitions of 24 different molecules and their isotopologues. This includes several first detections in oxygen-rich AGB/RSG stars: PO v = 1, SO2 v1 = 1 and v2 = 2, and several high energy H2O transitions. We also find several first detections in S-type AGB stars: vibrationally excited HCN v2 = 2,3 and SiS v = 4,5,6, as well as first detections of the molecules SiC, AlCl, and AlF in W Aql. Overall, we find strong correlations between the following molecular pairs: CS and SiS, CS and AlF, NaCl and KCl, AlO and SO, SO2 and SO, and SO2 and H2O; meaning both molecules tend to have more detected emission lines in the same sources. The measured isotopic ratios of Si and S are found to be consistent with previous measurements, except for an anomalously high 29Si/30Si ratio of 4 ± 1 in the RSG VX Sgr. Conclusions. This paper presents the overall molecular inventory and an initial analysis of the large ATOMIUM dataset, laying the groundwork for future work deriving molecular abundances and abundance profiles using radiative transfer modeling which will provide more rigorous tests for chemical models.

Dual series solution for the standardized ISRM Brazilian disc test modelled as an advancing contact problem

A new analytical solution is found for the stress and displacement fields in a standardized ISRM Brazilian disc test with curved jaws, based on the solution of a set of dual trigonometric series. The disc is assumed to be linear elastic and isotropic and in frictionless advancing contact with the two jaws assumed as rigid, under plane stress loading conditions. Use is made of the Michell solution for an elastic disc in polar coordinates, whose coefficients are found by imposing the mixed boundary conditions along the disc rim, both along the free surface and the contact region. The problem is first reduced to a set of dual trigonometric series and then to a linear system of infinite equations, which is solved by truncation. The non-linear relations providing the contact angular extent and pressure distribution in terms of the applied load or jaw displacement, consequent to the progressive advance of the contact, are derived by using an inverse method. The obtained results are validated by comparison with previous theoretical and experimental results available in the literature. The study indicates that the method of dual series is simpler and more straightforward as compared to the analytical methods proposed in the literature for treating the Brazil disc test as an advancing contact problem.

S 308 and other X-ray emitting bubbles around Wolf–Rayet stars

Context. S 308 is an X-ray emitting bubble that surrounds the Wolf–Rayet star WR6. The structure shines in the optical as well and is thus known as the Dolphin Nebula. Due to its large angular extent, it has been covered at only 90% with past XMM-Newton observations. Aims. Thanks to the unique dataset provided by the all-sky survey performed in X-rays by SRG/eROSITA, we can show for the first time the image of the bubble in its entire extent in this band, together with its spectral characterization. Moreover, we have tried to apply the same procedure for other wind-blown bubbles detected in the optical/IR and we searched for X-ray extended emission around them. Methods. We first analyzed the diffuse emission of S308, providing a detailed spectral analysis. We then considered a sample of 22 optical/IR selected wind-blown bubbles from a previous study based on WISE data, providing an estimate of the X-ray flux for the first time. Results. We obtained the best fit for S308 with a two-temperature non-equilibrium plasma model (kT1 = 0.8-0.3+0.8 keV and kT2 = 2-1+3 keV) showing super-solar N abundance and low absorption. We did not detect any of the 22 optical/IR emitting bubbles in X-rays, but using our best fit model, we estimated the 3σ flux upper limits for each bubble. Conclusions. We demonstrate the new possibility offered by SRG/eROSITA to study known wind-blown bubbles and look for other ones. A two-temperature plasma description seems to fit the data quite well for S308. Since all of the 22 bubbles studied still remain undetected by SRG/eROSITA, it is very likely that absorption effects and spatial compactness are responsible for the challenges standing in the way of detecting these bubbles in soft X-rays.

Radio galaxy zoo: towards building the first multipurpose foundation model for radio astronomy with self-supervised learning

Abstract In this work, we apply self-supervised learning with instance differentiation to learn a robust, multipurpose representation for image analysis of resolved extragalactic continuum images. We train a multi-use model which compresses our unlabelled data into a structured, low dimensional representation which can be used for a variety of downstream tasks (e.g. classification, similarity search). We exceed baseline supervised Fanaroff–Riley classification performance by a statistically significant margin, with our model reducing the test set error by up to half. Our model is also able to maintain high classification accuracy with very few labels, with only $7.79{{\ \rm per\ cent}}$ error when only using 145 labels. We further demonstrate that by using our foundation model, users can efficiently trade off compute, human labelling cost and test set accuracy according to their respective budgets, allowing for efficient classification in a wide variety of scenarios. We highlight the generalizability of our model by showing that it enables accurate classification in a label scarce regime with data from the new MIGHTEE survey without any hyperparameter tuning, where it improves upon the baseline by $\sim 8{{\ \rm per\ cent}}$. Visualizations of our labelled and un-labelled data show that our model’s representation space is structured with respect to physical properties of the sources, such as angular source extent. We show that the learned representation is scientifically useful even if no labels are available by performing a similarity search, finding hybrid sources in the RGZ DR1 data set without any labels. We show that good augmentation design and hyperparameter choice can help achieve peak performance, while emphasizing that optimal hyperparameters are not required to obtain benefits from self-supervised pre-training.

A MUSE/VLT spatially resolved study of the emission structure of Green Pea galaxies

Green Pea galaxies (GPs) present among the most intense starbursts known in the nearby Universe. These galaxies are regarded as local analogs of high-redshift galaxies, making them a benchmark in the understanding of the star formation processes and the galactic evolution in the early Universe. In this work, we performed an integral field spectroscopic (IFS) study for a set of 24 GPs to investigate the interplay between its ionized interstellar medium (ISM) and the massive star formation that these galaxies present. Observations were taken in the optical spectral range (λ4750 Å–λ9350 Å) with the MUSE spectrograph attached to the 8.2 m telescope VLT. Spatial extension criteria were employed to verify which GPs are spatially resolved in the MUSE data cubes. We created and analyzed maps of spatially distributed emission lines (at different stages of excitation), continuum emission, and properties of the ionized ISM (e.g., ionization structure indicators, physical-chemical conditions, dust extinction). We also took advantage of our IFS data to produce integrated spectra of selected galactic regions in order to study their physical-chemical conditions. Maps of relevant emission lines and emission line ratios show that higher-excitation gas is preferentially located in the center of the galaxy, where the starburst is present. The continuum maps, with an average angular extent of 4″, exhibit more complex structures than the emission line maps. However, the [O III]λ5007 Å emission line maps tend to extend beyond the continuum images (the average angular extent is 5.5″), indicating the presence of low surface brightness ionized gas in the outer parts of the galaxies. Hα/Hβ, [S II]/Hα, and [O I]/Hα maps trace low-extinction, optically thin regions. The line ratios [O III]/Hβ and [N II]/Hα span extensive ranges, with values varying from 0.5 dex to 0.9 dex and from −1.7 dex to −0.8 dex, respectively. Regarding the integrated spectra, the line ratios were fit to derive physical properties including the electron densities ne = 30 − 530 cm−3, and, in six GPs with a measurable [O III]λ4363 Å line, electron temperatures of Te = 11 500 K–15 500 K, so the direct method was applied in these objects to retrieve metallicities 12 + log(O/H)≃8. We found the presence of the high-ionizing nebular He IIλ4686 Å line in three GPs, where two of them present among the highest sSFR values (> 8 × 108 yr−1) in this sample. Non-Wolf-Rayet (WR) features are detected in these galaxy spectra.

Investigating the IBEX Ribbon Structure a Solar Cycle Apart

A “Ribbon” of enhanced energetic neutral atom (ENA) emissions was discovered by the Interstellar Boundary Explorer in 2009, redefining our understanding of the heliosphere boundaries and the physical processes occurring at the interstellar interface. The Ribbon signal is intertwined with that of a globally distributed flux (GDF) that spans the entire sky. To a certain extent, Ribbon separation methods enabled examining its evolution independent of the underlying GDF. Observations over a full solar cycle revealed the Ribbon’s evolving nature, with intensity variations closely tracking those of the solar wind (SW) structure after a few years delay, accounting for the SW–ENA recycling process. In this work, we examine the Ribbon structure, namely its ENA fluxes, angular extent, width, and circularity properties for two years, 2009 and 2019, representative of the declining phases of two adjacent solar cycles. We find that, (i) the Ribbon ENA fluxes have recovered in the nose direction and south of it down to ∼25° (for energies below 1.7 keV) and not at mid and high ecliptic latitudes; (ii) the Ribbon width exhibits significant variability as a function of azimuthal angle; (iii) circularity analysis suggests that the 2019 Ribbon exhibits a statistically consistent radius with that in 2009. The Ribbon’s partial recovery is aligned with the consensus of a heliosphere with its closest point being southward of the nose region. The large variability of the Ribbon width as a function of azimuth in 2019 compared to 2009 is likely indicative of small-scale processes within the Ribbon.

A CO funnel in the Galactic centre: Molecular counterpart of the northern Galactic chimney

We report the discovery of a velocity coherent, funnel-shaped 13CO emission feature in the Galactic centre (GC) using data from the SEDIGISM survey. The molecular cloud appears as a low-velocity structure (VLSR = [ − 3.5, + 3.5] km s−1) with an angular extent of 0.95° ×1°, extending towards positive Galactic latitudes. The structure is offset from Sgr A* towards negative Galactic longitudes; it spatially and morphologically correlates well with the northern lobe of the 430 pc radio bubble, believed to be the radio counterpart of the multiwavelength GC chimney. Spectral line observations in the frequency range of 85–116 GHz have been carried out using the IRAM 30-m telescope towards 12 positions along the funnel-shaped emission. We examine the 12C/13C isotopic ratios using various molecules and their isotopologues. The mean 12C/13C isotope ratio (30.6 ± 2.9) is consistent with the structure located within inner 3 kpc of the Galaxy and possibly in the GC. The velocity of the molecular funnel is consistent with previous radio recombination line measurements of the northern lobe of radio bubble. Our multiwavelength analysis suggests that the funnel-shaped structure extending over 100 pc above the Galactic plane is the molecular counterpart of the northern GC chimney.

Analytical tool assisting the designer of pin-lug connections

A theoretical model of a pin-lug fitting in the presence of a pin-lug gap is developed that accounts for the nonlinear link between the load and the pin-lug angular width in this progressive contact, which is assumed frictionless. This model adopts a simplified lug geometry, described by a purely flexural partial ring whose extremities are fixed to a base, solved with the virtual work principle. Based on an already available load factor regrouping the effect on the contact angular extent of the applied load, of the Young’s modulus, and of the gap, but not of the lug geometry, an enhanced load factor is developed that includes, although approximately, the influence of the lug geometry on the contact angle. This approach is useful in selecting a suitable clearance between the lug and the pin, which keeps the contact pressure to a minimum for an imposed load.

Wavefront Sensing by a Common-Path Interferometer for Wavefront Correction in Phase and Amplitude by a Liquid Crystal Spatial Light Modulator Aiming the Exoplanet Direct Imaging

We implemented the common-path achromatic interfero-coronagraph both for the wavefront sensing and the on-axis image component suppression, aiming for the stellar coronagraphy. A common-path achromatic interfero-coronagraph has its optical scheme based on a nulling rotational-shear interferometer. The angle of rotational shear can be chosen at a small angular extent of about 10 deg. Such a small angular shear maintains the coronagraphic contrast degradation known as the stellar leakage effect, caused by a finite stellar size. We study the phase and amplitude wavefront control by a liquid crystal spatial light modulator of reflection type which is used as the pixilated active adaptive optics unit. Therefore, adaptive optics perform a wavefront-correcting input toward a stellar interfero-coronagraph aiming at the direct exoplanet imaging. Presented here are both the numeric evaluations and the lab experiment stand to prove the declared functionality output.

Enabling discovery of gravitationally lensed explosive transients: a new method to build an all-sky watch list of groups and clusters of galaxies

ABSTRACT Cross-referencing a watch list of galaxy groups and clusters with transient detections from real-time streams of wide-field survey data is a promising method for discovering gravitationally lensed explosive transients, including supernovae, kilonovae, gravitational waves, and gamma-ray bursts in the next 10 yr. However, currently there exists no catalogue of objects with both sufficient angular extent and depth to adequately perform such a search. In this study, we develop a cluster-finding method capable of creating an all-sky list of galaxy group- and cluster-scale objects out to z ≃ 1 based on their lens-plane properties and using only existing data from wide-field infrared surveys such as VISTA Hemisphere Survey and UKIRT Hemisphere Survey, and all-sky WISE (Wide-field Infrared Survey Explorer) data. In testing this method, we recover 91 per cent of a sample containing known and candidate lensing objects with Einstein radii of θE ≥ 5 arcsec. We also search the surrounding regions of this test sample for other groups and clusters using our method and verify the existence of any significant findings by visual inspection, deriving estimates of the false positive rate that are as low as 6 per cent. The method is also tested on simulated Rubin data from their Data Preview 0 programme, which yields complementary results of a good recovery rate of ≳80 per cent for M200 ≥ 7 × 1013 M⊙ clusters and with no false positives produced in our test region. Importantly, our method is positioned to create a watch list in advance of Rubin’s LSST, as it utilizes only existing data, therefore enabling the discovery of lensed transients early within the survey’s lifetime.

Programmable freeform optics with extended white light sources: possibilities and limitations.

Freeform optics can be used in lighting applications to generate accurate prescribed illumination patterns from compact light sources such as LEDs. When targeting dynamic illumination systems, a time-variable optical functionality is needed. Phase-only spatial light modulators (SLMs) have been used in the past for various dynamic beam shaping applications with monochromatic, zero-étendue illumination under paraxial conditions. Such limitations can no longer hold when considering lighting applications. In this paper, a novel algorithm for the calculation of smooth phase shift patterns is presented in order to generate arbitrary target patterns from arbitrary incident wave fronts for non-paraxial conditions. When applying such phase shift patterns to SLMs, these devices can be considered as programmable freeform optics. The experimental performance of the calculated phase patterns is analyzed on a real SLM, with a maximal phase shift of 6π, for collimated laser beams and white LEDs. The possibilities and limitations of generating accurate prescribed target patterns are critically discussed in terms of the angular extent of the target pattern, the consider spectrum of the light source and the étendue of the incident light beam.

Broadband study and the discovery of pulsations from the Be/X-ray binary eRASSU J052914.9−662446 in the Large Magellanic Cloud

Context.The Magellanic Clouds are our nearest star-forming galaxies. While the population of high-mass X-ray binaries (HMXBs) in the Small Magellanic Cloud is relatively well studied, our knowledge about the Large Magellanic Cloud (LMC) is far from complete given its large angular extent and the insufficient coverage with X-ray observations.Aims.We conducted a search for new HMXBs in the LMC using data from eROSITA, the soft X-ray instrument on board the Spektrum-Roentgen-Gamma satellite.Methods.After confirming the nature of eRASSU J052914.9−662446 as a hard X-ray source that is positionally coincident with an early-type star, we followed it up with optical spectroscopic observations from the South African Large Telescope (SALT) and a dedicatedNuSTARobservation.Results.We study the broadband timing and spectral behaviour of the newly discovered HMXB eRASSU J052914.9−662446 through eROSITA,Swift, andNuSTARdata in X-rays and the Optical Gravitational Lensing Experiment (OGLE) and SALT RSS data at the optical wavelength. We report the detection of a spin period at 1412 s and suggest that the orbital period of the system is ∼151 days. We thereby establish that eRASSU J052914.9−662446 is an accreting pulsar. Furthermore, through optical spectroscopic observations and the detection of Hαemission, the source is identified as a Be X-ray binary pulsar in the LMC. We also investigated the variability of the source in the optical and X-ray regime over the past decades and provide estimates of the possible magnetic field strength of the neutron star.