Wavefront sensing and control are important for enabling one of the key advantages of using large apertures, namely higher angular resolution. Pyramid wavefront sensors are becoming commonplace in ...new instrument designs owing to their superior sensitivity. However, one remaining roadblock to their widespread use is the fabrication of the pyramidal optic. This complex optic is challenging to fabricate due to the pyramid tip, where four planes need to intersect at a single point. Thus far, only a handful of these have been produced due to the low yields and long lead times. To address this, we present an alternative implementation of the pyramid wavefront sensor which relies instead on two roof prisms. Such prisms are easy and inexpensive to source. We demonstrate the successful operation of the roof prism pyramid wavefront sensor on an 8 m class telescope, at visible and near-infrared wavelengths, for the first time using a SAPHIRA HgCdTe detector without modulation for a laboratory demonstration, and elucidate how this sensor can be used more widely on wavefront control test benches and instruments.
Characterisation of exoplanets is key to understanding their formation, composition and potential for life. Nulling interferometry, combined with extreme adaptive optics, is among the most promising ...techniques to advance this goal. We present an integrated-optic nuller whose design is directly scalable to future science-ready interferometric nullers: the Guided-Light Interferometric Nulling Technology, deployed at the Subaru Telescope. It combines four beams and delivers spatial and spectral information. We demonstrate the capability of the instrument, achieving a null depth better than 10
with a precision of 10
for all baselines, in laboratory conditions with simulated seeing applied. On sky, the instrument delivered angular diameter measurements of stars that were 2.5 times smaller than the diffraction limit of the telescope. These successes pave the way for future design enhancements: scaling to more baselines, improved photonic component and handling low-order atmospheric aberration within the instrument, all of which will contribute to enhance sensitivity and precision.
We present L'-band imaging of the PDS 70 planetary system with Keck/NIRC2 using the new infrared pyramid wave front sensor. We detected both PDS 70 b and c in our images, as well as the front rim of ...the circumstellar disk. After subtracting off a model of the disk, we measured the astrometry and photometry of both planets. Placing priors based on the dynamics of the system, we estimated PDS 70 b to have a semimajor axis of au and PDS 70 c to have a semimajor axis of au (95% credible interval). We fit the spectral energy distribution (SED) of both planets. For PDS 70 b, we were able to place better constraints on the red half of its SED than previous studies and inferred the radius of the photosphere to be 2-3 RJup. The SED of PDS 70 c is less well constrained, with a range of total luminosities spanning an order of magnitude. With our inferred radii and luminosities, we used evolutionary models of accreting protoplanets to derive a mass of PDS 70 b between 2 and 4 MJup and a mean mass accretion rate between 3 × 10−7 and 8 × 10−7 MJup/yr. For PDS 70 c, we computed a mass between 1 and 3 MJup and mean mass accretion rate between 1 × 10−7 and 5 × 10−7 MJup/yr. The mass accretion rates imply dust accretion timescales short enough to hide strong molecular absorption features in both planets' SEDs.
It is common knowledge that nutritive stress resulting from decreased diversity and quality of food, pollution of food sources and beekeeping errors may lead to increased susceptibility of bees to ...pathogens and pesticides. The dearth of adequate food is frequently compensated with supplements. Thus, this research was aimed to study the effects of the plant-based supplement B + on colony strength (assessed according to open and sealed brood area, honey and pollen/bee bread reserves, and the number of adult bees). In addition, Nosema ceranae spores and viruses were quantified and the level of infestation with Varroa destructor assessed. The experiment was conducted in late summer and early spring. In colonies which were given B + in feed a significant increase (p < 0.05) in the parameters of colony strength were noticed in comparison to the control (colonies fed on sugar syrup). Moreover, it was proven that the bees from these colonies had significantly lower (p < 0.05) N. ceranae spore counts, and acute bee paralysis, deformed wing and sacbrood virus loads. Our results suggest that the addition of B + supplement to the colonies provide them with nutrients, contribute to their strengthening, might prevent nutritive stress and increase the success of bees in combating pathogens.
ABSTRACT
The characterization of exoplanets is critical to understanding planet diversity and formation, their atmospheric composition, and the potential for life. This endeavour is greatly enhanced ...when light from the planet can be spatially separated from that of the host star. One potential method is nulling interferometry, where the contaminating starlight is removed via destructive interference. The GLINT instrument is a photonic nulling interferometer with novel capabilities that has now been demonstrated in on-sky testing. The instrument fragments the telescope pupil into sub-apertures that are injected into waveguides within a single-mode photonic chip. Here, all requisite beam splitting, routing, and recombination are performed using integrated photonic components. We describe the design, construction, and laboratory testing of our GLINT pathfinder instrument. We then demonstrate the efficacy of this method on sky at the Subaru Telescope, achieving a null-depth precision on sky of ∼10−4 and successfully determining the angular diameter of stars (via their null-depth measurements) to milliarcsecond accuracy. A statistical method for analysing such data is described, along with an outline of the next steps required to deploy this technique for cutting-edge science.
Coherent Imaging with Photonic Lanterns Kim, Yoo Jung; Fitzgerald, Michael P.; Lin, Jonathan ...
The Astrophysical journal,
04/2024, Volume:
964, Issue:
2
Journal Article
Peer reviewed
Open access
Abstract Photonic lanterns (PLs) are tapered waveguides that gradually transition from a multimode fiber geometry to a bundle of single-mode fibers (SMFs). They can efficiently couple multimode ...telescope light into a multimode fiber entrance at the focal plane and convert it into multiple single-mode beams. Thus, each SMF samples its unique mode (lantern principal mode) of the telescope light in the pupil, analogous to subapertures in aperture masking interferometry (AMI). Coherent imaging with PLs can be enabled by the interference of SMF outputs and applying phase modulation, which can be achieved using a photonic chip beam combiner at the backend (e.g., the ABCD beam combiner). In this study, we investigate the potential of coherent imaging by the interference of SMF outputs of a PL with a single telescope. We demonstrate that the visibilities that can be measured from a PL are mutual intensities incident on the pupil weighted by the cross correlation of a pair of lantern modes. From numerically simulated lantern principal modes of a 6-port PL, we find that interferometric observables using a PL behave similarly to separated-aperture visibilities for simple models on small angular scales (< λ / D ) but with greater sensitivity to symmetries and capability to break phase angle degeneracies. Furthermore, we present simulated observations with wave front errors (WFEs) and compare them to AMI. Despite the redundancy caused by extended lantern principal modes, spatial filtering offers stability to WFEs. Our simulated observations suggest that PLs may offer significant benefits in the photon-noise-limited regime and in resolving small angular scales at the low-contrast regime.
With an almost global distribution,
Varroa destuctor
is the leading cause of weakening and loss of honey bee colonies. New substances are constantly being tested in order to find those that will ...exhibit high anti-
Varroa
efficacy at low doses/concentrations, without unwanted effects on bees. Lithium (Li) salts stood out as candidates based on previous research. The aims of this study were to evaluate Li citrate hydrate (Li-cit) for its contact efficacy against
Varroa
, but also the effect of Li-cit on honey bees by estimating loads of honey bee viruses, expression levels of immune-related genes and genes for antioxidative enzymes and oxidative stress parameters on two sampling occasions, before the treatment and after the treatment. Our experiment was performed on four groups, each consisting of seven colonies. Two groups were treated with the test compound, one receiving 5 mM and the other 10 mM of Li-cit; the third received oxalic acid treatment (OA group) and served as positive control, and the fourth was negative control (C group), treated with 50% w/v pure sucrose-water syrup. Single trickling treatment was applied in all groups. Both tested concentrations of Li-cit, 5 and 10 mM, expressed high varroacidal efficacy, 96.85% and 96.80%, respectively. Load of Chronic Bee Paralysis Virus significantly decreased (
p
< 0.01) after the treatment in group treated with 5 mM of Li-cit. In OA group, loads of Acute Bee Paralysis Virus and Deformed Wing Virus significantly (
p
< 0.05) increased, and in C group, loads of all viruses significantly (
p
< 0.01 or
p
< 0.001) increased. Transcript levels of genes for abaecin, apidaecin, defensin and vitellogenin were significantly higher (
p
< 0.05—
p
< 0.001), while all oxidative stress parameters were significantly lower (
p
< 0.05—
p
< 0.001) after the treatment in both groups treated with Li-cit. All presented results along with easy application indicate benefits of topical Li-cit treatment and complete the mosaic of evidence on the advantages of this salt in the control of
Varroa
.
Direct imaging of gas giant exoplanets provides information on their atmospheres and the architectures of planetary systems. However, few planets have been detected in blind surveys with direct ...imaging. Using astrometry from the Gaia and Hipparcos spacecraft, we identified dynamical evidence for a gas giant planet around the nearby star HIP 99770. We confirmed the detection of this planet with direct imaging using the Subaru Coronagraphic Extreme Adaptive Optics instrument. The planet, HIP 99770 b, orbits 17 astronomical units from its host star, receiving an amount of light similar to that reaching Jupiter. Its dynamical mass is 13.9 to 16.1 Jupiter masses. The planet-to-star mass ratio (7 to 8) × 10
is similar to that of other directly imaged planets. The planet's atmospheric spectrum indicates an older, less cloudy analog of the previously imaged exoplanets around HR 8799.
Photometric and astrometric calibration of high-contrast images is essential for the characterization of companions at small angular separation from their stellar host. The main challenge to ...performing accurate relative photometry and astrometry of high-contrast companions with respect to the host star is that the central starlight cannot be directly used as a reference, as it is either blocked by a coronagraphic mask or saturating the detector. Our approach is to add fiducial incoherent faint copies of the host star in the image plane and alternate the pattern of these copies between exposures. Subtracting two frames with different calibration patterns removes measurement bias due to static and slowly varying incoherent speckle halo components, while ensuring that calibration references are inserted on each frame. Each calibration pattern is achieved by high-speed modulation of a pupil-plane deformable mirror to ensure incoherence. We implemented the technique on-sky on the Subaru Coronagraphic Extreme Adaptive Optics instrument with speckles which were of the order of 103 times fainter than the central host. The achieved relative photometric and astrometric measurement precisions for 10 s exposure were respectively 5% and 20 milliarcsecond. We also demonstrate, over a 540 s measurement span, that residual photometric and astrometric errors are uncorrelated in time, indicating that residual noise averages as the inverse square root of the number of exposures in longer time-series data sets.
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