Instrument Throughput Research Articles

Commissioning of the MIRAC-5 Mid-infrared Instrument on the MMT

Abstract We present results from commissioning observations of the mid-IR instrument, MIRAC-5, on the 6.5 m MMT telescope. MIRAC-5 is a novel ground-based instrument that utilizes a state-of-the-art GeoSnap (2–13 µm) HgCdTe detector with adaptive optics support from MAPS to study protoplanetary disks, wide-orbit brown dwarfs, planetary companions in the contrast-limit, and a wide range of other astrophysical objects. We have used MIRAC-5 on six engineering observing runs, improving its performance and defining operating procedures. We characterize key aspects of MIRAC-5's performance, including verification that the total telescope, atmosphere, instrument, and detector throughput is approximately 10%. Following a planned dichroic upgrade, the system will have a throughput of 20% and background limiting magnitudes (for SNR = 5 and 8 hr exposure times) of 18.0, 15.6, and 12.6 for the L’, M’, and N’ filters, respectively. The detector pixels experience 1/f noise but, if the astrophysical scene is properly modulated via chopping and nodding sequences, it is less than 10% the Poisson noise from the observed background in an 85 Hz frame. We achieve close to diffraction-limited performance in the N-band and all bands are expected to reach diffraction-limited performance following the adaptive optics system commissioning. We also present an exposure time calculator calibrated to the on-sky results. In its current state, MIRAC-5 will be capable of achieving several scientific objectives including the observation of warm wide-orbit companions. Once the adaptive optics is commissioned and a coronagraph installed in 2025, MIRAC-5 will have contrast-limited performance comparable to JWST, opening new and complementary science investigations for close-in companions.

Detectability of biosignatures in warm, water-rich atmospheres

Context. Warm rocky exoplanets within the habitable zone of Sun-like stars are favoured targets for current and future missions. Theory indicates these planets could be wet at formation and remain habitable long enough for life to develop. However, it is unclear to what extent an early ocean on such worlds could influence the response of potential biosignatures. Aims. In this work we test the climate-chemistry response, maintenance, and detectability of biosignatures in warm, water-rich atmospheres with Earth biomass fluxes within the framework of the planned LIFE mission. Methods. We used the coupled climate-chemistry column model 1D-TERRA to simulate the composition of planetary atmospheres at different distances from the Sun, assuming Earth’s planetary parameters and evolution. We increased the incoming instellation by up to 50% in steps of 10%, corresponding to orbits of 1.00 to 0.82 AU. Simulations were performed with and without modern Earth’s biomass fluxes at the surface. Theoretical emission spectra of all simulations were produced using the GARLIC radiative transfer model. LIFEsim was then used to add noise to and simulate observations of these spectra to assess how biotic and abiotic atmospheres of Earth-like planets can be distinguished. Results. Increasing instellation leads to surface water vapour pressures rising from 0.01 bar (1.31%, S = 1.0) to 0.61 bar (34.72%, S = 1.5). In the biotic scenarios, the ozone layer survives because hydrogen oxide reactions with nitrogen oxides prevent the net ozone chemical sink from increasing. Methane is strongly reduced for instellations that are 20% higher than that of the Earth due to the increased hydrogen oxide abundances and UV fluxes. Synthetic observations with LIFEsim, assuming a 2.0 m aperture and resolving power of a R = 50, show that ozone signatures at 9.6 µm reliably point to Earth-like biosphere surface fluxes of O2 only for systems within 10 parsecs. The differences in atmospheric temperature structures due to differing H2O profiles also enable observations at 15.0 µm to reliably identify planets with a CH4 surface flux equal to that of Earth’s biosphere. Increasing the aperture to 3.5 m and increasing instrument throughput to 15% increases this range to 22.5 pc.

Large Interferometer For Exoplanets (LIFE)

Context.A mid-infrared nulling-space interferometer offers a promising way to characterize thermal light from habitable planet candidates around Sun-like stars. However, one of the main challenges inherent in achieving this ambitious goal is the high-precision stability of the optical path difference and amplitude over a few days for planet detections and all the way up to a few weeks for in-depth characterization. This is related to mission parameters such as aperture size, number of apertures, and total instrument throughput.Aims.Here, we propose a new method called phase-space synthesis decomposition (PSSD) to shorten the stability requirement to a scale of minutes, significantly relaxing the technological challenges of the mission.Methods.By focusing on the consideration of what exactly modulates the planetary signal in the presence of the stellar leak and systematic error, PSSD prioritizes the modulation of the signals along the wavelength domain rather than baseline rotation. Modulation along the wavelength domain allows us to extract source positions in parallel to the baseline vector for each exposure. The sum of the one-dimensional data is converted into two-dimensional information. Based on the reconstructed image, we constructed a continuous equation and extract the spectra through the singular value decomposition, while efficiently separating them from a long-term systematic stellar leak.Results.We performed numerical simulations to investigate the feasibility of PSSD for the Large Interferometer For Exoplanets (LIFE) mission concept. We confirm that multiple terrestrial planets in the habitable zone around a Sun-like star at 10 pc can be detected and characterized despite high levels and long durations of systematic noise. We also find that PSSD is more robust against a sparse sampling of the array rotation compared to purely rotation-based signal extraction. Using PSSD as signal extraction method significantly relaxes the technical requirements on the signal stability and further increases the feasibility of the LIFE mission.

Upgrades to W. M. Keck observatory detector systems

We report on our plans to upgrade the detector systems in the 2022–2024 time frame for three of the workhorse instruments (NIRC2, DEIMOS, and NIRES) operated by the W. M. Keck Observatory. The upgrades are done in collaboration with Observatory partner institutions and other Maunakea observatories. The main motivating factors behind these upgrades are to tackle obsolescence of hardware and software components, to boost observing efficiency, to enhance the instrument throughput, and to add new observing functionality.

Large Interferometer For Exoplanets (LIFE)

Context. Identifying and characterizing habitable and potentially inhabited worlds is one of the main goals of future exoplanet direct-imaging missions. The number of planets within the habitable zone (HZ) that are accessible to such missions is a key metric to quantify their scientific potential, and it can drive the mission and instrument design. Aims. While previous studies have shown a strong preference for a future mid-infrared nulling interferometer space mission, such as LIFE, to detect planets within the HZ around M dwarfs, we here focus on a more conservative approach toward the concept of habitability and present yield estimates for two stellar samples consisting of nearby (d < 20 pc) Sun-like stars (4800 K ≤ Teff ≤ 6300 K) and nearby FGK-type stars (3940 K ≤ Teff ≤ 7220 K) accessible to such a mission. Methods. Our yield estimates are based on recently derived occurrence rates of rocky planets from the Kepler mission and our LIFE exoplanet observation simulation tool LIFEsim, which includes all main astrophysical noise sources, but no instrumental noise sources as yet. In a Monte Carlo-like approach, we marginalized over 1000 synthetic planet populations simulated around single and wide binary stars from our two samples. We use new occurrence rates for rocky planets that cover the entire HZ around FGK-type stars, marginalize over the uncertainties in the underlying occurrence rate model, present a parameter study investigating the dependence of the planet yield on different instrumental and astrophysical parameters, and estimate the number of detectable HZ planets that might indeed harbor liquid surface water. Results. Depending on a pessimistic or optimistic extrapolation of the Kepler results, we find that during a 2.5-yr search phase, LIFE could detect between ~10–16 (average) or ~5–34 (including 1σ uncertainties) rocky planets (0.5 R⊕ ≤ Rp ≤ 1.5 R⊕) within the optimistic HZ of Sun-like stars and between ~4–6 (average) or ~1–13 (including 1σ uncertainties) exo-Earth candidates (EECs) assuming four collector spacecraft equipped with 2 m mirrors and a conservative instrument throughput of 5%. The error bars are dominated by uncertainties in the underlying planet occurrence rates and the extrapolation of the Kepler results. With D = 3.5 m or 1 m mirrors, the yield Y changes strongly, following approximately Y ∝ D3/2. With the larger sample of FGK-type stars, the yield increases to ~ 16–22 (average) rocky planets within the optimistic HZ and ~5–8 (average) EECs, which corresponds to ~50% of the yield predicted for M dwarfs in LIFE paper I. Furthermore, we find that in addition to the mirror diameter, the yield depends strongly on the total throughput, but only weakly on the exozodiacal dust level and the accessible wavelength range of the mission. Conclusions. When the focus lies entirely on Sun-like stars, larger mirrors (~3 m with 5% total throughput) or a better total throughput (~20% with 2 m mirrors) are required to detect a statistically relevant sample of ~30 rocky planets within the optimistic HZ. When the scope is extended to FGK-type stars, and especially when M dwarfs are included, a significant increase in the number of detectable rocky HZ planets is obtained, which relaxes the requirements on mirror size and total throughput. Observational insight into the habitability of planets orbiting M dwarfs, for example, from the James Webb Space Telescope, is crucial for guiding the target selection and observing sequence optimization for a mission such as LIFE.

A modified LC-MS/MS method for the detection of whole blood tacrolimus and its clinical value in Chinese kidney transplant patients

BackgroundFor patients who treated with tacrolimus after kidney transplant, therapeutic drug monitoring is essential to improve their prognosis. However, previous detection methods have limitations, such as the overestimation and unacceptable bias in the immunoassays. Precision medicine has been challenged. The liquid chromatography-tandem mass spectrometry (LC-MS/MS) method is recognized as the gold standard due to its accuracy and specificity, but lack of throughput and complex process limits its clinical application. Therefore, an accurate, simple and high throughput method for tacrolimus monitoring is needed for clinical practice. MethodsA modified LC-MS/MS method was introduced and validated. Whole blood samples were prepared by a one-step protein precipitation method. Chromatographic separation was achieved using a Phenomenex Kinetex 2.6 μm XB-C18 2.1 × 50 mm column with a total run time of 3.5 min to avoid matrix effect. An electrospray ionization source (ESI) was used in positive ion multiple reaction monitoring (MRM) mode for mass spectrometric detection. In order to protect the mass spectrometer, only part of the sample after LC separation was allowed to enter the mass spectrum, through a two HPLC systems coupled one mass spectrometry design. In this way, the instrument throughput is also improved and realizing the detection of 2 samples within 3.5 min and carried out a shorter analyzing time for each sample of 1.75 min. Additionally, we calculated tacrolimus-intrapatient variant (Tac-IPV) based on this modified method and assessed the prognostic value of Tac-IPV in Chinese kidney transplant patients. ResultsThe LC-MS/MS was modified by streamlining the procedure and increasing the throughput. The method proved to be accurate and reproducible with all performance parameters suitably meeting the clinical requirements over a calibration ranged from 0.37 to 42.90 ng/mL. Parameters such as linearity, limit of quantification (LoQ) and dilution integrity were validated with a clinical reportable range from 0.37 to 343.20 ng/mL, which was particularly useful for high drug concentrations patients (rare but very serious). Both cross-contamination and matrix effects were negligible. Clinical data of 83 patients showed that Tac-IPV was associated with poor kidney transplant outcome in Chinese (Hazard Ratio (HR) = 3.96, 4.75; 95% Cl: 1.10–14.21, 1.23–18.36; P < 0.05). ConclusionsThis modified LC-MS/MS method possessed high throughput and simple sample preparation, allowing it to meet daily clinical needs. At the same time, Tac-IPV based on this modified LC-MS/MS had excellent prognostic value in kidney transplantation. These advantages have great significance for the individualized treatment of Chinese kidney transplant patients and broad application of Tac-IPV.

Large Interferometer For Exoplanets (LIFE)

Context.Temperate terrestrial exoplanets are likely to be common objects, but their discovery and characterization is very challenging because of the small intrinsic signal compared to that of their host star. Various concepts for optimized space missions to overcome these challenges are currently being studied. The Large Interferometer For Exoplanets (LIFE) initiative focuses on the development of a spacebased mid-infrared (MIR) nulling interferometer probing the thermal emission of a large sample of exoplanets.Aims.This study derives the minimum requirements for the signal-to-noise ratio (S/N), the spectral resolution (R), and the wavelength coverage for the LIFE mission concept. Using an Earth-twin exoplanet as a reference case, we quantify how well planetary and atmospheric properties can be derived from its MIR thermal emission spectrum as a function of the wavelength range,S/N,andR.Methods.We combined a cloud-free 1D atmospheric radiative transfer model, a noise model for observations with the LIFE interferometer, and the nested sampling algorithm for Bayesian parameter inference to retrieve planetary and atmospheric properties. We simulated observations of an Earth-twin exoplanet orbiting a G2V star at 10 pc from the Sun with different levels of exozodiacal dust emissions. We investigated a grid of wavelength ranges (3–20 μm, 4–18.5 μm, and 6–17 μm),S/Ns(5, 10, 15, and 20 determined at a wavelength of 11.2 μm), andRs (20, 35, 50, and 100).Results.We find that H2O, CO2, and O3are detectable ifS/N ≥10 (uncertainty ≤ ± 1.0 dex). We find upper limits for N2O (abundance ≲10−3). In conrtrast, CO, N2, and O2are unconstrained. The lower limits for a CH4detection areR= 50 andS/N= 10. Our retrieval framework correctly determines the exoplanet’s radius (uncertainty ≤ ± 10%), surface temperature (uncertainty ≤ ± 20 K), and surface pressure (uncertainty ≤ ± 0.5 dex) in all cloud-free retrieval analyses. Based on our current assumptions, the observation time required to reach the specifiedS/Nfor an Earth-twin at 10 pc when conservatively assuming a total instrument throughput of 5% amounts to ≈6−7 weeks with four 2m apertures.Conclusions.We provide first order estimates for the minimum technical requirements for LIFE via the retrieval study of an Earth-twin exoplanet. We conclude that a minimum wavelength coverage of 4–18.5 μm, anRof 50, and anS/Nof at least 10 is required. With the current assumptions, the atmospheric characterization of several Earth-like exoplanets at a distance of 10 pc and within a reasonable amount of observing time will require apertures ≥ 2m.

Large Interferometer For Exoplanets (LIFE)

Context.One of the long-term goals of exoplanet science is the atmospheric characterization of dozens of small exoplanets in order to understand their diversity and search for habitable worlds and potential biosignatures. Achieving this goal requires a space mission of sufficient scale that can spatially separate the signals from exoplanets and their host stars and thus directly scrutinize the exoplanets and their atmospheres.Aims.We seek to quantify the exoplanet detection performance of a space-based mid-infrared (MIR) nulling interferometer that measures the thermal emission of exoplanets. We study the impact of various parameters and compare the performance with that of large single-aperture mission concepts that detect exoplanets in reflected light.Methods.We have developed an instrument simulator that considers all major astrophysical noise sources and coupled it with Monte Carlo simulations of a synthetic exoplanet population around main-sequence stars within 20 pc of the Sun. This allows us to quantify the number (and types) of exoplanets that our mission concept could detect. Considering single visits only, we discuss two different scenarios for distributing 2.5 yr of an initial search phase among the stellar targets. Different apertures sizes and wavelength ranges are investigated.Results.An interferometer consisting of four 2 m apertures working in the 4–18.5 μ.m wavelength range with a total instrument throughput of 5% could detect up to ≈550 exoplanets with radii between 0.5 and 6R⊕with an integratedS/N≥ 7. At least ≈160 of the detected exoplanets have radii ≤1.5R⊕. Depending on the observing scenario, ≈25–45 rocky exoplanets (objects with radii between 0.5 and 1.5R⊕) orbiting within the empirical habitable zone (eHZ) of their host stars are among the detections. With four 3.5 m apertures, the total number of detections can increase to up to ≈770, including ≈60–80 rocky eHZ planets. With four times 1 m apertures, the maximum detection yield is ≈315 exoplanets, including ≤20 rocky eHZ planets. The vast majority of small, temperate exoplanets are detected around M dwarfs. The impact of changing the wavelength range to 3–20 μm or 6–17 μm on the detection yield is negligible.Conclusions.A large space-based MIR nulling interferometer will be able to directly detect hundreds of small, nearby exoplanets, tens of which would be habitable world candidates. This shows that such a mission can compete with large single-aperture reflected light missions. Further increasing the number of habitable world candidates, in particular around solar-type stars, appears possible via the implementation of a multi-visit strategy during the search phase. The high median S/N of most of the detected planets will allow for first estimates of their radii and effective temperatures and will help prioritize the targets for a second mission phase to obtain high-S/N thermal emission spectra, leveraging the superior diagnostic power of the MIR regime compared to shorter wavelengths.

Combined spectroscopy and intensity interferometry to determine the distances of the blue supergiants P Cygni and Rigel

ABSTRACT In this paper, we report on spatial intensity interferometry measurements within the Hα line on two stars: the Luminous Blue Variable supergiant P Cygni and the late-type B supergiant Rigel. The experimental setup was upgraded to allow simultaneous measurement of two polarization channels, instead of one in our previous setup, and the zero baseline correlation function on-sky to validate independent estimates obtained from the stellar spectrum and the instrumental spectral throughput. Combined with simultaneous spectra measurements and based on radiative transfer models calculated with the code CMFGEN, we were able to fit our measured visibility curves to extract the stellar distances. Our distance determinations for both P Cygni (1.61 ± 0.18 kpc) and Rigel (0.26 ± 0.02 kpc) agree very well with the values provided by astrometry with the Gaia and Hipparcos missions, respectively. This result for Rigel was obtained by adopting a stellar luminosity of L⋆ = 123 000 L⊙, which is reported in the literature as being consistent with the Hipparcos distance to Rigel. However, due to the lack of consensus on Rigel’s luminosity, we also explore how the adoption of the stellar luminosity in our models affects our distance determination for Rigel. In conclusion, we support, in an independent way, the distance to Rigel as the one provided by the Hipparcos mission, when taking the luminosity of 123 000 L⊙ at face value. This study is the first successful step towards extending the application of the Wind Momentum Luminosity Relation method for distance calibration from an LBV supergiant to a more normal late-type B supergiant.

Highly Sensitive, Non-cryogenic NIR High-resolution Spectrograph, WINERED

WINERED is a novel near-infrared (NIR) high-resolution spectrograph (HRS) that pursues the highest possible sensitivity to realize high-precision spectroscopy in the NIR as in the optical wavelength range. WINERED covers 0.9–1.35 μm (z, Y, and J-bands) with three modes (Wide mode and two Hires modes) at the maximum spectral resolutions of R = 28,000 and R = 70,000. For fulfilling the objective, WINERED is designed with an unprecedentedly high instrument throughput (up to 50% at maximum including the quantum efficiency of the array) that is three times or more than other existing optical/NIR HRSs. This is mainly realized by a combination of non-white pupil and no fiber-fed configuration in optical design, the moderate (optimized) wavelength coverage, and the high-throughput gratings. Another prominent feature of WINERED is “warm” instrument despite for infrared (IR) observations. Such non-cryogenic (no cold stop) IR instrument finally became possible with the combination of custom-made thermal-cut filter of 10−8 class, 1.7 μm cutoff HAWAII-2RG array, and a cold baffle reducing the direct thermal radiation to the IR array into the solid angle of f/2. The thermal background is suppressed below 0.1 photons pixel−1 s−1 even in the wide band of 0.9–1.35 μm under the environment of 290 K. WINERED had been installed to the 3.58 m New Technology Telescope at La Silla Observatory, ESO, since 2017. Even with the intermediate size telescope, WINERED was confirmed to provide a limiting magnitude (for SNR = 30 with 8 hr. integration time) of J = 16.4 mag for the Wide mode and J = 15.1 mag for the Hires mode, respectively, under the natural seeing conditions. These sensitivities are comparable to those for the existing NIR-HRSs attached to the 8–10 m class telescopes with AO. WINERED type spectrographs may become a critical not only for the currently on-going extremely large telescopes to reduce the developing cost and time but also for smaller telescopes to extend their lives with long programs.

Multiplexed Ion Beam Imaging: Insights into Pathobiology.

Next-generation tools for multiplexed imaging have driven a new wave of innovation in understanding how single-cell function and tissue structure are interrelated. In previous work, we developed multiplexed ion beam imaging by time of flight, a highly multiplexed platform that uses secondary ion mass spectrometry to image dozens of antibodies tagged with metal reporters. As instrument throughput has increased, the breadth and depth of imaging data have increased as well. To extract meaningful information from these data, we have developed tools for cell identification, cell classification, and spatial analysis. In this review, we discuss these tools and provide examples of their application in various contexts, including ductal carcinoma in situ, tuberculosis, and Alzheimer's disease. We hope the synergy between multiplexed imaging and automated image analysis will drive a new era in anatomic pathology and personalized medicine wherein quantitative spatial signatures are used routinely for more accurate diagnosis, prognosis, and therapeutic selection.

Design considerations of photonic lanterns for diffraction-limited spectrometry

The coupling of large telescopes to astronomical instruments has historically been challenging due to the tension between instrument throughput and stability. Light from the telescope can either be injected wholesale into the instrument, maintaining high throughput at the cost of point-spread function (PSF) stability, or the time-varying components of the light can be filtered out with single-mode fibers (SMFs), maintaining instrument stability at the cost of light loss. Today, the field of astrophotonics provides a potential resolution to the throughput-stability tension in the form of the photonic lantern (PL): a tapered waveguide that can couple a time-varying and aberrated PSF into multiple diffraction-limited beams at an efficiency that greatly surpasses direct SMF injection. As a result, lantern-fed instruments retain the stability of SMF-fed instruments while increasing their throughput. To this end, we present a series of numerical simulations characterizing PL performance as a function of lantern geometry, wavelength, and wavefront error (WFE), aimed at guiding the design of future diffraction-limited spectrometers. These characterizations include a first look at the interaction between PLs and phase-induced amplitude apodization (PIAA) optics. We find that Gaussian-mapping beam-shaping optics can enhance coupling into 3-port lanterns but offer diminishing gains with larger lanterns. In the y and J band (0.97–1.35 µm) region, with moderately high WFE ( ∼ 10 % Strehl ratio), a 3-port lantern in conjunction with beam-shaping optics strikes a good balance between pixel count and throughput gains. If pixels are not a constraint, and the flux in each port will be dominated by photon noise, then larger port count lanterns will provide further coupling gains due to a greater resilience to tip-tilt errors. Finally, we show that lanterns can maintain high operating efficiencies over large wavelength bands where the number of guided modes at the lantern entrance drops, if care is taken to minimize the attenuation of weakly radiative input modes.

Microproteomic sample preparation.

Multiple applications of proteomics in life and health science, pathology and pharmacology, require handling size-limited cell and tissue samples. During proteomic sample preparation, analyte loss in these samples arises when standard procedures are used. Thus, specific considerations have to be taken into account for processing, that are summarised under the term microproteomics (μPs). Microproteomic workflows include: sampling (e.g., flow cytometry, laser capture microdissection), sample preparation (possible disruption of cells or tissue pieces via lysis, protein extraction, digestion in bottom-up approaches, and sample clean-up) and analysis (chromatographic or electrophoretic separation, mass spectrometric measurements and statistical/bioinformatic evaluation). All these steps must be optimised to reach wide protein dynamic ranges and high numbers of identifications. Under optimal conditions, sampling is adapted to the studied sample types and nature, sample preparation isolates and enriches the whole protein content, clean-up removes salts and other interferences such as detergents or chaotropes, and analysis identifies as many analytes as the instrumental throughput and sensitivity allow. In the suggested review, we present and discuss the current state in μP applications for processing of small number of cells (cell μPs) and microscopic tissue regions (tissue μPs).

COVID-19 Pandemic Planning: Simulation Models to Predict Biochemistry Test Capacity forPatient Surges.

BackgroundPatient surges beyond hospital capacity during the initial phase of the COVID-19 pandemic emphasized a need for clinical laboratories to prepare test processes to support future patient care. The objective of this study was to determine if current instrumentation in local hospital laboratories can accommodate the anticipated workload from COVID-19 infected patients in hospitals and a proposed field hospital in addition to testing for non-infected patients.MethodsSimulation models predicted instrument throughput and turn-around-time for chemistry, ion-selective-electrode and immunoassay tests using vendor-developed software with different workload scenarios. The expanded workload included tests from anticipated COVID patients in two local hospitals and a proposed field hospital with a COVID-specific test menu in addition to the pre-pandemic workload.ResultsInstrumentation throughput and turn-around time at each site was predicted. With additional COVID-patient beds in each hospital the maximum throughput was approached with no impact on turnaround time. Addition of the field hospital workload led to significantly increased test turnaround times at each site.ConclusionsSimulation models depicted the analytic capacity and turn-around times for laboratory tests at each site and identified the laboratory best suited for field hospital laboratory support during the pandemic.

Mirrors for Space Telescopes: Degradation Issues

Mirrors are a subset of optical components essential for the success of current and future space missions. Most of the telescopes for space programs ranging from earth observation to astrophysics and covering the whole electromagnetic spectrum from x-rays to far-infrared are based on reflective optics. Mirrors operate in diverse and harsh environments that range from low-earth orbit to interplanetary orbits and deep space. The operational life of space observatories spans from minutes (sounding rockets) to decades (large observatories), and the performance of the mirrors within the mission lifetime is susceptible to degrading, resulting in a drop in the instrument throughput, which in turn affects the scientific return. Therefore, the knowledge of potential degradation mechanisms, how they affect mirror performance, and how to prevent them is of paramount importance to ensure the long-term success of space telescopes. In this review, we report an overview of current mirror technology for space missions with a focus on the importance of the degradation and radiation resistance of coating materials. Special attention is given to degradation effects on mirrors for far and extreme UV, as in these ranges the degradation is enhanced by the strong absorption of most contaminants.

Tracing the 107 K warm–hot intergalactic medium with UV absorption lines

ABSTRACT Today, the majority of the cosmic baryons in the Universe are not observed directly, leading to an issue of ‘missing baryons’ at low redshift. Cosmological hydrodynamical simulations have indicated that a significant portion of them will be converted into the so-called warm–hot intergalactic medium (WHIM), with gas temperature ranging between 105 and 107 K. While the cooler phase of this gas has been observed using O vi and Ne viii absorbers at ultraviolet (UV) wavelengths, the hotter fraction detection relies mostly on observations of O vii and O viii at X-ray wavelengths. Here, we target the forbidden line of [Fe xxi] λ 1354 Å which traces 107 K gas at UV wavelengths, using more than 100 high-spectral resolution ($R\sim 49\, 000$) and high signal to noise VLT/UVES quasar spectra, corresponding to over 600 h of VLT time observations. A stack of these at the position of known Ly α absorbers lead to a 5σ limit of $\log [N\mathrm{([Fe\,{\small XXI}])]\lt }$17.4 (EWrest &amp;lt; 22 mÅ), three orders of magnitude higher than the expected column density of the WHIM $\log [N\mathrm{([Fe\,{\small XXI}])]\lt }$14.5. This work proposes an alternative to X-ray detected 107 K WHIM tracers, by targeting faint lines at UV wavelengths from the ground benefiting from higher instrumental throughput, enhanced spectral resolution, longer exposure times, and increased number of targets. The number of quasar spectra required to reach this theoretical column density with future facilities including 4MOST, ELT/HIRES, MSE, and the Spectroscopic Telescope appears challenging at present. Probing the missing baryons is essential to constrain the accretion and feedback processes that are fundamental to galaxy formation.

Next Generation Sequencing Technology in Clinical Diagnostics

The promise of next generation sequencing offers hope for the current DNA sequencing technology to evolve from the applications in basic research to transition to the clinical diagnostics. This advancement in the sequencing technology is happening in part due to the introduction of high throughput and benchtop instruments that offer fully automated cost-effective sequencing along with faster assay times. This development is believed to remove the bottleneck of the complex and cumbersome library preparation that include isolation of nucleic acids and the resulting amplified and barcoded DNA with sequencing adapters. Here, we present a brief overview of the principles of next generation sequencing and automation of library preparation along with the diagnostic applications of next generation sequencing in human immunogenetics. Finally, an outlook is presented.

Comparison of the Panther Fusion and a laboratory-developed test targeting the envelope gene for detection of SARS-CoV-2

BackgroundNumerous nucleic acid amplification assays have recently received emergency use authorization (EUA) for the diagnosis of SARS-CoV-2 infection, and there is a need to assess their test performance relative to one another. ObjectivesThe aim of this study was to compare the test performance of the Hologic Panther Fusion SARS-CoV-2 assay targeting two regions of open reading frame 1ab (ORF1ab) to a high complexity molecular-based, laboratory-developed EUA from Stanford Health Care (SHC) targeting the SARS-CoV-2 envelope (E) gene. Study designWe performed a diagnostic comparison study by testing nasopharyngeal samples on the two assays. Assay agreement was assessed by overall percent agreement and Cohen’s kappa coefficient. ResultsA total of 184 nasopharyngeal samples were tested using the two assays, of which 180 showed valid results and were included for the comparative analysis. Overall percent agreement between the assays was 98.3 % (95 % confidence interval (CI) 95.2–99.7) and kappa coefficient was 0.97 (95 % CI 0.93–1.0). One sample was detected on the SHC laboratory developed test (LDT) and not on the Panther Fusion, and had a Ct of 35.9. Conversely, 2 samples were detected on the Panther Fusion and not on the LDT, and had Ct values of 37.2 and 36.6. ConclusionThe Panther Fusion SARS-CoV-2 assay and the SHC LDT perform similarly on clinical nasopharyngeal swab specimens. Other considerations, including reagent availability, turnaround time, labor requirements, cost and instrument throughput should guide the decision of which assay to perform.

Synergies between space telescopes in the photometric characterization of the atmospheres of Hot Jupiters

Previous generation of instruments have the opportunity to discover thousands of extra-solar planets and more will come with the current and future planet-search missions. In order to go one step further in the characterization of exoplanets, in this paper we describe a way to compare the photometric observation of Hot Jupiters done with space telescopes such as HST, CHEOPS, TESS, PLATO, and JWST and give the first-hand characterization on their atmospheres. We analyze a set of planetary systems hosting a Hot Jupiter for which an atmospheric template is available in the literature. For each system, we simulate the transit light curves observed by different instruments, convolving the incoming spectrum with the corresponding instrumental throughput. For each instrument, we thus measure the expected transit depth and estimate the associated uncertainty. Finally, we compare the transit depths as seen by the selected instruments and we quantify the effect of the planetary atmosphere on multi-band transit photometry. We also analyze a set of simulated scenarios with different stellar magnitudes, activity levels, transit durations and atmospheric templates to find the best cases for this kind of observational approach. We find in general that current and especially future space telescopes provide enough photometric precision to detect significant differences between the transit depths at different wavelengths. In particular, we find that the chromatic effect due to the atmosphere of the Hot Jupiters is maximized at later spectral types and that the effect of stellar activity is smaller than the measurement uncertainties.

Testing the Detectability of Extraterrestrial O2 with the Extremely Large Telescopes Using Real Data with Real Noise

Abstract The future extremely large telescopes (ELTs) are expected to be powerful tools to probe the atmospheres of extrasolar planets using high-dispersion spectroscopy, with the potential to detect molecular oxygen in Earth-like planets transiting nearby late-type stars. So far, simulations have concentrated on the optical 7600 Å A-band of oxygen using synthetic noise distributions. In this Letter, we build upon previous work to predict the detectability of molecular oxygen in nearby, temperate planets by using archival, time-series data of Proxima Centauri from the high-dispersion Ultraviolet and Visual Echelle Spectrograph (UVES) on ESO’s Very Large Telescope (VLT). The brightest transiting M-dwarfs are expected to be about 25 times fainter than Proxima, a factor that is similar to the difference in light-gathering power between the VLT and the future ELTs. By injecting synthetic oxygen transmission signals into the UVES data, the detectability can be studied in the presence of real data with real noise properties. Correcting for the relatively low throughput (∼4%) of the Proxima spectra to an assumed 20% throughput for a high-dispersion spectrograph on the European ELT, we find that the molecular oxygen signature of an Earth-twin transiting a nearby (d ≈ 7 pc) M5V star can be detected in 20–50 transits (a total of 70–175 hr of observing time). This estimate, using more realistic simulations, is close to previous predictions. Novel concepts that increase the instrumental throughput can further reduce the time span over which such observations need to be taken.