Distant Sources Research Articles

Strong Gravitational Lensing of Gravitational Waves: A Review

The first successful detection of gravitational waves (GWs) opened up a new window to study a realm of the most violent phenomena in the universe, such as coalescences of binary black holes (BH–BH), binary neutron stars (NS–NS), and mixed (BH–NS) systems, which are mostly inaccessible in the electromagnetic window. On the other hand, strong gravitational lensing of distant sources, such as galaxies and quasars, by other massive objects lying closer along the line of sight has become a powerful tool in cosmology and astrophysics. With the increasing sensitivity of the new generation of GW detectors, the chances to detect a strongly lensed GW signal are increasing. When GWs are strongly lensed, magnification of the signal intensity is expected, unveiling binary compact objects otherwise too distant to be detected. Such systems are important for their plethora of applications. Lensed GWs can be a test for general relativity, constrain mass distribution in galaxies or galaxy clusters, and provide cosmography information independently of the local cosmic ladders. In this review, we will provide a theoretical background of the gravitational lensing of GWs, including the wave optics regime, which becomes important in this context. Then we will describe the possible cosmological and astrophysical insight hidden in these signals, and present the state-of-the-art searches of lensed GWs in the present and future GW observatories.

Astrometric VLBI observations of H2O masers in an extreme OH/IR star candidate NSV 17351

Abstract The results of astrometric very long baseline interferometry (VLBI) observations toward an extreme OH/IR star candidate NSV 17351 are presented. Using the VERA (VLBI Exploration of Radio Astrometry) VLBI array , we observed 22 GHz H2O masers of NSV 17351 and derived an annual parallax of 0.247 ± 0.035 mas, which corresponds to a distance of 4.05 ± 0.59 kpc, from the observation. By averaging proper motions of 15 maser spots further, we determined the systemic proper motion of NSV 17351 to be (μαcos δ, μδ)avg. = (−1.19 ± 0.11, 1.30 ± 0.19) mas yr−1. The maser spots spread out over a region of 20 × 30 mas, which can be converted to a spatial distribution of ∼80 × 120 au at the source distance. Internal motions of the maser spots suggest an outward-moving maser region with respect to the estimated position of the central star. From single-dish monitoring of the H2O maser emission, we estimate the pulsation period of NSV 17351 to be 1122 ± 24 d. This is the first report of the periodic activity of NSV 17351, indicating that NSV 17351 could have a mass of ∼4 M⊙. We confirmed that the time variation of H2O masers can be used as a period estimator of variable OH/IR stars. Furthermore, by inspecting dozens of double-peaked H2O maser spectra for the last 40 years, we discovered the long-term acceleration in the radial velocity of the circumstellar matter to be 0.17 ± 0.03 km s−1 yr−1. We finally determined the position and kinematics in the Milky Way Galaxy and found that NSV 17351 is located in an interarm region between the Outer and Perseus arms. We note that the astrometric VLBI observation toward extreme OH/IR stars shows us a useful sample of the Galactic dynamics.

Ethylene oxide monitor with part-per-trillion precision for in situ measurements

Abstract. An Aerodyne tunable infrared laser direct absorption spectrometer with a multipass cell with a 413 m pathlength for the detection of ethylene oxide (EtO) is presented (TILDAS-FD-EtO). This monitor achieves precisions of <75 ppt or <0.075 ppb s−1 and <20 ppt in 100 s (1σ). We demonstrate precisions averaging down to 4 ppt h−1 (1σ precision) when operated with frequent humidity-matched zeroes. A months-long record of 2022 ambient concentrations at a site in the eastern United States is presented. Average ambient EtO concentration is on the order of 18 ppt (22 ppt standard deviation, SD). Enhancement events of EtO lasting a few hours are observed, with peaks as high as 600 ppt. Back-trajectory simulations suggest an EtO source nearly 35 km away. This source along with another are confirmed as emitters through mobile near-source measurements, with downwind concentrations in the 0.5 to 700 ppb range depending on source identity and distance downwind.

Characterizing a supernova’s standing accretion shock instability with neutrinos and gravitational waves

We perform a novel multimessenger analysis for the identification and parameter estimation of the standing accretion shock instability (SASI) in a core-collapse supernova with neutrino and gravitational-wave (GW) signals. In the neutrino channel, this method performs a likelihood ratio test for the presence of SASI in the frequency domain. For gravitational-wave signals we process an event with a modified constrained likelihood method. Using simulated supernova signals, the properties of the Hyper-Kamiokande neutrino detector, and O3 LIGO interferometric data, we produce the two-dimensional probability density function (PDF) of the SASI activity indicator and calculate the probability of detection PD as well as the false identification probability PFI. We discuss the probability to establish the presence of the SASI as a function of the source distance in each observational channel, as well as jointly. Compared to a single-messenger approach, the joint analysis results in a PD (at PFI=0.1) of SASI activities that is larger by up to ≈40% for a distance to the supernova of 5 kpc. We also discuss how accurately the frequency and duration of the SASI activity can be estimated in each channel separately. Our methodology is suitable for implementation in a realistic data analysis and a multimessenger setting.8 MoreReceived 24 November 2022Accepted 24 February 2023DOI:https://doi.org/10.1103/PhysRevD.107.083017© 2023 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasExtrasolar neutrino astronomyGravitational wavesNovae & supernovaeTechniquesGravitational wave detectionGravitational wave detectorsNeutrino detectorsGravitation, Cosmology & Astrophysics

Short-time diffusive fluxes over membrane receptors yields the direction of a signalling source.

An essential ability of many cell types is to detect stimuli in the form of shallow chemical gradients. Such cues may indicate the direction that new growth should occur, or the location of a mate. Amplification of these faint signals is due to intra-cellular mechanisms, while the cue itself is generated by the noisy arrival of signalling molecules to surface bound membrane receptors. We employ a new hybrid numerical-asymptotic technique coupling matched asymptotic analysis and numerical inverse Laplace transform to rapidly and accurately solve the parabolic exterior problem describing the dynamic diffusive fluxes to receptors. We observe that equilibration occurs on long timescales, potentially limiting the usefulness of steady-state quantities for localization at practical biological timescales. We demonstrate that directional information is encoded primarily in early arrivals to the receptors, while equilibrium quantities inform on source distance. We develop a new homogenization result showing that complex receptor configurations can be replaced by a uniform effective condition. In the extreme scenario where the cell adopts the angular direction of the first impact, we show this estimate to be surprisingly accurate.

Marmots do not drink coffee: Human urine contributions to the nitrogen budget of a popular national park destination

AbstractReactive nitrogen (Nr) concentrations are higher than expected for mountain lakes in Rocky Mountain National Park, and for many years, high Nr concentrations have been attributed to atmospheric Nr deposition from regional and more distant emission sources, including combustion of fossil fuels and agricultural activities. Here, we estimated the contribution from a very local source, that of human urine, related to intensive use by visitors in Loch Vale Watershed (LVWS). Not only does urine convey hormones, pharmaceuticals, antibiotic‐resistant bacteria, and antibiotic‐resistant genes to the environment, but it also contributes Nr, which contributes to loss of biodiversity and eutrophication. Using caffeine as a specific marker for human urine, we compared the calculated maximum potential input of urine with that from wet atmospheric Nr deposition. The maximum potential input is a worst‐case scenario. Nearly 30,000 and 45,000 people hiked the 4.0 km to the Loch, the lowest lake in LVWS, in June–September 2019 and 2020, respectively. Informal trails and informal latrine sites were mapped, and the contribution of human urine was calculated based on several assumptions, including that each visitor voided their bladder on the ground once per visit somewhere in Loch Vale. The resulting Nr input from urine in Loch Vale for the summer months of June through September was 0.02 kg Nr ha−1, and prorated to a full year, the 2019 potential contribution of human waste was 0.06 kg ha−1 year−1. These values are compared with June–September 1.2 kg Nr ha−1 from wet atmospheric deposition or annual measured 2019 deposition of 2.5 kg Nr ha−1 year−1, to indicate a contribution of 2% Nr to the waters of Loch Vale from local human urine. Most Nr in this alpine and subalpine watershed is still attributable to emissions and subsequent wet atmospheric deposition, but a 2% contribution from human waste is not insignificant. In the very broadest sense, our results document an ecological disturbance from an unprecedented level of human activity in a protected and designated wilderness area. Local solutions to this local problem could include greater outreach to visitors of public lands about the consequences of their activities and installation of latrines.

Assessment of entrance skin dose for adult patients undergoing diagnostic X-ray examinations in the Souss-Massa region of Morocco

The objective of this study is to evaluate the Entrance Skin Dose (ESD), and to establish the Diagnostic Reference Levels (DRLs) for the most common X-ray examinations in adult patients in the Souss-Massa region of Morocco. Data from 720 adult patients in four radiology departments in the Souss-Massa region were collected. The data concerned the following examinations: thorax posterior anterior (PA), unprepared abdominal X-ray, pelvis, hip, cervical spine anterior-posterior (AP) and lateral (Lat), lumbar spine anterior-posterior (AP) and lateral (Lat). The following parameters were reported for each examination: age, weight, patient thickness, voltage (kV), electrical charge (mAs), and the skin source distance. The Entrance Skin Dose and the Diagnostic Reference Levels are calculated for each X-ray examination. DRLs in terms of ESD for the same X-ray examination differ widely from one hospital to another. They ranged from 3 to 14 mGy for the unprepared abdominal X-ray, from 2.6 to 9.4 mGy for the pelvis, from 3.1 to 17 mGy for the hip, from 1 to 49.2 mGy for the cervical spine Lat, from 2 to 32.6 mGy for the lumbar spine AP, and from 18.1 to 50 mGy for the lumbar spine Lat. The variation of doses received by patients in the four hospitals calls into question radiological procedures and practices and calls for a standardization of guidelines for each radiological examination.

Detection and Localization of Multiple Ships Using Acoustic Vector Sensors on Buoyancy Gliders: Practical Design Considerations and Experimental Verifications

Real-time detection of illegal activities in maritime areas, such as drug trafficking or illegal fishing, is a very challenging task. It generally requires important and expensive means (patrol planes, coastguard, or navy ships) to provide an efficient monitoring of large areas. As ships emit noise due to their propulsion (propeller and engines), passive acoustic monitoring can be an effective alternative to accomplish this task, at a reasonable cost. To be efficient, the detection process should be autonomous, run in real-time, and should transmit information within a short period. In this study, we demonstrate the potential of using gliders equipped with a tri-dimensional acoustic vector sensor (AVS) to run a survey mission in total autonomy. Based on the ability of the AVS to measure the direction of arrival of the incoming wave, we develop an embedded and real-time processing chain to detect ships and to cluster detections in a multiple-sources scenario. We also propose a receiver that runs in real time to measure the time difference of arrival (TDOA) if multipath propagation occurs. The sonar contacts are transmitted every 30 s to a command and control (C2) station using an acoustic modem, without interrupting the detection process. The C2 can process the sonar contacts with a tracker for target localization; the article also shows that it is possible to get a good estimate of the source distance by processing the TDOA from multipath propagation. The proposed methods are validated on data recorded during an at-sea experiment in shallow waters.

Próba porównania niektórych elementów instytucji przyczynienia się poszkodowanego w deliktowej odpowiedzialności za szkody na osobie w prawie polskim i w systemie common law / Attempt at a Comparative Analysis of Certain Elements of Contributory Negligence of the Injured in Tortious Liability for Personal Injury Under the Polish Law and in the Common Law System

The article provides a comparative analysis of the approaches related to contributory negligence of the injured causing the occurrence or aggravation of the injury in the Polish law and in the common law system. The article discusses the development of this institution, differences and similarities with special emphasis on the latter as peculiar to the systems that evolved from such distant sources as well as rules according to which the occurrence and degree of contribution is established. The basis for deliberations is the legislation of England and Wales under which this institution developed, from a chronological perspective, for the first time. However, certain American, Canadian and Australian approaches have also been discussed against this background. The article addresses important issues, though rarely debated in the Polish legal literature, and constitutes an important source of knowledge for legal scholars providing professional insights and prompting both axiological and purely practical deliberations. em Key words: tortious liability, personal injury, comparative negligence, contributory negligence, the common law system

Analysis of annual citizen odor observation records and its relationship with meteorological factors: Çorlu / Tekirdağ case study

Odor pollution is a primary environmental problem and the most frequent public complaint. The emission levels of air pollutants, the distance of emission sources from residential areas, and topography and other geographical and meteorological conditions influence the level and intensity of air and odor pollution. Owing to the lack of standard management approaches, citizen survey studies supported by geographic information systems have become critical in collecting odor observation data in the immission site. In this study, FIDOL (frequency, intensity, duration, odor tone, and location) factor-based annual odor observation data were collected, using the Çorlu KODER mobile application. Statistical analysis determined whether meteorological factors affected the average daily number of odor observations (NOOs) throughout the year. Temperature was the meteorological factor with the most significant effect on the increase in average daily NOOs. Furthermore, it was determined whether the Hybrid Single-Particle Lagrangian Integrated Trajectory model estimated the mixed layer height (MLH) and relative humidity (RH) parameters that significantly affected the average daily NOOs during August 2021–October 2021. This period was considered critical because over 80% of the annual NOOs occurred within this timeframe. MLH, RH, and MLH–RH significantly affected the average daily NOOs. Analysis using the Sturges classification revealed that odor observations were mainly intensified under low RH and MLH conditions. I In addition, the frequency of odor episodes increased under low MLH conditions. Seven consecutive odor episodes between August and October 2021 were further analyzed, considering the spatial and temporal distribution of odor observations, MLH and RH values, and back-trajectory findings. Analysis based on the air pollutant transport mechanism suggested that almost all of the odor episodes experienced in Çorlu within the study period were related to emissions from the organized industrial zone (OIZ) regions. The findings suggest that emissions from the OIZs located in the north-east and north of Çorlu have a more intense effect on odor observations in Çorlu residential areas.

Late Pleistocene dynamics of dust emissions related to westerlies revealed by quantifying loess provenance changes in North Tian Shan, Central Asia

Wind-blown loess, as the geological record of dust, is a promising archive to explore paleoclimate change and paleo-dust cycle from source to sink over the westerly-dominated Central Asia (CA). However, it is still not fully established how loess deposition in CA physically connects to the westerlies. In this study, based on trace element analyses of the Nilka (NLK) loess section from eastern Ili Basin, we used sediment source fingerprinting (SSF) and random forest (RF) to quantitatively restore loess provenance changes in North Tian Shan, CA, covering the past 71 ka. The results reveal that alluvium and proluvial on the piedmont slopes/plains over the region served as the primary sources for the NLK loess (averaging ∼ 72 %), with less contributions of deserts (∼28 %). The temporal variations of the major source contributions, combined with density plots of the RF results, suggest that the enhanced westerly-linked moisture transport controlled by both obliquity and precession forcings has largely suppressed the loess accumulation despite the possibility that the strengthened westerlies led to the increased supply of the distant sources. This indicates an intimate linkage between the SSF results, the local paleoenvironment and the large-scale paleoclimatic systems. In addition, the relatively smaller contributing proportions of the Kazakh deserts confirm that the CA loess is not mainly derived from the deserts. In conclusion, quantifying loess provenance changes here represents one potential approach for resolving the relationships between dust cycles and climate forcings, which is relevant for paleoclimate reconstruction based on the comparatively patchy (non-plateau) piedmont loess in CA.

Rapid Movement of ‘Candidatus Liberibacter asiaticus’ on ‘Hamlin’ Sweet Orange and ‘Swingle’ Citrumelo Trunks

Huanglongbing (HLB), caused by phloem-limited ‘ Candidatus Liberibacter asiaticus’ (CLas), is the primary limiting factor of production in most citrus regions of the world. After infection, CLas is transported systemically throughout the phloem tissues following the source-sink movement. Split-root rhizoboxes and one-sided graft inoculation above the split trunk was used to understand if the vertical distance of the inoculum source and different anatomical structures (grafted or seedling trees) can affect the speed of the CLas movement, as well as the effects of the seasonality on these movements. The time for CLas to reach the roots was not affected by either distance of the inoculum source or tree type. The seasonal infection period appears to have an important effect on CLas movement. Trees inoculated in the summer had fast and uniform movement (first detection at 4 weeks after inoculation). Plants inoculated in the winter had a slow and uneven movement (first CLas detection at 14 weeks after inoculation). Our results indicate that summer and spring are the seasons of CLas down and lateral movement, but this is independent of the vertical distance of the inoculum source or anatomical structures of the plants. The findings from this study aid in the management of HLB in the field, as well as improve the methods for CLas detection. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY 4.0 International license .

Study of parameters influence on the measurement of vacuum level in parabolic trough collectors’ receivers using infrared thermography

The receiver tube of the parabolic trough collectors may suffer a degradation of the vacuum atmosphere between the glass envelope and the absorber tube due to the permeation of gases, mainly hydrogen or air. This is one of the most common issues of heat loss increase in solar fields with this type of solar collectors. The Surface Temperature Method has been used to determine the complete and partial vacuum loss in the annulus of receiver tubes, by measuring the temperature of the glass envelope. In this work, the influences of the meteorological variables and the source distance on the measurement of the temperature by infrared thermography are analysed, as well as the feasibility of using the reflector of the collector itself to measure the sky temperature, parameter necessary to correctly measure the temperature by means of an infrared sensor.

The first balloon-borne sample analysis of atmospheric carbonaceous components reveals new insights into formation processes

Atmospheric aerosol optical, physical, and chemical properties play a fundamental role in the Earth's climate system. A better understanding of the processes involved in their formation, evolution, and interaction with radiation and the water cycle is critical. We report the analysis of atmospheric molecules/particles collected with a new sampling system that flew under regular weather balloons for the first time. The flight took place on January 18, 2022 from Reims (France). The samples were subsequently analyzed by high-resolution mass spectrometry (Orbitrap) to specifically infer hundreds of organic components present in 4 different layers from the troposphere to the stratosphere (up to 20 km). Additional measurements of O3, CO, and aerosol concentrations a few hours before this flight took place to contextualize the sampling. After separating common species found on each filter that might be common to atmospheric layers or residuals for contaminations, we found that each sample yields significant differences in the number and size of organic species detected that should reflect the unique composition of atmospheric layers. While tropospheric samples yield significantly oxidized and saturated components, with carbon numbers below 30 that might be explained by complex organics chemistry from local and distant source emissions, the upper tropospheric and stratospheric samples were associated with increased carbon numbers (C > 30), with a significantly reduced unsaturation number for the stratosphere, that might be induced by strong UV radiations. The multimodal distributions of carbon numbers in chemical formulas observed between 15 and 20 km suggest that oligomerization and growth of organic molecules may take place in aged air masses of tropical origin that are known to carry organic compounds even several km above the tropopause where their lifetime significantly increases. In addition, the presence of organics may also reflect the extended influence of wildfires smoke injected during the spring and summer in the NH hemisphere before the in situ observations and their long-lifetime in the upper troposphere and stratosphere.

Utilization of different radionuclides for high-energy extended efficiency calibration of a HPGe for improved determination of calcium and sulfur using k0-INAA

The present study reports on the performance of three reactor-produced radionuclides (24Na, 56Mn, and 72Ga) and one accelerator-produced radionuclide (56Co) for extending the full-energy peak efficiency calibration of a coaxial HPGe detector up to ~ 3100 keV at different detector to source distances. The differences between the efficiency curves obtained with and without the use of high-energy gamma emitters radionuclides have a considerable impact on the accuracy of the Na, Ca, and S determination by the k0-INAA as evidenced by analysis results of reference materials. The results revealed that 24Na is the most suitable radionuclide for high-energy efficiency calibration due to its reasonable availability, low production cost, simple decay scheme, and well-defined decay properties.

Process design analysis of a hybrid power-and-biomass-to-liquid process – An approach combining life cycle and techno-economic assessment

Techno-economically and ecologically optimized processes require understanding of trade-offs between efficiencies, costs and environmental impacts. For this purpose, DLR’s in-house tool TEPET for techno-economic analysis was enhanced to enable simultaneous life cycle assessment (LCA). Within this study a hybrid Power-and-Biomass-to-Liquid concept is analysed that can switch between a biomass alone and hydrogen enhanced operation. In order to integrate the techno-economic and ecological results, a dimensionless cost-impact factor is introduced, which gets minimised when both costs and environmental impacts are low. The methodology is applied to investigate process parameter variations within this process concept. The varied process parameters are H2/CO ratio, H2 conversion in the Fischer-Tropsch synthesis and CO2 recycle rate to the gasification. Furthermore, the influence of LCA allocation methods on the preferable set of process parameters was examined. Results show a correlation of lowest environmental impact with high fuel efficiency (energetic fuel output per overall energetic input) for economic allocation. For energetic allocation, high process efficiency (ratio of overall energetic output to overall energetic input) leads to the lowest environmental impact. High carbon efficiency is especially important when biomass has a big impact on a certain category. Sensitivity studies for the global warming potential demonstrate a low sensitivity to the investigated process parameter variations compared with changes in input parameters like biomass and electricity source or transport distance. As the net production cost (NPC) are more sensitive towards the process parameter variations, the cost-impact factor is lowest for the set of process parameters with the lowest NPC.

Deep tubewell use is associated with increased household microbial contamination in rural Bangladesh: Results from a prospective cohort study among households in rural Bangladesh

Deep tubewells are important sources of arsenic mitigation in rural Bangladesh. Compared to commonly available shallow tubewells, deep tubewells tap into deeper low-arsenic aquifers and greatly reduce exposure to arsenic in drinking-water. However, benefits from these more distant and expensive sources may be compromised by higher levels of microbial contamination at point-of-use (POU). This paper examines differences in microbial contamination levels at source and POU among households using deep tubewells and shallow tubewells, and investigates factors associated with POU microbial contamination among deep tubewell users. We assessed a prospective longitudinal cohort of 500 rural households in Matlab, Bangladesh, across 135 villages. Concentration of Escherichia coli (E. coli) in water samples at source and POU using Compartment Bag Tests (CBTs) was measured across rainy and dry seasons. We employed linear mixed-effect regression models to measure the effect of different factors on log E. coli concentrations among deep tubewell users. CBT results show that log E. coli concentrations are similar at source and at POU during the first dry and rainy season, but are significantly higher at POU among deep tubewell users during the second dry season. Log E. coli at POU among deep tubewell users is positively associated with both presence (exponentiated beta exp(b) = 2.52, 95% Confidence Interval (CI) = 1.70, 3.73) and concentration of E. coli (exp(b) = 1.36, 95% CI = 1.19, 1.54) at source, and walking time to the tubewell source (exp(b) = 1.39, 95% CI = 1.15, 1.69). Drinking-water during the second dry season is associated with reduced log E. coli (exp(b) = 0.33, 95% CI = 0.23, 0.57) compared to the rainy season. These results suggest that while households that use deep tubewells have lower arsenic exposure, they may be at higher risk of consuming microbially contaminated water compared to households that use shallow tubewells.

Utilization Management to Ensure Clean Water Sources in Coastal Areas

Coastal communities utilize tidal water sources; existing surface water does not meet clean water standards, and communities are greatly affected by current water use. Managing existing water sources to meet the needs of the community is very difficult to obtain, so research is needed to determine the quality, quantity, and distance of water sources needed to meet the standards. This study aims to determine the quality, quantity, and distance of water sources. This study used a descriptive qualitative approach, the observation method, a survey, a questionnaire, and documentation. Good water source management will ensure that everyone has enough water. October's highest surface water potential Q = 61.96 m3/s and April's low Q = 1.02 m3/s, highest Qt groundwater potential = 0.12 m3/s, and the lowest Qt = 0.05 m3/s. Water availability Q = 21.15 m3/s with a domestic demand rate Q = 0.127 m3/s and Q = 0.021 m3/s non-domestic. A suitable and compliant water source is located at point 5 at a distance of 9 km from the location of the coastal area, with 87% water quality and conditions Temperature, pH, NO3, NO2, TN, COD, BOD, and Chlo-a meet the standard value obtained at 0.2 mg/l, indicating that the condition is not contaminated and safe. Coastal water quality challenges demand research and prudent use management. Nature-based littoral zone management enhances water quality. Pollution management, sustainable water use, and community involvement safeguard coastal habitats, biodiversity, and water sources. Doi: 10.28991/HEF-2023-04-01-03 Full Text: PDF

Organic or junk food? Microplastic contamination in Antarctic krill and salps.

Microplastics (MP) have been reported in Southern Ocean (SO), where they are likely to encounter Antarctic zooplankton and enter pelagic food webs. Here we assess the presence of MP within Antarctic krill (Euphausia superba) and salps (Salpa thompsoni) and quantify their abundance and type by micro-Fourier transform infrared microscopy. MP were found in both species, with fibres being more abundant than fragments (krill: 56.25% and salps: 22.32% of the total MP). Polymer identification indicated MP originated from both local and distant sources. Our findings prove how in situ MP ingestion from these organisms is a real and ongoing process in the SO. MP amount was higher in krill (2.13 ± 0.26 MP ind-1) than salps (1.38 ± 0.42 MP ind-1), while MP size extracted from krill (130 ± 30 µm) was significantly lower than MP size from salps (330 ± 50 µm). We suggest that differences between abundance and size of MP ingested by these two species may be related to their food strategies, their ability to fragment MP as well as different human pressures within the collection areas of the study region. First comparative field-based evidence of MP in both krill and salps, two emblematic zooplankton species of the SO marine ecosystems, underlines that Antarctic marine ecosystems may be particularly sensitive to plastic pollution.

Reconstructing the extended structure of multiple sources strongly lensed by the ultra-massive elliptical galaxy SDSS J0100+1818

We study the total and baryonic mass distributions of the deflector SDSS J0100+1818 through a full strong lensing analysis. The system is composed of an ultra-massive early-type galaxy at z = 0.581, with a total stellar mass of (1.5 ± 0.3)×1012 M⊙ and a stellar velocity dispersion of (450 ± 40) km s−1, surrounded by ten multiple images of three background sources, two of which are spectroscopically confirmed at z = 1.880. We took advantage of high-resolution HST photometry and VLT/X-shooter spectroscopy to measure the positions of the multiple images and performed a strong lensing study with the software GLEE. We tested different total mass profiles for the lens and modeled the background sources first as point-like and then as extended objects. We successfully predict the positions of the observed multiple images and reconstruct over approximately 7200 HST pixels the complex surface brightness distributions of the sources. We measured the cumulative total mass profile of the lens and find a total mass value of (9.1 ± 0.1)×1012 M⊙, within the Einstein radius of approximately 42 kpc, and stellar-over-total mass fractions ranging from (49 ± 12)%, at the half-light radius (Re = 9.3 kpc) of the lens galaxy, to (10 ± 2)%, in the outer regions (R = 70 kpc). These results suggest that the baryonic mass component of SDSS J0100+1818 is very concentrated in its core and that the lens early-type galaxy (or group) is immersed in a massive dark matter halo, which allows it to act as a powerful gravitational lens, creating multiple images with exceptional angular separations. This is consistent with what has been found in other ultra-high-mass candidates at intermediate redshift. We also measured the physical sizes of the distant sources, resolving them down to a few hundred parsecs. Finally, we quantify and discuss a relevant source of systematic uncertainties on the reconstructed sizes of background galaxies, associated with the adopted lens total mass model.