bluuebunny/crossref_metadata_2025 huggingface dataset:
Theab initiopotential energy curves of atom pairs and transport properties of high-temperature vapors of Cu and Si and their mixtures with He, Ar, and Xe gases
Authors: Kayang Kevin W. , Volkov Alexey N. , Zhilyaev Petr A. , Sharipov Felix
Published: January 2023

Theab initiopotential energy curves for the He–He, Ar–Ar, Cu–Cu, Si–Si, Cu–He, Cu–Ar, Cu–Xe, Si–He, Si–Ar, and Si–Xe dimers are obtained and used to find the transport coefficients of Cu and Si vapors and their mixtures with He, Ar, and Xe gases.
Enhanced electrochemical hydrogen oxidation reaction and suppressed hydrogen peroxide generation properties on Pt/Ir(111) bimetallic surfaces
Authors: Hayashi Kenta , Tomimori Takeru , Sato Riku , Todoroki Naoto , Wadayama Toshimasa
Published: January 2023

A Pt0.3ML/Ir(111) model catalyst showed desirable properties for a polymer electrolyte fuel cell anode, including enhanced hydrogen oxidation activity and suppressed H2O2 generation.
Diffusion of hydrophilic to hydrophobic forms of Nile red in aqueous C12EO10 gels by variable area fluorescence correlation spectroscopy
Authors: Shafiee Omid , Jenkins Samantha G. , Ito Takashi , Higgins Daniel A.
Published: January 2023

Variable area fluorescence correlation spectroscopy is used to study diffusion by three Nile red derivatives within aqueous C12EO10 lyotropic liquid crystal gels. The dyes exhibit different levels of interactions with the micelle cores in the gels.
Laser induced white emission generation from La1−xNdxAlO3 nanocrystals
Authors: Gonçalves João Marcos , Stefanski Mariusz , Tomala Robert , Musialek Agata , Strek Wieslaw
Published: January 2023

Focused 808 nm excitation was able to produce bright warm white light from La1-xNdxAlO3 nanocrystals. The concentration of Nd3+ influenced the intensity dependence on power and pressure along with the photoconductivity. An IVCT mechanism was proposed.
Quantifiable polarity match effect on C–H bond cleavage reactivity and its limits in reaction design
Authors: Maldonado-Domínguez Mauricio , Srnec Martin
Published: January 2023

When oxidants favour cleaving a strong C–H bond at the expense of weaker ones, which are otherwise inherently preferred due to their favourable reaction energy, reactivity factors such as the polarity match effect are often invoked.
On the mercuration, palladation, transmetalation and direct auration of a C^N^C pincer ligand
Authors: McEllin Alice Jane , Goult Christopher A. , Whitwood Adrian C. , Lynam Jason M. , Bruce Duncan W.
Published: January 2023

The C^N^C pincer ligand shown may be aurated via a well-characterised dimercury(ii) complex, a dinuclear palladium(ii) complex or directly using a rhodium(iii) catalyst.
Laser-assisted protein micropatterning in a thermoplastic device for multiplexed prostate cancer biomarker detection
Authors: Kling André , Dirscherl Lorin , Dittrich Petra S.
Published: January 2023

We introduce a thermoplastic microfluidic device for the detection of cancer biomarkers by competitive immunoassays. Immobilization of different antibody-protein pairs is achieved by laser-assisted protein adsorption by photobleaching.
Biphenyl furanocoumarin compounds inhibit SARS-CoV-2 spike pseudovirus infection by binding ACE2
Authors: Lv Yuexin , Ge Shuai , Zhu Qiumei , Si Min , Wang Cheng , He Huaizhen
Published: January 2023

Three biphenyl furanocoumarin compounds have significant effects on inhibiting pseudovirus invasion into cells.
Optical sensor arrays for the detection and discrimination of natural products
Authors: Yang Maohua , Zhang Mei , Jia Mingyan
Published: January 2023

This review provides a brief introduction to the optical sensor array and focuses on its progress toward the detection and discrimination of natural products.
Chiral inorganic nanomaterials for biological applications
Authors: Wang Fang , Yue Xiaoyong , Ding Qi , Lin Hengwei , Xu Chuanlai , Li Si
Published: January 2023

This review summarizes the works regarding chiral inorganic nanomaterials with bio-functions and bio-applications, which can deep our understanding on chiral inorganic nanomaterials' construction principles and biological functional properties.
PhI(OAc)2/Pd(OAc)2 promoted the formation of 8-hydroxyquinoline derivatives from benzoxazoles and alcohols
Authors: Wu Qingkun , Hou Jingxuan , Gu Qingshan , Gao Hui , Shi Meiqi , Zheng Lu
Published: January 2023

A PIDA/Pd(OAc)2 system that synergistically promotes the formation of 8-hydroxyquinoline derivatives from benzoxazoles and alcohols has been developed. The reaction proceeded smoothly with a range of benzoxazoles and alcohols in moderate yields.
Copper-responsive liposomes for triggered cargo release employing a picolinamide−lipid conjugate
Authors: Sagar Ruhani , Jaremba Emily A. , Lou Jinchao , Best Michael D.
Published: January 2023

We report a copper-responsive liposomal platform for which triggered release of encapsulated hydrophilic cargo is driven by copper binding to a picolinamide–lipid conjugate that acts as a lipid switch by altering lipid self-assembly properties.
Microwave-assisted rapid synthesis of chiral oxazolines
Authors: Deng Haowen , Wang Jianshe , He Wei , Ye Yang , Bai Renren , Zhang Xuelei , Ye Xiang-Yang , Xie Tian , Hui Zi
Published: January 2023

A practical protocol involving microwave-assisted cyclization of nitriles and chiral amino indanols has been successfully developed. This enables quick access to chiral oxazolines using a reusable catalyst in a much shorter reaction time.
Aqueous RAFT polymerization-induced self-assembly (PISA): amphiphilic macroRAFT self-assembly vs. monomer droplet nucleation (miniemulsion polymerization)
Authors: Kim Hyun Jin , Ishizuka Fumi , Chatani Shunsuke , Niino Hiroshi , Zetterlund Per B.
Published: January 2023

The effect of monomer droplet size on the particle formation mechanism in aqueous heterogeneous polymerization using a hydrophilic macroRAFT agent has been investigated.
Temporal quantitative profiling of sialyllactoses and sialic acids after oral administration of sialyllactose to mini-pigs with osteoarthritis
Authors: Park Dan Bi , Kim Lila , Hwang Jeong Ho , Kim Kyung-Tai , Park Ji Eun , Choi Jong-Soon , An Hyun Joo
Published: January 2023

In this work, we demonstrate the bioavailability of dietary sialyllactose by concentration–time profiles in an osteoarthritis mini-pig model and suggest a potential therapeutic effect of sialyllactose on osteoarthritis.
Substrate mediated properties of gold monolayers on SiC
Authors: Shtepliuk Ivan , Yakimova Rositsa
Published: January 2023

In light of their unique physicochemical properties two-dimensional metals are of interest in the development of next-generation sustainable sensing and catalytic applications.
Experimental and ab initio studies on the structural, magnetic, photocatalytic, and antibacterial properties of Cu-doped ZnO nanoparticles
Authors: Tsogoo Ariunzaya , Tsedev Ninjbadgar , Gibaud Alain , Daniel Philippe , Kassiba Abdelhadi , Fukuda Masayuki , Kusano Yoshihiro , Azuma Masaki , Tsogbadrakh Namsrai , Ragchaa Galbadrakh , Dashzeveg Rentsenmyadag , Ganbold Erdene-Ochir
Published: January 2023

Magnetic, photocatalytic and antibacterial performance of ZnO NPs were enhanced as doped with Cu.
Bond breaking of furan–maleimide adducts via a diradical sequential mechanism under an external mechanical force
Authors: Cardosa-Gutierrez Manuel , De Bo Guillaume , Duwez Anne-Sophie , Remacle Francoise
Published: January 2023

An external mechanical force larger than 1 nN induces a switch from a concerted to a stepwise mechanism in the rupture of proximal dimethyl furan–maleimide [4 + 2] Diels–Alder adducts. The intermediate formed after the first bond rupture has a diradical character.
Overcoming the entropy of polymer chains by making a plane with terminal groups: a thermoplastic PDMS with a long-range 1D structural order
Authors: Chen Yugen , Ishiwari Fumitaka , Fukui Tomoya , Kajitani Takashi , Liu Haonan , Liang Xiaobin , Nakajima Ken , Tokita Masatoshi , Fukushima Takanori
Published: January 2023

Subtle modification, adding methoxy groups to the triptycene termini of a telechelic polydimethylsiloxane (PDMS), dramatically improves mechanical properties, forming a thermoplastic PDMS without the need for covalent cross-linking.
The spatial distribution of cobalt phthalocyanine and copper nanocubes controls the selectivity towards C2 products in tandem electrocatalytic CO2 reduction
Authors: Wang Min , Loiudice Anna , Okatenko Valery , Sharp Ian D. , Buonsanti Raffaella
Published: January 2023

This work highlights the importance of a direct contact between the CO-generating molecular catalyst and the Cu catalyst to promote C–C coupling in tandem electrocatalytic CO2 reduction.
Fluid manipulationviamultifunctional lubricant infused slippery surfaces: principle, design and applications
Authors: Wang Xinsheng , Bai Haoyu , Li Zhe , Cao Moyuan
Published: January 2023

Water-repellent interfaces with high performance have emerged as an indispensable platform for developing advanced materials and devices.
FeRu-based metal–organic framework bifunctional catalysts for hydrogen production and methanol electroreforming
Authors: Ling Qi , Zhao Ziwei , Li Ziliang , Yan Kui , Ding Chunsheng , Chen Peng , Sun Zhaoqi , He Gang , Lv Jianguo , Zhang Miao
Published: January 2023

FeRu-MOF/NF was prepared via one-step solvothermal method on nickel foam (NF). Bifunctional electrode FeRu-MOF (100 : 3)/NF‖FeRu-MOF (100 : 3)/NF showed excellent performance in methanol–water electrolyte with >90% Faraday efficiencies for both cathode and anode products.
Bioinspired hollow porous fibers with low emissivity and conductivity aluminum platelet skin for thermal insulation
Authors: Hu Rongjun , Hou Lanlan , Liu Jingchong , Cui Zhimin , Miao Beibei , Bai Jie , Man Xingkun , Wang Nü , Jiang Lei , Zhao Yong
Published: January 2023

Hollow porous fibers with low emissivity and conductivity aluminum platelets skin for thermal insulation.
Limiting phase separation via halogen-free solvent slot-die processing enables highly efficient and eco-friendly all-polymer solar cells
Authors: Wu Baohua , Kong Yuxin , Zhu Qinglian , Zhang Sen , Lin Baojun , Zhao Heng , Xue Jingwei , Seibt Susanne , Zhou Ke , Li Yuxiang , Ma Wei
Published: January 2023

High-performance eco-friendly all-polymer solar cells were realized by balancing the crystallinity and domain size via hot halogen-free solvent slot-die coating.
HPIM‐DM: A fast and reliable dense‐mode multicast routing protocol
Authors: Oliveira Pedro , Silva Alexandre , Valadas Rui
Published: January 2023

The Hard‐state Protocol Independent Multicast—Dense Mode (HPIM‐DM) multicast routing protocol is proposed. HPIM‐DM is a hard‐state version of PIM‐DM that overcomes its poor convergence times and lack of resilience to replay attacks. Like PIM‐DM, HPIM‐DM is meant for dense networks and supports its operation on a unicast routing protocol and reverse path forwarding. However, routers maintain sense of the multicast trees at all times, allowing fast reconfiguration in the presence of network failures or unicast route changes. This is achieved by (i) keeping information on all upstream neighbours from which multicast data can be received, (ii) ensuring the reliable transmission and sequencing of control messages, and (iii) synchronizing the routing information immediately when a new router joins the network. The correctness of the protocol was extensively validated using model checking and logical reasoning. The protocol was fully implemented in Python, and the implementation is publicly available. Finally, we show both theoretically and experimentally that HPIM‐DM has much better convergence times than PIM‐DM.
High‐speed high‐voltage solid‐state Marx generator based on SiC MOSFETs
Authors: Dehghan S. Mohammad , Seviour Rebecca , Hunt Steve
Published: January 2023

This paper presents a high‐speed, high‐voltage, solid‐state Marx generator based on silicon carbide MOSFETs. The objective was to develop a high‐rate repetitive, short‐pulse, high‐voltage and efficient generator for medical particle accelerator applications. To achieve this goal, a 720 kV Marx generator forming from 1445 kV stages was designed. Each stage includes several SiC devices in series to reach desired voltage and speed. Compared to the existing Marx generators, the proposed Marx generator is capable of producing shorter pulses with higher voltage. We present the experimental results of a three‐stage prototype Marx generator capable of producing 15 kV at 40 A output with a 200 nS pulse with a repetition rate of 500 Hz.
Integrating black start capabilities into offshore wind farms by grid‐forming batteries
Authors: Pagnani Daniela , Kocewiak Łukasz , Hjerrild Jesper , Blaabjerg Frede , Bak Claus Leth
Published: January 2023

Power systems are currently experiencing a transition towards decarbonisation through the large‐scale deployment of renewable energy sources. These are gradually replacing conventional thermal power plants which today are the main providers of black start services. Consequently, in case of a total/partial blackout, conventional black‐start resources may not be ready for operation. Offshore wind farms (OWFs), with their large capacity and fast controllers, have potential as innovative black‐start units, thus, the need for a new design for OWFs. Here, challenges and possible solutions in integrating black start services into offshore wind farms will be presented. The first challenge is represented by the self‐start capability. The self‐start unit should be capable of forming the wind farm power island and withstanding transient phenomena due to the equipment energisation. The investigated solution comprises grid‐forming (GFM) converters in the wind farm design, which could be battery energy storage systems (BESSs) to also increase the service availability. The challenges are analysed using simulations on a wind farm, and the proposed solutions are discussed. It can be concluded that a hybrid system comprised of a BESS and an OWF, with GFM control, applying soft‐charging, etc., represents a good proposal to provide black start services by OWFs.
Anatomy of rocky planets formed by rapid pebble accretion
Authors: Johansen Anders , Ronnet Thomas , Schiller Martin , Deng Zhengbin , Bizzarro Martin
Published: January 2023

We present a series of papers dedicated to modelling the accretion and differentiation of rocky planets that form by pebble accretion within the lifetime of the protoplanetary disc. In this first paper, we focus on how the accreted ice determines the distribution of iron between the mantle (oxidized FeO and FeO1.5) and the core (metallic Fe and FeS). We find that an initial primitive composition of ice-rich material leads, upon heating by the decay of26Al, to extensive water flow and the formation of clay minerals inside planetesimals. Metallic iron dissolves in liquid water and precipitates as oxidized magnetite Fe3O4. Further heating by26Al destabilizes the clay at a temperature of around 900 K. The released supercritical water ejects the entire water content from the planetesimal. Upon reaching the silicate melting temperature of 1700 K, planetesimals further differentiate into a core (made mainly of iron sulfide FeS) and a mantle with a high fraction of oxidized iron. We propose that the asteroid Vesta’s significant FeO fraction in the mantle is a testimony of its original ice content. We consider Vesta to be a surviving member of the population of protoplanets from which Mars, Earth, and Venus grew by pebble accretion. We show that the increase in the core mass fraction and decrease in FeO contents with increasing planetary mass (in the sequence Vesta – Mars – Earth) is naturally explained by the growth of terrestrial planets outside of the water ice line through accretion of pebbles containing iron that was dominantly in metallic form with an intrinsically low oxidation degree.
Magnetic field amplification and structure formation by the Rayleigh-Taylor instability
Authors: Popescu Braileanu B. , Lukin V. S. , Khomenko E.
Published: January 2023

We report our results from a set of high-resolution, two-fluid, non-linear simulations of the magnetized Rayleigh Taylor instability (RTI) at the interface between a solar prominence and the corona. These data follow results reported earlier on linear and early non-linear RTI dynamics in this environment. This paper is focused on the generation and amplification of magnetic structures by RTI. The simulations use a two-fluid model that includes collisions between neutrals and charges, including ionization and recombination, energy and momentum transfer, and frictional heating. The 2.5D magnetized RTI simulations demonstrate that in a fully developed state of RTI, a large fraction of the gravitational energy of a prominence thread can be converted into quasi-turbulent energy of the magnetic field. The RTI magnetic energy generation is further accompanied by magnetic and plasma density structure formation, including dynamic formation, break-up, and merging of current sheets and plasmoid sub-structures. The flow decoupling between neutrals and charges, as well as ionization and recombination reactions, are shown to have significant impact on the structure formation in a magnetized RTI.
Near-Earth object 2022 EB5: From atmospheric entry to physical properties and orbit
Authors: Geng S. , Zhou B. , Li M.
Published: January 2023

Context. The near-Earth object (NEO) 2022 EB5 is the fifth NEO found prior to entering the Earth's atmosphere. It fragmented over the Norway Sea on 2022 March 11 about two hours after being discovered by the astronomer Krisztián Sárneczky at Konkoly Observatory in Hungary. The Center for Near-Earth Object Studies (CNEOS) at NASA detected the visible radiation emitted at the time of its atmospheric entry. The Jet Propulsion Laboratory (JPL) and European Space Agency (ESA) derived its orbital elements based on observations of its pre-atmospheric orbit.

Aims. This paper aims to calculate the physical properties of this NEO, in particular, the bulk strength, type of the material, albedo, size, and mass, based on observations of its peak brightness at the time of its atmospheric entry. In addition, the heliocentric elements are computed from its interaction with Earth's atmosphere and compared with those derived from observations by JPL and ESA, respectively, to evaluate the accuracy of our method.

Methods. The flight equations of 2022 EB5 were inversely integrated from the peak brightness to the atmospheric boundary via the fourth-order Runge-Kutta method. A pancake model was utilized to simulate the fragmentation of the impactor. Parameters needed to complete the integration process that were unknown were set to be optimization variables and determined via a genetic algorithm.

Results. The results obtained show that 2022 EB5 was most likely a C-type asteroid with a maximal bulk strength of 2 MPa, diameter of 5–6 m, cometary density, and very low albedo that is no greater than 0.025. In addition, considering the effects of the atmosphere is helpful in getting a more accurate measurement for the semi-major axis, eccentricity, and inclination, although the accuracy of orbital elements strongly depends on the accuracy of USG sensors.
Beyond the two-infall model
Authors: Spitoni E. , Recio-Blanco A. , de Laverny P. , Palicio P. A. , Kordopatis G. , Schultheis M. , Contursi G. , Poggio E. , Romano D. , Matteucci F.
Published: January 2023

Context.The recentGaiaData Release 3 (DR3) represents an unparalleled revolution in Galactic archaeology, providing numerous radial velocities and chemical abundances for millions of stars as well as all-sky coverage.

AimsWe present a new chemical evolution model for the Galactic disc components (high- and low-αsequence stars) designed to reproduce the new abundance ratios provided by the General Stellar Parametriser-spectroscopy module for theGaiaDR3 and constrained by the detailed star formation (SF) histories for both the thick and thin disc stars inferred from previousGaiareleases.

Methods.Sophisticated modelling based on previousGaiareleases have found evidence for narrow episodes of enhanced SF inferred in recent time. Additionally,GaiaDR3 indicated the presence of young (massive) low-αdisc stars that show evidence of a recent chemical impoverishment in several elements. In order to reproduce these observables, we propose a new chemical evolution model in which the low-αsequence is generated by two distinct infall episodes. Hence, in this study we compareGaiaDR3 chemical abundances with the predictions of a three-infall chemical evolution model for the high- and low-αcomponents.

ResultsThe proposed three-infall chemical evolution model nicely reproduces the main features of the abundance ratio [X/Fe] versus [M/H] (X=Mg, Si, Ca, Ti,α) ofGaiaDR3 stars in different age bins for the consideredαelements. Moreover, the most recent gas infall – which started ∼2.7 Gyr ago – allowed us to predict accurately predict theGaiaDR3 young population which has experienced a recent chemical impoverishment.

Conclusions.We extended previous chemical evolution models designed to reproduce APOGEE and APOKASC data in order to predict newGaiaDR3 chemical abundances. To this aim, we proposed a three-infall chemical evolution model to better trace both (i) the young population inGaiaDR3 with evidence of chemical impoverishment and (ii) the SF history from previousGaiareleases.
Gaia DR3 view of dynamical substructure in the stellar halo near the Sun
Authors: Dodd Emma , Callingham Thomas M. , Helmi Amina , Matsuno Tadafumi , Ruiz-Lara Tomás , Balbinot Eduardo , Lövdal Sofie
Published: January 2023

Context. Debris from past merger events is expected and also known, to some extent, to populate the stellar halo near the Sun.

Aims. We aim to identify and characterise such merger debris using Gaia DR3 data supplemented with metallicity and chemical abundance data from LAMOST LRS and APOGEE for halo stars within 2.5 kpc from the Sun.

Methods. We utilised a single linkage-based clustering algorithm to identify over-densities in the integrals of motion space that could be due to merger debris. Combined with metallicity information and chemical abundances, we characterised these statistically significant over-densities.

Results. We find that the local stellar halo contains seven main dynamical groups, with some of them shown to be in situ and some of accreted origin, most of which are already known. We report the discovery of a new substructure, which we dubbed ED-1. In addition, we find evidence for 11 independent smaller clumps, 5 of which are new: ED-2, 3, 4, 5, and 6, and typically rather tight dynamically. We identify their narrow range of metallicities, along with their abundances when available, as well as their locations in the integrals of motion space, which are suggestive of an accreted origin.

Conclusions. The local halo contains an important amount of substructure of both in situ and accreted origins.
Direct measurements of carbon and sulfur isotope ratios in the Milky Way
Authors: Yan Y. T. , Henkel C. , Kobayashi C. , Menten K. M. , Gong Y. , Zhang J. S. , Yu H. Z. , Yang K. , Xie J. J. , Wang Y. X.
Published: January 2023

Context. Isotope abundance ratios provide a powerful tool for tracing stellar nucleosynthesis, evaluating the composition of stellar ejecta, and constraining the chemical evolution of the Milky Way.

Aims. We aim to measure the 12C/13C, 32S/34S, 32S/33S, 32S/36S, 34S/33S, 34S/36S, and 33S/36S isotope ratios across the Milky Way.

Methods. With the IRAM 30 meter telescope, we performed observations of the J = 2−1 transitions of CS, C33S, C34S, C36S, 13CS, 13C33S, and 13C34S as well as the J = 3−2 transitions of C33S, C34S, C36S, and 13CS toward a large sample of 110 high-mass star-forming regions.

Results. We measured the 12C/13C, 32S/34S, 32S/33S, 32S/36S, 34S/33S, 34S/36S, and 33S/36S abundance ratios with rare isotopologs of CS, thus avoiding significant saturation effects. With accurate distances obtained from parallax data, we confirm previously identified 12C/13C and 32S/34S gradients as a function of galactocentric distance. In the central molecular zone, 12C/13C ratios are higher than suggested by a linear fit to the disk values as a function of galactocentric radius. While 32S/34S ratios near the Galactic center and in the inner disk are similar, this is not the case for 12C/13C, when comparing central values with those near galactocentric radii of 5 kpc. As was already known, there is no 34S/33S gradient but the average ratio of 4.35 ± 0.44 derived from the J = 2−1 transition lines of C34S and C33S is well below previously reported values. A comparison between solar and local interstellar 32S/34S and 34S/33S ratios suggests that the Solar System may have been formed from gas with a particularly high 34S abundance. For the first time, we report positive gradients of 32S/33S, 34S/36S, 33S/36S, and 32S/36S in our Galaxy. The predicted 12C/13C ratios from the latest Galactic chemical-evolution models are in good agreement with our results. While 32S/34S and 32S/36S ratios show larger differences at larger galactocentric distances, 32S/33S ratios show an offset across the entire inner 12 kpc of the Milky Way.
TheGaia-ESO Survey: Preparing the ground for 4MOST and WEAVE galactic surveys
Authors: Nepal S. , Guiglion G. , de Jong R. S. , Valentini M. , Chiappini C. , Steinmetz M. , Ambrosch M. , Pancino E. , Jeffries R. D. , Bensby T. , Romano D. , Smiljanic R. , Dantas M. L. L. , Gilmore G. , Randich S. , Bayo A. , Bergemann M. , Franciosini E. , Jiménez-Esteban F. , Jofré P. , Morbidelli L. , Sacco G. G. , Tautvaišienė G. , Zaggia S.
Published: January 2023

Context.With its origin coming from several sources (Big Bang, stars, cosmic rays) and given its strong depletion during its stellar lifetime, the lithium element is of great interest as its chemical evolution in the Milky Way is not well understood at present. To help constrain stellar and galactic chemical evolution models, numerous and precise lithium abundances are necessary for a large range of evolutionary stages, metallicities, and Galactic volume.

Aims.In the age of stellar parametrization on industrial scales, spectroscopic surveys such as APOGEE, GALAH, RAVE, and LAMOST have used data-driven methods to rapidly and precisely infer stellar labels (atmospheric parameters and abundances). To prepare the ground for future spectroscopic surveys such as 4MOST and WEAVE, we aim to apply machine learning techniques to lithium measurements and analyses.

Methods.We trained a convolution neural network (CNN), couplingGaia-ESO Survey iDR6 stellar labels (Teff, log(g), [Fe/H], and A(Li)) and GIRAFFE HR15N spectra, to infer the atmospheric parameters and lithium abundances for ∼40 000 stars. The CNN architecture and accompanying notebooks are available online via GitHub.

Results.We show that the CNN properly learns the physics of the stellar labels, from relevant spectral features through a broad range of evolutionary stages and stellar parameters. The lithium feature at 6707.8 Å is successfully singled out by our CNN, among the thousands of lines in the GIRAFFE HR15N setup. Rare objects such as lithium-rich giants are found in our sample. This level of performance is achieved thanks to a meticulously built, high-quality, and homogeneous training sample.

Conclusions.The CNN approach is very well adapted for the next generations of spectroscopic surveys aimed at studying (among other elements) lithium, such as the 4MIDABLE-LR/HR (4MOST Milky Way disk and bulge low- and high-resolution) surveys. In this context, the caveats of machine-learning applications should be appropriately investigated, along with the realistic label uncertainties and upper limits for abundances.
Using photometric redshift data to improve the detection of galactic filaments with the Bisous model
Authors: Muru M. M. , Tempel E.
Published: January 2023

Context. Filament finders are limited, among other things, by the abundance of spectroscopic redshift data. This limits the sky areas and depth where we can detect the filamentary network.

Aims. As there are proportionally more photometric redshift data than spectroscopic, we aim to use data with photometric redshifts to improve and expand the areas where we can detect the large-scale structure of the Universe. The Bisous model is a filament finder that uses only the galaxy positions. We present a proof of concept, showing that the Bisous filament finder can improve the detected filamentary network with photometric redshift data.

Methods. We created mock data from the MULTIDARK-GALAXIES catalogue. Galaxies with spectroscopic redshifts were given exact positions from the simulation. Galaxies with photometric redshifts were given uncertainties along one coordinate. The errors were generated with different Gaussian distributions for different samples. We sample the photometric galaxy positions for each Bisous run based on the uncertainty distribution. In some runs, the sampled positions are closer to the true positions and produce persistent filaments; other runs produce noise, which is suppressed in the post-processing.

Results. There are three different types of samples: spectroscopic only, photometric only, and mixed samples of galaxies with photometric and spectroscopic redshifts. In photometric-only samples, the larger the uncertainty for photometric redshifts, the fewer filaments are detected, and the filaments strongly align along the line of sight. Using mixed samples improves the number of filaments detected and decreases the alignment bias of those filaments. The results are compared against the full spectroscopic sample. The recall for photometric-only samples depends heavily on the size of uncertainty and dropped close to 20%; for mixed samples, the recall stayed between 40% and 80%. The false discovery rate stayed below 5% in every sample tested in this work. Mixed samples showed better results than corresponding photometric-only or spectroscopic-only samples for every uncertainty size and number of spectroscopic galaxies in mixed samples.

Conclusions. Mixed samples of galaxies with photometric and spectroscopic redshifts help us to improve and extend the large-scale structure further than possible with only spectroscopic samples. Although the uncertainty sizes tested in this work are smaller than those for the available photometric data, upcoming surveys, such as J-PAS, will achieve sufficiently small uncertainties to be useful for large-scale structure detection.
26Al gamma rays from the Galaxy with INTEGRAL/SPI
Authors: Pleintinger Moritz M. M. , Diehl Roland , Siegert Thomas , Greiner Jochen , Krause Martin G. H.
Published: January 2023

Context.The presence of radioactive26Al at 1.8 MeV reveals an ongoing process of nucleosynthesis in the Milky Way. Diffuse emission from its decay can be measured with gamma-ray telescopes in space. The intensity, line shape, and spatial distribution of the26Al emission allow for studies of these nucleosynthesis sources. The line parameters trace massive-star feedback in the interstellar medium thanks to its 1 My lifetime.

Aims.We aim to expand upon previous studies of the26Al emission in the Milky Way, using all available gamma-ray data, including single and double events collected with SPI on INTEGRAL from 2003 until 2020.

Methods.We applied improved spectral response and background as evaluated from tracing spectral details over the entire mission. The exposure for the Galactic26Al emission was enhanced using all event types measured within SPI. We redetermined the intensity of Galactic26Al emission across the entire sky, through maximum likelihood fits of simulated and model-built sky distributions to SPI spectra for single and for double detector hits.

Results.We found an all-sky flux of (1.84±0.03)×10−3ph cm−2s−1in the 1.809 MeV line from26Al, determined via fitting to sky distributions from previous observations with COMPTEL. Significant emission from higher latitudes indicates an origin from nearby massive-star groups and superbubbles, which is also supported by a bottom-up population synthesis model. The line centroid is found at (1809.83±0.04 keV), while the line broadening from source kinematics integrated over the sky is (0.62±0.3) keV (FWHM).
The temperature dependency of Wolf–Rayet-type mass loss
Authors: Sander A. A. C. , Lefever R. R. , Poniatowski L. G. , Ramachandran V. , Sabhahit G. N. , Vink J. S.
Published: January 2023

Context. The mass loss of helium-burning stars, which are partially or completely stripped of their outer hydrogen envelope, is a catalyst of the cosmic matter cycle and decisive ingredient of massive star evolution. Yet, its theoretical fundament is only starting to emerge with major dependencies still to be uncovered.

Aims. A temperature or radius dependence is usually not included in descriptions for the mass loss of classical Wolf-Rayet (cWR) stars, despite being crucial for other hot star wind domains. We thus aim to determine whether such a dependency will also be necessary for a comprehensive description of mass loss in the cWR regime.

Methods. Sequences of dynamically consistent stellar atmosphere models were calculated with the hydrodynamic branch of the PoWR code along the temperature domain, using different choices for the luminosity, mass, and surface abundances. For the first time, we allowed nonmonotonic velocity fields when solving the hydrodynamic equation of motion. The resulting velocity structures were then interpolated for the comoving-frame radiative transfer, ensuring that the main wind characteristics were preserved.

Results. We find a strong dependence of the mass-loss rate with the temperature of the critical/sonic point which mainly reflects the different radii and resulting gravitational accelerations. Moreover, we obtain a relation between the observed effective temperature and the transformed mass-loss rate Ṁt which seems to be largely independent of the underlying stellar parameters. The relation is shifted when different density contrasts are assumed for the wind clumping. Below a characteristic value of log (Ṁt [M⊙ yr−1]) −4.5, the slope of this relation changes and the winds become transparent for He II ionizing photons.

Conclusions. The mass loss of cWR stars is a high-dimensional problem but also shows inherent scalings which can be used to obtain an approximation of the observed effective temperature. For a more realistic treatment of cWR stars and their mass loss in stellar evolution, we recommend the inclusion of a temperature dependency and ideally the calculation of hydrodynamic structure models.
The aperiodic firehose instability of counter-beaming electrons in space plasmas
Authors: Lazar M. , López R. A. , Moya P. S. , Poedts S. , Shaaban S. M.
Published: January 2023

Context.Recent studies have revealed new unstable regimes of the counter-beaming electrons specific to hot and dilute plasmas from astrophysical scenarios: an aperiodic firehose-like instability is induced for highly oblique angles of propagation relative to the magnetic field, resembling the fast growing and aperiodic mode triggered by the temperature anisotropyT∥ > T⊥(where ∥, ⊥ denote directions relative to the magnetic field).

Aims.The counter-beaming electron firehose instability is investigated here for space plasma conditions, which include not only a specific plasma parameterization but, in particular, the influence of an embedding background plasma of electrons and ions (protons).

Methods.We applied fundamental plasma kinetic theory to prescribe the unstable regimes, characterize the wave-number dispersion of the growth rates, and differentiate from the regimes of interplay with other instabilities. We also used numerical particle-in-cell (PIC) simulations to confirm the instability of these aperiodic modes, and their effects on the relaxation of counter-beaming electrons.

Results.Linear theory predicts a systematic inhibition of the (counter-)beaming electron firehose instability (BEFI) by reduction of the growth rates and the range of unstable wave-number with increasing relative density of the background electrons. To obtain finite and reasonably high values of the growth rate, the (relative) beam speed does not need to be very high (just comparable to the thermal speed), but the (counter-)beams must be dense enough, with a relative density of at least 15%–20% of the total density. Quantified in terms of the beam speed and the beta parameter, the plasma parametric conditions favorable to this instability are also markedly reduced under the influence of background electrons. Numerical simulations confirm not only that BEFI can be excited in the presence of background electrons, but also the inhibiting effect of this population, especially when this latter is cooler. In the regimes of transition to electrostatic (ES) instabilities, BEFI is still robust enough to develop as a secondary instability, after the relaxation of beams under a quick interaction with ES fluctuations.

Conclusions.To the features presented in previous studies, we can add that BEFI resembles the properties of solar wind firehose heat-flux instability triggered along the magnetic field by the anti-sunward electron strahl. However, BEFI is driven by a double (counter-beaming) electron strahl, and develops at highly oblique angles, which makes it potentially effective in the regularization and relaxation of the electron counter-beams observed in expanding coronal loops (with closed magnetic field topology) and in interplanetary shocks.
A recipe for orbital eccentricity damping in the type-I regime for low-viscosity 2D discs
Authors: Pichierri G. , Bitsch B. , Lega E.
Published: January 2023

Context. It is well known that partial and deep gap opening depends on a disc’s viscosity; however, damping formulas for orbital eccentricities have only been derived at high viscosities, ignoring partial gap opening.

Aims. In this work, we aim to obtain a simple formula to model eccentricity damping of the type-I regime in low-viscosity discs, where even small planets of a few to a few tens of Earth masses may start opening partial gaps in the gas surface density around their orbit.

Methods. We performed high-resolution, 2D, locally isothermal hydrodynamical simulations of planets with varying masses on fixed orbits in discs with varying aspect ratios and viscosities. We determined the torque and power felt by the planet to ultimately derive migration and eccentricity damping timescales.

Results. We first find a lower limit to the gap depths below which vortices appear; this happens roughly at the transition between type-I and classical type-II migration regimes. For the simulations that remain stable, we obtain a fit to the observed gap depth in the limit of vanishing eccentricities that is similar to the one currently used in the literature but accurate down to α = 3.16 × 10−5. We then record the eccentricity damping efficiency as a function of the observed gap depth and the initial eccentricity. When the planet has opened a deep enough gap such that the surface density is less than ~80% of the unperturbed disc surface density, a clear linear trend is observed independently of the planet’s eccentricity; at shallower gaps, this linear trend is preserved at low eccentricities, while it deviates to more efficient damping when e is comparable to the disc’s scale height. Both trends can be understood on theoretical grounds and are reproduced by a simple fitting formula.

Conclusions. Our combined fits for the gap depth and eccentricity damping efficiency yield a simple recipe to implement type-I eccentricity damping in N-body codes in the case of partial gap opening planets that is consistent with high-resolution 2D hydrodynamical simulations. The typical error of the final fit is of the order of a few percent, and at most ~20%, which is the error of type-I torque formulas widely used in the literature. This will allow a more self-consistent treatment of planet-disc interactions of the type-I regime for population synthesis models at low viscosities.
KiDS-Legacy calibration: Unifying shear and redshift calibration with the SKiLLS multi-band image simulations
Authors: Li Shun-Sheng , Kuijken Konrad , Hoekstra Henk , Miller Lance , Heymans Catherine , Hildebrandt Hendrik , van den Busch Jan Luca , Wright Angus H. , Yoon Mijin , Bilicki Maciej , Bravo Matías , Lagos Claudia del P.
Published: January 2023

We present SKiLLS, a suite of multi-band image simulations for the weak lensing analysis of the complete Kilo-Degree Survey (KiDS), dubbed KiDS-Legacy analysis. The resulting catalogues enable joint shear and redshift calibration, enhancing the realism and hence accuracy over previous efforts. To create a large volume of simulated galaxies with faithful properties and to a sufficient depth, we integrated cosmological simulations with high-quality imaging observations. We also improved the realism of simulated images by allowing the point spread function (PSF) to differ between CCD images, including stellar density variations and varying noise levels between pointings. Using realistic variable shear fields, we accounted for the impact of blended systems at different redshifts. Although the overall correction is minor, we found a clear redshift-bias correlation in the blending-only variable shear simulations, indicating the non-trivial impact of this higher-order blending effect. We also explored the impact of the PSF modelling errors and found a small yet noticeable effect on the shear bias. Finally, we conducted a series of sensitivity tests, including changing the input galaxy properties. We conclude that our fiducial shape measurement algorithm,lensfit, is robust within the requirements of lensing analyses with KiDS. As for future weak lensing surveys with tighter requirements, we suggest further investments in understanding the impact of blends at different redshifts, improving the PSF modelling algorithm and developing the shape measurement method to be less sensitive to the galaxy properties.
Gaia search for early-formed andesitic asteroidal crusts
Authors: Galinier M. , Delbo M. , Avdellidou C. , Galluccio L. , Marrocchi Y.
Published: January 2023

Context. Andesitic meteorites are among the oldest achondrites known to date. They record volcanic events and crust formation episodes in primordial planetesimals that took place about 4.565 Myr ago. However, no analogue for these meteorites has been found in the asteroid population to date.

Aims. We searched for spectroscopic analogues of the andesitic meteorite Erg Chech 002 in the asteroid population using the Gaia DR3 spectral dataset.

Methods. In order to identify which asteroids have the most similar spectrum to Erg Chech 002, we first determined the spectral parameters of Gaia DR3 asteroids (spectral slope and Band I depth) and compared them to the spectral parameters of different samples of the meteorite. In addition, we performed a spectral curve matching between Erg Chech 002 and Gaia DR3 asteroid data, and we compared the results of both methods.

Results. We found that 51 main-belt asteroids have a visible spectrum similar to the one of Erg Chech 002, and 91 have a spectrum similar to the space-weathered spectra of the meteorite, corresponding to 0.08% and 0.15% of the whole Gaia DR3 dataset of asteroids with spectra, respectively. The asteroids that best match the laboratory samples of the meteorite are mostly located in the inner main belt, while the objects matching the space-weathered meteorite models show slightly more scattering across the belt.

Conclusions. Despite the fact that we find asteroids that potentially match Erg Chech 002, these asteroids are extremely rare. Moreover, a visible spectrum alone is not completely diagnostic of an Erg Chech 002-like composition. Near-infrared spectra will be important to confirm (or rule out) the spectral matches between Erg Chech 002 and the candidate asteroid population.
Analysis of the first infrared spectrum of quasi-bound H2line emission in Herbig-Haro 7
Authors: Roueff E. , Burton M. G. , Geballe T. R. , Abgrall H.
Published: January 2023

Context.Highly excited molecular hydrogen (H2) has been observed in many regions of shocked molecular gas. A recently publishedK-band spectrum of Herbig-Haro 7 (HH7) contains several vibration-rotation lines of H2from highly excited energy levels that have not been detected elsewhere, including a line at 2.179 μm identified as arising from thev = 2,  J = 29 level, which lies above the dissociation limit of H2. One emission line at 2.104 μm in this spectrum was unidentified.

Aims.We aim to complete the analysis of the spectrum of HH7 by including previously missing molecular data that have been recently computed.

Methods.We re-analysed theK-band spectrum, emphasising the physics of quasi-bound upper levels that can produce infrared emission lines in theKband.

Results.We confirm the identification of the 2 − 1S(27) line at 2.1785 μm and identify the line at 2.1042 μm as due to the 1−0S(29) transition of H2, whose upper level energy is also higher than the dissociation limit. This latter identification, its column density, and the energy of its upper level further substantiate the existence of a hot thermal component at 5000 K in the HH7 environment.

Conclusions.The presence of the newly identified 1 − 0S(29) line, whose quasi-bound upper level (v = 1,J = 31) has a significant spontaneous dissociation probability, shows that dissociation of H2is occurring. The mechanism by which virtually all of the H2in levels with energies from 20 000 K to 53 000 K is maintained in local thermodynamic equilibrium at a single temperature of ∼5000 K remains to be understood.
Resolved near-UV hydrogen emission lines at 40-Myr super-Jovian protoplanet Delorme 1 (AB)b
Authors: Ringqvist Simon C. , Viswanath Gayathri , Aoyama Yuhiko , Janson Markus , Marleau Gabriel-Dominique , Brandeker Alexis
Published: January 2023

Context. Accretion at planetary-mass companions (PMCs) suggests the presence of a protoplanetary disc in the system, likely accompanied by a circumplanetary disc. High-resolution spectroscopy of accreting PMCs is very difficult due to their proximity to bright host stars. For well-separated companions, however, such spectra are feasible and they are unique windows into accretion.

Aims. We have followed up on our observations of the 40-Myr, and still accreting, circumbinary PMC Delorme 1 (AB)b. We used high-resolution spectroscopy to characterise the accretion process further by accessing the wealth of emission lines in the near-UV.

Methods. We have used the UVES spectrograph on the ESO VLT/UT2 to obtain Rλ ≈ 50 000 spectroscopy, at 3300–4520 Å, of Delorme 1 (AB)b. After separating the emission of the companion from that of the M5 low-mass binary, we performed a detailed emission-line analysis, which included planetary accretion shock modelling.

Results. We reaffirm ongoing accretion in Delorme 1 (AB)b and report the first detections in a (super-Jovian) protoplanet of resolved hydrogen line emission in the near-UV (Hγ, Hδ, Hϵ, H8, and H9). We tentatively detect H11, H12, He I, and Ca II H/K. The analysis strongly favours a planetary accretion shock with a line-luminosity-based accretion rate of Ṁ = 2 × 10−8 MJ yr−1. The lines are asymmetric and are well described by sums of narrow and broad components with different velocity shifts. The overall line shapes are best explained by a pre-shock velocity of v0 = 170 ± 30 km s−1, implying a planetary mass of MP = 13 ± 5 MJ, and number densities of n0 ≳ 1013 cm−3 or n0 ∼ 1011 cm−3. The higher density implies a small line-emitting area of ∼1% relative to the planetary surface. This favours magnetospheric accretion, a case potentially strengthened by the presence of blueshifted emission in the line profiles.

Conclusions. High-resolution spectroscopy offers the opportunity to resolve line profiles, which are crucial for studying the accretion process in depth. The super-Jovian protoplanet Delorme 1 (AB)b is still accreting at ∼40 Myr. Thus, Delorme 1 belongs to the growing family of ‘Peter Pan disc’ systems with (a) protoplanetary and/or circumplanetary disc(s) far beyond the typically assumed disc lifetimes. Further observations of this benchmark companion and its presumed disc(s) will help answer key questions about the accretion geometry in PMCs.