Imaging the Architecture of Mineral Systems and the Pathways of Ore-forming Fluids across Mongolia with Magnetotellurics

In the framework of a mineral system approach,a combination of components is required to develop a mineral system.This includes the whole-lithosphere architecture,which controls the transport of ore-forming fluids,and favorable tectonic and geodynamic processes,occurring at various spatial and temporal scales,that influence the genesis and evolution of ore-forming fluids(Huston et al.,2016;Groves et al.,2018;Davies et al.,2020).Knowledge of the deep structural framework can advance the understanding of the development of a mineral system and the emplacement of mineral deposits.Deep geophysical exploration carried out with this aim is increasingly important for targeting new ore deposits in unexplored and underexplored regions(Dentith et al.,2018;Dentith,2019).

Study of 26 Galactic Open Clusters with Extended Main-sequence Turnoffs

Recent studies indicate that some Galactic open clusters(OCs)exhibit extended main-sequence turnoff(eMSTO)in their color–magnitude diagrams(CMDs).However,the number of Galactic OCs with eMSTO structures detected so far is limited,and the reasons for their formation are still unclear.This work identifies 26 Galactic OCs with undiscovered eMSTOs and investigates the causes of these features.Stellar population types and fundamental parameters of cluster samples are acquired using CMD fitting methods.Among them,the results of 11 OCs are reliable as the observed CMDs are well-reproduced.We propose the crucial role of stellar binarity and confirm the importance of stellar rotation in reproducing eMSTO morphologies.The results also show that the impact of age spread is important,as it can adequately explain the structure of young OCs and fit the observed CMDs of intermediate-age OCs better.

Two-dimensional particle-in-cell modeling of blow-off impulse by X-ray irradiation

Space objects such as spacecraft or missiles may be exposed to intense X-rays in outer space,leading to severe damage.The reinforcement of these objects to reduce the damage caused by X-ray irradiation is a significant concern.The blow-off impulse(BOI)is a crucial physical quantity for investigating material damage induced by X-ray irradiation.However,the accurate calculation of BOI is challenging,particularly for large deformations of materials with complex configurations.In this study,we develop a novel two-dimensional particle-in-cell code,Xablation2D,to calculate BOIs under far-field X-ray irradiation.This significantly reduces the dependence of the numerical simulation on the grid shape.The reliability of this code is verified by simulation results from open-source codes,and the calculated BOIs are consistent with the experimental and analytical results.

The FRB-searching Pipeline of the Tianlai Cylinder Pathfinder Array

This paper presents the design,calibration,and survey strategy of the Fast Radio Burst(FRB)digital backend and its real-time data processing pipeline employed in the Tianlai Cylinder Pathfinder Array.The array,consisting of three parallel cylindrical reflectors and equipped with 96 dual-polarization feeds,is a radio interferometer array designed for conducting drift scans of the northern celestial semi-sphere.The FRB digital backend enables the formation of 96 digital beams,effectively covering an area of approximately 40 square degrees with the 3 dB beam.Our pipeline demonstrates the capability to conduct an automatic search of FRBs,detecting at quasi-realtime and classifying FRB candidates automatically.The current FRB searching pipeline has an overall recall rate of88%.During the commissioning phase,we successfully detected signals emitted by four well-known pulsars:PSR B0329+54,B2021+51,B0823+26,and B2020+28.We report the first discovery of an FRB by our array,designated as FRB 20220414A.We also investigate the optimal arrangement for the digitally formed beams to achieve maximum detection rate by numerical simulation.

Assessment of the Application of the Integrated Multi-Satellite Retrievals for GPM Satellite Precipitation Products for Extreme Dry and Wet Events Monitoring in Togo (2001-2019)

Togo’s economy is heavily dependent on rainfed agriculture. Therefore, anomalies in precipitation can have a significant impact on crop yields, affecting food production and security. Thus, monitoring anomalous climate conditions in Togo through the combination of precipitation satellite-based data and Standard Precipitation Index (SPI) help anticipate the development of drought scenarios or excessive rainfall, allowing farmers to adjust their strategies and minimize losses. Continuous and adequate spatial monitoring of these climate anomalies provided by satellite-based products can be central to an effective early warning system (EWS) implementation in Togo. Precipitation satellite-based products have been presented invaluable tools for assessing droughts and , offering timely and comprehensive data that supports a wide range of applications. In this study, we applied the Integrated Multi-satellite Retrievals for GPM (IMERG) rainfall product, a unified satellite global precipitation product developed by NASA, to identify and characterize the severity of dry and wet climate events in Togo during the period from 2001 to 2019. The Standard Precipitation Index (SPI), as the main index recommended by the World Meteorological Organization to monitor drought wide world, was selected as the reference index to monitor dry and wet climate events across Togo regions. The results show two distinct major climate periods in Togo in the timeframe analyzed (2001-2019), one dominated by wet events from 2008 to 2010, and a second marked by severe and extreme dry events from 2013 to 2015;MERG rainfall and SPI combination were able to capture these events consistently.

Swift XRT Analysis of Type II-P Supernova SN 2008ij

This study investigates the X-ray properties and evolution of Type II supernovae (SNe II) observed by Swift, examining variations among supernovae and exploring their X-ray characteristics over time. We present the first X-ray study of the Type IIp supernova SN 2008ij using data from the Swift X-ray mission. This investigation focuses on its spectral properties, identifying an X-ray flux of 1.20 (+0.11, −0.10) × 10−13 erg/cm2/s and a plasma temperature of 4.76 (+1.22, −0.83) keV. Our study marks an advancement in understanding SN 2008ij, providing crucial results into its X-ray emission characteristics. These results lay the groundwork for future studies of Type IIp supernovae, offering a foundation for exploring their evolutionary and physical processes.

The ALMA-QUARKS Survey.Ⅱ.The ACA 1.3 mm Continuum Source Catalog and the Assembly of Dense Gas in Massive Star-Forming Clumps

Leveraging the high resolution,sensitivity,and wide frequency coverage of the Atacama Large Millimeter/submillimeter Array(ALMA),the QUARKS survey,standing for“Querying Underlying mechanisms of massive star formation with ALMA-Resolved gas Kinematics and Structures”,is observing 139 massive starforming clumps at ALMA Band 6(λ~1.3 mm).This paper introduces the Atacama Compact Array(ACA)7 m data of the QUARKS survey,describing the ACA observations and data reduction.Combining multiwavelength data,we provide the first edition of QUARKS atlas,offering insights into the multiscale and multiphase interstellar medium in high-mass star formation.The ACA 1.3 mm catalog includes 207 continuum sources that are called ACA sources.Their gas kinetic temperatures are estimated using three formaldehyde transitions with a non-LTE radiation transfer model,and the mass and density are derived from a dust emission model.The ACA sources are massive(16–84 percentile values of 6–160 M_(⊙)),gravity-dominated(M∝R^(1.1))fragments within massive clumps,with supersonic turbulence(M>1)and embedded star-forming protoclusters.We find a linear correlation between the masses of the fragments and the massive clumps,with a ratio of 6%between the two.When considering fragments as representative of dense gas,the ratio indicates a dense gas fraction(DGF)of 6%,although with a wide scatter ranging from 1%to 10%.If we consider the QUARKS massive clumps to be what is observed at various scales,then the size-independent DGF indicates a self-similar fragmentation or collapsing mode in protocluster formation.With the ACA data over four orders of magnitude of luminosity-to-mass ratio(L/M),we find that the DGF increases significantly with L/M,which indicates clump evolutionary stage.We observed a limited fragmentation at the subclump scale,which can be explained by a dynamic global collapse process.

A Catalog of Collected Debris Disks:Properties,Classifications and Correlations between Disks and Stars/Planets

We have collected a catalog of 1095 debris disks with properties and classification(resolved,planet,gas)information.From the catalog,we defined a less biased sample with 612 objects and presented the distributions of their stellar and disk properties to search for correlations between disks and stars.We found debris disks were widely distributed from B to M-type stars while planets were mostly found around solar-type stars,gases were easier to detect around early-type stars and resolved disks were mostly distributed from A to G-type stars.The fractional luminosity dropped off with stellar age and planets were mostly found around old stars while gas-detected disks were much younger.The dust temperature of both one-belt systems and cold components in two-belt systems increased with distance while decreasing with stellar age.In addition,we defined a less biased planet sample with 211 stars with debris disks but no planets and 35 stars with debris disks and planets and found the stars with debris disks and planets had higher metallicities than stars with debris disks but no planets.Among the 35 stars with debris disks and planets,we found the stars with disks and cool Jupiters were widely distributed with age from 10 Myr to 10 Gyr and metallicity from-1.56 to 0.28 while the other three groups tended to be old(>4Gyr)and metal-rich(>-0.3).In addition,the eccentricities of cool Jupiters are distributed from 0 to 0.932,wider than the other three types of planets(<0.3).

Study of the Long-term BVR_(c)I_(c) Photometric Variability of Eight PMS Stars in the Young Open Cluster Trumpler 37

This paper reports results from our long-term BV(RI)_(c) photometric CCD observations of eight pre-main sequence stars collected from 2008 June to 2022 October.These stars are located in the young open cluster Trumpler 37,in the field of GM Cephei.The observational data indicate that all stars from our study exhibit variability in all-optical passbands,typical for young stars.In this paper,we describe and discuss the photometric behavior of the stars and the possible reasons for their variability.For two of the objects,we identified periodicity in their light variation.

LISC Catalog of Open ClustersⅢ.83 Newly Found Galactic Disk Open Clusters Using Gaia EDR3

As groups of coeval stars born from the same molecular cloud,an open cluster(OC)is an ideal laboratory for studying the structure and dynamical evolution of the Milky Way.The release of high-precision Gaia Early Data Release 3(Gaia EDR3)and modern machine-learning methods offer unprecedented opportunities to identify OCs.In this study,we extended conventional HDBSCAN(e-HDBSCAN)for searching for new OCs in Gaia EDR3.A pipeline was developed based on the parallel computing technique to blindly search for OCs from Gaia EDR3within Galactic latitudes∣b∣<25°.As a result,we obtained 3787 star clusters,of which 83 new OCs were reported after cross-match and visual inspection.At the same time,the main star cluster parameters are estimated by color-magnitude diagram fitting.The study significantly increases the sample size and physical parameters of OCs in the catalog of OCs.It shows the incompleteness of the census of OCs across our Galaxy.

Electron beam pumping improves the conversion efficiency of low-frequency photons radiated by perovskite quantum dots

This research argues that using an electron beam with high kinetic energy to pump perovskite quantum dots can significantly boost the efficiency of the low-frequency photon radiation conversion.Firstly,we measure the random lasing threshold and luminescence threshold of CsPbX_(3)films pumped by an electron beam.Then,we simulate the spatial distribution of the electron beams in CsPbX_(3)films.Combined with the above data,a low-frequency photon radiation conversion model based on the electron pumped perovskite quantum dots is presented.This could be a way to create a terahertz source with a high-power output or to multiply the terahertz power.

A Protocol for Conversion of Path-Spin to Spin-Spin Quantum Entanglement

The present model deals with a protocol which involves the generation and conversion of entanglement from pathspin(P-S)hybrid entanglement associated with half-spin particle to spin-spin(S-S)interparticle entanglement.This protocol finds its applications in quantum information processing via a series of operations which include a beam splitter,spin flipper,spin measurement,classical channel,unitary transformations.Finally,it leads to two particles having completely entangled spin variables,without any requirement of any simultaneous operation on the two particles.

Source Mechanisms of Recent Earthquakes in Southern Saudi Arabia: Detecting of New Seismic Sources

Recently in 2020, in southern Saudi Arabia three felt earthquakes occurred in Asir region, in the Khamis Mushait, Ahad Rafidah, and AL-Shuqiq area, of magnitude 3.45, 3.1, and 3.5, respectively. The most interesting event was the earthquake that occurred in Khamis Mushait area, along a lake formed behind the Tadhah Dam (~7 km), fearing any damage to the dam’s body and the consequent destruction. Moment tensors for each event were computed for determining fault plane solutions, seismic moment, moment magnitude (Mw) and the CLVD ratio. In addition, the frequency contents in the waveforms of each event were identified. The obtained focal mechanisms represent different styles of faulting, normal movement with strike slip and strike slip with reverse. These tectonic movements on faults parallel to the Red Sea refer to the tensional forces due to the Red Sea rift system. These events occurred due to a natural tectonic movement, with considering the Khamis Mushait event as an induced event because of the lake behind the Dam. Many previous seismic hazard assessment studies have been conducted in southern Saudi Arabia without considering these recent seismic sources. Thus, our study provides new information related to detecting of new active seismic sources, which contributes to updating studies of seismic risk assessment in this region. In addition, our study pushes us to establish other additional seismic stations around these new seismic sources. This in turn will play a pivotal role in controlling seismic sources and then reassessing the seismic hazard in southern Saudi Arabia.

Curupira V1.0: Joint Inversion of VES and TEM for Environmental and Mass Movements Studies

An innovative inversion code, named “Curupira v1.0”, has been developed using Matlab to determine the vertical distribution of resistivity beneath the subsoil. The program integrates Vertical Electrical Sounding (VES), successful in shallow subsurface exploration and Time Domain Electromagnetic (TEM) techniques, better suited for deeper exploration, both of which are widely employed in geophysical exploration. These methodologies involve calculating subsurface resistivity through appropriate inversion processes. To address the ill-posed nature of inverse problems in geophysics, a joint inversion scheme combining VES and TEM data has been incorporated into Curupira v1.0. The software has been tested on both synthetic and real-world data, the latter of which was acquired from the Parana sedimentary basin which we summarise here. The results indicate that the joint inversion of VES and TEM techniques offers improved recovery of simulated models and demonstrates significant potential for hydrogeological studies.

BSEC Method for Unveiling Open Clusters and its Application to Gaia DR3:83 New Clusters

Open clusters(OCs) are common in the Milky Way, but most of them remain undiscovered. There are numerous techniques, including some machine-learning algorithms, available for the exploration of OCs. However, each method has its limitations and therefore, different approaches to discovering OCs hold significant values. We develop a comprehensive approach method to automatically explore the data space and identify potential OC candidates with relatively reliable membership determination. This approach combines the techniques of Hierarchical Density-Based Spatial Clustering of Applications with Noise, Gaussian mixture model, and a novel cluster member identification technique, color excess constraint. The new method exhibits efficiency in detecting OCs while ensuring precise determination of cluster memberships. Because the main feature of this technique is to add an extra constraint(EC) for the members of cluster candidates using the homogeneity of color excess,compared to typical blind search codes, it is called Blind Search-Extra Constraint(BSEC) method. It is successfully applied to the Gaia Data Release 3, and 83 new OCs are found, whose color–magnitude diagrams(CMDs) are fitted well to the isochrones. In addition, this study reports 621 new OC candidates with discernible main sequence or red giant branch. It is shown that BSEC technique can discard some false negatives of previous works, which takes about three percentage of known clusters. It shows that as an EC, the color excess(or twocolor) constraint is useful for removing fake cluster member stars from the clusters that are identified from the positions and proper motions of stars, and getting more precise CMDs, when differential reddening of member stars of a cluster is not large(e.g., ΔE(G_(BP)-G_(RP)) < 0.5 mag). It makes the CMDs of 15% clusters clearer(in particular for the region near turnoff) and therefore is helpful for CMD and stellar population studies. Our result suggests that the color excess constraint is more appropriate for clusters with small differential reddening, such as globular clusters or older OCs, and clusters that the distances of member stars cannot be determined accurately.

Efficient PbS quantum dots tandem solar cells through compatible interconnection layer

Lead sulfide quantum dots(PbS QDs) hold unique characteristics, including bandgap tunability, solutionprocessability etc., which make them highly applicable in tandem solar cells(TSCs). In all QD TSCs, its efficiency lags much behind to their single junction counterparts due to the deficient interconnection layer(ICL) and defective subcells. To improve TSCs performance, we developed three kinds of ICL structures based on 1.34 and 0.96 e V PbS QDs subcells. The control, 1,2-ethanedithiol capped PbS QDs(PbS-EDT)/Au/tin dioxide(SnO_(2))/zinc oxide(Zn O), utilized SnO_(2) layer to obtain high surface compactness.However, its energy level mismatch causes incomplete recombination. Bypassing it, the second ICL(PbS-EDT/Au/Zn O) removed SnO_(2) and boosted the power conversion efficiency(PCE) from 5.75% to 8.69%. In the third ICL(PbS-EDT/poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine](PTAA)/Au/Zn O), a thin layer of PTAA can effectively fill fissures on the surface of PbS-EDT and also protect the front cells from solvent penetration. This TSC obtained a PCE of 9.49% with an open circuit voltage of 0.91 V, a short circuit current density of 15.47 m A/cm~2, and a fill factor of 67.7%. To the best of our knowledge, this was the highest PCE achieved by all PbS QD TSCs reported to date. These TSCs maintained stable performance for a long working time under ambient conditions.

Preparation for CSST:Star-galaxy Classification using a Rotationally Invariant Supervised Machine Learning Method

Most existing star-galaxy classifiers depend on the reduced information from catalogs,necessitating careful data processing and feature extraction.In this study,we employ a supervised machine learning method(GoogLeNet)to automatically classify stars and galaxies in the COSMOS field.Unlike traditional machine learning methods,we introduce several preprocessing techniques,including noise reduction and the unwrapping of denoised images in polar coordinates,applied to our carefully selected samples of stars and galaxies.By dividing the selected samples into training and validation sets in an 8:2 ratio,we evaluate the performance of the GoogLeNet model in distinguishing between stars and galaxies.The results indicate that the GoogLeNet model is highly effective,achieving accuracies of 99.6% and 99.9% for stars and galaxies,respectively.Furthermore,by comparing the results with and without preprocessing,we find that preprocessing can significantly improve classification accuracy(by approximately 2.0% to 6.0%)when the images are rotated.In preparation for the future launch of the China Space Station Telescope(CSST),we also evaluate the performance of the GoogLeNet model on the CSST simulation data.These results demonstrate a high level of accuracy(approximately 99.8%),indicating that this model can be effectively utilized for future observations with the CSST.

The ALMA-QUARKS Survey.Ⅰ.Survey Description and Data Reduction

This paper presents an overview of the QUARKS survey,which stands for Querying Underlying mechanisms of massive star formation with ALMA-Resolved gas Kinematics and Structures."The QUARKS survey is observing139 massive clumps covered by 156 pointings at Atacama Large Millimeter/submillimeter Array(ALMA)Band 6(λ~1.3 mm).In conjunction with data obtained from the ALMA-ATOMS survey at Band 3(λ~3 mm),QUARKS aims to carry out an unbiased statistical investigation of massive star formation process within protoclusters down to a scale of 1000 au.This overview paper describes the observations and data reduction of the QUARKS survey,and gives a first look at an exemplar source,the mini-starburst Sgr B2(M).The wide-b and width(7.5 GHz)and high-angular-resolution(~0."3)observations of the QUARKS survey allow for the resolution of much more compact cores than those could be done by the ATOMS survey,and to detect previously unrevealed fainter filamentary structures.The spectral windows cover transitions of species including CO,SO,N_(2)D^(+),SiO,H_(30)α,H_(2)CO,CH_(3)CN,and many other complex organic molecules,tracing gas components with different temperatures and spatial extents.QUARKS aims to deepen our understanding of several scientific topics of massive star formation,such as the mass transport within protoclusters by(hub-)filamentary structures,the existence of massive starless cores,the physical and chemical properties of dense cores within protoclusters,and the feedback from already formed high-mass young protostars.

Preface: Frontiers in Astrophysics(Ⅱ)——A special issue dedicated to the 20th anniversary of RAA(2001–2020)

On the arrival of the 20 th anniversary of the journal,Research in Astronomy and Astrophysics(RAA),we see rapid progress in the frontiers of astronomy and astrophysics.To celebrate the birth and growth of RAA,a special issue consisting of 11 invited reviews from more than 30 authors,mainly from China,has been organized.This is the second volume of the special issues entitled Frontiers in Astrophysics published in RAA.The publication aims at evaluating the current status and key progress in some frontier areas of astronomy and astrophysics with a spirit of guiding future studies.

Geochemical and stable isotopic studies of Gulf of Suez’s hot springs,Egypt

The Gulf of Suez region is one of the most interesting geothermal areas in Egypt because of the high temperatures of its springs.The eastern and western shores of the Gulf of Suez are characterized by superficial thermal manifestations including a cluster of hot springs with varied temperatures.Variations of deuterium and oxygen-18 concentrations in thermal waters have been used to aid in describing the source of recharge in the Gulf of Suez hot springs.Isotope and geochemical data for the Gulf of Suez thermal waters suggest that recharge to the hot springs may not be entirely from the Gulf of Suez water,but possibly from the meteoric water that comes from areas of higher altitude surrounding the hot springs.