Ultraviolet Data Research Articles

Development of empirical models for calculating global and diffuse erythemal weighted solar ultraviolet radiation under clear sky conditions in Thailand

This study introduced semi-empirical models for calculating hourly global and diffuse erythemal weighted ultraviolet (EUV) solar radiation under clear sky conditions in Thailand. To develop these models, global and diffuse erythemal ultraviolet data collected over a decade (2011–2020) from four solar monitoring stations situated in the main regions of Thailand were used. The data was classified into two groups. The first group (2011–2018) was used for modeling, while the second group (2019–2020) was reserved for model validation. The global and diffuse EUV radiation models revolve around semi-empirical functions. These functions express both types of EUV radiation in terms of normalized variables, specifically the total ozone column, aerosol optical depth, and air mass. To assess the accuracy of the proposed models, their outputs for hourly global and diffuse EUV radiation were calculated at the four monitoring stations. These outputs were then compared against actual measurements to validate the effectiveness of the models. The evaluation revealed a root mean square difference of 15.8% for global EUV radiation and 14.9% for diffuse EUV radiation when compared to the mean measured values.

Exploring the Central Region of NGC 1365 in the Ultraviolet Domain

Active galactic nuclei (AGN) feedback and its impact on their host galaxies are critical to our understanding of galaxy evolution. Here, we present a combined analysis of new high resolution ultraviolet (UV) data from the Ultraviolet Imaging Telescope (UVIT) on AstroSat and archival optical spectroscopic data from the Very Large Telescope/MUSE, for the Seyfert galaxy, NGC 1365. Concentrating on the central 5 kpc region, the UVIT images in the far- and near-UV show bright star-forming knots in the circumnuclear ring as well as a faint central source. After correcting for extinction, we found the star formation rate (SFR) surface density of the circumnuclear 2 kpc ring to be similar to other starbursts, despite the presence of an AGN outflow, as seen in [O iii] 5007 Å. On the other hand, we found fainter UV and thus lower SFR in the direction southeast of the AGN relative to northwest in agreement with observations at other wavelengths from JWST and Atacama Large Millimeter/submillimeter Array. The AGN outflow velocity is found to be lesser than the escape velocity, suggesting that the outflowing gas will rain back into the galaxy. The deep UV data have also revealed diffuse UV emission in the direction of the AGN outflow. By combining [O iii] and UV data, we found the diffuse emission to be of AGN origin.

Microwave-Assisted, Preparation, Characterization, and Biological Activities of Schiff Bases Derived from 4-Aminoantipyrine with Acetonyl Acetone for Some New Rare-Earth Metals

Five new lanthanide complexes based on azomethine (Schiff bases) ligands have been synthesized, including La, Nd, Er, Gd, and Dy. Complexes were synthesized using the azomethine Schiff bases resulting from condensation reactions between 4-aminoantipyrine and acetonylacetone. The structural characteristics of azomethine obtained are characterized quantitatively and qualitatively through various techniques, including elemental analyses, magnetic susceptibility measurement, molar conductivity, infrared, ultraviolet absorption, GC-mass, and 1H- and 13C-NMR spectroscopy studies. The structural characteristics of Ln+3 complexes indicate that the complexes possess a composition of a specific type. Based on the elemental analyses, magnetic susceptibility measurement, molar conductivity, and ultraviolet absorption spectroscopy data, it can be inferred that the central metal ion is surrounded by a coordination number of 10, the general formula of [Ln(L)2(NO3)]·nNO3nH2O. The physical measurements confirmed that the synthesized complexes exhibit non-electrolyte behavior and paramagnetic properties. The antibacterial activity of the compounds was assessed in vitro against 4 pathogenic strains: E. coli, S. aureus, K. pneumoniae, and S. mutans. The evaluation was conducted using the agar disc spreading method. The results demonstrated that certain complexes exhibited significant antibacterial efficacy in comparison to the biological activity of the ligand.

An ultraviolet light data logger for studies of organismal ecology and physiology

Abstract Monitoring environmental conditions over time is essential for understanding how species regulate those conditions to satisfy their physiological needs. Variation in ultraviolet (UV) light exposure, for instance, is crucial for numerous taxa, influencing behaviour as well as essential physiological processes like vitamin D3 synthesis. Yet, despite these considerations, no commercially available data loggers exist to record UV exposures over time, preventing inquiry into this important but neglected fitness demand. To overcome this challenge, I designed the first UV data logger, custom built on the open‐source Arduino platform. This device logs UV exposures (in voltage or converted to UV index) and date‐time information for each UV reading, at user‐defined intervals. The integration of a low‐power timer into the assembly, and its weather‐resistant housing, enables long‐term use (at least several months). The cost of one device (including housing) is under £45/$55 USD. Calibration and performance tests reveal that this device is reliable under various weather conditions and produces accurate UV readings under both artificial lighting and sunlight. Both the device and its customised housing can be easily replicated and expanded upon (e.g. inclusion of additional sensors). Overall, this device represents a crucial first step in our ability to better characterise UV exposure patterns in habitats for physiological ecology studies. Exposure to UV light is adaptive for many types of organisms, both in the wild and in captivity (e.g. zoos and private hobbyists), and so I expect a broad array of scientific and public users alike to benefit from using this device.

Chemical abundances along the quasar main sequence

Context. The main sequence of quasars has emerged as a powerful tool for organizing the observational and physical characteristics of type-1 active galactic nuclei (AGNs). Aims. In this study, we present a comprehensive analysis of the metallicity of the gas in the broad-line region, incorporating both new data and previously published findings, to assess the presence of any trend along the main sequence. Methods. We performed a multicomponent analysis on the strongest ultraviolet (UV) and optical emission lines for a sample of 13 radio quiet quasars in the 0.009 ≤ z ≤ 0.472 redshift range, selected based on the availability of multiwavelength data. We employed UV and optical data obtained from the Hubble Space Telescope (mainly from the Cosmic Origins Spectrograph and Faint Object Spectrograph) and several ground-based observatories, respectively. We then measured ten diagnostic ratios and compared them with the prediction of CLOUDY photoionization simulations, identifying the closest photoionization solution to the data. Results. Our investigation reveals a consistent pattern along the main sequence. We observe a systematic progression in metallicity, ranging from subsolar values to metallicity levels several times higher than solar values. Conclusions. These findings underscore the fundamental role of metallicity in correlating with the main sequence of quasars. Extreme metallicity values, at least several dozen times the solar metallicity, are confirmed in low-z AGNs radiating at a high Eddington ratio, although the origin of the extreme enrichment remains open to debate.

Chemical crosslinking extends and complements UV crosslinking in analysis of RNA/DNA nucleic acid-protein interaction sites by mass spectrometry.

UV (ultra-violet) crosslinking with mass spectrometry (XL-MS) has been established for identifying RNA-and DNA-binding proteins along with their domains and amino acids involved. Here, we explore chemical XL-MS for RNA-protein, DNA-protein, and nucleotide-protein complexes in vitro and in vivo . We introduce a specialized nucleotide-protein-crosslink search engine, NuXL, for robust and fast identification of such crosslinks at amino acid resolution. Chemical XL-MS complements UV XL-MS by generating different crosslink species, increasing crosslinked protein yields in vivo almost four-fold and thus it expands the structural information accessible via XL-MS. Our workflow facilitates integrative structural modelling of nucleic acid-protein complexes and adds spatial information to the described RNA-binding properties of enzymes, for which crosslinking sites are often observed close to their cofactor-binding domains. In vivo UV and chemical XL-MS data from E. coli cells analysed by NuXL establish a comprehensive nucleic acid-protein crosslink inventory with crosslink sites at amino acid level for more than 1500 proteins. Our new workflow combined with the dedicated NuXL search engine identified RNA crosslinks that cover most RNA-binding proteins, with DNA and RNA crosslinks detected in transcriptional repressors and activators.

Ultraviolet visible spectral water chemical oxygen demand detection method based on two deep neural network model

Water resources are precious resources around the world, but pollution is becoming increasingly severe. While the degree of damage to water caused by organic pollutants is reflected by chemical oxygen demand, which is also an important indicator for hydrological monitoring. Therefore, accurate measurement of chemical oxygen demand is necessary. The rapid development of water quality detection by ultraviolet visible spectrum analysis as an efficient, convenient, and pollution-free new water quality detection method has been achieved. When we were processing ultraviolet visible spectral absorbance data, various environmental factors can affect the chemical oxygen demand light absorption value, thus affecting the accuracy of detection. So there are some goals, such as more comprehensively extracting the feature wavelength and reducing the interference to achieve better detection results. It is expected that the model can be applied to a portable water quality detection device. It is necessary to consider detection time, reduce model training parameters, and improve detection speed. Therefore, this article proposes Competitive Adaptive Weighted Sampling-Convolutional Neural Network-Long Short-Term Memory and Competitive Adaptive Weighted Sampling-Convolutional Long Short-Term Memory models for detecting chemical oxygen demand in water. To verify the effectiveness of the proposed model, the model was trained on the experimental dataset and the detection results of all models involved in the article were compared. It can be confirmed that the application of these two proposed algorithms results in less detection time and higher accuracy in concentration detection.

The Ultraviolet Luminosity Function at 0.6 < z < 1 from UVCANDELS

UVCANDELS is a Hubble Space Telescope Cycle-26 Treasury Program awarded 164 orbits of primary ultraviolet (UV) F275W imaging and coordinated parallel optical F435W imaging in four CANDELS fields—GOODS-N, GOODS-S, EGS, and COSMOS—covering a total area of ∼426 arcmin2. This is ∼2.7 times larger than the area covered by previous deep-field space UV data combined, reaching a depth of about 27 and 28 ABmag (5σ in 0.”2 apertures) for F275W and F435W, respectively. Along with new photometric catalogs, we present an analysis of the rest-frame UV luminosity function (LF), relying on our UV-optimized aperture photometry method, yielding a factor of 1.5 increase over H-isophot aperture photometry in the signal-to-noise ratios of galaxies in our F275W imaging. Using well-tested photometric redshift measurements, we identify 5810 galaxies at redshifts 0.6 < z < 1, down to an absolute magnitude of M UV = −14.2. In order to minimize the effect of uncertainties in estimating the completeness function, especially at the faint end, we restrict our analysis to sources above 30% completeness, which provides a final sample of 4726 galaxies at −21.5 < M UV < −15.5. We performed a maximum likelihood estimate to derive the best-fit parameters of the UV LF. We report a best-fit faint-end slope of α=−1.359−0.041+0.041 at z ∼ 0.8. Creating subsamples at z ∼ 0.7 and z ∼ 0.9, we observe a possible evolution of α with redshift. The unobscured UV luminosity density at M UV < −10 is derived as ρUV=1.339−0.030+0.027(×1026ergs−1Hz−1Mpc−3) using our best-fit LF parameters. The new F275W and F435 photometric catalogs from UVCANDELS have been made publicly available on the Barbara A. Mikulski Archive for Space Telescopes.

Light-curve Structure and Hα Line Formation in the Tidal Disruption Event AT 2019azh

AT 2019azh is a H+He tidal disruption event (TDE) with one of the most extensive ultraviolet and optical data sets available to date. We present our photometric and spectroscopic observations of this event starting several weeks before and out to approximately 2 yr after the g-band's peak brightness and combine them with public photometric data. This extensive data set robustly reveals a change in the light-curve slope and a possible bump in the rising light curve of a TDE for the first time, which may indicate more than one dominant emission mechanism contributing to the pre-peak light curve. Indeed, we find that the MOSFiT-derived parameters of AT 2019azh, which assume reprocessed accretion as the sole source of emission, are not entirely self-consistent. We further confirm the relation seen in previous TDEs whereby the redder emission peaks later than the bluer emission. The post-peak bolometric light curve of AT 2019azh is better described by an exponential decline than by the canonical t −5/3 (and in fact any) power-law decline. We find a possible mid-infrared excess around the peak optical luminosity, but cannot determine its origin. In addition, we provide the earliest measurements of the Hα emission-line evolution and find no significant time delay between the peak of the V-band light curve and that of the Hα luminosity. These results can be used to constrain future models of TDE line formation and emission mechanisms in general. More pre-peak 1–2 days cadence observations of TDEs are required to determine whether the characteristics observed here are common among TDEs. More importantly, detailed emission models are needed to fully exploit such observations for understanding the emission physics of TDEs.

Origin of extended main-sequence turn-off in open cluster NGC 2355

ABSTRACT The presence of extended Main-Sequence Turn-Off (eMSTO) in the open clusters has been attributed to various factors, such as spread in rotation rates, binary stars, and dust-like extinction from stellar excretion discs. We present a comprehensive analysis of the eMSTO in the open cluster NGC 2355. Using spectra from the Gaia–European Southern Observatory (ESO) archives, we find that the stars in the red part of the eMSTO have a higher mean v sin i value of 135.3 $\pm$ 4.6 km s$^{-1}$ compared to the stars in the blue part that have an average v sin i equal to 81.3 $\pm$ 5.6 km s$^{-1}$. This suggests that the eMSTO in NGC 2355 is possibly caused by the spread in rotation rates of stars. We do not find any substantial evidence of the dust-like extinction from the eMSTO stars using ultraviolet data from the Swift survey. The estimated synchronization time for low-mass ratio close binaries in the blue part of the eMSTO suggests that they would be mostly slow-rotating if present. However, the stars in the blue part of the eMSTO are preferentially located in the outer region of the cluster indicating that they may lack low-mass ratio close binaries. The spread in rotation rates of eMSTO stars in NGC 2355 is most likely caused by the star-disc interaction mechanism. The stars in the lower main sequence beyond the eMSTO region of NGC 2355 are slow rotating (mean v sin i = 26.5 $\pm$ 1.3 km s$^{-1}$) possibly due to the magnetic braking of their rotations.

UV Cooling via O VI Emission in the Superwind of M82 Observed with the Far Ultraviolet Spectroscopic Explorer (FUSE)

We examined archival Far Ultraviolet Spectroscopic Explorer data to search for far-ultraviolet emission lines in the starburst galaxy M82. The observations were made in an outflow region that extends beyond the galactic disk. We found the O vi λ λ 1032, 1038 emission lines from the galaxy’s southern outflow region. The O vi lines suggest that the outflowing warm-hot gas is undergoing radiative cooling. We measured a radial velocity of ∼420 km s−1 from the O vi lines, which is faster than the velocity seen in Hα observations. The O vi λ1038 emission line seems to be blended with the C ii λ1037 emission line, which has a radial velocity of ∼300 km s−1, similar to what is observed in Hα observations. The outflow medium of M82 appears to be composed of gas in multiple phases with varying temperatures and kinematics. Future spectroscopic observations in high energy regimes covering a wider spatial area are necessary to understand better the properties of the warm-hot gas medium in the outflow.

Filling data gaps in long-term solar UV monitoring by statistical imputation methods

Knowledge of long-term time trends of solar ultraviolet (UV) radiation on ground level is of high scientific interest. For this purpose, precise measurements over a long time are necessary. One of the challenges solar UV monitoring faces is the permanent and gap-free data collection over several decades. Data gaps hamper the formation and comparison of monthly or annual means, and, in the worst case, lead to incorrect conclusions in further data evaluation and trend analysis of UV data. For estimating data to fill gaps in long-term UV data series (daily radiant exposure and highest daily irradiance), we developed three statistical imputation methods: a model-based imputation, considering actual local solar radiation conditions using predictors correlated to the local UV values in an empirical model; an average-based imputation based on a statistical approach of averaging available local UV measurement data without predictors; and a mixture of these two imputation methods. A detailed validation demonstrates the superiority of the model-based imputation method. The combined method can be considered the best one in practice. Furthermore, it has been shown that the model-based imputation method can be used as an useful tool to identify systematic errors at and between calibration steps in long-term erythemal UV data series.

Relationship of regional ultraviolet index data with rash and systemic disease activity in youth with childhood-onset systemic lupus: results from the Childhood Arthritis and Rheumatology Research Alliance Registry

ObjectiveTo investigate the association between ultraviolet light index (UVI), as a marker for UV exposure, and seasonality with rash and systemic disease activity in youth with childhood-onset systemic lupus (cSLE) from the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry.MethodsWe reviewed data on rash and disease activity from Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2 K) scores from cSLE CARRA Registry participants with visits between 2010 and 2019 and obtained zipcode level UVI data from the National Oceanic and Atmospheric Administration (NOAA). Our main exposures were UVI and season during the month of visit and one month prior to visit. We used mixed-effects logistic regression models to examine associations between regional UVI (by zipcode)/season and odds of rash and severe SLEDAI-2 K score (≥ 5 vs. 0–4), adjusting for age, sex, race and income.ResultsAmong 1222 participants, with a mean of 2.3 visits per participant, 437 visits (15%) had rash and 860 (30%) had SLEDAI-2 K score ≥ 5. There were no associations between UVI during the month prior to visit or the month of the visit and odds of rash or elevated systemic activity. However, fall season was associated with increased odds of rash (OR = 1.59, p = 0.04), but not increased disease activity.ConclusionThis study found no association between UVI and rash or UVI and disease activity. However, further studies directly measuring UV exposure and accounting for patient-level protective behavioral measures may help to better understand the complex relationship between sun exposure and SLE disease activity.

SN 2020zbf: A fast-rising hydrogen-poor superluminous supernova with strong carbon lines

SN 2020zbf is a hydrogen-poor superluminous supernova (SLSN) at z = 0.1947 that shows conspicuous C II features at early times, in contrast to the majority of H-poor SLSNe. Its peak magnitude is Mg = −21.2 mag and its rise time (≲26.4 days from first light) places SN 2020zbf among the fastest rising type I SLSNe. We used spectra taken from ultraviolet (UV) to near-infrared wavelengths to identify spectral features. We paid particular attention to the C II lines as they present distinctive characteristics when compared to other events. We also analyzed UV and optical photometric data and modeled the light curves considering three different powering mechanisms: radioactive decay of 56Ni, magnetar spin-down, and circumstellar medium (CSM) interaction. The spectra of SN 2020zbf match the model spectra of a C-rich low-mass magnetar-powered supernova model well. This is consistent with our light curve modeling, which supports a magnetar-powered event with an ejecta mass Mej = 1.5 M⊙. However, we cannot discard the CSM-interaction model as it may also reproduce the observed features. The interaction with H-poor, carbon-oxygen CSM near peak light could explain the presence of C II emission lines. A short plateau in the light curve around 35–45 days after peak, in combination with the presence of an emission line at 6580 Å, can also be interpreted as being due to a late interaction with an extended H-rich CSM. Both the magnetar and CSM-interaction models of SN 2020zbf indicate that the progenitor mass at the time of explosion is between 2 and 5 M⊙. Modeling the spectral energy distribution of the host galaxy reveals a host mass of 108.7 M⊙, a star formation rate of 0.24−0.12+0.41 M⊙ yr−1, and a metallicity of ∼0.4 Z⊙.

Genomic and Metabolomic Analyses of Nocardiopsis maritima YSL2 as the Mycorrhizosphere Bacterium of Suaeda maritima (L.) Dumort.

Nine bacteria were isolated from the episphere of Suaeda maritima (L.) Dumort. Among them, the bacterial strain YSL2 displayed the highest antimicrobial activity on agar plates and exhibited significant novelty compared with other bacteria based on 16S rRNA analysis. Consequently, Nocardiopsis maritima YSL2T was subjected to phenotypic characterization and whole-genome sequencing. Phylogenetic analysis revealed its close association with Nocardiopsis aegyptia SNG49T. Furthermore, genomic analysis of strain YSL2T revealed the presence of various gene clusters, indicating its potential for producing antimicrobial secondary metabolites. Upon cultivation on a large scale, maritiamides A and B (1 and 2) were isolated and characterized as cyclic hexapeptides based on nuclear magnetic resonance, ultraviolet, infrared, and mass spectrometric data. The absolute configurations of the amino acid residues in the maritiamides were determined through chiral derivatization, utilizing FDAA and GITC. Maritiamides 1 and 2 exhibited promising antibacterial activities against Staphylococcus epidermidis and weakly inhibited the growth of Escherichia coli and Pseudomonas fluorescens.

Extraction of Nano Hydroxyapatite from Eggshell and Characterization for Biomedical Applications

Because of the exceptional qualities, nano-hydroxyapatites, or n-HA, are excellent materials for diverse applications. It is simple and convenient to synthesize from various natural ingredients. The synthesis of n-HA from eggshells, a typical domestic waste product in the neighborhood, was the primary goal of this study project. This synthesis of n-HA was performed using ammonia and orthophosphoric acid as chemical reagents. The synthesized n-HA have been characterized by UV (Ultraviolet), FTIR (Fourier Transformed Infrared Spectroscopy), SEM (Scanning Electron Microscopy), TEM (Transmission Electron Microscopy), and XRD (X-ray diffraction) analysis. The peak formed by the UV analysis verified the successful formation of n-HA in the solution. The bandgap has been determined through additional research on the UV data. The SEM and TEM images show the size and form of the synthesized n-HA. Based on TEM observations, the synthesized n-HA has a size in the range of 10 to 40 nm. The peak ensures the n-HA’s crystallinity that the XRD analysis produced. The obtained crystallinity was 74%.

Spatial mapping of indoor air quality in a light metro system using the geographic information system method

Abstract It is known that one of the greatest problems of developed countries in the twenty-first century is traffic. For this reason, engineers have searched for alternative solutions to the problem of traffic. One such solution is the construction and utilization of rail systems instead of main roads. From an engineering perspective, rail systems can be divided into three groups: metro, light metro, and tram systems. Light metro systems, which are a form of public transportation, are not directly inside the traffic. Their most important advantages include the fact that they do not release combustion products such as CO, and metro and light metro systems may be considered environmentally friendly based solely on their electricity consumption. In this study, measurements of parameters affecting indoor air quality were made inside light metro cars and in and around light metro stations belonging to the light metro system of the Metropolitan Municipality of Antalya, known as the tourism capital of Turkey. In February and March 2021, when the COVID-19 pandemic was first registered in Turkey, particulate matter (PM), temperature, and relative humidity measurements were made for testing indoor and outside air quality. Moreover, as outside air parameters, outside temperature, outside relative humidity, CO, normalized difference vegetation index, and ultraviolet aerosol index data were obtained from the General Directorate of Meteorology of Turkey. The measurement results were analyzed using the inverse distance weighting method in the geographic information system. Based on the results of the analyses, spatial maps were created for indoor and outside air quality parameters in the light metro system. Using these maps, the effects of passenger density and environmental factors both inside the metro cars and at the metro stations on indoor air quality were identified. In addition, the spread of the SARS-CoV-2 virus in the COVID-19 period was analyzed using spatial maps of the PM0.3 and PM0.5 parameters. It is believed that the results of this study will set an example for further indoor air quality studies worldwide, and this study is unique in that it employed a method that is used particularly in survey and geomatics engineering for analyzing indoor air quality in light metro systems.

Attenuation proxy hidden in surface brightness – colour diagrams

Aims. Large future sky surveys, such as the Legacy Survey of Space and Time (LSST), will provide optical photometry for billions of objects. Reliable estimation of the physical properties of galaxies requires information about dust attenuation, which is usually derived from ultraviolet (UV) and infrared (IR) data. This paper aims to construct a proxy for the far-UV (FUV) attenuation (AFUVp) from the optical data alone, enabling the rapid estimation of the star formation rate (SFR) for galaxies that lack UV or IR data. This will accelerate and improve the estimation of key physical properties of billions of LSST–like observed galaxies (observed in the optical bands only). Methods. To mimic LSST observations, we used the deep panchromatic optical coverage of the Sloan Digital Sky Survey (SDSS) Photometric Catalogue, Data Release 12, complemented by the estimated physical properties for the SDSS galaxies from the GALEX-SDSS-WISE Legacy Catalog (GSWLC) and inclination information obtained from the SDSS Data Release 7. We restricted our sample to the 0.025–0.1 spectroscopic redshift range and investigated relations among surface brightness, colours, and dust attenuation in the FUV range for star-forming galaxies obtained from the spectral energy distribution (SED). Results. Dust attenuation is best correlated with colour measured between u and r bands (u − r) and the surface brightness in the u band (μu). We provide a dust attenuation proxy for galaxies on the star-forming main sequence. This relation can be used for the LSST or any other type of broadband optical survey. The mean ratio between the catalogue values of SFRs and those estimated using optical-only SDSS data with the AFUVp prior calculated as ΔSFR = log(SFRthis work/SFRGSWLC) is found to be less than 0.1 dex, while runs without priors result in an SFR overestimation larger than 0.3 dex. The presence or absence of the AFUVp has a negligible influence on the stellar mass (Mstar) estimation (with ΔMstar in the range from 0 to −0.15 dex). Conclusions. We note that AFUVp is reliable for low-redshift main sequence galaxies. Forthcoming deep optical observations of the LSST Deep Drilling Fields, which also have multi-wavelength data, will enable one to calibrate the obtained relation for higher redshift galaxies and, possibly, extend the study towards other types of galaxies, such as early-type galaxies off the main sequence.

The complex circumstellar environment of supernova 2023ixf.

The early evolution of a supernova (SN) can reveal information about the environment and the progenitor star. When a star explodes in vacuum, the first photons to escape from its surface appear as a brief, hours-long shock-breakout flare1,2, followed by a cooling phase of emission. However, for stars exploding within a distribution of dense, optically thick circumstellar material (CSM), the first photons escape from the material beyond the stellar edge and the duration of the initial flare can extend to several days, during which the escaping emission indicates photospheric heating3. Early serendipitous observations2,4 that lacked ultraviolet (UV) data were unable to determine whether the early emission is heating or cooling and hence the nature of the early explosion event. Here we report UV spectra of the nearby SN 2023ixf in the galaxy Messier 101 (M101). Using the UV data as well as a comprehensive set of further multiwavelength observations, we temporally resolve the emergence of the explosion shock from a thick medium heated by the SN emission. We derive a reliable bolometric light curve that indicates that the shock breaks out from a dense layer with a radius substantially larger than typical supergiants.

Garlic Origin Traceability and Identification Based on Fusion of Multi-Source Heterogeneous Spectral Information.

The chemical composition and nutritional content of garlic are greatly impacted by its production location, leading to distinct flavor profiles and functional properties among garlic varieties from diverse origins. Consequently, these variations determine the preference and acceptance among diverse consumer groups. In this study, purple-skinned garlic samples were collected from five regions in China: Yunnan, Shandong, Henan, Anhui, and Jiangsu Provinces. Mid-infrared spectroscopy and ultraviolet spectroscopy were utilized to analyze the components of garlic cells. Three preprocessing methods, including Multiple Scattering Correction (MSC), Savitzky-Golay Smoothing (SG Smoothing), and Standard Normalized Variate (SNV), were applied to reduce the background noise of spectroscopy data. Following variable feature extraction by Genetic Algorithm (GA), a variety of machine learning algorithms, including XGboost, Support Vector Classification (SVC), Random Forest (RF), and Artificial Neural Network (ANN), were used according to the fusion of spectral data to obtain the best processing results. The results showed that the best-performing model for ultraviolet spectroscopy data was SNV-GA-ANN, with an accuracy of 99.73%. The best-performing model for mid-infrared spectroscopy data was SNV-GA-RF, with an accuracy of 97.34%. After the fusion of ultraviolet and mid-infrared spectroscopy data, the SNV-GA-SVC, SNV-GA-RF, SNV-GA-ANN, and SNV-GA-XGboost models achieved 100% accuracy in both training and test sets. Although there were some differences in the accuracy of the four models under different preprocessing methods, the fusion of ultraviolet and mid-infrared spectroscopy data yielded the best outcomes, with an accuracy of 100%. Overall, the combination of ultraviolet and mid-infrared spectroscopy data fusion and chemometrics established in this study provides a theoretical foundation for identifying the origin of garlic, as well as that of other agricultural products.