In this paper we analyse the spectro-photometric properties of the Type II supernova which exploded in NGC 3206 at a distance of 19.9 Its early spectra are characterised by narrow high-ionisation emission lines, which are often interpreted as signatures of ongoing interaction between rapidly expanding ejecta and a confined dense circumstellar medium. However, we provide a model for the bolometric light curve of the transient that does not require sources of energy other than radioactive decays and H recombination. Our model can reproduce the bolometric light curve of SN 2024bch if we adopt an ejected mass of M_ bulk ≃5 surrounded by an extended envelope of only 0.2 with an outer radius R_ env cm . Accurate modelling focused on the radioactive part of the light curve, which accounts for incomplete γ-ray trapping, gives a ^ Ni mass of 0.048 We propose that narrow lines are powered by Bowen fluorescence that is induced by scattering of He II Lyα photons. Simple light travel time calculations based on the maximum phase of the narrow emission lines place the inner radius of the H-rich, un-shocked shell at a radius ≃4.4 cm consistent with no interaction occurring between the ejecta and the surrounding circumstellar material during the initial weeks of evolution. Possible signatures of interaction appear only ∼69 after the explosion, although the resulting conversion of kinetic energy into radiation does not seem to contribute significantly to the total luminosity of the transient.

This study investigates the spectrophotometric properties of N-[phenyl(pyridin-2-yl)methylene]hydroxyl¬amine as a novel analytical reagent for the quantitative determination of iron ions in aqueous solutions. In its solid state, the compound is a white crystalline substance, readily soluble in both aqueous and alcoholic media, and does not exhibit absorption in the visible region of the electromagnetic spectrum. Upon interaction with Fe2+ ions, the reagent forms a red-colored complex, which displays a distinct absorption maximum at 528 nm. In contrast, Fe3+ ions form a yellow complex with a maximum at 430 nm. The addition of ascorbic acid as a reducing agent to Fe(III) solutions containing the reagent, or to Fe(III) solutions followed by reagent addition, results in the formation of red-colored complexes identical in both spectral and quantitative characteristics to those of the Fe(II) complex. Given the reagent’s ability to selectively interact with Fe(II), the study explores its use for determining both Fe(II) directly and total iron after reduction. Among various tested reductants (ascorbic acid, hydroxylamine, zinc powder, and stannous chloride), ascorbic acid demonstrated the highest effectiveness and stability over time, making it the optimal choice. Hydroxylamine and zinc required prolonged interaction times, and the use of stannous chloride was hindered by hydrolysis under experimental conditions. The complex exhibits stability over a wide pH range. Maximum absorbance is achieved in the pH range 5.5–7.0, with pH 6.5 chosen as optimal for further studies. The absorption maximum at 528 nm remains constant regardless of pH. The effect of ionic strength was assessed using NaCl, NaNO3, and Na2SO4 at concentrations from 0.005 to 2.0 mol/L. Absorbance fluctuations within this range were below 2%, indicating negligible impact of ionic strength on complex formation. The stoichiometry of the Fe(II)–reagent complex was established using the methods of continuous variations and mole-ratio, showing a 1:2 (metal:ligand) ratio. Based on this, a tentative structure of the complex is proposed. The conditional stability constant of the complex was calculated. Studies revealed that Cu(I), Co(II), Pd(II), Ag(I), Ru(IV), Ir(IV), and Rh(III) form yellow complexes with absorption maxima in the range of 385–425 nm, while Ni(II) and Mn(II) form poorly soluble precipitates. Some lower oxidation states of platinum-group metals such as Ru(II), Ir(II), and Rh(I) form pink to red complexes absorbing at 480–500 nm. However, Cu(II), Zn(II), Cd(II), Pb(II), Al(III), and alkaline/alkaline-earth metals do not react with the reagent and their solutions remain colorless. Given the strong spectral contrast (Δλ > 100 nm) between the Fe(II) complex and potential interferences, the method allows for selective iron determination in complex matrices without separation or masking. The complex obeys Beer’s law in the concentration range of 2.0–30.0 μmol/L, with a molar absorptivity (ε) of 1.80 × 10⁴ L mol⁻¹ cm⁻¹, detection limit of 0.80 μmol/L, and correlation coefficient of 0.9994. The linear regression equation was A = 0.014 + 0.18·C×10⁵. The developed method was successfully applied to the determination of iron in real soil samples collected from different environments in Volyn region, Ukraine. After appropriate sample preparation including acid digestion and organic matter decomposition, the iron content was measured using the described spectrophotometric procedure. The results confirmed the method’s accuracy, sensitivity, and applicability for real sample analysis. Thus, N-[phenyl(pyridin-2-yl)methylene]hydroxylamine presents a highly selective and effective reagent for the spectrophotometric determination of iron in environmental and complex matrices, offering advantages of simplicity, reliability, and low detection limits.

This work is devoted to a detailed study of the complex formation of iron(II) and iron(III) ions with a series of alkyl- and phenyl-substi­tuted salts of 6,7-dihydroxybenzopyrylium (R). Such complexes are of interest due to their potential application as analytical reagents for photometric determination of trace amounts of metals in aqueous systems, particularly in drinking water. The optimal conditions for the reactions in the studied chemical systems have been established: pH range of 3–7 and the analytical signal observed at λ = 550–580 nm. Under these conditions, the maximum color intensity of the complexes is achieved, which indicates their stability and reproducibility. Using the methods of molar ratios and Bent – French analysis, it was shown that under optimal conditions the complex formation proceeds stepwise with the formation of stable compounds with a metal-to-ligand ratio of 1:3. This confirms the ability of iron cations to form polynuclear and multicoordinated structures with R. To characterize the spectrophotometric properties of the complexes, the molar absorption coefficient was determined, and the logarithm of the stability constant (lgβ) was calculated using the Komar method, which allowed a quantitative evaluation of the stability level of the obtained complexes. Special attention was given to the study of the metrological characteristics of the proposed technique: the linearity intervals of the calibration curves, as well as the limits of detection and quantification of iron ions, were established. The practical application of the method was demonstrated on samples of tap water. The obtained results showed that the iron content complies with hygienic standards according to DSANPIN 2.2.4–171.10 and statistically agrees with the results obtained by an independent ICP-OES method, which confirms the reliability and reproducibility of the developed approach. Thus, the conducted research not only expands the understanding of the complex formation of iron with 6,7-dihydroxybenzopyrylium derivatives but also demonstrates the practical applicability of these systems in drinking water quality control and environmental monitoring.

Surface porosity and texture has been found to be an important property for small bodies. Some asteroids and comets can exhibit an extremely high surface porosity in the first millimeter layer. This layer may be produced by various processes and maintained by the lack of an atmosphere. However, the influence of porosity on the spectro-photometric properties of small body surfaces is not yet fully understood. In this study, we looked into the effect of the texture on the spectro-photometric properties of Phobos regolith spectroscopic simulants. Macro- and micro-porosity were created by mixing the simulants with ultra-pure water, producing ice-dust particles, and then sublimating the water. The sublimation of the water ice enabled the production of porous and rough powdered simulants with significant micro- and macro-porosity associated with macro-roughness. The reflectance spectroscopic properties in the visible and near-infrared (0.5–4.2 μ m ) demonstrate a brightening of the porous samples in comparison to the compact ones. One simulant exhibits a bluing of the spectral slope after increasing porosity, which is likely linked to the presence of expandable phyllosilicates. In the mid-infrared range, a contrast increase of the 10 μ m emissivity-related plateau due to silicates is observed. This spectral feature is typically observed as a 10 μ m emissivity plateau on some asteroids, making the mid-infrared region important for assessing mineralogy and surface texture. Photometry reveals a modification of the phase reddening behavior between the compact powder and the sublimation residue for both simulants. However, the observed behavior is different between the simulants, suggesting that the phase reddening may be dependent on the composition of the simulants. The phase curves of the sublimation residues exhibit a higher contribution of forward scattering. The derivation of the Hapke parameters indicates an increase in roughness for the porous sample, but no significant modification of the opposition effect. The modifications of the spectrophotometric properties observed in this experiment are definitely due to the textural changes obtained after sublimation, which depend on the initial composition of the simulants. This study aims to provide new insights into the understanding of porosity by using two Phobos simulants in the context of the upcoming JAXA/Martian Moons eXploration mission. We suggest that the Phobos blue unit may be due to the presence of a highly porous layer, rather than only to space-weathering processes, as often postulated. • We observed the emergence of a 10 μ m -plateau for porous samples. • The increase of porosity and roughness modify phase function parameters. • The increase of porosity and roughness modify the phase reddening. • The increase of porosity induces spectral slope bluing. • The bluing may explain the difference between the blue and red units on Phobos.

Context. 2024 PT5 is a tiny (D ≤ 10 m) near-Earth asteroid (NEA) discovered in August 2024. 2024 PT5 was gravitationally bound to the Earth-Moon system from September to November 2024 and classified as a mini-moon. Several quick response observations suggest that 2024 PT5 has a lunar ejecta origin, while the rotation state and albedo, essential properties for investigating its origin, are not well constrained. Aims. We aim to characterize the spectrophotometric properties of 2024 PT5 by ground-based observations to test its taxonomic classification and origin. Methods. We performed visible to near-infrared multicolor photometry of 2024 PT5 from data taken using the TriColor CMOS Camera and Spectrograph (TriCCS) on the Seimei 3.8 m telescope during January 4–10, 2025. The Seimei/TriCCS observations of 2024 PT5 cover phase angles from 14 deg to 27 deg, and were obtained in the ɡ, r, i, and ɀ bands in the Pan-STARRS system. In addition, we analyzed Y, J, H, and K photometry taken with the Multi-Object Spectrograph for Infrared Exploration (MOSFIRE) on the Keck I 10-m telescope on January 16–17, 2025. Results. Our light curves show brightness variations over time periods of several tens of minutes. We infer that 2024 PT5 is in a tumbling state and has a light curve amplitude of about 0.3 mag. Visible and near-infrared color indices of 2024 PT5, ɡ – r = 0.567 ± 0.044, r – i = 0.155 ± 0.009, r – ɀ = 0.147 ± 0.066, Y – J = 0.557 ± 0.046, J – H = 0.672 ± 0.078, and H – Ks = 0.148 ± 0.098, indicate that 2024 PT5 is an S-complex asteroid, largely consistent with previous observations. Using the H–G model, we derived an absolute magnitude, HV,HG, of 27.72 ± 0.09 and a slope parameter, GV, of 0.223 ± 0.073 in the V band. A geometric albedo of 2024 PT5 was derived to be 0.26 ± 0.07 from the slope of its photometric phase curve. This albedo value is typical of the S- and Q-type NEAs. Conclusions. Using the albedo and absolute magnitude, the equivalent diameter of 2024 PT5 is estimated to be 7.4 ± 1.0 m. The color properties of 2024 PT5 derived from our observations match the ones of rock samples taken from the lunar surface, which agrees with previous studies.

Abstract This study focuses on optimizing carrageenan-cornstarch edible coatings to address the challenges of water resistance and improve the functional properties of biopolymer-based food packaging. Unlike previous studies, this research emphasizes the use of Response Surface Methodology (RSM) to systematically optimize the formulation, providing a novel approach to achieving multi-response optimization with minimal experimental effort. Thirteen formulations were prepared with varying concentrations of carrageenan (1-2 grams), cornstarch (0-2 grams), and glycerol (1% v/v) to minimize key parameters, including thickness, moisture content, swelling, solubility, spectrophotometric properties, and Water Vapor Transmission Rate (WVTR). The R² values for these properties were: 81.18% (thickness), 98.51% (moisture content), 63.88% (swelling), 96.69% (solubility), 74.04% (spectrophotometric properties), and 64.09% (WVTR). The optimal formulation (1.04 grams of carrageenan and 1.69 grams of cornstarch) produced an edible coating with desirable properties: 0.08 mm thickness, 32.18% moisture content, 11.48% swelling, 1.81% solubility, 4.90% spectrophotometric, and 0.04 g/(m2.24h) WVTR. This formulation achieved a desirability score of 0.6321, demonstrating its potential as a sustainable alternative for food packaging with enhanced performance.

The presented article provides information on spectral reflectance.The reflection of light by soil depends on a number of chemical elements and physical properties of soils.However, a multiparameter analysis of the simultaneous influence of these factors on the spectral coefficients of soils has not yet been carried out.In general, the spectral curves of all soil types are subject to changes in certain parts of electromagnetic waves depending on the parent rocks, the amount of humus and the ratio of its forms, mechanical composition, minerals, carbonates, iron oxides, etc.This confirms the importance of studying spectrophotometric studies in soils.The article presents the results of studies of the spectrophotometric properties of Salyan plain soils depending on humus, carbonates, humidity, density, salts, etc.These indicators significantly affect the integral reflectance of soils.Thus, the greater the amount of humus in soils, the lower the spectral reflectance, and the greater the amount of carbonates and salts, the higher the spectral reflectance.The dependence of the intensity of soil reflectance coefficients and the spectral composition on moisture content and changes in the size of their fractions indicate that it is necessary to study the color and spectral reflectance of soils within certain conditions.In most of the works carried out in this direction, it is recommended to conduct the color and spectral reflectance of soils on air-dried soil samples with sizes between 1.0-0.01mm.Studying the regularity of the dependence of spectrophotometric properties on various factors allows us to eliminate some shortcomings.To increase the effectiveness of the work being done, it is necessary to quantitatively assess the response of reflection coefficients to influencing factors.Determining the regularity of the optical properties of soils leads to the study of new information about the soil, which can be used as an additional factor in soil research.

The presented article provides information on spectral reflectance.The reflection of light by soil depends on a number of chemical elements and physical properties of soils.However, a multiparameter analysis of the simultaneous influence of these factors on the spectral coefficients of soils has not yet been carried out.In general, the spectral curves of all soil types are subject to changes in certain parts of electromagnetic waves depending on the parent rocks, the amount of humus and the ratio of its forms, mechanical composition, minerals, carbonates, iron oxides, etc.This confirms the importance of studying spectrophotometric studies in soils.The article presents the results of studies of the spectrophotometric properties of Salyan plain soils depending on humus, carbonates, humidity, density, salts, etc.These indicators significantly affect the integral reflectance of soils.Thus, the greater the amount of humus in soils, the lower the spectral reflectance, and the greater the amount of carbonates and salts, the higher the spectral reflectance.The dependence of the intensity of soil reflectance coefficients and the spectral composition on moisture content and changes in the size of their fractions indicate that it is necessary to study the color and spectral reflectance of soils within certain conditions.In most of the works carried out in this direction, it is recommended to conduct the color and spectral reflectance of soils on air-dried soil samples with sizes between 1.0-0.01mm.Studying the regularity of the dependence of spectrophotometric properties on various factors allows us to eliminate some shortcomings.To increase the effectiveness of the work being done, it is necessary to quantitatively assess the response of reflection coefficients to influencing factors.Determining the regularity of the optical properties of soils leads to the study of new information about the soil, which can be used as an additional factor in soil research.

Abstract A novel radiochromic polymeric film dosimeter based on povidone-iodine was prepared. The spectrophotometric properties of unirradiated and gamma-irradiated films were investigated using a UV–Vis spectrophotometer. This study proved that the polymeric films of PVP-I/PVA can be used as gamma radiation dosimeters in the dose range from 1 to 25 kGy as their color appears and intensity increases with increasing gamma radiation absorbed dose peaking at λ max = 295 nm and 365 nm. The stability of the color of the polymeric films, effects of temperature and relative humidity were measured. These film dosimeters can be applied in many fields as they have many advantages.

Investigation of mono-nuclear cobalt(II) complexes with a tri-dentate quinoxalyl-hydrazone ligand for their potential in biological research and interaction with ct-DNA.

Context. Despite the increasing prevalence of radio-loud (RL) sources at cosmic noon, our understanding of the underlying physics that governs the accretion disc outflows in these particular sources and its dissimilarity with radio-quiet (RQ) quasars remains somewhat limited. Aims. Disentangling the real impact of the radio-loudness and accretion on the outflow parameters remains a challenge to this day. We present ten new spectra of high-redshift and high-luminosity quasars and combine these with previous data at both high and low redshift with the aim being to evaluate the role of the feedback from RL and RQ AGN. The final high-redshift (1.5 ≲ z ≲ 3.9), high-luminosity (47.1 ≤ log(L) ≤ 48.5) sample consists of a combination of 60 quasars from our ISAAC and the Hamburg-ESO surveys. The low-redshift (z ≤ 0.8) sample has 84 quasars that have been analyzed in the optical and with the Faint Object Spectrograph (FOS) data in the UV. Methods. We perform a multicomponent analysis of optical and UV emission line profiles along the quasar main sequence, and provide a relation that can be used to estimate the main outflow parameters (mass rate, thrust, and kinetic power) in both the BLR and NLR through the analysis of the [O III]λ5007 and C IVλ1549 emission lines. Results. Spectrophotometric properties and line profile measurements are presented for Hβ+[O III]λλ4959,5007, Si IVλ1397+O IV]λ1402, C IVλ1549+He IIλ1640, and the 1900 Å blend. High-ionization lines, such as C IVλ1549 and [O III]λ5007, usually present a significant asymmetry toward the blue, especially in radio-quiet sources. This is strong evidence of outflow motions. In the ISAAC sample, 72% of the quasars where [O III] is clearly detected present significant outflows, with centroid velocity at half intensity blueshifted to values of greater than ∼250 km s−1. Radio-loud quasars tend to present slightly more modest blueshifted components in both the UV and optical ranges. The behavior of [O III]λ5007 mirrors that of C IVλ1549, with blueshift amplitudes between the two lines showing a high degree of correlation, which appears unaffected by the presence of radio emission. Conclusions. In contrast to the situation at low redshift, both RL and RQ AGN outflow parameters at high luminosity appear in the range needed to provide feedback effects on their host galaxies. Both high- and low-z RL quasars exhibit smaller outflows compared to RQ quasars, suggesting a potential role of radio-loudness in mitigating outflow effects. Nevertheless, the radio-loudness effect on AGN feedback is much less significant than the effect of accretion, with this latter emerging as the main driver of nuclear outflows.

Citric acid crosslinked Carica papaya seeds mucilage-based hydrogel film were synthesized and characterized. The extracted mucilage and hydrogel film were explored by determining their physicochemical, thermal, micrometric and spectrophotometric properties. The results of attenuated total reflectance-Fourier transform infrared spectroscopy and solid state 13C-nuclear magnetic resonance spectroscopy confirms the emergence of ester crosslinking between the mucilage and citric acid. The swelling study of mucilage and hydrogel film revealed good swelling ability of prepared hydrogel film. Also, the hydrogel film showed better thermal stability than the mucilage. The current study showed that papaya seed mucilage can be used as a bio-based source for hydrogel using citric acid as a cross-linker. Further, it can be potentially explored in pharmaceutical, food and cosmetic industries.

ABSTRACT Objective: In the framework of the Cometary Physics Laboratory (CoPhyLab) and its sublimation experiments of cometary surface analogues under simulated space conditions, we characterize the properties of intimate mixtures of juniper charcoal and SiO2 chosen as a dust analogue (Lethuillier et al. 2022). We present the details of these investigations for the spectrophotometric properties of the samples. Methods: We measured these properties using a hyperspectral imager and a radio-goniometer. From the samples’ spectra, we evaluated reflectance ratios and spectral slopes. From the measured phase curves, we inverted a photometric model for all samples. Complementary characterizations were obtained using a pycnometer, a scanning electron microscope and an organic elemental analyser. Results: We report the first values for the apparent porosity, elemental composition, and VIS-NIR spectrophotometric properties for juniper charcoal, as well as for intimate mixtures of this charcoal with the SiO2. We find that the juniper charcoal drives the spectrophotometric properties of the intimate mixtures and that its strong absorbance is consistent with its elemental composition. We find that SiO2 particles form large and compact agglomerates in every mixture imaged with the electron microscope, and its spectrophotometric properties are affected by such features and their particle-size distribution. We compare our results to the current literature on comets and other small Solar system bodies and find that most of the characterized properties of the dust analogue are comparable to some extent with the spacecraft-visited cometary nuclei, as well as to Centaurs, Trojans, and the bluest TNOs.

The spectrophotometric properties of two study areas in the Ingenii swirl region show that the combined effects of multiple processes are required to explain the regolith’s mineralogical and physical properties. Production of the swirl regions requires mobilization of the regolith in addition to preferential radiation shielding of subareas. The discovery of topographic correlations between on- and off-swirl (dark lanes) clearly shows that the on-swirl regions are statistically lower than the off-swirl dark lanes by 2–3 m. Photometric analyses show no microscale roughness differences between on- and off-swirl, suggesting no differences in the regolith’s fairy-castle structure between the two swirl regions. The photometric properties of one of the study areas suggest that off-swirl dark lanes may have a more complicated grain structure than on-swirl areas. Enhanced abundances of plagioclase are observed on-swirl in both study areas. Enhanced abundances of FeO and orthopyroxene are observed off-swirl in both areas. No variations in olivine or clinopyroxene abundance were observed for either study area. The discovery of topographic correlations coupled with the similarities in structural properties provides new constraints on the types of processes acting on lunar swirl surfaces.

Despite significant progress in the development of phototherapy drugs, it is widely recognized that natural products remain the primary source of new photoactive compounds. Exploring uncharted flora in the east-central region of Argentina may offer a vast array of opportunities to isolate new photoactive molecules or plant extracts with high potential for use in antimicrobial photodynamic therapy (aPDT) against Candida albicans. To assess the photofungicidal potential of T. sinuata ("contrayerba") against C. albicans, the extracts underwent spectroscopic and chromatographic analysis, resulting in the identification of furanocoumarin metabolites with similar spectrophotometric properties in all extracts. The extract profiles were created using UHPLC-DAD, and seven furanocoumarins (FCs) were detected. The highest photoinactivation against C. albicans was observed for dicholormethanic extracts (MFC = 62.5 μg/mL), equal to xanthotoxin employed as a positive control. Furthermore, we determine that photochemical mechanisms dependent on oxygen (type I and type II processes) and mechanisms independent of oxygen (photoadduct formation) are involved in the death of these yeasts. These results support the use of native plants of the east-central region of Argentina as potent sensitizers for aPDT and suggest that they can replace xanthotoxin in treating superficial yeast infections of the skin.

This study shows the prospects of using "Bazacryl" brand dyes in spectrophotometric analysis. On the basis of previous studies, their main spectrophotometric and protolytic characteristics have already been established, which made it possible to find out the optimal conditions for the formation of ionic associates of anionic surfactants with "Bazakrils". The studied dyes are characterized by a sufficiently high color intensity within a wide range of changes in the acidity of the medium, and in terms of these properties, they are not inferior to the majority of known basic dyes used in analytical practice. The kinetic factors of extraction were studied. As a result, the extraction equilibrium is established after 10-30 seconds of mixing the phases and practically does not depend on the used extractant, but 1-3 min. centrifugation is sufficient for complete phase separation. The optical density of the extracts of the formed IA does not change within 2 hours. It was established that such dyes show the ability to form IA from APAR and can serve as analytical reagents for their determination. The optimal conditions for the formation and extraction of IA APAR with new dyes have been established. A new, simple and rapid method for determining APAR in various samples of wastewater and natural waters, detergents, etc. is proposed.
 Keywords: dyes; spectrophotometry; ionic associate; protolytic properties; spectrophotometric properties.

Context. Supermassive stars (SMSs) with masses M ≳ 103 − 104 M⊙ formed by runaway collisions in young, massive, and dense star clusters have been invoked as a possible solution to the problem of the presence of multiple stellar populations and peculiar abundance patterns observed in globular clusters (GCs). However, no such objects have been observed so far. Aims. We aim to develop observational strategies to search for SMSs hosted within young massive clusters (thought to be the precursors of GCs) using both photometric and spectroscopic observations. Such strategies could be applicable in a relatively general fashion. Methods. We used theoretical predictions of the spectra of SMSs and SMS-hosting clusters, together with predictions from standard simple stellar populations to examine their impact on color–color diagrams and on individual optical spectral lines (primarily hydrogen emission and absorption lines). As a first step, we applied our search strategies to a sample of about 3000 young star clusters (YSCs) from two nearby galaxies with multiband observations from the HST and optical integral-field spectroscopy obtained with MUSE on the Very Large Telescope. Results. We focus on models for SMSs with large radii (corresponding to Teff ≲ 7000 K), which predict strong Balmer breaks, and construct proper color–color diagrams to select the corresponding SMS-hosting cluster candidates. We show that the spectrophotometric properties of these latter are similar to those of normal clusters with ages of a few hundred million years. However, the cluster SEDs show signs of composite stellar populations due to the presence of nebular lines (Hα and others). Examining the photometry, overall SEDs, and the spectra of approximately 100 clusters with strong Balmer breaks, we find several objects with peculiar SEDs, the presence of emission lines, or other peculiar signatures. After careful inspection of the available data, we do not find good candidates of SMS-hosting clusters. In most cases, the composite spectra can be explained by multiple clusters or H II regions inside the aperture covered by the spectra, by contamination from a planetary nebula or diffuse gas, or by improper background subtraction. Furthermore, most of our candidate clusters are too faint to host SMSs. Conclusions. We demonstrate a strategy to search for SMSs by applying it to a sample of YSCs in two nearby galaxies. Our method can be applied to larger samples and also extended to higher redshifts with existing and upcoming telescopes, and therefore should provide an important test for GC-formation scenarios invoking such extreme stars.

ABSTRACTMid-infrared (mid-IR) variability in young stellar objects (YSOs) is driven by several physical mechanisms, which produce a variety of amplitudes and light-curve shapes. One of these mechanisms, variable disc accretion, is predicted by models of episodic accretion to drive secular variability, including in the mid-IR. Because the largest accretion bursts are rare, adding new objects to the YSO eruptive variable class aids our understanding of the episodic accretion phenomenon and its possible impact on stellar and planetary formation. A previous analysis of 6.5 yr of NeoWISE light curves (3–5 μm) of ∼7000 nearby YSOs found an increase in the fraction of variability and variability amplitude for objects at younger stages of evolution. To help interpret these light curves, we have obtained low- and high-resolution near-IR spectra of 78 objects from this sample of YSOs. In this work, we present the analysis of nine nearby YSOs (d<1 kpc) that show the characteristics of known classes of eruptive variable YSOs. We find one FU Orionis (FUor)-like source, one EX Lupi type object, and six YSOs with mixed characteristics or V1647 Ori like objects. The varied characteristics observed in our sample are consistent with recent discoveries of eruptive YSOs. We discuss how a wide range in YSO outburst parameters (central mass, maximum accretion rate during outburst, evolutionary stage, and/or instability leading to the outburst) may play a significant role in the observed spectrophotometric properties of YSO outbursts.

Sustainable recovery of melanoidins from thermal hydrolyzed sludge by macroporous resin and properties characterization

Context. The 4D Eigenvector 1 empirical formalism (4DE1) and its main sequence (MS) for quasars has emerged as a powerful tool for organising the diversity among quasar populations, as several key observational measures and physical parameters are systematically changing along it. Aims. Trends revealed by 4DE1 are very well established to explain all the diverse characteristics seen in low-redshift quasar samples. Nevertheless, the situation is far less clear when dealing with high-luminosity and high-redshift sources. Here, we aim to evaluate the behaviour of our sample of 22 quasars at high redshift (2.2 ≤ z ≤ 3.7) and high luminosity (47.39 ≤ Lbol ≤ 48.36) in the context of the 4DE1. Methods. Our approach involves studying quasar physics through a spectroscopic exploration of UV and optical emission line diagnostics. We used new observations from the ISAAC instrument at ESO-VLT and primarily from the SDSS to cover the optical and the UV rest-frames, respectively. The emission lines were characterised both via a quantitative parametrisation of the line profiles and a decomposition of the emission line profiles using multicomponent fitting routines. Results. We provide spectrophotometric properties and line profile measurements for Hβ+[O III]λλ4959,5007, as well as Si IVλ1397+O IV]λ1402, C IVλ1549+He IIλ1640, and the 1900 Å blend (including Al IIIλ1860, Si III]λ1892, and C III]λ1909). For six out of the 22 objects, a significantly blueshifted component on the Hβ profile is present. In 14 out of 22 cases, an Hβ outflowing component associated with [O III] is detected. The majority of [O III]λλ4959,5007 emission line profiles show blueshifted velocities higher than 250 km s−1. We find extremely broad [O III]λλ4959,5007 emission that is comparable to the width of Hβ broad profile in some highly accreting quasars. The [O III]λλ4959,5007 and C IVλ1549 blueshifts show very high amplitudes and a high degree of correlation. The line widths and shifts are correlated for both [O III]λλ4959,5007 and C IVλ1549, suggesting that emission from outflowing gas is providing a substantial broadening effect to both lines. Otherwise, the links between C IVλ1549 centroid velocity at half intensity (c(1/2)), Eddington ratio (L/LEdd), and bolometric luminosity are found to be in agreement with previous studies of high-luminosity quasars. Conclusions. Our analysis suggests that the behaviour of quasars of very high luminosity all along the main sequence is strongly affected by powerful outflows involving a broad range of spatial scales. The main sequence correlations remain valid at high redshift and high luminosity even if a systematic increase in line width is observed. Scaling laws based on UV Al IIIλ1860 and Hβ emission lines are equally reliable estimators of MBH.