bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exploring the nature of an ultraluminous X-ray source in NGC 628
Authors: Avdan H. , Avdan S. 
Published: August 2024

Aims. In this work, we study the X-ray spectral and temporal properties of an ultraluminous X-ray source (ULX) in NGC 628 by using multi-epoch archival X-ray data. The physical parameters were estimated in each epoch in order to constrain the nature of the compact object in the system. Also, the optical counterpart candidates of the ULX were examined using the archival Hubble Space Telescope (HST)/Wide Field Camera 3 (WFC3) data.
Methods.XMM-Newton, Chandra, and Swift data were used to create the long-term light curve (which covers a period of 22 years) and perform the spectral analysis. Lomb-Scargle periodograms of the source were constructed to examine the short-term variability in each epoch. In order to search for an optical counterpart in the HST/WFC3 images, a relative astrometric correction was initially applied to the Chandra and HST/WFC3 images.
Results. The X-ray flux of the source changes by a factor of ∼200 throughout the observations. The previously detected quasi-periodic signal (in the range of 0.1−0.4 mHz) was confirmed by using the Lomb-Scargle method. After astrometric correction, two optical counterpart candidates were detected for the source. The obtained spectral energy distributions in the optical band for both candidates indicate that the optical emission is dominated by the irradiation of the accretion disc. Considering the best-fit model parameters of the multi-colour disc black-body model, we derived the mass of the black hole in the system as being in the range of (5−28) M⊙. Nonetheless, the long-term variability and the spectral transitions in the hardness–luminosity diagram make it difficult to rule out the neutron star scenario.
A grid of self-consistent MSG (MARCS-StaticWeather-GGchem) cool stellar, sub-stellar, and exoplanetary model atmospheres
Authors: Jørgensen Uffe G. , Amadio Flavia , Campos Estrada Beatriz , Møller Kristian Holten , Schneider Aaron D. , Balduin Thorsten , D’Alessandro Azzurra , Symeonidou Eftychia , Helling Christiane , Nordlund Åke , Woitke Peter 
Published: August 2024

Context. In this paper we present a grid of self-consistent 1D model atmospheres of cool stars, sub-stellar objects, and exoplanets in the effective temperature range 300-3000 K, including cloud formation, chemical non-equilibrium effects, and stellar irradiation.
Aims. The new grid extends the classical MARCS model atmosphere grid from 2008 towards lower effective temperatures and a broader range of object types.
Methods. The new model atmosphere computations, MSG, are based on a combination of three well-tested codes, the classical MARCS 1D atmospheres, the StaticWeather cloud formation code, and the GGchem chemical equilibrium code. The combined code has been updated with new and more complete molecular and atomic opacities, cloud formation, and advanced chemical equilibrium calculations, and we also added new numerical methods at low temperatures to allow for a more robust convergence.
Results. The coupling between the MARCS radiative transfer and GGchem chemical equilibrium computations has effectively made it possible to reach convergence based on the electron pressure for warmer models and gas pressure for cooler models, enabling self-consistent modelling of stellar, sub-stellar, and exoplanetary objects in a very wide range of effective temperatures. We will make new cloud-free and non-irradiated models for solar metallicity and a selected variety of other chemical compositions immediately available from our home page (https://cels.nbi.ku.dk). Illustrative examples of cloudy and irradiated models as well as models based on non-equilibrium chemistry are also presented, and we will describe these in more detail and make them available upon completion at the same place for a larger range of parameter space.
Conclusions. For solar metallicity models, the new additional molecular opacities only affect the structure of models cooler than Teff = 2500 K, and the effect becomes substantial for models below Teff ~1500 K. Atomic line opacities are important for models warmer than ~3000 K. The line profile of the molecular opacities may have a larger effect on the model structure than previously anticipated, particularly in the uppermost layers at low gas pressure. The qualitative changes in the relative abundances of TiO, H2O, CH4, NH3, and other molecules in our models follow the observationally defined M, L, T (and Y) sequences, but they also reveal more complex and depth-dependent abundance changes and therefore a spectral classification depending on more parameters. The self-consistent coupling to StaticWeather cloud computations allows for detailed comparison between nucleation and observed relative dimming of different spectral bands, with advanced applications for new identification methods of potential exoplanetary biology.
SpectroTranslator: Deep-neural network algorithm for homogenising spectroscopic parameters
Authors: Thomas G. F. , Battaglia G. , Gran F. , Fernández-Alvar E. , Tsantaki M. , Pancino E. , Hill V. , Kordopatis G. , Gallart C. , Turchi A. , Masseron T. 
Published: August 2024

Context. In modern Galactic astronomy, stellar spectroscopy plays a pivotal role in complementing large photometric and astrometric surveys and enabling deeper insights to be gained into the chemical evolution and chemo-dynamical mechanisms at play in the Milky Way and its satellites. Nonetheless, the use of different instruments and dedicated pipelines in various spectroscopic surveys can lead to differences in the derived spectroscopic parameters.
Aims. Efforts to homogenise these surveys onto a common scale are essential to maximising their scientific legacy. To this aim, we developed the SPECTROTRANSLATOR, a data-driven deep neural network algorithm that converts spectroscopic parameters from the base of one survey (base A) to that of another (base B).
Methods. SPECTROTRANSLATOR is comprised of two neural networks: an intrinsic network, where all the parameters play a role in computing the transformation, and an extrinsic network, where the outcome for one of the parameters depends on all the others, but not the reverse. The algorithm also includes a method to estimate the importance that the various parameters play in the conversion from base A to B.
Results. To demonstrate the workings of the algorithm, we applied it to transform effective temperature, surface gravity, metallicity, [Mg/Fe], and line-of-sight velocity from the base of GALAH DR3 into the APOGEE-2 DR 17 base. We demonstrate the efficiency of the SPECTROTRANSLATOR algorithm to translate the spectroscopic parameters from one base to another, directly using parameters by the survey teams. We were able to achieve a similar performance than previous works that have performed a similar type of conversion but using the full spectrum, rather than the spectroscopic parameters. This allowed us to reduce the computational time and use the output of pipelines optimised for each survey. By combining the transformed GALAH catalogue with the APOGEE-2 catalogue, we studied the distribution of [Fe/H] and [Mg/Fe] across the Galaxy and we found that the median distribution of both quantities present a vertical asymmetry at large radii. We attribute it to the recent perturbations generated by the passage of a dwarf galaxy across the disc or by the infall of the Large Magellanic Cloud.
Conclusions. Several aspects still need to be refined, such as the question of the optimal way to deal with regions of the parameter space meagrely populated by stars in the training sample. However, SPECTROTRANSLATOR has already demonstrated its capability and is poised to play a crucial role in standardising various spectroscopic surveys onto a unified framework.
JWST reveals the rapid and strong day-side variability of 55 Cancri e
Authors: Patel J. A. , Brandeker A. , Kitzmann D. , Petit dit de la Roche D. J. M. , Bello-Arufe A. , Heng K. , Meier Valdés E. , Persson C. M. , Zhang M. , Demory B.-O. , Bourrier V. , Deline A. , Ehrenreich D. , Fridlund M. , Hu R. , Lendl M. , Oza A. V. , Alibert Y. , Hooton M. J. 
Published: August 2024

Context. The nature of the close-in rocky planet 55 Cnce is puzzling, despite it having been observed extensively. Its optical and infrared occultation depths show temporal variability, in addition to a phase curve variability observed in the optical.
Aims. We wish to explore the possibility that the variability originates from the planet being in a 3:2 spin–orbit resonance, and thus showing different sides during occultations. We proposed and were awarded Cycle 1 time at the James Webb Space Telescope (JWST) to test this hypothesis.
Methods. JWST/NIRCam (Near Infrared Camera) observed five occultations (secondary eclipses) of the planet – of which four were observed within a week – simultaneously at 2.1 and 4.5 µm. While the former gives band-integrated photometry, the latter provides a spectrum between 3.9–5.0 µm.
Results. We find that the occultation depths in both bandpasses are highly variable and change between a non-detection (−5 ± 6 ppm and 7 ± 9 ppm) to 96 ± 8 ppm and 119−19+34 ppm at 2.1 µm and 4.5 µm, respectively. Interestingly, the variations in both bandpasses are not correlated and do not support the 3:2 spin-orbit resonance explanation. The measured brightness temperature at 4.5 µm varies between 873–2256 K and is lower than the expected day-side temperature of bare rock with no heat redistribution (2500 K), which is indicative of an atmosphere. Our atmospheric retrieval analysis of occultation depth spectra at 4.5 µm finds that different visits statistically favour various atmospheric scenarios including a thin outgassed CO/CO2 atmosphere and a silicate rock vapour atmosphere. Some visits even support a flat line model.
Conclusions. The observed variability could be explained by stochastic outgassing of CO/CO2, which is also hinted at by retrievals. Alternatively, the variability observed at both 2.1 and 4.5 µm could be the result of a circumstellar patchy dust torus generated by volcanism on the planet.
Insight into the occurrence of particle acceleration through the investigation of Wolf–Rayet stars using uGMRT observations
Authors: Blanco A. B. , De Becker M. , Saha A. , Tej A. , Benaglia P. 
Published: August 2024

Context. Massive stars produce strong stellar winds that consist of continuous outflows of material at speeds of thousands of km s−1. These winds convey large amounts of kinetic power, especially in the case of Wolf–Rayet (WR) stars. When these winds interact with nearby material, they will likely produce shocks. Among other processes, particle acceleration is expected to occur. This is particularly well established in the case of massive binary systems, where the stellar winds collide, allowing these systems to be identified thanks to the detection of synchrotron radio emission, produced by a population of relativistic particles accelerated in the shocks.
Aims. Our goal is to investigate the occurrence of particle acceleration among massive stars in their pre-supernova evolution phases.
Methods. We observed a subset of five WR stars in the radio domain using the upgraded Giant Metrewave Radio Telescope (uGMRT), located in India. The observations were carried out in bands 4 (550–950 MHz) and 5 (1050–1450 MHz) for all the targets.
Results. We detected radio emission for only WR 110 in bands 4 and 5. Its thermal spectrum displays a consistent index of +0.74 down to uGMRT bands. The four other targets were not detected and we derived 3σ upper limits on their flux density. Our upper limits in Band 4 are the first provided for these targets below 1 GHz. None of the targets was identified as a synchrotron radio emitter in these radio bands.
Conclusions. If some synchrotron emission is produced in these systems, the non-detection with the uGMRT can be most likely attributed to strong free-free absorption (FFA). This is especially relevant for WR98a which is catalogued as a particle accelerator based on previous measurements at higher radio frequencies. The prominence of FFA constitutes a severe obstacle to identifying particle accelerators in the radio domain.
Flare heating of the chromosphere: Observations of flare continuum from GREGOR and IRIS
Authors: García-Rivas M. , Kašparová J. , Berlicki A. , Švanda M. , Dudík J. , Čtvrtečka D. , Zapiór M. , Liu W. , Sobotka M. , Pavelková M. , Motorina G. G. 
Published: August 2024

Context. On 2022 May 4, an M5.7 flare erupted in the active region NOAA 13004, which was the target of a coordinated campaign between GREGOR, IRIS, Hinode, and ground-based instruments at the Ondřejov observatory. A flare kernel located at the edge of a pore was co-observed by the IRIS slit and GREGOR HiFI+ imagers.
Aims. We investigated the flare continuum enhancement at different wavelength ranges in order to derive the temperature of the chromospheric layer heated during the flare.
Methods. All datasets were aligned to IRIS slit-jaw images. We selected a pixel along the IRIS slit where the flare kernel was captured and evaluated multi-wavelength light curves within it. We defined a narrow IRIS near-UV band that comprises only continuum emission. The method, which assumes that the flare continuum enhancement is due to optically thin emission from hydrogen recombination processes, was applied to obtain a lower limit on the temperature in the layer where the continuum enhancement was formed.
Results. We determined a lower limit for the temperature and its time evolution in the chromospheric layer heated during the flare in the range of (3–15) ×103 K. The mean electron density in that layer was estimated to be ∼1 × 1013 cm−3.
Conlcusions. Multi-wavelength flare co-observations are a rich source of diagnostics. Due to the rapidly evolving nature of flares, the sit-and-stare mode is key to achieving a high temporal cadence that allows one to thoroughly analyse the same flare structure.
Testing the flux tube expansion factor - solar wind speed relation with Solar Orbiter data
Authors: Dakeyo J.-B. , Rouillard A. P. , Réville V. , Démoulin P. , Maksimovic M. , Chapiron A. , Pinto R. F. , Louarn P. 
Published: August 2024

Context. The properties of the solar wind measured in situ in the heliosphere are largely controlled by energy deposition in the solar corona, which is in turn closely related to the properties of the coronal magnetic field. Previous studies have shown that long-duration and large-scale magnetic structures show an inverse relation between the solar wind velocity measured in situ near 1 au and the expansion factor of the magnetic flux tubes in the solar atmosphere.
Aims. The advent of the Solar Orbiter mission offers a new opportunity to analyse the relation between solar wind properties measured in situ in the inner heliosphere and the coronal magnetic field. We exploit this new data in conjunction with models of the coronal magnetic field and the solar wind to evaluate the flux expansion factor and speed relation.
Methods. We use a Parker-like solar wind model, the “isopoly” model presented in previous works, to describe the motion of the solar wind plasma in the radial direction and model the tangential plasma motion due to solar rotation with the Weber and Davis equations. Both radial and tangential velocities are used to compute the plasma trajectory and streamline from Solar Orbiter location sunward to the solar ‘source surface’ at rss. We then employed a potential field source surface (PFSS) model to reconstruct the coronal magnetic field below rss to connect wind parcels mapped back to the photosphere.
Results. We found a statistically weak anti-correlation between the in situ bulk velocity and the coronal expansion factor, for about 1.5 years of solar data. Classification of the data by source latitude reveals different levels of anticorrelation, which is typically higher when Solar Orbiter magnetically connects to high latitude structures than when it connects to low latitude structures. We show the existence of a fast solar wind that originates in strong magnetic field regions at low latitudes and undergoes large expansion factor. We provide evidence that such winds become supersonic during the super-radial expansion (below rss) and are theoretically governed by a positive v–f correlation. We find that faster winds exhibit, on average, a flux tube expansion at a larger radius than slower winds.
Conclusions. An anticorrelation between solar wind speed and expansion factor is present for solar winds originating in high latitude structures in solar minimum activity, typically associated with coronal hole-like structures, but this cannot be generalized to lower latitude sources. We have found extended time intervals of fast solar wind associated with both large expansion factors and strong photospheric magnetic fields. Therefore, the value of the expansion factor alone cannot be used to predict the solar wind speed. Other parameters, such as the height at which the expansion gradient is the strongest, must also be taken into account.
Detection of faint secondary companions in spectroscopic binaries
Authors: González J. F. , Martínez C. I. , Alejo A. 
Published: August 2024

Context. Most known spectroscopic binaries are detected through the variation in the radial velocity of the primary star, while the spectral features of the secondary companion remain hidden in the noise.
Aims. We present a novel technique for the spectroscopic detection of low-luminosity secondary companions of binary stars. The main goal is to estimate the mass ratio even when the radial velocity of the secondary cannot be measured in individual spectra.
Methods. The method aims to bring together all the spectral information of the secondary component into one single feature. In a first step, a spectral disentangling technique is used in an automatic way for a grid of possible values of the mass ratio. Then, the resulting series of secondary component spectra are compared with a grid of synthetic templates with a technique inspired by spectral cross-correlations. By optimizing a function indicative of the significance of the secondary detection, the mass ratio and an estimate of effective temperature are derived.
Results. We apply our method to different types of objects and observational datasets: three single-lined spectroscopic binaries in the open cluster Blanco 1 observed at mid-spectral resolution, an early-type binary in the open cluster NGC 2362, and PX Vir, an F-type binary observed at high resolution for which the secondary companion had been detected in the infrared but not in the optical spectral range. It is shown that from standard-quality spectral datasets it is possible to detect the secondary star in systems in which the secondary contributes less than 0.5–1.0% of the total flux.
Optical observations of the Galactic supernova remnant HB9 and H II region G159.2+3.3
Authors: Li Jiang-Tao , Lu Li-Yuan , Mao Huiyang , Xia Zi-Qing , Chen Yang , Zhou Ping , Zhou Xin 
Published: August 2024

Context. We present multi-wavelength observations of the Galactic supernova remnant (SNR) HB9 and the H II region G159.2+3.3 apparently projected nearby, in order to study their properties and potential physical connections.
Aims. Confirming the physical connections between SNRs and H II regions is crucial to understanding their origin and interactions with the environment. Optical emission lines are powerful tools with which to measure the physical, chemical, and dynamical properties of the ionised gas, so could further help us to confirm such physical connections.
Methods. We present new optical narrow-band images of G159.2+3.3, as well as long-slit medium-resolution optical spectroscopy of both G159.2+3.3 and the SNR HB9 projected nearby. We compared these new data to archival multi-wavelength data to study the properties of the multi-phase interstellar medium in and around these two objects.
Results. HB9 is bright in γ-rays, but the γ-ray morphology is centrally filled and most of it is not clearly associated with the surrounding molecular clouds. There is a weak apparent connection of HB9 to the infrared bright enclosing shell of G159.2+3.3 in the γ-ray. The diffuse Balmer line has an almost identical morphology to the radio emission in G159.2+3.3, indicating they are both thermal in origin. Using medium-band high-resolution optical spectra from selected regions of the southeast (SE) shell of HB9 and G159.2+3.3, we found the radial velocity dispersion of HB9 along the slit to be significantly higher than the full width at half maximum of the lines. In contrast, these two values are both smaller and comparable to each other in G159.2+3.3. This indicates that the gas in HB9 may have additional global motion triggered by the SNR shock. The [N II] λ6583 Å/Hα line ratio of both objects can be interpreted with photo-ionisation by hot stars or low-velocity shocks, except for the post-shock region in the SE shell of HB9, where the elevated [N II]/Hα line ratio suggests a contribution from shock ionisation. The measured electron density from the [S II] 6716/6730 line ratio is significantly lower in the brighter G159.2+3.3 compared to the SE shell of HB9.
Conclusions. Our density estimate suggests that G159.2+3.3, although appearing brighter and more compact, is likely located at a much larger distance than HB9, so the two objects have no physical connections, unless the shock compressed gas in HB9 has a significantly lower filling factor.
Spatial and Socioeconomic Patterns of Mental Health and Healthcare
Utilization in Cologne, Germany
Authors: Poppe Adriana , Ansmann Lena , Meyer Ingo , Pförtner Timo-Kolja 
Published: August 2024

Abstract
Background Children and adolescents are significantly tied to their
family's socioeconomic position and living environment. Neighbourhood and
the living environment have been identified as potential risk factors for mental
disorders in this age group.
Aim of the Study The aim of the study was to investigate the distribution
of mental and behavioural disorders (prevalence) and the provision of mental
health services for children and adolescents aged 0–19 years in the city of
Cologne. In particular, the study aimed to examine the association of these
factors with area deprivation and the availability of mental health services
covered by statutory health insurance. Finally, possible spatial variations in
these aspects were analysed.
Method Claims data of children and adolescents aged 0 to 19 years included
in four statutory health insurance of the year 2021 were analysed. A deprivation
index using data on the level of the ZIP code area was calculated. Analyses were
carried out descriptively, using ordinary least squares (OLS) and geographically
weighted regression (GWR).
Results The prevalence of mental and behavioural disorders in children and
adolescents varied across ZIP code areas, with higher rates in the northern,
southern, and eastern parts of the city. The results indicated that the use of
services by male children and adolescents with a prevalent diagnosis of mental
and behavioural disorders was higher in areas with a higher density of
healthcare providers. However, prevalence was on the whole lower in areas with a
higher density of healthcare providers. In addition, the density of health care
providers was higher in the city centre with comparatively lower
deprivation.
Conclusion These results indicate inadequate access to care for children
and young people outside the city centre. However, due to the heterogeneity of
the population in these areas, this study provides only preliminary insights.
Data with a finer geographic resolution are needed for further research in order
to analyse the association further.