Globular clusters in the inner Galaxy classified from dynamical orbital criteria

Globular clusters (GCs) are the most ancient stellar systems in the Milky Way. Therefore, they play a key role in the understanding of the early chemical and dynamical evolution of our Galaxy. Around 40 per cent of them are placed within ∼4 kpc from the Galactic centre. In that region, all Galactic components overlap, making their disentanglement a challenging task. With GaiaData Release 2, we have accurate absolute proper motions for the entire sample of known GCs that have been associated with the bulge/bar region. Combining them with distances, from RR Lyrae when available, as well as radial velocities from spectroscopy, we can perform an orbital analysis of the sample, employing a steady Galactic potential with a bar. We applied a clustering algorithm to the orbital parameters apogalactic distance and the maximum vertical excursion from the plane, in order to identify the clusters that have high probability to belong to the bulge/bar, thick disc, inner halo, or outer halo component. We found that ∼30 per cent of the clusters classified as bulge GCs based on their location are just passing by the inner Galaxy, they appear to belong to the inner halo or thick disc component, instead. Most GCs that are confirmed to be bulge GCs are not following the bar structure and are older than the epoch of the bar formation

Ages of the bulge globular clusters NGC 6522 and NGC 6626 (M28) from HST proper-motion-cleaned color–magnitude diagrams

Bulge globular clusters (GCs) with metallicities [Fe/H]−1.0 and blue horizontal branches are candidates to harbor the oldest populations in the Galaxy. Based on the analysis of HST proper-motion-cleaned color–magnitude diagrams in filters F435W and F625W, we determine physical parameters for the old bulge GCs NGC 6522 and NGC 6626 (M28), both with well-defined blue horizontal branches. We compare these results with similar data for the inner halo cluster NGC 6362. These clusters have similar metallicities (−1.3[Fe/H]−1.0) obtained from high-resolution spectroscopy. We derive ages, distance moduli, and reddening values by means of statistical comparisons between observed and synthetic fiducial lines employing likelihood statistics and the Markov chain Monte Carlo method. The synthetic fiducial lines were generated using α-enhanced BaSTI and Dartmouth stellar evolutionary models, adopting both canonical (Y∼0.25) and enhanced (Y∼0.30–0.33) helium abundances. RR Lyrae stars were employed to determine the HB magnitude level, providing an independent indicator to constrain the apparent distance modulus and the helium enhancement. The shape of the observed fiducial line could be compatible with some helium enhancement for NGC 6522 and NGC 6626, but the average magnitudes of RR Lyrae stars tend to rule out this hypothesis. Assuming canonical helium abundances, BaSTI and Dartmouth models indicate that all three clusters are coeval, with ages between ∼12.5 and 13.0 Gyr. The present study also reveals that NGC 6522 has at least two stellar populations, since its CMD shows a significantly wide subgiant branch compatible with 14%±2% and 86%±5% for first and second generations, respectively

High-resolution abundance analysis of four red giants in the globular cluster NGC 6558

Context. NGC 6558 is a bulge globular cluster with a blue horizontal branch (BHB), combined with a metallicity of [Fe/H] ≈ −1.0. It is similar to HP 1 and NGC 6522, which could be among the oldest objects in the Galaxy. Element abundances in these clusters could reveal the nature of the first supernovae. Aims. We aim to carry out detailed spectroscopic analysis for four red giants of NGC 6558, in order to derive the abundances of the light elements C, N, O, Na, Al, the α-elements Mg, Si, Ca, Ti, and the heavy elements Y, Ba, and Eu. Methods. High-resolution spectra of four stars with FLAMES-UVES at VLT UT2-Kueyen were analysed. Spectroscopic parameter-derivation was based on excitation and ionization equilibrium of Fe I and Fe II. Results. This analysis results in a metallicity of [Fe/H] = − 1.17 ± 0.10 for NGC 6558. We find the expected α-element enhancements in O and Mg with [O/Fe] = +0.40, [Mg/Fe] = +0.33, and low enhancements in Si and Ca. Ti has a moderate enhancement of [Ti/Fe] = +0.22. The r-element Eu appears very enhanced with a mean value of [Eu/Fe] = +0.63. The first peak s-elements Y and Sr are also enhanced, these results have however to be treated with caution, given the uncertainties in the continuum definition; the use of neutral species (Sr I, Y I), instead of the dominant ionized species is another source of uncertainty. Ba appears to have a solar abundance ratio relative to Fe. Conclusions. NGC 6558 shows an abundance pattern that could be typical of the oldest inner bulge globular clusters, together with the pattern in the similar clusters NGC 6522 and HP 1. They show low abundances of the odd-Z elements Na and Al, and of the explosive nucleosynthesis α-elements Si, Ca, and Ti. The hydrostatic burning α-elements O and Mg are normally enhanced as expected in old stars enriched with yields from core-collapse supernovae, and the iron-peak elements Mn, Cu, Zn show low abundances, which is expected for Mn and Cu, but not for Zn. Finally, the cluster trio NGC 6558, NGC 6522, and HP 1 have relatively high abundances of first-peak heavy elements, variable second-peak element Ba, and the r-element Eu is enhanced. The latter is particularly high in NGC 6558

Associated factors and treatment options for sleep bruxism in children: an umbrella review

Data on clinical management options for sleep bruxism in the primary dentition are inconclusive. This umbrella review aimed to synthesize the available evidence from systematic reviews (SRs) on the associated factors and treatment approaches for clinical management of sleep bruxism in children. A search was conducted in the MEDLINE/PubMed, Web of Science, Embase, and OpenGrey databases up to March 2022. SRs published on sleep bruxism in children containing data on associated factors or treatment outcomes were included. The AMSTAR-2 tool was used to assess the methodological quality of SRs. The search identified 444 articles, of which six were included. Sleep conditions, respiratory changes, personality traits, and psychosocial factors were the associated factors commonly identified. Treatments included psychological and pharmacological therapies, occlusal devices, physical therapy, and surgical therapy. All SRs included presented a high risk of bias. Overlapping of the included studies was considered very high. The best evidence available to date for the management of sleep bruxism in children is based on associated factors, with sleep duration and conditions, respiratory changes, as well as personality traits and psychosocial factors being the most important factors commonly reported by studies. However, there is currently insufficient evidence to make recommendations for specific treatment options

The Viscacha survey - II: Structure of star clusters in the Magellanic Clouds periphery

We provide a homogeneous set of structural parameters of 83 star clusters located at the periphery of the Small Magellanic Cloud (SMC) and the Large Magellanic Cloud (LMC). The clusters’ stellar density and surface brightness profiles were built from deep, AO assisted optical images, and uniform analysis techniques. The structural parameters were obtained from King and Elson et al. model fittings. Integrated magnitudes and masses (for a subsample) are also provided. The sample contains mostly low surface brightness clusters with distances between 4.5 and 6.5 kpc and between 1 and 6.5 kpc from the LMC and SMC centres, respectively. We analysed their spatial distribution and structural properties, comparing them with those of inner clusters. Half-light and Jacobi radii were estimated, allowing an evaluation of the Roche volume tidal filling. We found that: (i) for both MCs, the tidal radii are on average larger than those of inner clusters; (ii) the core radii dispersion tends to be greater for LMC clusters located towards the southwest, with position angles of ∼200 degrees and about ∼5 degrees from the LMC centre, i.e., those LMC clusters nearer to the SMC; (iii) the analysis of clusters with ages available revealed that the core radius evolution is similar to the one of inner clusters; (iv) Roche volumes are overfilled for SMC clusters with galactocentric distances closer than 3 kpc.Fil: Santos, Joao F. C.. Universidad de La Serena; Chile. Universidade Federal de Minas Gerais; BrasilFil: Maia, Francisco. Universidade Federal do Rio de Janeiro; BrasilFil: Dias, Bruno. Millennium Institute of Astrophysics; Chile. Universidad Andrés Bello; ChileFil: de O. Kerber, Leandro. Universidade Estadual de Santa Cruz; BrasilFil: Piatti, Andres Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bica, Eduardo. Universidade Federal do Rio Grande do Sul; BrasilFil: Angelo, Mateus S.. Centro Federal de Educacao Tecnológica de Minas Gerais; BrasilFil: Minniti, Dante. Universidad Andrés Bello; Chile. Millennium Institute of Astrophysics; Chile. Vatican Observatory; ItaliaFil: Pérez Villegas, Angeles. Universidade de Sao Paulo; BrasilFil: Roman Lopes, Alexandre. Universidad de La Serena; ChileFil: Westera, Pieter. Universidad Federal Do Abc; BrasilFil: Fraga, Luciano. Laboratorio Nacional de Astrofísica; BrasilFil: Quint, Bruno. Gemini Observatory; ChileFil: Sanmartim, David. Carnegie Institution of Washington; Chil

The VMC survey - XV : The Small Magellanic Cloud-Bridge connection history as traced by their star cluster populations

Date of Acceptance: 19/03/2015We present results based on YJKs photometry of star clusters located in the outermost, eastern region of the Small Magellanic Cloud (SMC). We analysed a total of 51 catalogued clusters whose colour-magnitude diagrams (CMDs), having been cleaned from field-star contamination, were used to assess the clusters' reality and estimate ages of the genuine systems. Based on CMD analysis, 15 catalogued clusters were found to be possible non-genuine aggregates. We investigated the properties of 80 per cent of the catalogued clusters in this part of the SMC by enlarging our sample with previously obtained cluster ages, adopting a homogeneous scale for all. Their spatial distribution suggests that the oldest clusters, log(t/yr) ≥ 9.6, are in general located at greater distances to the galaxy's centre than their younger counterparts - 9.0 ≤ log(t/yr) ≤ 9.4 - while two excesses of clusters are seen at log(t/yr) ~9.2 and log(t yr-1) ˜ 9.7. We found a trail of younger clusters which follow the wing/bridge components. This long spatial sequence does not only harbour very young clusters, log(t yr-1) ~7.3, but it also hosts some of intermediate ages, log(t/yr) ~9.1. The derived cluster and field-star formation frequencies as a function of age are different. The most surprising feature is an observed excess of clusters with ages of log(t/yr) < 9.0, which could have been induced by interactions with the LMC.Peer reviewedFinal Accepted Versio

UVES analysis of red giants in the bulge globular cluster NGC 6522

Context. NGC 6522 is a moderately metal-poor bulge globular cluster ([Fe/H] ~ −1.0), and it is a well-studied representative among a number of moderately metal-poor blue horizontal branch clusters located in the bulge. The NGC 6522 abundance pattern can give hints on the earliest chemical enrichment in the central Galaxy. Aims. The aim of this study is to derive abundances of the light elements C and N; alpha elements O, Mg, Si, Ca, and Ti; odd-Z elements Na and Al; neutron-capture elements Y, Zr, Ba, La, and Nd; and the r-process element Eu. We verify if there are first- and second-generation stars: we find clear evidence of Na–Al, Na–N, and Mg–Al correlations, while we cannot identify the Na–O anti-correlation from our data. Methods. High-resolution spectra of six red giants in the bulge globular cluster NGC 6522 were obtained at the 8m VLT UT2-Kueyen telescope with both the UVES and GIRAFFE spectrographs in FLAMES+UVES configuration. In light of Gaia data, it turned out that two of them are non-members, but these were also analysed. Spectroscopic parameters were derived through the excitation and ionisation equilibrium of Fe I and Fe II lines from UVES spectra. The abundances were obtained with spectrum synthesis. Comparisons of abundances derived from UVES and GIRAFFE spectra were carried out. Results. The present analysis combined with previous UVES results gives a mean radial velocity of vrhel = −15.62±7.7 km s−1 and a metallicity of [Fe/H] = −1.05 ± 0.20 for NGC 6522. Mean abundances of alpha elements for the present four member stars are enhanced with [O/Fe] = +0.38, [Mg/Fe] = ≈+0.28, [Si/Fe] ≈ +0.19, and [Ca/Fe] ≈ +0.13, together with the iron-peak element [Ti/Fe] ≈ +0.13, and the r-process element [Eu/Fe] = +0.40. The neutron-capture elements Y, Zr, Ba, and La show enhancements in the +0.08 < [Y/Fe] < +0.90, 0.11 < [Zr/Fe] < +0.50, 0.00 < [Ba/Fe] < +0.63, 0.00 < [La/Fe] < +0.45, and −0.10 < [Nd/Fe] < +0.70 ranges. We also discuss the spread in heavy-element abundances

Ages and metallicities of stellar clusters using S-PLUS narrow-band integrated photometry: the Small Magellanic Cloud

The Magellanic Clouds are the most massive and closest satellite galaxies of the Milky Way, with stars covering ages from a few Myr up to 13 Gyr. This makes them important for validating integrated light methods to study stellar populations and star-formation processes, which can be applied to more distant galaxies. We characterized a set of stellar clusters in the Small Magellanic Cloud (SMC), using the $\textit{Southern Photometric Local Universe Survey}$. This is the first age (metallicity) determination for 11 (65) clusters of this sample. Through its 7 narrow bands, centered on important spectral features, and 5 broad bands, we can retrieve detailed information about stellar populations. We obtained ages and metallicities for all stellar clusters using the Bayesian spectral energy distribution fitting code $\texttt{BAGPIPES}$. With a sample of clusters in the color range $-0.20 < r-z < +0.35$, for which our determined parameters are most reliable, we modeled the age-metallicity relation of SMC. At any given age, the metallicities of SMC clusters are lower than those of both the Gaia Sausage-Enceladus disrupted dwarf galaxy and the Milky Way. In comparison with literature values, differences are $\Delta$log(age)$\approx0.31$ and $\Delta$[Fe/H]$\approx0.41$, which is comparable to low-resolution spectroscopy of individual stars. Finally, we confirm a previously known gradient, with younger clusters in the center and older ones preferentially located in the outermost regions. On the other hand, we found no evidence of a significant metallicity gradient.Comment: 12 pages, 11 figure