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Abstract We present an open-source computational tool for the 2D simulation of the Diffusive-Logistic Growth (DLG) model. The r.recovery module offers a complete environment for the simulation of forestry regeneration in conservation areas and includes a built-in tool for calibration and validation of the model parameters through the use of standard and freely available satellite imagery. It was implemented as an add-on to the GRASS software, a largely applied open-source Geographic Information System (GIS). To illustrate its application, we present a complete case study of forest regeneration carried out in the Espigão Alto State Park (EASP), Brazil, from which we assess typical values of forest diffusion and growth rate parameters, along with the prognostics of forest density status for the coming decades. We observe that the r.recovery tool can be advantageously applied by forestry managers and policy-makers as a form of acquiring technical and scientifically-based information for strategy development and decision-making. Highlights • This research makes a state-of-the-art forestry modeling framework available for a large public. • The module can be coupled to hydrological models in long-term simulations. • The module is user-friendly and can enhance the efficiency and response time of forestry management processes. • A complete walkthrough is presented to illustrate the application of the module. • The module is open-source and freely available for download at http://modelagemambientaluffs.blogspot.com.br/. [ABSTRACT FROM AUTHOR]

Riparian buffer strips (RBS) play an important role in the conservation of water bodies. Yet to date the increasing degradation of riparian vegetation is a major concern due to the inherent risk it poses to quality and quantity of drinkable water. In turn, forest regeneration is known to be a process that evolves in a time-scale of years, such that the regeneration of a forested area after a perturbation can take several decades. In this context, the exploration of models of vegetation growth can contribute to the understanding and acknowledgement of diverse aspects of such phenoma. Further, from the standpoint of conservation projects, the application of models allows the assessment of different future scenarios resulting from the application of different management practices, thus allowing anticipating the likely outcomes of the management process. In this paper, we study the application of the diffusive-logistic model (DLG model) to the problem of forest regeneration. We concentrate in vegetation belonging to permanent preservation areas, such as RBS. The main contribution of this study is to propose and illustrate a thorough methodology applicable as auxiliary assessment and design tool for conservation projects. The study is developed in two steps. We build upon recent results that study on the performance of riparian buffer strips in the removal of nitrogen in agricultural catchments in which an Artificial Neural Network Ensemble (ANNE) was applied to evaluate the riparian buffer strip width needed to accomplish filtering of 90% of the residual nitrogen. On this basis, we calibrate and validate the parameters of the diffusive-logistic model of forest growth to estimate the evolution of regeneration in riparian buffer strips, considering the buffer widths obtained by the ANNE. We implement the solution in GPGPU (General Purpose Graphics Processing Unit) and then simulate for forty years ahead to verify the likely effect of conservation upon the riparian buffer strips in the watershed. The results of calibration and validation show that the diffusive-logistic model provides a rather accurate temporal and spatial account of forest regeneration. The application of the model to a case study of the Ligeiro River watershed, Brazil, shows that the model can provide valuable insights for decision-making in the context of environmental conservation and management. [ABSTRACT FROM AUTHOR]

In this work, we investigate the properties of 18 embedded clusters (ECs). The sample includes 11 previously known clusters and we report the discovery of seven ECs on WISE images, thus complementing our recent list of 437 new clusters. The main goal is to use such clusters to shed new light on the Galactic structure by tracing the spiral arms with cluster distances. Our results favour a four-armed spiral pattern tracing three arms, Sagitarius-Carina, Perseus, and the Outer arm. The Sagitarius-Carina spiral arm is probed in the borderline of the third and fourth quadrants at a distance from the Galactic Centre of d1 ~ 6.4 kpc adopting R⊙ = 7.2 kpc, or d2 ~ 7.2 kpc for R⊙ = 8.0 kpc. Most ECs in our sample are located in the Perseus arm that is traced in the second and third quadrants and appear to be at Galactocentric distances in the range d1 = 9-10.5 kpc or d2 = 9.8-11.3 kpc. Dolidze 25, Bochum 2, and Camargo 445 are located in the Outer arm that extends along the second and third Galactic quadrants with a distance from the Galactic Centre in the range of d1 = 12.5-14.5 kpc or d2 = 13.5-15.5 kpc. We find further evidence that in the Galaxy ECs are predominantly located within the thin disc and along spiral arms. They are excellent tools for tracing these Galactic features and therefore new searches for ECs can contribute to a better understanding of the Galactic structure. We also report an EC aggregate located in key italicthe Perseus arm. [ABSTRACT FROM AUTHOR]

We present a simple approach for obtaining robust values of astrophysical parameters from the observed colour-magnitude diagrams (CMDs) of star clusters. The basic inputs are the Hess diagram built with the photometric measurements of a star cluster and a set of isochrones covering wide ranges of age and metallicity. In short, each isochrone is shifted in apparent distance modulus and colour excess until it crosses over the maximum possible Hess density. Repeating this step for all available isochrones leads to the construction of the solution map, in which the optimum values of age and metallicity - as well as foreground/background reddening and distance from the Sun - can be searched for. Controlled tests with simulated CMDs show that the approach is efficient in recovering the input values. We apply the approach to the open clusters M 67, NGC 6791 and NGC 2635, which are characterized by different ages, metallicities and distances from the Sun. [ABSTRACT FROM AUTHOR]

ABSTRACT We investigate the nature of 48 low-level stellar overdensities (from Froebrich, Scholz and Raftery catalogue - FSR07) projected towards the Galactic anticentre and derive fundamental parameters for the confirmed clusters, thus improving the open cluster (OC) census in that direction. Parameters are derived with field-star decontaminated photometry, colour-magnitude filters and stellar radial density profiles. Among the 48 targets, we identified 18 star clusters, six previously studied OCs and seven probable clusters that require deeper photometry to establish the nature. We discovered seven new clusters, six of them forming an association of clusters with BPI 14, FSR 777, Kronberger 1 and Stock 8 in the region of the nebula IC 417 and related to the Aur OB2 association, and one embedded in the nebula Sh2-229. We also derive parameters for these three non-FSR07 clusters, because they are important in determining the structure of the Galactic anticentre. Thus, 58 objects are analysed in this work and we could derive fundamental parameters for 28 of them. The scenario in the IC 417 star-forming region is consistent with a sequential event. FSR 888 and FSR 890 are embedded in Sh2-249 within the Gem OB1 association. According to the distance derived for these clusters and those in the association of clusters, both Aur OB2 and Gem OB1 are located in the Perseus arm. [ABSTRACT FROM AUTHOR]

ABSTRACT The initial and present-day mass functions (ICMFs and PDMFs, respectively) of the Galactic globular clusters (GCs) are constructed based on their observed luminosities, the stellar evolution and dynamical mass-loss processes, and the mass-to-light ratio ( M/ L). Under these conditions, a Schechter-like ICMF is evolved for approximately a Hubble time and converted into a luminosity function (LF), which requires finding the values of five free parameters: the mean GC age (), the dissolution time-scale of a 105-M⊙ cluster (τ5), the exponential truncation mass () and two M/ L parametrizing constants. This is achieved by minimizing the residuals between the evolved and observed LFs, with the minimum residuals and realistic parameters obtained with M/ Ls that increase with luminosity (or mass). The optimum PMDFs indicate a total stellar mass of ∼4 × 107 M⊙ still bound to GCs, representing ∼15 per cent of the mass in clusters at the beginning of the gas-free evolution. The corresponding ICMFs resemble the scale-free MFs of young clusters and molecular clouds observed in the local Universe, while the PDMFs follow closely a lognormal distribution with a turnover at M⊙. For most of the GC mass range, we find an M/ L lower than usually adopted, which explains the somewhat low . Our results confirm that the M/ L increases with cluster mass (or luminosity), and suggest that GCs and young clusters share a common origin in terms of physical processes related to formation. [ABSTRACT FROM AUTHOR]

ABSTRACT We present an approach that improves the search for reliable astrophysical parameters (e.g. age, mass and distance) of differentially reddened, pre-main-sequence-rich star clusters. It involves simulating conditions related to the early-cluster phases, in particular the differential and foreground reddenings, and internal age spread. Given the loose constraints imposed by these factors, the derivation of parameters based only on photometry may be uncertain, especially for the poorly populated clusters. We consider a wide range of cluster (i) mass and (ii) age, and different values of (iii) distance modulus, (iv) differential and (v) foreground reddenings. Photometric errors and their relation with magnitude are also taken into account. We also investigate how the presence of unresolved binaries affect the derived parameters. For each set of (i)-(v) we build the corresponding model Hess diagram, and compute the root mean squared residual with respect to the observed Hess diagram. The parameters that produce the minimum residuals between model and observed Hess diagrams are searched by exploring the full parameter space of (i)-(v) by means of brute force, which may be time consuming but efficient. Control tests show that an adequate convergence is achieved allowing for solutions with residuals 10 per cent higher than the absolute minimum. Compared to a colour-magnitude diagram containing only single stars, the presence of 100 per cent of unresolved binaries has little effect on cluster age, foreground and differential reddenings; significant differences show up in the cluster mass and distance from the Sun. Our approach proves to be successful in minimizing the subjectiveness when deriving fundamental parameters of young star clusters. [ABSTRACT FROM AUTHOR]

ABSTRACT We investigate the nature of 14 embedded clusters (ECs) related to a group of four H ii regions, Sh2-235, Sh2-233, Sh2-232 and Sh2-231, in the giant molecular cloud G174 + 2.5. Projected towards the Galactic anticentre, these objects are possible examples of the collect-and-collapse scenario. We derive astrophysical parameters ( age, reddening, distance, core and cluster radii) for the ECs and investigate the relationship between these parameters. Parameters are derived with field-star-decontaminated 2MASS colour-magnitude diagrams (CMDs) and stellar radial density profiles. The CMDs of these young clusters are characterized by a poorly populated main sequence and a significant number of pre-main-sequence stars, affected by differential reddening. The ECs are KKC 11, FSR 784, Sh2-235 East2, Sh2-235 Cluster, Sh2-233 SE Cluster, BDSB 73, Sh2-235B Cluster, BDSB 72, BDSB 71, Sh2-232 IR Cluster, PCS 2, and the newly found clusters CBB 1 and CBB 2. We were able to derive fundamental parameters for all ECs in the sample. Structural parameters are derived for FSR 784, Sh2-235 Cluster and Sh2-235 East2. [ABSTRACT FROM AUTHOR]

ABSTRACT This paper investigates the star formation rate (SFR) in the solar neighbourhood. First, we build the local age distribution function (ADF) with an updated sample of 442 star clusters located at less than 1 kpc from the Sun. Next, we define the SFR, compute the individual mass evolution of a population of artificial clusters covering the broad range of parameters observed in actual clusters, and assume 100 M ⊙ as the low-mass limit for effective cluster observation. This leads to a simulated ADF, which is compared to the low-noise solar neighbourhood ADF. The best match corresponds to a non-constant SFR presenting two conspicuous excesses for ages ≤9 Myr and between 220-600 Myr (the local starburst). The average SFR is , corresponding to the average surface SFR . These values are consistent with the SFR inferred from embedded clusters (ECs), but much lower (≲16 per cent) than that implied by field stars. Both the local starburst and the recent star formation period require to be described. The simulations show that 91.2 ± 2.7 per cent of the clusters created in the solar neighbourhood do not survive the first 10 Myr, which is consistent with the rate of EC dissolution. [ABSTRACT FROM AUTHOR]

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We study how the spectral fitting of galaxies, in terms of light fractions, derived in one spectral region translates into another region, by using results from evolutionary synthesis models. In particular, we examine propagation dependencies on evolutionary population synthesis (EPS) models (, , Maraston and ), age, metallicity and stellar evolution tracks over the near-ultraviolet-near-infrared (NUV-NIR, 3500 Å to 2.5 μm) spectral region. Our main results are as follows: as expected, young ( Myr) stellar population fractions derived in the optical cannot be directly compared to those derived in the NIR, and vice versa. In contrast, intermediate to old age ( Myr) fractions are similar over the whole spectral region studied. The metallicity has a negligible effect on the propagation of the stellar population fractions derived from NUV to NIR. The same applies to the different EPS models, but restricted to the range between 3800 and 9000 Å. However, a discrepancy between /Maraston and / models occurs in the NIR. Furthermore, the initial mass function is not important for the synthesis propagation. Compared to synthesis results, our propagation predictions agree at ∼95 per cent confidence level in the optical, and ∼85 per cent in the NIR. In summary, spectral fitting performed in a restricted spectral range should not be directly propagated from the NIR to the UV/optical, or vice versa. We provide equations and an on-line form [panchromatic averaged stellar population (PaASP)] to be used for this purpose. [ABSTRACT FROM AUTHOR]

Excitability is a generic prediction for an optically injected semiconductor laser. However, the details of the phenomenon differ depending on the type of device in question. For quantum-well lasers very complicated multipulse trajectories can be found, while for quantum-dot lasers the situation is much simpler. Experimental observations show the marked differences in the pulse shapes while theoretical considerations reveal the underlying mechanism responsible for the contrast, identifying, the increased stability of quantum-dot lasers to perturbations as the root. [ABSTRACT FROM AUTHOR]

We derive fundamental, structural and photometric parameters of 15 overlooked Ruprecht (hereafter Ru) star clusters by means of Two-Micron All-Sky Survey photometry and field-star decontamination. Ru 1, 10, 23, 26, 27, 34, 35, 37, 41, 54, 60, 63, 66 and 152 are located in the third Galactic quadrant, while Ru 174 is in the first. With the constraints imposed by the field-decontaminated colour–magnitude diagrams and stellar radial density profiles (RDPs), we derive ages in the range 400 Myr – 1 Gyr, except for the older Ru 37, with ∼3 Gyr. Distances from the Sun are within . The RDPs are well-defined and can be described by a King-like profile for most of the radial range, except for Ru 23, 27, 41, 63 and 174, which present a conspicuous stellar density excess in the central region. The clusters dwell between (or close to) the Perseus and Sagittarius-Carina arms. We derive evidence in favour of cluster size increasing with distance to the Galactic plane ( ZGP), which is consistent with a low frequency of tidal stress associated with high- regions. The clusters are rather faint even in the near-infrared, with apparent integrated J magnitudes within , while their absolute magnitudes are . Extrapolation of the relation between and , derived for globular clusters, suggests that they are low-luminosity optical clusters, with . [ABSTRACT FROM AUTHOR]

We investigate the degree of spatial correlation among extended structures in the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC). To this purpose, we work with subsamples characterized by different properties such as age and size, taken from the updated catalogue of Bica et al. or gathered in the present work. The structures are classified as star clusters or non-clusters (basically, nebular complexes and their stellar associations). The radius distribution functions follow power laws with slopes and maximum radius ( Rmax) that depend on object class (and age). Non-clusters are characterized by and , while young clusters (age ≲10 Myr) have and and old ones (age ≳600 Myr) have and . Young clusters present a high degree of spatial self-correlation and, especially, correlate with star-forming structures, which does not occur with the old ones. This is consistent with the old clusters having been heavily mixed up, since their ages correspond to several LMC and SMC crossing times. On the other hand, with ages corresponding to fractions of the respective crossing times, the young clusters still trace most of their birthplace structural pattern. Also, small clusters , as well as small non-clusters , are spatially self-correlated, while their large counterparts of both classes are not. The above results are consistent with a hierarchical star formation scenario for the LMC and SMC. [ABSTRACT FROM AUTHOR]

Teutsch 145 and Teutsch 146 are shown to be open clusters (OCs) orbiting well inside the solar circle, a region where several dynamical processes combine to disrupt most OCs on a time-scale of a few 108 yr. BVI photometry from the GALILEO telescope is used to investigate the nature and derive the fundamental and structural parameters of the optically faint and poorly known OCs Teutsch 145 and 146. These parameters are computed by means of field-star-decontaminated colour–magnitude diagrams and stellar radial density profiles (RDPs). Cluster mass estimates are made based on the intrinsic mass functions (MFs). We derive the ages and , and the distances from the Sun and , respectively, for Teutsch 145 and 146. Their integrated apparent and absolute magnitudes are and 13.3 and and −5.3. The MFs (detected for stars with ) have slopes similar to Salpeter's initial mass function. Extrapolated to the H-burning limit, the MFs would produce total stellar masses of , typical of relatively massive OCs. Both OCs are located deep into the inner Galaxy and close to the Crux–Scutum arm. Since cluster-disruption processes are important, their primordial masses must have been higher than the present-day values. The conspicuous stellar density excess observed in the innermost bin of both RDPs might reflect the dynamical effects induced by a few of external tidal stress. [ABSTRACT FROM AUTHOR]

We investigate the nature of four young and low-mass open clusters (OCs) located in the second and third quadrants with near-infrared Two-Micron All Sky Survey (2MASS) photometry (errors ). After field decontamination, the colour–magnitude diagrams (CMDs) display similar morphologies: a poorly populated main sequence (MS) and a dominant fraction of pre-MS (PMS) stars somewhat affected by differential reddening. Pismis 5, vdB 80 and BDSB 96 have MS ages within , while the MS of NGC 1931 is old. However, non-instantaneous star formation is implied by the wider (∼20 Myr) PMS age spread. The cluster masses derived from MS+PMS stars are low, within , with mass functions (MFs) significantly flatter than Salpeter's initial mass function (IMF). Distances from the Sun are within 1.0–2.4 kpc, and the visual absorptions are in the range . From the stellar radial density profiles (RDPs), we find that they are small , especially Pismis 5 with and . Except for the irregular and cuspy inner regions of NGC 1931 and Pismis 5, the stellar RDPs follow a King-like profile. At ∼10 Myr, central cusps – which in old clusters appear to be related to advanced dynamical evolution – are probably associated with a star formation and/or molecular cloud fragmentation effect. Despite the flat MFs, vdB 80 and BDSB 96 appear to be typical young, low-mass OCs. NGC 1931 and especially Pismis 5, with irregular RDPs, low cluster mass and flat MFs, do not appear to be in dynamical equilibrium. Both may be evolving into OB associations and/or doomed to dissolution in a few 107 yr. [ABSTRACT FROM AUTHOR]

With Two-Micron All-Sky Survey (2MASS) photometry and proper motions, Bonatto et al. suggested that FSR 1767 is a globular cluster (GC), while with J and K NTT/SOFI photometry Froebrich, Meusinger & Scholz concluded that it is not a star cluster. In this study, we combine previous and new evidence that are consistent with a GC. For instance, we show that the horizontal branch (HB) and red giant branch (RGB) stars, besides sharing a common proper motion, have radial density profiles that consistently follow the King's law independently. Reddening maps around FSR 1767 are built using the bulge RGB as reference and also Schlegel's extinction values to study local absorptions. Both approaches provide similar maps and show that FSR 1767 is not located in a dust window, which otherwise might have produced the stellar overdensity. Besides, neighbouring regions of similar reddening as FSR 1767 do not present the blue HB stars that are a conspicuous feature in the colour–magnitude diagram of FSR 1767. We report the presence of a compact group of stars located in the central parts of FSR 1767. It appears to be a detached post-collapse core, similar to those of other nearby low-luminosity GCs projected towards the bulge. We note that while the NTT/SOFI photometry of the star cluster FSR 1716 matches perfectly that from 2MASS, it shows a considerable offset for FSR 1767. We discuss the possible reasons why both photometries differ. We confirm our previous structural and photometric fundamental parameters for FSR 1767, which are consistent with a GC. [ABSTRACT FROM AUTHOR]

The very young open cluster (OC) NGC 2244 in the Rosette Nebula was studied with field-star-decontaminated Two-Micron All-Sky Survey (2MASS) photometry, which shows the main-sequence (MS) stars and an abundant pre-MS (PMS) population. Fundamental and structural parameters were derived with colour–magnitude diagrams (CMDs), stellar radial density profiles (RDPs) and mass functions (MFs). Most previous studies centred NGC 2244 close to the bright K0V star 12 Monocerotis, which is not a cluster member. Instead, the near-infrared RDP indicates a pronounced core near the O5 star HD 46150. We derive an age within 1–6 Myr, an absorption , a distance from the Sun (≈1.5 kpc outside the solar circle), an MF slope and a total (MS+PMS) stellar mass of . Its RDP is characterized by the core and cluster radii and , respectively. Departure from dynamical equilibrium is suggested by the abnormally large core radius and the marked central stellar excess. We also investigate the elusive neighbouring OC NGC 2239, which is low mass , young rather absorbed , and located in the background of NGC 2244 at . Its RDP follows a King-like function of and . The MF slope, , is essentially Salpeter's initial mass function. NGC 2244 is probably doomed to dissolution in a few 107 yr. Wide-field extractions and field-star decontamination increase the stellar statistics and enhance both CMDs and RDPs, which is essential for faint and bright star clusters. [ABSTRACT FROM AUTHOR]

The combination of several mass-decreasing processes may critically affect the structure of open clusters (OCs), to the point that most dissolve into the field in a time-scale shorter than ≈1 Gyr. Therefore, as is observed, old OCs should be sparse within the Galaxy. These mass-decreasing processes can only be quantifiably examined given the derivation of the fundamental parameters, age, distance and mass, for a sample of old OCs. In this paper we focus on four candidate old star clusters, namely, LK 1, LK 10, FSR 1521 and FSR 1555. The first two clusters, discovered by Le Duigou & Knödlseder, are projected towards the Cygnus association, whilst the remaining two have been detected in the fourth quadrant as cluster candidates from stellar overdensities by Froebrich, Scholz & Raftery. To analyse the target clusters we construct near-infrared colour–magnitude diagrams (CMDs) and derive stellar radial density profiles (RDPs). The CMDs are constructed using Two Micron All-Sky Survey (2MASS) J, H and Ks bands, and the intrinsic morphologies of the target OCs within these diagrams are revealed by applying a field-star decontamination algorithm. Fundamental parameters are estimated with Padova isochrones built for the 2MASS filters. We derive extinctions to the objects within the range , which makes them suitable for the near-infrared analysis, ages within 1.0–2.0 Gyr, and distances from the Sun within 1.4–4.5 kpc. These distances, in conjunction with the positions in the sky, place the present four OCs close to the solar circle . For LK 10 our photometry reaches a depth ≈3 mag below the main-sequence turn off, from which we derive a relatively steep mass function slope when compared to the Salpeter value . LK 10 is a rather massive old OC, with a mass within , for stars in the observed magnitude range and the extrapolation to , respectively. The mass estimated in the restricted magnitude range for the remaining, more distant OCs is within . However, similarity with the CMD morphology and red clump of LK 10 suggests that they may be as massive as LK 10. The RDPs are well represented by a King-like function, except LK 10, which has a central cusp suggesting post-core collapse. Structurally, LK 1, FSR 1521 and FSR 1555 are similar to a sample of nearby OCs of comparable age. [ABSTRACT FROM AUTHOR]

Abstract: We derive fundamental parameters of the embedded cluster DBSB 48 in the southern nebula Hoffleit 18 and the very young open cluster Trumpler 14, by means of deep JHK s infrared photometry. We build colour–magnitude and colour–colour diagrams to derive reddening and age, based on main sequence and pre-main sequence distributions. Radial stellar density profiles are used to study cluster structure and guide photometric diagram extractions. Field-star decontamination is applied to uncover the intrinsic cluster sequences in the diagrams. Ages are inferred from K-excess fractions. A prominent pre-main sequence population is present in DBSB 48, and the K-excess fraction f K =55±6% gives an age of 1.1±0.5Myr. A mean reddening of was found, corresponding to A V =8.2±0.3. The cluster CMD is consistent with the far kinematic distance of 5kpc for Hoffleit 18. For Trumpler 14 we derived similar parameters as in previous studies in the optical, in particular an age of 1.7±0.7Myr. The fraction of stars with infrared excess in Trumpler 14 is f K =28±4%. Despite the young ages, both clusters are described by a King profile with core radii R core =0.46±0.05pc and R core =0.35±0.04pc, respectively, for DBSB 48 and Trumpler 14. Such cores are smaller than those of typical open clusters. Small cores are probably related to the cluster formation and/or parent molecular cloud fragmentation. In DBSB 48, the magnitude extent of the upper main sequence is ΔK s ≈2mag, while in Trumpler 14 it is ΔK s ≈5mag, consistent with the estimated ages. [Copyright &y& Elsevier]

We update the Small Magellanic Cloud (SMC), Bridge and Large Magellanic Cloud (LMC) catalogues of extended objects that were constructed by members of our group from 1995 to 2000. In addition to the rich subsequent literature for the previous classes, we now also include H i shells and supershells. A total of 9305 objects were cross-identified, while our previous catalogues amounted to 7900 entries, an increase of ≈12 per cent. We present the results in subcatalogues containing 1445 emission nebulae, 3740 star clusters, 3326 associations and 794 H i shells and supershells. Angular and apparent size distributions of the extended objects are analysed. We conclude that the objects, in general, appear to respond to tidal effects arising from the LMC, SMC and Bridge. Number-density profiles extracted along directions parallel and perpendicular to the LMC bar, can be described by two exponential-discs. A single exponential-disc fits the equivalent SMC profiles. Interestingly, when angular-averaged number-densities of most of the extended objects are considered, the profiles of both Clouds do not follow an exponential-disc. Rather, they are best described by a tidally truncated, core/halo profile, despite the fact that the Clouds are clearly disturbed discs. On the other hand, the older star clusters taken isolately, distribute as an exponential disc. The present catalogue is an important tool for the unambiguous identification of previous objects in current CCD surveys and to establish new findings. [ABSTRACT FROM AUTHOR]

We report the discovery of a new open cluster (OC) in the Galaxy at and . Its field includes the planetary nebula (PN) PK 167−0.1. We study the possible associations of the PN/OC pairs NGC 2818/2818A, NGC 2438/M 46 (NGC 2437), PK 6+2.5/NGC 6469, as well as of the PN PK 167−0.1 with New Cluster 1. The analyses are based on near-infrared colour–magnitude diagrams (CMDs) and stellar radial density profiles. NGC 6469 is located in a heavily contaminated bulge field. The CMD morphology, especially for the latter two cases, is defined with a field-star decontamination algorithm applied to the 2MASS J, H and Ks photometry. Field decontamination for the OCs NGC 2818A and M 46 produced better defined CMDs and more accurate cluster parameters than in the literature. Those pieces of evidence point to M 46 as physically associated with the PN NGC 2438. The same occurs for the OC NGC 2818A and the PN NGC 2818; however, previous radial velocity arguments indicate that they are not associated. The OC NGC 6469 does not appear to be associated with the PN PK 6+2.5, which probably belongs to the bulge. Finally, the distance of the OC New Cluster 1 is consistent with a physical association with the PN PK 167−0.1. [ABSTRACT FROM AUTHOR]

We analyse 20 star cluster candidates projected mostly in the bulge direction . The sample contains all candidates in that sector classified by Froebrich, Scholz & Raftery with quality flags denoting high probability of being star clusters. Bulge contamination in the colour–magnitude diagrams (CMDs) is in general important, while at lower Galactic latitudes disc stars contribute as well. Properties of the candidates are investigated with Two Micron All Sky Survey (2MASS) CMDs and stellar radial density profiles (RDPs) built with field star decontaminated photometry. To uncover the nature of the structures we decontaminate the CMDs from field stars using tools that we previously developed to deal with objects in dense fields. We confirm in all cases excesses in the RDPs with respect to the background level, as expected from the method the candidates were originally selected. CMDs and RDPs taken together revealed six open clusters, five uncertain cases that require deeper observations, while nine objects are possibly field density fluctuations. [ABSTRACT FROM AUTHOR]

We study the nature of the globular cluster (GC) candidates FSR 1603 and FSR 1755 selected from the catalogue of Froebrich, Scholz & Raftery. Their properties are investigated with Two-Micron All-Sky Survey field-star decontaminated photometry, which is used to build colour–magnitude diagrams (CMDs) and stellar radial density profiles. FSR 1603 has the open cluster Ruprecht 101 as optical counterpart, and we show it to be a massive intermediate-age cluster. Relevant parameters of FSR 1603 are the age ≈1 Gyr, distance from the Sun , Galactocentric distance , core radius , mass function slope , observed stellar mass (for stars with mass in the range ) and a total (extrapolated to ) stellar mass . FSR 1755, on the other hand, is not a populous cluster. It may be a sparse young cluster embedded in the H ii region Sh 2-3, subject to an absorption , located at . Important field-star contamination, spatially variable heavy dust obscuration, even in Ks, and gas emission characterize its field. A nearly vertical, sparse blue stellar sequence shows up in the CMDs. [ABSTRACT FROM AUTHOR]

Star clusters projected on to dense stellar fields in general require field-star (FS) decontamination to confirm their nature and derive intrinsic photometric and structural fundamental parameters. This work focuses on the open clusters (OCs) or candidates NGC 5715, Lyngå 4, Lyngå 9, Trumpler 23, Trumpler 26 and Czernik 37 which are projected within and , against crowded bulge and/or disc fields. To tackle these difficult objects we develop a colour–magnitude diagram FS-decontamination algorithm based on 2MASS J, ( J− H) and data, and respective uncertainties, to detect cluster star excesses over the background. On the other hand, colour–magnitude filters are used to build stellar radial density profiles and mass functions. The results convey compelling evidence that Lyngå 9 and Czernik 37 are intermediate-age OCs, and their fundamental parameters are measured for the first time. Trumpler 23 is a particularly challenging object, since besides high background level, its field presents variable absorption in near-infrared bands. We confirm it to be an intermediate-age OC. Trumpler 26 is studied in more detail than in previous works, while NGC 5715 and Lyngå 4 have fundamental parameters determined for the first time. These OCs are located 0.9–1.6 kpc within the solar circle, with ages similar to that of the Hyades. Structurally, they are well described by King profiles. In all cases, core and limiting radii are significantly smaller than those of nearby OCs outside the solar circle. We test the effect of background levels on cluster radii determinations by means of simulations. They indicate that for central clusters, radii may be underestimated by about 10–20 per cent, which suggests that the small sizes measured for the present sample reflect as well intrinsic properties related to dynamical evolution effects. The objects probably have been suffering important tidal effects that may have accelerated dynamical evolution, especially in Czernik 37, the innermost object. [ABSTRACT FROM AUTHOR]

We analyse the nature of a sample of stellar overdensities that we found projected on the Carina complex. This study is based on the Two Micron All Sky Survey photometry and involves the photometry decontamination of field stars, elaboration of intrinsic colour-magnitude diagrams [CMDs; J × (J - Ks)], colour-colour diagrams (J - H) × (H - Ks), and radial density profiles, in order to determine the structure and the main astrophysical parameters of the best candidates. The verification of an overdensity as an embedded cluster requires a CMD consistent with a PMS content and MS stars, if any. From these results, we are able to verify if they are, in fact, embedded clusters. The results were, in general, rewarding: in a sample of 101 overdensities, the analysis provided 15 candidates, of which three were previously catalogued as clusters (CCCP-Cl 16, Treasure Chest, and FSR 1555), and the 12 remaining are discoveries that provided significant results, with ages not above 4.5Myr and distances compatible with the studied complex. The resulting values for the differential reddening of most candidates were relatively high, confirming that these clusters are still (partially or fully) embedded in the surrounding gas and dust, as a rule within a shell. Histograms with the distribution of the masses, ages, and distances were also produced, to give an overview of the results. We conclude that all the 12 newly found embedded clusters are related to the Carina complex. [ABSTRACT FROM AUTHOR]

The globular cluster (GC) nature of the recently catalogued candidate FSR 1767 is established in the present work. It turns out to be the closest GC so far detected in the Galaxy. The nature of this object is investigated by means of 2MASS colour–magnitude diagrams (CMDs), the stellar radial density profile (RDP) and proper motions (PM). The properties are consistent with an intermediate-metallicity GC with a well-defined turnoff (TO), red giant branch (RGB) and blue horizontal branch (HB). The distance of FSR 1767 from the Sun is , and it is located at the Galactocentric distance . With the space velocity components , FSR 1767 appears to be a Palomar-like GC with , which currently lies ≈57 pc below the Galactic plane. The RDP is well represented by a King profile with the core and tidal radii and , respectively, with a small half-light radius . The optical absorption is moderate for an infrared GC, , which together with its central direction and enhanced contamination explains why it has so far been overlooked. [ABSTRACT FROM AUTHOR]

We report the discovery of 652 star clusters, stellar groups and candidates in the Milky Way with Wide-field Infrared Survey Explorer (WISE). Most of the objects are projected close to Galactic plane and are embedded clusters. The present sample complements a similar study (Paper I) which provided 437 star clusters and alike. We find evidence that star formation processes span a wide range of sizes, from populous dense clusters to small compact embedded ones, sparse stellar groups or in relative isolation. The present list indicates multiple stellar generations during the embedded phase, with giant molecular clouds collapsing into several clumps composing an embedded cluster aggregate.We investigate the field star decontaminated colour-magnitude diagrams and radial density profiles of nine cluster candidates in the list, and derive their parameters, confirming them as embedded clusters. [ABSTRACT FROM AUTHOR]

We obtained Southern Astrophysical Research telescope B and V photometry of 14 star clusters and two associations in the Bridge tidal structure connecting the Large and Small Magellanic Cloud (LMC and SMC). These objects are used to study the formation and evolution of star clusters and associations under tidal stresses from the Clouds. Typical star clusters in the Bridge are not richly populated and have in general relatively large diameters (30-35 pc), being larger than Galactic counterparts of similar age. Ages and other fundamental parameters are determined with field-star decontaminated photometry. A self-consistent approach is used to derive parameters for the most-populated sample cluster NGC 796 and two young CMD templates built with the remaining Bridge clusters. We find that the clusters are not coeval in the Bridge. They range from approximately a few Myr (still related to optical H II regions and WISE and Spitzer dust emission measurements) to about 100-200 Myr. The derived distance moduli for the Bridge objects (1h56m < α < 2h28m) suggests that the Bridge is a structure connecting the LMC farside in the east to the foreground of the SMC to the west. Most of the present clusters are part of the tidal dwarf candidate D 1, which is associated with an H I overdensity. We find further evidence that the studied part of the Bridge is evolving into a tidal dwarf galaxy, decoupling from the Bridge. [ABSTRACT FROM AUTHOR]

Molecular clouds at very high latitude (b > 60°) away from the Galactic plane are rare and in general are expected to be non-star-forming. However, we report the discovery of two embedded clusters (Camargo 438 and Camargo 439) within the high-latitude molecular cloud HRK 81.4-77.8 using WISE. Camargo 439 with Galactic coordinates ℓ = 81°.11 and b = -77°. 84 is an ~2 Myr embedded cluster (EC) located at a distance from the Sun of CLQ = 5.09 ± 0.47 kpc. Adopting the distance of the Sun to the Galactic Centre R8857; = 7.2 kpc, we derive for Camargo 439 a Galactocentric distance of RGC = 8.70 ± 0.26 kpc and a vertical distance from the plane of -4.97 ± 0.46 kpc. Camargo 438 at ℓ = 79°.66 and b = -78&#176.86 presents similar values. The derived parameters for these two ECs put HRK 81.4-77.8 in the halo at a distance from the Galactic Centre of ~8.7 kpc and ~5.0 kpc from the disc. Star clusters provide the only direct means to determine the high-latitude molecular cloud distances. The present study shows that the molecular cloud HRK 81.4-77.8 is currently forming stars, apparently an unprecedented event detected so far among high-latitude clouds. We carried out a preliminary orbit analysis. It shows that these ECs are the most distant known ECs from the plane and both cloud and clusters are probably falling ballistically from the halo on to the Galactic disc, or performing a flyby. [ABSTRACT FROM AUTHOR]

We employed field star decontaminated Two Micron All Sky Survey photometry to study four nearby optical embedded clusters -- Collinder 34, NGC 3293, NGC 3766 and NGC 6231 -- obtaining deep colour-magnitude diagrams and stellar radial density profiles. We found what seem to be pre-main sequences detached in different amounts from main sequences in these diagrams. The structural analysis of each cluster revealed different radial distributions for these two sequences. We argued that the detached evolutionary sequences in our sample may be evidence of sequential star formation. Finally, we compared the sample cluster parameters with those of other young clusters in the literature and point out evidence that NGC 3766 and NGC 6231 might be evolving to OB associations. [ABSTRACT FROM AUTHOR]

Context. NGC6357 is an active star-forming region located in the Sagittarius arm that displays several star clusters, which makes it a very interesting target to investigate star formation and early cluster evolution. Aims. We explore NGC6357 with the VISTA Variables in the Vía Láctea (VVV) photometry of seven embedded clusters (ECs), and one open cluster projected in the outskirts of the complex. Methods. Photometric and structural properties (age, reddening, distance, core, and total radii) of the star clusters were derived. VVV saturated stars were replaced by their 2MASS counterparts. Field-decontaminated VVV photometry was used to analyse colour– magnitude diagrams (CMDs) and stellar radial density profiles and determine astrophysical parameters. Results. We report the discovery of four ECs and one intermediate-age cluster in the complex area. We derive a revised distance estimate for NGC6357 of 1.78 ± 0.1 kpc based on the cluster CMD morphologies. Of the ECs, one contains the binary star WR93, while the remaining ones are dominated by pre-main sequence stars, young stellar objects, and/or and have a developed main sequence. These features reflect a significant age spread among the clusters. Evidence is found that the relatively populous cluster Pismis 24 hosts two subclusters. [ABSTRACT FROM AUTHOR]

Abstract: This work is devoted to the study of the interaction between pulses of electromagnetic radiation and space-charge waves in laser-plasmas settings. We analyse modes depending only on the co-moving coordinate of the beam frame, but make no a priori assumption on the longitudinal-to-transverse aspect ratio of the pulses. The model thus constructed allows us to investigate regimes where transverse and longitudinal length scales of the pulses are comparable. Resonant and nonresonant excitations of space-charge modes are analyzed and the endurance of trains of solitons against transverse effects is clarified. [Copyright &y& Elsevier]

Context. Fundamental parameters characterizing the end-state of intermediate-mass stars may be constrained by discovering planetary nebulae (PNe) in open clusters (OCs). Cluster membership may be exploited to establish the distance, luminosity, age, and physical size for PNe, and the intrinsic luminosity and mass of its central star. Aims. Four potential PN-OC associations were investigated to assess the cluster membership for the PNe. Methods. Radial velocities were measured from intermediate-resolution optical spectra, complemented with previous estimates in the literature. When the radial velocity study supported the PN/OC association, we analyzed whether other parameters (e.g., age, distance, reddening, central star brightness) were consistent with this conclusion. Results. Our measurements imply that the PNe VBe 3 and HeFa 1 are not members of the OCs NGC5999 and NGC6067, respectively, and that they very likely belong to the background bulge population. Conversely, consistent radial velocities indicate that NGC2452/NGC 2453 could be associated, but our results are not conclusive so additional observations are warranted. Finally, we demonstrate that all the available information point to He 2-86 being a young, highly internally obscured PN member of NGC4463. New near-infrared photometry acquired via the Vista Variables in the Via Lactea ESO public survey was used in tandem with existing UBV photometry to measure the distance, reddening, and age of NGC4463, finding d = 1.55 ± 0.10 kpc, E(B - V) = 0.41 ± 0.02, and t = 65 ± 10 Myr, respectively. The same values should be adopted for the PN if the proposed cluster membership is confirmed. [ABSTRACT FROM AUTHOR]

Context. The ESO Public Survey "VISTA Variables in the Vía Láctea" (VVV) provides deep multi-epoch infrared observations for an unprecedented 562 sq. degrees of the Galactic bulge, and adjacent regions of the disk. Nearly 150 new open clusters and cluster candidates have been discovered in this survey. Aims. This is the second in a series of papers about young, massive open clusters observed using the VVV survey. We present the first study of six recently discovered clusters. These clusters contain at least one newly discovered Wolf-Rayet (WR) star. Methods. Following the methodology presented in the first paper of the series, wide-field, deep JHKs VVV observations, combined with new infrared spectroscopy, are employed to constrain fundamental parameters for a subset of clusters. Results. We find that the six studied stellar groups are real young (2-7 Myr) and massive (between 0.8 and 2.2 × 103 M⊙) clusters. They are highly obscured (AV ∼ 5-24 mag) and compact (1-2 pc). In addition to WR stars, two of the six clusters also contain at least one red supergiant star, and one of these two clusters also contains a blue supergiant. We claim the discovery of 8 new WR stars, and 3 stars showing WR-like emission lines which could be classified WR or OIf. Preliminary analysis provides initial masses of ∼30-50 M⊙ for the WR stars. Finally, we discuss the spiral structure of the Galaxy using the six new clusters as tracers, together with the previously studied VVV clusters. [ABSTRACT FROM AUTHOR]

ABSTRACT It is currently widely accepted that open star clusters and stellar associations result from the evolution of embedded star clusters. Parameters such star formation efficiency, time-scale of gas removal and velocity dispersion can be determinants of their future as bound or unbound systems. Finding objects at an intermediate evolution state can provide constraints to model the embedded cluster evolution. In the H ii region IC 1396, Trumpler 37 is an extended young cluster that presents characteristics of an association. We employed the Two Micron All Sky Survey (2MASS) photometry for analysing its structure and stellar content, and determining its astrophysical parameters. We also analysed 11 bright-rimmed clouds in IC 1396 in order to search for young infrared star clusters, and the background open star cluster Teutsch 74, to verify whether it has any contribution to the observed stellar density profile of Trumpler 37. The derived parameters and comparison with template objects from other studies lead us to conclude that Trumpler 37, rather than as a star cluster, will probably emerge from its molecular cloud as an OB association. [ABSTRACT FROM AUTHOR]

Embedded clusters are formed in molecular clouds where massive stars can produce H ii regions. The detailed evolutionary connection between embedded and open clusters, and the origin of associations are still to be discovered. There appears to be a high infant mortality rate among embedded clusters, and the few survivors evolve to open clusters. We study the colour–magnitude diagrams (CMDs) and structure of the star clusters related to the Sh2-132 H ii region using the Two-Micron All-Sky Survey (2MASS) data base. The fundamental and structural parameters of clusters are determined using main-sequence and pre-main-sequence isochrones and stellar radial density profiles. We report on the discovery of four clusters. One of these is projected a few diameters away from the optical cluster, Teutsch 127, and appears to be deeply embedded, seen only in the infrared. Evidence is found that we are witnessing the dynamical transition from an embedded to an open cluster. An additional cluster is also close to Teutsch 127 and might be associated with a bow-shock. We also study the CMD and structure of the open cluster, Berkeley 94, in Sh2-132, and a new cluster that is projected in the outskirts of the complex. Finally, we have searched for star clusters around the two known Wolf–Rayet stars in the complex. One of these appears to be related to a compact cluster. Finally, the present analyses suggest early dynamical evolution for young star clusters. [ABSTRACT FROM AUTHOR]

We employ the recently installed near-infrared Multi-Conjugate Adaptive Optics demonstrator (MAD) to determine the basic properties of a newly identified, old and distant, Galactic open cluster (FSR 1415). The MAD facility remarkably approaches the diffraction limit, reaching a resolution of 0.07 arcsec (in K), that is also uniform in a field of ∼1.8 arcmin in diameter. The MAD facility provides photometry that is 50 per cent complete at . This corresponds to about 2.5 mag below the cluster main-sequence turn-off. This high-quality data set allows us to derive an accurate heliocentric distance of 8.6 kpc, a metallicity close to solar and an age of ∼2.5 Gyr. On the other hand, the deepness of the data allows us to reconstruct (completeness-corrected) mass functions (MFs) indicating a relatively massive cluster, with a flat core MF. The Very Large Telescope/MAD capabilities will therefore provide fundamental data for identifying/analysing other faint and distant open clusters in the Galaxy III and IV quadrants. [ABSTRACT FROM AUTHOR]

The stellar population, metallicity distribution and ionized gas in the elliptical galaxies NGC 6868 and 5903 are investigated in this paper by means of long-slit spectroscopy and stellar population synthesis. Lick indices in both galaxies present a negative gradient indicating an overabundance of Fe, Mg, Na and TiO in the central parts with respect to the external regions. We found that Mg2 correlates both with Fe i λ5270 and Fe i λ5335, suggesting that these elements probably underwent the same enrichment process in NGC 6868. However, only a marginal correlation of Mg2 and Fe i λ5270 occurs in NGC 5903. The lack of correlation between computed galaxy mass and the Mg2 gradient suggests that these elliptical galaxies were formed by merger events. The stellar population synthesis shows the presence of at least two populations with ages of 13 and 5 Gyr old in both galaxies. We have estimated the metallicity of the galaxies using single-aged stellar population (SSP) models. The central region of NGC 6868 presents a deficiency of alpha elements with respect to iron and solar metallicity. The external parts present a roughly uniform distribution of ratios and metallicities ranging from and solar. A similar conclusion applies to NGC 5903. Concerning the emitting gas conspicuously detected in NGC 6868, we test three hypotheses as ionizing source: an H ii region, post-AGB (asymptotic giant branch) stars and an active galactic nucleus (AGN). Diagnostic diagrams involving the ratios and indicate that values measured in the central region of NGC 6868 are typical of LINERs (Low-Ionization Nuclear Emission-Line Regions). Together with the stellar population synthesis, this result suggests that the main source of gas ionization in NGC 6868 is non-thermal, produced by a low-luminosity AGN, probably with some contribution of shocks to explain ionization at distances of from the nucleus. [ABSTRACT FROM AUTHOR]

This project is a massive near-infrared (NIR) search for variable stars in highly reddened and obscured open cluster (OC) fields projected on regions of the Galactic bulge and disk. The search is performed using photometric NIR data in the J -, H - and K s - bands obtained from the Vista Variables in the Vía Láctea (VVV) Survey. We performed in each cluster field a variability search using Stetson’s variability statistics to select the variable candidates. Later, those candidates were subjected to a frequency analysis using the Generalized Lomb-Scargle and the Phase Dispersion Minimization algorithms. The number of independent observations range between 63 and 73. The newly discovered variables in this study, 157 in total in three different known OCs, are classified based on their light curve shapes, periods, amplitudes and their location in the corresponding color-magnitude ( J − K s , K s ) and color-color ( H − K s , J − H ) diagrams. We found 5 possible Cepheid stars which, based on the period-luminosity relation, are very likely type II Cepheids located behind the bulge. Among the newly discovered variables, there are eclipsing binaries, δ Scuti, as well as background RR Lyrae stars. Using the new version of the Wilson & Devinney code as well as the “Physics Of Eclipsing Binaries” (PHOEBE) code, we analyzed some of the best eclipsing binaries we discovered. Our results show that these studied systems turn out to be ranging from detached to double-contact binaries, with low eccentricities and high inclinations of approximately 80°. Their surface temperatures range between 3500 K and 8000 K. [ABSTRACT FROM AUTHOR]

We report our study of features at the observed red end of the white dwarf cooling sequences for three Galactic globular clusters: NGC 6397, 47 Tucanae and M 4. We use deep colour- magnitude diagrams constructed from archival Hubble Space Telescope (Advanced Camera for Surveys) to systematically investigate the blue turn at faint magnitudes and the age determinations for each cluster. We find that the age difference between NGC 6397 and 47 Tuc is 1.98+0.44 -0.26 Gyr, consistent with the picture that metal-rich halo clusters were formed later than metal-poor halo clusters. We self-consistently include the effect of metallicity on the progenitor age and the initial-to-final mass relation. In contrast with previous investigations that invoked a single white dwarf mass for each cluster, the data show a spread of white dwarf masses that better reproduce the shape and location of the blue turn. This effect alone, however, does not completely reproduce the observational data - the blue turn retains some mystery. In this context, we discuss several other potential problems in the models. These include possible partial mixing of H and He in the atmosphere of white dwarf stars, the lack of a good physical description of the collision-induced absorption process and uncertainties in the opacities at low temperatures. The latter are already known to be significant in the description of the cool main sequence. Additionally, we find that the present-day local mass function of NGC 6397 is consistent with a top-heavy type, while 47 Tuc presents a bottom-heavy profile. [ABSTRACT FROM AUTHOR]

We report the discovery of two new variable stars in the metal-poor globular cluster NGC 288, found by means of time series CCD photometry. We classified the new variables as SX Phoenicis (SX Phe) due to their characteristic fundamental mode periods (1.02 ± 0.01 and 0.69 ± 0.01 h), and refine the period estimates for other six known variables. SX Phe stars are known to follow a well-defined period–luminosity (P–L) relation and, thus, can be used for determining distances; they are more numerous than RR Lyraes in NGC 288. We obtain the P–L relation for the fundamental mode MV = (−2.59 ± 0.18) log P0(d) + (−0.34 ± 0.24) and for the first-overtone mode MV = (−2.59 ± 0.18) log P1(d) + (0.50 ± 0.25). Multichromatic isochrone fits to our UBV colour–magnitude diagrams, based on the Dartmouth Stellar Evolution Database, provide 〈[Fe/H]〉 = −1.3 ± 0.1, E(B − V) = 0.02 ± 0.01 and absolute distance modulus (m − M)0 = 14.72 ± 0.01 for NGC 288. [ABSTRACT FROM AUTHOR]

Context. VISTA Variables in the Vía Láctea (VVV) is one of six ESO Public Surveys using the 4 meter Visible and Infrared Survey Telescope for Astronomy (VISTA). The VVV survey covers the Milky Way bulge and an adjacent section of the disk, and one of the principal objectives is to search for new star clusters within previously unreachable obscured parts of the Galaxy. Aims. The primary motivation behind this work is to discover and analyze obscured star clusters in the direction of the inner Galactic disk and bulge. Methods. Regions of the inner disk and bulge covered by the VVV survey were visually inspected using composite JHKS color images to select new cluster candidates on the basis of apparent overdensities. DR1, DR2, CASU, and point spread function photometry of 10 × 10 arcmin fields centered on each candidate cluster were used to construct color-magnitude and color-color diagrams. Follow-up spectroscopy of the brightest members of several cluster candidates was obtained in order to clarify their nature. Results. We report the discovery of 58 new infrared cluster candidates. Fundamental parameters such as age, distance, and metallicity were determined for 20 of the most populous clusters. [ABSTRACT FROM AUTHOR]

In this study, we present a detailed study of mass segregation in the globular cluster NGC 6397. First, we carry out a photometric analysis of projected European Southern Observatory (ESO)–Very Large Telescope (VLT) data (between 1 and 10 arcmin from the cluster centre), presenting the luminosity function corrected by completeness. The luminosity function shows a higher density of bright stars near the central region of the data with respect to the outer region. We calculate a deprojected model (covering the whole cluster), estimating a total number of 193 000 ± 19 000 stars. The shapes of the surface brightness and density-number profiles versus the radial coordinate r (instead of the projected coordinate R) lead to a decreasing luminosity and thus mass for an average star, up to 1 arcmin, quantifying the mass segregation. The deprojected model does not show evidence of mass segregation outside this region. [ABSTRACT FROM PUBLISHER]

Andrews-Lindsay 1 is a pertinent open cluster because it may host the planetary nebula (PN) PHR 1315-6555, yet ambiguities linger concerning its fundamental parameters (>50% scatter). New multiband BVJHW1-4 photometry for cluster and field stars, in concert with observations of recently discovered classical Cepheids, were used to constrain the reddening and velocity-distance profiles along the sightline. That analysis yielded the following parameters for the cluster: E(J − H) = 0.24 ± 0.03, d = 10.0 ± 0.4 kpc (dJH = 9.9 ± 0.6 kpc, dBV = 10.1 ± 0.5 kpc), and log τ = 8.90 ± 0.15. The steep velocity-distance gradient along ℓ ~ 305° indicates that two remote objects sharing spatial and kinematic parameters (i.e., PHR 1315-6555 and Andrews-Lindsay 1) are associated, thus confirming claims that the PN is a cluster member. The new distance for PHR 1315-6555 is among the most precise established yet for a Galactic PN (σ/d = 4%). [ABSTRACT FROM AUTHOR]

Context. Young massive clusters are key to map the Milky Way's structure, and near-infrared large area sky surveys have contributed strongly to the discovery of new obscured massive stellar clusters. Aims. We present the third article in a series of papers focused on young and massive clusters discovered in the VVV survey. This article is dedicated to the physical characterization of VVVCL086, using part of its OB-stellar population. Methods. We physically characterized the cluster using JHKS near-infrared photometry from ESO public survey VVV images, using the VVV-SkZ pipeline, and near-infrared K-band spectroscopy, following the methodology presented in the first article of the series. Results. Individual distances for two observed stars indicate that the cluster is located at the far edge of the Galactic bar. These stars, which are probable cluster members from the statistically field-star decontaminated CMD, have spectral types between O9 and B0V. According to our analysis, this young cluster (1.0 Myr < age < 5.0 Myr) is located at a distance of 11+5-6 kpc, and we estimate a lower limit for the cluster total mass of (2.8+1.6-1.4) . 10³ M☉. It is likely that the cluster contains even earlier and more massive stars. [ABSTRACT FROM AUTHOR]

New and existing X-ray, UBVJHKsW(1-4), and spectroscopic observations were analyzed to constrain fundamental parameters for M25, NGC 7790, and dust along their sight-lines. The star clusters are of particular importance because they host the classical Cepheids USgr, CF Cas, and the visual binary Cepheids CEa and CEb Cas. Precise results from the multiband analysis, in tandem with a comprehensive determination of the Cepheids' period evolution (dP/dt) from ∼140 years of observations, helped to resolve concerns raised regarding the clusters and their key Cepheid constituents. Specifically, the distances derived for members of M25 and NGC7790 are 630 ± 25 pc and 3.40 ± 0.15 kpc, respectively. [ABSTRACT FROM AUTHOR]

Cepheids are key to establishing the cosmic distance scale. Therefore it's important to assess the viability of QZ Nor, V340 Nor, and GU Nor as calibrators for Leavitt's law via their purported membership in the open cluster NGC 6067. The following suite of evidence confirms that QZ Nor and V340 Nor are members of NGC 6067, whereas GU Nor likely lies in the foreground: (i) existing radial velocities for QZ Nor and V340 Nor agree with that established for the cluster ( $-39.4\pm0.2(\sigma_{\bar {x}}) \pm1.2 (\sigma)~\mbox{km/s}$) to within 1 km/s, whereas GU Nor exhibits a markedly smaller value; (ii) a steep velocity-distance gradient characterizes the sight-line toward NGC 6067, thus implying that objects sharing common velocities are nearly equidistant; (iii) a radial profile constructed for NGC 6067 indicates that QZ Nor is within the cluster bounds, despite being 20′ from the cluster center; (iv) new BVJH photometry for NGC 6067 confirms the cluster lies d=1.75±0.10 kpc distant, a result that matches Wesenheit distances computed for QZ Nor/V340 Nor using the Benedict et al. (Astron. J. 133:1810, , HST parallaxes) calibration. QZ Nor is a cluster Cepheid that should be employed as a calibrator for the cosmic distance scale. [ABSTRACT FROM AUTHOR]

We study the kinematics and excitation mechanisms of H2 and [Fe ii] lines in a sample of 67 emission-line galaxies with Infrared Telescope Facility SpeX near-infrared (0.8–2.4 μm) spectroscopy together with new photoionization models. H2 emission lines are systematically narrower than narrow-line region lines, suggesting that the two are, very likely, kinematically disconnected. The new models and emission-line ratios show that the thermal excitation plays an important role not only in active galactic nuclei but also in star-forming galaxies. The importance of the thermal excitation in star-forming galaxies may be associated with the presence of supernova remnants close to the region emitting H2 lines. This hypothesis is further supported by the similarity between vibrational and rotational temperatures of H2. We confirm that the diagram involving the line ratios H2 2.121 μm/Brγ and [Fe ii] 1.257 μm/Paβ is an efficient tool for separating emission-line objects according to their dominant types of activities. We suggest new limits to the line ratios in order to discriminate between the different types of nuclear activities. [ABSTRACT FROM AUTHOR]