The Seven Sisters DANCe. I. Empirical isochrones, Luminosity and Mass Functions of the Pleiades cluster

The DANCe survey provides photometric and astrometric (position and proper motion) measurements for approximately 2 millions unique sources in a region encompassing $\approx$80deg$^{2}$ centered around the Pleiades cluster. We aim at deriving a complete census of the Pleiades, and measure the mass and luminosity function of the cluster. Using the probabilistic selection method described in Sarro+2014, we identify high probability members in the DANCe ($i\ge$14mag) and Tycho-2 ($V\lesssim$12mag) catalogues, and study the properties of the cluster over the corresponding luminosity range. We find a total of 2109 high probability members, of which 812 are new, making it the most extensive and complete census of the cluster to date. The luminosity and mass functions of the cluster are computed from the most massive members down to $\approx$0.025M$_{\odot}$. The size, sensitivity and quality of the sample result in the most precise luminosity and mass functions observed to date for a cluster. Our census supersedes previous studies of the Pleiades cluster populations, both in terms of sensitivity and accuracy.Comment: Language Edition Done. Final version to be published in A&A. Tables will be published at CDS. Meanwhile, they can be requested to H. Bouy (hbouy -at- cab . inta - csic . es

The effect of spatial resolution on optical and near-IR studies of stellar clusters: Implications for the origin of the red excess

Recent ground based near-IR studies of stellar clusters in nearby galaxies have suggested that young clusters remain embedded for 7-10Myr in their progenitor molecular cloud, in conflict with optical based studies which find that clusters are exposed after 1-3Myr. Here, we investigate the role that spatial resolution plays in this apparent conflict. We use a recent catalogue of young ($5000$~\msun) clusters in the nearby spiral galaxy, M83, along with Hubble Space Telescope (HST) imaging in the optical and near-IR, and ground based near-IR imaging, to see how the colours (and hence estimated properties such as age and extinction) are affected by the aperture size employed, in order to simulate studies of differing resolution. We find that the near-IR is heavily affected by the resolution, and when aperture sizes $>40$~pc are used, all young/blue clusters move red-ward in colour space, which results in their appearance as heavily extincted clusters. However, this is due to contamination from nearby sources and nebular emission, and is not an extinction effect. Optical colours are much less affected by resolution. Due to the larger affect of contamination in the near-IR, we find that, in some cases, clusters will appear to show near-IR excess when large ($>20$~pc) apertures are used. Our results explain why few young ($<6$~Myr), low extinction (\av < 1~mag) clusters have been found in recent ground based near-IR studies of cluster populations, while many such clusters have been found in higher resolution HST based studies. Additionally, resolution effects appear to (at least partially) explain the origin of the near-IR excess that has been found in a number of extragalactic YMCs.Comment: 8 pages, 5 figures, accepted for publication in MNRA

Clues on the Galactic evolution of sulphur from star clusters

(Abridged) The abundances of alpha-elements are a powerful diagnostic of the star formation history and chemical evolution of a galaxy. Sulphur, being moderately volatile, can be reliably measured in the interstellar medium (ISM) of damped Ly-alpha galaxies and extragalactic HII regions. Measurements in stars of different metallicity in our Galaxy can then be readily compared to the abundances in external galaxies. Such a comparison is not possible for Si or Ca that suffer depletion onto dust in the ISM. Furthermore, studying sulphur is interesting because it probes nucleosynthetic conditions that are very different from those of O or Mg. The measurements in star clusters are a reliable tracers of the Galactic evolution of sulphur. We find NLTE=6.11+/-0.04 for M 4, NLTE=7.17+/-0.02 for NGC 2477, and NLTE=7.13+/-0.06 for NGC 5822. For the only star studied in Trumpler 5 we find A(S)NLTE=6.43+/-0.03 and A(S)LTE=6.94+/-0.05. Our measurements show that, by and large, the S abundances in Galactic clusters trace reliably those in field stars. The only possible exception is Trumpler 5, for which the NLTE sulphur abundance implies an [S/Fe] ratio lower by roughly 0.4 dex than observed in field stars of comparable metallicity, even though its LTE sulphur abundance is in line with abundances of field stars. Moreover the LTE sulphur abundance is consistent only with the abundance of another alpha-element, Mg, in the same star, while the low NLTE value is consistent with Si and Ca. The S abundances in our sample of stars in clusters imply that the clusters are chemically homogeneous for S within 0.05 dex.Comment: A&A in pres

A super lithium-rich red-clump star in the open cluster Trumpler 5

Context. The existence of lithium-rich low-mass red giant stars still represents a challenge for stellar evolution models. Stellar clusters are privileged environments for this kind of investigation. Aims. To investigate the chemical abundance pattern of the old open cluster Trumpler\,5, we observed a sample of four red-clump stars with high-resolution optical spectrographs. One of them (#3416) reveals extremely strong lithium lines in its spectrum. Methods. One-dimensional, local thermodynamic equilibrium analysis was performed on the spectra of the observed stars. A 3D-NLTE analysis was performed to derive the lithium abundance of star #3416. Results. Star #3416 is super Li-rich with A(Li)=3.75\,dex. The lack of $^6$Li enrichment ($^6$Li/$^7$Li$<$2%), the low carbon isotopic ratio ($^{12}$C/$^{13}$C=14$\pm$3), and the lack of evidence for radial velocity variation or enhanced rotational velocity ($v\sin i = 2.8\,$\kms) all suggest that lithium production has occurred in this star through the Cameron & Fowler mechanism. Conclusions. We identified a super Li-rich core helium-burning, red-clump star in an open cluster. Internal production is the most likely cause of the observed enrichment. Given the expected short duration of a star's Li-rich phase, enrichment is likely to have occurred at the red clump or in the immediately preceding phases, namely during the He-flash at the tip of the red giant branch (RGB) or while ascending the brightest portion of the RGB.Comment: 7 pages, 2 figures. Accepted for publication in A&A Letter

Drug-Induced Homicide: Challenges and Strategies in Criminal Defense

Nearing the end of its second decade, the crisis of fatal opioid-involved overdoses in the United States has gone from bad to worse. In 2017, approximately 72,000 people died of a drug overdose in the United States. Overdose is now the leading cause of death for people under fifty. There is broad agreement that reducing opioid overdose deaths requires wider distribution of the opioid antidote naloxone, rapid scale-up in evidence-based treatment, and reducing the stigma associated with substance use and addiction. However, progress on these and other vital public health interventions remains abysmally slow. Meanwhile, there is a new and growing trend in enforcing drug-induced homicide and similar laws in overdose death cases. Originally intended to implicate dealers in accidental drug overdoses, such charges were rarely brought until recent years. Just since 2010, however, media coverage of prosecutions based on such provisions has spiked at least threefold, from 363 in 2011 to 1,178 in 2016

Stigma as a fundamental hindrance to the United States opioid overdose crisis response.

Alexander Tsai and co-authors discuss the role of stigma in responses to the US opioid crisis

Automated search for star clusters in large multiband surveys: II. Discovery and investigation of open clusters in the Galactic plane

Automated search for star clusters in J,H,K_s data from 2MASS catalog has been performed using the method developed by Koposov et. al (2008). We have found and verified 153 new clusters in the interval of the galactic latitude -24 < b < 24 degrees. Color excesses E(B-V), distance moduli and ages were determined for 130 new and 14 yet-unstudied known clusters. In this paper, we publish a catalog of coordinates, diameters, and main parameters of all the clusters under study. A special web-site available at http://ocl.sai.msu.ru has been developed to facilitate dissemination and scientific usage of the results.Comment: 9 pages, 3 tables, 5 figures, accepted to Astronomy Letter

Properties of the solar neighbor WISE J072003.20-084651.2

The severe crowding towards the Galactic plane suggests that the census of nearby stars in that direction may be incomplete. Recently, Scholz reported a new M9 object at an estimated distance d~7 pc (WISE J072003.20-084651.2; hereafter WISE0720) at Galactic latitude b=2.3 degr. Our goals are to determine the physical characteristics of WISE0720, its kinematic properties, and to address the question if it is a binary object, as suggested in the discovery paper. Optical and infrared spectroscopy from the Southern African Large Telescope and Magellan, respectively, and spectral energy distribution fitting were used to determine the spectral type of WISE0720. The measured radial velocity, proper motion and parallax yielded its Galactic velocities. We also investigated if WISE0720 may show X-ray activity based on archival data. Our spectra are consistent with spectral type L0+/-1. We find no evidence for binarity, apart for a minor 2-sigma level difference in the radial velocities taken at two different epochs. The spatial velocity of WISE0720 does not connect it to any known moving group, instead it places the object with high probability in the old thin disk or in the thick disk. The spectral energy distribution fit hints at excess in the 12 and 22 micron WISE bands which may be due to a redder companion, but the same excess is visible in other late type objects, and it more likely implies a shortcoming of the models (e.g., issues with the effective wavelengths of the filters for these extremely cool objects, etc.) rather than a disk or redder companion. The optical spectrum shows some Halpha emission, indicative of stellar activity. Archival X-ray observations yield no detection.Comment: A&A, accepted; 9 pages, 6 figure

Developing predictive models value of freight cars

В статье приведен анализ основных методик рационального использования вагонного парка железных дорог. Установлено, что в настоящее время на железнодорожном транспорте в области автоматизации перевозочного процесса не уделяется особого внимания факторам, которые влияют на элемент оборота грузового вагона. Освещены основные понятия нейронных сетей. Разработана математическая модель прогнозирования оборота грузового вагона. Результаты моделирования позволяют оценить внутреннюю адекватность модели прогнозирования, которые количественно оценивают точность расчетов.У статті наведено аналіз основних методик раціонального використання вагонного парку залізниць. Встановлено, що в даний час на залізничному транспорті в області автоматизації перевізного процесу не приділяється особливої уваги факторам, які впливають на елемент обігу вантажного вагона. Висвітлено основні поняття нейронних мереж. Розроблено математичну модель прогнозування обігу вантажного вагона. Результати моделювання дозволяють оцінити внутрішню адекватність моделі прогнозування, які кількісно оцінюють точність розрахунків.The article presents the analysis of the main methods rational use rolling stock railways. It was found that at present the railways in the transportation process automation does not pay particular attention to factors that affect the element turnover of freight wagon. Basic concepts neural networks. A mathematical model for predicting turnover of freight wagon. The simulation results allow to evaluate the adequacy of internal forecasting models that quantitatively assess the accuracy calculations. This structure neural network will ensure compliance with the requirements operational forecasts regarding the value turnover car based on the comparison and synthesis of the input parameters. Thus, after the construction of such a network and provide input parameter vector is obtained predictive value turnover of freight wagon. As noted earlier, the construction forecasting models perform turnover of freight cars by DN and the railway as a whole must be based on analysis statistical and dynamic data on the implementation high- quality performance their elements