1,723,784 research outputs found
Bayesian characterization of the young open cluster NGC 6383 using HDBSCAN and Gaia DR3
Get PDFEste estudio se centra en determinar las características del joven cúmulo abierto NGC 6383. Para lograrlo, se utiliza el algoritmo de agrupamiento HDBSCAN para identificar los miembros potenciales del cúmulo basándose en los movimientos propios y los paralajes utilizando Gaia Data Release 3. Se obtienen varios parámetros de NGC 6383, como el tidal radius, el radio del núcleo, la distancia mediante paralaje y ajuste de isócronas, el movimiento propio promedio, la edad, la metalicidad y otros relevantes. Para realizar este análisis, utilizamos una extensión de Monte Carlo Hamiltoniano, el No-U-Turn Sampler. Los resultados de este análisis señalan que NGC 6383 es un cúmulo abierto muy joven (≈ 1 — 4 Myr), con una distancia de ≈ 1.1 kpc.This study focuses on determining the characteristics of the young open cluster NGC 6383. To achieve this, the HDBSCAN clustering algorithm is utilized to identify potential cluster members based on proper motions and parallaxes from Gaia Data Release 3. Various parameters of NGC 6383, such as tidal radius, core radius, distance through parallax and isochrone-fitting, proper motion, age, metallicity, and relevant others, are assessed. To perform this analysis, we utilize an extension of Hamiltonian Monte Carlo, the No-U-Turn Sampler. The results of this analysis point out that NGC 6383 is a very young open cluster (≈ 1 — 4 Myr), with a distance of ≈ 1.1 kpc.Asociación Argentina de Astronomí
The Colour Magnitude Diagram of The Galactic Cluster NGC 6383
No full textAbstract. Almost all the stars in a circular area with a radius of about 12 min. of arc, were measured photometrically down to V="13".80 mag., using plates obtained with the Uppsala Schmidt telescope Mt. Stromlo and the Schmidt telescope at Lembang. The photographic measurement generally confirm Enggen's remarkable result that NGC 6383 is a very young cluster, similar to NGC 2264. Groups stars lying on different parts of the colour magnitude diagram NGC 6383, are discussed in connection with Herbig's idea about non-coevalness of stars in stellar cluster. Ichtisar. Hampir semua bintang dalam sebuah daerah bundar dengan djari2 kira2 12 menit busur, telah diukur setjara photometris sampai V = 13.80 magn., dengan menggunakan katja2 potret jang didapatkan dengan teropong Schmidt Uppsala di Observatorium Mt. Stromlo dan teropong Schmidt di Lembang. Kumpulan2 bintang jang terletak pada tempat2 jang berbeda-beda pada diagram warna magnitudo daripada NGC 6383 telah dibahas sehubungan dengan idee Herbig mengenai tidak dilahirkannja bintang2 dalam sebuah gugus bintang pada saat bersamaan
Investigating star formation in the young open cluster NGC 6383
No full textContext: By studying young open clusters, the mechanisms important for star formation over several Myr can be examined. For example, accretion rate as a function of rotational velocity can be investigated. Similarly, sequential star formation triggered by massive stars with high mass-loss rates can be studied in detail. Aims: We identified and characterized probable members of NGC 6383, as well as determined cluster parameters. Methods: New Strömgren uvby CCD photometry, obtained by us, is presented. This new data, together with Johnson UBV and 2MASS data in the NIR, was used to investigate characteristics of pre- as well as zero age main sequence cluster members. Results: We present Strömgren uvby CCD photometry for 272 stars in the field of NGC 6383 and derive its reddening, E(b-y) = 0.21(4) mag, as well as distance, d = 1.7(3) kpc from the Sun. Several stars with NIR excess and objects in the domain of the classical Herbig Ae/Be and T Tauri stars were detected. Two previously known variables were identified as rapidly-rotating PMS stars. The field population is clearly separated from the probable members in the color-magnitude diagram. Conclusions: . NGC 6383 is a young open cluster, with an age of less than 4 Myr, undergoing continuous star formation. True pre-main sequence members might be found down to absolute magnitudes of +6 mag, with a variety of rotational velocities and stellar activities
[Republic Iron and Steel Co., Engine Drawing Card, Sketch No. 6383]
No full textThis engine drawing card was created for the Republic Iron + Steel Company, Class 8-38D. Section J-8D. Sketch 6383. Copy Spec. C-3368
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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