1,720,988 research outputs found
Hidden features of AGN revealed by PIPS. First results of the morphological survey
No full textThe new CCD imaging program of the representative sample of Seyfert galaxies is shortly described. Various morphological details, revealed in broad band colour images, in H_alpha -emission images and in Laplace-filtered images, are discussed for two galaxies in this sample
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Analysis of the interaction effects in the southern galaxy pair Tol 1238-364 and ESO 381-G009
No full textIn the context of the connection among galaxy-galaxy interaction, starbursts, and nuclear activity, we present and discuss a quantitative morphological analysis based on BVR images and a detailed spectroscopic investigation of two interacting galaxies, the Seyfert 2 Tol 1238-364 (IC 3639) and its companion ESO 381-G009, forming a triple system with ESO 381-G006. Broadband optical photometry is complemented by Hα imaging, which provides information about the distribution of star-forming regions across the galaxies. Long-slit spectroscopic data obtained at different position angles of the slit are employed to determine the physical conditions of circumnuclear and extranuclear regions. A mixture of thermal and nonthermal ionizing radiation is found in the surroundings of the nucleus of Tol 1238-364, and the energy budget supports the presence of a circumnuclear starburst. Several regions in both the galaxies show anomalous line ratios: additional ionization by shock heating and low ionization of some extranuclear H II regions are suggested as possible explanations. An analysis of the emission-line profiles reveals the presence of a broad Hα component in the nuclear region of Tol 1238-364. Independent estimates of the star formation rates (SFRs) were obtained through flux-calibrated Hα images and far-infrared (FIR) emission in the four IRAS bands. Overall, SFR densities have been compared with the SFR densities derived from Hα emission in the individual regions of the galaxies sampled by long-slit spectra. In both the galaxies an enhancement of the star formation activity with respect to isolated galaxies is revealed. The prevalence of starburst or nuclear activity has been examined through FIR color indices. The interaction scenario is discussed on the basis of the observed galaxy properties
The Seyfert II galaxy Tol1238-364 and its companion ESO381-G009: long slit spectroscopy and IRAS data analysis
No full textThe results of a spectroscopic study of the pair of galaxies Tol 1238-364 and ESO 381-G009 are presented. Long-slit spectroscopy at different slit position angles combined with Laplace filtering of Hα images of the two galaxies allowed to isolate several circumnuclear and extranuclear regions. Physical properties have been derived by means of a grid of photoionization models computed with the code Cloudy 90. Star formation rates in both galaxies have been calculated and compared with their infrared emission, obtained from IRAS data after application of the Maximum Entropy method
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