Galaxy evolution in nearby galaxy groups. III. A GALEX view of NGC 5846, the largest group in the local universe

We explore the co-evolution of galaxies in nearby groups (V < 3000 km/s) with a multi-wavelength approach. We analyze GALEX far-UV (FUV) and near-UV (NUV) imaging and SDSS u,g,r,i,z data of groups spanning a large range of dynamical phases. We characterize the photometric properties of spectroscopically-confirmed galaxy members and investigate the global properties of the groups through a dynamical analysis. Here we focus on NGC 5846, the third most massive association of Early-Type Galaxies (ETG) after the Virgo and Fornax clusters. The group, composed of 90 members, is dominated by ETGs (about 80 per cent), and among ETGs about 40\% are dwarfs. Results are compared with those obtained for three groups in the LeoII cloud, which are radically different both in member-galaxy population and dynamical properties. The FUV-NUV cumulative colour distribution and the normalized UV luminosity function (LF) significantly differ due to the different fraction of late-type galaxy population. The UV LF of NGC 5846 resembles that of the Virgo cluster, however our analysis suggests that star-formation episodes are still occurring in most of the group galaxies, including ETGs. The NUV-i colour distribution, the optical-UV colour-colour diagram, and NUV-r vs. Mr colour-magnitude relation suggest that the gas contribution cannot be neglected in the evolution of ETG-type group members. Our analysis highlights that NGC~5846 is still in an active phase of its evolution, notwithstanding the dominance of dwarf and bright ETGs and its virialized configuration.Comment: 26 pages, 13 figures, accepted for publication in MNRA

Cultural Memory and the Traumatic Past: Examining the Voids in Contemporary German and Uruguayan Literature, Museums, and Film

This thesis investigates how “voids” are used as a poetic lens in German and Uruguayan literature, film, music, museum spaces and memory places to excavate traumatic events of the twentieth-century and represent them in collective memory, further promoting a new understanding of historical experiences. These voids are used to symbolize gaping wounds left in Uruguayan culture after the military dictatorship of 1973-1985, the sense of absence and emptiness left in German-Jewish culture after the Holocaust and the breaks, ruptures and divisions in Germany post-WWII. Case studies include the architectural “Voids” in Libeskind’s Jewish Museum Berlin, “empty tombs” and installations on the “Disappeared” in the Museum of Memory in Montevideo and the powerful gaps, voids, wastelands and absences in literary texts by Peter Weiss, W.G. Sebald, Mauricio Rosencof, poetry by Mario Benedetti musicalized by Daniel Viglietti, and films by Wim Wenders, Richard Copan and Stan Neuman and Enrique Buchichio

ON THE SPECTRUM OF OCTAGON QUADRANGLE SYSTEMS OF ANY INDEX

An \emph{octagon quadrangle} is the graph consisting of a length $8$ cycle $(x_{1},x_{2},\dots,x_{8})$ and two chords, $\{x_{1},x_{4}\}$ and $\{x_{5},x_{8}\}$. An \emph{octagon quadrangle system} of order $v$ and index $\lambda$ is a pair $(X,\mathcal B)$, where $X$ is a finite set of $v$ vertices and $\mathcal B$ is a collection of octagon quadrangles (called blocks) which partition the edge set of $\lambda K_{v}$, with $X$ as vertex set. In this paper we determine completely the spectrum of octagon quadrangle systems for any index $\lambda$, with the only possible exception of $v=20$ for $\lambda=1$

Las relaciones con la prensa en el entorno digital. Nuevas prácticas y herramientas

The new paradigm in horizontal communication and dialogue with audiences, together with technological development and the spread of digital and multimedia tools, have not only had a big impact but also reformulated the management of communication Professionals and, as a result, in the areas of communication companies, organizations and institutions. These facts have deep implications in the profile of communication professionals and in the way in which they carry out specific managements that emerge from the area, such as the management of Media Relations and the Media.In recent years, there appeared some elements to take into account, since they determineand feature the new dynamics in which this management and link-up are developed, which are:immediacy, the synthesis of content which precedes all information delivery, the prevalence of image to text, new resources such as infographics, videos, links and connections between different social networks. Thus, new media formats are added to traditional messaging platforms which are intended to provide information of the company, organization or institution to journalists swiftly and according to the current environment. We are talking about new dynamics, logics, tools and platforms which do not replace the previous ones but are integrated in a distinct, unique and current mixture as befits a time in full deployment. Thus, in this context, let´s take into account certain considerations when circulating information to the press: 1) it is a time characterized by information surplus; 2) attention is divided over multiple screens and mobile devices; 3) the paradox likes inthe fact that consumption is rationed to everything which, in a few seconds is capable of catching attention and telling a story; 4) a story that can be possibly reduced to an image or to a high impact audiovisual format including additional material in other related digital formats, integrated into a multimedia platform, and 5) abilities and skills linked to digital design and new technologies such as aptitude to interpret and follow new trends in content on social network are required.Within this framework, communicators find a new challenge: learning to manage communication and transmit messages to the press with a new model that presents new variables in an ever-changing context. In this way, we are introduced to new elements that rethink the practices and the tools traditionally used in the management of Media Relations and the Media. The goal of the present research work was to revise, gather and introduce these new modes and options of tools to transmit informationto this key audience, because of the scope and visibility that it provides to the messages of the company or organization.El nuevo paradigma de la comunicación horizontal y del diálogo con las audiencias, junto con el desarrollo de la tecnología y la proliferación de herramientas digitales y multimedia, no solo han impactado sino también reformulado la gestión del profesional de la comunicación y, en consecuencia, de las áreas de comunicación de las empresas, organizaciones e instituciones. Esto tiene implicancias profundas en el perfil del profesional de comunicación y en el modo en que se llevan a cabo las gestiones específicas que se desprenden del área, como la gestión de las relaciones con la prensa y los medios de comunicación. En los últimos años surgieron elementos a tener en cuenta, que condicionan y delinean la nueva dinámica en que se desarrolla esta gestión y vinculación: la inmediatez, la síntesis de contenido que antecede toda entrega de información, la prevalencia de imágenes a textos, los nuevos recursos audiovisuales como infografías, videos, audios, enlaces y conexiones entre las distintas redes sociales. Así, se suman a las plataformas tradicionales de transmisión de mensajes nuevos formatos multimedia destinados a entregar la información de la empresa, organización o institución a los periodistas de manera ágil y acorde al entorno actual. Se trata de nuevas dinámicas, lógicas, herramientas y plataformas que no reemplazan a las anteriores sino que se integran en un mix nuevo, único y actual, que corresponde a esta época en pleno despliegue. Por esto, en este contexto, algunas consideraciones para tener en cuenta a la horade hacer circular información en la prensa: 1) es un tiempo caracterizado por la sobreabundancia de información; 2) la atención está repartida en múltiples pantallas y dispositivos móviles; 3) la paradoja es el consumo racionado, en aquello que logre en pocos segundos captar la atención y contar una historia; 4) una historia que pueda sintetizarse en lo posible en una imagen, o en un formato audiovisual de impacto, que incluya material complementario en otros formatos digitales relacionados, integrados en una plataforma multimedia; y 5) se requieren habilidades y destrezas vinculadas con el diseño digital y las nuevas tecnologías, como la capacidad de interpretar y seguir las nuevas tendencias en contenidos en redes sociales.En este marco, los comunicadores encuentran un nuevo desafío: aprender a gestionar la comunicación y transmitir los mensajes clave a la prensa, en un modelo nuevo que presenta nuevas variables, con un contexto en el que permanece el cambio constante. Así, se introducen nuevos elementos que reformulan las prácticas y las herramientas utilizadas tradicionalmente en la gestión de relaciones con la prensa y medios de comunicación. En este trabajo se revisaron, recopilaron y presentaron estas nuevas modalidades y opciones de herramientas para difundir información con este público clave, por el alcance y visibilidad que proporciona a los mensajes de la empresa u organización

Galaxy evolution in groups. NGC 3447/NGC 3447A: the odd couple in LGG 225

Local Group Analogs (LGA) are galaxy associations dominated by few bright Spirals, reminiscent of the LG. The NGC3447/NGC3447A system, member of the LGG 225 group, a nearby LGA, is considered a physical pair: an intermediate luminosity late type spiral, NGC3447, and an irregular companion, NGC3447A, linked by a faint filament of matter. A ring-like structure in the NGC3447 outskirts is emphasised by UV observations. This work aims to contribute to the understanding of galaxy evolution in low density environments, favourable habitat to highly effective encounters. We performed a multi-wavelength analysis of the surface photometry of this system to derive spectral energy distribution and structural properties using UV and optical images. We also characterised the velocity field of the pair using new kinematic observations. All these data are used to constrain smooth particle hydrodynamic simulations with chemo-photometric implementation to shed light on the evolution of this system. Luminosity profiles are all consistent with the presence of a disc extending and including NGC3447A. The overall velocity field does not emphasise any significant rotation pattern, rather a small velocity gradient between NGC3447 and NGC3447A. Our simulation, detached from a large grid explored to best-fit the global properties of the system, suggests that this arises from an encounter between two halos of equal mass. NGC3447 and NGC3447A belong to the same halo, NGC3447A being a substructure of the same disk as NGC3447. The halo gravitational instability, enhanced by the encounter, fuels a long lived instability in this dark matter dominated disk, driving its morphology. This system may warn about a new class of "false pairs" and the potential danger of a misunderstanding of such objects in pair surveys that could produce a severe underestimate of the total mass of the system. (abridged)Comment: 14 pages, 10 figures, A&A accepte

The UV window on counter rotating ETGs: insight from SPH simulations with chemo-photometric implementation

The Galaxy Evolution Explorer (GALEX) detected ultraviolet emission in about 50% of multi-spin early-type galaxies (ETGs), suggesting the occurrence of a recent rejuvenation episode connected to the formation of these kinematical features. With the aim at investigating the complex evolutionary scenario leading to the formation of counter rotating ETGs (CR-ETGs) we use our Smooth Particle Hydrodynamic (SPH) code with chemo-photometric implementation. We discuss here the UV evolutionary path of two CR-ETGs, NGC 3593 and NGC 5173, concurrently best fitting their global observed properties, i.e., morphology, dynamics, as well as their total B-band absolute magnitude and spectral energy distribution (SED) extended over three orders of magnitude in wavelength. These simulations correspond to our predictions about the target evolution which we follow in the color-magnitude diagram (CMD), near-UV (NUV) versus r-band absolute magnitude, as a powerful diagnostic tool to emphasize rejuvenation episodes.Comment: 7 pages, 3 figures, accepted for publication in ApS