RESUMEN Este trabajo estudia la conexión entre las primeras galaxias y sus halos de materia oscura en el Universo temprano, cuando la reionización está concluyendo. Nuestros modelos teóricos (presentados en un trabajo previo) trazan la historia de formación estelar en z = 4 - 8, la función de masa estelar, la distribución de masa estelar a masa de halo, y otras estadísticas de las galaxias a alto corrimiento al rojo. Todas estas predicciones concuerdan con las observaciones actuales y con otras simulaciones numéricas de alta resolución. Un hallazgo crucial de este trabajo es la sólida estimación de la historia cósmica de formación estelar (a través de la implementación de vientos galácticos y de supernovas y procesos de enfriamiento atómico y molecular), y un esquema autoconsistente para el enriquecimiento químico en el medio intergaláctico. Además, los modelos teóricos son compatibles con una pendiente en el límite débil de la función de luminosidad de las galaxias con α = -2 al final de la reionización.

ABSTRACT This work studies the connection between the first galaxies and their hosting dark matter halos in the early Universe when reionization is concluding. Our numerical models (already presented in an earlier study) trace the star formation history at z = 4 - 8, the galaxy stellar mass function, the stellar-to-halo mass distribution, and other high redshift galaxies statistics. All these predictions are consistent with observations to date and with other high-resolution cosmological simulations. A key finding of this work is the robust estimate of the cosmic star formation history (through the implementation of galaxy and supernova winds and atomic and molecular cooling processes) and self-consistent chemical pollution of the intergalactic medium. The theoretical models are compatible with a faint-end slope of the galaxy luminosity function of α = -2 at the end of reionization.

Abstract In the paper a scenario of an electromagnetic response formation from the merging of two black holes is considered. In this scenario it’s assumed that the binary black hole is surrounded by an accretion disk. As a result of the black holes merging and mass loss, the accretion disk experiences a disturbance, which is accompanied by shock waves propagation of sufficiently high intensity. Heating of matter by shock waves leads to a sharp increase in the flux of electromagnetic radiation from the disk. The paper includes a calculated light curve, radiation spectrum, and the estimation of characteristic duration of the flare. This method can be used to discover of electromagnetic responses from gravitational-wave events, which registered by the LIGO (Laser Interferometer Gravitational-Wave Observatory) and the Virgo detectors. Supporting the registration of gravitational-wave events by observations in the electromagnetic channel has far-reaching prospects, since it corresponds to the multi-messenger approach to the study of astrophysical objects.

As novas diretrizes da Base Nacional Comum Curricular sugere Unidades Temáticas onde os temas de Estrutura e Evolução das Estrelas têm um lugar natural. Porém, um levantamento recente mostrou que o tema da Formação das Estrelas quase nem é abordado na literatura. Apresentamos neste trabalho um panorama completo deste assunto com a intenção de fornecer subsídios para seu tratamento em sala de aula, atualizado e acessível aos professores da Ciências.

The new directions of the National Common Curricular Standards suggest Thematic Units in which the Structure and Evolution of Stars have a natural plane. However, a recent survey showed that the Formation of Stars is almost not addressed in the literature. We present in this work a complete panoramic view of this subject with the intention of providing a base for its presentation in the classroom, updated and accessible to Science teachers.

ABSTRACT In search for a connection between the formation of stars and the formation of planets, a new semi-automatic spectral analysis method using iSpec was developed for the TIGRE telescope installed in Guanajuato, Mexico. TIGRE is a 1.2m robotic telescope, equipped with an Echelle spectrograph (HEROS), with a resolution R ⋍ 20000. iSpec is a synthetic spectral fitting program for stars that allows to determine in an homogeneous way their fundamental parameters: effective temperature, Teff , surface gravity, log g, metallicities, [M=H] and [Fe=H], and rotational velocity, V sin i. In this first article we test our method by analysing the spectra of 46 stars, hosts of exoplanets, obtained with the TIGRE.

RESUMEN En la búsqueda de una conexión entre la formación estelar y planetaria, se desarrolló un nuevo método semiautomático de análisis espectral estelar usando iSpec, para el telescopio TIGRE, instalado en Guanajuato, México. El TIGRE es un telescopio robótico de 1.2m, el cual está equipado con el espectrógrafo Echelle HEROS, que tiene una resolución R ≃ 20; 000. iSpec es un programa de ajuste espectral sintético para estrellas que permite determinar de manera homogénea sus parámetros fundamentales: temperatura efectiva, Teff, gravedad superficial, log g, metalicidades, [M=H] y [Fe=H], y velocidad de rotación, V sin i. En este artículo, probamos nuestro método, analizando una muestra de 46 estrellas que albergan exoplanetas observadas por el TIGRE.

ABSTRACT A sample of 46 stars, host of exoplanets, is used to search for a connection between their formation process and the formation of the planets rotating around them. Separating our sample into two, stars hosting high-mass exoplanets (HMEs) and low-mass exoplanets (LMEs), we found the former to be more massive and to rotate faster than the latter. We also found the HMEs to have higher orbital angular momentum than the LMEs and to have lost more angular momentum through migration. These results are consistent with the view that the more massive the star and the higher its rotation, the more massive was its protoplanetarys disk and rotation, and the more efficient was the extraction of angular momentum from the planets.

RESUMEN Una muestra de 46 estrellas que albergan exoplanetas se usa para la búsqueda de una conexión entre su proceso de formación y el proceso de formación de los planetas que las orbitan. Separamos nuestra muestra en dos: estrellas que albergan exoplanetas de baja masa (LME) y de alta masa (HME); encontramos que las estrellas con HMEs rotan preferentemente alrededor de estrellas con alta masa y con mayor rotación que las estrellas con LMEs. También encontramos que las HMEs tienen un momento angular orbital más alto que las LMEs y que perdieron más momento angular durante su migración. Nuestros resultados son congruentes con un modelo en el cual las estrellas más masivas con alta rotación forman discos protoplanetarios más masivos que también rotan mas rápido, y que además son más eficientes en disipar el momento angular de sus planetas.

ABSTRACT This work is devoted to the study of the star formation histories (SFHs) of the brightest cluster galaxies (BCGs) with intermediate central ages (from 5 to 10Gyr), to confirm if BCGs with these ages represent different accretion histories or simply a stochastic effect. The sample is composed of 6 BCGs with intermediate central ages and 3 BCGs with old central ages (> 12Gyr) as comparison galaxies. The galaxies were observed with the integrated field spectrograph VIMOS installed in the Very Large Telescope (VLT). The SFHs were obtained with the full spectrum fitting technique using the star population code STARLIGHT. The BCGs of intermediate central age analyzed formed almost 100% of their stars at z > 2 and their SFHs are similar to the SFHs of BCGs of old central ages and elliptical galaxies of similar mass (MDyn > 10 11 M ⊙); therefore, these BCGs do not represent different SFHs.

RESUMEN Este trabajo está dedicado al estudio de las historias de formación estelar (HFE) de BCGs (brightest cluster galaxies) con edades centrales intermedias (de 5 a 10Ga), para confirmar si BCGs con estas edades representan historias de acreción distintas o si es simplemente un efecto estocástico. La muestra está compuesta de 6 BCGs con edades intermedias y 3 BCGs con edades centrales viejas (> 12Ga) como galaxias de comparación. Las galaxias se observaron con el espectrógrafo de campo integrado VIMOS instalado en el VLT (Very Large Telescope). Las HFE se obtuvieron con la técnica de ajuste de todo el espectro usando el código de poblaciones estelares STARLIGHT. Las BCGs de edades centrales intermedias analizadas formaron casi el 100% de sus estrellas a z > 2 y sus HFE son similares a las HFE de BCGs de edades centrales viejas y de galaxias elípticas de masa similar (MDin > 10 11 M ⊙); por tanto, estas BCGs no representan HFE distintas.

Abstract We discuss in this work the issue of chemical element origin in the stars and the Big Bang, with the aim of linking the subject smoothly with the formation of the Solar System and the structure of the Earth in an updated and pedagogical fashion. A few cases in which these subjects are present but disjoint in different degrees are shown, and a suggestion for its introduction in a set of classes made, as well as issues in Teacher's Education and existing Curricula revisited. The goal is to break the boundaries of separated presentation and to emphasize the unity and coherence of sciences.

ABSTRACT This paper aims to discuss the archival institutions context and the role of archival professionals in the present day. It demonstrates how the information paradigm has reshaped the archivists activities, as well as uses and users of the archival record. To do so, a parallel as traced with Inside Out (2015), a movie about Riley, an 11-year-old girl who lives in conflict with herself and her parents after moving from her hometown. The stars are five emotions: Joy, Sadness, Fear, Disgust, and Anger, responsible for the girl's personality characteristics and also for the storage and treatment of her memories. In this context, it is possible to perceive through the film the idea of the mind as an archival institution, and of the emotions as archival professionals responsible for accumulating, selecting, storing and discarding the character's memories. In the movie reality, Riley's memories are records of great importance in the constitution of the character's identity and in her interaction with her social groups. Thus, we can say that archival institutions are organic environments, in transformation and strongly marked by the work of archivists, seen as agents of memory that are fundamental to the formation of identities. This representation goes against some of the main characteristics consolidated in the area, such as the naturalness of documents and the impartiality of archival professionals. Finally, it also redefines the archival record, which is now understood from the point of view of information. day activities record so 2015, 2015 , (2015) Riley 11yearold yearold 11 year old hometown Joy Sadness Fear Disgust Anger girls s institution accumulating selecting characters character reality Rileys groups Thus environments identities area Finally 201 (2015 1 20 (201 2 (20 (2 (

RESUMO Objetiva discutir o contexto das instituições arquivísticas e o papel dos profissionais de arquivo na atualidade. Demonstrar como o paradigma da informação tem redimensionado não apenas as atividades dos arquivistas, mas também os usos e usuários do documento arquivístico. Para tanto, buscamos traçar um paralelo com o filme Divertida Mente (2015) que conta a história de Riley, uma menina de 11 anos, que vive em conflito, consigo e com seus pais, após se mudar de sua cidade natal. O filme é protagonizado pelas emoções, Alegria, Tristeza, Medo, Nojinho e Raiva, responsáveis por conferir à menina suas características de comportamento e também pelo armazenamento e tratamento de suas memórias. Nesse sentido, é possível apreender através do filme a ideia da mente como uma instituição arquivística, e das emoções como profissionais de arquivo responsáveis pela acumulação, seleção, armazenamento e descarte das memórias da personagem. Temos nessa realidade imaginada através do filme, as memórias de Riley como documentos arquivísticos fundamentais na constituição da identidade da personagem e na sua interação com os grupos sociais dos quais faz parte. Assim, podemos dizer que as instituições arquivísticas são ambientes orgânicos, em transformação e fortemente marcados pela atuação dos arquivistas, vistos como agentes de memória fundamentais na formação das identidades. Essa representação vai de encontro a algumas das principais características cristalizadas na área, como a naturalidade dos documentos e a imparcialidade dos profissionais de arquivo. Por fim, também redimensiona o documento arquivístico que passa a ter seu horizonte traçado pela noção de informação. atualidade arquivistas tanto 2015 (2015 1 anos conflito pais natal Alegria Tristeza Medo Raiva sentido arquivística acumulação seleção parte Assim orgânicos identidades área fim 201 (201 20 (20 2 (2 (

Resumo Um século depois de observada a deflexão da luz emitida pelas estrelas distantes, durante o eclipse solar de 1919, é interessante saber os conceitos que emergiram do experimento e suas consequências teóricas e observacionais para a cosmologia e astrofísica moderna. Além de confirmar a teoria gravitacional de Einstein, o maior legado foi a construção de uma nova área de pesquisa na ciência do cosmos, conhecida como lentes gravitacionais. A formação e magnificação de imagens múltiplas (miragens) pelo campo gravitacional de uma lente compacta ou extensa, estão entre os mais impressionantes fenômenos da natureza. Neste artigo apresentamos uma visão pedagógica do primeiro efeito genuíno de lente gravitacional, o quasar duplo QSO 0957+561. Descrevemos a formação de anéis, dos arcos gigantes, pequenos arcos e imagens múltiplas de Supernovas. é também surpreendente que a constante de Hubble e a quantidade de matéria escura no Universo possam ser mensuradas pela mesma técnica. Finalmente, o lenteamento de ondas gravitacionais, um efeito possível mas ainda não detectado, será também brevemente discutido.

Abstract A century after observing the deflection of light emitted by distant stars during the solar eclipse of 1919, it is interesting to know the concepts emerged from the experiment and the theoretical and observational consequences for modern astrophysics and cosmology. In addition to confirming Einstein's gravitational theory, its greatest legacy was the construction of a new research area to cosmos science dubbed gravitational lensing. The formation and magnification of multiple images (mirages) by the gravitational field of a compact or extended lens are among the most striking phenomena of nature. This article presents a pedagogical view of the first genuine gravitational lens effect, the double quasar QSO 0957 + 561. We also describe the formation of rings, giant arcs, arclets and multiple Supernova images. It is also surprising that the Hubble constant and the amount of dark matter in the Universe might be estimated by the same technique. Finally, the lensing of gravitational waves, a possible but still not yet detected effect, is also briefly discussed.

Abstract In this work we estimate the star formation rate (SFR) through 333 LongGRBs detected by Swift. This investigation is based on the empirical model proposed by Yüksel et al. (2008). Basically, the SFR is estimated using long-GRBs considering that they have a stellar origin based on the collapsar model or the collapse of massive stars (hypernovae) M > 20M⊙. The analysis starts with the study of ε(z) which accounts for the long-GRBs production rate and is parameterized by ε(z) = ε0(1 + z)δ, where ε0 includes the SFR absolute conversion to GRBs rate in a luminosity range already defined and δ is a dynamical parameter which changes at different regions of redshift; it accounts for the SFR slope which is obtained by an analysis of linear regression over our long-GRBs sample. The results obtained provide evidence that supports our proposal to use Long-GRBs as tracers of SFR.

Resumen En este trabajo se estima la tasa de formación estelar (SFR) mediante el análisis de una muestra de 333 Gamma Ray Bursts (GRBs) largos detectados por Swift. Este estudio se basa en el modelo empírico propuesto por Yüksel et al. (2008). Básicamente, la SFR se calcula utilizando GRBs largos tomando en consideración que son originados según el modelo collapsar o del colapso de estrellas masivas tipo hipernova (M > 20M⊙). El análisis parte del estudio de ε(z) que representa la tasa de producción de GRBs largos, parametrizándolo de la forma ε(z) = ε0(1+z)δ, donde ε0 incluye la conversión absoluta de la SFR a la tasa de GRB en un intervalo de luminosidad de GRB dado, y el índice δ es un parámetro dinámico que cambia con z y representa la pendiente de la traza dejada por la SFR. Los resultados favorecen la propuesta usar a los GRBs largos como trazadores de la SFR.

ABSTRACT An ubiquitous feature of stellar systems, particularly of transitional disks, is their variability across the full range of the electromagnetic spectrum. The contribution to the near-infrared region of the spectrum comes mainly from the inner region of the disk, where gas and dust are heated to extremely high temperatures. We present a new physical mechanism that can explain the near-infrared variability of some transitional disks. The main process is the intermittent formation of a sublimation wall due to an instability between the magnetic field of the star and the innermost disk region. When the wall is present, it contributes to the spectrum but also shadows part of the material beyond its location. Using this mechanism, we present a model to explain the near-infrared variability of the transitional disk around GM Aur.

RESUMEN Una característica común a los sistemas estelares, particularmente a los discos transicionales, es su variabilidad en el intervalo completo del espectro electromagnético. La contribución a la región del cercano infrarrojo del espectro proviene principalmente de la región interna del disco, donde el gas y el polvo se calientan hasta alcanzar temperaturas muy altas. Proponemos un nuevo mecanismo capaz de explicar la variabilidad en el cercano infrarrojo de algunos discos transicionales. El proceso principal es la formación intermitente de una pared de sublimación debida a una inestabilidad entre el campo magnético de la estrella y la región más interna del disco; cuando la pared esta´ presente, contribuye al espectro pero también oculta parte del material más allá de este punto. Usando este mecanismo, presentamos un modelo para explicar la variabilidad en el cercano infrarrojo del disco transicional alrededor de GM Aur.

ABSTRACT We consider 28 particle-based simulations aimed at comparing the gravitational collapse of a spherically symmetric, uniform gas core in which two extreme types of turbulent spectra of velocity have been initially induced, so that ∇ ν → = 0 (14 simulations) and ∇× ν → = 0 (14 simulations). For all the simulations, the ratios of the kinetic energy and thermal energy to the gravitational energy were fixed at β=0.21 and α=0.24, respectively. Most of the simulations finish by forming a single protostar, except for two simulations that form a binary system of protostars. In order to quantify the differences (or similarities) between the two types of simulations, we calculate some integral properties of the resulting protostars, such as the mass Mf and the ratios αf and βf.

RESUMEN Consideramos 28 simulaciones de partículas diseñadas para comparar el colapso gravitacional de un núcleo de gas uniforme y esféricamente simétrico, en el cual dos tipos extremos de espectros turbulentos de velocidad han sido inicialmente inducidos, de modo que ∇· ν → = 0 (14 simulaciones) y ∇× ν → = 0 (14 simulaciones). En todas las simulaciones las razones de energía cinética y energía térmica con respecto a la energía gravitacional se han fijado en β=0.21 y α=0.24, respectivamente. La mayoría de las simulaciones terminan formando una sola protoestrella, excepto dos simulaciones, en las se forma un sistema binario de protoestrellas. Con el propósito de cuantificar las diferencias (o similitudes) entre los dos tipos de simulaciones, calculamos algunas propiedades integrales de las protoestrellas resultantes, tales como la masa Mf y las razones αf and βf.

ABSTRACT It is a well known result that a periodic ejection variability in a hypersonic jet results in the production of a train of internal working surfaces (one working surface produced by each period of the ejection variability) travelling down the jet beam. This mechanism has been successfully applied to model the knot structures of Herbig-Haro (HH) jets. In this paper we explore the possibility of producing more than one working surface with each ejection variability period. We derive the mathematical criteria that have to be satisfied by the functional form of an ejection velocity variability that produces double working surfaces, and study a family of functions with appropriate properties.

RESUMEN Es un resultado conocido que una expulsión variable periódica en un chorro hipersónico tiene como resultado la producción de una cadena de superficies de trabajo internas (una superficie de trabajo por cada período de la variabilidad) que viajan a lo largo del chorro. Este mecanismo ha sido exitosamente aplicado para modelar las estructuras de nudos de chorros Herbig-Haro (HH). En el presente artículo exploramos la posibilidad de producir más de una superficie de trabajo con cada período de la expulsión variable. Derivamos criterios matemáticos que deben ser satisfechos por la forma funcional de una velocidad de expulsión variable que produzca superficies de trabajo dobles, y estudiamos una familia de funciones con propiedades apropiadas.

Abstract We present an analysis of the IRAS 08589−4714 star-forming region. This region harbors candidate young stellar objects identified in the WISE and Herschel images using color index criteria and spectral energy distributions (SEDs). The SEDs of some of the infrared sources and the 70 μm radial intensity profile of the brightest source are modeled using the DUSTY code. For these objects, we estimate the main parameters, which suggest that they are very young, massive and luminous objects at early stages of the formation process. We use the emission distribution in the infrared at 70 and 160 μm to estimate the dust temperature gradient. This suggests that the nearby massive starforming region RCW 38, located at ≈10pc from the IRAS source position, may be contributing to the photodissociation of the molecular gas and to the heating of the interstellar dust in the environs of the IRAS source.

Resumen Se presenta un análisis de la región de formación de estrellas masivas IRAS 08589−4714. Esta región alberga candidatos a objetos estelares jóvenes, los cuales fueron identificados en las imágenes de WISE y Herschel empleando criterios basados en índices de color y distribuciones espectrales de energía (SEDs). Las SEDs de algunas de las fuentes y el perfil radial de intensidad en 70 μm de la fuente más brillante se modelan mediante el código DUSTY. Para estos objetos, se estimaron los principales parámetros físicos, los cuales indican que se trata de objetos muy jóvenes y masivos en las primeras etapas del proceso de formación. Se emplea la distribución de la emisión en el infrarrojo en 70 y 160 μm para estimar el gradiente de temperatura del polvo. Esto indica que la región de formación estelar RCW 38 (a ≈10 pc de la fuente IRAS), podría contribuir a la foto-disociación del gas molecular y al calentamiento del polvo interestelar en las inmediaciones de la fuente IRAS.

Resumen Se examinaron los cambios histológicos y morfológicos producidos en la punta del brazo de la ofiura Ophioplocus januarii luego de su amputación. En el presente trabajo se describe el proceso de cicatrización de la herida y se lo compara con otras especies de la misma Clase. Este proceso en O. januarii involucra el cierre de la herida, la reparación del tejido dañado y la posterior formación de un presunto blastema formado por células indiferenciadas, esclerocitos y presuntas células blastémicas. Los esclerocitos son las células más abundantes debido a que estas células son cruciales para la regeneración del esqueleto. Los resultados encontrados en este estudio apoyan los resultados que se encuentran en otras estrellas frágiles.

Abstract Wound healing in the arm tip after amputation in the brittle star Ophioplocus januarii was examined in San José gulf, Argentina, to observe histological and morphological changes. The process of wound healing is described and compared with other brittle stars species. This process in O. januarii involves the closure of the wound, the repair of the tissue damage and posterior formation of a presumptive stalked blastema by undifferentiated cells, sclerocytes and presumptive blastemic cells. The sclerocytes are the most abundant cell type due to this cells are crucial to the future skeleton regeneration. The results found in this study support the results found in others brittle stars Rev. Biol. Trop. 63 (Suppl. 2): 297-308. Epub 2015 June 01.