Avante Hermética : produção de plano de comunicação para estimular a integração e motivar a participação de discentes na atlética

Trabalho de conclusão de curso (graduação)—Universidade de Brasília, Faculdade de Comunicação, Departamento de Comunicação Organizacional, 2018.Este trabalho tem como objetivo propor um plano de comunicação para a atlética da Faculdade de Comunicação da UnB, a Hermética. O objetivo é produzir um plano de comunicação para estimular a integração e motivar a participação dos discentes na atlética. Tendo como base teórica os principais conceitos de motivação, associação atlética acadêmica e instrumentos de Comunicação, foi elaborado um questionário e um roteiro de entrevista para investigar o cenário em que a Hermética está inserida. Com base nas informações coletadas foi elaborada uma análise dos resultados e, posteriormente, foram estabelecidos objetivos, estratégias e ações de comunicação para que a associação alcance seus objetivos e sua visão

A Fallback Disk Model for Ultraluminous X-ray Sources

Current stellar evolution models predict that during the core collapse of massive stars, a considerable amount of the stellar material will fall back onto the compact, collapsed remnants (neutron stars or black holes), usually in the form of an accretion disk. This triggers rapid mass accretion onto, e.g., the black hole, and produces energetic explosions known as Gamma-ray bursts. However it is very difficult to prove the existence of an accretion disk around newborn black holes observationally. Here we demonstrate that some of the ultraluminous X-ray sources in nearby galaxies, which are associated with supernova remnants, may be black holes accreting from their fallback disks, i.e., they have evolved from collapsars. Since it is almost certain that there is an accretion disk around these black holes, this would for the first time lend the observational support to the collapsar model.Comment: 6 pages, accepted for publication in ApJ

Iron K-alpha Fluorescent Line Profiles from Spiral Accretion Flows in AGNs

We present 6.4 keV iron K-alpha fluorescent line profiles predicted for a relativistic black hole accretion disk in the presence of a spiral motion in Kerr geometry, the work extended from an earlier literature motivated by recent magnetohydrodynamic (MHD) simulations. The velocity field of the spiral motion, superposed on the background Keplerian flow, results in a complicated redshift distribution in the accretion disk. An X-ray source attributed to a localized flaring region on the black hole symmetry axis illuminates the iron in the disk. The emissivity form becomes very steep because of the light bending effect from the primary X-ray source to the disk. The predicted line profile is calculated for various spiral waves, and we found, regardless of the source height, that: (i) a multiple-peak along with a classical double-peak structure generally appears, (ii) such a multiple-peak can be categorized into two types, sharp sub-peaks and periodic spiky peaks, (iii) a tightly-packed spiral wave tends to produce more spiky multiple peaks, whereas (iv) a spiral wave with a larger amplitude seems to generate more sharp sub-peaks, (v) the effect seems to be less significant when the spiral wave is centrally concentrated, (vi) the line shape may show a drastic change (forming a double-peak, triple-peak or multiple-peak feature) as the spiral wave rotates with the disk. Our results emphasize that around a rapidly-rotating black hole an extremely redshifted iron line profile with a noticeable spike-like feature can be realized in the presence of the spiral wave. Future X-ray observations, from {\it Astro-E2} for example, will have sufficient spectral resolution for testing our spiral wave model which exhibits unique spike-like features.Comment: 30 pages, 10 figures, submitted to ApJ, will be presented at 204th Meeting of AAS in Denve

Long-term multi-wavelength studies of GRS 1915+105 I. A high-energy and mid-infrared focus with RXTE, INTEGRAL, and Spitzer

To date, mid-infrared properties of Galactic black hole binaries have barely been investigated in the framework of multi-wavelength campaigns. Yet, studies in this spectral domain are crucial to get complementary information on the presence of dust and/or on the physical processes such as dust heating and thermal bremsstrahlung. Here, we report a long-term multi-wavelength study of the microquasar GRS 1915+105. On the one hand, we aimed at understanding the origins of the mid-infrared emission, and on the other hand, at searching for correlation with the high-energy and/or radio activities. We observed the source at several epochs between 2004 and 2006 with the photometer IRAC and spectrometer IRS, both mounted on the Spitzer Space Telescope. When available, we completed our set of data with quasi-simultaneous RXTE and INTEGRAL high-energy and/or Ryle radio observations from public archives. We then studied the mid-infrared environment and activities of GRS 1915+105 through spectral analysis and broad band fitting of its radio to X-ray spectral energy distributions. We detected polycyclic aromatic hydrocarbon molecules in all but one IRS spectra of GRS 1915+105 which unambiguously proves the presence of a dust component, likely photoionised by the high-energy emission. We also argue that this dust is distributed in a disc-like structure heated by the companion star, as observed in some Herbig Ae/Be and isolated cool giant stars. Moreover, we show that some of the soft X-ray emission emanating from the inner regions of the accretion disc is reprocessed and thermalised in the outer part. This leads to a mid-infrared excess that is very likely correlated to the soft X-ray emission. We exclude thermal bremsstrahlung as contributing significantly in this spectral domain.Comment: 46 pages, 6 tables, 6 figures, accepted in Ap

Spectral Components of SS 433

We present results from new optical and UV spectroscopy of the unusual binary system SS 433, and we discuss the relationship of the particular spectral components we observe to the properties of the binary. (1) The continuum spectrum which we associate with flux from the super-Eddington accretion disk and the dense part of its wind. (2) H-alpha moving components which are formed far from the binary orbital plane in the relativistic jets. (3) H-alpha and He I "stationary" emission lines which we suggest are formed in the disk wind in a volume larger than the dimensions of the binary. (4) A weak "stationary" emission feature we identify as a C II 7231,7236 blend that attains maximum radial velocity at the orbital quadrature of disk recession. (5) Absorption and emission features from outflowing clumps in the disk wind (seen most clearly in an episode of blue-shifted Na I emission). (6) We found no clear evidence of the absorption line spectrum of the optical star, although we point out the presence of He I absorption features (blended with the stationary emission) with the expected radial velocity trend at the orbital and precessional phases when the star might best be seen. (7) A rich interstellar absorption spectrum of diffuse interstellar bands. The results suggest that the binary is embedded in an expanding thick disk (detected in recent radio observations) which is fed by the wind from the super-Eddington accretion disk.Comment: Submitted to Ap