2,291 research outputs found
Tidal disruptions in circumbinary disks. II: Observational signatures in the reverberation spectra
Supermassive Binary Black Holes (SMBBHs) with sub-pc separations form in the
course of galaxy mergers, if both galaxies harbour massive black holes. Clear
observational evidence for them however still eludes us. We propose a novel
method of identifying these systems by means of reverberation mapping their
circumbinary disk after a tidal disruption event has ionized it. The tidal
disruption of a star at the secondary leads to strong asymmetries in the disk
response. We model the shape of the velocity--delay maps for various toy disk
models and more realistic gas distributions obtained by SPH simulations. The
emissivity of the ionized disk is calculated with {\em Cloudy}. We find
peculiar asymmetries in the maps for off center ionizing sources that may help
us constrain geometrical parameters of a circumbinary disk such as semi-major
axis and orbital phase of the secondary, as well as help strengthen the
observational evidence for sub-parsec SMBBHs as such.Comment: 10 pages, 5 figures. Accepted for publication in Ap
O papel das populações tradicionais na conservação da biodiversidade.
bitstream/CNPF-2009-09/42622/1/Doc153.pdf1 CD-ROM
Transient chaos under coordinate transformations in relativistic systems
We use the H\'enon-Heiles system as a paradigmatic model for chaotic
scattering to study the Lorentz factor effects on its transient chaotic
dynamics. In particular, we focus on how time dilation occurs within the
scattering region by measuring the time in a clock attached to the particle. We
observe that the several events of time dilation that the particle undergoes
exhibit sensitivity to initial conditions. However, the structure of the
singularities appearing in the escape time function remains invariant under
coordinate transformations. This occurs because the singularities are closely
related to the chaotic saddle. We then demonstrate using a Cantor-like set
approach that the fractal dimension of the escape time function is relativistic
invariant. In order to verify this result, we compute by means of the
uncertainty dimension algorithm the fractal dimensions of the escape time
functions as measured with inertial and comoving with the particle frames. We
conclude that, from a mathematical point of view, chaotic transient phenomena
are equally predictable in any reference frame and that transient chaos is
coordinate invariant
Estudos fitossociológicos em agroflorestas e regeneração natural na floresta atlântica densa.
Editores técnicos: Marcílio José Thomazini, Elenice Fritzsons, Patrícia Raquel Silva, Guilherme Schnell e Schuhli, Denise Jeton Cardoso, Luziane Franciscon. EVINCI. Resumos
Recuperação de áreas degradadas como instrumento para a conservação das florestas nativas.
Palestra
Mutirões de trabalho em agroflorestas agroecológicas: variações e padrões nas atividades e práticas.
Sistematização de técnicas de plantio e manejo de agroflorestas.
Editores técnicos: Marcílio José Thomazini, Elenice Fritzsons, Patrícia Raquel Silva, Guilherme Schnell e Schuhli, Denise Jeton Cardoso, Luziane Franciscon. EVINCI. Resumos
Research Update on Extreme-Mass-Ratio Inspirals
The inspirals of stellar-mass mass compact objects into massive black holes
in the centres of galaxies are one of the most important sources of
gravitational radiation for space-based detectors like LISA or eLISA. These
extreme-mass-ratio inspirals (EMRIs) will enable an ambitious research program
with implications for astrophysics, cosmology, and fundamental physics. This
article is a summary of the talks delivered at the plenary session on EMRIs at
the 10th International LISA Symposium. It contains research updates on the
following topics: astrophysics of EMRIs; EMRI science potential; and EMRI
modeling.Comment: 17 pages, no figures. Proceedings of the LISA Symposium X, to be
published at the Journal of Physic
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