A. H. Cerqueira

Universidade Estadual de Santa Cruz

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

E. M. de Gouveia Dal Pino

Universidade de São Paulo

M. J. Vasconcelos

Universidade Estadual de Santa Cruz

A. C. Raga

Universidad Nacional Autónoma de México

Mayana Zatz

Universidade de São Paulo

P. F. Velázquez

Universidad Nacional Autónoma de México

Fabio De Colle

Universidad Nacional Autónoma de México

A. Esquivel

Universidad Nacional Autónoma de México

Mariz Vainzof

Universidade de São Paulo

Ronaldo Lima Gomes

Universidade Estadual de Santa Cruz

Maria Rita Passos‐Bueno

Universidade de São Paulo

Cooperative Institutions

Universidade de São Paulo

Universidad Nacional Autónoma de México

Centre National de la Recherche Scientifique

Instituto Nacional de Investigaciones Nucleares

Universidade Estadual de Santa Cruz

National Institute for Space Research

Instituto Biológico

Universidade Federal de São Paulo

Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo

Instituto de Geofísica y Astronomía

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Emission lines from rotating proto-stellar jets with variable velocity profiles

Astronomy and Astrophysics (2006)

A. H. Cerqueira P. F. Velázquez A. C. Raga M. J. Vasconcelos Fabio De Colle

Using the Yguazú-a three-dimensional hydrodynamic code, we have computed a set of numerical simulations of heavy, supersonic, radiatively cooling jets including variabilities in both the ejection direction (precession) and the jet velocity (intermittence). In order to investigate the effects of jet rotation on the shape of the line profiles, we also introduce an initial toroidal rotation velocity profile, in agreement with some recent observational evidence found in jets from T Tauri stars which seems to support the presence of a rotation velocity pattern inside the jet beam, near the jet production region. Since the Yguazú-a code includes an atomic/ionic network, we are able to compute the emission coefficients for several emission lines, and we generate line profiles for the Hα, [O I]λ6300, [S II]λ6716 and [N II]λ6548 lines. Using initial parameters that are suitable for the DG Tau microjet, we show that the computed radial velocity shift for the medium-velocity component of the line profile as a function of distance from the jet axis is strikingly similar for rotating and non-rotating jet models. These findings lead us to put forward some caveats on the interpretation of the observed radial velocity distribution from a few outflows from young stellar objects, and we claim that these data should not be directly used as a doubtless confirmation of the magnetocentrifugal wind acceleration models.

Radial velocity

Precession

Line (geometry)

10.1051/0004-6361:20054110

Cite

Citations (43)

Space Science Reviews (2003)

A. H. Cerqueira E. M. de Gouveia Dal Pino

10.1023/a:1025577218042

Cite

Citations (4)

Facioscapulohumeral (FSHD1) and other forms of muscular dystrophy in the same family: is there more in muscular dystrophy than meets the eye?

Neuromuscular Disorders (2002)

Maria Manuela O. Tonini Maria Rita Passos‐Bueno A. H. Cerqueira Rita C.M. Pavanello Mariz Vainzof

Facioscapulohumeral muscular dystrophy

Proband

Dysferlin

Dystrophy

Limb-girdle muscular dystrophy

Muscle weakness

10.1016/s0960-8966(02)00014-7

Cite

Citations (9)

H$_2$ mass-velocity relationship from 3D numerical simulations of jet-driven molecular outflows

HAL (Le Centre pour la Communication Scientifique Directe) (2020)

A. H. Cerqueira B. Leflóch A. Esquivel P. R. Rivera-Ortíz C. Codella

Source

Cite

Citations (0)

ANÁLISE HISTÓRICA DA IRRADIAÇÃO GLOBAL NO MUNICÍPIO DE ILHÉUS/BA

Revista Brasileira de Energia Solar (2019)

A. H. Cerqueira Ronaldo Lima Gomes

Os dados para a irradiação solar global, disponibilizados pela Estação Automática de Coleta de Dados (PCD) operada pelo Sistema Integrado de Dados Ambientais (SINDA), foram utilizados para obter sua série histórica para o caso particular do município de Ilhéus, Bahia, no período compreendido entre os anos de 2001 a 2016. Com isto, obtivemos valores diários para a irradiação global incidente em uma superfície horizontal, HHOR, e comparamos estes valores com o esperado para o topo da atmosfera, HHOR,0. Com estes dois parâmetros calculamos o índice de claridade, KT, e mostramos o comportamento praticamente constante do seu valor médio ao longo de um ano para o município de Ilhéus, a despeito da grande dispersão (diária) encontrada para este índice. Em particular, mostramos que o índice de claridade diário médio para Ilhéus, neste período, é de KT = 0.46  0.13. Ao analisar a distribuição de KT usando os chamados filtros de Iqbal, mostramos que, de fato, Ilhéus possui majoritariamente dias que são parcialmente cobertos com nuvens. Ao se estudar a distribuição do índice de claridade com a época do ano, mostramos que esta tendência persiste. Propomos também a existência de uma correlação entre os índices de claridade obtidos para superfícies horizontal e inclinada, o que pode contribuir para previsão de geração de energia em unidades de microgeração fotovoltaicas em regiões onde existem determinações de KT.

10.59627/rbens.2019v10i1.248

Cite

Citations (0)

THE EFFECTS OF MAGNETIC FIELDS ON RADIATIVE COOLING JETS

Revista Mexicana de Astronomía y Astrofísica (2002)

E. M. de Gouveia Dal Pino A. H. Cerqueira

We here review the results of recent studies of magnetic eld eects on the structure and evolution of overdense, radiatively cooling, steady and pulsed jets, which were carried out with the help of fully three-dimensional MHD simulations. Three initial magnetic eld topologies are considered: (i) a helical and (ii) a longitudinal eld, both of which permeate the jet and the ambient medium, and (iii) a pure toroidal eld in the jet. Using a set of parameters that is particularly appropriate to protostellar jets, we examine the emission structure of the internal knots and the leading working surface, comparing our results with a nonmagnetic baseline and also with 2-D MHD calculations.

Radiative Cooling

Source

Cite

Citations (1)

Influence of the Hall effect on the mean field dynamo

AIP conference proceedings (2006)

M. J. Vasconcelos Alejandra Kandus A. H. Cerqueira

The magnetic field dynamo is a mechanism which occurs in several different environments, such as the interior of stars, accretion disks or the interstellar medium. Because of this diversity, the equations which describe its behavior should incorporate the peculiarities of such different regions. For example, particles in low ionized and strongly magnetized objects, such as protostellar accretion disks, should be subject to the Hall effect, which modifies the Ohm’s law. In this work, we study how the Hall effect alters the equations that govern the turbulent mean field dynamo. We derive the equations for the e.m.f, cross helicity and for the small and large scale magnetic helicities. We consider a two scale model in which turbulent is induced in a scale lS and the magnetic field is generated at a larger scale lL and the Hall effect is relevant in a intermediate scale lH. We obtain that even in the presence of Hall effect the mechanism responsible for the dynamo action is still the inverse cascade of magnetic helicity. As in previous results without the Hall term, the numerical solutions with Hall effect show an oscillatory behavior. However, the amplitude of the oscillations is smaller and the e.m.f. is damped earlier. This result confirms previous numerical simulations. We conclude that Hall dynamo theory should be taken into account in order to correctly describe the evolution of the magnetic field in low in low ionized media.

Solar dynamo

Magnetic helicity

Helicity

10.1063/1.2405960

Cite

Citations (0)

Shadows and Photoevaporated Flows from Neutral Clumps Exposed to Two Ionizing Sources

arXiv (Cornell University) (2006)

A. H. Cerqueira J. Cantó A. C. Raga Maria Vasconcelos

Neutral clumps immersed in HII regions are frequently found in star formation regions. We investigate here the formation of tail of neutral gas, which are not reached by the direct ionizing flux coming from two massive stars, using both an analytical approximation, that allows us to estimate the shadow geometry behind the clumps for different initial geometric configurations, and three-dimensional numerical simulations. We found a good agreement between both approaches to this theoretically interesting problem. A particularly important application could be the proplyds that are found in the Trapezium cluster in Orion, which are being photoevaporated primordially by the O stars theta-1 Ori C and theta-2 Ori A.

Star (game theory)

10.48550/arxiv.astro-ph/0605625

Cite

Citations (3)

CORRELATING THE INTERSTELLAR MAGNETIC FIELD WITH PROTOSTELLAR JETS AND ITS SOURCES

The Astrophysical Journal (2011)

C. G. Targon C. V. Rodrigues A. H. Cerqueira G. R. Hickel

This article combines new CCD polarimetric data with previous information about protostellar objects in a search for correlations involving the interstellar magnetic field. Specifically, we carried out an optical polarimetric study of a sample of 28 fields of 10 X 10 arcmin^2 located in the neighborhood of protostellar jets and randomly spread over the Galaxy. The polarimetry of a large number of field stars is used to estimate both the average and dispersion of the interstellar magnetic field (ISMF) direction in each region. The results of the applied statistical tests are as follows. Concerning the alignment between the jet direction and the interstellar magnetic field, the whole sample does not show alignment. There is, however, a statistically significant alignment for objects of Classes 0 and I. Regarding the interstellar magnetic field dispersion, our sample presents values slightly larger for regions containing T Tauri objects than for those harboring younger protostars. Moreover the ISMF dispersion in regions containing high-mass objects tends to be larger than in those including only low-mass protostars. In our sample, the mean interstellar polarization as a function of the average interstellar extinction in a region reaches a maximum value around 3% for A(V) = 5, after which it decreases. Our data also show a clear correlation of the mean value of the interstellar polarization with the dispersion of the interstellar magnetic field: the larger the dispersion, the smaller the polarization. Based on a comparison of our and previous results, we suggest that the dispersion in regions forming stars is larger than in quiescent regions.

Protostar

10.1088/0004-637x/743/1/54

Cite

Citations (20)

Milder course in Duchenne patients with nonsense mutations and no muscle dystrophin

Neuromuscular Disorders (2014)

Mayana Zatz Rita C.M. Pavanello Monize Lazar Guilherme Lopes Yamamoto Naila Cristina Vilaça Lourenço

Nonsense mutation

mdx mouse

10.1016/j.nmd.2014.06.003

Cite

Citations (4)