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July/October



1° Encontro Científico do ICRANet em Erevan – Armênia
"Black Holes: the largest energy sources in the Universe".
Resultados científicos mais relevantes

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Após a cerimônia de abertura, o Prof. Ruffini apresentou a palestra “Black Holes, Gamma-Ray Burst and Supernovae. The Leading Progress in Physics and Relativistic Astrophysics” sobre a história da descoberta dos GRBs, bem como sobre os resultados mais recentes de observação e de modelagem de GRBs. Também falou do recente progresso na compreensão da conexão entre GRBs e supernovas.
Neste congresso armênio, na seção sobre interação forte, os especialistas mundiais Christoph H. Keitel (Alemanha), Karen Hatsagortsyan (Armênia) e Antonino Di Piazza (Itália) do Instituto Max Planck (Heidelberg, Alemanha) apresentaram seus estudos em física nuclear, onde usam lasers intensos e fótons de alta energia por colisão de feixes de laser. Também fizeram uma revisão geral sobre a fenomenologia de campos magnéticos fortes.
Duas palestras em astrofísica de raios gama de alta energia foram dadas por Razmick Mirzoyan (Alemanha-Arménia) e Alessandro De Angelis (Itália). Mirzoyan mostrou resultados recentes de observações feitas pelo telescópio MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov Telescopes) de fontes galácticas (o remanescente de supernova W51 e a Nebulosa do Caranguejo), fontes extragalácticas (IC 310, MRK 412, etc) e destacou o atual status do CTA (Cherenkov Telescope Array). De Angelis apresentou resultados em astrofísica de raios gama de alta energia para energias relativamente baixas (em torno de 10 GeV) com detectores de Cherenkov. O grupo ICRANet, constituído por alunos EMJD (Doutoramentos Conjuntos Erasmus Mundus) e pelo corpo docente do ICRANet, apresentou resultados de seus estudos recentes em GRBs, em supernovas e nas conexões entre supernovas e GRBs. A física de estrelas de nêutrons, e os progressos recentes na área, foram discutidas por Jorge Rueda, Riccardo Belvedere e Kuantay Boshkayev. Além disso, Eckhard Strobel, Yuanbin Wu, Hendrik Ludwig e outros, apresentaram suas pesquisas no problema de campos electromagnéticos fortes, e discutiram todos os fenômenos e aplicações relevantes em física e astrofísica.
Paolo Giommi e Bruno Sversut, este estudante EMJD, apresentaram uma amostra de high synchrotron peaked blazars, os quais são interessantes para observações em TeV. Eles concluíram que a maioria deles seria detectado pelo próximo CTA, e alguns deles em estado de emissão ainda poderiam ser detectados pelos telescópios Cherenkov da geração atual. Prof Claus Laemmerzahl da Universidade de Bremen apresentou a palestra “Test particle motion in regular black hole space-times”.

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Trabalhos da Reunião “Zel'dovic-100”

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O grupo ICRANet recebeu todos os contributos para os trabalhos do Zel'dovic-100, realizado em Minsk (Bielorrússia) em março de 2004 (18 das sessões plenárias e 32 das sesões paralelas). Os trabalhos serão publicados no final do ano corrente nas edições especiais da revista Astronomy Reports (sessões plenárias) e da revista Nonlinear Phenomena in Complex Systems (sessões paralelas). Ambas revistas são indexadas na Scopus, Astronomy Reports é indexada também na Thomson Reuters. Editores das edições especiais: Sergei Kilin (Academia Nacional de Ciências da Bielorrússia), Remo Ruffini (Diretor do ICRANet) and Gregory Vereshchagin (ICRANet).




Publicação dos trabalhos do "13th Italian-Korean meeting on Relativistic Astrophysics"

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articiparam desse encontro, organizado a cada dois anos em Itália e na Coreia alternadamente (favor, acesse aqui) mais de 10 pessoas envolvidas no ICRANet os quais apresentaram seus trabalhos científicos. Esses trabalhos foram publicados recentemente na revista de referência <>. Para pré-visualização favor, acesse: http://link.springer.com/journal/40042/65/6/page/1




Colaboração entre o ICRANet e o Instituto A. Enstein de Potsdam

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O ICRANet, em parceria com o grupo de pesquisa do Professor. Hermann Nicolai do Albert Einstein Institute em Potsdam (Alemanha), lançou em julho o novo programa “Exact solutions in the supersymmetric General Relativity”. Mais uma nova colaboração adiciona-se à lista das temáticas do ICRANet no campo “Exact Solutions of the Einstein and Einstein-Maxwell equations”.
Objetivo principal é a construção dos mais exatos sólitons supergravitacionais.




Acordos recém assinados no Brasil, Itália e México

Nos meses de Julho e Agosto, o Prof. Ruffini assinou novos e importantes acordos com algumas das principais universidades do Brasil e México, prova do éxito da atuação diplomática do Diretor do ICRANet na América do Sul: no dia 1 de julho, em Niterói (RJ – Brasil) foi assinado o Acordo de colaboração ICRANet-UFF – Universidade Federal Fluminense); no dia 9 de Julho, na Cidade do México, foi assinado o Acordo com a UAM – Universidad Autónoma Metropolitana; no dia 26 de agosto, em Florianópolis, foi assinado o Acordo de colaboração com a UFSC – Universidade Federal de Santa Catarina; finalmente, no dia 29 de Agosto foi assinado o Acordo com a UFPE – Universidade Federal de Pernambuco.
Primeiro de agosto, em Roma, foi assinado o Acordo com o CNR – Centro Nazionale di Ricerche, liderado pelo Professor Luigi Nicolais.

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Agreement with the UAM
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Agreement with the UFSC
 
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Agreement with the UFPE
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Agreement with the CNR




Grande êxito de “A Noite dos Pesquisadores 2014”

Researchers' Night

Pelo segundo ano consecutivo, o ICRANet participou do programa nacional “A Noite dos Pesquisadores 2014”, uma atividade nacional que pretende levar as atividades de pesquisa ao alcance de todos. Na parte da manhã do dia 26 de Setembro, os cientistas do ICRANet conversaram com 150 estudantes explicando e falando sobre os trabalhos de pesquisa que estão realizando.
A sede do ICRANet manteve suas portas abertas a noite para o público: foi elaborado um intenso programa de visitas guiadas que permitiu aos interessados visitarem os lugares onde os pesquisadores do ICRANet estudam as estrelas e as leies que regem o Universo.
Além disso alguns cientistas do ICRANet apresentaram no prestigioso Aurum de Pescara um vasto programa de conferências e observações com o telescópio: o Professor Ruffini falou sobre “Supernovae, Gamma Ray Burst and Blacks Holes" e o Doutor Costantino Sigismondi apresentou a palestra “Supergiants Novae and Variables”; ao mesmo tempo os Doutores Luca Izzo e Costantino Sigismondi realizaram observações do Sol e das estrelas até meia-noite.




Delegação de estudantes dinamarqueses em visita ao ICRANet

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No dia 23 de outubro, uma delegação de 6 estudantes dinamarqueses provenientes da cidade de Svendborg visitou o Centro de Pesquisa ICRANet. Orientados pelo Professor Mads Fjeldvig Gammeltoft, os estudantes tiveram a oportunidade de conversar com o Diretor do Centro e assistir à palestra “Light and the exploration of the Universe” do Professor Gregory Vereshchagin, cientista pesquisador do ICRANet.




Apresentaçaõ do cartaz do Fourteenth Marcel Grossman Meeting - Roma, Itália, 12-18 de Julho de 2015

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Nos dias de 12 a 18 de junho de 2015,” será realizado em Roma, na Universidade “Sapienza” o encontro “Fourteenth Marcel Grossmann Meeting. Desde 1975, os encontros Marcel Grossmann têm sido organizados com a finalidade de criar oportunidades para estudar os mais recentes progressos nos campos da gravitação, relatividade geral e teorias relativísticas, para salientar os fundamentos matemáticos, as previsões físicas e os testes exprimentais. Os objetivos desses encontros seriam propiciar o intercâmbio científico entre os pesquisadores e cientistas no âmbito da compreensão da estrutura do espaço-tempo, e rever o estado dos experimentos atualmente em curso no âmbito dos testes das teorias gravitacionais de Albert Einstein no espaço como na terra.
No passado, realizaram-se os encontros em Trieste (1975 and 1979), Shanghai (1982), Roma (1985), Perth (1988), Quioto (1991), Stanford (1994), Jerusalém (1997), Roma (2000), Rio de Janeiro (2003), Berlim (2006), Paris (2009) e Estocolmo (2012). Os cientistas que estiverem interessados podem entrar em contato com qualquer membro dos Comitê organizador ou com a secretaria da conferência.
Essa edição do MG14 marca o Centenário das equações de Einstein, o Ano Intenacional da Luz 2015 organizado pela UNESCO, e o “Golden Jubilee of Relativistic Astrophysics”; todos esses eventos serão celebrados em ocasião do MG14 e das reuniões satélites em Armênia, Brasil, China, Alemanha, Índia, Israel, Coreia, México e Estados Unidos.
O programa científico, com sessões plenária e paralelas, está em costante evolução.
Para baixar o cartaz acesse: http://www.icra.it/mg/mg14/MG14_poster.pdf
Para o website acesse: http://www.icra.it/MG/mg14/
Contato: mg14@icra.it


ICRANet Faculty and Student’s Scientific Research articles

GRB 130427A and SN 2013cq: A Multi-wavelength Analysis of An Induced Gravitational Collapse Event

R. Ruffini, Y. Wang, M. Kovacevic, C.L. Bianco, M. Enderli, M. Muccino, A.V. Penacchioni, G.B. Pisani, J.A. Rueda
Accepted by ApJ

In the particle physics, the interaction between particles generates new particles, named as S-matrix. For instance, a pair of quark and anti-quark produces W/Z boson and Higgs boson, the outcome of electron and positron interaction could be a pair of muon and anti-muon, the duration of such interaction is fleeting, the above two reactions only take 10−26 s and 10−23 s respectively.
In the marco-scale astrophysics, some phenomena are apparently similar to the micro-scale particle physics, a famous example is the similarity of electron and blackhole, both can be completely characterized by only mass, electric charge, and angular momentum. Here in our new accepted Astrophysical Journal paper, we introduce a new celestial matrix, C-matrix, an analogue to the S-matrix (Fig.1). C-matrix depicts a binary system composed of one neutron star and one massive star as the initial state, and the products after about 100s interaction are one new neutron star and one black hole. The story of this process can be outlined as: The massive star undergoes a supernova and eject its massive shell, the companion neutron star accretes the ejecta until reaching its critical mass and collapses into a black hole, simultaneously an over critical electrical field is generated around the black hole and electro-positron plasma are produced from it, this plasma flow expands ultra-relativisticly and collides with the inter-stellar medium, which gives origin to the gamma-ray burst (GRB), GRB is considered as an energetic explosion which emits huge abundant photons, mainly the gamma-rays.
On April 27, 2013, such aforementioned event occurred and triggered Fermi satellite, later various satellites and telescopes joined the observation. This event was named as GRB 130427A, it is one of the few GRBs which has hundreds of seconds simultaneous data in the optical, X-ray and GeV emission, especially precious is its GeV emission, due to the long duration, high intensity and containing the highest energy photon (95.3 GeV) ever observed in GRBs.
We proceeded to make a multi-wavelength analysis. The high energy GeV emission appears to be detectable at the end of the prompt radiation phase(∼ 20s), when the fluence of X-ray and γ-ray of the prompt exponentially decrease and becomes transparent for GeV photons.
After 200s, the Lorentz factors of X-ray and GeV are very different, and their physical origin are necessarily different. The high energy can originate from the interaction of some of the physical components (e.g., neutron star and black hole) newly created in the C-matrix.

[fig1]

Figure 1: Three different matrices in fundamental physics. The first is the quark matrix leading to a Higgs boson. In the middle is the classical electron-positron pair matrix, generating an muon and anti-muon pair. The third matrix is the celestial one, which is considered in the present work. ∆t is the duration of intermediate state.

The interaction of the GRBs with the SN ejecta may well generate the X-ray emission and the associated thermal component. By analyzing the X-ray data from 195s to 461s, a crucial evidence was found, that adding a blackbody component could efficiently improve the fitting (Fig. 3), the obtained blackbody temperature is in the range of 0.3 KeV to 0.5 KeV, the radiation radius is deduced from about 7 × 1012 cm to 2.8 × 1013 cm, with the expansion speed at 0.8c, c is the speed of light. These above value is typical for the supernova ejecta accelerated by the collision with GRB outflow.
GCN 14526: The late X-ray observations of GRB 130427A by Swift-XRT clearly evidence a pattern typical of a family of GRBs associated to supernova (SN) following the Induce Gravitational Collapse (IGC) paradigm (Rueda & Ruffini 2012; Pisani et al. 2013). We assume that the luminosity of the possible SN associated to GRB 130427A would be the one of 1998bw, as found in the IGC sample described in Pisani et al. 2013. Assuming the intergalactic absorption in the I-band (which corresponds to the R-band rest-frame) and the intrinsic one, assuming a Milky Way type for the host galaxy, we obtain a magnitude expected for the peak of the SN of I = 22 - 23 occurring 13-15 days after the GRB trigger, namely between the 10th and the 12th of May 2013. Further optical and radio observations are encouraged.
After the first days observation, we found that the X-ray afterglow of GRB 130427A overlaps other GRBs induced by C-matrix (Fig.4), we concluded that this new GRB shared the same mechanism, which means a supernova is inevitable in the system though the optical signal is too weak too be observed, immediately we sent a letter to GCN on May 2, 2013, predicting that the optical R-band of a SN will reach its peak magnitude in about 10 days in the cosmological rest-frame on the basis of the IGC paradigm, and we encouraged observations.

[fig2]

Figure 2: Flux of first 700 s. Blue points are the Fermi-LAT high energy emission from 100 MeV till 100 GeV, grey dotted line represents the Fermi-GBM, from 10 keV to 900 keV, green dashed line represents the photons detected by Swift BAT from 10 keV to 50 keV, and red solid line is the soft X-ray Swift-XRT detection, in the range of 0.3 KeV to 10 KeV. From this figure, clearly the Fermi-LAT emission reaches highest fluence at about 20 s while the gamma-ray detected by Fermi-GBM releases most of the energy within the first 10 s.


[fig3]

Figure 3: Spectral fitting of three time intervals (196s - 246s, 246s - 326s, 326s - 461s) in Episode 3, data come from Swift-XRT (0.3 KeV - 10 KeV, without pile-up area). Black points are the deduced data, green dashed line presents the thermal component, blue long-dashed line is the power law component, and red line shows the combination of these two components. Clearly the flux of thermal component drops and the temperature decreases along the time.

[fig4]

Figure 4: Overlapping of GRB 130427A and GRB 060729. Green cross is the light curve of GRB 060729. Red triangle and orange dots represent the light curve of GRB 130427A respectively before and after May 2, 2013. The vertical line marks the time of 2 × 104 s which is the lower limit for the domain of validity of the Pisani relation prior to GRB 130427A.
Indeed, starting from May 13, 2013, the telescopes GTC, Skynet and HST discovered the signals from the type Ic supernova SN 2013cq.




Letter in collaboration with Pror. Fryer, Los Alamos:
Hypercritical Accretion, Induced Gravitational Collapse, And Binary-Driven Hypernovae

Chris L. Fryer, Jorge A. Rueda, Remo Ruffini
ApJ Letters 793, 36 (2014)

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The induced gravitational collapse (IGC) paradigm has been successfully applied to the explanation of the concomitance of gamma-ray bursts (GRBs) with supernovae (SNe) Ic. The progenitor is a tight binary system composed by a carbon-oxygen (CO) core and a neutron star (NS) companion. The explosion of the SN leads to hypercritical accretion onto the NS companion which reaches the critical mass, hence inducing its gravitational collapse to a black hole (BH) with consequent emission of the GRB. The first estimates of this process were based on a simplified model of the binary parameters and the Bondi-Hoyle-Lyttleton accretion rate. We present here the first full numerical simulations of the IGC phenomenon. We simulate the core-collapse and SN explosion of CO stars to obtain the density and ejection velocity of the SN ejecta. We follow the hydrodynamic evolution of the accreting material falling into the Bondi-Hoyle surface of the NS all the way up to its incorporation to the NS surface. The simulations go up to BH formation when the NS reaches the critical mass. For appropriate binary parameters the IGC occurs in short timescales (100-1000s) owing to the combined effective action of the photon trapping and the neutrino cooling near the NS surface. We also show that the IGC scenario leads to a natural explanation for why GRBs are associated only to SN Ic with totally absent or very little helium.




Semiclassical pair production rate for time-dependent electrical fields with more than one component: WKB-approach and world-line instantons

Strobel, Eckhard; Xue, She-Sheng
Nuclear Physics B 886, 1153 (2014)

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Description: The Schwinger-effect describes how pairs of electrons and positrons can be produced from the vacuum with the help of a very strong electric field. While this effect is believed to play a important rule in astrophysics, especially for gamma ray burst, it has never been observed directly in a laboratory. The reason for this is that currently one can not produces the field strengths which are necessary to produce a measurable number of pairs. This might change with the construction of new high energy laser systems, like the Extreme Light Infrastructure (ELI).
It has recently been shown that pair creation rate changes over several orders of magnitude depending on the form of the laser pulse. To design an experiment in which Schwinger pair creation can be measured directly it is substantial to understand this dependence. While a lot of computations can be performed numerical it is worthwhile to continue to study approximate analytical methods to strengthen this understanding.
In the paper we generalize two well-known analytical methods, namely the WKB and the world line instant on method, to fields which have more than one time-dependent component. The comparison of the two methods shows when to best use which of the methods. The generalizations enables us to find a analytic solution for the momentum spectrum of the produced pairs in a rotating electric field. As displayed in Figure no pairs are produced which have zero momentum. This is a big difference to the known cases of one-component fields, where most pairs are produced with zero momentum. Since the rotating electric field is a approximation for the field in the anti-node of a circularly polarized standing wave, which can be produced in laser experiments, the characteristic shape of this momentum spectrum might help to distinguish the pairs produced by the Schwinger process from those produced due to other strong field effects.




Submitted Articles:

Induced Gravitational Collapse At Extreme Cosmological Distances: The Case Of Grb 090423
R. Ruffini, L. Izzo, M. Muccino, G.B. Pisani, J.A. Rueda, Y. Wang, C. Barbarino, C.L. Bianco, M. Enderli, M. Kovacevic
A&A 569, A39 (2014)

The Genuine Short Grb 090227b And The Disguised By Excess Grb 090510
M. Muccino, C.L. Bianco, L. Izzo, Y. Wang, M. Enderli, M. Kovacevic, G.B. Pisani, A.V. Penacchioni, R. Ruffini
Gravitation and Cosmology, 20, 197 (2014)

On The Core-Halo Distribution Of Dark Matter In Galaxies
Remo Ruffini, Carlos Argüelles, Jorge A. Rueda
Submitted to Phys. Rev. Lett.

Just Published Articles:

Semiclassical Pair Production Rate For Time-Dependent Electrical Fields With More Than One Component: Wkb-Approach And World-Line Instantons
Strobel, Eckhard; Xue, She-Sheng
Nuclear Physics B 886, 1153 (2014)

Transparency Parameters From Relativistically Expanding Outflows
Bégué, D.; Iyyani, S.
ApJ 792, 42  (2014)

Dynamical Instability Of White Dwarfs And Breaking Of Spherical Symmetry Under The Presence Of Extreme Magnetic Fields
J. G. Coelho, R. M. Marinho, M. Malheiro, R. Negreiros, D. L. Cáceres, J. A. Rueda, R. Ruffini
ApJ 794, 86 (2014)

Are The Most Super-Massive Dark Compact Objects Harbored At The Center Of Dark Matter Halos?
Carlos R. Argüelles, Remo Ruffini
Essay selected for Honorable mention 2014 by the Gravity Research Foundation

Strangeness Content Of Neutron Stars With Strong Sigma-Hyperon Repulsion
M. Razeira, A. Mesquita, C. A. Z. Vasconcellos, R. Ruffini, J. A. Rueda, R. O. Gomes
Astronomische Nachrichten 335, 739 (2014)

Effective Field Theory For Neutron Stars With Strong Sigma--Hyperon Repulsion
M. Razeira, A. Mesquita, C. A. Z. Vasconcellos, R. Ruffini, J. A. Rueda, R. O. Gomes
Astronomische Nachrichten 335, 733 (2014)

A search for Fermi bursts associated with supernovae and their frequency of occurrence
Kovacevic, M.; Izzo, L.; Wang, Y.; Muccino, M.; Della Valle, M.; Amati, L.; Barbarino, C.; Enderli, M.; Pisani, G. B.; Li, L.
Astronomy & Astrophysics, Volume 569, id.A108, 6 pp. (A&A Homepage)

 
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