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Visitor on May and June

Raniere de Menezes obtained his PhD in our group, and after doing a postdoc in Germany he will be visiting our group on May and June. Raniere will be working on different subjects involving gamma-ray astronomy, AGNs and (surprise) stellar clusters. We are a black hole group, but we welcome diversity in all its aspects — including the diversity of science subjects. Welcome back, Raniere!

Acompanhamos o anúncio da primeira imagem de Sgr A*

O dia 12 de Maio foi cheio de emoção em nosso grupo. Foi revelada ao mundo pela colaboração Event Horizon Telescope (EHT) a primeira imagem de Sgr A*, o buraco negro supermassivo que habita o centro da Via Láctea. É a primeira detecção direta do buraco negro da nossa galáxia. Esse resultado em conjunto com a imagem do buraco negro supermassivo M87*, divulgado pela mesma colaboração em 2019, impacta ao confirmar diretamente a existência de buracos negros no centro de galáxias e abre portas para testar a física nesses ambientes extremos.

A primeira imagem da sombra de Sgr A*, o buraco negro supermassivo da Via Láctea. A imagem foi produzida pela colaboração do Event Horizon Telescope (EHT). Crédito: EHT Collaboration.

Para acompanhar o anúncio em tempo real divulgado pela National Science Foundation (NSF) o Black Hole Group organizou um evento no Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG) da USP. O evento contou com algumas palavras introdutórias do Prof. Rodrigo Nemmen, seguida por uma apresentação acerca de Sgr A* dada pelo mestrando Lucas Siconato, que estuda com o telescópio espacial Fermi a região de Sgr A*. Em seguida, o Prof. Nemmen deu uma visão geral sobre o Event Horizon Telescope e as expectativas do que seria anunciado.

“Sagitário A* é um buraco negro supermassivo que a gente pode chamar de nosso.”

Lucas Siconato, mestrando do grupo que trabalha com o telescópio espacial Fermi a região de Sgr A* em raios-gama.
Grupo reunido em comemoração a imagem de Sgr A*. Da esquerda para direita: Raniere de Menezes, Ivan Almeida, Pedro Motta, Catarina Aydar, Roberta Duarte, Douglas Carlos, Rodrigo Nemmen, Matheus Branco e Lucas Siconato.

A Repercussão do evento contou com cobertura da mídia nacional. Durante as entrevistas, ficou em destaque a pesquisa da doutoranda Roberta Duarte, cujo trabalho é pioneiro ao aplicar inteligência artificial para simular buracos negros interagindo com a sua vizinhança.

A doutoranda do grupo Roberta Duarte concedendo entrevista ao Jornal Nacional. A sua pesquisa pioneria que alia inteligência artificial a buracos negros ficou em destaque.

Trabalho de doutoranda do grupo é capa do Jornal da USP

Os resultados do projeto de mestrado de Roberta Duarte, atual doutoranda no Grupo de Buracos Negros, foi destaque no Jornal da USP. A pesquisa consistiu da aplicação pioneira de inteligência artificial para simular um buraco negro interagindo com o seu meio ambiente.

Capa do Jornal da USP com o destaque para a pesquisa de Roberta Duarte, doutoranda no Grupo de Buracos Negros.

O artigo reportando os resultados da pesquisa foi recentemente aceito para publicação na revista MNRAS.

Parabéns Roberta pela mais do que merecida repercussão do trabalho!

Mapa do céu em raios gama: Threads no twitter e papel de parede

Para quem desejar mais informações de forma sucinta sobre o mapa mais detalhado já feito do céu em raios gama, preparado pelo nosso grupo usando treze anos de observações do Telescópio Espacial Fermi, vejam as threads abaixo.

Quer usar a nossa imagem como papel de parede do seu smartphone ou PC? Siga os links abaixo.

A gamma-ray sky map!

The gamma-ray sky map produced using Fermi Space telescope observations from August 2008 to May 2021. Credit: D. Carlos, L. Siconato, R. de Menezes, R. Nemmen (Univ. de Sao Paulo).

The Black Hole Group is part of the Fermi LAT collaboration. The Fermi collaboration is a group of scientists that uses observations taken with the Fermi Gamma-ray Space Telescope, a telescope devoted to the observation of the gamma-rays:  the highest-energy form of light, and uses this to study different astronomical sources. Among the sources studied are, for example, black-hole systems, supernova remnants, and merging neutron stars.

Now, the Fermi telescope was launched on 11 June 2008, and until today it is still capturing high energy photons and giving us a large amount of data about the universe. As a way to better visualize the gamma-ray sky, Douglas Carlos, Lucas Siconato, and Raniere Menezes produced the above image.

To produce this, we used data with sources from all the sky collected by the Fermi telescope, with the beginning of the observation being in August 2008 and the ending in May of 2021. With this data, our group members did a split using the photon energy as a criterion. The first energy range was chosen to be from 100MeV to 1GeV. The second one was from 1GeV to 10GeV, and the last one has a range initiating in 10GeV and ending in 1TeV. Each one of these energy ranges has been assigned to a color from the RGB system that resulted in this incredible image when put together! When a source is mostly red, we have most of its photons belonging to the first energy range talked above. When a source is mostly green, its photons majority belong to the second energy range discussed, while a source that is mostly blue has the majority of its photons belonging to the last energy range. Beyond the fact that the sky seen in gamma rays harbors information from the light that is billions of times more energetic than the visible one, an image done in the configuration discussed above gives us information about each one of the sources’ emissions using colors. The colors make the image work like a map of the sky!

To understand a little better what you are seeing, you have to know that: each one of the points present in this image is a source whose Fermi Space Telescope has observed gamma light in the last 13 years. The central and very bright part is the galactic plane. It has a lot of diffuse emission of gamma rays, as one can see by the absence of point sources in this part. Another interesting feature that is possible to see is the Fermi bubbles. These bubbles have as an origin the central part of the Milkyway (faint blue glow at the center of the image) and are expanded to about 25 thousand light-years above and below the galactic center.

Now, an approach to think about this image is the one that we realize that each one of these sources has its own scientific potential and keeps precious information about nature and how it works! Also given enough time, it should be studied and understood. However, a complementary approach to think about it (and that someone would hardly say that it is not right) is to just realize how pretty and incredible the gamma-ray sky can be! Right?

Doutoranda do grupo tem texto publicado no blog da Folha de São Paulo

O texto com o título “Como os robôs superaram os humanos no xadrez?” foi publicado hoje no blog da Folha de São Paulo. O texto tem como assinatura a doutoranda do grupo, Roberta Duarte, que trabalha desenvolvendo métodos de inteligência artificial, mais especificamente o uso de deep learning, para compreender a física de buracos negros.

No texto, Roberta escreveu sobre como a inteligência artificial vem crescendo ao longo dos anos, desde quando Alan Turing apresentou seu paper Computing Machinery and Intelligence em 1950. E como, desde Turing, a inteligência artificial tem sido usada para aprender a jogar xadrez e competir com humanos. Ela descreve sobre como ocorreu a evolução dessas máquinas até os dias de hoje, na qual a campeã mundial é a AlphaZero desenvolvida pela empresa DeepMind.

Inteligência artificial está começando a ser usada para o desenvolvimento da Astrofísica como técnicas e métodos que contribuem para análise de dados, simulações e classificações de objetos astronômicos.

No grupo, recentemente, submetemos dois artigos que utilizam do método deep learning para fitar SEDs de AGNs com baixa luminosidade e obter a primeira simulação de buraco negro por uma inteligência artificial. Os artigos estão disponíveis no arXiv.

Link para leitura: https://cienciafundamental.blogfolha.uol.com.br/2021/04/07/como-os-robos-superaram-os-humanos-no-xadrez/

New organizer for journal club

Big news for our beloved black hole journal club meetings! Ivan will be now the new organizer of this important event in our department.

Fabio Cafardo was in charge of organizing the JC between 2016 and February 2021. Since he is graduating very soon, we now welcome Ivan Almeida to the important role of being the JC organizer. Thanks Fabio for being such a fantastic organizer, paying attention to keeping it on time, asking a lot of questions and making it overall fun! We will miss you.

Welcome Ivan!

Stellar-mass black holes welcome Pedro!

Hi everyone!

My name is Pedro Naethe Motta and I’m a graduate (M.Sc.) student at IAG – USP. I’ve recently graduated in physics at Universidade Federal Fluminense (UFF) in beautiful Rio de Janeiro.

As most undergraduate physics students, I started my journey aiming to understand and study astrophysics. At first, I didn’t have the chance to do that, so I worked in a project about “chaotic dynamical systems” in the mathematics department, deviating from the original plan.

In the meantime, I found out that I didn’t want to pursue this academical journey. I undertook a semester in General Relativity and reached out to my professor, who gave me the opportunity to work and build my undergraduate thesis in astrophysics. My thesis was about the tidal effects in a neutron stars’ binary system and how these effects can help to unravel mysteries of how matter behave in neutron stars’ interior. Since then, I’m passionate about General Relativity and astrophysics.

I’m recently starting my journey at the IAG’s Black Hole Group, studying state transitions in black hole binaries using General Relativity Magnetohydrodynamics (GRMHD) under the supervision of Professor Rodrigo Nemmen.

New grad student in the group: Lucas

Hello!

My name is Lucas Augusto L. Siconato and I’m a physics graduate at IFGW-UNICAMP. Right now, I’m beginning my master’s degree at IAG-USP under the supervision of professor Rodrigo Nemmen and being very honest: I’m very excited about this.

I believe that throughout my life I have been interested in astronomy, it is an incredible theme and we have a lot to learn about it yet. Because of that, since the beginning of my undergraduate studies, I tried to learn several subjects related to this topic and it couldn’t have been a better experience and I believe that this was what brought me here and helped me in the decision of being part of the Black Hole group.

Now, concerning the things that make up the universe, black holes are certainly among the most fascinating ones. They are breathtaking! I am sure that studying them will be both interesting and challenging, but I am extremely motivated to understand them a little better and get some insights about their physics considering the observations made by the Fermi Gamma-ray Space Telescope. I will be studying the low luminosity active galaxy nuclei and hope to learn some intriguing things about them!