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!

Douglas joins the group

Hello!

My name is Douglas Ferreira Carlos and i’m a physics graduate at IF-USP. I’ll be starting my master’s degree in the Black Hole Group at IAG-USP under the supervision of Prof. Rodrigo Nemmen.

Since I was a kid I’ve always been interested in understanding the underlying principles of how the universe works and in questioning the claims that were previously taken as given, much to the annoyance of the less scientifically minded adults around me. Later I got the chance to answer some of these questions as an physics undergrad at the Universidade de São Paulo while raising many others, and now I’m humbled to have received the opportunity to keep asking and to keep discussing ways of expanding our collective knowledge!

That being said, there is no better way of advancing knowledge than by working on the frontier of what is known, and there are few things in the universe that are as mysterious to us today as black holes are. So I expect that by studying the observations made by the Fermi Gamma-ray Space Telescope we’re able to gain some insight into the physics that takes place close to these very extreme and curious objects.

Bolsa de doutorado direto FAPESP

Está disponível uma bolsa de doutorado direto FAPESP, para trabalhar no Grupo de Buracos Negros do Prof. Rodrigo Nemmen no IAG-USP, dentro do Projeto Jovem Pesquisador FAPESP “O Universo Extremo: Buracos Negros e o Telescópio Fermi“.

O projeto a ser desenvolvido é na área de astrofísica de altas energias, envolvendo observações em raios gama de buracos negros supermassivos com o Telescópio Espacial Fermi. O trabalho envolverá o estudante em colaborações internacionais do Prof. Nemmen.

A bolsa é livre de impostos e a FAPESP oferece apoio para os custos de mudança. O salário inicia em R$ 2043/mês, chegando a R$ 3726/mês no último ano de doutorado. A Reserva Técnica para participação em eventos, compra de material etc é de 30% do valor anual da bolsa (R$ 13414/ano).

Os candidatos interessados deverão entrar em contato por email com o Prof. Rodrigo Nemmen para entrevista, onde serão discutidos: • experiência em computação e pesquisa do candidato • motivação para fazer pós-graduação • redação • conhecimentos básicos em (astro)física. Os candidatos devem incluir no e-mail:

  • Histórico escolar de graduação (e de pós-graduação, se houver)
  • Link para o CV Lattes
  • Um ou dois contatos de referências

O candidato deverá passar primeiro o processo seletivo para o programa de Doutorado Direto em Astronomia do IAG-USP, com inscrições até 25 de Junho de 2020. Potenciais interessados também podem entrar em contato com o Prof. Nemmen para tirarem dúvidas, antes de se candidatarem ao programa de pós-graduação em Astronomia do IAG-USP.


One FAPESP PhD scholarship is available in the Black Hole Group of Prof. Rodrigo Nemmen at IAG-USP, within the Projeto Jovem Pesquisador FAPESP “The Extreme Universe: Black Holes And The Fermi Telescope”. The PhD project is in the field of high-energy astrophysics, involving the analysis of Fermi Large Area Telescope gamma-ray observations and associated physics. The work will involve the student in the scientific collaborations of Prof. Nemmen.

The salary is tax-free, and the funding agency provides relocation funding. The salary begins at R$ 2043/month, reaching R$ 3726/month in the last year of the graduate program. The scholarship includes funds for attending events in the amount of R$ 13414/year.

Candidates should contact Prof. Rodrigo Nemmen. If short-listed, they will be interviewed by the PI where they will be asked to discuss their: • research and computational experience • motivation for pursuing graduate school • writing skills • (astro)physics knowledge. The candidates should include in their e-mail:

  • Undergraduate transcripts (and graduate, if available)
  • Curriculum vitae
  • One or two reference contacts

The candidate must be accepted in the selection process for the programa de Doutorado Direto em Astronomia do IAG-USP (deadline: June 25, 2020). Candidates who are interested and have any questions should contact Prof. Nemmen.

Bolsa de mestrado FAPESP

Está disponível uma bolsa de mestrado FAPESP, para trabalhar no Grupo de Buracos Negros do Prof. Rodrigo Nemmen no IAG-USP, dentro do Projeto Jovem Pesquisador FAPESP “O Universo Extremo: Buracos Negros e o Telescópio Fermi“.

O projeto a ser desenvolvido envolve análise de observações em raios gama de buracos negros supermassivos com o Telescópio Espacial Fermi. O trabalho envolverá o estudante em colaborações internacionais do Prof. Nemmen.

A bolsa é livre de impostos e a FAPESP oferece apoio para os custos de mudança. O salário inicia em R$2043/mês. A Reserva Técnica para participação em eventos, compra de material etc é de 10% do valor anual da bolsa (R$2452/ano).

Os candidatos interessados deverão entrar em contato por email com o Prof. Rodrigo Nemmen para entrevista, onde serão discutidos: • experiência em computação e pesquisa do candidato • motivação para fazer pós-graduação • redação • conhecimentos básicos em (astro)física. Os candidatos devem incluir no e-mail:

  • Histórico escolar de graduação
  • Link para o CV Lattes
  • Um ou dois contatos de referências

O candidato deverá passar primeiro o processo seletivo para o programa de Mestrado em Astronomia do IAG-USP, com inscrições até 25 de Junho de 2020. Potenciais interessados podem entrar em contato com o Prof. Nemmen para tirarem dúvidas, antes de se candidatarem ao programa de pós-graduação em Astronomia do IAG-USP.

Artur defends his MsC dissertation

The black hole group has a new master: Artur Vemado defended his MsC dissertation, entitled “radiative cooling and state transitions in stellar mass black holes”. The defense was very successful.

Here, Artur reported his numerical simulations of black hole accretion flows where he incorporated radiative cooling (with some approximations otherwise the problem is essentially intractable!). We observe the self-consistent emergence of a hot corona enveloping a cold thin accretion disk. Artur quantified the inner radius of the thin disk, the size of the corona, and how these properties respond to varying the mass accretion rate onto the black hole. The resulting simulated black holes are similar to observations of stellar mass black holes in binary systems.

We are looking forward to reporting these exciting results on the emergence of the corona (not the covid-19!) and truncated disk in an upcoming publication.

Many thanks to FAPESP funding through grant 2017/25710-1.