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.

Dr. Gustavo R. R. Soares, PhD in Astrophysics

Congratulations to the now Dr. Gustavo R. R. Soares, for a successful PhD thesis defense! 🎉🍾

The thesis is entitled “Accretion discs, jets, and black hole spins: a study of blazars” and was done under my supervision. The whole defense was entirely online, following the social distancing recommendations of the World Health Organization and the São Paulo State government, in order to ensure the safety of all involved with respect to COVID-19.

The defense lasted for almost five hours (!!), with the thesis committee members in two countries—Brasil and US—and in three states in Brasil: Pernambuco, Rio de Janeiro and São Paulo.

Gustavo presenting his thesis work

Thanks to Dr. Soares’s work, we now we know a bit more about the role of black holes in the universe, and how the supermassive ones power relativistic jets.

Gustavo will begin a postdoc at Oregon State University in the Fall. We are all wishing Gustavo a huge success for his future career!

Our thanks to the Brazilian science funding agencies CAPES, CNPq and FAPESP. Without them, this work would not have been possible.

Massive presence of the group at the Brazilian Astronomical Society Meeting

The Black Hole Group had a massive presence at the 43th meeting of the Brazilian Astronomical Society—Sociedade Astronômica Brasileira, SAB.

After Marta Volonteri’s review talk on the cosmic evolution of massive black holes, Fabio gave a presentation about the current status of his analysis of Fermi LAT observations of the Galactic Center—we are finishing the first paper of the series which should be submitted very soon.

After Fabio’s talk, we’ve had Ivan’s talk on his numerical hydrodynamical simulations of radiatively inefficient accretion flows and their winds.

Roberta Pereira presented her poster on applying deep learning to predict the future of accreting black holes, which are an extreme example of spatiotemporally chaotic systems.

Finally, Gustavo won one of the best poster prizes at the meeting, and was awarded a talk at the meeting. Wait, is that an award? 🙂

Gustavo Soares’s talk at the 43th SAB meeting.

New paper: Winds and feedback from supermassive black holes fed at low rates

We have a new paper out now on arXiv and submitted to the MNRAS: Winds and feedback from supermassive black holes accreting at low rates: Hydrodynamical treatment. This paper is the outcome of my MSc dissertation.

winds-arxiv

In this work we studied how accreting supermassive black holes generate winds that can potentially interact with the host galaxy. Our target was an active galactic nuclei (AGN) with very low accretion rates, like the famous M87*. Can these underfed systems generate powerful winds that will change the fate of the whole galaxy?

We performed diverse simulations of accretion disc flows around Schwarzschild black holes under an hydrodynamic treatment. Our simulations were some of the longest ones of our knowledge. The results show that some systems can create powerful thermally driven black hole winds that can be related to what we call “AGN feedback”. AGN feedback can be understood as the interaction between the ejected material/energy from the accretion flow and the host galaxy, this effect is crucial to understand galaxy evolution and currently it is a very active topic of research in astronomy. With this work we explored the possibility of thermally driven winds as a mechanism to explain this effect.

In the video below we show one of the simulations. On the top we have the gas density and each horizontal panel is the same disc but with different zoom levels, the scale is in Schwarzschild radius. On the bottom of the video we plot the wind efficiency. In practical terms, higher values here indicate stronger material ejection and production of more powerful winds.

For more details, please read our paper.

This work was supported in part by FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo) under grant 2017/01461-2 and grant 2016/24857-6.fapesp_logo-lowres

Imagem do buraco negro: repercussão na imprensa brasileira

Esta Quarta-feira, 10 de Abril de 2019, foi um dia que ficará para a história, como o dia em que conseguimos o impossível: a humanidade conseguiu fazer a primeira fotografia de um buraco negro.

Fabio e Rodrigo começamos o dia fazendo uma apresentação no IAG sobre a ciência do Event Horizon Telescope, e depois transmitimos a coletiva de imprensa da NSF. Nota: não fazemos parte da colaboração Event Horizon Telescope.

A partir daquele momento, houve uma gigantesca procura da imprensa pelo nosso grupo de pesquisa de buracos negros, para comentar sobre a incrível primeira fotografia de um buraco negro.

Nas mídias de vídeo, fomos procurados pela Band News e Globo News (Rodrigo) e Gustavo apareceu no AstroTubers.

Link para matéria na Band News (8 minutos em horário nobre!).

Gustavo no AstroTubers
Rodrigo na Globo News 1/2 (ao vivo, 19:45)

Link para matérias na Globo News (Rodrigo aparece nos 5:00 do vídeo) e aqui.

Link para vídeo no Jornal da Band

E tem mais: fomos procurados também pela Veja, Isto É, Revista Pesquisa FAPESP, Estadão, Jornal da USP e Fantástico.

Matéria de capa no Estadão com entrevista de Rodrigo.

Ficamos contente que o nosso grupo de pesquisa esteja realizando um papel importante de disseminação e clarificação da ciência para o público—afinal de contas, nossos recursos de pesquisa são custeados pelos impostos pagos pela população.