Rita C. Anjos

Assistant Professor, doctor of physics

Hello!

I am an Astrophysics Professor working at the Federal University of Parana - Sector Palotina, Parana State/Brazil. My research group studies propagation of cosmic rays, multi-messenger particles and acceleration mechanims of cosmic rays. I have been a member of the Pierre Auger Cosmic Ray Observatory, in Malargue, Argentina, since 2014 and a member of the Cherenkov Telescope Array Observatory - CTA since 2015. In 2020 I won the Program for Women in Science award, promoted by L'Oreal Brasil, Unesco Brazil and the Brazilian Academy of Sciences. In 2021 I became an affiliate member of the Brazilian Academy of Sciences.

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Education.

  • 2003-2007

    Undergraduate studies (Physics), Brazil

    State University of São Paulo. Instituto de Biociências, Letras e Ciências Exatas de São José do Rio Preto. Supervisor: Elso Drigo Filho.

  • 2007-2009

    Master in Physics, Brazil

    University of São Paulo. Instituto de Física de São Carlos. Supervisor: Luis Agostinho Ferreira.

  • 2010-2014

    Ph. D. in Physics (Astrophysics), Brazil

    University of São Paulo. Instituto de Física de São Carlos. Supervisor: Luiz Vitor de Souza Filho.

  • 2019

    Junior Visiting Professor, EUA

    Institute for Theory and Computation (ITC) - Harvard-Smithsonian Center for Astrophysics.

Recent Research Projects.

The dynamics of ultra-high energy cosmic rays and black holes

The present project aim in developing a framework to correlate the details of the accretion mechanism in black holes to the production of UHECR, electromagnetic and gravitational waves.

The Blandford-Znajek mechanism, which explains the extraction of energy from the rotating black hole by the disk magnetic field, is going to be fully considered in the production of UHECR for the first time. The energy accumulated in the updated accretion mechanism is going to be used as an input to simulate the acceleration of particles in the jets of AGNs providing an estimate to the total kinetic power available in the source (energy balance). At this stage, the total kinetic power will be used to plot correlations among the spectra of gravitational waves, electromagnetic waves and the luminosity of UHECR (outflows). In summary, the present project aim in developing a framework to correlate the details of the accretion mechanism in black holes to the production of UHECR, electromagnetic and gravitational waves.

Funding:

Serrapilheira Institute

Ultra high energy cosmic rays acceleration and black holes

The main objective is to investigate the dynamics on particle acceleration from black holes endowed with simulations of the jets of extragalactic Active Galactic Nucleus (AGNs).

High Energy Physics and Astroparticle has as scientific focus the theoretical and experimental study of particle physics, within the environment the experiments in terrestrial laboratories and the study of their consequences in extremely energetic process occurring in the cosmos. In this work, I intend to study the theory on particle acceleration and magnetic field with simulations of jets of extragalactic sources and radiation fields on the way from the source to Earth. The main objective is to investigate the dynamics on particle acceleration from black holes endowed with simulations of the jets of extragalactic Active Galactic Nucleus (AGNs) in order to calculate observables and correlations among the spectra of cosmic rays and gamma rays, magnetic field quantities and the luminosity of ultra high energy cosmic ray emission (or gamma ray bursts).

Funding:

CNPq Agency

Novos Arranjos de Pesquisa e Inovação (NAPI) - Extreme Phenomena of the Universe

The group (NAPI) on Extreme Phenomena of the Universe aims to expand and consolidate the Brazilian presence in the areas of Astronomy, Cosmology and Gravitation on the international scene.

High Energy Physics and Astroparticle has as scientific focus the theoretical and experimental study of particle physics, within the environment the experiments in terrestrial laboratories and the study of their consequences in extremely energetic process occurring in the cosmos. In this work, I intend to study the theory on particle acceleration and magnetic field with simulations of jets of extragalactic sources and radiation fields on the way from the source to Earth. The main objective is to investigate the dynamics on particle acceleration from black holes endowed with simulations of the jets of extragalactic Active Galactic Nucleus (AGNs) in order to calculate observables and correlations among the spectra of cosmic rays and gamma rays, magnetic field quantities and the luminosity of ultra high energy cosmic ray emission (or gamma ray bursts).

Funding:

CNPq Agency

Multimessenger emission from source models of Ultra high energy cosmic rays

The target of this project is to study the propagation of charged particles, gamma rays and neutrino through the radiation and magnetic fields of the universe as a tool to understand the mechanisms operating in the extrema conditions.

The production of the most energetic particles in the Universe is one of the misteries in modern science. The acceleration mechanisms of particles in astronomical sources are unknown and recente results reveals the need of an multimenssager approach in order to solve the main questions. This research project aims to explore some of the open questions in the astroparticle physics working in close relation to the data measured by the Pierre Auger and Cherenkov Telescope Array Observatories. The target of this project is to study the propagation of charged particles, gamma rays and neutrino through the radiation and magnetic fields of the universe as a tool to understand the mechanisms operating in the extrema conditions.

Funding:

CNPq Agency

Neutrino cosmology and implications in cosmic ray physics

The origin of neutrinos and high-energy gamma can lead us to the source of cosmic rays. The proposed project intends to describe mechanisms involved in the correlation between charged nuclei and accelerated multi-messenger particles from astrophysical sources.

The origin of neutrinos and high-energy gamma can lead us to the source of cosmic rays. Gravitational energy released by the accumulation of matter near neutron stars and black holes accelerates the activity of protons or heavier nuclear nuclei, which later interact with the gas or cosmic background radiation, producing neutrinos and secondary particles. The proposed project intends to describe mechanisms involved in the correlation between charged nuclei and accelerated multi-messenger particles from astrophysical sources.

Funding:

CNPq Agency

Astronomy in the multi-messenger era and female participation. Quo Vadis?

In Brazil, the percentage of women scientists working in STEM is approximately 30%. This project aims to strengthen the insertion of women scientists in Astronomy. In the long term, the project will contribute to the inclusion and improvement of gender equality in the State of Paraná.

Currently, in Brazil, the percentage of women scientists working in STEM (Acronym in English: Science, Technology, Engineering, and Mathematics) is approximately 30%. This project aims to strengthen the insertion of women scientists in Astronomy. In the long term, the project will contribute to the inclusion and improvement of gender equality in the State of Paraná.

Funding:

CNPq Agency

Prizes, fellowships, grants and funding.

  • 2022

    Coimbra Group Schorlarship Programme - 2022

  • 2022

    Regular Associate of the ICTP (International Centre for Theoretical Physics) - (2023 - 2028)

  • 2021

    Araucaria Foundation - Cherenkov Telescope Array: Construction and First Discoveries (2021 - 2025), research support, 200 kUS$

  • 2021

    Affiliate member of the Academy Brazilian of Science (2021 - 2025)

  • 2020

    L’Oréal Women in Science/Brazil –UNESCO – Academy Brazilian of Science, award, 10 kUS$

  • 2020

    Research Fund UFPR, research support, 2k US$

  • 2019

    Research Stays for University Academics and Scientists – DAAD, scholarship, 13k US$

  • 2018

    Brazilian National Research Council, scholarship: Junior Visiting Professor, 21 kUS$

  • 2018

    CNPq (Council for Scientific and Technological Development) Research Productivity Fellow (PQ) – Level 2, 11 kUS$

  • 2017

    Serrapilheira Institute, research support, 33 kUS$

  • 2017

    Fulbright Junior Faculty Member Award, 12 kUS$

  • 2016

    Brazilian National Research Council, research support, 1.5 kUS$

  • 2016

    UFPR Fund of Academical Development support, 1 kUS$

  • 2014

    Brazilian National Research Council, research support, 3.5 kUS$

  • 2010

    Brazilian National Research Council, scholarship, 40 kUS$

  • 2007

    Brazilian National Research Council, scholarship, 10 kUS$

  • 2004

    Brazilian National Research Council, scholarship, 3 kUS$

Recent Publications.

An updated view and perspectives on high-energy gamma-ray emission from SGR J1935+2154 and its environment

Jaziel G. Coelho, Luana N. Padilha, Rita C. dos Anjos, Cynthia V. Ventura and Geanderson A. Carvalho. JCAP 10 041 2022

In one of our previous articles, we investigated the contribution to high-energy and very high-energy gamma-ray emission (VHE, E > 100 GeV) due to cosmic-ray acceleration of SNR G57.2+0.8 hosting SGR J1935+2154 using the GALPROP propagation code. However, follow-up observations of SGR 1935+2154 were made for 2 hours on April 28, 2020, using the High Energy Stereoscopic System (H.E.S.S.). We obtain a hadronic model that confirms the results discussed by H.E.S.S. . This leads to an optimistic prospect that cosmic ray gamma rays from SGR J1935+2154 can contribute to the overall gamma energy density distribution and in particular to the diffusion gamma rays from the Galactic center.

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Ultra-High-Energy Particles at the Border of Kerr Black Holes Triggered by Magnetocentrifugal Winds

Carlos H. Coimbra-Araújo Rita C. dos Anjos. Galaxies 10(4) 8 2022

The source, origin, and acceleration mechanisms of ultra-high-energy cosmic rays (UHECR) (E>1020 eV, beyond the GZK limit) remain uncertain and unclear. The main explanations are associated with particular mechanisms, such as the Fermi mechanism, in which charged particles could be accelerated by clouds of magnetized gas moving within our Galaxy, or by the magnetic reconnection of field lines at, e.g., the core of high-energy astrophysical sources, where the topology of the magnetic field is rearranged and magnetic energy is converted into kinetic energy. In the present work, we propose that charged particles can be accelerated to ultrahigh energies in marginally bound orbits near extreme rotating black holes and could be triggered by collisions of magnetocentrifugal winds; the accretion disk surrounding the black hole would provide such winds. The ultra-high-energy process is governed by the frame-dragging effects of the black hole spacetime.

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High-energy gamma-ray emission from SNR G57.2+0.8 hosting SGR J1935+2154

Rita C. dos Anjos, Jaziel G. Coelho, Jonas P. Pereira and Fernando Catalani. JCAP 10 023 2021

In this paper, we obtain the contribution to the high energy and very high-energy gamma-ray (VHE, E > 100 GeV) emission due to cosmic-ray acceleration from SNR G57.2+0.8 hosting the Soft Gamma Repeater (SGR) J1935+2154 with the use of the GALPROP code. To do so, we take into account the SNR + SGR association as a single source close to the Galactic center. We propose that the above setting can provide a more comprehensive scenario for the generation of GeV-TeV gamma-rays. We also discuss the contribution from the SNR G57.2+0.8 and SGR J1935+2154 region to the diffusive TeV energy gamma-ray emission from the Galactic center.

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Galactic Center as an efficient source of cosmic rays

Rita C. dos Anjos and Fernando Catalani. Phys. Rev. D 101, 123015, 2020

Based on a diffusion/reacceleration model, we use the galprop software to solve the diffusion equation for the cosmic rays and compare the results with the cosmic-ray spectrum, motivated by the relationship between several energetic sources at the Galactic Center and the generated diffuse GeV-TeV gamma rays. We calculate the cosmic ray distribution, gamma-ray flux from the Galactic Center and explore its contribution on the spectrum and chemical composition of cosmic rays observed on Earth. We also discuss the effects of nuclei interactions with different interstellar gas models.

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Acceleration of charged particles from near-extremal rotating black holes embedded in magnetic fields

Carlos H. Coimbra-Araújo and Rita C. dos Anjos. Class. Quantum Grav. 38 015007 2020

Here it will be considered that particles initially moving around some particular orbit may be perturbed by a kick along the θ direction, giving rise to other possible orbits. We confirm the possibility that ultra high energy cosmic rays would be produced at the very center of AGNs, for a specific range of magnetic field magnitudes, since it is possible that ultra-high center-of-mass energies can be produced by particles colliding near the horizon of rotating BHs whose angular momentum tends to the Thorne limit.

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Ultrahigh-energy cosmic ray composition from the distribution of arrival directions

Rita C. dos Anjos, Jorge F. Soriano, Luis A. Anchordoqui et. al. Phys. Rev. D 98, 123018, 2018

Here, we run a full-blown simulation study to accurately characterize the deflections of UHECR nuclei in the GMF. We show that while the cepa stratis structure provides a global description of anisotropy patterns produced by UHECR nuclei en route to Earth, the hot spots are elongated depending on their location in the sky due to the regular structure of the GMF. We demonstrate that with a high-statistics sample at the high-energy end of the spectrum, like the one to be collected by NASA’s Probe Of Extreme Multi-Messenger Astrophysics mission, the energy dependence of the hot spot contours could become a useful observable to identify the nuclear composition of UHECRs.

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The influence of the observatory latitude on the study of UHECRs

R. C. Anjos, V. de Souza, Rogerio M. de Almeida and Edivaldo M. Santos. JCAP, Vol:2017, 1475, 2017

In this paper, distributions of arrival directions of events in the nearby Universe are assumed to correlate with sources in the 2MASS Redshift Survey (2MRS), IRAS 1.2 Jy Survey, Palermo Swift-BAT and Swift-BAT catalogs, and the effect of the latitude of the observatory on the measurement of the energy spectrum and on the capability of measuring anisotropy is studied. The differences between given latitudes on the northern and southern hemispheres are quantified. It is shown that the latitude of the observatory: a) has an influence on the total flux measured and b) imposes an important limitation on the capability of measuring an anisotropic sky.

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Central accumulation of magnetic flux in massive Seyfert galaxies as a possible engine to trigger UHECRs

R. C. Anjos and C. H. Coimbra-Araújo. Phys. Rev. D 96, 023008, 2017.

In the present paper we investigate the production of ultrahigh energy cosmic rays (UHECRs) from Seyferts. We discuss the UHECR luminosities obtained by two possible engine trigger models: pure radiative transfer and the energy extraction from poloidal magnetic flux. The first case is modeled by Kerr slim disk or Bondi accretion mechanisms. Since it is assumed that the broadband spectra of Seyferts indicate that at least the outer portions of their accretion disks are cold and geometrically thin, and since our results point that the consequent radiative energy transfer is inefficient, we build the second approach based on massive Seyferts with sufficient central poloidal magnetic field to trigger an outflow of magnetically driven charged particles capable to explain the observed UHECRs and gamma rays in Earth experiments from a given Seyfert source.

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Academic.

 

 

 

Contact.

ritacassia@ufpr.br skype: rita.anjos7 55-44-3211-8575
  • R. Pioneiro, 2153 - Dallas, Palotina - PR, 85950-000
  • Building III, Room1
  • Engineering and Exact Sciences Departament,
  • Federal University of Paraná - Sector Palotina