Exploring the environment of high Rotation Measure Active Galactic Nuclei through wide-band radio spectropolarimetry observations

In this Thesis I present an observational study of a sample of radio AGN sources. I study their radio polarization properties in a wide frequency range by observing with the 100-m Effelsberg telescope and the Very Large Array (VLA) interferometer. The aim was 1) to define a sample of candidates to contain an extreme environment around the SMBH and, 2) to study their environment by modeling of the polarization properties within a wide frequency range. I select sources with no detectable flux polarization at 1.4GHz in the NVSS survey, characteristic of strong depolarization due to a high value of Rotation Measure (RM) and thus, of an extreme medium in these sources. I performed single dish observations at 10.45 GHz using the 100-m Effelsberg telescope. At this high frequency, I detected polarized flux density on 30 sources, which became our high-RM candidates. Single dish follow-up in the 2 to 15 GHz frequency range, were performed to characterize their radio spectra and to determine their RMs. The polarization angle behavior deviates significantly from the lambda^2 law, suggesting that several Faraday screens are present in the intervening medium. I studied the most interesting high-RM cases through wide-band high sensitive observations at C and X bands using the JVLA. I modeled the polarization properties constructing a set of models which are combinations of simple internal and the external Faraday screens. This new approach of polarization study allows to spectrally resolve multiple polarized components of unresolved AGN with the result to trace some clumpy and dense region surrounding them. This new spectropolarimetry approach can be adopted as a new way to trace clumpy and dense regions surrounding the AGN

Probing the Large Faraday Rotation Measure Environment of Compact Active Galactic Nuclei

Knowing how the ambient medium in the vicinity of active galactic nuclei (AGNs) is shaped is crucial to understanding generally the evolution of such cosmic giants as well as AGN jet formation and launching. Thanks to the new broadband capability now available at the Jansky Very Large Array (JVLA), we can study changes in polarization properties, fractional polarization, and polarization angles, together with the total intensity spectra of a sample of 14 AGNs, within a frequency range from 1 to 12 GHz. Depolarization modeling has been performed by means of so-called "qu-fitting" to the polarized data, and a synchrotron self absorption model has been used for fitting to the total intensity data. We found complex behavior both in the polarization spectra and in the total intensity spectra, and several Faraday components with a large rotation measure (RM) and several synchrotron components were needed to represent these spectra. Here, results for three targets are shown. This new method of analyzing broadband polarization data through qu-fitting successfully maps the complex surroundings of unresolved objects

Estilo de vida de praticantes de corrida de rua

Introduction: Street racing has gained more fans and admirers every day, this being a sport that became popular in the middle of the 19th century and. which brings countless benefits to the body, such as protection against various diseases. Regardless of the sport, nutritional behaviors are crucial for maintaining health, increasing athletic performance and controlling athletes' body composition. Objective: To evaluate the lifestyle of street runners from different regions of Brazil. Materials and methods: This is a cross-sectional study, carried out with amateur street racers, adults, of both sexes, living in different regions of Brazil. Data collection was performed using a questionnaire available on the Google Forms® platform that contained information about. feeding habits, smoking, consumption of alcohol and other substances, hydration, sleep duration and motivations for running.Results: 106 runners were evaluated, with an average age of 36 years, who practiced running mainly for the purpose of weight loss and mental health.. Participants showed improvements in humor, breathing, depression symptoms, feeling of freedom and creativity after starting to practice running. it was observed that 31.8% of respondents improved their feeding habits since they started running. Conclusion: This article demonstrated the positive impact that running has on quality of life and on the professional follow-up index of nutritionists.Introdução: As corridas de rua têm ganhado mais adeptos e admiradores a cada dia, sendo esta uma modalidade esportiva que se popularizou em meados do século 19 e   que traz inúmeros benefícios ao organismo, como a proteção contra diversas doenças. Independente da modalidade esportiva, as condutas nutricionais são determinantes na manutenção da saúde, no aumento do desempenho atlético e no controle da composição corporal de atletas. Objetivo: Avaliar hábitos de vida de praticantes de corrida de rua de diferentes regiões do Brasil. Materiais e métodos: Trata-se de um estudo transversal, realizado com corredores de rua amadores, adultos, de ambos os sexos, residentes em diferentes regiões do Brasil. A coleta de dados foi efetuada a partir de um questionário disponibilizado na plataforma Google Forms® que continha informações sobre hábitos alimentares tabagismo, etilismo e uso de outras substâncias psicoativas; hidratação; duração do sono e motivações para a prática de corrida.  Resultados: Foram avaliados 106 corredores, com idade média de 36 anos, que praticavam a corrida principalmente com o objetivo de emagrecimento e saúde mental. Os participantes relataram melhora de humor, respiração, melhora nos sintomas de depressão, sensação de liberdade, melhora na libido e na criatividade após iniciarem o hábito do exercício. Observou-se que 31,8% dos entrevistados melhoraram sua alimentação desde que iniciaram a prática da corrida. Conclusão: O presente artigo demonstrou o impacto positivo que a corrida exerce sobre a qualidade de vida e saúde dos participantes, ressaltando a importância da modalidade

Message in a Bottle: Unveiling the Magneto-Ionic Complexity of AGNs through the Stokes QU-Fitting Technique

Here, I overview one of the available techniques for the analysis of broad-band spectropolarimetric data, the Stokes QU-fitting. Since broad-band receivers have been installed at most radio facilities, the collection of radio data, both the total intensity and the linear polarization, is revealing interesting features in their spectra. The polarized light, and therefore its properties, i.e. the fractional polarization p and the polarized angle χ, are now finally well sampled in wide wavelength ranges. The new complex behaviors revealed by the data can be studied using the Stokes QU-fitting, which consists of modeling the Stokes parameters Q and U using wavelength-dependent analytical models, available in the literature. This technique provides a very good diagnostic of the nature and structure of the magnetized plasma, with the possibility to identify complex structures, internal or external, of the source of study. A summary of the available and most used models describing the polarization behavior, is presented. Moreover, some of the most significant observational works which use this technique are also summarized

JVLA Wideband Polarimetry Observations on a Sample of High Rotation Measure Sources

We present preliminary results of JVLA wideband full polarization observations of a sample of Active Galactic Nuclei (AGN) with very high Rotation Measure (RM) values, a sign of extreme environment. Polarization properties show a complex behaviour such that the polarization angle (PA) and fractional polarization (fp) change dramatically within the wide band. The measured RM is not constant within the wide band. Its complex behaviour reflects the complexity of the medium with the presence of several Faraday components. The depolarization has been studied by modelling the variations of the Stokes parameters Q and U together with the polarization parameters (PA and fp) with wavelength using combinations of the simplest existing depolarization models. With this JVLA study we could spectrally resolve multiple polarized components of unresolved AGN. These preliminary results reveal the complexity of these objects, but improvements to the depolarization modelling are needed to better understand the polarization structure of these sources

Probing the Large Faraday Rotation Measure Environment of Compact Active Galactic Nuclei

Knowing how the ambient medium in the vicinity of active galactic nuclei (AGNs) is shaped is crucial to understanding generally the evolution of such cosmic giants as well as AGN jet formation and launching. Thanks to the new broadband capability now available at the Jansky Very Large Array (JVLA), we can study changes in polarization properties, fractional polarization, and polarization angles, together with the total intensity spectra of a sample of 14 AGNs, within a frequency range from 1 to 12 GHz. Depolarization modeling has been performed by means of so-called “qu-fitting” to the polarized data, and a synchrotron self absorption model has been used for fitting to the total intensity data. We found complex behavior both in the polarization spectra and in the total intensity spectra, and several Faraday components with a large rotation measure (RM) and several synchrotron components were needed to represent these spectra. Here, results for three targets are shown. This new method of analyzing broadband polarization data through qu-fitting successfully maps the complex surroundings of unresolved objects