91 |
Outflow and Accretion Physics in Active Galactic NucleiMcGraw, Sean Michael 21 September 2016 (has links)
No description available.
|
92 |
Measurement of the energy spectrum of the BL Lac object PG1553+113 with the MAGIC telescope in 2005 and 2006Hengstebeck, Thomas 01 June 2007 (has links)
In dieser Doktorarbeit wurden im Rahmen des MAGIC Experimentes neue Datenanalysemethoden implementiert, die sich insbesondere fuer die Analyse von Ereignissen niedriger Gammastrahlungsenergie eignen. Die Methoden konnten erfolgreich in Monte Carlo Studien getestet und auf Beobachtungsdaten des Krebsnebels und der extragalaktischen Gammastrahlungsquelle PG1553+113 angewandt werden. Diese Methoden reichen von ''image cleaning'' Techniken und der Nutzung neuer Bildparameter bis zu fortgeschrittenen g/h-Separations- und Energieabschaetzungsverfahren. Zum ersten Mal wurden die Vorteile von Klassifikations- und Regressionsbaeumen in der Gamma-Astrophysik ausgenutzt, um existierende klassische Methoden zu verbessern. Die Analyse - getestet an Monte Carlo Daten - bewies ihre Zuverlaessigkeit bei der Untersuchung der Gammastrahlungsemission des Krebsnebels, wobei ein hochsignifikanter Exzess im Energiebereich unterhalb 100 GeV in nur 1.7 h nachgewiesen werden konnte. Die Analyse von Daten des BL Lac Objekts PG1553+113 ergab signifikante Exzesse fuer Beobachtungen in den Jahren 2005 und 2006. Das kombinierte alpha-Histogramm zeigt ein Signal mit einer Signifikanz, die 8 sigma ueberschreitet. Bei der weiteren Analyse konnte ein differentielles Energiespektrum fuer die kombinierten Daten aus den Jahren 2005 und 2006 erstellt werden. Der integrale Fluss oberhalb von 200 GeV wurde wie folgt bestimmt: F(> 200 GeV) = (1.7+-0.3) 10^(-12)/(cm^2 s), der spektrale Index betraegt Gamma = 3.6+-0.3. Dieses Spektrum konnte daraufhin verwendet werden, um die (unbekannte) Rotverschiebung von PG1553+113 auf z / In this thesis new data analysis methods for the MAGIC experiment were implemented, which are especially suited for the investigation of low energy gamma-ray events. They were successfully tested by means of Monte Carlo studies and applied to observational data of the Crab Nebula and of the extragalactic gamma-ray source PG1553+113. These methods extend from image cleaning techniques and the utilization of new image parameters to sophisticated g/h-separation and energy estimation approaches. For the first time in gamma-ray astrophysics the advantages of classification and regression trees were exploited in order to improve existing `classical'' methods. The analysis procedure - tested on Monte Carlo data - was demonstrated to be reliable in the investigation of the Crab Nebula gamma-ray emission yielding a significant excess in the energy range below 100 GeV in only 1.7 h observation time. The analysis of data taken on the BL Lac PG1553+113 yielded significant excesses for both years 2005 and 2006. The combined alpha histogram shows a signal in excess of 8 sigma. In the further analysis a spectrum could be derived for the combined data sets of 2005 and 2006. The integral flux above 200 GeV could be derived as F(> 200 GeV) = (1.7+-0.3) 10^(-12)/(cm^2 s), the power-law index was measured to be Gamma = 3.6+-0.3. This spectrum was used to constrain the redshift z of PG1553+113 with the result z
|
93 |
Role of AGN feedback in galaxy evolution at high-redshift / Rôle de la rétroaction des noyaux actifs de galaxie dans l'évolution des galaxies à haut décalage spectral vers le rougeCollet, Cédric 28 April 2014 (has links)
Il y a de plus en plus d'indications que les trous noirs super-massifs ont joué un rôle important dans l'évolution des galaxies, en particulier au moment de la formation des galaxies les plus massives à haut décalage spectral vers le rouge (z ~ 2 - 3). Nous nous sommes attachés à quantifier les effets sur le milieu interstellaire des galaxies hôtes que peuvent avoir les jets des radio-galaxies, d'une part, et les importantes luminosités bolometriques des quasars, d'autre part. Pour cela, nous avons étudié la cinématique du gaz ionisé dans 12 radio-galaxies modérément puissantes et dans 11 quasars (6 avec une détection en radio et 5 sans jet détectable) à grand décalage spectral vers le rouge avec le spectro-imageur proche infra-rouge SINFONI du VLT, qui nous donnait accès aux raies d'émission normalement sitées dans le domaine visible. Afin d'évaluer la capacité du NAG à stopper la formation d'étoiles, nous avons cherché des traces de leur rétroaction dans ces galaxies, comme de vents de gaz s'échappant de la galaxie hôte. Dans notre échantillon de radio-galaxies modérément puissantes, nous observons des dispersions de vitesse presque aussi importantes que dans les plus puissantes (avec une FWHM ~ 1000 km/s), mais les quantités de gaz ionisé observées y sont inférieures d'un ordre de grandeur (Mion gas ~ 10^8 - 10^9 Msun) et les gradients de vitesse sont plus faibles (Δv < 400 km/s), quand ils sont observés. Dans notre échantillon de quasars, nous devions d'abord soustraire la composante large des raies d'émission avant de pouvoir étudier leur composante étroite, celle susceptible d'être étendue spatialement. Nous détectons des régions d'émission véritablement étendue autour de quatre des six sources avec une détection en radio et autour d'une seule des cinq sans détection radio. Nous estimons qu'il y a moins de gaz ionisé dans ces sources que dans notre échantillon de radio-galaxies (avec Mion gas ~ 10^7 - 10^8 Msun) et la cinématique de ce gaz est aussi plus calme, similaire à ce qui est observé autour de certains quasars proches. Enfin, de nouvelles observations de deux radio-galaxies particulières nous ont révélé que l'une d'entre elles est entourée de quatorze galaxies-companions et qu'elle se trouve donc dans une partie sur-dense de l'Univers. Nous expliquons donc la morphologie inhabituelle du gaz ionisé présent autour de ces deux radio-galaxies par des cycles répétés d'activité du NAG, en analogie à ce qui est observé dans les amas de galaxies proches, qui sont d'excellents exemples de rétroaction du NAG dans l'Univers local. / There is growing evidence that supermassive black holes may play a crucial role for galaxy evolution, in particular during the formation of massive galaxies at high redshift (z ~ 2 - 3). Our work focuses on quantifying the effects of jets of radiogalaxies and of large bolometric luminosities of quasars on the interstellar gas in their host galaxies. To this end, we studied the kinematics of the ionized gas in 12 moderately powerful radio galaxies and 11 quasars (6 radio-loud and 5 radio-quiet) at high redshifts with rest-frame optical imaging spectroscopy obtained at the VLT with SINFONI. We searched for outflows and other signatures of feedback from the supermassive black holes in the centers of these galaxies to evaluate if the AGN may plausibly quench star formation. In our sample of moderately powerful radiogalaxies, we observe velocity dispersions nearly as large as those observed in the most powerful ones (with FWHM ~ 1000 km/s), but the quantity of ionized gas is decreased by one order of magnitude (Mion gas ~ 10^8 - 10^9 Msun) and velocity gradients tend to be less dramatic (Δv < 400 km/s), when they are observed. In our sample of quasars, we had to carefully subtract the broad spectral component of emission lines to have access to its narrow, and spatially extended, component. We detect truly extended emission line regions in 4/6 sources of our radio-loud subsample and in 1/5 source of our radio-quiet subsample. We estimate that masses of ionized gas in these sources are smaller than in our sample of high-redshift radiogalaxies (with Mion gas ~ 10^7 - 10^8 Msun) and kinematics tend to be more quiescent, akin to what is observed in local quasars. Finally, detailed observations of two outliers among our sample of high-redshift radiogalaxies revealed that one of them is closely surrounded by 14 companions galaxies, hence lying in an overdensity. We therefore interpret the presence and morphology of ionized gas around these galaxies as evidence for repeated cycles ouf AGN outbursts, akin to what can be observed in local clusters of galaxies, which are prime examples of AGN feedback in the nearby Universe.
|
94 |
Study of Persistent and Flaring Gamma-Ray Emission from Active Galactic Nuclei with the MAGIC Telescopes and Prospects for Future Open Data Formats in Gamma-Ray AstronomyNigro, Cosimo 17 October 2019 (has links)
Angetrieben durch die Akkretion von Materie in ein super massives Schwarzes Loch in ihrem Zentrum, stellen aktive Galaxien die stärksten und beständigsten Strahlungsquellen im Universum dar. Ihre elektromagnetische Emission kann sich bis in den Gammastrahlenbereich ausbreiten. Das Ziel dieser Arbeit ist, diese Mechanismen und die Orte jenseits der hoch energetischen Emission zu charakterisieren. Dafür werden die Observationen von zwei Aktiven Galaxien im Bereich von hunderten von GeV verwendet, welche mit den Cherenkov Teleskopen MAGIC aufgenommen wurden. Die physikalische Interpretation wird durch Beobachtungen mit dem Fermi Gamma-ray Space Teleskop und durch Multiwellenlängendaten unterstützt. Es werden zwei Aktive Galaxien mit Jet untersucht: PKS 1510-089 und NGC 1275. Die MAGIC Teleskope, welche PKS 1510-089 seit 2012 immer wieder beobachten, detektieren eine signifikante Emission über dutzende von Observationsstunden, was auf schwache aber kontinuierliche Gammastrahlung aus dieser Quelle hinweist. NGC 1275 zeigte in der Periode von September 2016 bis Februar 2017 einen großen Ausbruch im Gammerstrahlenbereich: MAGIC zeichnete eine Variabilität in der Größenordnung von wenigen Stunden und die erstmalige Emission von TeV Photonen. Aus beiden untersuchten Quellen ist ersichtlich, dass die Kombination von Daten aus verschiedenen Instrumenten die physische Diskussion entscheidend beeinflusst. Der Übergang zu zugänglichen und interoperablen Daten wird zu einem zwingenden Thema für Gammastrahlenastronomen, und diese Arbeit stellt das technische Bestreben dar, standardisierte hochrangige Daten für Gammastrahleninstrumente zu erzeugen. Ein Beispiel für eine zukünftige Analyse, die einheitliche High-Level-Daten von einem Gammastrahlensatelliten und vier Cherenkov-Teleskopen kombiniert, wird vorgestellt. Der neue Ansatz, der vorgeschlagen wird, führt die Datenanalyse durch und verbreitet die Ergebnisse, wobei nur Open-Source-Ressourcen verwendet werden. / Powered by the accretion of matter to a supermassive black hole, active galactic nuclei constitute the most powerful and persistent sources of radiation in the universe, with emission extending in the gamma-ray domain. The aim of this work is to characterise the mechanisms and sites beyond this highly-energetic radiation employing observations of two galaxies at hundreds of GeV, conducted with the MAGIC imaging Cherenkov telescopes. The physical interpretation is supported with observations by the Fermi Gamma-ray Space Telescope and with multi-wavelength data. Two peculiar jetted galaxies are studied: PKS 1510-089 and NGC 1275. The first source, monitored by MAGIC since 2012, presents a significant emission over tens of observation hours, in what appears to be a low but persistent gamma-ray state. The second source has instead shown, in the period between September 2016 and February 2017, a major outburst in its gamma-ray activity with variability of the order of few hours and emission of TeV photons. The broad band emission of jetted galaxies is commonly modelled with the radiative processes of a population of electrons accelerated in the jet. While PKS 1510-089 conforms to this scenario, modelling the gamma-ray outburst of NGC 1275 requires placing the acceleration and radiation of electrons close to the event horizon of the black hole. From both the sources studied it is evident that the combination of data from different instruments critically drives the physical discussuion. Moving towards accessible and interoperable data becomes a compelling issue for gamma-ray astronomers and this thesis presents the technical endeavour to produce standardised high-level data for gamma-ray instruments. An example of a future analysis combining uniformed high-level data from a gamma-ray satellite and four Cherenkov telescopes is presented. The novel approach proposed performs the data analysis and disseminates the results making use only of open-source assets.
|
95 |
A responsabilidade do juiz da execu??o penal na expans?o do poder punitivo : uma an?lise a partir da correla??o entre os fatores sociol?gicos que explicam as diverg?ncias entre o discurso do direito e da psicologia quanto ? exig?ncia de exame criminol?gico para progress?o de regime e os modelos dogm?ticos de justifica??o da penaLamare, Bruno Jacoby de 08 December 2017 (has links)
Submitted by PPG Ci?ncias Criminais (ppgccrim@pucrs.br) on 2018-04-18T20:46:15Z
No. of bitstreams: 1
BRUNO DELAMARE - vers?o definitiva_corre??es p?s banca.pdf: 1796892 bytes, checksum: 02b9c05674cdc41dfd77761f2f69737a (MD5) / Approved for entry into archive by Caroline Xavier (caroline.xavier@pucrs.br) on 2018-05-07T13:05:59Z (GMT) No. of bitstreams: 1
BRUNO DELAMARE - vers?o definitiva_corre??es p?s banca.pdf: 1796892 bytes, checksum: 02b9c05674cdc41dfd77761f2f69737a (MD5) / Made available in DSpace on 2018-05-07T13:06:45Z (GMT). No. of bitstreams: 1
BRUNO DELAMARE - vers?o definitiva_corre??es p?s banca.pdf: 1796892 bytes, checksum: 02b9c05674cdc41dfd77761f2f69737a (MD5)
Previous issue date: 2017-12-08 / Dos creencias que gravitan en torno al examen criminol?gico tambi?n caracterizan el cuadro de expansi?n del poder punitivo en la actualidad: (a) en las finalidades positivas que se atribuyen a la pena, representada por la creencia de que la experiencia en la c?rcel podr?a transformar positivamente el comportamiento del apenado; (b) y en la autosuficiencia del discurso jur?dico, representada por la creencia de que el examen criminol?gico realizado por psic?logo puede pronosticar la perspectiva de reinserci?n social del apenado, aun cuando el discurso cr?tico oriundo de la Psicolog?a no visualiza esta potencialidad. De la concatenaci?n entre estas dos creencias es que surgi? la principal hip?tesis que fundamento el problema de la presente investigaci?n: los factores sociol?gicos que explican la resistencia del discurso jur?dico a la aceptaci?n del discurso cr?tico que le es externo est?n relacionados a los fundamentos que caracterizan a los modelos dogm?ticos que atribuyen finalidades positivas a la pena, influenciando ambos el papel que desempe?an los operadores jur?dicos en la expansi?n del poder punitivo. El abordaje del problema se realiz? a partir de cuatro pilares te?ricos, considerados a partir de sus interrelaciones: (a) los modelos dogm?ticos de justificaci?n positiva de la pena y la concepci?n agn?stica; (b) las divergencias entre los discursos del Derecho y de la Psicolog?a en cuanto a la potencialidad pron?stica del examen criminol?gico; (c) los factores sociol?gicos que explican la resistencia del discurso jur?dico a la aceptaci?n del discurso cr?tico que le es externo y (d) la influencia de la relaci?n existente entre aquellos factores sociol?gicos y aquellos modelos dogm?ticos en la g?nesis de la conducta de los magistrados que exigen el examen criminol?gico para los fines de progresi?n del r?gimen. Se aplic? tambi?n cuestionario, por medio del cual magistrados y psic?logos que operan con ejecuci?n de la pena privativa de libertad en el Estado del Rio Grande Sul fueron indagados acerca de su respectiva posici?n en cuanto al problema, los motivos que la justifican y el nivel de receptividad al discurso externo a su respectivo campo de origen. As?, a partir de la correlaci?n entre esos pilares te?ricos y los resultados del cuestionario, se prob? la adecuaci?n de la hip?tesis, evalu?ndose si las razones invocadas por los jueces para justificar su posici?n correspond?an a los fundamentos que la doctrina especializada atribuye a los modelos dogm?ticos de justificaci?n de la pena y de la postura que visualiza como propia de los magistrados que operan como agentes de legitimaci?n de la expansi?n del poder punitivo. / Duas cren?as que gravitam em torno do exame criminol?gico tamb?m caracterizam o quadro de expans?o do poder punitivo na atualidade: (a) nas finalidades positivas que s?o atribu?das ? pena, representada pela cren?a de que a experi?ncia no c?rcere poderia transformar positivamente o comportamento do apenado; (b) e na autossufici?ncia do discurso jur?dico, representada pela cren?a de que o exame criminol?gico realizado por psic?logo pode prognosticar a perspectiva de reinser??o social do apenado, mesmo quando o discurso cr?tico oriundo da Psicologia n?o visualiza essa potencialidade. Da concatena??o entre essas duas cren?as ? que surgiu a principal hip?tese que fundamentou o problema da presente pesquisa: os fatores sociol?gicos que explicam a resist?ncia do discurso jur?dico ? aceita??o do discurso cr?tico que lhe ? externo est?o relacionados aos fundamentos que caracterizam os modelos dogm?ticos que atribuem finalidades positivas ? pena, influenciando ambos o papel que ? desempenhado pelos operadores jur?dicos na expans?o do poder punitivo. Este problema foi abordado a partir de quatro pilares te?ricos, considerados a partir de suas inter-rela??es: (a) os modelos dogm?ticos de justifica??o positiva da pena e a concep??o agn?stica; (b) as diverg?ncias entre os discursos do Direito e da Psicologia quanto ? potencialidade progn?stica do exame criminol?gico; (c) os fatores sociol?gicos que explicam a resist?ncia do discurso jur?dico ? aceita??o do discurso cr?tico que lhe ? externo; e (d) a influ?ncia da rela??o existente entre aqueles fatores sociol?gicos e aqueles modelos dogm?ticos na g?nese da conduta dos magistrados que exigem o exame criminol?gico para fins de progress?o de regime. Foi aplicado, ainda, question?rio, por meio do qual magistrados e psic?logos que operam com execu??o da pena privativa de liberdade no Estado do Rio Grande Sul foram indagados acerca da sua respectiva posi??o quanto ao problema, os motivos que a justificam e o n?vel de receptividade ao discurso externo ao seu respectivo campo de origem. Assim, a partir da correla??o entre aqueles pilares te?ricos e os resultados do question?rio, testou-se a adequa??o da hip?tese, aferindo-se se as raz?es invocadas pelos ju?zes para justificar sua posi??o correspondiam aos fundamentos que a doutrina especializada atribui aos modelos dogm?ticos de justifica??o positiva da pena e ? postura que visualiza como pr?pria dos magistrados que operam como agentes de legitima??o da expans?o do poder punitivo.
|
96 |
Utilizando algoritmo de cross-entropy para a modelagem de imagens de núcleos ativos de galáxias obtidas com o VLBAPerianhes, Roberto Vitoriano 09 August 2017 (has links)
Submitted by Marta Toyoda (1144061@mackenzie.br) on 2018-02-16T23:06:29Z
No. of bitstreams: 2
Roberto Vitoriano Perianhes.pdf: 5483045 bytes, checksum: 54cb8ad49fe9a8dd9da3aaabb8076b2f (MD5)
license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Paola Damato (repositorio@mackenzie.br) on 2018-03-08T11:19:18Z (GMT) No. of bitstreams: 2
Roberto Vitoriano Perianhes.pdf: 5483045 bytes, checksum: 54cb8ad49fe9a8dd9da3aaabb8076b2f (MD5)
license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-03-08T11:19:18Z (GMT). No. of bitstreams: 2
Roberto Vitoriano Perianhes.pdf: 5483045 bytes, checksum: 54cb8ad49fe9a8dd9da3aaabb8076b2f (MD5)
license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)
Previous issue date: 2017-08-09 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The images obtained by interferometers such as VLBA (Very Long Baseline Array) and VLBI (Very Long Baseline Interferometry), remain the direct evidence of relativistic jets and outbursts associated with supermassive black holes in active galactic nuclei (AGN). The study of these images are critical tools to the use of information from these observations, since they are one of the main ingredients for synthesis codes7 of extragalactic objects. In this thesis is used both synthetic and observed images. The VLBA images show 2-dimensional observations generated from complex 3-dimensional astrophysical processes. In this sense, one of the main difficulties of the models is the definition of parameters of functions and equations to reproduce macroscopic and dynamic physical formation events of these objects, so that images could be study reliably and on a large scale. One of the goals of this thesis is to elaborate a generic8 form of observations, assuming that the formation of these objects had origin directly by similar astrophysical processes, given the information of certain parameters of the formation events. The definition of parameters that reproduce the observations are key to the generalization formation of sources and extragalactic jets. Most observation articles have focus on few or even unique objects. The purpose of this project is to implement an innovative method, more robust and efficient, for modeling and rendering projects of various objects, such as the MOJAVE Project, which monitors several quasars simultaneously offering a diverse library for creating models (Quasars9 and Blazars10: OVV11 and BL Lacertae12). In this thesis was implemented a dynamic way to study these objects. Presents in this thesis the adaptation of the Cross-Entropy algorithm for the calibration of the parameters of astrophysical events that summarize the actual events of the VLBA observations. The development of the code of the adaptation structure includes the possibility of extension to any image, assuming that these images are dispose in intensities (Jy/beam) distributed in Right Ascension (AR) and Declination (DEC) maps. The code is validating by searching for self-convergence to synthetic models with the same structure, i.e, realistics simulations of components ejection, in milliarcsecond, similar to the observations of the MOJAVE project in 15.3 GHz. With the use of the parameters major semi-axis, angle of position, eccentricity and intensity applied individually to each observed component, it was possible to calculate the structure of the sources, the velocities of the jets, as well as the conversion in flux density to obtain light curves. Through the light curve, the brightness temperature, the Doppler factor, the Lorentz factor and the observation angle of the extragalactic objects can be estimated with precision. The objects OJ 287, 4C +15.05, 3C 279 and 4C +29.45 are studied in this thesis due the fact that they have different and complex morphologies for a more complete study. / As imagens obtidas por interferômetros, tais como VLBA (Very Long Baseline Array) e VLBI (Very Long Baseline Interferometry), são evidências diretas de jatos relativísticos associados a buracos negros supermassivos em núcleos ativos de galáxias (AGN). O estudo dessas imagens é fundamental para o aproveitamento das informações dessas observações, já que é um dos principais ingredientes para os códigos de síntese1 de objetos extragalácticos. Utiliza-se nesta tese, tanto imagens sintéticas quanto observadas. As imagens de VLBA mostram observações em 2 dimensões de processos astrofísicos complexos ocorrendo em 3 dimensões. Nesse sentido, uma das principais dificuldades dos modelos é a definição dos parâmetros das funções e equações que reproduzam de forma macroscópica e dinâmica os eventos físicos de formação desses objetos, para que as imagens sejam estudadas de forma confiável e em grande escala. Um dos objetivos desta tese é elaborar uma forma genérica2 de observações, supondo que a formação desses objetos é originada por processos astrofísicos similares, com a informação de determinados parâmetros da formação dos eventos. A definição de parâmetros que reproduzam as observações são elementos chave para a generalização da formação de componentes em jatos extragalácticos. Grande parte dos artigos de observação são voltados para poucos ou únicos objetos. Foi realizada nesta tese a implementação um método inovador, robusto e eficiente para a modelagem e reprodução de vários objetos, como por exemplo nas fontes do Projeto MOJAVE, que monitora diversos quasares simultaneamente, oferecendo uma biblioteca diversificada para a criação de modelos (Quasares3 e Blazares4: OVV5 e BL Lacertae6). Com essas fontes implementou-se uma forma dinâmica para o estudo desses objetos. Apresenta-se, nesta tese, a adaptação do algoritmo de Cross-Entropy para a calibração dos parâmetros dos eventos astrofísicos que sintetizem os eventos reais das observações em VLBA. O desenvolvimento da estrutura de adaptação do código incluiu a possibilidade de extensão para qualquer imagem, supondo que as mesmas estão dispostas em intensidades (Jy/beam) distribuídas em mapas de Ascensão Reta (AR) e Declinação (DEC). A validação do código foi feita buscando a auto convergência para modelos sintéticos com as mesmas estruturas, ou seja, de simulações realísticas de ejeção de componentes, em milissegundos de arco, similares às observações do projeto MOJAVE, em 15,3 GHz. Com a utilização dos parâmetros semieixo maior, ângulo de posição, excentricidade e intensidade aplicados individualmente a cada componente observada, é possível calcular a estrutura das fontes, as velocidades dos jatos, bem como a conversão em densidade de fluxo para obtenção de curvas de luz. Através da curva de luz estimou-se com precisão a temperatura de brilhância, o fator Doppler, o fator de Lorentz e o ângulo de observação dos objetos extragalácticos. Os objetos OJ 287, 4C +15.05, 3C 279 e 4C +29.45 são estudados nesta tese pois têm morfologias diferentes e complexas para um estudo mais completo.
|
97 |
Role of AGN feedback in galaxy evolution at high-redshiftCollet, Cédric 28 April 2014 (has links) (PDF)
There is growing evidence that supermassive black holes may play a crucial role for galaxy evolution, in particular during the formation of massive galaxies at high redshift (z ~ 2 - 3). Our work focuses on quantifying the effects of jets of radiogalaxies and of large bolometric luminosities of quasars on the interstellar gas in their host galaxies. To this end, we studied the kinematics of the ionized gas in 12 moderately powerful radio galaxies and 11 quasars (6 radio-loud and 5 radio-quiet) at high redshifts with rest-frame optical imaging spectroscopy obtained at the VLT with SINFONI. We searched for outflows and other signatures of feedback from the supermassive black holes in the centers of these galaxies to evaluate if the AGN may plausibly quench star formation. In our sample of moderately powerful radiogalaxies, we observe velocity dispersions nearly as large as those observed in the most powerful ones (with FWHM ~ 1000 km/s), but the quantity of ionized gas is decreased by one order of magnitude (Mion gas ~ 10^8 - 10^9 Msun) and velocity gradients tend to be less dramatic (Δv < 400 km/s), when they are observed. In our sample of quasars, we had to carefully subtract the broad spectral component of emission lines to have access to its narrow, and spatially extended, component. We detect truly extended emission line regions in 4/6 sources of our radio-loud subsample and in 1/5 source of our radio-quiet subsample. We estimate that masses of ionized gas in these sources are smaller than in our sample of high-redshift radiogalaxies (with Mion gas ~ 10^7 - 10^8 Msun) and kinematics tend to be more quiescent, akin to what is observed in local quasars. Finally, detailed observations of two outliers among our sample of high-redshift radiogalaxies revealed that one of them is closely surrounded by 14 companions galaxies, hence lying in an overdensity. We therefore interpret the presence and morphology of ionized gas around these galaxies as evidence for repeated cycles ouf AGN outbursts, akin to what can be observed in local clusters of galaxies, which are prime examples of AGN feedback in the nearby Universe.
|
Page generated in 0.0544 seconds