Nesse trabalho, foi feito o tratamento e a análise de cubos de dados de 8 núcleos ativos de galáxias próximos, no óptico e no infravermelho. O tratamento e a análise de todos os cubos de dados foram feitos utilizando-se uma série de metodologias específicas, muitas das quais foram desenvolvidas nos últimos anos pelo grupo de trabalho do autor. A análise de todos os cubos de dados foi feita com quatro objetivos principais: análise da fenomenologia geral nos arredores do AGN com a Tomografia PCA; análise das populações estelares, da emissão térmica de poeira e do featureless continuum nos arredores do AGN com uma síntese espectral feita com o software Starlight; análise da cinemática estelar e do gás ao redor do buraco negro central e, em alguns casos, simulação com o objetivo de se determinar a massa do buraco negro; análise dos mecanismos de excitação e ionização do gás ou da emissão de hidrogênio molecular. / In this work, we have treated and analyzed data cubes of 8 nearby active galactic nuclei, in the optical and in the infrared. All data cube treatment and analysis were performed using a series of specific methodologies, many of which were developed in the last few years by the author\'s working group. The analysis of all data cubes was performed with four main objectives: analysis of the general phenomenology of the AGN environment, using PCA Tomography; analysis of the stellar populations, of the thermal emission from dust and of the featureless continuum in the vicinity of the AGN, with a spectral synthesis performed with the Starlight software; analysis of the stellar and gas kinematics around the central black hole and, in some cases, simulations with the purpose of determining the mass of the black hole; analysis of the excitation and ionization mechanisms of the gas or of the emission from molecular hydrogen.

Supermassive black holes are a fundamental component of the universe in general and of galaxies in particular. Almost every massive galaxy harbours a supermassive black hole (SMBH) in its center. Furthermore, there is a close connection between the growth of the SMBH and the evolution of its host galaxy, manifested in the relationship between the mass of the black hole and various properties of the galaxy's spheroid component, like its stellar velocity dispersion, luminosity or mass. Understanding this relationship and the growth of SMBHs is essential for our picture of galaxy formation and evolution. In this thesis, I make several contributions to improve our knowledge on the census of SMBHs and on the coevolution of black holes and galaxies. The first route I follow on this road is to obtain a complete census of the black hole population and its properties. Here, I focus particularly on active black holes, observable as Active Galactic Nuclei (AGN) or quasars. These are found in large surveys of the sky. In this thesis, I use one of these surveys, the Hamburg/ESO survey (HES), to study the AGN population in the local volume (z~0). The demographics of AGN are traditionally represented by the AGN luminosity function, the distribution function of AGN at a given luminosity. I determined the local (z<0.3) optical luminosity function of so-called type 1 AGN, based on the broad band B_J magnitudes and AGN broad Halpha emission line luminosities, free of contamination from the host galaxy. I combined this result with fainter data from the Sloan Digital Sky Survey (SDSS) and constructed the best current optical AGN luminosity function at z~0. The comparison of the luminosity function with higher redshifts supports the current notion of 'AGN downsizing', i.e. the space density of the most luminous AGN peaks at higher redshifts and the space density of less luminous AGN peaks at lower redshifts. However, the AGN luminosity function does not reveal the full picture of active black hole demographics. This requires knowledge of the physical quantities, foremost the black hole mass and the accretion rate of the black hole, and the respective distribution functions, the active black hole mass function and the Eddington ratio distribution function. I developed a method for an unbiased estimate of these two distribution functions, employing a maximum likelihood technique and fully account for the selection function. I used this method to determine the active black hole mass function and the Eddington ratio distribution function for the local universe from the HES. I found a wide intrinsic distribution of black hole accretion rates and black hole masses. The comparison of the local active black hole mass function with the local total black hole mass function reveals evidence for 'AGN downsizing', in the sense that in the local universe the most massive black holes are in a less active stage then lower mass black holes. The second route I follow is a study of redshift evolution in the black hole-galaxy relations. While theoretical models can in general explain the existence of these relations, their redshift evolution puts strong constraints on these models. Observational studies on the black hole-galaxy relations naturally suffer from selection effects. These can potentially bias the conclusions inferred from the observations, if they are not taken into account. I investigated the issue of selection effects on type 1 AGN samples in detail and discuss various sources of bias, e.g. an AGN luminosity bias, an active fraction bias and an AGN evolution bias. If the selection function of the observational sample and the underlying distribution functions are known, it is possible to correct for this bias. I present a fitting method to obtain an unbiased estimate of the intrinsic black hole-galaxy relations from samples that are affected by selection effects. Third, I try to improve our census of dormant black holes and the determination of their masses. One of the most important techniques to determine the black hole mass in quiescent galaxies is via stellar dynamical modeling. This method employs photometric and kinematic observations of the galaxy and infers the gravitational potential from the stellar orbits. This method can reveal the presence of the black hole and give its mass, if the sphere of the black hole's gravitational influence is spatially resolved. However, usually the presence of a dark matter halo is ignored in the dynamical modeling, potentially causing a bias on the determined black hole mass. I ran dynamical models for a sample of 12 galaxies, including a dark matter halo. For galaxies for which the black hole's sphere of influence is not well resolved, I found that the black hole mass is systematically underestimated when the dark matter halo is ignored, while there is almost no effect for galaxies with well resolved sphere of influence. / Supermassereiche Schwarze Löcher sind ein fundamentaler Bestandteil unseres Universims im Allgemeinen, und von Galaxien im Besonderen. Fast jede massereiche Galaxie beherbergt ein supermassereiches Schwarzes Loch in seinem Zentrum. Außerdem existiert eine enge Beziehung zwischen dem Wachstum des Schwarzen Loches und der Entwicklung seiner umgebenden Galaxie. Diese zeigt sich besonders in der engen Beziehung zwischen der Masse eines Schwarzen Loches und den Eigenschaften der sphäroidalen Komponente der Galaxie, beispielsweise seiner stellaren Geschwindigkeitsdispersion, seiner Leuchtkraft und seiner Masse. Diese Beziehung erklären zu können, sowie das Wachstum von Schwarzen Löchern zu verstehen, liefert einen wichtigen Beitrag zu unserem Bild der Entstehung und Entwicklung von Galaxien. In dieser Arbeit steuere ich verschiedene Beiträge dazu bei unser Verständnis des Vorkommens Schwarzer Löcher und der Beziehung zu ihren Galaxien zu verbessern. Zunächst versuche ich ein vollständiges Bild der Anzahl und Eigenschaften Schwarzer Löcher zu erhalten. Dazu beschränke ich mich auf aktive Schwarze Löcher, wie man sie im Universum als Aktive Galaxienkerne (AGN) in großen Himmelsdurchmusterungen finden kann. Ich benutze eine solche Durchmusterung, das Hamburg/ESO Survey (HES), um die AGN Population im lokalen Universum zu studieren. Dazu habe ich die optische Leuchtkraftfunktion von AGN bestimmt. Diese habe ich mit anderen Ergebnissen leuchtschwächerer AGN kombiniert um die bisher beste AGN Leuchtkraftfunktion im lokalen Universum zu erhalten. Der Vergleich mit Ergebnissen bei höherer kosmischer Rotverschiebung bestätigt unser Bild des sogenannten "AGN downsizing". Dies sagt aus, dass leuchtkräftige AGN bei hoher Rotverschiebung am häufigsten vorkommen, während leuchtschwache AGN bei niedriger Rotverschiebung am häufigsten sind. Allerdings verrät uns die AGN Leuchtkraftfunktion allein noch nicht das ganze Bild der Demographie Schwarzer Löcher. Vielmehr sind wir an den zugrunde liegenden Eigenschaften, vor allem der Masse und der Akkretionsrate der Schwarzen Löcher, sowie deren statistischen Verteilungsfunktionen, interessiert. Ich habe eine Methode entwickelt um diese beiden Verteilungsfunktionen zu bestimmen, basierend auf der Maximum-Likelihood-Methode. Ich habe diese Methode benutzt um die aktive Massenfunktion Schwarzer Löcher, sowie die Verteilungsfunktion ihrer Akkretionsraten für das lokale Universum aus dem HES zu bestimmen. Sowohl die Akkretionsraten, als auch die Massen der Schwarzen Löcher zeigen intrinsisch eine breite Verteilung, im Gegensatz zur schmaleren beobachtbaren Verteilung. Der Vergleich der aktiven Massenfunktion mit der gesamten Massenfunktion Schwarzer Löcher zeigt ebenfalls Hinweise auf "AGN downsizing". Als nächstes habe ich mich mit Untersuchungen zur zeitlichen Entwicklung in den Beziehungen zwischen Schwarzem Loch und Galaxie beschäftigt. Diese kann helfen unser theoretisches Veständnis der physikalischen Vorgänge zu verbessern. Beobachtungen sind immer auch Auswahleffekten unterworfen. Diese können die Schlussfolgerungen aus den Beobachtungen zur Entwicklung in den Beziehungen beeinflussen, wenn sie nicht entsprechend berücksichtigt werden. Ich habe den Einfluss von Auswahleffekten auf AGN Stichproben im Detail untersucht, und verschiedende möchgliche Einflussquellen identifiziert, die die Beziehung verfälschen können. Wenn die Auswahlkriterien der Stichprobe, sowie die zugrunde liegenden Verteilungen bekannt sind, so ist es möglich für die Auswahleffekte zu korrigieren. Ich habe eine Methode entwickelt, mit der man die intrinsische Beziehung zwischem Schwarzem Loch und Galaxie aus den Beobachtungen rekonstruieren kann. Schließlich habe ich mich auch inaktiven Schwarzen Löchern und der Bestimmung ihrer Massen gewidmet. Eine der wichtigsten Methoden die Masse Schwarzer Löcher in normalen Galaxien zu bestimmen ist stellardynamische Modellierung. Diese Methode benutzt photometrische und kinematische Beobachtungen, und rekonstruiert daraus das Gravitationspotenzial aus der Analyse stellarer Orbits. Bisher wurde in diesen Modellen allerdings der Einfluss des Halos aus Dunkler Materie vernachlässigt. Dieser kann aber die Bestimmung der Masse des Schwarzen Loches beeinflussen. Ich habe 12 Galaxien mit Hilfe stellardynamischer Modellierung untersucht und dabei auch den Einfluss des Halos aus Dunkler Materie berücksichtigt. Für Galaxien bei denen der Einflussbereich des Schwarzen Loches nicht sehr gut räumlich aufgelöst war, wird die Masse des Schwarzen Loches systematisch unterschätzt, wenn der Dunkle Materie Halo nicht berücksichtigt wird. Auf der anderen Seite ist der Einfluss gering, wenn die Beobachtungen diesen Einflussbereich gut auflösen können.

Astrophysikalische Jets sind stark kollimierte Materieströmungen hoher Geschwindigkeit. Sie stehen im Zusammenhang mit einer Fülle verschiedener astrophysikalischer Objekte wie jungen Sternen, stellaren schwarzen Löchern ('Mikro-Quasare'), Galaxien mit aktivem Kern (AGN) und wahrscheinlich auch mit dem beobachteten intensiven Aufblitzen von Gamma-Strahlung (Gamma Ray Bursts). Insbesondere hat sich gezeigt, dass die Jets der Mikro-Quasare wahrscheinlich als kleinskalige Version der Jets der AGN anzusehen sind. <br /> <br /> Neben den Beobachtungen haben vor allem auch theoretische Überlegungen gezeigt, dass Magnetfelder bei der Jetentstehung, -beschleunigung und -kollimation eine wichtige Rolle spielen. Weiterhin scheinen Jets systematisch verknüpft zu sein mit dem Vorhandensein einer Akkretionsscheibe um das zentrale Objekt. Insbesondere wenn ein schwarzes Loch den Zentralkörper darstellt, ist die umgebende Akkretionsscheibe der einzig mögliche Ort um Magnetfeld erzeugen zu können. <br /> <br /> Wir sind speziell interessiert am Entstehungsprozess hoch relativistischer Jets wie sie bei Mikro-Quasaren und AGN beobachtet werden. Insbesondere untersuchen wir die Region, in der der Jet kollimiert, eine Region, deren räumliche Ausdehnung extrem klein ist selbst im Vergleich zur Auflösung der Radioteleskope. Dies ist ein Grund, wieso zum heutigen Zeitpunkt für die meisten Quellen die theoretische Modellierung die einzige Möglichkeit darstellt, um Information über die physikalischen Prozesse in der innersten Region der Jetentstehung zu erhalten. <br /> <br /> Uns ist es zum ersten Mal gelungen, die globale zwei-dimensionale Magnetfeldstruktur stationärer, axialsymmetrischer, relativistischer und stark magnetisierter (kräfte-freier) Jets zu berechnen, die zum einen asymptotisch in einen zylindrischen Jet kollimieren, zum anderen aber in einer differential rotierenden Akkretionsscheibe verankert sind. Damit erlaubt dieser Ansatz eine physikalische Verkn&#168;upfung zwischen Akkretionsscheibe und dem asymptotischen Jet. Nimmt man also an, dass die Fußpunkte der Magnetfeldlinien mit Keplergeschwindigkeit rotieren, so kann man eine direkte Skalierung der Jetmagnetosphere mit der Größe des Zentralobjektes erhalten. Unsere Resultate zeigen eine gute Übereinstimmung zwischen unserem Modell und Beobachtungen des Jets von M87. <br /> <br /> Für das Beispiel eines relativistischen Mikroquasarjets haben wir die Röntgenemission im Bereich von 0.2-10.1 keV berechnet. Dafür haben wir in der Literatur aus den relativistischen magnetohydrodynamischen Gleichungen berechnete Jetgrößen (Dichte-, Geschwindigkeits-, und Temperaturprofil) verwendet und das Spektrum für jeden Punkt entlang der Jetströmung abgeleitet. Das theoretische thermische Röntgenspektrum des innersten, heißen Teils des Jets erhalten wir zusammengesetzt aus den spektralen Anteilen der einzelnen Volumenelemente entlang des Jets. Um relativistische Effekte wie Dopplerverschiebung und -verstärkung (boosting) aufgrund der Jetbewegung zu untersuchen, haben wir für verschiedene Inklinationswinkel des Jets zur Sichtlinie berechnet, wie die erhaltenen Spektren davon beeinflusst werden. <br /> <br /> Unsere Spektren zeigen deutlich die hochionisierten Eisen-Emissionslinien, die in den galaktischen Mikroquasaren GRS 1915+105 und XTE J1748-288 andeutungsweise beobachtet wurden.<br /> Eine Dopplerverschiebung dieser Linien ist in unseren Spektren deutlichzu sehen. Da die innerste, Röntgenstrahlung emittierende Region des magnetohydrodynamischen Jets allerdings noch unkollimiert ist, spielt Dopplerboosting in unseren Spektren, abhängig vom Sichtwinkel, keine große Rolle. Mit unseren Resultaten konnte zum ersten Mal ein Röntgenspektrum gewonnen werden, das auf der numerischen Lösung eines magnetohydrodynamischen Jets beruht. / Jets are highly collimated flows of matter. They are present in a large variety of astrophysical sources: young stars, stellar mass black holes (microquasars), galaxies with an active nucleus (AGN) and presumably also intense flashes of gamma-rays. In particular, the jets of microquasars, powered by accretion disks, are probably small-scale versions of the outflows from AGN. <br /> <br /> Beside observations of astrophysical jet sources, also theoretical considerations have shown that magnetic fields play an important role in jet formation, acceleration and collimation. Collimated jets seem to be systematically associated with the presence of an accretion disk around a star or a collapsed object. If the central object is a black hole, the surrounding accretion disk is the only possible location for a magnetic field generation. <br /> <br /> We are interested in the formation process of highly relativistic jets as observed from microquasars and AGN. We theoretically investigate the jet collimation region, whose physical dimensions are extremely tiny even compared to radio telescopes spatial resolution. Thus, for most of the jet sources, global theoretical models are, at the moment, the only possibility to gain information about the physical processes in the innermost jet region.<br /> <br /> For the first time, we determine the global two-dimensional field structure of stationary, axisymmetric, relativistic, strongly magnetized (force-free) jets collimating into an asymptotically cylindrical jet (taken as boundary condition) and anchored into a differentially rotating accretion disk. This approach allows for a direct connection between the accretion disk and the asymptotic collimated jet. Therefore, assuming that the foot points of the field lines are rotating with Keplerian speed, we are able to achieve a direct scaling of the jet magnetosphere in terms of the size of the central object. We find a close compatibility between the results of our model and radio observations of the M87 galaxy innermost jet.<br /> <br /> We also calculate the X-ray emission in the energy range 0.2--10.1,keV from a microquasar relativistic jet close to its source of 5 solar masses. In order to do it, we apply the jet flow parameters (densities, velocities, temperatures of each volume element along the collimating jet) derived in the literature from the relativistic magnetohydrodynamic equations. We obtain theoretical thermal X-ray spectra of the innermost jet as composition of the spectral contributions of the single volume elements along the jet. Since relativistic effects as Doppler shift and Doppler boosting due to the motion of jets toward us might be important, we investigate how the spectra are affected by them considering different inclinations of the line of sight to the jet axis. <br /> <br /> Emission lines of highly ionized iron are clearly visible in our spectra, probably also observed in the Galactic microquasars GRS 1915+105 and XTE J1748-288. The Doppler shift of the emission lines is always evident. Due to the chosen geometry of the magnetohydrodynamic jet, the inner X-ray emitting part is not yet collimated. Ergo, depending on the viewing angle, the Doppler boosting does not play a major role in the total spectra. This is the first time that X-ray spectra have been calculated from the numerical solution of a magnetohydrodynamic jet.

Made available in DSpace on 2016-03-15T19:37:53Z (GMT). No. of bitstreams: 1 Marcio Ribeiro Gastaldi.pdf: 1118514 bytes, checksum: 0da632ad9d5d56b0c1ab1df75e83eee3 (MD5) Previous issue date: 2007-02-02 / We present the results of a 2-year project to monitor the spectral and temporal variability of Sagittarius A, Centaurus A, OV236 and the Einstein s Ring PKS1830-211 from 2004 to 2006. The observational data were obtained from the Itapetinga Radio Telescope at 22 and 43GHz. The data at 4,8, 8,0 and 14,5GHz for OV236 and PKS1830-211 were taken from the Michigan Radio Observatory. We also obtained previous observations of OV236 and PKS1830-211 at 100 and 230GHz from the Swedish-ESO Sub Millimeter Telescope (SEST), and VLA 23 and 43GHz data for Sgr A*. We estimated parameters such as period, angular size and brightness temperature and applied the Shock Wave Model (MARSHER; GEAR 1985) for OV236. The work we present here results from an international cooperation among Brazil (Itapetinga at 22 and 43GHz), EUA (Michigan at 4,8, 8,0 and 14,5GHz, and the VLA at 23 and 43GHz) and Finland (Metsähovi at 90GHz). / Este trabalho mostra o estudo da variabilidade temporal e espectral de Sagittarius A, Centaurus A, OV236 e do anel de Einstein PKS1830-211 em campanhas de observação mensais realizadas de janeiro de 2004 a outubro de 2006. Os dados observacionais foram obtidos através do Rádio-Observatório do Itapetinga nas freqüências de 22 e 43GHz. Os dados em 4,8, 8,0 e 14,5GHz para OV236 e PKS1830-211 foram obtidos do Rádio-Observatório de Michigan. Também foram utilizados dados do SEST para OV236 em 100 e 230GHz, e dados do VLA em 23 e 43GHz para Sgr A*. Foram feitas estimativas de período, variação angular e temperatura de brilhância. O modelo de Marscher e Gear (1985) foi aplicado a OV236. Este é um trabalho de cooperação internacional entre Brasil (Itapetinga em 22 e 43GHz), Estados Unidos (Michigan em 4,8, 8,0 e 14,5 GHz e VLA em 23 e 43GHz) e Finlândia (Metsähovi em 90GHz).

Active galaxies have been in the forefront of astronomic research since their first discovery, at least 50 years ago (e.g. Schmidt, 1963; Matthews & Sandage, 1963). The putative supermassive black hole (SMBH) at their center characterizes their properties and regulates the evolution of these objects. In this thesis, I study the 'demographics' and 'ecology' of active galactic nuclei (AGN) in the context of their evolution and the interaction with their environments (mainly their host galaxy). The number density of AGN has been found to peak at 1 < z < 3 (e.g. Ueda et al., 2003; Hasinger et al., 2005; Richards et al., 2005; Aird et al., 2010), similar to the star formation history (e.g. Silverman et al., 2008a; Aird et al., 2010). However, when taking into account obscuration, faint AGN are found to peak at lower redshift (z ≤ 2) than that of bright AGN (z ≈ 2 - 3; e.g. Hasinger et al., 2005; Hopkins et al., 2007; Xue et al., 2011). This qualitative behaviour is also broadly seen in star-forming galaxies (e.g. Cowie et al., 1996) and is often referred to as 'cosmic downsizing', although this term has developed a number of usages with respect to galaxies (e.g. Bundy et al., 2006; Cimatti et al., 2006; Faber et al., 2007; Fontanot et al., 2009). Though this behaviour is well established up to z ≈ 3, the nature of how and when the initial seed of these AGNs were formed remains an open question. For this study, I use Chandra surveys to study some of the most distant AGN in the Universe (z > 3). The combination of two different size and depth Chandra surveys (Chandra-COSMOS and ChaMP) provides me with the largest to-date z > 3 AGN sample, over a wide range of rest-frame 2-10 keV luminosities [log (Lₓ/erg s⁻¹) = 43.3-46.0] and obscuration (NH = 10²⁰ - 10²³ cm⁻²). I find strong evidence about a strong decline in number density of X-ray AGN above z ≈ 3, and also the association of this decline with a luminosity-dependent density evolution (LDDE; e.g. Gilli et al., 2007). Especially at high redshifts, the different evolution models predict quite different numbers of AGNs. The large size and the wide X-ray luminosity range of this sample reduces the uncertainties of previous studies at similar redshifts making it possible to distinguish between the different models and suggest that observations appear to favour the LDDE model. The observed AGN downsizing behaviour seen via the measured X-ray luminosity function (XLF) could arise due to changes in the mass of the typical active SMBH and/or changes in the typical accretion rate. But how does the growth of SMBHs over cosmic time influence its environment? A powerful way to address this question is to compare the host galaxy properties over a wide range of AGN and accretion rate types. Radio-jets are one of the most prominent constituents of AGN as they can interact directly with the host galaxy. Although AGN with radio jets are rare (they make up to 10 per cent of the total AGN population) radio galaxies make up over 30 per cent of the massive galaxy population and it is likely that all massive galaxies go through a radio-loud phase, as the activity is expected to be cyclical (e.g Best et al., 2005). It is therefore, important to investigate the impact of radio jets on the host galaxy and particularly the star formation. The method I follow focuses on the comparison of the host galaxy properties between optically selected quasar samples, with and without strong radio emission associated with powerful radio-jets, matched in AGN luminosity. Herschel far-infrared observations are used to trace the star formation in the host galaxy, providing minimal AGN contamination. In my first approach, I have constructed a sample of radio-loud and radio-quiet quasars from the Faint Images Radio Sky at Twenty-one centimetres (FIRST) and the Sloan Digital Sky Survey Data Release 7 (SDSS DR7), over the H-ATLAS Phase 1 Area (9h, 12h and 14.5h). The main result of this work is that RLQs at lower AGN luminosities tend to have on average higher FIR and 250-μm luminosity with respect to RQQs matched in AGN luminosity and redshift. However, evolution effects could be strong as the quasars in this sample cover a wide range of redshifts (0.4 < z < 5). Therefore, I follow a second approach with the advantage of a QSO sample selection at a single redshift epoch, decomposing the evolution effects from the AGN/star-formation study. The results indicate that radio-jets in powerful QSOs can both suppress and enhance the star formation in their host galaxies. These fundings are consistent with a galaxy mass and jet-power dependence model. Then we expect more massive galaxies to have more star-formation for a given jet-power because their star-formation is more enhanced by the jet. Although radio-jets are the best candidates for a direct AGN impact to the host galaxy, many models refer to an AGN feedback associated with energetic AGN winds and outflows which are expected to suppress the star formation in powerful AGN when compared to the overall galaxy population. My results do not suggest star formation is suppressed in the hosts of optically selected QSOs at z ≈ 1, with more than 30 per cent of them being associated with strong star formation rates (SFR ≈ 350 M⊙ yr⁻¹). Although different interpretations are possible, this result can be explained through periods of enhanced AGN activity and star-forming bursts, possibly through major mergers. However, optical QSOs comprise only a small fraction of the total AGN population. Even if the 'unified model' predicts that the host galaxy properties should not be affected by the viewing angle (type-1 vs. type-2 AGN), several studies have shown results supporting a scenario departing from the basic model. Investigating star formation in the hosts of 24 μm selected type-1&2 AGN, I found that the type-2 AGNs display on average higher star-formation rate than type-1 AGNs. This result is in agreement with previous studies suggesting an undergoing transition between a hidden growth phase and an unobscured AGN phase.

Nesse trabalho, foi feito o tratamento e a análise de cubos de dados de 8 núcleos ativos de galáxias próximos, no óptico e no infravermelho. O tratamento e a análise de todos os cubos de dados foram feitos utilizando-se uma série de metodologias específicas, muitas das quais foram desenvolvidas nos últimos anos pelo grupo de trabalho do autor. A análise de todos os cubos de dados foi feita com quatro objetivos principais: análise da fenomenologia geral nos arredores do AGN com a Tomografia PCA; análise das populações estelares, da emissão térmica de poeira e do featureless continuum nos arredores do AGN com uma síntese espectral feita com o software Starlight; análise da cinemática estelar e do gás ao redor do buraco negro central e, em alguns casos, simulação com o objetivo de se determinar a massa do buraco negro; análise dos mecanismos de excitação e ionização do gás ou da emissão de hidrogênio molecular. / In this work, we have treated and analyzed data cubes of 8 nearby active galactic nuclei, in the optical and in the infrared. All data cube treatment and analysis were performed using a series of specific methodologies, many of which were developed in the last few years by the author\'s working group. The analysis of all data cubes was performed with four main objectives: analysis of the general phenomenology of the AGN environment, using PCA Tomography; analysis of the stellar populations, of the thermal emission from dust and of the featureless continuum in the vicinity of the AGN, with a spectral synthesis performed with the Starlight software; analysis of the stellar and gas kinematics around the central black hole and, in some cases, simulations with the purpose of determining the mass of the black hole; analysis of the excitation and ionization mechanisms of the gas or of the emission from molecular hydrogen.

In this thesis, I investigate the spatial distribution of radio sources, and quantify their clustering strength over a range of redshifts, up to z _ 2:2, using various forms of the correlation function measured with data from several multi-wavelength surveys. I present the optical spectra of 30 radio AGN (S1:4 > 100 mJy) in the GAMA/H-ATLAS fields, for which emission line redshifts could be deduced, from observations of 79 target sources with the EFOSC2 spectrograph on the NTT. The mean redshift of these sources is z = 1:2; 12 were identified as quasars (40 per cent), and 6 redshifts (out of 24 targets) were found for AGN hosts to multiple radio components. While obtaining spectra for hosts of these multi-component sources is possible, their lower success rate highlights the difficulty in acheiving a redshift-complete radio sample. Taking an existing spectroscopic redshift survey (GAMA) and radio sources from the FIRST survey (S1:4 > 1 mJy), I then present a cross-matched radio sample with 1,635 spectroscopic redshifts with a median value of z = 0:34. The spatial correlation function of this sample is used to find the redshiftspace (s0) and real-space correlation lengths (r0 _ 8:2 h 1Mpc), and a mass bias of _1.9. Insight into the redshift-dependence of these quantities is gained by using the angular correlation function and Limber inversion to measure the same spatial clustering parameters. Photometric redshifts from SDSS/UKIDSS are incorporated to produce a larger matched radio sample at z ' 0:48 (and low- and high-redshift subsamples at z ' 0:30 and z ' 0:65), while their redshift distribution is subtracted from that taken from the SKADS radio simulations to estimate the redshift distribution of the remaining unmatched sources (z ' 1:55). The observed bias evolution over this redshift range is compared with model predictions based on the SKADS simulations, with good agreement at low redshift. The bias found at high redshift significantly exceeds these predictions, however, suggesting a more massive population of galaxies than expected, either due to the relative proportions of different radio sources, or a greater typical halo mass for the high-redshift sources. Finally, the reliance on a model redshift distribution to reach to higher redshifts is removed, as the angular cross-correlation function is used with deep VLA data (S1:4 > 90 _Jy) and optical/IR data from VIDEO/CFHTLS (Ks < 23:5) over 1 square degree. With high-quality photometric redshifts up to z _ 4, and a high signal-to-noise clustering measurement (due to the _100,000 Ks-selected galaxies), I am able to find the bias of a matched sample of only 766 radio sources (as well as of v vi the VIDEO sources), divided into 4 redshift bins reaching a median bias at z ' 2:15. Again, at high redshift, the measured bias appears to exceed the prediction made from the SKADS simulations. Applying luminosity cuts to the radio sample at L > 1023 WHz 1 and higher (removing any non-AGN sources), I find a bias of 8–10 at z _ 1:5, considerably higher than for the full sample, and consistent with the more numerous FRI AGN having similar mass to the FRIIs (M _ 1014 M_), contrary to the assumptions made in the SKADS simulations. Applying this adjustment to the model bias produces a better fit to the observations for the FIRST radio sources cross-matched with GAMA/SDSS/UKIDSS, as well as for the high-redshift radio sources in VIDEO. Therefore, I have shown that we require a more robust model of the evolution of AGN, and their relation to the underlying dark matter distribution. In particular, understanding these quantities for the abundant FRI population is crucial if we are to use such sources to probe the cosmological model as has been suggested by a number of authors (e.g. Raccanelli et al., 2012; Camera et al., 2012; Ferramacho et al., 2014).

This thesis presents a detailed study of the impact of radio-AGN on star formation and the interstellar medium (ISM) of galaxies across cosmic time. To do this, this thesis uses far-IR/sub-mm data from the Herschel Space Observatory. I create a well-selected sample of 1599 radio sources using the NRAO VLA Sky Survey (NVSS) and Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) data in combination with the UKIRT Infrared Deep Sky Survey - Large Area Survey (UKIDSS - LAS) data. I find that the far-IR luminosities and dust temperatures of radio galaxies are lower in comparison to those of non-radio-detected galaxies. This luminosity deficit grows with increasing stellar mass. I argue that the reasons for these differences is probably due to indirect radio-AGN feedback, i.e. radio jets mechanically heat the halo-environment, preventing external sources of cold gas from entering the host and forming stars. The far-IR luminosity and dust temperature is found to decrease as a function of radio source size. I find the most likely explanation for this is jet-induced star formation while the jets are confined to the ISM. Finally, a method for identifying reliable high-z, star-bursting radio sources in the H-ATLAS is described with which statistically significant studies of radio-jet induced star formation may be undertaken.

Blazars, a subclass of active galactic nuclei with powerful relativistic plasma jets, are among the most luminous and violently variable objects in the universe. They emit radiation across the entire electromagnetic spectrum, and often change in brightness over the course of hours or days. Different emission mechanisms are necessary in order to explain the observed flux in different frequency ranges. In the ultraviolet-optical- infrared regime these include components that arise from: 1) polarized synchrotron radiation emanating from a powerful parsec-scale jet flowing from near the central accreting black hole, 2) a multi-temperature accretion disk emitting thermal radia- tion, and 3) an optically thick dusty torus located several parsecs from the central engine that absorbs and re-emits, at infrared wavelengths, radiation originating in the accretion disk. The goal of this study is to determine the relative importance of these spectral components in the spectra of blazars. I use data from the Spitzer Space Telescope in order to search for the presence of the dusty torus surrounding four blazars, as well as to determine its luminosity and temperature. In two of the observed sources, 1222+216 and CTA102, I determine that the torus can be modeled as a 1200 K blackbody emitting at nearly 10 46 erg s −1 . Furthermore, I determine the relative variability of the accretion disk of a sample of blazars by using spec- tropolarimetry observations to separate the optical-UV spectrum into a polarized viiicomponent, consisting of radiation described by a power-law F ν ∝ ν −α , and an ac- cretion disk which consists of a thin disk described by the power-law F disk ∝ ν 1/3 plus a hot-spot of variable temperature. The spectra of several blazars are explained by a version of this model in which the thin disk component is held constant, while the blackbody varies on timescales of approximately years resulting with a flux of the blackbody component comparable to the power-law disk component. I find that variations in the emission from the hot-spot occurs approximately within 100 days of γ-ray variations.

The goal of galaxy classification is to understand the physical basis for the wide range in shapes and structures exhibited by galaxies in the local and high redshift universe. We present a catalog of visually classified galaxies from the Sloan Digital Sky Survey with detailed morphological classifications including bars, rings, lenses, tails, warps, dustlanes, arm flocculence and multiplicity (so called ’fine structure’). This thesis explores the importance of galaxy morphology by probing its relationship to physical properties. Our analysis includes an investigation of correlations between fine structures and AGN activity. This sample defines a comprehensive local galaxy sample which we use to study the low redshift universe both qualitatively and quantitatively. We find the stellar mass appears to be a defining characteristic of a galaxy. The break in most correlations of physical properties with morphology is due to a lack of late type, massive disk galaxies. Our analysis of the size-mass relations of galaxies as a function of morphology (T-Type) has revealed many interesting connections. We find the size-mass relation of Sa, Sab, Sb, and Sbc galaxies bifurcates into two families of objects as one moves down the sequence such that the high concentration branch exhibits a similar slope to low concentration early type (E) galaxies suggesting a closer than expected physical (possibly evolutionary) connection between the two populations. We find bar fraction is bimodal with respect to mass (at 3 x 10^10 M) and color (at g - r ∼ 0.55). The dependence is seen to intimately depend on central concentration such that objects below the transition mass with low concentrations have a higher bar fraction than objects above the transition mass which have high bar fractions for high concentration systems. In addition we find the presence of an AGN alters the behavior and abundance of barred/ringed galaxies in the high mass peak such that the bar/ring fractions increase with mass in nonactive galaxies whereas they decrease with mass in active galaxies. AGN fractions are also decreasing in the same mass range possibly implying a positive correlation between fine structure and ring formation.