Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / We have mapped emission-line flux distributions and ratios as well as the gaseous kinematics of the inner 450 pc radius of the Seyfert galaxy Mrk 766 using integral field near-IR J- and Kl-band spectra obtained with the Gemini North instrument NIFS at a spatial resolution of ≈60 pc and velocity resolution of ≈40 kms−1. Emission-line flux distributions in Pa β and Brγ extend to ≈300 pc from the nucleus in all directions, while the [Fe II] emission is extended to a similar distance but mostly along PA≈130◦. The coronal lines traced by [S IX] are resolved, presenting emission up to ≈150 pc from the nucleus. The molecular H2 gas emission is extended also to ≈300 pc from the nucleus but along PA≈50º, approximately perpendicularly to the orientation of the [Fe II] emission. The H2 gas has an excitation temperature Texc = 2360±45K and its emission is dominated by thermal processes, mainly due X-ray heating by the active nucleus. The [Fe II] emission seems also to be produced by these thermal processes, but with an important contribution from shocks, as evidenced by the correlation between enhanced [Fe II]/[P II] line ratios, the [Fe II] velocity dispersion and the radio structure. The gas velocity field is dominated by rotation, and the fit of a circular model gives a position angle of 59º for the line of nodes, which is the approximate orientation of the extended H2 emission. This fact, combined with the low H2 velocity dispersion close to the velocity resolution of the data supports a location of the H2 emitting gas in the galaxy plane, and its association with the feeding of the supermassive black hole. There is about 103 M⊙ of hot H2, implying ≈109 M⊙ of cold molecular gas in the inner 450 pc radius. On the other hand, the higher velocity dispersion (150 kms−1) for [Fe II] to the southeast of the nucleus, and the presence of both blueshifts and redshifts in the channel maps at the corresponding locations, supports the presence of an outflow to the southwest with an axis lying close to the plane of the sky. The ionized gas outflow rate is estimated to be 2.18 M⊙ yr−1, and the power of the outflow 0.011 Lbol. The distinct flux distributions and kinematics of the H2 and [Fe II] emitting gas, with the first more restricted to the plane of the galaxy and in rotation and the second related with the radio jet and in outflow are common characteristics of 8 Seyfert galaxies (ESO428-G14, NGC4051, NGC7582, NGC4151, Mrk 1066, Mrk 1157, Mrk 79 and Mrk 766) we have studied so far using similar integral-field observations and 2 others (Circinus and NGC2110) using long-slit observations. These results support the conclusion that the H2 emission is tracer of the AGN feeding, while the [Fe II] is a tracer of its feedback. / Mapeamos as distribuições de fluxos de linhas de emissão e suas razões bem como a cinemática do gás nos 450 pc centrais da galáxia Seyfert Mrk 766 usando espectroscopia de campo integral (IFS) na região do infravermelho próximo nas bandas J e Kl obtidas com o instrumento NIFS do telestcópio Gemini-Norte com uma resolução espacial de ≈ 60 pc e resolução espectral de ≈ 40 km s−1. As distribuições de fluxos das linhas de emissão de Paβ e Brγ se estendem até ≈ 300 pc do núcleo em todas as direções, enquanto a emissão do [Fe II] se estende até uma distância similar, porém, mais concentrada ao longo do PA≈ 130º. As linhas coronais traçadas pelo [S IX] são resolvidas, apresentando emissão até ≈ 150 pc do núcleo. A emissão do H2 molecular é estendida também a ≈ 300 pc do núcleo, mas, ao longo do PA ≈ 50º, aproximadamente perpendicular a orientação da emissão do [Fe II]. O gás H2 tem uma temperatura de excitação Texc = 2360 ±45 K e sua emissão é dominada por processos térmicos, principalmente devido a aquecimento do gás por raios-X provenientes do núcleo ativo. A emissão do [Fe II] também parece ser produzida por esses processos térmicos, mas com uma importante contribuição dos choques, assim como evidenciado pela razão [Fe II]/[P II] e por aumentos na dispersão de velocidades associados com o jato rádio. e a estrutura rádio. O campo de velocidades do gás é dominado por rotação, e o ajuste de um modelo de órbitas circulares no plano da galáxia nos dá um ângulo de posição de 59º para a linha dos nodos, o que parece ser aproximadamente a orientação da elongação da emissão do H2. Este fato, combinado com a baixa dispersão de velocidades do H2 é consistente com emissão de gás localizado no plano da galáxia e sua associação com a alimentação do buraco negro supermassivo. Há aproximadamente 103 M⊙ de H2 quente, implicando em ≈ 109 M⊙ de gás molecular frio no interior dos 450 pc centrais. Por outro lado, a maior dispersão de velocidades para o [Fe II] (150 km s−1) a sudeste do núcleo, e a presença tanto de blueshifts quanto redshifts nos mapas de fluxo para diferentes velocidades nas correspondentes localizações, apoiam a presença de um outflow a sudeste, orientado próximo ao plano do céu. A taxa de outflow de gás ionizado é estimada em 2.18 M⊙ ano−1 e sua potência em 0.011 Lbol. As distintas distribuições de fluxo e cinemática do H2 e do [Fe II], com o primeiro mais restrito ao plano da galáxia e em rotação e o segundo relacionado com o jato rádio e em outflow são características comuns de 8 galáxias Seyferts (ESO 428-G14, NGC4051, NGC 7582, NGC 4151, Mrk 1066, Mrk 1157, Mrk 79 e Mrk 766) que foram estudadas por nosso grupo até agora, usando IFS e 2 outras (Circinus e NGC 2110) usando esoectroscopia de fenda longa. Estes resultados apoiam a conclusão de que a emissão do H2 é um traçador da alimentação do núcleo ativo, enquanto o [Fe II] é um traçador de seu feedback.

Le blazar Mrk 501 possède un spectre d'émission non thermique présentant deux composantes. La première, dominant entre le domaine radio et celui des rayons X, correspond à l'émission synchrotron du jet magnétisé, tandis que l'origine de la seconde, dans le domaine gamma de haute énergie, demeure encore sujette à discussion. Jusqu'en 1999, ce dernier domaine d'énergie n'avait été couvert qu'entre 100 MeV et 4 GeV, ainsi qu'au-dessus de 300 GeV. La mise en place de l'expérience CELESTE a comblé la fenêtre d'énergie manquante : observation de l'émission Tcherenkov produite par les rayons gamma d'énergie entre 50 et 350 GeV pénétrant l'atmosphère. Source variable, Mrk 501 a ainsi été observée en 2000 et 2001, détectée en 2000 avec calcul de son flux permettant de contraindre les modèles d'émission à haute énergie.<br />Cette thèse présente la démarche effectuée jusqu'à la détection de Mrk 501 : dans un premier temps, par la validation de l'analyse utilisée sur des observations de la nébuleuse du Crabe, chandelle standard des télescopes Tcherenkov atmosphériques ; puis la détermination des coupures d'analyse, dépendantes de la région du ciel pointée, à partir d'observations du blazar Mrk 421, de même déclinaison que Mrk 501, dont la forte activité permet une détection claire. Enfin, des simulations, tenant compte de la qualité de l'atmosphère et améliorées pour mieux reproduire le détecteur, ont permis d'établir la surface effective de l'instrument pour en déduire le flux de Mrk 501 entre avril et juin 2000. Ce flux a été comparé avec un modèle d'émission de type synchrotron self-Compton et avec des données prises en rayons X. Elles indiquent que Mrk 501 apparaissait légèrement plus actif durant cette période par rapport au reste de l'année et à l'année 2001. Une limite supérieure au flux est calculée pour l'ensemble des autres mesures. C'est une première mesure dans le domaine d'énergie 50 - 350 GeV (gamme représentant les limites en énergie pour lesquelles le taux de comptage, c'est-à-dire la convolution du spectre de l'astre avec la surface effective de collection de l'instrument, se révèle supérieur à 20 % du maximum de comptage). Elle apporte des contraintes sur la position du maximum d'émission Compton inverse et tend à favoriser, dans ce cas précis, des processus d'émission X et gamma par deux populations d'électrons différentes (la variation dans le domaine X est faible comparée à celle du domaine gamma).

We investigate the origin of the parsec-scale radio emission from the changing-look active galactic nucleus (AGN) of Mrk 590, and examine whether the radio power has faded concurrently with the dramatic decrease in accretion rates observed between the 1990s and the present. We detect a compact core at 1.6 and 8.4 GHz using new Very Long Baseline Array observations, finding no significant extended, jet-like features down to similar to 1 pc scales. The flat spectral index (alpha(8.4)(1.6) = 0.03) and high brightness temperature (T-b similar to 10(8) K) indicate self-absorbed synchrotron emission from the AGN. The radio to X-ray luminosity ratio of log(L-R/L-X) similar to -5, similar to that in coronally active stars, suggests emission from magnetized coronal winds, although unresolved radio jets are also consistent with the data. Comparing new Karl G. Jansky Very Large Array measurements with archival and published radio flux densities, we find 46 per cent, 34 per cent, and (insignificantly) 13 per cent flux density decreases between the 1990s and the year 2015 at 1.4 GHz, 5 GHz and 8.4 GHz, respectively. This trend, possibly due to the expansion and fading of internal shocks within the radio-emitting outflow after a recent outburst, is consistent with the decline of the optical-UV and X-ray luminosities over the same period. Such correlated variability demonstrates the AGN accretion-outflow connection, confirming that the changing-look behaviour in Mrk 590 originates from variable accretion rates rather than dust obscuration. The present radio and X-ray luminosity correlation, consistent with low/hard state accretion, suggests that the black hole may now be accreting in a radiatively inefficient mode.

We investigate the multiwavelength behaviour of the high-energy peaked BL Lac object (HBL) Mrk 421 at redshift z = 0.031 in the period 2007-2015. We use optical photometric, spectroscopic, and polarimetric data and near-infrared data obtained by 35 observatories participating in the GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT), as well as by the Steward Observatory Support of the Fermi Mission. We also employ high-energy data from the Swift (UV and X-rays) satellite to study correlations among emission in different bands.

We report on long-term multiwavelength monitoring of blazar Mrk 421 by the GLAST-AGILE Support Program of the Whole Earth Blazar Telescope (GASP-WEBT) collaboration and Steward Observatory, and by the Swift and Fermi satellites. We study the source behaviour in the period 2007-2015, characterized by several extreme flares. The ratio between the optical, X-ray and gamma-ray fluxes is very variable. The gamma-ray flux variations show a fair correlation with the optical ones starting from 2012. We analyse spectropolarimetric data and find wavelength-dependence of the polarization degree (P), which is compatible with the presence of the host galaxy, and no wavelength dependence of the electric vector polarization angle (EVPA). Optical polarimetry shows a lack of simple correlation between P and flux and wide rotations of the EVPA. We build broad-band spectral energy distributions with simultaneous near-infrared and optical data from the GASP-WEBT and ultraviolet and X-ray data from the Swift satellite. They show strong variability in both flux and X-ray spectral shape and suggest a shift of the synchrotron peak up to a factor of similar to 50 in frequency. The interpretation of the flux and spectral variability is compatible with jet models including at least two emitting regions that can change their orientation with respect to the line of sight.

Star formation occurs when the gas (mostly atomic hydrogen; H I) in a galaxy becomes disturbed, forming regions of high density gas, which then collapses to form stars. In dwarf galaxies it is still uncertain which processes contribute to star formation and how much they contribute to star formation. Blue compact dwarf (BCD) galaxies are low mass, low shear, gas rich galaxies that have high star formation rates when compared to other dwarf galaxies. What triggers the dense burst of star formation in BCDs but not other dwarfs is not well understood. It is often suggested that BCDs may have their starburst triggered by gravitational interactions with other galaxies, dwarf-dwarf galaxy mergers, or consumption of intergalactic gas. However, there are BCDs that appear isolated with respect to other galaxies, making an external disturbance unlikely. Here, I study six apparently isolated BCDs from the LITTLE THINGS1sample in an attempt to understand what has triggered their burst of star formation. LITTLE THINGS is an H I survey of 41 dwarf galaxies. Each galaxy has high angular and velocity resolution H I data from the Very Large Array (VLA) telescope and ancillary stellar data. I use these data to study the detailed morphology and kinematics of each galaxy, looking for signatures of starburst triggers. In addition to the VLA data, I have collected Green Bank Telescope data for the six BCDs. These high sensitivity, low resolution data are used to search the surrounding area of each galaxy for extended emission and possible nearby companion galaxies. The VLA data show evidence that each BCD has likely experienced some form of external disturbance despite their apparent isolation. These external disturbances potentially seen in the sample include: ongoing/advanced dwarf-dwarf mergers, an interaction with an unknown external object, and external gas consumption. The GBT data result in no nearby, separate H I companions at the sensitivity of the data. These data therefore suggest that even though these BCDs appear isolated, they have not been evolving in isolation. It is possible that these external disturbances may have triggered the starbursts that defines them as BCDs. 1Local Irregulars That Trace Luminosity Extremes, The H I Nearby Galaxy Survey; https://science.nrao.edu/science/surveys/littlethings

In dieser Veröffentlichung soll untersucht werden, ob vorhandene Methoden aus dem Bereich der sozio-technischen Systeme (STS) genutzt werden können, um Mensch-Roboter-Kollaborationen (MRK) hinsichtlich ihrer Ergonomie zu optimieren. [... aus der Einleitung]