Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 24 for “"agns"”.
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Spectral Energy Distribution Modelling of X-ray Selected AGNs and Their Host Galaxies
The nature of the relation between active galactic nuclei (AGN), and their host galaxies have been observed in detail throughout the Universe. Such work has found an intrinsic link between central supermassive black hole (SMBH) masses, and host galaxy properties such as the velocity dispersion of …
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The Relationship of Active Galactic Nuclei & Quasars With Their Local Galaxy Environment
… related to properties of active galactic nuclei (AGNs) of various luminosities. Recent simulations and observations are converging on the view that the extreme luminosity of quasars, the brightest of AGNs, is fueled in major mergers of gas-rich galaxies. In such a picture, quasars, the highest …
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Towards a complete census of active galactic nuclei in the nearby Universe
… galaxies that harbour active galactic nuclei (AGNs), provide constraints on the growth of local SMBHs, and further our understanding towards the connection between AGN activity and galaxy evolution. In the first part of this thesis, we use high-quality mid-infrared (IR) spectroscopy to …
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Optical surveys of AGN and their host galaxies
… rests on two large Active Galactic Nuclei (AGNs) surveys. The first survey deals with galaxies that host low-level AGNs (LLAGN) and aims at identifying such galaxies by quantifying their variability. While numerous studies have shown that AGNs can be variable at all wavelengths, the nature …
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The Active Phases of a Galaxy in the JWST and Euclid Era: From Radio Jets and Multiphase Outflows to Mergers
… focusing on the role of active galactic nuclei (AGNs). AGN feedback, in the form of energy flows and radio jets, is a fundamental mechanism that regulates star formation, redistributes gas and dust, and shapes the structure of the host galaxy. Another phenomenon that affects galactic evolution is …
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Black Holes, Galaxy Clusters and Gravitational Waves
… black holes (SMBHs) and Active Galactic Nuclei (AGNs) in three different environments. SMBHs and radio-AGNs are concentrated in dense environments. The Black Hole Fundamental Plane predicts X-ray properties for our SMBHs and unifies modes of AGN activity in terms of the rate of accretion. …
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The high-redshift clusters occupied by bent radio AGN (COBRA) survey
… and high redshift are active galactic nuclei (AGNs). Specifically, bent, double-lobed radio sources are commonly found in clusters. I find high-redshift clusters hosting bent AGNs and explore their evolution and red sequence galaxies over cosmic time. To characterize cluster evolution, I …
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Unveiling fundamental physics with high-resolution X-ray spectroscopy of Active Galactic Nuclei.
… spectroscopy of active galactic nuclei (AGNs) to probe fundamental physics. It focuses on the study of axion-like particles (ALPs) and the spin of supermassive black holes (SMBHs). Chapter 1 starts with a review of black holes as mathematical and astronomical objects and provides an …
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Reverberation mapping of Active Galactic Nuclei
… to the overall sample of active galactic nuclei (AGNs) with central super-massive black hole (SMBH) mass estimates using reverberation mapping (RM) technique. RM makes use of the time variability of the broad emission lines from the nearby broad-line region (BLR) to measure their time response or …
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Spatial modelling and analysis of wireless ad-hoc and sensor networks: an energy perspective
… The network makes use of aggregation nodes (AGNs), for compression and/or data fusion of locally sensed data. Since the aggregated data may cause a concentration of energy burdens when routed to sinks, we use proactive multipath routing between AGNs to mobile sinks. We show that the scale of …
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Far-UV to Mid-IR Spectral Energy Distributions of Nearby Merging Galaxies
… previously identified as Seyfert or WISE AGNs generally have a higher SED AGN luminosity. I do not find an increased occurrence of SED-detected AGNs in merging over control galaxies, rejecting our study hypothesis. To meet the interdisciplinary requirements of this degree, I also design a …
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Black hole masses and host galaxy properties in distant quasars from reverberation mapping surveys
… black holes (SMBHs), active galactic nuclei (AGNs) and quasars (the most luminous AGNs) are the keys to many outstanding questions in astronomy, including black hole (BH) demographics, BH-host galaxy (co)-evolution, and AGN feedback mechanisms. Reverberation mapping (RM) is the primary …
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Hunting Supermassive Black Holes in the Early Universe
… quest to characterize the earliest and faintest AGNs. We developed quasar survey by joining the next generation Rubin Legacy Survey of Space and Time (LSST) and Roman High-Latitude Wide Area Survey (HLWAS). We extend current empirical simulation of quasars and contaminants, low-redshift red …
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O gás ionizado em galáxias ativas
… de 29 galáxias que hospedam núcleos ativos (AGNs), sendo 6 galáxias Seyfert 1, 18 galáxias Seyfert 2, 4 Rádio-galáxias de linhas estreitas (NLRG) e 1 Rádio-galáxia de linhas largas (BLRG). Estas galáxias apresentam emissão por gás de alta excitação que se estende em alguns casos a 10 kpc do …
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Dynamics of dense gas-star systems : Black holes and their precursors
… observed in all types of galaxies, including AGNs and quasars, some of the most powerful objects in the universe. The interactions between the stellar system and the central black hole give rise to a lot of interesting phenomena. The scheme we employ enables a study of clean-cut aspects …
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AGN outflows and the cluster cooling flow conundrum
… molecular clouds. Active galactic nuclei (AGNs) are thought to be able to counter catastrophic cooling. This thesis provides an overview of the theory and design philosophy of hydrodynamical simulations and a hydrodynamical code called FLASH, which was created by Fryxell et al. (2000). This …
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Commensal searches for radio transients variables in the data from Mhongoose Large Survey Project
… and are classified as active galactic nuclei (AGNs). One radio transient was found in the NGC 1566 field “SRC76717”, which is associated with a nearby flaring M dwarf located at a distance of 48 pc (Doyle et al., 2019).
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An investigation into the effects of shape and structure on the antibacterial efficacy of metal nanoparticles
… obtained in vitro such as spherical shape NPs (AgNS, AuNS and CuNS), octahedron (AgNOct and AuNOct) and cube shapes (CuNC). All produced NPs are crystalline in nature, confirmed by selected area electron diffraction. The MICs of AgNOct against E. coli were the lowest at 10μg/ml, followed by MICs …
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The very high energy gamma ray burst GRB190114C as observed by MeerKAT
… we find are likely active galactic nuclei (AGNs), and their variability in this context is reasonably due to interstellar scintillation as derived for the field
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