Дисертації з теми "Galactic Outflow"
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McGraw, Sean Michael. "Outflow and Accretion Physics in Active Galactic Nuclei." Ohio University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1469701247.
Повний текст джерелаEdmonds, Bartlett D. "On the Distances and Energetics of AGN Outflows." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/23767.
Повний текст джерелаPh. D.
Moss, Vanessa. "The Galactic ecosystem: Outflow and infall in the halo of the Milky Way." Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/13488.
Повний текст джерелаBallone, Alessandro [Verfasser], and Andreas [Akademischer Betreuer] Burkert. "Hydrodynamical simulations of the Galactic Center cloud G2 as an outflow / Alessandro Ballone ; Betreuer: Andreas Burkert." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2016. http://d-nb.info/1148276564/34.
Повний текст джерелаXu, Xinfeng. "How Do Quasars Impact Their Host Galaxies? From the Studies of Quasar Outflows in Absorption and Emission." Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/98572.
Повний текст джерелаDoctor of Philosophy
Super massive black holes (SMBHs) are believed to exist in the center of almost all massive galaxies, where the brightest accreting ones are named ``quasars''. ``Quasar-mode feedback'' occurs when momentum and energy from the environment of accreting SMBHs couple to the host galaxy. One mechanism for such a coupling is by high-velocity (up to $sim$ 0.2c) quasar-driven ionized outflows, appearing as blue-shifted absorption and emission lines in quasar spectra. Given enough energy and momentum, these outflows are capable of affecting the evolution of their host galaxies. Such quasar outflows are invoked to explain a variety of observations, e.g., the chemical enrichment of the intergalactic medium (IGM), the shape of the observed quasar luminosity function, and the self-regulation of the growth of the SMBHs. In this dissertation, I focus on studying the emission and absorption outflows observed in quasars spectra, collected with the largest telescopes and most powerful instruments in the world. (1). By conducting large broad absorption line (BAL) quasar surveys in both Sloan Digital Sky Survey and Very Large Telescopes (VLT), we determined various physics properties of quasar absorption outflows, e.g., the electron number density (ne), the distance of outflows to the central quasar ($R$), and the kinetic energy carried by the outflow ($dot{E}_{k}$). We demonstrated that half of the typical BAL outflows are situated at $R$ $>$ 100 pc, i.e., having the potential to affect the host galaxies. (2). Our group carried out a Hubble Space Telescope program (PI: Arav) for studying the outflows in the Extreme-UV, collaborating with Dr. Gerard Kriss from Space Telescope Science Institute (STScI). We developed a novel method to fit the multitude of quasar absorption troughs efficiently and accurately. We have identified the most energetic quasar-driven outflows on record and discovered the largest acceleration and velocity-shift for a quasar absorption outflow. (3). By using the VLT data, Xu led the project to study the relationships between BAL outflows and emission line outflows. We found possible connections between these two types of quasar outflows, e.g., the luminosity of the [oiii] ly 5007 emission profile decreases with increasing ne derived from the BAL outflow in the same quasar. These findings are consistent with BAL and emission outflows being different manifestations of the same wind, and the observed relationships are likely a reflection of the outflow density distribution.
Jeffrey, Robert. "The remarkable outflows from the galactic microquasar SS433." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:b9f5657b-a122-464f-8c55-db349ba74c4c.
Повний текст джерелаCirasuolo, Michele. "AGN outflows and galaxy formation." Doctoral thesis, SISSA, 2004. http://hdl.handle.net/20.500.11767/4168.
Повний текст джерелаNakashima, Shinya. "X-RAY STUDY ON PLASMA OUTFLOWS FROM THE GALACTIC CENTER." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/188484.
Повний текст джерелаMehdipour, M. "Ionised outflows and multi-wavelength variability of Active Galactic Nuclei." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1379538/.
Повний текст джерелаFields, Dale L. "Absorption-line measurements of AGN outflows." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1155913695.
Повний текст джерелаGlasow, Wolfgang von [Verfasser], and Martin [Akademischer Betreuer] Krause. "Simulating galactic winds with the NIRVANA grid code : how to launch galactic outflows / Wolfgang von Glasow. Betreuer: Martin Krause." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2012. http://d-nb.info/1026211182/34.
Повний текст джерелаFischer, Travis C. "Determining Inclinations of Active Galactic Nuclei via their Narrow-Line Region Kinematics." Digital Archive @ GSU, 2012. http://digitalarchive.gsu.edu/phy_astr_diss/56.
Повний текст джерелаCoatman, Liam. "A near-infrared view of luminous quasars : black hole masses, outflows and hot dust." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/269406.
Повний текст джерелаGiarrusso, Daniele. "Properties of the galactic-scale gas circulation generated by stellar feedback." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20942/.
Повний текст джерелаRoos, Orianne. "Modelling feedback processes, star formation and outflows in high-redshift galaxies." Thesis, Sorbonne Paris Cité, 2016. http://www.theses.fr/2016USPCC148/document.
Повний текст джерелаIn the Universe, we observe galaxies forming no, or almost no, stars anymore, but astrophysicists do not know yet what physical mechanisms cause their “death”. To give clues to solve the problem, I studied feedback processes from stars and active supermassive black holes, star formation and galactic outflows. Chapter 1 presents all the notions to understand the problem: the characteristics of typical galaxies in the local and distant Universe, galactic outflows, galaxy death, active supermassive black holes, stars, and their feedback processes. In Chapter 2, I describe the numerical techniques I used: the simulation code RAMSES, and the radiative transfer code Cloudy, which I used to develop a computation method to get the ionization state of an entire galaxy. This method is presented in Chapter 3. Chapter 4 studies the coupling between the feedback processes of active supermassive black holes and stars, with the POGO project, Physical Origins of Galactic Outflows. During this thesis, I showed that typical active supermassive black hole cannot suddenly kill their host, even when stellar feedback processes are accounted for, and that their coupling either reduces or enhances the mass outflow rate depending on the mass of the host. In Chapter 5, I give a state-of-the-art about active supermassive black holes before and during my thesis, sum up the conclusions of the work, and give perspectives to enlarge the scope of the study, especially regarding the additional role of cosmic rays in the death of galaxies
Chung, Andrew S. [Verfasser], and Simon D. M. [Akademischer Betreuer] White. "The long and winding road: lyman-alpha radiative transfer and galactic outflows / Andrew S. Chung. Betreuer: Simon D. M. White." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2016. http://d-nb.info/1106098498/34.
Повний текст джерелаSpitoni, Emanuele. "The effects of galactic fountains on the chemical evolution of galaxies." Doctoral thesis, Università degli studi di Trieste, 2010. http://hdl.handle.net/10077/3435.
Повний текст джерелаIn this thesis we study the effect of galactic fountains, namely gas and flows from the disk of galaxies produced by multiple supernova explosions, on the chemical evolution of galaxies. Sequential supernova explosions create a superbubble, whereas the swept up interstellar medium is concentrated in a supershell which can break out a stratified medium, producing bipolar outflows. The gas of the supershells can fragment into clouds which eventually fall toward the disk producing so-called galactic fountains. Many works in literature have dealt with superbubble expansion in stratified media. However, very few papers in the past have taken into account the chemical evolution of the superbubble and how the supershell get polluted from the metals produced by supernova explosions. With this thesis for the first time the effect of galactic fountains we consider in a detailed chemical evolution model for the Milky Way. In the first part of our work we study the expansion law and chemical enrichment of a supershell powered by the energetic feedback of a typical Galactic OB association at various galactocentric radii. We follow the orbits of the fragments created when the supershell breaks out and we compare their kinetic and chemical properties with the available observations of high - and intermediate - velocity clouds. We use the Kompaneets (1960) approximation for the evolution of the superbubble driven by sequential supernova explosions and we compute the abundances of oxygen and iron residing in the thin cold supershell. Due to Rayleigh-Taylor instabilities we assume that supershells are fragmented and we follow the orbit of the clouds either ballistically or by means of a hybrid model considering viscous interaction between the clouds and the extra-planar gas. We find that if the initial metallicity is solar, the pollution from the dying stars of the OB association has a negligible effect on the chemical composition of the clouds. The maximum height reached by the clouds above the plane seldom exceeds 2 kpc and when averaging over different throwing angles, the landing coordinate differs from the throwing coordinate by only 1 kpc. Therefore, it is unlikely that galactic fountains can affect abundance gradients on large scales. The range of heights and [O/Fe] ratios spanned by our clouds suggest that the high velocity clouds cannot have a Galactic origin, whereas intermediate velocity clouds have kinematic properties similar to our predicted clouds but have observed overabundances of the [O/Fe] ratios that can be reproduced only with initial metallicities which are too low compared to those of the Galaxy disk. Even if it is unlikely that galactic fountains can affect abundance gradients on large scales, they can still affect the chemical enrichment of the interstellar medium (ISM) because of the time-delay due to the non-negligible time taken by fountains to orbit around and fall back into the Galaxy. This implies a delay in the mixing of metals in ISM which conflicts with the instantaneous mixing approximation usually assumed in all models in literature. We test whether relaxing this approximation in a detailed chemical evolution model can improve or worsen the agreement with observations. To do that, we investigate two possible causes for relaxing of the instantaneous mixing: i) the ``galactic fountain time delay effect'' and ii) the ``metal cooling time delay effect''. We find that the effect of galactic fountains is negligible if an average time delay of 0.1 Gyr, as suggested by our model, is assumed. Longer time delays produce differences in the results but they are not realistic. The metal cooling time delays produce strong effects on the evolution of the chemical abundances only if we adopt stellar yields depending on metallicity. If, instead, the yields computed for the solar chemical composition are adopted, negligible effects are produced, as in the case of the galactic fountain delay. The relaxation of the IMA by means of the galactic fountain model, where the delay is considered only for massive stars and only in the disk, does not affect the chemical evolution results. The combination of metal dependent yields and time delay in the chemical enrichment from all stars starting from the halo phase, instead, produces results at variance with observations.
XXII Ciclo
1979
Nony, Thomas. "Formation d'étoiles massives en amas : conditions initiales, origine des masses stellaires et éjections protostellaires The unexpectedly large proportion of high-mass star-forming cores in a Galactic mini-starburst Detection of a high-mass prestellar core candidate in W43-MM1 Episodic accretion constrained by a rich cluster of outflows Molecular analysis of a high-mass prestellar core candidate in W43-MM1." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAY054.
Повний текст джерелаThe research I have performed during my PhD addresses three major challenges of the star formation field: constraining, observationally, the earliest phases of high-mass star formation – the so-called prestellar stage, studying the origin of the stellar masses, and characterizing the process of protostellar accretion-ejection.Going beyond the current paradigms of star formation requires studying star-forming regions which are more representative of the general mode of star formation in the Milky Way. To this purpose I have used ALMA observations of W43-MM1, a young located at 5.5 kpc distance from the Sun, which presents a high star formation rate. The first step of my work has been to identify and characterize cores in the continuum image. I discovered 131 cores about 2400 AU in size which have mass between 1 and 100 Msun. I measured their mass distribution (CMF) and found a slope of -0.96 +/- 0.13 on 1.6 - 100 Msun that is markedly flatter than the reference Salpeter slope of the IMF on that range, -1.35. This means an overabundance of high-mass cores - and thus high-mass stars -compared to the number expected by the current models of star formation. Possible explanations imply either that star-formation is atypical in W43-MM1 (variably in the Milky Way) or that high-mass stars form at different time than low-mass stars in a cluster (star formation would not be a continuous process).I have characterized these cores using CO(2-1) and SiO(5-4) lines and revealed a rich cluster of 45 outflow lobes from 27 cores covering the whole mass range and including 11 high-mass cores (M>16 Msun). I have also used the detection of Complex Organic Molecules (COMs), typically detected in warm environments like hot cores, as indicator of the protostellar activity. 12 out of the 13 high-mass cores in W43-MM1 have eventually been characterized as protostellar, leaving one good high-mass prestellar core candidate. These statistics raises question about the universality of a prestellar phase for high-mass stars and suggests that the core-fed models for high-mass star formation cannot generally apply. The protostellar outflows also bring valuable information on the accretion/ejection history. I have studied the kinematics of high-velocity molecular jets that divide into knots using Position-Velocity diagrams. I have shown that the complex velocity structures of these knots hide a strong variability, and evaluated the associated timescale between two ejections to be about 500 yr. This is reminiscent of the values obtained between accretion burst in FU Orionis stars
Hsieh, Pei-Ying, and 謝佩穎. "The Inflow and Outflow in the Galactic Centers." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/psyyw6.
Повний текст джерела國立中央大學
天文研究所
103
In this thesis I present studies of the kinematics and the physical properties of molecular gas galactic nuclei. Two representative bar galaxies; (1) NGC 1097, (2) our own Galactic center, are studied. The nucleus of NGC 1097 consists of a molecular concentration, ~350 pc in scale, and a starburst ring, ~kpc in scale. To better depict the kinematics and the star formation of the nucleus, the SubmilliMeter Array (SMA) and the Hubble Space Telescope (HST) are used to obtain high angular resolution CO(J = 2-1) line and the Pa_alpha line images. The unprecedented high resolution reveals that the turbulent/diffuse molecular gas (V ~90 km/s) is associated with the dust lane. The less turbulent/dense molecular gas (V ~45 km/s) could be determined to be associated with the starburst ring. The variations of the physical properties of the molecular gas are associated with the large scale dynamics. However, the star formation rate is not significantly affected by such dynamics. For similar type of galaxies, this work initiated the quantitative measurements of the evolution of star formation in the kilo-parsec starburst ring. The high-J dense gas in the nuclear region of NGC 1097 are investigated with the HCN(J = 3-2) and HCO+(J = 3-2) lines observed by SMA. The purpose is to resolve and study the enhancement of the HCN abundance in the vicinity of the Seyfert 1 nucleus. In the nuclear concentration of NGC 1097, the HCN(J = 3-2) line is found to contribute 30% to the total HCN(J = 3-2) line flux. A self-consistent check of the fractional abundance enhanced by X-ray ionization chemistry of the nucleus is possible with our observation, and the results are consistent with the X-ray chemical model. In addition, the HCN(J = 3-2) and HCO+(J = 3-2) emission lines are optically thin and they show tight intensity correlation with the Spitzer 24 micron-meter emission in the starburst ring. The CO(J = 3-2) line is optically thick and shows poor correlation with the 24 micron-meter emission. This suggests that the dense molecular gas and the dust are of the same origins: the star-forming region hundred-pc scale. Next studies on the Galactic Cener (GC) are presented. I obtained the first CS(J = 4-3) and CS(J = 5-4) maps of GC with the Caltech Submillimeter Observatory (CSO). The main purpose is to study the polar arc, which is a molecular ridge near the SgrA region, with apparent non-coplanar motions and acceleration perpendicular to the Galactic disk. With the new high-J CS maps, a new component in the ridge smoothly connecting the Polar Arc and the Galactic disk is found. This new component is the brightest in the CS(J = 4-3) line. The physical conditions of this new component can be determined using the rotational diagrams and the statistical equilibrium calculation. I found the physical conditions (density, temperature) to produce highest opacity of this new component in the CS(J = 4-3) line. This suggests that this new component is intrinsically the brightest in the CS(J = 4–3) line. I also lead a project to map the entire central molecular zone (CMZ) of the GC with the CS(J = 2-1) line using the Nobeyama 45m telescope. I present the early results of the central 30 pc of the CMZ in the last part of this thesis. With the low velocity molecular gas surrounding the 20 cm radio halo, I identify a possible expanding shell with a size of ~30 pc near the SgrA complex. In addition, a possible outflow expanding/accelerating perpendicular to the Galactic plane cloud be found. The time scales of these features are 100000 years, which can not be driven by the Galactic center supernova SgrA East (~10000 years). This large scale outflow could be produced by >8 supernova explosions 100000 years ago.
Chang, Yi-Wen, and 張逸雯. "A numerical simulation survey on the outflow from the Galactic center." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/45157849101064455868.
Повний текст джерела國立中央大學
天文研究所
101
In the second half of 2010, Fermi satellite discovered two giant gamma ray bubbles above and below our Galactic plane in the direction of the Galactic center. The bubbles extended 50 degrees in Galactic latitude and 40 degrees in longitude. The spatial distributions correlated with the ROSAT X-ray map at 1.5 keV and the WMAP haze near the Galactic plane. Among many possible origins of the bubbles, we are particular interested in the scenario that stars are repeatedly captured by the supermassive black hole located at the Galactic center. At each capture, a huge amount of energy is release and causes a massive expansion or outflow that forms the bubbles. We adopt the astro-hydrodynamic code PLUTO to study this phenomenon. We carry out 2D (cylindrical coordinates) numerical survey on the formation and evolution of the bubbles under different conditions, such as different energy release at each capture and different time intervals between captures. We also consider the effect of different assumed scale heights of the Galactic gaseous disk. When we compare different single capture cases (with same scale height), we learn that the shape of the bubble from small energy release is rounder and extended further in the lateral direction than the one from large energy release, but the perturbation is weaker. When the energy release is large, the bubble can easily penetrate the disk, but the lateral extend is restricted to about three times the scale heights. The morphology of a single capture case and a repeated captures case with the same total energy is significantly different. The repeated captures case has lesser lateral evolution and a lot more turbulent interior. Moreover, the turbulent level increases when the interval between captures decreases. The X-ray maps from simulations show that the repeated captures cases have slightly thick lower bubble edge than the single capture cases. We also compare the maps with ROSAT data.
Sarkar, Kartick Chandra. "Fermi Bubbles and Galactic Outflows in Circumgalactic Medium." Thesis, 2017. http://etd.iisc.ac.in/handle/2005/4225.
Повний текст джерелаSERAFINELLI, ROBERTO. "X-ray spectral variability of Active Galactic Nuclei from XMM-Newton data." Doctoral thesis, 2018. http://hdl.handle.net/11573/1080453.
Повний текст джерелаVijayan, Aditi. "Understanding Multi-Wavelength Signatures of Galactic Outflows Through 3-D Simulations." Thesis, 2020. https://etd.iisc.ac.in/handle/2005/4539.
Повний текст джерелаEverett, John Eric. "Two-phase models of disk driven outflows in active galactic nuclei with combined hydromagnetic and radiative driving /." 2003. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3097103.
Повний текст джерелаKirkpatrick, Charles. "The Relationship Between Active Galactic Nuclei and Metal-enriched Outflows in Galaxy Clusters." Thesis, 2012. http://hdl.handle.net/10012/6529.
Повний текст джерелаVenturi, Giacomo. "The impact of galactic outflows on their host galaxies through spatially resolved spectroscopy." Doctoral thesis, 2019. http://hdl.handle.net/2158/1160629.
Повний текст джерелаMerello, Ferrada Manuel Antonio. "Study of galactic clumps with millimeter / submillimeter continuum and molecular emission : early stages of massive star formation." Thesis, 2014. http://hdl.handle.net/2152/26868.
Повний текст джерелаtext
Coudé, Simon. "Étude sous-millimétrique de l’interaction entre le magnétisme et la turbulence dans les milieux interstellaires." Thèse, 2017. http://hdl.handle.net/1866/20601.
Повний текст джерела