Dissertations / Theses on the topic 'Accretion disk'
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Popham, Robert George. "Accretion disk boundary layers." Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186435.
Full textHigginbottom, Nicholas. "Modelling accretion disk winds in quasars." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/368584/.
Full textWatarai, Kenya. "Super-Critical Accretion Disk around a Black Hole." 京都大学 (Kyoto University), 2003. http://hdl.handle.net/2433/149067.
Full textKubsch, Marcus, Tobias F. Illenseer, and Wolfgang J. Duschl. "Accretion disk dynamics alpha-viscosity in self-similar self-gravitating models." EDP SCIENCES S A, 2016. http://hdl.handle.net/10150/614710.
Full textCaunt, Stuart Edward. "Analytical and numerical models of accretion disks." Thesis, University of Newcastle Upon Tyne, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265485.
Full text劉長軍 and Cheung-kwan Andy Lau. "High energy processes around the accretion disk of AGN." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1995. http://hub.hku.hk/bib/B31213236.
Full textHamper, Randall T. "Accretion disk radii changes in IP Peg during outburst." Virtual Press, 2007. http://liblink.bsu.edu/uhtbin/catkey/1371843.
Full textDepartment of Physics and Astronomy
Lau, Cheung-kwan Andy. "High energy processes around the accretion disk of AGN /." Hong Kong : University of Hong Kong, 1995. http://sunzi.lib.hku.hk/hkuto/record.jsp?B17664925.
Full textYamazaki, Tatsuya. "Two Topics on Accretion Disk Variabilities Related to Thermal Instability." 京都大学 (Kyoto University), 1997. http://hdl.handle.net/2433/202439.
Full textShah, Jay. "Understanding the origin of meteoritic magnetism : implications for protoplanetary disk accretion." Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/56625.
Full textGiustini, Margherita <1983>. "Accretion disk winds in active galactic nuclei: an X-ray view." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3892/1/giustini_margherita_tesi.pdf.
Full textGiustini, Margherita <1983>. "Accretion disk winds in active galactic nuclei: an X-ray view." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3892/.
Full textStarkey, D., Keith Horne, M. M. Fausnaugh, B. M. Peterson, M. C. Bentz, C. S. Kochanek, K. D. Denney, et al. "SPACE TELESCOPE AND OPTICAL REVERBERATION MAPPING PROJECT.VI. REVERBERATING DISK MODELS FOR NGC 5548." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/622875.
Full textPinilla, P., L. M. Pérez, S. Andrews, der Marel N. van, Dishoeck E. F. van, S. Ataiee, M. Benisty, et al. "A Multi-wavelength Analysis of Dust and Gas in the SR 24S Transition Disk." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/624044.
Full textMeng, Huan Y. A., Peter Plavchan, George H. Rieke, Ann Marie Cody, Tina Güth, John Stauffer, Kevin Covey, et al. "PHOTO-REVERBERATION MAPPING OF A PROTOPLANETARY ACCRETION DISK AROUND A T TAURI STAR." IOP PUBLISHING LTD, 2016. http://hdl.handle.net/10150/621264.
Full textBOZZO, ENRICO. "Theory and observations of neutron Star X-ray binaries: from wind to disk accretors." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2009. http://hdl.handle.net/2108/813.
Full textX-ray binaries are among the brightest X-ray sources in our Galaxy, and were the first extra-solar X-ray sources discovered in the early '60s. The first pioneristic observations of these sources were made by using rocket flights; however, in the brief interval in which rockets operated it was hard to get sufficient information to understand the nature of these sources. Only about ten years later the first generation of X-ray satellites established that most bright X-ray sources in the Galaxy are in fact binary systems containing either a neutron star (NS) or a black hole orbiting a companion star. Most of the X-ray emission of these sources is due to the accretion of matter onto the compact object. This thesis focuses on X-ray binaries hosting neutron stars. The presence of NSs in X-ray binaries is often inferred from pulsations in their X-ray flux. These occur because of the so called "lighthouse" effect, that is due to the combination of the NS rotation and misaligned intense magnetic field, which funnels the accreting matter onto the star's magnetic poles. In these sources the inferred NS magnetic fields can be as high as about 1,000 billion times that on the earth, and are thus the strongest magnetic fields known in the universe. Not all NS systems have such intense magnetic fields: in many NS X-ray binaries the field is much weaker. In these cases the flow of material onto the NS is not always channeled towards the magnetic poles and sometimes only transient pulsations are observed. Many of these low magnetic field systems also show fast quasi-periodic oscillations in their X-ray flux that originate from the interaction of the NS with the surrounding accretion disk. In some cases the accreted material (mostly hydrogen and helium) accumulating on the NS surface reaches a critical mass, at which a thermonuclear explosion takes place and the source undergoes an X-ray burst. The emission properties that characterize an accreting NS in a binary system thus depend mainly on the NS physical parameters (e.g. spin period and magnetic field strength). On the contrary, the mode in which mass transfer takes place, as well as the geometry of the accretion flow, depends on the nature of the companion star. In low mass X-ray binaries the companion star has a typical age of ~10^8 yr, and its mass is similar to or less than that of our sun. In these systems the transfer of mass takes place through the so called Roche Lobe Overflow, which usually leads to the formation of an accretion disk around the compact object. If the companion star is much younger (~few 10^6 yr) and massive (>>1 solar mass), then the system is a high mass X-ray binary, and mass transfer occurs through the wind capture by the compact star. In fact, donor stars in high mass X-ray binaries are typically blue O or B stars whose intense wind can be easily captured by the NS to release X-rays. During the past years, the operation of the present generation of X-ray satellites, such as RXTE, XMM-Newton, Chandra, Swift, and INTEGRAL, has opened a new era in the discovery and study of for X-ray binaries. This provided several breakthroughs as well as surprising new questions on these sources. In this phD thesis we consider both high and low mass NS binaries, and analyze several observational and theoretical aspects of these sources. We use data obtained with the modern X-ray telescopes available on board the present generation satellites in order to investigate the accretion processes in these sources. In particular, we study both disk and wind accretion, and compare the observational results with theoretical expectations. Some improvements in the theory of disk and wind accretion are presented. In Chapter 1 we provide a brief and comprehensive introduction on NS X-ray binaries; all other chapters are based on our original findings. We divided these chapters in two groups. In the first group (Chapters 2, 3, 4, 5, and 6), we concentrate on studies of low mass X-ray binaries. In particular, chapter 2 summarizes the magnetic threaded disk model, that is the most widely accepted model to describe the interaction between a magnetized NS and its surrounding accretion disk. By using quasi-periodic oscillations in X-ray binaries, we present a new method to test the threaded disk model against observations of slow quasi-periodic oscillations in accreting X-ray pulsars contained in high as well as low mass X-ray binaries (Bozzo, E., Stella, L., Vietri, M., et al. 2008, A&A, in press [astro-ph/0811.0049]). We also discuss some improvements on the threaded disk model that we will develop in a future publication. In Chapter 3 we propose the "recycling magnetosphere model" to explain the spin-up/spin-down behaviour of some low mass X-ray binaries that cannot be interpreted within the magnetic threaded disk scenario (Perna, R., Bozzo, E., Stella, L. 2006, ApJ, 639, 363). This model involves an in-depth analysis of the so called propeller mechanism, which is also discussed in more detail in Chapter 4 (Falanga, M., Bozzo, E., Stella, L., et al. 2007, A&A, 464, 807). Chapters 5 and 6 focus on X-ray observations of two low mass X-ray binaries, 4U 2129+47 and XTEJ1701-407. In the case of 4U 2129+47 we present the results of two XMM-Newton observations. Our analysis of these data revealed a delay of ~190 s measured across two eclipses separated by ~22 days. We show that this delay can be naturally explained as being due to the orbital motion of the binary with respect to the center of mass of a triple star and is thus probably the first X-ray signature of the triple nature of an X-ray binary (Bozzo, E., Stella, L., Papitto, A., et al. 2007, A&A, 476, 301). In the case of XTEJ1701-407 we report on the first type I X-ray burst observed from this source and discuss the results of the data analysis in the context of the modern theories of nuclear burning on the NS surface (Falanga, M., Cumming, A., Bozzo, E., et al. 2008, A&A, in press [astro-ph/0901.0314]). In the second part of this thesis (Chapters 7, 8) we concentrate on high mass X-ray binaries. In Chapter 7 we analyze in-depth the accretion process in wind-accreting binaries and apply this scenario to interpret the behaviour of a newly discovered subclass of high mass X-ray binaries, collectively termed supergiant fast X-ray transients. We suggest that these sources might host ultra-magnetized ("magnetar") NSs, and can thus provide the very first opportunity to detect and study magnetars in binary systems (Bozzo, E., Falanga, M., Stella, L. 2008, ApJ, 683, 1031). In Chapter 8 we report on an XMM-Newton observation of the supergiant fast X-ray transient IGRJ16479-4514. The timing, spectral and spatial analysis of this observation revealed a complex phenomenology that could be interpreted in terms of an eclipse by the supergiant companion, with some residual X-ray flux during the eclipse resulting from both scattering local to the source and by an interstellar dust halo along the line of sight to IGR J16479-4514 (Bozzo, E., Stella, L., Israel, G., et al. 2008, MNRAS, 391, L108). Finally, we provide a briefly outline of the possible future development in the research fields of this thesis.
MARINO, ALESSIO. "Imperfect accretion: ejecting matter in X-ray binaries." Doctoral thesis, Università degli Studi di Palermo, 2021. http://hdl.handle.net/10447/479017.
Full textKolwa, Sthabile. "The effects of environment on radio-loud AGN activity in Stripe 82." University of the Western Cape, 2016. http://hdl.handle.net/11394/5318.
Full textWe investigate the link between environment and radiative accretion efficiency using a sample of 8946 radio-loud AGN detected at 1 − 2 GHz in the SDSS Stripe 82 region. We quantify their environments using the surface-density parameter, ƩN, which measures galaxy density based on distances to Nth nearest neighbours. Comparing Ʃ2 and Ʃ5 between AGN and control galaxies, we obtain relative densities that quantify the degree of galaxy clustering around each AGN. Using this, we examine the relation between density and the HERG-LERG dichotomy (accretion-modes) classified using a 1.4 GHz luminosity (L1.4GHz) threshold. Our results indicate that, in the low-redshift interval (0.1 < z < 0.2), LERGs occupy environments denser than the field. At intermediate redshifts (0.2 < z < 1.2), both LERGs and HERGs occupy regions denser than the field. Spearman’s rank tests show that correlations between density and L1.4GHz in both redshift intervals are weak. We conclude that the absence of a strong correlation is confirmation of the idea that galaxy density plays a more secondary role on AGN activity and also, accretion-mode classification (both measured using L1.4GHz). It is likely that the rate of gas accretion or properties of galactic-scale magnetic fields correlate more strongly with L1.4GHz, hence being primarily influential.
National Research Foundation (NRF)
Takeo, Eishun. "Super-Eddington accretion onto seed black holes in the early Universe." Doctoral thesis, Kyoto University, 2020. http://hdl.handle.net/2433/253087.
Full text0048
新制・課程博士
博士(理学)
甲第22251号
理博第4565号
新制||理||1655(附属図書館)
京都大学大学院理学研究科物理学・宇宙物理学専攻
(主査)教授 嶺重 慎, 准教授 前田 啓一, 教授 長田 哲也
学位規則第4条第1項該当
Doctor of Science
Kyoto University
DFAM
Poindexter, Shawn David. "Sharpening The Tools of Gravitational Microlensing." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1258766992.
Full textKadowaki, Luis Henrique Sinki. "Reconexão magnética em discos de acreção e seus efeitos sobre a formação e aceleração de jatos: um estudo teórico-numérico." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/14/14131/tde-15012012-121521/.
Full textJets and accretion disks associated with galactic and extragalactic objects such as microquasars (i.e., stellar-mass black holes occurring in some binary stellar systems), active galactic nuclei (AGNs) and young stellar objects (YSOs), often exhibit quasi-periodic ejections of matter that may offer important clues about the physical processes that occur in their inner regions. Among these classes of objects, microquasars with transient emission in X-rays have been identified in our Galaxy since the last decade and like AGNs and distant quasars, some of them also produce collimated jets with apparent superluminal speeds, leaving no doubt that we are also dealing with ejected gas with relativistic velocities. One example widely investigated from radio wavelengths to X-rays is the microquasar GRS 1915+105 (e.g., Dhawan et al.,2000), which was the first Galactic object to show evidence of a jet with apparent superluminal motion (Mirabel e Rodríguez, 1998, 1994). A model to explain the origin of the superluminal ejections and the synchrotron radio emission in flares which are not very different from those occurring in the solar corona, was developed by de Gouveia Dal Pino e Lazarian (2005), where they invoked a process of violent magnetic reconnection between the magnetic field lines that arise from the accretion disk and the lines of the magnetosphere of the central source. In accretion episodes where the ratio between the effective disk pressure and magnetic pressure decreases to values smaller than the unity and the accretion rate approaches the critical Eddington rate, the reconnection may become violent and releases large amounts of magnetic energy in a short time. Part of this energy heats the coronal and the disk gas and part accelerates particles to relativistic velocities through a first-order Fermi-like process, which was investigated for the first time in magnetic reconnection by these authors and results a synchrotron radio power-law spectrum that is compatible to the observations. In the present work we conducted a complementary study, initiated by Piovezan (2009), which generalize the model described above for the case of AGNs. We found that the activity due to magnetic reconnection in the coronal region, at the base of the launching jet, can explain the origin of relativistic ejections from microquasars to low luminous AGNs (LLAGNs, such as Seyfert galaxies and LINERs). The power released by magnetic reconnection events as a function of the black hole masses of these sources, between 5 solar mass and 10^10 solar mass, obeys a correlation that is maintained throughout this interval, spanning 10^9 orders of magnitude. This correlation implies an almost linear dependence (in a log-log diagram), which is approximately independent of the physical properties of the accretion disks of these sources. Moreover, it is compatible with the so-called fundamental plan obtained empirically, which correlates the radio and X-rays emission of microquasars and AGNs with the masses of their black holes (see Merloni et al., 2003). Thus, the model of de Gouveia Dal Pino e Lazarian (2005) provides a simple physical interpretation for the existence of this empirical correlation as due to coronal magnetic activity in these sources. More luminous AGNs and quasars do not seem to obey the same correlation, possibly because the density around the coronal region in these sources is so high that it \"masks\" the emission due to the magnetic activity. The radio emission in these cases is possibly due regions further out of the supersonic jet, where it has already expanded enough to become optically thin and visible and where the relativistic electrons are probably accelerated in shocks (see also de Gouveia Dal Pino et al., 2010a,b). In addition, we investigated the development of magnetic reconnection events through axisymmetric magnetohydrodynamic simulations (2.5D-MHD) of the interaction between the poloidal magnetic field that arises from the viscous accretion disk (which satisfies the standard model of Shakura e Sunyaev, 1973) and the dipolar magnetosphere of the rotating central source. To this aim, we considered initial conditions which are compatible to those of YSOs. In the preliminary tests conducted here, magnetic reconnection occurs in the presence of numerical resistivity only, which is not intense enough to determine a process of reconnection with rates of the order of the Alfvén speed, i.e., it is essentially slow. Nevertheless, we were able to identify some of the effects predicted by the model of fast magnetic reconnection studied here. For example, we found that the frequency and strength with which events of magnetic reconnection can occur is sensitive to both the initial topology of the magnetic field of the system and the accretion disk rates (as predicted by the model of de Gouveia Dal Pino e Lazarian, 2005), so that such events occur more efficiently under high accretion rates. Finally, besides the investigation of the development of magnetic reconnection events, we could also examine in our numerical studies the natural formation of funnel flows which are accretion columns that transport gas from the accretion disk to the surface of the central source along the magnetic field lines. The results of these studies were compared with the observations of funnel flows in young stellar objects.
Isogai, Keisuke. "Observational Research on Dwarf Novae: Superoutburst, Evolution, and Development of a Classification Method Using Gaia DR2." Kyoto University, 2019. http://hdl.handle.net/2433/242610.
Full textTillson, Henry. "Simulations of mass accretion onto dark matter haloes and angular momentum transfer to a Milky Way disk at high redshift." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:23152d86-ca8a-42dc-9561-b31190ab75e8.
Full textCOLOMBO, Salvatore. "Radiation hydrodynamic and magnetohydrodynamic models of plasma flows accreting onto Classical T Tauri Stars." Doctoral thesis, Università degli Studi di Palermo, 2019. http://hdl.handle.net/10447/378829.
Full textContext Classical T Tauri Stars (CTTSs) are young low-mass stellar objects that accrete mass from their circumstellar disks. The disks extend internally up to the truncation radius, where the mag- netic field is strong enough to lift up the material from the disk plane and to funnel the mate- rial forming accretion columns (Koenigl 1991). The funneled plasma falls down onto the star and hits the stellar surface. The impacts generate hot shocks. CTTSs are, also, characterized by high levels of coronal activity, as revealed by X-ray observations (e.g. Favata et al. 2005). This coronal activity is mainly produced by energetic flares. Aims of this work In this work we investigated the mass accretion process in CTTSs. We studied if accretion from the disk to the star might occur as a result of a coronal activity, and we analyzed the structure and the dynamics of the accretion column plasma in the impact regions. We de- veloped numerical models that describe: a star-disk system subject to the effects of a coronal activity in proximity of the disk surface; the impact of an accretion column onto the surface of a CTTS. We investigated if an intense coronal activity due to flares that occur close to the accretion disk may perturb the stability of the inner disk, disrupt the inner part of the disk, and possi- bly trigger accretion phenomena with mass accretion rates comparable with those observed in CTTSs (Colombo et al. 2019c). To this end, we modeled a magnetized protostar surrounded by an accretion disk through 3D magnetohydrodynamics simulations. The model takes into account the gravity from the central star, the effects of viscosity in the disk, the thermal con- duction (including the effects of heat flux saturation), the radiative losses from optically thin plasma, and a parameterized heating function to trigger the flares. We explored cases charac- terized by a dipole plus an octupole stellar magnetic field configuration and by either different densities of disk or different levels of flaring activity. As it concerns the study of accretion impacts, we analyzed the effects of radiation emerg- ing from the shock-heated plasma at the base of accretion columns on the structure of the pre- shock downfalling material. To this end, we upgraded a module handling the local thermody- namic equilibrium (LTE) radiation-hydrodynamics (RHD) in the PLUTO code (Mignone et al. 2007, 2012), which we have extended to handle also the non-LTE regime (Colombo et al. 2019a). Then, we investigated if a significant absorption of radiation arising from the shock heated plasma occurs in the unshocked downfalling material, and if it leads to a pre-shock heating of the accreting gas. We developed a radiation hydrodynamics model that describes an accretion column impacting onto the surface of a CTTS (Colombo et al. 2019b). The model takes into account the stellar gravity, the thermal conduction, and the effects of both radia- tive losses and absorption of radiation by matter in non local thermodynamic equilibrium conditions. Results As it concerns the effects of flaring activity on the disk stability, we observed, as a result of the simulated intense flaring activity, the formation of several magnetic loops confining hot plasma that link the star to the disk. All these loops build up a hot extended corona with an X- ray luminosity comparable to typical values observed in CTTSs (Colombo et al. 2019c). The intense flaring activity close to the disk can strongly perturb the disk stability. The flares trig- ger overpressure waves which travel through the disk and modify its configuration. Accretion funnels may be triggered by the flaring activity, thus contributing to the mass accretion rate of the star. Accretion rates derived from the simulations range from 10−10 to 10−9M⊙yr−1 (Colombo et al. 2019c). The accretion columns can be perturbed by the flares and can interact with each other, possibly merging together in larger streams. As a result, the accretion pattern can be rather complex: the streams are highly inhomogeneous, with a complex density struc- ture, and clumped. This inhomogenity may be the origin of the variability observed in the structure of the accretion columns (Alencar et al. 2018). The non-LTE radiation module developed to study the dynamics and structure of the im- pact region of CTTSs has been validated through different tests. In particular, we modeled the structure of a radiative shock, simulating a simple shock case as described by Ensman (1994). The agreement between our solutions and the semi-analytical solutions (when available) is good, with a maximum error of 7%. Moreover, we have proven that a non-LTE approach change significantly the structure and the dynamics of the impact regions, leading to a ra- diative precursor and a greater extension of the post-shock region compared to the LTE case (Colombo et al. 2019a). Our radiative model describing the impact of an accretion column onto the stellar chro- mosphere shows that part of radiation emitted by the post-shock plasma (≈ 70%) is absorbed by the pre-shock accretion column immediately above the slab. The irradiation heats the downfalling unshocked material up to ≈ 105K. This hot material forms a precursor region that emits in the UV band. The results of this PhD project may address some open questions regarding CTTSs. For instance, we proved that an intense flaring activity in proximity of the disk may perturb its stability and may generate accretion columns highly structured in density and characterized by clumps as recently observed, for example, by Alencar et al. (2018). Moreover, with our radiation model we may naturally explain the origin of the complex UV spectra arising from impact regions (Ardila et al. 2013) and the fact that accretion rates derived from UV observations are systematically higher than rates inferred from X-ray ob- servations (Curran et al. 2011). In fact, our model predicts the presence of a precursor region emitting in the UV. This region: 1) would increase the UV flux arising from the impact with- out assuming higher accretion rates and 2) may generate an UV flux produced by plasma at free fall velocity, thus with Doppler shifts stronger than those generated by the post-shock plasma. This may explain the high redshifts and broadening observed in emission lines of UV spectra (Ardila et al. 2013).
CALDERONE, GIORGIO. "The big blue bump-accretion disk connection in type1 active galactic nuclei: a new way to estimate the mass of super-massive black hole." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2013. http://hdl.handle.net/10281/43720.
Full textKlein, Fabian [Verfasser], and Rainer [Akademischer Betreuer] Spurzem. "Simulations of an accretion disk surrounding a supermassive black hole and its interaction with a nuclear star cluster / Fabian Klein ; Betreuer: Rainer Spurzem." Heidelberg : Universitätsbibliothek Heidelberg, 2018. http://d-nb.info/1177149672/34.
Full textMudd, Dale Montaine. "Understanding Supermassive Black Holes Using the Dark Energy Survey and OzDES." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1500305577021114.
Full textFedele, Davide. "Structure and Evolution of Protoplanetary Disks." Doctoral thesis, Università degli studi di Padova, 2008. http://hdl.handle.net/11577/3427197.
Full textSiregar, Edouard. "Etude de la stabilite des disques d'accretion en astrophysique." Toulouse 3, 1987. http://www.theses.fr/1987TOU30268.
Full textWafflard-Fernandez, Gaylor. "Signatures observationnelles de la migration planétaire dans l'émission des poussières froides des disques protoplanétaires." Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30250.
Full textThe subject of this PhD thesis is related to the orbital evolution of planets in a protoplanetary disk made of gas and dust around a young star (the first ten million years after the star's formation). The gravitational interaction between planets and the protoplanetary disk gas rapidly changes the distance between the planets and the star. This is known as planetary migration. Many studies have examined how the direction and speed of planetary migration depend on the planet's mass and the physical properties of the disk gas, with the aim to explain the orbital properties of exoplanets. Dust is most often discarded in this kind of studies because its mass content is much smaller than that of the gas and it should therefore have a negligible impact on planetary migration. Yet, dust has gained considerable importance over the past few years owing to the rapidly growing number of multi-wavelength spatially resolved observations of the dust emission in protoplanetary disks. These observations show that dust emission, in particular the cold dust emission at radio wavelengths such as that probed by the ALMA interferometer, can feature structures (spirals, rings and gaps, crescent-shaped asymmetries...) that are very similar to those imparted by disk-planets interactions. For this reason, structures in the dust emission are often interpreted as signatures of the presence of hidden planets. These structures therefore stress the need to better understand how disk-planets interactions generally, and planetary migration more specifically, impact the dust emission in protoplanetary disks. This is the aim of my PhD thesis. To reach this goal, I have carried out 2D and 3D hydrodynamical simulations modeling both the dust and gas of a protoplanetary disk where one or several planets form and migrate. The simulations results have been post-processed by dust and line radiative transfer calculations to compute synthetic maps of the disk emission that are directly comparable to observations. I show that the large-scale intermittent migration towards its star of a planet with a mass typically between those of Saturn and Jupiter is able to generate multiple rings of millimeter dust particles. These annular structures in the dust distribution take the form of bright and dark rings in the radio emission that resemble those observed in several disks. The intensity contrast between bright and dark rings is detectable with ALMA's current sensitivity. Other aspects explored in this thesis include the kinematic signatures of the presence of a massive planet in the gas emission of its disk, and the dust emission at the Lagrange points of a migrating planet
Meglicki, Zdzislaw, and Zdzislaw Meglicki [gustav@perth ovpit indiana edu]. "Analysis and Applications of Smoothed Particle Magnetohydrodynamics." The Australian National University. Research School of Physical Sciences, 1995. http://thesis.anu.edu.au./public/adt-ANU20080901.114053.
Full textBezayiff, Nate. "Mass estimate of black hole candidates GRS 1758-258 and GX 339-4 based on a transtion layer model of the accretion disk and a search for X-ray jets in GRS 1758-258 /." Diss., Digital Dissertations Database. Restricted to UC campuses, 2006. http://uclibs.org/PID/11984.
Full textSchreiber, Matthias. "Disc accretion onto white dwarfs." Doctoral thesis, [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=961356944.
Full textSavcheva, Antonia Stefanova. "Magnetically torqued thin accretion disks." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/36119.
Full textIncludes bibliographical references (leaves 61-64).
We consider geometrically thin accretion disks around millisecond X-ray pulsars. We start with the Shakura-Sunyaev thin disk model as a basis and modify the disk equations with a magnetic torque from the central neutron star. Disk solutions are computed for a range of neutron star magnetic fields. We also investigate the effect of different equations of state and opacities on the disk solutions. We show that there are indications of thermal instability in some of the disk solutions, especially for the higher values of 3M. We also explain how the time evolution of the disk solutions can be calculated.
by Antonia Stefanova Savcheva.
S.B.
Gu, Pin-gao. "Turbulence in Keplerian accretion disks /." Digital version accessible at:, 2000. http://wwwlib.umi.com/cr/utexas/main.
Full textTrova, Audrey. "Gravité des systèmes verticalement homogènes : applications aux disques astrophysiques." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00955555.
Full textIsaacs, Sonja [Verfasser]. "Unveiling Accretion Disks - Physical Parameter Eclipse Mapping of Accretion Disks in Dwarf Novae / Sonja Isaacs." München : GRIN Verlag, 2002. http://d-nb.info/1177524554/34.
Full textForveille, Thierry. "Observations millimétriques de matière circumstellaire autour d'objets jeunes et d'étoiles évoluées : [thèse soutenue sur un ensemble de travaux]." Grenoble 1, 1988. http://www.theses.fr/1988GRE10045.
Full textEGRON, ELISE MARIE JEANNE. "Spectral Comparisons of Neutron Star Low-Mass X-Ray Binaries with Black Hole X-Ray Binaries." Doctoral thesis, Università degli Studi di Cagliari, 2013. http://hdl.handle.net/11584/266223.
Full textKalari, Venu Madhav. "Disc-accretion in star-forming regions." Thesis, Queen's University Belfast, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.695381.
Full textCurran, Dian Beard. "Magnetic shearing instabilities in accretion disks /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
Full textKlee, J., T. F. Illenseer, M. Jung, and W. J. Duschl. "The impact of numerical oversteepening on the fragmentation boundary in self-gravitating disks." EDP SCIENCES S A, 2017. http://hdl.handle.net/10150/625972.
Full textSimon, M. N., I. Pascucci, S. Edwards, W. Feng, U. Gorti, D. Hollenbach, E. Rigliaco, and J. T. Keane. "TRACING SLOW WINDS FROM T TAURI STARS VIA LOW-VELOCITY FORBIDDEN LINE EMISSION." IOP PUBLISHING LTD, 2016. http://hdl.handle.net/10150/622166.
Full textArmitage, Philip J., Josh A. Eisner, and Jacob B. Simon. "PROMPT PLANETESIMAL FORMATION BEYOND THE SNOW LINE." IOP PUBLISHING LTD, 2016. http://hdl.handle.net/10150/621505.
Full textČemeljić, Miljenko. "Resistive magnetohydrodynamic jets from protostellar accretion disks." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=974114529.
Full textCemeljic, Miljenko. "Resistive magnetohydrodynamic jets from protostellar accretion disks." Phd thesis, Universität Potsdam, 2005. http://opus.kobv.de/ubp/volltexte/2005/209/.
Full textIn this thesis the magnetohydrodynamic jet formation and the effects of magnetic diffusion on the formation of axisymmetric protostellar jets have been investigated in three different simulation sets. The time-dependent numerical simulations have been performed, using the magnetohydrodynamic ZEUS-3D code.
Wynn, Rebecca. "Accretion disc instabilities in cataclysmic variable stars." Thesis, University of Leicester, 2000. http://hdl.handle.net/2381/30642.
Full textNayakshin, Sergei Victor 1969. "Physics of accretion disks with magnetic flares." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/288916.
Full textLin, Min-Kai, and Andrew N. Youdin. "A Thermodynamic View of Dusty Protoplanetary Disks." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/626177.
Full textBlank, M., M. R. Morris, A. Frank, J. J. Carroll-Nellenback, and W. J. Duschl. "The inner cavity of the circumnuclear disc." OXFORD UNIV PRESS, 2016. http://hdl.handle.net/10150/617417.
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