The tidal disruption of stars by a massive black hole at the center of a galaxy.

Persistent Link:
http://hdl.handle.net/10150/187412
Title:
The tidal disruption of stars by a massive black hole at the center of a galaxy.
Author:
Fulbright, Michael Scott.
Issue Date:
1995
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Studies of the luminosity evolution of optical Quasi-Stellar Objects (QSOs) suggest that a large number of normal-looking galaxies today have a central massive black hole. These galaxies once contained Active Galactic Nuclei (AGN), but a dwindling fuel supply forced the central engine to fade. If one of these galaxies happens to be close enough, it might be possible to detect the central black hole by the effects it has on the kinematics and surface density of stars in the galactic nucleus. But, for the majority of galaxies, it is not feasible to observe these effects due to their great distance. Not feasible, that is, until the black hole disrupts a passing star. The debris of the star will form an accretion disk around the black hole. The galactic nucleus will then become a reborn AGN. It is then possible to detect the black hole by the sudden appearance of a compact source of extreme UV and X-ray photons at the center of a galaxy. Broad, double-peaked emission lines may also appear, giving conclusive evidence that an accretion disk has formed around a massive black hole. A survey to detect flares from galactic nuclei resulting from tidally-disrupted stars could possibly answer whether or not most galaxies go through an AGN phase. In this work, we will use Smoothed Particle Hydrodynamics (SPH) simulations to remove much of the uncertainty that existed in previous work on the tidal disruption of stars. These works were forced to assume that stars which passed inside the Roche limit of a black hole were completely accreted by the black hole. We will replace this assumption with the results of our SPH simulations, and find that previous works overestimated the rate at which gas is stripped from stars by a factor of two. We will then review the observational consequences of a disruption event, and consider two cases in which such an event may have been witnessed.
Type:
text; Dissertation-Reproduction (electronic)
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Astronomy; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
Benz, Willy

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleThe tidal disruption of stars by a massive black hole at the center of a galaxy.en_US
dc.creatorFulbright, Michael Scott.en_US
dc.contributor.authorFulbright, Michael Scott.en_US
dc.date.issued1995en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractStudies of the luminosity evolution of optical Quasi-Stellar Objects (QSOs) suggest that a large number of normal-looking galaxies today have a central massive black hole. These galaxies once contained Active Galactic Nuclei (AGN), but a dwindling fuel supply forced the central engine to fade. If one of these galaxies happens to be close enough, it might be possible to detect the central black hole by the effects it has on the kinematics and surface density of stars in the galactic nucleus. But, for the majority of galaxies, it is not feasible to observe these effects due to their great distance. Not feasible, that is, until the black hole disrupts a passing star. The debris of the star will form an accretion disk around the black hole. The galactic nucleus will then become a reborn AGN. It is then possible to detect the black hole by the sudden appearance of a compact source of extreme UV and X-ray photons at the center of a galaxy. Broad, double-peaked emission lines may also appear, giving conclusive evidence that an accretion disk has formed around a massive black hole. A survey to detect flares from galactic nuclei resulting from tidally-disrupted stars could possibly answer whether or not most galaxies go through an AGN phase. In this work, we will use Smoothed Particle Hydrodynamics (SPH) simulations to remove much of the uncertainty that existed in previous work on the tidal disruption of stars. These works were forced to assume that stars which passed inside the Roche limit of a black hole were completely accreted by the black hole. We will replace this assumption with the results of our SPH simulations, and find that previous works overestimated the rate at which gas is stripped from stars by a factor of two. We will then review the observational consequences of a disruption event, and consider two cases in which such an event may have been witnessed.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineAstronomyen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.chairBenz, Willyen_US
dc.contributor.committeememberShields, Josephen_US
dc.contributor.committeememberBurrows, Adamen_US
dc.contributor.committeememberLiebert, James W.en_US
dc.identifier.proquest9622987en_US
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