Matching Items (7)
Filtering by

Clear all filters

135330-Thumbnail Image.png

Numerical Simulation of Jet-Induced Star Formation

ContributorsPowell, Devon (Author) / Gardner, Carl (Thesis director) / Scannapieco, Evan (Committee member) / Windhorst, Rogier (Committee member) / Barrett, The Honors College (Contributor)
Created2012-05
135817-Thumbnail Image.png

WENO Simulations of the Fermi Bubbles Emitted by Our Galaxy

Description
In 2010, two gamma-ray /x-ray bubbles were detected in the center of the Milky Way Galaxy. These bubbles extend symmetrically ≈ 30, 000 light years above and below the Galactic Center, with a width of ≈ 27, 000 light years. These bubbles emit gamma-rays at energies between 1 and 100…

In 2010, two gamma-ray /x-ray bubbles were detected in the center of the Milky Way Galaxy. These bubbles extend symmetrically ≈ 30, 000 light years above and below the Galactic Center, with a width of ≈ 27, 000 light years. These bubbles emit gamma-rays at energies between 1 and 100 giga-electronvolts, have approximately uniform surface brightness, and are expanding at ≈ 30, 000 km/s. We believe that these Fermi Bubbles are the result of an astrophysical jet pulse that occurred millions of years ago. Utilizing high-performance computing and Euler’s Gas Dynamics Equations, we hope to find a realistic simulation that will tell us more about the age of these Fermi Bubbles and better understand the mechanism that powers the bubbles.
ContributorsWagner, Benjamin Leng (Author) / Gardner, Carl (Thesis director) / Jones, Jeremiah (Committee member) / Computing and Informatics Program (Contributor) / Department of Information Systems (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
136412-Thumbnail Image.png

WENO Simulations of AGN-jet Induced Star Formation

Description
This project discusses simulation results of star formation by Active Galactic Nuclei (AGN) jets using the WENO method. A typical AGN jet with velocity uj=0.3c, density ρj=10^(-2) H/cm3, and temperature Tj=10^(7) K was injected into a 425 light years square region. The jet passes through a stationary inhomogeneous ambient background…

This project discusses simulation results of star formation by Active Galactic Nuclei (AGN) jets using the WENO method. A typical AGN jet with velocity uj=0.3c, density ρj=10^(-2) H/cm3, and temperature Tj=10^(7) K was injected into a 425 light years square region. The jet passes through a stationary inhomogeneous ambient background of temperature Ta=5x10^4 K and density ρa= 2 H/cm^3 to test if AGN jets, by creating bow shocks propagating through the interstellar medium and molecular clouds, can form stars in the densest regions. According to the star formation criteria for gravitational collapse of Cen and Ostriker, the resulting simulations indicate the presence of star formation via AGN jets (1992). The parameters are tuned to match Centaurs A to identify star formation in this galaxy. The simulations will also be run in three dimensions in the future and for longer time intervals to gain a better understanding of the star formation process via AGN jets.
ContributorsFindley, Christina Marie (Author) / Gardner, Carl (Thesis director) / Scannapieco, Evan (Committee member) / Barrett, The Honors College (Contributor) / School of Earth and Space Exploration (Contributor) / School of Mathematical and Statistical Sciences (Contributor)
Created2015-05
134898-Thumbnail Image.png

Numerical Simulation of the Surface Brightness of Astrophysical Jets

Description
The goal of this thesis is to extend the astrophysical jet model created by Dr.
Gardner and Dr. Jones to model the surface brightness of astrophysical jets. We attempt to accomplish this goal by modeling the astrophysical jet HH30 in the spectral emission lines [SII] 6716Å, [OI] 6300Å, and [NII] 6583Å.…

The goal of this thesis is to extend the astrophysical jet model created by Dr.
Gardner and Dr. Jones to model the surface brightness of astrophysical jets. We attempt to accomplish this goal by modeling the astrophysical jet HH30 in the spectral emission lines [SII] 6716Å, [OI] 6300Å, and [NII] 6583Å. In order to do so, we used the jet model to simulate the temperature and density of the jet to match observational data by Hartigan and Morse (2007). From these results, we derived the emissivities in these emission lines using Cloudy by Ferland et al. (2013). Then we used the emissivities to determine the surface brightness of the jet in these lines. We found that the simulated surface brightness agreed with the observational surface brightness and we conclude that the model could successfully be extended to model the surface brightness of a jet.
ContributorsVargas, Perry Bialek (Author) / Gardner, Carl (Thesis director) / Scannapieco, Evan (Committee member) / School of Mathematical and Statistical Sciences (Contributor) / School of Earth and Space Exploration (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
148230-Thumbnail Image.png

The Effect of Varying Mass Loss Rate on the Initial-Final Mass Relation of Massive Stars

Description

Stellar mass loss has a high impact on the overall evolution of a star. The amount<br/>of mass lost during a star’s lifetime dictates which remnant will be left behind and how<br/>the circumstellar environment will be affected. Several rates of mass loss have been<br/>proposed for use in stellar evolution codes, yielding…

Stellar mass loss has a high impact on the overall evolution of a star. The amount<br/>of mass lost during a star’s lifetime dictates which remnant will be left behind and how<br/>the circumstellar environment will be affected. Several rates of mass loss have been<br/>proposed for use in stellar evolution codes, yielding discrepant results from codes using<br/>different rates. In this paper, I compare the effect of varying the mass loss rate in the<br/>stellar evolution code TYCHO on the initial-final mass relation. I computed four sets of<br/>models with varying mass loss rates and metallicities. Due to a large number of models<br/>reaching the luminous blue variable stage, only the two lower metallicity groups were<br/>considered. Their mass loss was analyzed using Python. Luminosity, temperature, and<br/>radius were also compared. The initial-final mass relation plots showed that in the 1/10<br/>solar metallicity case, reducing the mass loss rate tended to increase the dependence of final mass on initial mass. The limited nature of these results implies a need for further study into the effects of using different mass loss rates in the code TYCHO.
ContributorsAuchterlonie, Lauren (Author) / Young, Patrick (Thesis director) / Shkolnik, Evgenya (Committee member) / Starrfield, Sumner (Committee member) / School of Earth and Space Exploration (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
131662-Thumbnail Image.png

Modeling Surface Brightness of the HH 901 Jets in the Carina Nebula

Description
The purpose of this thesis is to accurately simulate the surface brightness in various spectral emission lines of the HH 901 jets in the Mystic Mountain Formation of the Carina Nebula. To accomplish this goal, we gathered relevant spectral emission line data for [Fe II] 12660 Å, Hα 6563 Å,…

The purpose of this thesis is to accurately simulate the surface brightness in various spectral emission lines of the HH 901 jets in the Mystic Mountain Formation of the Carina Nebula. To accomplish this goal, we gathered relevant spectral emission line data for [Fe II] 12660 Å, Hα 6563 Å, and [S II] 6720 Å to compare with Hubble Space Telescope observations of the HH 901 jets presented in Reiter et al. (2016). We derived the emissivities for these lines from the spectral synthesis code Cloudy by Ferland et al. (2017). In addition, we used WENO simulations of density, temperature, and radiative cooling to model the jet. We found that the computed surface brightness values agreed with most of the observational surface brightness values. Thus, the 3D cylindrically symmetric simulations of surface brightness using the WENO code and Cloudy spectral emission models are accurate for jets like HH 901. After detailing these agreements, we discuss the next steps for the project, like adding an external ambient wind and performing the simulations in full 3D.
ContributorsMohan, Arun (Author) / Gardner, Carl (Thesis director) / Jones, Jeremiah (Committee member) / Computer Science and Engineering Program (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
165114-Thumbnail Image.png

3D Numerical Simulation of the Carina Astrophysical Jet HH901 with Cross Wind

Description

The purpose of this thesis is to accurately simulate in 3D the HH901 jet in the Mystic Mountain Formation of the Carina Nebula. Astronomers present a narrow-band Wide Field Camera image of Carina and the morphology of some astrophysical jets, including HH901. The simulation attempts to replicate features of the…

The purpose of this thesis is to accurately simulate in 3D the HH901 jet in the Mystic Mountain Formation of the Carina Nebula. Astronomers present a narrow-band Wide Field Camera image of Carina and the morphology of some astrophysical jets, including HH901. The simulation attempts to replicate features of the jet, among which are pulses, bow shock, terminal Mach disk, and Kelvin-Helmholtz rollup. We use the gas dynamical equations to solve for density, velocity, and temperature. The numerical methods used to solve the equations are third-order WENO (weighted essentially non-oscillatory) and third-order Runge-Kutta. Graphs of density and radiative cooling demonstrate the effect of adding wind (nonzero ambient velocity). The paper discusses the altering of the ambient velocity and final time to fit the shape of the jet in the Hubble image. The suggested next steps are simulating the other HH901 jet and comparing the jets’ atomic makeups to advance understanding of astrophysical jets.
ContributorsBuyer, Michael (Author) / Gardner, Carl (Thesis director) / Jones, Jeremiah (Committee member) / Barrett, The Honors College (Contributor) / Computer Science and Engineering Program (Contributor) / School of Mathematical and Statistical Sciences (Contributor)
Created2022-05