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Constraining H0 Via Extragalactic Parallax, Nicholas Ferree
Constraining H0 Via Extragalactic Parallax, Nicholas Ferree
Honors Theses
We examine the prospects for measurement of the Hubble parameter 𝐻0 via observation of the secular parallax of other galaxies due to our own motion relative to the cosmic microwave background rest frame. Peculiar velocities make distance measurements to individual galaxies highly uncertain, but a survey sampling many galaxies can still yield a precise 𝐻0 measurement. We use both a Fisher information formalism and simulations to forecast errors in 𝐻0 from such surveys, marginalizing over the unknown peculiar velocities. The optimum survey observes ∼ 102 galaxies within a redshift 𝐻0max = 0.06. The required errors …
The Rotational Period Distribution Of Massive Magnetic White Dwarfs, Zorayda Martinez
The Rotational Period Distribution Of Massive Magnetic White Dwarfs, Zorayda Martinez
Honors Theses
Rapidly rotating white dwarfs (WDs) have the potential to come about by either double degenerate mergers or weak coupling between the core and the outer envelope during the asymptotic giant branch (AGB). For both cases, knowledge of the rotational period distribution places tight constraints on the evolution of angular momentum transfer. Here we present initial results from a study of the rotational period distribution of 19 massive (M > 0:9M), magnetic, DA WDs observed by the Transiting Exoplanet Survey Satellite (TESS) and 17 observed with ground-based telescopes and analyzed with the Lightkurve python package. We present periodograms, folded light curves, and …
Optimal Method For Reconstructing Polychromatic Maps From Broadband Observations With An Aysmmetric Antenna Pattern, Brianna Cantrall, Emory F. Bunn, Solomon Quinn
Optimal Method For Reconstructing Polychromatic Maps From Broadband Observations With An Aysmmetric Antenna Pattern, Brianna Cantrall, Emory F. Bunn, Solomon Quinn
Honors Theses
Broadband time-ordered data obtained from telescopes with a wavelength-dependent, asymmetric beam pattern can be used to extract maps at multiple wavelengths from a single scan. This technique is especially useful when collecting data on cosmic phenomena such as the Cosmic Microwave Background (CMB) radiation, as it provides the ability to separate the CMB signal from foreground contaminants. We develop a method to determine the optimal linear combinations of wavelengths (“colors”) that can be reconstructed for a given telescope design and the number of colors that are measurable with high signal-to-noise ratio. The optimal colors are found as eigenvectors of a …
Membership Probabilities Of White Dwarfs In Open Star Clusters, Sarah Phillips
Membership Probabilities Of White Dwarfs In Open Star Clusters, Sarah Phillips
Honors Theses
This thesis explores the relationship between astronomical position data and star cluster membership. Our research project focuses on the mathematical probability of cluster membership for white dwarf stars (WDs), specifically membership candidates within the open cluster Messier 35. Through Gaussian analysis of proper motion data, we examine the membership probability of each candidate. Establishing cluster membership has broad applications and can allow further determination of a star’s characteristics including stellar age and evolution. Of particular interest are two WD member candidates for Messier 35: LAWDS 4, a DB WD with a helium-dominated atmosphere as opposed to the more common hydrogen-dominated …
Evaluating Neutron Star Binding Energies Using Rotating Accreting Models, Nathan Moore
Evaluating Neutron Star Binding Energies Using Rotating Accreting Models, Nathan Moore
Honors Theses
Neutron star binding energy increases due to accreting matter from neighboring astronomical bodies, and decreases due to the star spinning up, increasing its angular velocity. We present a novel set of models that account for both increasing angular velocity and accreting matter to track a neutron star’s evolution. We arrive at these models through studying and reconfiguring computational investigations from the past, particularly a code which generates a model for a given fixed baryon mass and angular velocity and another that takes it from one baryon mass and angular velocity to the next one through accretion, to obtain a full …