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Articles 1 - 10 of 10
Full-Text Articles in Astrophysics and Astronomy
Dirac Dark Matter, Neutrino Masses, And Dark Baryogenesis, Diego Restrepo, Andrès Rivera, Walter Tangarife
Dirac Dark Matter, Neutrino Masses, And Dark Baryogenesis, Diego Restrepo, Andrès Rivera, Walter Tangarife
Physics: Faculty Publications and Other Works
We present a gauged baryon number model as an example of models where all new fermions required to cancel out the anomalies help to solve phenomenological problems of the standard model (SM). Dark fermion doublets, along with the isosinglet charged fermions, in conjunction with a set of SM-singlet fermions, participate in the generation of small neutrino masses through the Dirac-dark Zee mechanism. The other SM-singlets explain the dark matter in the Universe, while their coupling to an inert singlet scalar is the source of the CP violation. In the presence of a strong first-order electroweak phase transition, this “dark” CP …
Reverberation Mapping Of Markarian 421 Using V,R, I, And Ha Filters, Alex Whitman
Reverberation Mapping Of Markarian 421 Using V,R, I, And Ha Filters, Alex Whitman
Honors Program Theses and Projects
Active Galactic Nuclei (AGN) at their most basic level are supermassive blackholes that emit light. While that sounds paradoxical, it speaks volumes to how little we know about these extraordinary objects. One technique that can be used, and was used here to better understand these objects is reverberation mapping. We employed this method on the AGN Markarian 421 (Mrk 421) at Bridgewater State University (BSU). Mrk 421 was chosen because it is the brightest known AGN, averaging 12.7 magnitudes, and the observational abilities of BSU are best suited for objects brighter than 18 magnitudes in optical wavelengths. We observed Mrk …
Monitoring The M-Dwarf Host Stars Of Tess Exoplanet Candidates: Stellar Flares And Habitability, Ashley Lieber
Monitoring The M-Dwarf Host Stars Of Tess Exoplanet Candidates: Stellar Flares And Habitability, Ashley Lieber
Physics Undergraduate Honors Theses
In the search for life beyond our solar system, the study of M-dwarfs has become increasingly important due to their unique characteristics including their small size, flaring capabilities, and long lifespans. Their small size allows for exoplanet detection due to observable gravitational interactions, and the stellar flares could potentially trigger prebiotic life on exoplanets in the system. Lastly, their long lifespans may provide the conditions necessary to foster prebiotic life and the development of more complex organisms over time. Flare rate is a critical factor in determining the habitability of the exoplanet due to its potential to damage or incubate …
Electromagnetic Detectability Of Binary Supermassive Black Holes, Kaylee Grace
Electromagnetic Detectability Of Binary Supermassive Black Holes, Kaylee Grace
Honors Scholar Theses
Supermassive black hole (SMBH) binaries can be produced by galaxy mergers and are important sources of gravitational waves. Although several binary candidates have been identified in previous work, none have yet been fully confirmed. These pairs are difficult to detect, since single accreting SMBHs can have pseudo-periodic lightcurves due to stochastic noise that can mimic the signature of binary SMBHs. The aforementioned lightcurves are the detections we classify as ”false-positive.” The Vera Rubin Observatory (VRO) will be a powerful new tool for detecting binary SMBHs. We determine the false-positive binary detection rate for VRO by attempting to recover sinusoidal binary …
Signal Yields And Detector Modeling In Xenon Time Projection Chambers, And Results Of An Effective Field Theory Dark Matter Search Using Lux Data, Gregory Ransford Carl Rischbieter
Signal Yields And Detector Modeling In Xenon Time Projection Chambers, And Results Of An Effective Field Theory Dark Matter Search Using Lux Data, Gregory Ransford Carl Rischbieter
Legacy Theses & Dissertations (2009 - 2024)
The nature of dark matter continues to be one of the biggest remaining mysteries in physics. Astrophysical measurements indicate that dark matter makes up more than a quarter of the Universe's total energy density, and it is well-motivated that dark matter is comprised of Weakly Interacting Massive Particles (WIMPs). Direct detection techniques utilizing liquid and gaseous noble elements have become the primary method of probing the potential non-gravitational interactions between WIMPs and Standard Model matter, with the leading technology being the dual-phase Time Projection Chamber (TPC). The Large Underground Xenon (LUX) and its second-generation successor, LUX-ZEPLIN (LZ), are two xenon …
Physical Properties Of Brackett Emitters In The Apogee Dr17 Catalog, Elliott Khilfeh, Hunter Campbell, Kevin R. Covey, Marina Kounkel, Richard Ballentyne
Physical Properties Of Brackett Emitters In The Apogee Dr17 Catalog, Elliott Khilfeh, Hunter Campbell, Kevin R. Covey, Marina Kounkel, Richard Ballentyne
WWU Honors College Senior Projects
In the process of accumulating mass (accretion), young stars channel ionized gas from the protoplanetary disk to the stellar surface along magnetic field lines. Upon impacting the photosphere, the gas cools down, recombining and emitting hydrogen spectral lines. Measuring these emission lines allows us to determine the temperature and density of the gas in those accretion streams. This then enables us to test whether those parameters depend on the accretion rate. We present measurements of equivalent widths and line ratios for Brackett (Br) 11 – 20 lines for 3366 observations of 940 pre-main sequence stars observed with APOGEE as of …
Dayside Auroral Activity, Aine Merritt, Gerard J. Fasel
Dayside Auroral Activity, Aine Merritt, Gerard J. Fasel
Seaver College Research And Scholarly Achievement Symposium
The dayside aurora is greatly influenced by the solar wind. Many different types of dayside auroral features have been identified, including poleward-moving auroral forms (PMAFs), throat aurora, shock aurora, and diffuse aurora. This study looks at the dayside auroral activity using the BACC ground-based all-sky-cameras located in both Longyearbyen (Kjell Henriksen Observatory) and Ny-Alesund, Svalbard. There are times when PMAFs peel off the dayside auroral oval in an ordered fashion, elongated east-west arcs moving poleward. At other times, the dayside aurora displays arcs that have extreme brightening moving through the arcs as they exhibit swirls and become a bit chaotic …
Characterizing Agn Influence On The Calculated Metallicities Of Adjacent Star-Forming Spaxels, Aidan Khelil
Characterizing Agn Influence On The Calculated Metallicities Of Adjacent Star-Forming Spaxels, Aidan Khelil
Honors Papers
In this thesis, I introduce a method to identify and characterize the effects of active galactic nuclei (AGN) on the spectra of nearby star-forming regions. I analyze spatially-resolved areas of galaxies called “spaxels” within Data Release 15 of the Sloan Digital Sky Survey (SDSS) with the goal of locating those which are physically close to AGN. I find those spaxels with calculated metallicities which lie adjacent to AGN-flagged spaxels and characterize their metallicity values relative to the spaxels which are not adjacent to AGN-flagged spaxels, using a total of 11 separate metallicity calibrations. I find that the current methods to …
Accretion Onto A Black Hole At The Center Of A Neutron Star: Nuclear Equations Of State, Sophia Christina Schnauck
Accretion Onto A Black Hole At The Center Of A Neutron Star: Nuclear Equations Of State, Sophia Christina Schnauck
Honors Projects
A recent re-examination of Bondi accretion (see Richards, Baumgarte and Shapiro (2021)) revealed that, for stiff equations of state (EOSs), steady-state accretion can only occur for accretion rates exceeding a certain minimum. To date, this result has been explored only for gamma-law equations of state. Instead, we consider accretion onto a small black hole residing at the center of a neutron star governed by a more realistic nuclear EOS. We generalize the relativistic Bondi solution for such EOSs, approximated by piecewise polytropes, and thereby obtain analytical expressions for the accretion rates which were reflected in our numerical simulations. After taking …
Toward Deep Learning Emulators For Modeling The Large-Scale Structure Of The Universe, Neerav Kaushal
Toward Deep Learning Emulators For Modeling The Large-Scale Structure Of The Universe, Neerav Kaushal
Dissertations, Master's Theses and Master's Reports
Multi-billion dollar cosmological surveys are being conducted almost every decade in today’s era of precision cosmology. These surveys scan vast swaths of sky and generate tons of observational data. In order to extract meaningful information from this data and test these observations against theory, rigorous theoretical predictions are needed. In the absence of an analytic method, cosmological simulations become the most widely used tool to provide these predictions in order to test against the observations. They can be used to study covariance matrices, generate mock galaxy catalogs and provide ready-to-use snapshots for detailed redshift analyses. But cosmological simulations of matter …