The goal of this project is to introduce time dependence into SNEWPY’s flavor transformation prescriptions so as to better model expected neutrino signals.

The neutrino burst signal from a Galactic core-collapse supernova contains a wealth of information about the dynamics of the explosion, nuclear physics under extreme conditions, and the properties of the neutrino. In order to connect simulations of core-collapse supernovae with the expected signals in neutrino detectors, the SNEWS collaboration recently released a software package known as SNEWPY. SNEWPY is able to extract from simulation results the emitted neutrino spectra and then apply a flavor transformation prescription to account for the effects of flavor transformation as the neutrinos propagate to Earth. At the present time the flavor transformation prescriptions in SNEWPY are all static, however time dependence of the flavor transformation is expected due to the passage of the shockwave through the mantle of the star. This will be achieved by first attaching a parametric model of the stellar envelope to a progenitor data file. We will then extract from the simulation data the position and velocity of the shock which we can then extrapolate into the newly attached envelope. This will allow us to construct density profiles of the supernova containing the shock which can then be fed into a newly built SNEWPY extension which computes the flavor transformation probabilities through such profiles. These probabilities are then used to compute the flux of neutrinos at Earth which now possess the shock signatures. After development and verification, the code to undertake the shockwave calculations will be merged into the publicly available version of SNEWPY.

The goal of this project is to predict the observational signatures of dark matter annihilation radiation.

One of the leading theories for the nature of the mysterious dark matter that binds galaxies together is that it is a new fundamental particle that can annihilate to produce high-energy particles and radiation in areas of high density. This project will allow the student to trace the influence of dark matter annihilation over cosmic time from the epoch of the formation of the first stars, to show how the annihilation radiation might be detectable in studies of the “cosmic dawn” currently being carried out with state-of-the-art radio telescope facilities. This project will require the student to gain facility with an existing radiation-transfer code and to apply the results to simulations of future radio data, while learning the basics of galaxy formation and dark matter theory.

The goal of this project is to use data science methods to analyze a large set of core-collapse supernova simulations to provide novel constraints on the input variables.

Core-collapse supernovae remain a grand challenge of astrophysics. In particular, three- dimensional simulations remain computationally expensive endeavors. In addition, there are both numerical and physical uncertainties which are not yet fully under control. This leaves large-scale parameter studies in 3D an impossible goal at the present time. In recent years, complementary methods to sophisticated, full 3D simulations have been developed [5]. These "effective" methods parametrize a critical ingredient to the explosion in a physically- motivated way, often self-consistent within the framework (eg redirecting energy from mu/tau neutrinos to neutrino heating instead of adding extra energy to the system by hand). These effective setups are ideal for large parameter studies, connecting input variables (eg stellar mass, initial metallicity, nuclear equation of state, etc) with output variables (explosion energy, remnant mass, nucleosynthetic yields, etc). The student will learn data science techniques and will correctly apply them to existing data sets of core-collapse supernova simulations. The student will extract comparable data from observations and make meaningful comparisons between the synthetic and the observed supernova populations.

The goal of this project is to compare numerical biconical outflow models with observations to infer the outflow deceleration profile and mass outflow rates from the Galactic Center.

The Galactic Center at the heart of the Milky Way is driving a nuclear wind that can be seen as a giant structure of plasma extending for 10kpc on either side of the Galactic Center [1]. These structures are called the Fermi Bubbles and they trace an explosive event from the heart of the Milky Way a few Myrs ago. Outflowing gas is visible in enhanced emission in many parts of the electromagnetic spectrum, including Fermi gamma-ray bubbles and radio lobes extending above and below the Galactic Center. We are currently pursuing a campaign to map the kinematics and extent of this nuclear outflow, using UV spectroscopy from Hubble Space Telescope [2, 3, 4]. New data is being collected, and an undergraduate student will analyze the UV spectra of background AGN and halo-stars lying close on the sky to the Galactic Center. Any variation in absorption properties with Galactic latitude will allow us to constrain the physical conditions in the outflowing gas. The participant will learn to analyze UV spectroscopy from Hubble and will learn to use Python programs to quantify the measurements. The undergraduate students will learn to code and use simple numerical biconical outflow models to interpret these observations in terms of the geometry of the gas flow.

The goal of this project will be to determine the extent to which theoretically calculated beta decay rates introduce an uncertainty in the r-process cosmochronometers.

One of the foremost goals of nuclear astrophysics is to understand the origins of the heaviest elements. The only known nucleosynthesis process that can create heavy elements up to uranium and thorium is rapid neutron capture, or r-process, nucleosynthesis. Exactly where an d how the r-process occurs has not been definitively determined in a way that explains all of the observational data. Progress on determining the astrophysical site of the r-process has been hindered by a lack of understanding of the physics of nuclei far from stability that lie along the r-rpocess path. We will study the features of the r-process pattern and the underlying physics which causes them to form in a variety of potential r-process sites. Our focus will be on the role of beta decay in the r-process. The undergraduate will learn to use a reaction network code and to process the data it produces. Several different theoretical compilations of beta decay rates will be used to calculate r-process nucleosynthesis in three different types of astrophysical environments. The ratios of relevant actinide and lanthanide elements will be determined together with their uncertainties and a comparison will be made with data from metal poor stars. If time permits we will identify the beta decay rates that introduce the largest uncertainties, and have discussions with experimentalists who could potentially measure these rates at radioactive beam facilities, such as the Facility for Rare Isotope Beams.

The goal of this project is to characterize the temporal behavior of gravitational accretion onto a neutron star in a clumpy stellar wind.

The large time variability of the x-ray flux in Supergiant Fast X-ray Transients is typically attributed to the inferred presence of dense clumps in the wind of the hot primary star. In this theory the added mass of clumps passing within the classical Bondi-Hoyle-Lyttleton accretion radius of the companion neutron star enhances the mass accretion rate and hence the X-ray flux [6]. This simple model neglects the fact that the dynamics of accretion onto a compact star is dominated by angular momentum. If the wind clump is not approaching the neutron star head on it will represent sufficient angular momentum to form an accretion torus and prevent accretion onto the neutron star. This conceptually simple hydrodynamics problem is ideal for an undergraduate project. The participant can start by modifying a basic code to model Bondi accretion in one dimension and quickly ramp up to three dimensions using existing hydrodynamics codes. The participant will be able to run several 3D models and quantify the effects of net mass and angular momentum in the upstream flow on the mass accretion rate.