During the first 100 million years after the Big Bang the universe was dark, and possibly full of terrors. Sometime during the first 500 million years, these cosmic dark ages ended with the ignition of the first stars. The first stars, which we call these Population III, contained only the hydrogen and helium formed in the Big Bang. These stars are interesting because they are thought to have started a domino effect of enrichment of elements heavier than helium through the cosmos. These ”heavier” elements formed in the core of stars are referred to in astronomy as ”metals”. Without ”metals” the gas out of which Population III stars form cools inefficiently, producing stars with masses as high as a few 1000 times the mass of our Sun. However, while we know that Population III stars are massive, we do not know exactly how massive as they are too faint for detection by all current and upcoming astronomy observatories. The work presented on this poster will explore one possible alternate avenue to answer the question: how massive were the first stars? As a result of their extreme masses, the most massive Population III stars will collapse directly into black holes with masses of a few hundred to a few thousand times the mass of our sun. A billion years after the Big Bang, as the era of the Population III stars ends, astronomers have observed the distribution of supermassive black holes (a million to a billion times the mass of the sun) in galaxies. Our work traces the evolution of the direct collapse black holes, formed from Population III stars, to determine whether the distribution of the masses of Population III stars left an imprint on the distribution of supermassive black holes, 500 million years later. The goal of this work is to randomly populate different potential distributions of Population III masses to compare the varying distributions of direct collapse black holes at different times. The result of this will eventually provide predictions for the dependence of the distribution of supermassive black holes, a billion years after the Big Bang, on the distribution of the masses of Population III stars.

Dark Matter (DM) is hypothesized to be an exotic particle that is invisible to human observation. But thankfully, its existence is proven through its gravitational interaction with luminous matter (such as stars and galaxies), and it is responsible for the formation of the humongous structures across our universe. The leading interpretation of DM is what we call Cold Dark Matter (CDM), where the DM particles have relatively low velocities and low energies. This causes structures to form quite quickly and easily in the early universe. While CDM can explain many observed properties of the universe, it is not without its flaws (specifically on the scale of low-mass dwarf galaxies). The hypothesis of Warm Dark Matter (WDM) poses a viable solution to the shortcomings of CDM. In WDM, the DM particles are of higher energy and have higher velocities. This would cause the formation of the first gravitationally bound structures in the Universe to be delayed when compared to CDM. Using a model to approximate varying temperatures of DM, we compare the rates and characteristics of early structure formation for the current CDM hypothesis, and that of many other types/temperatures of WDM. We expect that the differences between CDM and WDM will be most apparent during the first billion years after the Big Bang, just as the first stars in the Universe ignite. These results may be indicative of the true nature of dark matter, and finally bring our understanding into the light.

In this research we developed biocompatible Graphene Quantum Dots (GQDs) capable of emitting light in the infrared part of the light spectrum. Using the bottom up and top down approaches, we synthesized near-infrared light-emitting GQDs to be used for further cell studies as imaging and drug delivery agents for cancer detection and treatment.
From our bottom up approach, using a one-step hydrothermal reaction using a microwave and oven, the GQDs derived from the Glucose and Liquid ammonia mixture and those from from the L-glutamic acid showed near-infrared emission. And from our top down approach, using a UV based photolytic reaction, the GQDs derived from the mixture of urea, citric acid and hydrogen peroxide also showed near-infrared emission.

Type Ia Supernovae (SNe Ia) are used as measuring sticks in the structure of the Universe. These catastrophic explosions occur when two stars collide, but it’s unknown what kind of stars are combined to produce a SN Ia. Target 1 in our study is an unusual SN Ia; while a standard SN Ia would grow much dimmer after 300 days (late-time), this one remains bright. This is due to delayed interaction between the material ejected from the SN explosion colliding with the material in the surrounding region, causing light-curves to stagnate in late-time and be brighter than standard SNe Ia. It’s unknown if SNe like Target 1 are rare, but their properties would greatly aid in mapping the Universe. Therefore, we searched the public data from the Zwicky Transient Facility for more these types of SNe. We obtained 40 light-curves that are representative of the intrinsic SN Ia distribution in the nearby universe and found two instances of Target 1-like SNe.

Photothermal Therapy (PTT) provides a promising new method of therapy for various medical conditions, including cancer, using infrared wavelengths. In my project, the photothermal effect of various nanomaterials—including Reduced Graphene Oxide, gold nanospheres and nanorods, and Copper Sulfide (CuS) nanoparticles—is characterized by irradiation of the aqueous materials with near-infrared radiation. These materials were then irradiated in live cell cultures to characterize their potential use as a treatment candidate.