Short gamma-ray bursts (GRBs) are explosions of cosmic origins believed to be associated with the merger of two compact objects, either two neutron stars or a neutron star and a black hole (BH). The presence of at least one neutron star has long been thought to be an essential element...
From the earliest English colonization to the present day, there
has been interest in astronomy in this country. The purpose of this
thesis is to show how the science of astronomy developed in America
from the earliest observations by educated colonists using imported
instruments and publishing in European journals, to...
Computational simulations of disks are becoming an important tool to predict the the evolution of protostars and disks to better understand the formation of planets. Past research has shown that the evolution of disks and their protostar can be altered through the interaction between gravity and hydrodynamic instabilities. We perform...
Core-collapse supernovae (CCSNe) are considered to be important contributors to the primitive dust enrichment of the interstellar medium in the high-redshift universe. Theoretical models of dust formation in stellar explosions have so far provided controversial results and a generally poor fit to the observations of dust formation in local supernovae....
One of the most important unresolved issues in gamma-ray burst (GRB) physics is the origin of the prompt gamma-ray spectrum. Its general non-thermal character and the softness in the X-ray band remain unexplained. We tackle these issues by performing Monte Carlo simulations of radiation-matter interactions in a scattering dominated photon-lepton...
Studying the evolution of the Milky Way galaxy helps us understand our place in the Universe. Early evolution of the Galaxy can effectively be studied by observing stars with low metallicity values since they are the oldest stars still visible. Due to the formation of the Galaxy, the oldest stars...
We present an analysis of the relationship between spectral lag and luminosity in time-resolved segments of long gamma-ray bursts detected by BATSE, an experiment aboard the Compton Gamma Ray Observatory satellite. For full bursts, there is a well-established correlation between the lag, which is easily computed, and the total burst...
We study the late-time (t > 0.5 days) X-ray afterglows of nearby (z < 0.5) long gamma-ray bursts (GRBs) with Swift and identify a population of explosions with slowly decaying, super-soft (photon index Γx > 3) X-ray
emission that is inconsistent with forward shock synchrotron radiation associated with the afterglow....