Melissa Halford
A5010036227- Gamma-ray bursts and supernovae
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- Cardiac Arrest and Resuscitation
- Laser Design and Applications
- Advanced Chemical Physics Studies
- Pulsars and Gravitational Waves Research
- Astrophysics and Cosmic Phenomena
- Atomic and Molecular Physics
- Particle physics theoretical and experimental studies
- Geophysics and Sensor Technology
- SAS software applications and methods
- Mass Spectrometry Techniques and Applications
- Solar and Space Plasma Dynamics
- Atomic and Subatomic Physics Research
Auburn University
2020-2023
University of Arizona
2014-2015
Abstract We present UV and/or optical observations and models of SN 2023ixf, a type II supernova (SN) located in Messier 101 at 6.9 Mpc. Early time ( flash ) spectroscopy obtained primarily Lick Observatory, reveals emission lines H i , He i/ii C iv N iii/iv/v with narrow core broad, symmetric wings arising from the photoionization dense, close-in circumstellar material (CSM) around progenitor star prior to shock breakout. These electron-scattering broadened line profiles persist for ∼8 days...
We present time series photometric and spectroscopic data for the transient SN 2009ip from start of its outburst in September 2012 until November 2013. This was collected primarily with new robotic capabilities Las Cumbres Observatory Global Telescope Network, a specialized facility domain astrophysics, includes supporting high-resolution spectroscopy Southern Astrophysical Research Telescope, Kitt Peak National Observatory, Gemini Observatory. Based on our nightly monitoring, we interpret...
We present optical, ultraviolet, and infrared data of the type II supernova (SN II) 2020jfo at 14.5 Mpc. This wealth multiwavelength allows to compare different metrics commonly used estimate progenitor masses SN for same object. Using its early light curve, we infer had a radius $\approx$700 $R_{\odot}$, consistent with red supergiants initial mass $M_{\rm ZAMS}=$11-13 $M_{\odot}$. The decline in late-time curve is best fit by ${}^{56}$Ni 0.018$\pm$0.007 $M_{\odot}$ that ejected from II-P...
We present UV/optical observations and models of supernova (SN) 2023ixf, a type II SN located in Messier 101 at 6.9 Mpc. Early-time ("flash") spectroscopy obtained primarily Lick Observatory, reveals emission lines H I, He I/II, C IV, N III/IV/V with narrow core broad, symmetric wings arising from the photo-ionization dense, close-in circumstellar material (CSM) around progenitor star prior to shock breakout. These electron-scattering broadened line profiles persist for $\sim$8 days respect...
Dynamical mass calculations have suggested that the Milky Way globular cluster NGC 6535 belongs to a population of clusters with high mass-to-light ratios, possibly due bottom-heavy stellar initial function. We use published Hubble Space Telescope data measure present day function this within its half-light radius and instead find it is bottom-light, exacerbating discrepancy between dynamical measurement known content. The cluster's proximity bulge relatively strong velocity anisotropy are...