A5031212885- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Galaxies: Formation, Evolution, Phenomena
- Astro and Planetary Science
- Astrophysical Phenomena and Observations
- Planetary Science and Exploration
- Astrophysics and Star Formation Studies
- High-pressure geophysics and materials
- Nuclear Physics and Applications
- Gamma-ray bursts and supernovae
- Space Satellite Systems and Control
- High-Velocity Impact and Material Behavior
- Nuclear Issues and Defense
- Space Science and Extraterrestrial Life
- Spacecraft and Cryogenic Technologies
- Nuclear and radioactivity studies
- Astronomical Observations and Instrumentation
- Geophysics and Gravity Measurements
- Scientific Research and Discoveries
- Adaptive optics and wavefront sensing
- Granular flow and fluidized beds
- Fluid Dynamics Simulations and Interactions
- Gas Dynamics and Kinetic Theory
- History and Developments in Astronomy
- Security and Verification in Computing
Lawrence Livermore National Laboratory
2012-2023
University of California, Santa Cruz
2007-2012
The combination of large size, high stellar density, metallicity, and Sérsic surface brightness profile the spheroidal component Andromeda galaxy (M31) within Rproj ∼ 20 kpc suggests that it is unlike any subcomponent Milky Way. In this work we capitalize on our proximity to external view M31 probe kinematical properties "inner spheroid." We employ a Markov chain Monte Carlo (MCMC) analysis resolved kinematics from Keck/DEIMOS spectra 5651 red giant branch stars disentangle M31's inner...
As part of the Panchromatic Hubble Andromeda Treasury (PHAT) multi-cycle program, we observed a 12' \times 6.5' area bulge M31 with WFC3/UVIS filters F275W and F336W. From these data have assembled sample \sim4000 UV-bright, old stars, vastly larger than previously available. We use updated Padova stellar evolutionary tracks to classify hot stars into three classes: Post-AGB (P-AGB), Post-Early AGB (PE-AGB) AGB-manqu\'e stars. P-AGB are end result asymptotic giant branch (AGB) phase expected...
As part of the SPLASH survey Andromeda (M31) system, we have obtained Keck/DEIMOS spectra compact elliptical (cE) satellite M32. This is first resolved-star kinematical study any cE galaxy. In contrast to most previous studies that extended out r ≲ 30'' ∼ 1 reffI 100 pc, measure rotation curve and velocity dispersion profile 250'' higher order Gauss–Hermite moments 70''. We achieve this by combining integrated-light spectroscopy at small radii (where crowding/blending are severe) with...
NGC 205, a close satellite of the M31 galaxy, is our nearest example dwarf elliptical galaxy. Photometric and kinematic observations suggest 205 undergoing tidal distortion from its interaction with M31. Despite earlier attempts, orbit progenitor properties are not well known. We perform an optimized search for these unknowns by combining genetic algorithm restricted N-body simulations interaction. Coupled photometric as constraints, this allows effective exploration parameter space....
The threat of asteroid impacts on Earth poses a low-probability but high consequence risk, with possible outcomes ranging from regional to global catastrophe. However, unique amongst such threats we have the capability averting disasters. Diversion approaches by either kinetic impactor or nuclear energy deposition are two most practical technologies for mitigating hazardous near asteroids. One greatest challenges in understanding our options is uncertain response asteroids impulsive...
ABSTRACT We spectroscopically identify a sample of carbon stars in the satellites and halo M31 using moderate-resolution optical spectroscopy from Spectroscopic Photometric Landscape Andromeda’s Stellar Halo survey. present photometric properties our 41 stars, including their brightness with respect to tip red giant branch (TRGB) distributions various color–color spaces. This analysis reveals bluer population fainter than TRGB redder brighter TRGB. then apply principal component determine...
Abstract In the event of a potentially catastrophic asteroid impact, with sufficient warning time, deploying nuclear device remains powerful option for planetary defense if kinetic impactor or other means deflection proves insufficient. Predicting effectiveness potential disruption mission depends on accurate multiphysics simulations device's X-ray energy deposition into and resulting material ablation. The relevant physics in these span many orders magnitude, require variety different...
As part of the SPLASH survey Andromeda galaxy (M31) and its neighbors, we have obtained Keck/DEIMOS spectra compact elliptical (cE) satellite M32. This is first resolved-star kinematical study any cE galaxy. In contrast to previous studies that extended out r<30"~1Re~100pc, measure rotation curve velocity dispersion profile r~250" higher order Gauss-Hermite moments r~70". We achieve this by combining integrated-light spectroscopy at small radii (where crowding/blending are severe) with...