A5051042510- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Galaxies: Formation, Evolution, Phenomena
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Fatigue and fracture mechanics
- Astronomical Observations and Instrumentation
- Engineering Structural Analysis Methods
- Material Properties and Failure Mechanisms
- Adaptive optics and wavefront sensing
- Nuclear and radioactivity studies
- Engineering Diagnostics and Reliability
- Mechanical stress and fatigue analysis
- Ultrasonics and Acoustic Wave Propagation
- Space Science and Extraterrestrial Life
- Australian Indigenous Culture and History
- History and Developments in Astronomy
- Structural Integrity and Reliability Analysis
- Material Properties and Applications
- Risk and Safety Analysis
- Advanced Vision and Imaging
- Mechanical Behavior of Composites
- Phase Equilibria and Thermodynamics
- High-Velocity Impact and Material Behavior
University of California, Santa Cruz
2019-2023
Columbia University
2023
Space Telescope Science Institute
2019
Max Planck Institute for Astronomy
2019
Max Planck Society
2019
United Kingdom Atomic Energy Authority
1966-1989
We present image-based evolution of galaxy mergers from the Illustris cosmological simulation at 12 time-steps over 0.5 < z 5. To do so, we created approximately one million synthetic deep Hubble Space Telescope and James Webb images measured common morphological indicators. Using merger tree, assess methods to observationally select with stellar mass ratios as low 10:1 completing within +/- 250 Myr mock observation. confirm that one- or two-dimensional statistics so defined purity...
Abstract The Panchromatic Hubble Andromeda Southern Treasury (PHAST) is a large 195-orbit Space Telescope program imaging ∼0.45 deg 2 of the southern half M31's star-forming disk at optical and near-ultraviolet (NUV) wavelengths. PHAST survey area extends northern coverage (PHAT) down to M31, covering out radius ∼13 kpc along major axis in total ∼two-thirds disk. This new legacy yields stellar photometry over 90 million resolved stars using Advanced Camera for Surveys (F475W F814W), Wide...
We present initial results from a large spectroscopic survey of stars throughout M33's stellar disk. analyze sample 1667 red giant branch (RGB) extending to projected distances $\sim 11$ kpc center ($\sim 18$ kpc, or 10$ scale lengths, in the plane disk). The line-of-sight velocities RGB show presence two kinematical components. One component is consistent with rotation HI disk and has velocity dispersion 19$ km s$^{-1}$) that observed comparison younger stars, while second significantly...
Triangulum, M33, is a low mass, relatively undisturbed spiral galaxy that offers new regime in which to test models of dynamical heating. In spite its proximity, the heating history M33 has not yet been well constrained. this work, we present TREX Survey, largest stellar spectroscopic survey across disk M33. We kinematics as function age study past and ongoing measure line sight velocities for ~4,500 stars. Using subset, divide stars into broad bins using Hubble Space Telescope...
We analyze the kinematics of Andromeda's disk as a function stellar age by using photometry from Panchromatic Hubble Andromeda Treasury (PHAT) survey and spectroscopy Spectroscopic Photometric Landscape Stellar Halo (SPLASH) survey. use HI 21-cm CO ($\rm J=1 \rightarrow 0$) data to examine difference between deprojected rotation velocity gas that stars. divide stars into four bins, shortest lived longest lived: massive main sequence (0.03 Gyr), more luminous intermediate mass asymptotic...
Abstract We present a detailed analysis of the structure Local Group flocculent spiral galaxy M33, as measured using Panchromatic Hubble Andromeda Treasury Triangulum Extended Region (PHATTER) survey. Leveraging multiwavelength coverage PHATTER, we find that oldest populations are dominated by smooth exponential disk with two distinct arms and classical central bar—completely from what is seen in broadband optical imaging, first-ever confirmation bar M33. estimate extent ∼1 kpc. The...
We present late-time ($\sim$240-260 days after peak brightness) optical photometry and nebular (+236 +264 days) spectroscopy of SN 2018oh, the brightest Type Ia supernova (SN Ia) observed by Kepler telescope. The Kepler/K2 30-minute cadence observations started before explosion continued past brightness. For several explosion, 2018oh had blue "excess" flux in addition to a normal rise. excess can be explained interaction between Roche-lobe filling non-degenerate companion star. Such scenario...
Stellar kinematics and metallicity are key to exploring formation scenarios for galactic disks halos. In this work, we characterized the relationship between photometric along line-of-sight M31's disk. We combined optical HST/ACS photometry from Panchromatic Hubble Andromeda Treasury (PHAT) survey with Keck/DEIMOS spectra Spectroscopic Photometric Landscape of Andromeda's Halo (SPLASH) survey. The resulting sample 3512 individual red giant branch stars spans 4-19 projected kpc, making it a...
We explore the effect of active galactic nucleus (AGN) feedback from central galaxies on their satellites by comparing two sets cosmological zoom-in runs 27 halos with masses ranging $10^{12}$ to $10^{13.4}$ solar at z=0, (wAGN) and without (noAGN) AGN feedback. Both simulations include stellar multiple processes, including powerful winds supernovae, young massive stars, AGB radiative heating within Str\"omgren spheres photoelectric heating. Our wAGN model is identical noAGN except that it...
Abstract The presence of asymptotic giant branch (AGB) stars in clusters provides key constraints for stellar models, as has been demonstrated with historical data from the Magellanic Clouds. In this work, we look candidate AGB M31 star Panchromatic Hubble Andromeda Treasury survey. Our photometric criteria selects brighter than tip red branch, which includes bulk thermally pulsing well early-AGB and other luminous cool giants expected young populations (e.g., massive supergiants,...
We analyze the kinematics as a function of stellar age for Andromeda (M31) mass analogs from IllustrisTNG cosmological simulation. divide star particles into four groups: less than 1 Gyr, to 5 10 and greater compare these groups that neutral gas cells. calculate rotation curves gaseous components each analog 2 kpc 20 center mass. find lag, or asymmetric drift (AD), between curve on average increases with age. This finding is consistent observational measurements AD in disk galaxy. When M31...
Abstract The dwarf galaxy Triangulum (M33) presents an interesting testbed for studying stellar halo formation: it is sufficiently massive so as to have likely accreted smaller satellites, but also lies within the regime where feedback and other “in situ” formation mechanisms are expected play a role. In this work, we analyze line-of-sight kinematics of stars across M33 from TREX survey, with view understanding origin its halo. We split our sample into two broad populations varying age,...
Stellar kinematics and metallicity are key to exploring formation scenarios for galactic disks halos. In this work, we characterized the relationship between photometric along line-of-sight M31's disk. We combined optical HST/ACS photometry from Panchromatic Hubble Andromeda Treasury (PHAT) survey with Keck/DEIMOS spectra Spectroscopic Photometric Landscape of Andromeda's Halo (SPLASH) survey. The resulting sample 3512 individual red giant branch stars spans 4-19 projected kpc, making it a...
The dwarf galaxy Triangulum (M33) presents an interesting testbed for studying stellar halo formation: it is sufficiently massive so as to have likely accreted smaller satellites, but also lies within the regime where feedback and other "in-situ" formation mechanisms are expected play a role. In this work, we analyse line-of-sight kinematics of stars across M33 from TREX survey with view understanding origin its halo. We split our sample into two broad populations varying age, comprising...
The Great Andromeda Galaxy (M31) is the nexus of near-far galaxy evolution connection and a principal data point for near-field cosmology. Due to its proximity (780 kpc), M31 can be resolved into individual stars like Milky Way (MW). Unlike MW, we have advantage global view M31, enabling observed with techniques that also apply more distant galaxies. Moreover, recent evidence suggests may survived major merger within last several Gyr, shaping morphology stellar halo triggering starburst,...