A5100345070- Stellar, planetary, and galactic studies
- Astrophysical Phenomena and Observations
- Astronomy and Astrophysical Research
- Pulsars and Gravitational Waves Research
- Astrophysics and Star Formation Studies
- Gamma-ray bursts and supernovae
- Galaxies: Formation, Evolution, Phenomena
- Adaptive optics and wavefront sensing
- Relativity and Gravitational Theory
- Astronomical Observations and Instrumentation
- Astronomical and nuclear sciences
- History and Developments in Astronomy
- Experimental and Theoretical Physics Studies
- Heat Transfer Mechanisms
- CCD and CMOS Imaging Sensors
- Solar and Space Plasma Dynamics
University of Washington
2023-2024
University of California, Los Angeles
2019-2023
Gravitational redshift in the Galactic Center General relativity predicts that light emitted by an object a strong gravitational field—for example, close to black hole—should be shifted longer wavelengths. This does not exist Newtonian theory of gravity. Do et al. monitored position and spectrum star S0-2 as it passed Sagittarius A*, supermassive hole at center Milky Way. Around closest part S0-2's 16-year orbit, they detected effect on its spectrum. These results are more consistent with...
The electromagnetic counterpart to the Galactic center supermassive black hole, Sgr A*, has been observed in near-infrared for over 20 years and is known be highly variable. We report new Keck Telescope observations showing that A* reached much brighter flux levels 2019 than ever measured at wavelengths. In K$^\prime$ band, of $\sim6$ mJy, twice level previously peak from $>13,000$ measurements 130 nights with VLT Telescopes. also observe a factor 75 change 2-hour time span no obvious color...
We report the first star formation history study of Milky Way's nuclear cluster (NSC) that includes observational constraints from a large sample stellar metallicity measurements. These measurements were obtained recent surveys Gemini and VLT 770 late-type stars within central 1.5 pc. measurements, along with photometry spectroscopically derived temperatures, are forward modeled Bayesian inference approach. Including improves overall fit quality, as low-temperature red giants previously...
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...
Abstract We present the results of first systematic search for spectroscopic binaries within central 2 × 3 arcsec around supermassive black hole at center Milky Way galaxy. This survey is based primarily on over a decade adaptive optics-fed integral-field spectroscopy ( R ∼ 4000), obtained as part Galactic Center Orbits Initiative Keck Observatory, and it has limiting K ’-band magnitude 15.8, which least 4 mag deeper than previous searches larger radii nuclear star cluster. From this primary...
Abstract We report new infrared (IR) measurements of the supermassive black hole at Galactic Center, Sgr A*, over a decade that was previously inaccessible these wavelengths. This enables variability study addresses timescales are 10 times longer than earlier published studies. A* initially detected in near-infrared (NIR) with adaptive optics observations 2002. While data exists form speckle imaging (1995–2005), not initial analysis. Here, we improved our holography analysis techniques. has...
Elemental abundances are key to our understanding of star formation and evolution in the Galactic center. Previous work on this topic has been based infrared (IR) observations, but X-ray observations have potential constraining abundance heavy elements, mainly through their K-shell emission lines. Using 5.7 Ms Chandra we provide first measurement Si, S, Ar, Ca Fe, four prominent diffuse features located central parsec Galaxy, which manifestation shock-heated hot gas. A two-temperature,...
As the closest example of a galactic nucleus, Galactic center (GC) presents an exquisite laboratory for learning about supermassive black holes (SMBH) and their environment. We describe several exciting new research directions that, over next 10 years, hold potential to answer some biggest scientific questions raised in recent decades: Is General Relativity (GR) correct description holes? What is nature star formation extreme environments? How do stars compact objects dynamically interact...
Abstract deepCR is a deep-learning-based cosmic-ray (CR) rejection framework originally presented by Zhang & Bloom. The original approach requires dedicated training set that consists of multiple frames the same fields, enabling automatic CR labeling through comparison with their median coadds. Here, we present novel circumvents need for set, but instead utilizes dark and science images requiring removal themselves. During training, CRs in are added to images, which network then trained...
Abstract We measure the high-mass stellar initial mass function (IMF) from resolved stars in M33 young clusters. Leveraging Hubble Space Telescope’s high resolving power, we fully model IMF probabilistically. first optical color–magnitude diagram of each cluster to constrain its power-law slope Γ, marginalized over other parameters fit (e.g., age, mass, and radius). then probabilistically distribution (MF) slopes for a highly strict sample nine clusters more massive than log(Mass/ M ⊙ ) =...
While the Milky Way Nuclear star cluster has been studied extensively, how it formed is uncertain. Studies have shown contains a solar and supersolar metallicity population that may in-situ, along with subsolar via mergers of globular clusters dwarf galaxies. Stellar abundance measurements are critical to differentiate between formation scenarios. We present new [$M/H$] $\alpha$-element abundances [$\alpha/Fe$] two subsolar-metallicity stars in Galactic Center. These observations were taken...
We measure the high-mass stellar initial mass function (IMF) from resolved stars in M33 young clusters. Leveraging \textit{Hubble Space Telescope's} high resolving power, we fully model IMF probabilistically. first optical CMD of each cluster to constrain its power-law slope $\Gamma$, marginalized over other parameters fit (e.g., age, mass, and radius). then probabilistically distribution MF slopes for a highly strict sample 9 clusters more massive than log(Mass/M$_{\odot}$)=3.6; above this...
We present the results of first systematic search for spectroscopic binaries within central 2 x 3 arcsec$^2$ around supermassive black hole at center Milky Way galaxy. This survey is based primarily on over a decade adaptive optics-fed integral-field spectroscopy (R$\sim$4000), obtained as part Galactic Center Orbits Initiative Keck Observatory, and has limiting $K$'-band magnitude 15.8, which least 4 magnitudes deeper than previous searches larger radii nuclear star cluster. From this...
Elemental abundances are key to our understanding of star formation and evolution in the Galactic center. Previous work on this topic has been based infrared (IR) observations, but X-ray observations have potential constraining abundance heavy elements, mainly through their K-shell emission lines. Using 5.7 Ms Chandra we provide first measurement Si, S, Ar, Ca Fe, four prominent diffuse features located central parsec Galaxy, which manifestation shock-heated hot gas. A two-temperature,...
We report the first star formation history study of Milky Way's nuclear cluster (NSC) that includes observational constraints from a large sample stellar metallicity measurements. These measurements were obtained recent surveys Gemini and VLT 770 late-type stars within central 1.5 pc. measurements, along with photometry spectroscopically derived temperatures, are forward modeled Bayesian inference approach. Including improves overall fit quality, as low-temperature red giants previously...