A5035585472- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Calibration and Measurement Techniques
- Adaptive optics and wavefront sensing
- Ionosphere and magnetosphere dynamics
- Astrophysical Phenomena and Observations
- Infrared Target Detection Methodologies
- Advanced Semiconductor Detectors and Materials
- Solar and Space Plasma Dynamics
- Atmospheric Ozone and Climate
- Multimodal Machine Learning Applications
- Radiation Detection and Scintillator Technologies
- African history and culture studies
- Mass Spectrometry Techniques and Applications
- Atomic and Subatomic Physics Research
- Energy Harvesting in Wireless Networks
- Optical Systems and Laser Technology
- Spectroscopy and Laser Applications
- Semantic Web and Ontologies
- Politics and Conflicts in Afghanistan, Pakistan, and Middle East
- Inertial Sensor and Navigation
University of Notre Dame
2020-2024
University of Michigan
2023-2024
University of Illinois Urbana-Champaign
2017-2023
University of Manchester
2017
In this report, we present the latest model of Gemini family, 1.5 Pro, a highly compute-efficient multimodal mixture-of-experts capable recalling and reasoning over fine-grained information from millions tokens context, including multiple long documents hours video audio. Pro achieves near-perfect recall on long-context retrieval tasks across modalities, improves state-of-the-art in long-document QA, long-video QA ASR, matches or surpasses 1.0 Ultra's performance broad set benchmarks....
Abstract We present the direct-imaging discovery of a substellar companion in orbit around Sun-like star member Hyades open cluster. So far, no other companions have been unambiguously confirmed via direct imaging main-sequence stars Hyades. The HIP 21152 is an accelerating as identified by astrometry from Gaia and Hipparcos satellites. detected companion, B, multiple epochs using high-contrast SCExAO/CHARIS Keck/NIRC2. also obtained stellar radial-velocity data Okayama 188 cm telescope....
Direct imaging of gas giant exoplanets provides information on their atmospheres and the architectures planetary systems. However, few planets have been detected in blind surveys with direct imaging. Using astrometry from Gaia Hipparcos spacecraft, we identified dynamical evidence for a planet around nearby star HIP 99770. We confirmed detection this using Subaru Coronagraphic Extreme Adaptive Optics instrument. The planet, 99770 b, orbits 17 astronomical units its host star, receiving an...
Abstract We present results from commissioning observations of the mid-IR instrument, MIRAC-5, on 6.5 m MMT telescope. MIRAC-5 is a novel ground-based instrument that utilizes state-of-the-art GeoSnap (2–13 µ m) HgCdTe detector with adaptive optics support MAPS to study protoplanetary disks, wide-orbit brown dwarfs, planetary companions in contrast-limit, and wide range other astrophysical objects. have used six engineering observing runs, improving its performance defining operating...
Abstract We present follow-up SCExAO/CHARIS H- and K -band ( R ∼ 70) high-contrast integral field spectroscopy Keck/NIRC2 photometry of directly imaged brown dwarf companion HD 33632 Ab new radial-velocity data for the system from SOPHIE spectrograph, complemented by Hipparcos Gaia astrometry. These enable more robust spectral characterization compared to lower-resolution spectra discovery paper than double available astrometric baseline. Ab’s spectrum is well reproduced a L8.5–L9.5 dwarf....
Abstract We present the direct-imaging discovery of a substellar companion (a massive planet or low-mass brown dwarf) to young, γ Doradus ( Dor)-type variable star HIP 39017 (HD 65526). The companion’s SCExAO/CHARIS JHK (1.1–2.4 μ m) spectrum and Keck/NIRC2 <?CDATA $L^{\prime} $?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>L</mml:mi> <mml:mo accent="false">′</mml:mo> </mml:math> photometry indicate that it is an L/T transition object. A comparison + L...
We present the direct-imaging discovery of a substellar companion (a massive planet or low-mass brown dwarf) to young, $\gamma$ Doradus-type variable star, HIP 39017 (HD 65526). The companion's SCExAO/CHARIS JHK ($1.1-2.4\mu$m) spectrum and Keck/NIRC2 L$^{\prime}$ photometry indicate that it is an L/T transition object. A comparison JHK+L$^{\prime}$ several atmospheric model grids finds significantly better fit cloudy models than cloudless models. Orbit modeling with relative astrometry...
We present the direct imaging discovery of a low-mass companion to nearby accelerating F star, HIP 5319, using SCExAO coupled with CHARIS, VAMPIRES, and MEC instruments in addition Keck/NIRC2 imaging. CHARIS $JHK$ (1.1-2.4 $\mu$m) spectroscopic data combined VAMPIRES 750 nm, $Y$, NIRC2 $L_{\rm p}$ photometry is best matched by an M3--M7 object effective temperature T=3200 K surface gravity log($g$)=5.5. Using relative astrometry for 5319 B from absolute primary $Gaia$ $Hipparcos$ adopting...
We present first results from a new exoplanet direct imaging survey being carried out with the Subaru Coronagraphic Extreme Adaptive Optics project coupled CHARIS integral field spectrograph. Our targeting stars showing evidence for statistically significant astrometric acceleration Hipparcos and Gaia satellites implying existence of substellar or planetary companions at sub-arcsecond separations.. JHK low-resolution spectra constrain newly-discovered companion spectral types, temperatures,...
Abstract We present the SCExAO direct imaging discovery and characterization of a low-mass companion to nearby young A7IV star, HD 91312. SCExAO/CHARIS JHK (1.1–2.4 μ m) spectra SCExAO/HiCIAO H -band identify over two year baseline in highly inclined orbit with maximum projected separation 8 au. The companion, 91312 B, induces an 8.8 σ astrometric acceleration on star as seen Gaia & Hipparcos satellites long-term radial-velocity trend previously identified by Borgniet et al. B’s spectrum...
Abstract The detailed polarization mechanisms of SiO masers originating from the near-circumstellar environment asymptotic giant branch stars are not yet definitively known. Prevailing theories broadly classified as either Zeeman or non-Zeeman in origin, latter including effects such anisotropic pumping resonant scattering. predicted behavior linear and circular fractions electric vector position angle (EVPA) vary by theory. In particular, individual maser features that exhibit a rotation ∼...
Abstract We discuss studies of polarization in astrophysical masers with particular emphasis on the case where Zeeman splitting is small compared to Doppler profile, resulting a blend transitions between magnetic substates. A semiclassical theory molecular response derived, and coupled radiative transfer solutions for 1 2-beam linear masers, set nonlinear, algebraic equations elements density matrix. The new code, PRISM, implements numerical methods compute these solutions. Using we...
We present follow-up SCExAO/CHARIS $H$ and $K$-band (R $\sim$ 70) high-contrast integral field spectroscopy Keck/NIRC2 photometry of directly-imaged brown dwarf companion HD 33632 Ab new radial-velocity data for the system from SOPHIE spectrograph, complemented by Hipparcos Gaia astrometry. These enable more robust spectral characterization compared to lower-resolution spectra discovery paper than double available astrometric baseline. Ab's spectrum is well reproduced a L8.5--L9.5 dwarf....
We describe the motivation, design, and early results for our 42-night, 125 star Subaru/SCExAO direct imaging survey planets around accelerating stars. Unlike prior large surveys, ours focuses only on stars showing evidence an astrometric acceleration plausibly due to dynamical pull of unseen planet or brown dwarf. Our program is motivated by from a recent pilot that found first jointly discovered astrometry resulted in dwarf discovery rate substantially higher than previous unbiased surveys...
New longwave HgCdTe detectors are critical to upcoming plans for ground-based infrared astronomy. These detectors, with fast-readouts and deep well-depths, will be key components of extremely large telescope instruments therefore must well understood prior deployment. We analyze one such detector, a Teledyne Imaging Sensors GeoSnap, at the University Michigan. find that properties GeoSnap consistent expectations from analysis past devices. The has well-depth 2.75 million electrons per pixel,...
ABSTRACT We present the joint astrometric and direct imaging discovery, mass measurement, orbital analysis of HD 63754 B (HIP 38216 B), a companion near stellar-substellar boundary orbiting $\sim$20 au from its Sun-like host. was observed in our ongoing high-contrast survey targeting stars with significant proper-motion accelerations between Hipparcos Gaia consistent wide-separation substellar companions. utilized archival High Resolution Echelle Spectrograph Accuracy Radial Velocity Planet...
We present results from commissioning observations of the mid-IR instrument, MIRAC-5, on 6.5-m MMT telescope. MIRAC-5 is a novel ground-based instrument that utilizes state-of-the-art GeoSnap (2 - 13 microns) HgCdTe detector with adaptive optics support MAPS to study protoplanetary disks, wide-orbit brown dwarfs, planetary companions in contrast-limit, and wide range other astrophysical objects. have used six engineering observing runs, improving its performance defining operating...
We present the joint astrometric and direct imaging discovery, mass measurement, orbital analysis of HD 63754 B (HIP 38216 B), a companion near stellar-substellar boundary orbiting ~20 AU from its Sun-like host. was observed in our ongoing high-contrast survey targeting stars with significant proper-motion accelerations between Hipparcos Gaia consistent wide-separation substellar companions. utilized archival HIRES HARPS radial velocity (RV) data, together host star's acceleration extracted...
We present first results from a new exoplanet direct imaging survey being carried out with the Subaru Coronagraphic Extreme Adaptive Optics project (SCExAO) coupled to CHARIS integral field spectrograph and assisted Keck/NIRC2, targeting stars showing evidence for an astrometric acceleration Hipparcos Gaia satellites. Near-infrared spectra thermal infrared photometry NIRC2 constrain newly-discovered companion spectral types, temperatures, gravities. Relative astrometry of companions...
CHARIS is an IFS designed for imaging and spectroscopy of disks sub-stellar companions. To improve ease use efficiency science production, we present progress on a fully-automated backend CHARIS. This Automated Data Extraction, Processing, Tracking System (ADEPTS) will log data files from in searchable database perform all calibration extraction, yielding science-grade cubes. The extracted also be run through preset array post-processing routines. With significant parallelization processing,...