S. Mark Ammons
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View article: HD 143811 AB b: A Directly Imaged Planet Orbiting a Spectroscopic Binary in Sco-Cen
HD 143811 AB b: A Directly Imaged Planet Orbiting a Spectroscopic Binary in Sco-Cen Open
We present confirmation of HD 143811 AB b, a substellar companion to spectroscopic binary HD 143811 AB through direct imaging with the Gemini Planet Imager (GPI) and Keck NIRC2. HD 143811 AB was observed as a part of the GPI Exoplanet Surv…
View article: HD 143811 AB b: A Directly Imaged Planet Orbiting a Spectroscopic Binary in Sco-Cen
HD 143811 AB b: A Directly Imaged Planet Orbiting a Spectroscopic Binary in Sco-Cen Open
We present confirmation of HD 143811 AB b, a substellar companion to spectroscopic binary HD 143811 AB through direct imaging with the Gemini Planet Imager (GPI) and Keck NIRC2. HD 143811 AB was observed as a part of the Gemini Planet Imag…
View article: The Focal-plane Actualized Shifted Technique Realized for a Shack Hartmann Wavefront Sensor (fastrSHWFS)
The Focal-plane Actualized Shifted Technique Realized for a Shack Hartmann Wavefront Sensor (fastrSHWFS) Open
Astronomical adaptive optics (AO) is a critical approach to enable ground-based diffraction-limited imaging and high contrast science, with the potential to enable habitable exoplanet imaging on future extremely large telescopes. However, …
View article: GPI 2.0: exploring the impact of different readout modes on the wavefront sensor's EMCCD
GPI 2.0: exploring the impact of different readout modes on the wavefront sensor's EMCCD Open
The Gemini Planet Imager (GPI) is a high contrast imaging instrument that\naims to detect and characterize extrasolar planets. GPI is being upgraded to\nGPI 2.0, with several subsystems receiving a re-design to improve its contrast.\nTo en…
View article: Octofitter: Fast, Flexible, and Accurate Orbit Modeling to Detect Exoplanets
Octofitter: Fast, Flexible, and Accurate Orbit Modeling to Detect Exoplanets Open
As next-generation imaging instruments and interferometers search for planets closer to their stars, they must contend with increasing orbital motion and longer integration times. These compounding effects make it difficult to detect faint…
View article: Laboratory demonstration of the prediction of wind-blown turbulence by adaptive optics at 8 kHz with use of LQG control
Laboratory demonstration of the prediction of wind-blown turbulence by adaptive optics at 8 kHz with use of LQG control Open
The low-latency adaptive optical mirror system (LLAMAS) is designed to push the limits on achievable latencies and frame rates. It has 21 subapertures across its pupil. A reformulated version of the linear quadratic Gaussian (LQG) method p…
View article: GPI 2.0: performance evaluation of the wavefront sensor’s EMCCD
GPI 2.0: performance evaluation of the wavefront sensor’s EMCCD Open
The Gemini Planet Imager (GPI) is a high contrast imaging instrument that aims to detect and characterize extrasolar planets. GPI is being upgraded to GPI 2.0, with several subsystems receiving a re-design to improve the instrument\'s cont…
View article: Trigonometric Parallaxes of Two T Dwarfs With Keck and ShaneAO Astrometry
Trigonometric Parallaxes of Two T Dwarfs With Keck and ShaneAO Astrometry Open
We present trigonometric parallax and proper motion measurements for two T-type brown dwarfs. We derive our measurements from infrared laser guide star adaptive optics observations spanning five years from the ShaneAO/SHARCS and NIRC2/medi…
View article: GPI 2.0 : optimizing reconstructor performance in simulations and preliminary contrast estimates
GPI 2.0 : optimizing reconstructor performance in simulations and preliminary contrast estimates Open
During its move from the mountaintop of Cerro Pachon in Chile to the peak of Mauna Kea in Hawaii, the Gemini Planet Imager will make a pit stop to receive various upgrades, including a pyramid wavefront sensor. As a highly non-linear senso…
View article: Debris Disk Results from the Gemini Planet Imager Exoplanet Survey's Polarimetric Imaging Campaign
Debris Disk Results from the Gemini Planet Imager Exoplanet Survey's Polarimetric Imaging Campaign Open
We report the results of a ∼4 yr direct imaging survey of 104 stars to resolve and characterize circumstellar debris disks in scattered light as part of the Gemini Planet Imager (GPI) Exoplanet Survey. We targeted nearby (≲150 pc), young (…
View article: Processing System Design for Implementing a Linear Quadratic Gaussian (LQG) Controller to Optimize the Real-Time Correction of High Wind-Blown Turbulence
Processing System Design for Implementing a Linear Quadratic Gaussian (LQG) Controller to Optimize the Real-Time Correction of High Wind-Blown Turbulence Open
LLNL has developed a low latency, real-time, closed-loop, woofer-tweeter Adaptive Optics Control (AOC) system with a feedback control update rate of greater than 16 kHz. The Low-Latency Adaptive Mirror System (LLAMAS) is based on controlle…
View article: First Resolved Scattered-light Images of Four Debris Disks in Scorpius-Centaurus with the Gemini Planet Imager
First Resolved Scattered-light Images of Four Debris Disks in Scorpius-Centaurus with the Gemini Planet Imager Open
We present the first spatially resolved scattered-light images of four debris disks around members of the Scorpius-Centaurus (Sco-Cen) OB association with high-contrast imaging and polarimetry using the Gemini Planet Imager (GPI). All four…
View article: An Exo–Kuiper Belt with an Extended Halo around HD 191089 in Scattered Light
An Exo–Kuiper Belt with an Extended Halo around HD 191089 in Scattered Light Open
We have obtained Hubble Space Telescope STIS and NICMOS and Gemini /GPI scattered-light images of the HD 191089 debris disk. We identify two spatial components: a ring resembling the Kuiper Belt in radial extent (FWHM ∼ 25 au, centered at …
View article: The Gemini Planet Imager Exoplanet Survey: Giant Planet and Brown Dwarf Demographics from 10 to 100 au
The Gemini Planet Imager Exoplanet Survey: Giant Planet and Brown Dwarf Demographics from 10 to 100 au Open
We present a statistical analysis of the first 300 stars observed by the Gemini Planet Imager Exoplanet Survey. This subsample includes six detected planets and three brown dwarfs; from these detections and our contrast curves we infer the…
View article: The Critical, Strategic Importance of Adaptive Optics-Assisted Ground-Based Telescopes for the Success of Future NASA Exoplanet Direct Imaging Missions
The Critical, Strategic Importance of Adaptive Optics-Assisted Ground-Based Telescopes for the Success of Future NASA Exoplanet Direct Imaging Missions Open
Ground-based telescopes coupled with adaptive optics (AO) have been playing a leading role in exoplanet direct imaging science and technological development for the past two decades and will continue to have an indispensable role for the n…
View article: Dynamical Constraints on the HR 8799 Planets with GPI
Dynamical Constraints on the HR 8799 Planets with GPI Open
The HR 8799 system uniquely harbors four young super-Jupiters whose orbits can provide insights into the system’s dynamical history and constrain the masses of the planets themselves. Using the Gemini Planet Imager, we obtained down to one…
View article: Dynamical Constraints on the HR 8799 Planets with GPI
Dynamical Constraints on the HR 8799 Planets with GPI Open
The HR 8799 system uniquely harbors four young super-Jupiters whose orbits can provide insights into the system's dynamical history and constrain the masses of the planets themselves. Using the Gemini Planet Imager (GPI), we obtained down …
View article: Ground Layer Adaptive Optics for the W. M. Keck Observatory: Feasibility Study
Ground Layer Adaptive Optics for the W. M. Keck Observatory: Feasibility Study Open
Ground-layer adaptive optics (GLAO) systems offer the possibility of improving the "seeing" of large ground-based telescopes and increasing the efficiency and sensitivity of observations over a wide field-of-view. We explore the utility an…
View article: Direct Imaging of the HD 35841 Debris Disk: A Polarized Dust Ring from Gemini Planet Imager and an Outer Halo from HST/STIS
Direct Imaging of the HD 35841 Debris Disk: A Polarized Dust Ring from Gemini Planet Imager and an Outer Halo from HST/STIS Open
We present new high resolution imaging of a light-scattering dust ring and halo around the young star HD 35841. Using spectroscopic and polarimetric data from the Gemini Planet Imager in H -band (1.6 μ m), we detect the highly inclined ( i…
View article: Ground layer adaptive optics for the W. M. Keck Observatory: feasibility study
Ground layer adaptive optics for the W. M. Keck Observatory: feasibility study Open
Ground-layer adaptive optics (GLAO) systems offer the possibility of\nimproving the "seeing" of large ground-based telescopes and increasing the\nefficiency and sensitivity of observations over a wide field-of-view. We\nexplore the utility…
View article: Towards the Best Parallaxes and a Limit on the Giant Planet Occurrence Rate for Nearby T Brown Dwarfs
Towards the Best Parallaxes and a Limit on the Giant Planet Occurrence Rate for Nearby T Brown Dwarfs Open
The coldest of stars, the hottest of planets; brown dwarf stars, despite considerable data, are an enigma. Unable to fuse atomic nuclei past Deuterium, brown dwarfs are cold in temperature, and are difficult to detect with all but the most…
View article: Joint Strong and Weak Lensing Analysis of the Massive Cluster Field J0850+3604
Joint Strong and Weak Lensing Analysis of the Massive Cluster Field J0850+3604 Open
We present a combined strong and weak lensing analysis of the J085007.6+360428 (J0850) field, which contains the massive cluster Zwicky 1953. This field was selected for its high projected concentration of luminous red galaxies. Using Suba…
View article: Characterizing 51 Eri b from 1 to 5 μm: A Partly Cloudy Exoplanet
Characterizing 51 Eri b from 1 to 5 μm: A Partly Cloudy Exoplanet Open
We present spectrophotometry spanning 1–5 μ m of 51 Eridani b, a 2–10 planet discovered by the Gemini Planet Imager Exoplanet Survey. In this study, we present new K 1 (1.90–2.19 μ m) and K 2 (2.10–2.40 μ m) spectra taken with the Gemini P…
View article: Complex Spiral Structure in the HD 100546 Transitional Disk as Revealed by GPI and MagAO
Complex Spiral Structure in the HD 100546 Transitional Disk as Revealed by GPI and MagAO Open
We present optical and near-infrared high-contrast images of the transitional disk HD 100546 taken with the Magellan Adaptive Optics system (MagAO) and the Gemini Planet Imager (GPI). GPI data include both polarized intensity and total int…
View article: An Optical/Near-infrared Investigation of HD 100546 b with the Gemini Planet Imager and MagAO
An Optical/Near-infrared Investigation of HD 100546 b with the Gemini Planet Imager and MagAO Open
We present H band spectroscopic and H α photometric observations of HD 100546 obtained with the Gemini Planet Imager and the Magellan Visible AO camera. We detect H band emission at the location of the protoplanet HD 100546 b, but show tha…
View article: Integral Field Spectroscopy of the Low-mass Companion HD 984 B with the Gemini Planet Imager
Integral Field Spectroscopy of the Low-mass Companion HD 984 B with the Gemini Planet Imager Open
We present new observations of the low-mass companion to HD 984 taken with the Gemini Planet Imager (GPI) as a part of the GPI Exoplanet Survey campaign. Images of HD 984 B were obtained in the J (1.12–1.3 μ m) and H (1.50–1.80 μ m) bands.…