Julien Lozi
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View article: SCExAO/CHARIS and Gaia Direct Imaging and Astrometric Discovery of a Superjovian Planet 3–4 <i>λ</i> / <i>D</i> from the Accelerating Star HIP 54515*
SCExAO/CHARIS and Gaia Direct Imaging and Astrometric Discovery of a Superjovian Planet 3–4 <i>λ</i> / <i>D</i> from the Accelerating Star HIP 54515* Open
We present the discovery of a superjovian planet around the young A5 star HIP 54515, detected using precision astrometry from the Hipparcos Gaia Catalogue of Accelerations and high-contrast imaging with SCExAO/CHARIS from the recently comm…
View article: OASIS Survey Direct Imaging and Astrometric Discovery of HIP 71618 B: A Substellar Companion Suitable for the Roman Coronagraph Technology Demonstration*
OASIS Survey Direct Imaging and Astrometric Discovery of HIP 71618 B: A Substellar Companion Suitable for the Roman Coronagraph Technology Demonstration* Open
We present the OASIS survey program discovery of a substellar companion orbiting the young A1V star HIP 71618, detected using precision astrometry from Gaia and Hipparcos and high-contrast imaging with SCExAO/CHARIS and Keck/NIRC2. Atmosph…
View article: Dynamical Analysis of the HD 169142 Planet-forming Disk: Twelve Years of High-contrast Polarimetry
Dynamical Analysis of the HD 169142 Planet-forming Disk: Twelve Years of High-contrast Polarimetry Open
We present a dynamical analysis of the HD 169142 planet-forming disk based on high-contrast polarimetric imaging over a twelve-year observational period, offering insights into its disk evolution and planet–disk interactions. This study ex…
View article: On-sky Demonstration of Subdiffraction-limited Astronomical Measurement Using a Photonic Lantern
On-sky Demonstration of Subdiffraction-limited Astronomical Measurement Using a Photonic Lantern Open
Resolving fine details of astronomical objects provides critical insights into their underlying physical processes. This drives in part the desire to construct ever-larger telescopes and interferometer arrays and to observe at shorter wave…
View article: Multi-band Spectral and Astrometric Characterization of the HIP 99770 b Planet with SCExAO/CHARIS and Gaia<sup>∗</sup>
Multi-band Spectral and Astrometric Characterization of the HIP 99770 b Planet with SCExAO/CHARIS and Gaia<sup>∗</sup> Open
We present and analyze follow-up, higher resolution ( R ∼ 70) H and K band integral field spectroscopy of the superjovian exoplanet HIP 99770 b with SCExAO/CHARIS. Our new data recover the companion at a high SNR in both bandpasses and mor…
View article: Unveiling the Atmosphere of HR 7672 B from the Near-infrared High-resolution Spectrum Using REACH/Subaru
Unveiling the Atmosphere of HR 7672 B from the Near-infrared High-resolution Spectrum Using REACH/Subaru Open
Characterizing the atmospheres of exoplanets and brown dwarfs is crucial for understanding their atmospheric physics and chemistry, searching for biosignatures, and investigating their formation histories. Recent advances in observational …
View article: Unveiling the Atmosphere of HR 7672 B from the Near-Infrared High-Resolution Spectrum Using REACH/Subaru
Unveiling the Atmosphere of HR 7672 B from the Near-Infrared High-Resolution Spectrum Using REACH/Subaru Open
Characterizing the atmospheres of exoplanets and brown dwarfs is crucial for understanding their atmospheric physics and chemistry, searching for biosignatures, and investigating their formation histories. Recent advances in observational …
View article: Experimental and on-sky demonstration of spectrally dispersed wavefront sensing using a photonic lantern
Experimental and on-sky demonstration of spectrally dispersed wavefront sensing using a photonic lantern Open
Adaptive optics (AO) systems are critical in any application where highly resolved imaging or beam control must be performed through a dynamic medium. Such applications include astronomy and free-space optical communications, where light p…
View article: Dynamical and Atmospheric Characterization of the Substellar Companion HD 33632 Ab from Direct Imaging, Astrometry, and Radial-velocity Data*
Dynamical and Atmospheric Characterization of the Substellar Companion HD 33632 Ab from Direct Imaging, Astrometry, and Radial-velocity Data* Open
We present follow-up SCExAO/CHARIS H- and K -band ( R ∼ 70) high-contrast integral field spectroscopy and Keck/NIRC2 photometry of directly imaged brown dwarf companion HD 33632 Ab and new radial-velocity data for the system from the SOPHI…
View article: SCExAO/CHARIS Spectroscopic Characterization of Cloudy L/T Transition Companion Brown Dwarf HIP 93398 B
SCExAO/CHARIS Spectroscopic Characterization of Cloudy L/T Transition Companion Brown Dwarf HIP 93398 B Open
Brown dwarfs with measured dynamical masses and spectra from direct imaging are benchmarks that anchor substellar atmosphere cooling and evolution models. We present Subaru SCExAO/CHARIS infrared spectroscopy of HIP 93398 B, a brown dwarf …
View article: SCExAO/CHARIS Near-infrared Scattered-light Imaging and Integral Field Spectropolarimetry of the AB Aurigae Protoplanetary System
SCExAO/CHARIS Near-infrared Scattered-light Imaging and Integral Field Spectropolarimetry of the AB Aurigae Protoplanetary System Open
We analyze near-infrared integral field spectropolarimetry of the AB Aurigae protoplanetary disk and protoplanet (AB Aur b), obtained with SCExAO/CHARIS in 22 wavelength channels covering the J , H , and K passbands ( λ 0 = 1.1–2.4 μ m) ov…
View article: Visible-light High-contrast Imaging and Polarimetry with SCExAO/VAMPIRES
Visible-light High-contrast Imaging and Polarimetry with SCExAO/VAMPIRES Open
We present significant upgrades to the Visible Aperture-Masking Polarimetric Imager/Interferometer for Resolving Exoplanetary Signatures (VAMPIRES) instrument, a visible-light (600–800 nm) high-contrast imaging polarimeter integrated withi…
View article: Visible-Light High-Contrast Imaging and Polarimetry with SCExAO/VAMPIRES
Visible-Light High-Contrast Imaging and Polarimetry with SCExAO/VAMPIRES Open
We present significant upgrades to the VAMPIRES instrument, a visible-light (600 nm to 800 nm) high-contrast imaging polarimeter integrated within SCExAO on the Subaru telescope. Key enhancements include new qCMOS detectors, coronagraphs, …
View article: SCExAO/CHARIS Near-Infrared Scattered-Light Imaging and Integral Field Spectropolarimetry of the AB Aurigae Protoplanetary System
SCExAO/CHARIS Near-Infrared Scattered-Light Imaging and Integral Field Spectropolarimetry of the AB Aurigae Protoplanetary System Open
We analyze near-infrared integral field spectropolarimetry of the AB Aurigae protoplanetary disk and protoplanet (AB Aur b), obtained with SCExAO/CHARIS in 22 wavelength channels covering the J, H, and K passbands ($λ_{\rm o}$ = 1.1--2.4 $…
View article: Design, scientific goals, and performance of the SCExAO survey for planets around accelerating stars
Design, scientific goals, and performance of the SCExAO survey for planets around accelerating stars Open
We describe the motivation, design, and early results for our 42-night, 125 star Subaru/SCExAO direct imaging survey for planets around accelerating stars. Unlike prior large surveys, ours focuses only on stars showing evidence for an astr…
View article: Spectral interferometric wavefront sensing: a solution for petalometry at Subaru/SCExAO
Spectral interferometric wavefront sensing: a solution for petalometry at Subaru/SCExAO Open
The petaling effect, induced by pupil fragmentation from the telescope spider, drastically affects the performance of high contrast instruments by inducing core splitting on the PSF. Differential piston/tip/tilt aberrations within each opt…
View article: Dynamical and Atmospheric Characterization of the Substellar Companion HD 33632 Ab from Direct Imaging, Astrometry, and Radial-Velocity Data
Dynamical and Atmospheric Characterization of the Substellar Companion HD 33632 Ab from Direct Imaging, Astrometry, and Radial-Velocity Data Open
We present follow-up SCExAO/CHARIS $H$ and $K$-band (R $\sim$ 70) high-contrast integral field spectroscopy and Keck/NIRC2 photometry of directly-imaged brown dwarf companion HD 33632 Ab and new radial-velocity data for the system from the…
View article: AO3k at Subaru: First on-sky results of the facility extreme-AO
AO3k at Subaru: First on-sky results of the facility extreme-AO Open
The facility adaptive optics of the Subaru Telescope AO188 recently received some long-awaited upgrades: a new 3224-actuator deformable mirror (DM) from ALPAO (hence the name change to AO3000 or AO3k), an upgraded GPU-based real-time compu…
View article: Searching for Protoplanets around MWC 758 and MWC 480 in Br-γ Using Kernel Phase and SCExAO/CHARIS
Searching for Protoplanets around MWC 758 and MWC 480 in Br-γ Using Kernel Phase and SCExAO/CHARIS Open
Discovering new actively accreting protoplanets is crucial to answering open questions about planet formation. However, identifying such planets at orbital distances where they are expected to be abundant is extremely challenging, both due…
View article: SCExAO/CHARIS Multiwavelength High-contrast Imaging of the BD+45<sup>°</sup>598 Debris Disk
SCExAO/CHARIS Multiwavelength High-contrast Imaging of the BD+45<sup>°</sup>598 Debris Disk Open
We present a multiwavelength (1.16–2.37 μ m) view of the debris disk around BD+45 ° 598, using the Subaru Coronagraphic Extreme Adaptive Optics system paired with the Coronagraphic High Angular Resolution Imaging Spectrograph. With an assu…
View article: Direct-imaging Discovery of a Substellar Companion Orbiting the Accelerating Variable Star HIP 39017
Direct-imaging Discovery of a Substellar Companion Orbiting the Accelerating Variable Star HIP 39017 Open
We present the direct-imaging discovery of a substellar companion (a massive planet or low-mass brown dwarf) to the young, γ Doradus ( γ Dor)-type variable star HIP 39017 (HD 65526). The companion’s SCExAO/CHARIS JHK (1.1–2.4 μ m) spectrum…
View article: Testing Magnetospheric Accretion as an Hα Emission Mechanism of Embedded Giant Planets: The Case Study for the Disk Exhibiting Meridional Flow Around HD 163296
Testing Magnetospheric Accretion as an Hα Emission Mechanism of Embedded Giant Planets: The Case Study for the Disk Exhibiting Meridional Flow Around HD 163296 Open
Recent high-sensitivity observations reveal that accreting giant planets embedded in their parental circumstellar disks can emit H α at their final formation stages. While the origin of this emission is not yet determined, magnetospheric a…
View article: Testing magnetospheric accretion as an H$α$ emission mechanism of embedded giant planets: The case study for the disk exhibiting meridional flow around HD 163296
Testing magnetospheric accretion as an H$α$ emission mechanism of embedded giant planets: The case study for the disk exhibiting meridional flow around HD 163296 Open
Recent high-sensitivity observations reveal that accreting giant planets embedded in their parental circumstellar disks can emit H$α$ at their final formation stages. While the origin of such emission is not determined yet, magnetospheric …
View article: Real-time experimental demonstrations of a photonic lantern wavefront sensor
Real-time experimental demonstrations of a photonic lantern wavefront sensor Open
The direct imaging of an Earth-like exoplanet will require sub-nanometric wavefront control across large light-collecting apertures, to reject host starlight and detect the faint planetary signal. Current adaptive optics (AO) systems, whic…
View article: Real-time Experimental Demonstrations of a Photonic Lantern Wave-front Sensor
Real-time Experimental Demonstrations of a Photonic Lantern Wave-front Sensor Open
The direct imaging of an Earth-like exoplanet will require sub-nanometric wave-front control across large light-collecting apertures to reject host starlight and detect the faint planetary signal. Current adaptive optics systems, which use…
View article: Machine-learning approach for optimal self-calibration and fringe tracking in photonic nulling interferometry
Machine-learning approach for optimal self-calibration and fringe tracking in photonic nulling interferometry Open
Photonic technologies have enabled a generation of nulling interferometers, such as the guided light interferometric nulling technology instrument, potentially capable of imaging exoplanets and circumstellar structure at extreme contrast r…
View article: Nonlinear wavefront reconstruction from a pyramid sensor using neural networks
Nonlinear wavefront reconstruction from a pyramid sensor using neural networks Open
The pyramid wavefront sensor (PyWFS) has become increasingly popular to use in adaptive optics (AO) systems due to its high sensitivity. The main drawback of the PyWFS is that it is inherently nonlinear, which means that classic linear wav…
View article: Nonlinear Wave Front Reconstruction from a Pyramid Sensor using Neural Networks
Nonlinear Wave Front Reconstruction from a Pyramid Sensor using Neural Networks Open
The pyramid wave front sensor (PyWFS) has become increasingly popular to use in adaptive optics (AO) systems due to its high sensitivity. The main drawback of the PyWFS is that it is inherently nonlinear, which means that classic linear wa…
View article: The path to detecting extraterrestrial life with astrophotonics
The path to detecting extraterrestrial life with astrophotonics Open
Astrophysical research into exoplanets has delivered thousands of confirmed planets orbiting distant stars. These planets span a wide ranges of size and composition, with diversity also being the hallmark of system configurations, the grea…
View article: 2023/05/03 VAMPIRES Zero Point Data
2023/05/03 VAMPIRES Zero Point Data Open
VAMPIRES reduced data from 2023/05/03 Behind the NIR PyWFS tests on Subaru/SCExAO. These data have been reduced with the VAMPIRES DPP and also serve as a zero point reference for "old" VAMPIRES. Note: most of this data is taken without the…