arXiv subjects

Katie M. Morzinski

Publications and source records attributed to Katie M. Morzinski.

At least 19 recordsLinked to original sources

arXiv2025

Five New Sirius-Like White Dwarf + Main Sequence Star Systems with MagAO-X

Most known white dwarfs in multiple systems with main sequence stars have been discovered with M-type companions, because the white dwarf causes detectable UV excess and bluer colors than expected from a single M star. Surveys have shown that the number of white dwarfs in Sirius-like systems within 100 pc of the Sun is lower than expected, suggesting that white dwarfs are being missed in the glare of their main sequence companions. In this work we have leveraged the angular resolution and high-contrast capabilities, as well as optimization for visible wavelengths, of the extreme adaptive optics instrument MagAO-X to detect new white dwarf companions to AFGK stars. We present the first results of our survey with the extreme AO instrument MagAO-X, called the Pup Search, of 18 targets with seven new candidate companions, five of which are confirmed to be white dwarfs. We discuss the new detections in the context of previous surveys and other detection metric sensitivities and show that we are sensitive to a region not probed by other surveys. Finally we discuss the future of the Pup Search in light of developing technologies.

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arXiv2024

Tuning the MAPS Adaptive Secondary Mirror: Actuator Control, PID Tuning, Power Spectra and Failure Diagnosis

The MMT Adaptive optics exoPlanet characterization System (MAPS) is currently in its engineering phase, operating on-sky at the MMT Telescope on Mt. Hopkins in southern Arizona. The MAPS Adaptive Secondary Mirror's actuators are controlled by a closed loop modified PID control law and an open loop feed-forward law, which in combination allows for faster actuator response time. An essential element of achieving the secondary's performance goals involves the process of PID gain tuning. To start, we briefly discuss the design of the MAPS ASM and its actuators. We then describe the actuator positional control system and control law. Next, we discuss a few of the issues that make ASM tuning difficult. We then outline our initial attempts at tuning the actuator controllers and discuss the use of actuator positional power spectra for both tuning and determining the health and failure states of individual actuators. We conclude by presenting the results of our latest round of tuning configuration trials, which have been successful at decreasing mirror latency, increasing operational mirror modes and improving image PSF.

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arXiv2024

ESCAPE: Efficient Synthesis of Calibrations for Adaptive optics through Pseudo-synthetic and Empirical methods

With the commissioning of the refurbished adaptive secondary mirror (ASM) for the 6.5-meter MMT Observatory under way, special consideration had to be made to properly calibrate the mirror response functions to generate an interaction matrix (IM). The commissioning of the ASM is part of the MMT Adaptive optics exoPlanet characterization System (MAPS) upgrade the observatory's legacy adaptive optics (AO) system. Unlike most AO systems, MAPS employs a convex ASM which prevents the introduction of a calibration source capable of simultaneously illuminating its ASM and wavefront sensor (WFS). This makes calibration of the AO system a significant hurdle in commissioning. To address this, we have employed a hybrid calibration strategy we call the Efficient Synthesis of Calibrations for Adaptive Optics through Pseudo-synthetic and Empirical methods (ESCAPE). ESCAPE combines the DO-CRIME on-sky calibration method with the SPRINT method for computing pseudo-synthetic calibration matrices. To monitor quasi-static system change, the ESCAPE methodology rapidly and continuously generates pseudo-synthetic calibration matrices using continual empirical feedback in either open or closed-loop. In addition, by measuring the current IM in the background while in close-loop, we are also able to measure the optical gains for pyramid wavefront sensor (PyWFS) systems. In this paper, we will provide the mathematical foundation of the ESCAPE calibration strategy and on-sky results from its application in calibrating the MMT Observatory's ASM. Additionally, we will showcase the validation of our approach from our AO testbed and share preliminary on-sky results from MMT.

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arXiv2023

Probing Disk Ice Content and PAH Emission Through Multiband MagAO+Clio Images of HD 141569

We present resolved images of the inner disk component around HD 141569 using the Magellan adaptive optics system with the Clio2 1 - 5 $μ$m camera, offering a glimpse of a complex system thought to be in a short evolutionary phase between protoplanetary and debris disk stages. We use a reference star along with the KLIP algorithm for PSF subtraction to detect the disk inward to about 0.24" (~25 au assuming a distance of 111 pc) at high signal-to-noise ratios at $L'$ (3.8 $μ$m), $Ls$ (3.3 $μ$m), and narrowband $Ice$ (3.1 $μ$m). We identify an arc or spiral arm structure at the southeast extremity, consistent with previous studies. We implement forward modeling with a simple disk model within the framework of an MCMC sampler to better constrain the geometrical attributes and photometry using our KLIP-reduced disk images. We then leverage these modeling results to facilitate a comparison of the measured brightness in each passband to find a reduction in scattered light from the disk in the $Ice$ filter, implying significant absorption due to water ice in the dust. Additionally, our best-fit disk models exhibit peak brightness in the southwestern, back-scattering region of the disk, which we suggest to be possible evidence of 3.3 $μ$m PAH emission. However, we point out the need for additional observations with bluer filters and more complex modeling to confirm these hypotheses.

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arXiv2023

Applying a temporal systematics model to vector Apodizing Phase Plate coronagraphic data: TRAP4vAPP

The vector Apodizing Phase Plate (vAPP) is a pupil plane coronagraph that suppresses starlight by forming a dark hole in its point spread function (PSF). The unconventional and non-axisymmetrical PSF arising from the phase modification applied by this coronagraph presents a special challenge to post-processing techniques. We aim to implement a recently developed post-processing algorithm, temporal reference analysis of planets (TRAP) on vAPP coronagraphic data. The property of TRAP that uses non-local training pixels, combined with the unconventional PSF of vAPP, allows for more flexibility than previous spatial algorithms in selecting reference pixels to model systematic noise. Datasets from two types of vAPPs are analysed: a double grating-vAPP (dgvAPP360) that produces a single symmetric PSF and a grating-vAPP (gvAPP180) that produces two D-shaped PSFs. We explore how to choose reference pixels to build temporal systematic noise models in TRAP for them. We then compare the performance of TRAP with previously implemented algorithms that produced the best signal-to-noise ratio (S/N) in companion detections in these datasets. We find that the systematic noise between the two D-shaped PSFs is not as temporally associated as expected. Conversely, there is still a significant number of systematic noise sources that are shared by the dark hole and the bright side in the same PSF. We should choose reference pixels from the same PSF when reducing the dgvAPP360 dataset or the gvAPP180 dataset with TRAP. In these datasets, TRAP achieves results consistent with previous best detections, with an improved S/N for the gvAPP180 dataset.

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arXiv2023

The Giant Accreting Protoplanet Survey (GAPlanetS) -- Results from a Six Year Campaign to Image Accreting Protoplanets

Accreting protoplanets represent a window into planet formation processes. We report Hα differential imaging results from the deepest and most comprehensive accreting protoplanet survey to date, acquired with the Magellan Adaptive Optics (MagAO) system's VisAO camera. The fourteen transitional disks targeted are ideal candidates for protoplanet discovery due to their wide, heavily depleted central cavities, wealth of non-axisymmetric circumstellar disk features evocative of ongoing planet formation, and ongoing stellar accretion. To address the twin challenges of morphological complexity in the target systems and PSF instability, we develop novel approaches for frame selection and optimization of the Karhounen-Loeve Image Processing algorithm pyKLIP. We detect one new candidate protoplanet, CS Cha "c", at a separation of 75mas and a Delta mag of 5.1 and robustly recover the HD142527 B and HD100453 B low mass stellar companions across multiple epochs. Though we cannot rule out a substantial scattered light contribution to its emission, we also recover LkCa 15 b. Its presence inside of the cleared disk cavity and consistency with a forward-modeled point source suggest that it remains a viable protoplanet candidate. The protoplanet PDS 70 c was marginally recovered under our conservative general methodology. However, through targeted optimization in H-alpha} imagery, we tentatively recover PDS 70 c in three epochs and PDS 70 b in one epoch. Of the many other previously-reported companions and companion candidates around objects in the sample, we do not recover any additional robust candidates. However, lack of recovery at moderate H-alpha contrast does not rule out the presence of protoplanets at these locations, and we report limiting H-alpha contrasts in such cases.

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arXiv2023

HIP 67506 C: MagAO-X Confirmation of a New Low-Mass Stellar Companion to HIP 67506 A

We report the confirmation of HIP 67506 C, a new stellar companion to HIP 67506 A. We previously reported a candidate signal at 2$λ$/D (240~mas) in L$^{\prime}$ in MagAO/Clio imaging using the binary differential imaging technique. Several additional indirect signals showed that the candidate signal merited follow-up: significant astrometric acceleration in Gaia DR3, Hipparcos-Gaia proper motion anomaly, and overluminosity compared to single main sequence stars. We confirmed the companion, HIP 67506 C, at 0.1" with MagAO-X in April, 2022. We characterized HIP 67506 C MagAO-X photometry and astrometry, and estimated spectral type K7-M2; we also re-evaluated HIP 67506 A in light of the close companion. Additionally we show that a previously identified 9" companion, HIP 67506 B, is a much further distant unassociated background star. We also discuss the utility of indirect signposts in identifying small inner working angle candidate companions.

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arXiv2023

Improved companion mass limits for Sirius A with thermal infrared coronagraphy using a vector-apodizing phase plate and time-domain starlight-subtraction techniques

We use observations with the infrared-optimized MagAO system and Clio camera in 3.9 $μ$m light to place stringent mass constraints on possible undetected companions to Sirius A. We suppress the light from Sirius A by imaging it through a grating vector-apodizing phase plate coronagraph with 180-degree dark region (gvAPP-180). To remove residual starlight in post-processing, we apply a time-domain principal-components-analysis-based algorithm we call PCA-Temporal (PCAT), which uses eigen-time-series rather than eigen-images to subtract starlight. By casting the problem in terms of eigen-time-series, we reduce the computational cost of post-processing the data, enabling the use of the fully sampled dataset for improved contrast at small separations. We also discuss the impact of retaining fine temporal sampling of the data on final contrast limits. We achieve post-processed contrast limits of $1.5 \times 10^{-6}$ to $9.8 \times 10^{-6}$ outside of 0.75 arcsec which correspond to planet masses of 2.6 to 8.0 $M_J$. These are combined with values from the recent literature of high-contrast imaging observations of Sirius to synthesize an overall completeness fraction as a function of mass and separation. After synthesizing these recent studies and our results, the final completeness analysis rules out 99% of $\ge 9 \ M_J$ planets from 2.5-7 AU.

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arXiv2022

Improved Orbital Constraints and H$α$ Photometric Monitoring of the Directly Imaged Protoplanet Analog HD 142527 B

Companions embedded in the cavities of transitional circumstellar disks have been observed to exhibit excess luminosity at H$α$, an indication that they are actively accreting. We report 5 years (2013-2018) of monitoring of the position and H$α$ excess luminosity of the embedded, accreting low-mass stellar companion HD 142527 B from the MagAO/VisAO instrument. We use pyklip, a python implementation of the Karhounen-Loeve Image Processing algorithm, to detect the companion. Using pyklip forward modeling, we constrain the relative astrometry to $1-2 \mathrm{mas}$ precision and achieve sufficient photometric precision ($\pm0.2 \mathrm{mag}, 3\%$ error) to detect changes in the H$α$ contrast of the companion over time. In order to accurately determine the relative astrometry of the companion, we conduct an astrometric calibration of the MagAO/VisAO camera against 20 years of Keck/NIRC2 images of the Trapezium cluster. We demonstrate agreement of our VisAO astrometry with other published positions for HD 142527 B, and use orbitize! to generate a posterior distribution of orbits fit to the relative astrometry of HD 142527 B. Our data suggest that the companion is close to periastron passage, on an orbit significantly misinclined with respect to both the wide circumbinary disk and the recently observed inner disk encircling HD 142527 A. We translate observed H-alpha contrasts for HD 142527 B into mass accretion rate estimates on the order of $4-9\times10^{-10} \mathrm{M_\odot}\mathrm{yr}^{-1}$. Photometric variation in the H-alpha excess of the companion suggests that the accretion rate onto the companion is variable. This work represents a significant step towards observing accretion-driven variability onto protoplanets, such as PDS 70 bc.

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arXiv2022

The Giant Accreting Protoplanet Survey (GAPlanetS): Optimization Techniques for Robust Detections of Protoplanets

High-contrast imaging has afforded astronomers the opportunity to study light directly emitted by adolescent (tens of Myr) and ``proto" ($<$10Myr) planets still undergoing formation. Direct detection of these planets is enabled by empirical Point Spread Function (PSF) modeling and removal algorithms. The computational intensity of such algorithms, and their multiplicity of tunable input parameters, has led to the prevalence of ad-hoc optimization approaches to high-contrast imaging results. In this work, we present a new, systematic approach to optimization vetted using data of the high-contrast stellar companion HD 142527 B from the Magellan Adaptive Optics (MagAO) Giant Accreting Protoplanet Survey (GAPlanetS). More specifically, we present a grid search technique designed to explore three influential parameters of the PSF-subtraction algorithm pyKLIP -- annuli, movement, and KL modes. We consider multiple metrics for post-processed image quality in order to optimally recover at H$α$ (656nm) synthetic planets injected into contemporaneous continuum (643nm) images. These metrics include: peak (single-pixel) SNR, average (multi-pixel average) SNR, 5$σ$ contrast, and false-positive fraction. We apply continuum-optimized KLIP reduction parameters to six H$α$ direct detections of the low-mass stellar companion HD142527 B, and recover the companion at a range of separations. Relative to a single-informed, non-optimized set of KLIP parameters applied to all datasets uniformly, our multi-metric grid search optimization led to improvements in companion SNR of up to 1.2$σ$, with an average improvement of 0.6$σ$. Since many direct imaging detections lie close to the canonical 5$σ$ threshold, even such modest improvements may result in higher yields in future imaging surveys.

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arXiv2022

XPipeline: Starlight subtraction at scale for MagAO-X

MagAO-X is an extreme adaptive optics (ExAO) instrument for the Magellan Clay 6.5-meter telescope at Las Campanas Observatory in Chile. Its high spatial and temporal resolution can produce data rates of 1 TB/hr or more, including all AO system telemetry and science images. We describe the tools and architecture we use for commanding, telemetry, and science data transmission and storage. The high data volumes require a distributed approach to data processing, and we have developed a pipeline that can scale from a single laptop to dozens of HPC nodes. The same codebase can then be used for both quick-look functionality at the telescope and for post-processing. We present the software and infrastructure we have developed for ExAO data post-processing, and illustrate their use with recently acquired direct-imaging data.

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arXiv2022

Companion Mass Limits for 17 Binary Systems Obtained with Binary Differential Imaging and MagAO/Clio

Improving direct detection capability close to the star through improved star-subtraction and post-processing techniques is vital for discovering new low-mass companions and characterizing known ones at longer wavelengths. We present results of 17 binary star systems observed with the Magellan Adaptive Optics system (MagAO) and the Clio infrared camera on the Magellan Clay Telescope using Binary Differential Imaging (BDI). BDI is an application of Reference Differential Imaging (RDI) and Angular Differential Imaging (ADI) applied to wide binary star systems (2\arcsec $<Δρ<$ 10\arcsec) within the isoplanatic patch in the infrared. Each star serves as the point-spread-function (PSF) reference for the other, and we performed PSF estimation and subtraction using Principal Component Analysis. We report contrast and mass limits for the 35 stars in our initial survey using BDI with MagAO/Clio in L$^\prime$ and 3.95$μ$m bands. Our achieved contrasts varied between systems, and spanned a range of contrasts from 3.0-7.5 magnitudes and a range of separations from 0.2\arcsec to $\sim$2\arcsec. Stars in our survey span a range of masses, and our achieved contrasts correspond to late-type M dwarf masses down to $\sim$10 M$_{\rm{jup}}$. We also report detection of a candidate companion signal at 0.2\arcsec (18 AU) around HIP 67506 A (SpT G5V, mass $\sim$1.2\Msun), which we estimate to be ~60-90 M$_{\rm{jup}}$. We found that the effectiveness of BDI is highest for approximately equal brightness binaries in high-Strehl conditions.

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arXiv2022

High contrast imaging with Fizeau interferometry: The case of Altair

The Large Binocular Telescope (LBT) has two 8.4-m primary mirrors that produce beams that can be combined coherently in a "Fizeau" interferometric mode. In principle, the Fizeau PSF enables the probing of structure at a resolution up to three times better than that of the adaptive-optics-corrected PSF of a single 8.4-m telescope. In this work, we examined the nearby star Altair (5.13 pc, type A7V, $\sim$100s Myr to $\approx$1.4 Gyr) in the Fizeau mode with the LBT at Br-$α$ (4.05 $μ$m) and carried out angular differential imaging to search for companions. This work presents the first filled-aperture LBT Fizeau science dataset to benefit from a correcting mirror which provides active phase control. In the analysis of the $λ/D$ angular regime, the sensitivity of the dataset is down to $\approx$0.5 $M_{\odot}$ at 1" for a 1.0 Gyr system. This sensitivity remains limited by the small amount of integration time, which is in turn limited by the instability of the Fizeau PSF. However, in the Fizeau fringe regime we attain sensitivities of $Δm \approx 5$ at 0.2" and put constraints to companions of 1.3 $M_{\odot}$ down to an inner angle of $\approx$0.15", closer than any previously published direct imaging of Altair. This analysis is a pathfinder for future datasets of this type, and represents some of the first steps to unlocking the potential of the first ELT. Fizeau observations will be able to reach dimmer targets with upgrades to the instrument, in particular the phase detector.

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arXiv2021

Characterizing microlensing planetary system OGLE-2014-BLG-0676Lb with adaptive optics imaging

We constrain the host-star flux of the microlensing planet OGLE-2014-BLG-0676Lb using adaptive optics (AO) images taken by the Magellan and Keck telescopes. We measure the flux of the light blended with the microlensed source to be K = 16.79 +/- 0.04 mag and J = 17.76 +/- 0.03 mag. Assuming that the blend is the lens star, we find that the host is a $0.73_{-0.29}^{+0.14}$ M_Sun star at a distance of $2.67_{-1.41}^{+0.77}$ kpc, where the relatively large uncertainty in angular Einstein radius measurement is the major source of uncertainty. With mass of $M_p = 3.68_{-1.44}^{+0.69}$ M_J, the planet is likely a "super Jupiter" at a projected separation of $r_{\perp} = 4.53_{-2.50}^{+1.49}$ AU, and a degenerate model yields a similar $M_p = 3.73_{-1.47}^{+0.73}$ M_J at a closer separation of $r_{\perp} = 2.56_{-1.41}^{+0.84}$ AU. Our estimates are consistent with the previous Bayesian analysis based on a Galactic model. OGLE-2014-BLG-0676Lb belongs to a sample of planets discovered in a "second-generation" planetary microlensing survey, and we attempt to systematically constrain host properties of this sample with high-resolution imaging to study the distribution of planets.

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arXiv2021

Characterizing deformable mirrors for the MagAO-X instrument

The MagAO-X instrument is a new extreme adaptive optics system for high-contrast imaging at visible and near-infrared wavelengths on the Magellan Clay Telescope. A central component of this system is a 2040-actuator microelectromechanical deformable mirror (DM) from Boston Micromachines Corp. that operates at 3.63 kHz for high-order wavefront control (the tweeter). Two additional DMs from ALPAO perform the low-order (the woofer) and non-common-path science-arm wavefront correction (the NCPC DM). Prior to integration with the instrument, we characterized these devices using a Zygo Verifire Interferometer to measure each DM surface. We present the results of the characterization effort here, demonstrating the ability to drive tweeter to a flat of 6.9 nm root mean square (RMS) surface (and 0.56 nm RMS surface within its control bandwidth), the woofer to 2.2 nm RMS surface, and the NCPC DM to 2.1 nm RMS surface over the MagAO-X beam footprint on each device. Using focus-diversity phase retrieval on the MagAO-X science cameras to estimate the internal instrument wavefront error (WFE), we further show that the integrated DMs correct the instrument WFE to 18.7 nm RMS, which, combined with a 11.7% pupil amplitude RMS, produces a Strehl ratio of 0.94 at H$α$.

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arXiv2021

High-contrast observations of brown dwarf companion HR 2562 B with the vector Apodizing Phase Plate coronagraph

The vector Apodizing Phase Plate (vAPP) is a class of pupil plane coronagraph that enables high-contrast imaging by modifying the Point Spread Function (PSF) to create a dark hole of deep flux suppression adjacent to the PSF core. Here, we recover the known brown dwarf HR 2562 B using a vAPP coronagraph, in conjunction with the Magellan Adaptive Optics (MagAO) system, at a signal-to-noise of S/N = 3.04 in the lesser studied L-band regime. The data contained a mix of field and pupil-stabilised observations, hence we explored three different processing techniques to extract the companion, including Flipped Differential Imaging (FDI), a newly devised Principal Component Analysis (PCA)-based method for vAPP data. Despite the partial field-stabilisation, the companion is recovered sufficiently to measure a 3.94 $μ$m narrow-band contrast of (3.05$\pm$1.00) $\times$ 10$^{-4}$ ($Δ$m$_{3.94 μm}$ = 8.79$\pm$0.36 mag). Combined with archival GPI and SPHERE observations, our atmospheric modelling indicates a spectral type at the L/T transition with mass M = 29$\pm$15 M$_{\text{Jup}}$, consistent with literature results. However, effective temperature and surface gravity vary significantly depending on the wavebands considered (1200$\leq$T$_{\text{eff}}$(K)$\leq$1700 and 4.0$\leq$log(g)(dex)$\leq$5.0), reflecting the challenges of modelling objects at the L/T transition. Observations between 2.4-3.2 $μ$m will be more effective in distinguishing cooler brown dwarfs due to the onset of absorption bands in this region. We explain that instrumental scattered light and wind-driven halo can be detrimental to FDI+PCA and thus must be sufficiently mitigated to use this processing technique. We thus demonstrate the potential of vAPP coronagraphs in the characterisation of high-contrast substellar companions, even in sub-optimal conditions, and provide new, complementary photometry of HR 2562 B.

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arXiv2020

Design and development of a high-speed Visible Pyramid Wavefront Sensor for the MMT AO system

MAPS, MMT Adaptive optics exoPlanet characterization System, is the upgrade of legacy 6.5m MMT adaptive optics system. It is an NSF MSIP-funded project that includes (i) refurbishing of the MMT Adaptive Secondary Mirror (ASM), (ii) new high sensitive and high spatial order visible and near-infrared pyramid wavefront sensors, and (iii) the upgrade of Arizona Infrared Imager and Echelle Spectrograph (ARIES) and MMT high Precision Imaging Polarimeter (MMTPol) science cameras. This paper will present the design and development of the visible pyramid wavefront sensor. This system consists of an acquisition camera, a fast-steering tip-tilt modulation mirror, a double pyramid, a pupil imaging triplet lens, and a low noise and high-speed frame rate based CCID75 camera. We will report on hardware and software and present the laboratory characterization results of the individual subsystems, and outline the on-sky commissioning plan.

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arXiv2020

OGLE-2007-BLG-224L: Confirmation of Terrestrial Parallax

We present limits on the lens flux of OGLE-2007-BLG-224 based on MagAO imaging taken seven years after the microlensing event. At the time of the observations, the lens should have been separated from the microlensing source by 292 mas. However, no new sources are detected with MagAO. We place an upper limit on the lens flux of $H>20.57$. This measurement supports the conclusion of Gould et al. (2009) that the lens in this event should be a brown dwarf. This is the first test of a prediction based on the terrestrial microlens parallax effect and the first AO confirmation of a sub-stellar/dark microlens.

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