Search Publications
Differencing and Coadding JWST Images with Matched Point-spread Function
Wang, Lifan; Hu, Lei
We present an algorithm to derive difference images for data taken with JWST with matched point-spread functions (PSFs). It is based on the saccadic fast Fourier transform method but with revisions to accommodate the rotations and spatial variations of the PSFs. It allows for spatially varying kernels in B-spline form with separately controlled ph…
Parallax Effect in Microlensing Events Due to Free-floating Planets
Sangtarash, Parisa; Sajadian, Sedighe
One of the most important applications of microlensing observations is the detection of free-floating planets (FFPs). The timescale of microlensing due to FFPs (t E) is short (a few days). Discerning the annual parallax effect in observations of these short-duration events due to FFPs by one observer is barely possible, though their par…
Efficient Point-spread Function Modeling with ShOpt.jl: A Point-spread Function Benchmarking Study with JWST NIRCam Imaging
Casey, Caitlin M.; Kartaltepe, Jeyhan S.; Koekemoer, Anton M. +14 more
With their high angular resolutions of 30–100 mas, large fields of view, and complex optical systems, imagers on next-generation optical/near-infrared space observatories, such as the Near-Infrared Camera (NIRCam) on the James Webb Space Telescope, present new opportunities for science and also new challenges for empirical point-spread function (P…
Climbing the Cliffs: Classifying Young Stellar Objects in the Cosmic Cliffs JWST Data Using a Probabilistic Random Forest
Di Francesco, J.; Crompvoets, B. L.; Teimoorinia, H. +1 more
Among the first observations released to the public from the JWST was a section of the star-forming region NGC 3324 known colloquially as the "Cosmic Cliffs." We build a photometric catalog of the region and test the ability of using the probabilistic random forest machine-learning method to identify its young stellar objects (YSOs). We find 450 c…
Detecting Exoplanet Transits with the Next Generation of X-Ray Telescopes
Cilley, Raven; King, George W.; Corrales, Lía
Detecting exoplanet transits at X-ray wavelengths would provide a window into the effects of high-energy irradiation on the upper atmospheres of planets. However, stars are relatively dim in the X-ray, making exoplanet transit detections difficult with current X-ray telescopes. To date, only one exoplanet (HD 189733 b) has an X-ray transit detecti…
Confirmation and Characterization of the Eccentric, Warm Jupiter TIC 393818343 b with a Network of Citizen Scientists
Gagliano, Robert; Kristiansen, Martti H.; LaCourse, Daryll M. +21 more
NASA's Transiting Exoplanet Survey Satellite (TESS) has identified over 7000 candidate exoplanets via the transit method, with gas giants among the most readily detected due to their large radii. Even so, long intervals between TESS observations for much of the sky lead to candidates for which only a single transit is detected in one TESS sector, …
Discovery of a Bow-shock Nebula Around the Z Cam-type Cataclysmic Variable SY Cancri
Bond, Howard E.; Talbot, Jonathan; Carter, Calvin +3 more
We report the serendipitous discovery of a bow-shock nebula around the cataclysmic variable (CV) SY Cancri. In addition, SY Cnc lies near the edge of a faint Hα-emitting nebula with a diameter of about
Photometric Completeness Modelled with Neural Networks
Speagle, Joshua S.; Harris, William E.
In almost any study involving optical/near-infrared photometry, understanding the completeness of detection and recovery is an essential part of the work. The recovery fraction is, in general, a function of several variables including magnitude, color, background sky noise, and crowding. We explore how completeness can be modeled, with the use of …
Singular Spectrum Analysis of Exoplanetary Transits
Sajadian, Sedighe; Fatheddin, Hossein
Transit photometry is currently the most efficient and sensitive method for detecting extrasolar planets (exoplanets) and a large majority of confirmed exoplanets have been detected with this method. The substantial success of space-based missions such as NASA's Kepler/K2 and Transiting Exoplanet Survey Satellite has generated a large and diverse …
Dynamical Mass of the Ophiuchus Intermediate-mass Stellar System S1 with DYNAMO-VLBA
Dupuy, Trent J.; Rodríguez, Luis F.; Loinard, Laurent +8 more
We report dynamical mass measurements of the individual stars in the most luminous and massive stellar member of the nearby Ophiuchus star-forming region, the young tight binary system S1. We combine 28 archival data sets with seven recent proprietary Very Long Baseline Array (VLBA) observations obtained as part of the Dynamical Masses of Young St…