Search Publications
Likelihood-based Jump Detection and Cosmic Ray Rejection for Detectors Read Out Up-the-ramp
Brandt, Timothy D.
This paper implements likelihood-based jump detection for detectors read out up-the-ramp, using the entire set of reads to compute likelihoods. The approach compares the χ 2 value of a fit with and without a jump for every possible jump location. I show that this approach can be substantially more sensitive than one that only uses the d…
Database Design for SpExoDisks: A Database and Web Portal for Spectra of Exoplanet-forming Disks
Banzatti, Andrea; Hinkel, Natalie R.; Wheeler, Caleb H.
Data access—or the availability of new and archival data for use by the larger community—is key for scientific advancement. How data is presented, searched, and formatted determines accessibility and it can be difficult to find a solution that fits the needs of a given subdiscipline. We present a generalized roadmap for developing a specialty astr…
The Valuable Long-period Cluster Cepheid KQ Scorpii and other Calibration Candidates
Minniti, Dante; Majaess, Daniel; Turner, David G. +2 more
The classical Cepheid KQ Sco is a valuable anchor for the distance scale because of its long pulsation period ($28^{\rm d}.7$) and evidence implying membership in the open cluster UBC 1558. Analyses tied to Gaia DR3 astrometry, photometry, spectroscopy, radial velocities, and 2MASS-VVV photometry indicate a common distance of $2.15\pm0.15$ kpc (\c…
Star Image Centering with Deep Learning. II. HST/WFPC2 Full Field of View
Casetti-Dinescu, Dana I.; Girard, Terrence M.; Baena-Gallé, Roberto +2 more
We present an expanded and improved deep-learning (DL) methodology for determining centers of star images on Hubble Space Telescope/Wide-Field Planetary Camera 2 (WFPC2) exposures. Previously, we demonstrated that our DL model can eliminate the pixel-phase bias otherwise present in these undersampled images; however that analysis was limited to th…
Gen TSO: A General JWST Simulator for Exoplanet Times-series Observations
Cubillos, Patricio E.
GEN TSO is a noise calculator specifically tailored to simulate James Webb Space Telescope (JWST) time-series observations of exoplanets. GEN TSO enables the estimation of signal-to-noise ratios (S/Ns) for transit or eclipse depths through an interactive graphical interface, similar to the JWST Exposure Time Calculator (ETC). This interface levera…
ROME/REA: Three-year, Tri-color Timeseries Photometry of the Galactic Bulge
Saha, A.; Mao, S.; Zang, Weicheng +11 more
The Robotic Observations of Microlensing Events/Reactive Event Assessment Survey was a Key Project at Las Cumbres Observatory (hereafter LCO) which continuously monitored 20 selected fields (3.76 sq.deg) in the Galactic Bulge throughout their seasonal visibility window over a three-year period, between 2017 March and 2020 March. Observations were …
Enhancing Exoplanet Ephemerides by Leveraging Professional and Citizen Science Data: A Test Case with WASP-77 A b
Dalba, Paul A.; Zellem, Robert T.; Evans, Phil +42 more
We present an updated ephemeris, and physical parameters, for the exoplanet WASP-77 A b. In this effort, we combine 64 ground- and space-based transit observations, 6 space-based eclipse observations, and 32 radial velocity observations to produce this target's most precise orbital solution to date aiding in the planning of James Webb Space Telesc…
Time Variability of FUV Emission from Cool Stars on Multi-year Timescales
France, Kevin; Youngblood, Allison; Kamgar, Leo
The physical and chemical properties of planetary atmospheres are affected by temporal evolution of ultraviolet (UV) radiation inputs from their host stars at all time scales. While studies of X-ray/UV flare properties and long-term stellar evolution of exoplanet host stars have provided new constraints regarding stellar inputs to exoplanetary sys…
Optimal Fitting and Debiasing for Detectors Read Out Up-the-Ramp
Brandt, Timothy D.
This paper derives the optimal fit to a pixel's count rate in the case of an ideal detector read out nondestructively in the presence of both read and photon noise. The approach is general for any readout scheme, provides closed-form expressions for all quantities, and has a computational cost that is linear in the number of resultants (groups of …
Mid-infrared Fine Structure Lines from the Galactic Warm Ionized Medium
Kulkarni, S. R.; Beichman, Charles; Ressler, Michael E.
The Warm Ionized Medium (WIM) hosts most of the ionized gas in the Galaxy and occupies perhaps a quarter of the volume of the Galactic disk. Decoding the spectrum of the Galactic diffuse ionizing field is of fundamental interest. This can be done via direct measurements of ionization fractions of various elements. Based on current physical models …