21 papers
BOSS-CLAM: Utilizing a Constrained Linear Absorption Model to Infer Stellar Parameters from BOSS Spectra
Ilija Medan, Andrew R. Casey, Alexander P. Ji +13
Large spectroscopic surveys require robust pipelines capable of inferring stellar parameters over a wide range of the Hertzsprung-Russell (HR) diagram from data of varying quality.…
Payne4GAIN: NLTE Corrections for Red Giants in Milky Way Mapper using H-Band Neural Network Emulators
Pierre Thibodeaux, Alexander P. Ji, Nicholas Storm +12
The majority of spectroscopic surveys assume local thermodynamic equilibrium (LTE) during the modeling of stellar spectra. This assumption begins to break down for luminous stars,…
A Probabilistic Framework for Population Studies of the Solar Neighborhood: Application to SDSS-V and Gaia
Ilija Medan, Keivan G. Stassun, Zachary Way +8
Studies of the Solar Neighborhood require spectroscopic follow-up of stars identified in astrometric surveys to fully characterize their physical properties. The SDSS-V Solar Neigh…
Searching for Stellar Activity Cycles using Flares II: The TESS CVZ
Tobin M. Wainer, Holland M. Stuart, Guadalupe Tovar Mendoza +3
The paper analyzes seven years of TESS short‑cadence data for over 14,000 stars in the Continuous Viewing Zone to detect long‑term changes in flare activity, identifying 17 stars w…
Robust Heteroskedastic Matrix Factorization: A Generalization of PCA that Flags Outliers and Handles Missing Data
Thomas Hilder, David W. Hogg, Andrew R. Casey +1
We present Robust Heteroskedastic Matrix Factorization (RHMF), a generalization of Principal Component Analysis (PCA) that is robust to outliers, handles per-feature uncertainties…
A nearly pristine star from the Large Magellanic Cloud
Alexander P. Ji, Vedant Chandra, Selenna Mejias-Torres +28
The first stars formed out of pristine gas, causing them to be so massive that none are expected to have survived until today. If their direct descendants were sufficiently low-mas…