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AR 15048 (Archival Research)

Sun Jul 14 12:02:38 GMT 2024

Principal Investigator: Gordon Richards
PI Institution: Drexel University
Investigators (xml)

Title: Application of Independent Component Analysis to Legacy UV Quasar Spectra
Cycle: 25

Abstract
We propose to apply a novel analysis technique to UV spectroscopy of quasars in the HST archive. We endeavor to analyze all of the archival quasar spectra, but will first focus on those quasars that also have optical spectroscopy from SDSS. An archival investigation by Sulentic et al. (2007) revealed 130 known quasars with UV coverage of CIV complementing optical emission line coverage. Today, the sample has grown considerably and now includes COS spectroscopy. Our proposal includes a proof-of-concept demonstration of the power of a technique called Independent Component Analysis (ICA). ICA allows us to reduce complexity of of quasar spectra to just a handful of numbers. In addition to providing a uniform set of traditional line measurements (and carefully calibrated redshifts), we will provide ICA "weights" to the community with examples of how they can be used to do science that previously would have been quite difficult. The time is ripe for such an investigation because 1) it has been a decade since the last significant archival investigation of UV emission lines from HST quasars, 2) the future is uncertain for obtaining new UV quasar spectroscopy, and 3) the rise of machine learning has provided us with powerful new tools. Thus our proposed work will provide a true UV legacy database for quasar-based investigations.