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Using Non-negative Matrix Factorization to Improve Calibration of the Keck OSIRIS Integral Field Spectrograph

Horstman, Katelyn and Fitzgerald, Michael P. and Lyke, James E. and Yeh, Sherry C. C. and Chu, Devin S. (2022) Using Non-negative Matrix Factorization to Improve Calibration of the Keck OSIRIS Integral Field Spectrograph. Publications of the Astronomical Society of the Pacific, 134 (1036). Art. No. 064504. ISSN 0004-6280. doi:10.1088/1538-3873/ac7905.

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Integral Field Spectrographs (IFS) often require non-trivial calibration techniques to process raw data. The OH Suppressing InfraRed Imaging Spectrograph at the W. M. Keck Observatory is a lenslet-based IFS that requires precise methods to associate the flux on the detector with both a wavelength and a position on the detector. During calibration scans, a single column lenslet mask is utilized to keep light from adjacent lenslet columns separate from the primary lenslet column, in order to uniquely determine spectral response of individual lenslets on the detector. Despite employing a single column lenslet mask, an issue associated with such calibration schemes may occur when light from adjacent masked lenslet columns leaks into the primary lenslet column. Incorrectly characterizing the flux due to additional light in the primary lenslet column results in one form of crosstalk between lenslet columns, which most clearly manifest as non-physical artifacts in the spectral dimension of the reduced data. We treat the problem of potentially blended calibration scans as a source separation problem and implement Non-negative Matrix Factorization (NMF) as a way to separate blended calibration scan spectra. After applying NMF to calibration scan data, extracted spectra from calibration scans show reduced crosstalk of up to 26.7% ± 0.5% while not adversely impacting the signal-to-noise ratio. Additionally, we determined the optimal number of calibration scans per lenslet column needed to create NMF factors, finding that greatest reduction crosstalk occurs when NMF factors are created using one calibration scan per lenslet column.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Horstman, Katelyn0000-0001-9708-8667
Fitzgerald, Michael P.0000-0002-0176-8973
Lyke, James E.0000-0001-7809-7867
Yeh, Sherry C. C.0000-0002-4037-3114
Chu, Devin S.0000-0003-3765-8001
Additional Information:© 2022. The Astronomical Society of the Pacific. Received 2022 April 5; accepted 2022 June 9; published 2022 June 29. The authors would like to thank the OSIRIS working group for their involvement and feedback throughout the duration of this project. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors also wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.
Funding AgencyGrant Number
W. M. Keck FoundationUNSPECIFIED
Subject Keywords:Flux calibration; Astronomical instrumentation
Issue or Number:1036
Classification Code:Unified Astronomy Thesaurus concepts: Flux calibration (544); Astronomical instrumentation (799)
Record Number:CaltechAUTHORS:20220715-744434000
Persistent URL:
Official Citation:Katelyn Horstman et al 2022 PASP 134 064504
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:115654
Deposited By: George Porter
Deposited On:18 Jul 2022 17:41
Last Modified:18 Jul 2022 17:41

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