Objective identification of informative wavelength regions in galaxy spectra

Ching Wa Yip, Michael W. Mahoney, Alexander S. Szalay, I. Csabai, Tamás Budavári, Rosemary F G Wyse, Laszlo Dobos

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Understanding the diversity in spectra is the key to determining the physical parameters of galaxies. The optical spectra of galaxies are highly convoluted with continuum and lines that are potentially sensitive to different physical parameters. Defining the wavelength regions of interest is therefore an important question. In this work, we identify informative wavelength regions in a single-burst stellar population model using the CUR Matrix Decomposition. Simulating the Lick/IDS spectrograph configuration, we recover the widely used Dn (4000), Hβ, and HδA to be most informative. Simulating the Sloan Digital Sky Survey spectrograph configuration with a wavelength range 3450-8350 Å and a model-limited spectral resolution of 3 Å, the most informative regions are: first region - the 4000 Å break and the Hδ line; second region - the Fe-like indices; third region - the Hβ line; and fourth region - the G band and the Hγ line. A principal component analysis on the first region shows that the first eigenspectrum tells primarily the stellar age, the second eigenspectrum is related to the age-metallicity degeneracy, and the third eigenspectrum shows an anti-correlation between the strengths of the Balmer and the Ca K and H absorptions. The regions can be used to determine the stellar age and metallicity in early-type galaxies that have solar abundance ratios, no dust, and a single-burst star formation history. The region identification method can be applied to any set of spectra of the user's interest, so that we eliminate the need for a common, fixed-resolution index system. We discuss future directions in extending the current analysis to late-type galaxies. ASCII formatted tables of the regional eigenspectra are available.

Original languageEnglish
Article number110
JournalAstronomical Journal
Volume147
Issue number5
DOIs
Publication statusPublished - 2014

Fingerprint

H lines
galaxies
wavelength
wavelengths
spectrographs
metallicity
bursts
principal components analysis
configurations
spectral resolution
optical spectrum
star formation
dust
histories
continuums
decomposition
identification method
matrices
principal component analysis
matrix

Keywords

  • galaxies: fundamental parameters
  • methods: data analysis

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Yip, C. W., Mahoney, M. W., Szalay, A. S., Csabai, I., Budavári, T., Wyse, R. F. G., & Dobos, L. (2014). Objective identification of informative wavelength regions in galaxy spectra. Astronomical Journal, 147(5), [110]. https://doi.org/10.1088/0004-6256/147/5/110

Objective identification of informative wavelength regions in galaxy spectra. / Yip, Ching Wa; Mahoney, Michael W.; Szalay, Alexander S.; Csabai, I.; Budavári, Tamás; Wyse, Rosemary F G; Dobos, Laszlo.

In: Astronomical Journal, Vol. 147, No. 5, 110, 2014.

Research output: Contribution to journalArticle

Yip, CW, Mahoney, MW, Szalay, AS, Csabai, I, Budavári, T, Wyse, RFG & Dobos, L 2014, 'Objective identification of informative wavelength regions in galaxy spectra', Astronomical Journal, vol. 147, no. 5, 110. https://doi.org/10.1088/0004-6256/147/5/110
Yip, Ching Wa ; Mahoney, Michael W. ; Szalay, Alexander S. ; Csabai, I. ; Budavári, Tamás ; Wyse, Rosemary F G ; Dobos, Laszlo. / Objective identification of informative wavelength regions in galaxy spectra. In: Astronomical Journal. 2014 ; Vol. 147, No. 5.
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