Distributions of Galaxy Spectral Types in the Sloan Digital Sky Survey

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dc.creatorYip, Ching-Wa
dc.creatorConnolly, Andrew
dc.creatorSzalay, Alex
dc.creatorBudavari, Tamas
dc.creatorSubbaRao, Mark
dc.creatorFrieman, Joshua
dc.creatorNichol, Robert
dc.creatorHopkins, Andrew
dc.creatorYork, Donald
dc.creatorOkamura, Sadanori
dc.creatorBrinkmann, Jonathan
dc.creatorCsabai, Istvan
dc.creatorThakar, Aniruddha
dc.creatorFukugita, Masataka
dc.creatorIvezic, Zeljko
dc.date2004-07-02
dc.date2004-07-13
dc.date.accessioned2026-07-07T12:16:23Z
dc.date.available2026-07-07T12:16:23Z
dc.descriptionWe perform an objective classification of 170,000 galaxy spectra in the Sloan Digital Sky Survey (SDSS) using the Karhunen-Loève (KL) transform. With about one-sixth of the total set of galaxy spectra which will be obtained by the survey, we are able to carry out the most extensive analysis of its kind to date. The formalism proposed by Connolly and Szalay is adopted to correct for gappy regions in the spectra, and to derive eigenspectra and eigencoefficients. From this analysis, we show that this gap-correction formalism leads to a converging set of eigenspectra and KL-repaired spectra. Furthermore, KL eigenspectra of galaxies are found to be convergent not only as a function of iteration, but also as a function of the number of randomly selected galaxy spectra used in the analysis. From these data a set of ten eigenspectra of galaxy spectra are constructed, with rest-wavelength coverage 3450-8350 angstrom. The eigencoefficients describing these galaxies naturally place the spectra into several classes defined by the plane formed by the first three eigencoefficients of each spectrum. Spectral types, corresponding to different Hubble-types and galaxies with extreme emission lines, are identified for the 170,000 spectra and are shown to be complementary to existing spectral classifications. From a non-parametric classification technique, we find that the population of galaxies can be divided into three classes which correspond to early late- through to intermediate late-types galaxies. (Abridged)
dc.descriptionAJ in press (August 2004 issue) 25 pages, 24 figures (lowered resolutions). Eigenspectra and mean spectra are available in: http://www.sdss.org/dr2/products/value_added/
dc.identifierhttps://arxiv.org/abs/astro-ph/0407061
dc.identifierhttp://arxiv.org/abs/astro-ph/0407061
dc.identifierAstron.J.128:585-609,2004
dc.identifierdoi:10.1086/422429
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/211782
dc.subjectAstrophysics
dc.titleDistributions of Galaxy Spectral Types in the Sloan Digital Sky Survey
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