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dc.contributor.authorRogers, B.
dc.contributor.authorFerreras, I.
dc.contributor.authorLahav, O.
dc.contributor.authorBernardi, M.
dc.contributor.authorKaviraj, S.
dc.contributor.authorYi, S.K.
dc.date.accessioned2013-10-30T12:00:54Z
dc.date.available2013-10-30T12:00:54Z
dc.date.issued2007-12-01
dc.identifier.citationRogers , B , Ferreras , I , Lahav , O , Bernardi , M , Kaviraj , S & Yi , S K 2007 , ' Decoding the spectra of SDSS early-type galaxies : New indicators of age and recent star formation ' , Monthly Notices of the Royal Astronomical Society , vol. 382 , no. 2 , pp. 750-760 . https://doi.org/10.1111/j.1365-2966.2007.12446.x
dc.identifier.issn0035-8711
dc.identifier.otherPURE: 2065585
dc.identifier.otherPURE UUID: f4324169-feba-4de5-ad7b-62fe1cb7254d
dc.identifier.otherScopus: 36348953351
dc.identifier.otherORCID: /0000-0002-5601-575X/work/77850144
dc.identifier.urihttp://hdl.handle.net/2299/11925
dc.description.abstractWe apply principal component analysis (PCA) to a sample of early-type galaxies from the Sloan Digital Sky Survey (SDSS) in order to infer differences in their star formation histories from their unresolved stellar populations. We select a z <0.1 volume-limited sample comprising ∼7000 early-type galaxies from SDSS/Data Release 4. Out of the first few principal components (PC), we study four which give information about stellar populations and velocity dispersion. We construct two parameters (η and ζ) as linear combinations of PC1 and PC2. The four components can be presented as 'optimal filters' to explore in detail the properties of the underlying stellar populations. By comparing various photospectroscopic observables - including near-ultraviolet (NUV) photometry from Galaxy Evolution Explorer (GALEX) - we find ζ to be most sensitive to recent episodes of star formation, and η to be strongly dependent on the average age of the stellar populations. Both η and ζ also depend on metallicity. We apply these optimal filters to composite spectra assembled by Bernardi et al. The distribution of the η component of the composites appear to be indistinguishable between high- and low-density regions, whereas the distribution of ζ parameters have a significant skew towards lower values for galaxies in low-density regions. This result suggests that galaxies in lower density environments are less likely to present weak episodes of recent star formation. In contrast, a significant number of galaxies from our high-density subsample - which includes clusters (both outer regions and centres) and groups - underwent small but detectable recent star formation at high metallicity, in agreement with recent estimates targeting elliptical galaxies in Hickson Compact Groups and in the field.en
dc.format.extent11
dc.language.isoeng
dc.relation.ispartofMonthly Notices of the Royal Astronomical Society
dc.titleDecoding the spectra of SDSS early-type galaxies : New indicators of age and recent star formationen
dc.contributor.institutionSchool of Physics, Astronomy and Mathematics
dc.contributor.institutionScience & Technology Research Institute
dc.contributor.institutionCentre for Astrophysics Research
dc.description.statusPeer reviewed
dc.identifier.urlhttp://www.scopus.com/inward/record.url?scp=36348953351&partnerID=8YFLogxK
rioxxterms.versionSMUR
rioxxterms.versionofrecordhttps://doi.org/10.1111/j.1365-2966.2007.12446.x
rioxxterms.typeJournal Article/Review
herts.preservation.rarelyaccessedtrue


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