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dc.contributor.authorBonatto, Charles Josept_BR
dc.contributor.authorBica, Eduardo Luiz Damianipt_BR
dc.contributor.authorPastoriza, Miriani Griseldapt_BR
dc.contributor.authorAlloin, Danielle Mariept_BR
dc.date.accessioned2014-07-18T02:04:41Zpt_BR
dc.date.issued2000pt_BR
dc.identifier.issn0004-6361pt_BR
dc.identifier.urihttp://hdl.handle.net/10183/98102pt_BR
dc.description.abstractThis paper discusses the stellar population content of distant (5 000kms−1 VR 16 000kms−1) galaxies with enhanced star-formation activity. Distinction is made between isolated galaxies and galaxies morphologically disturbed, with clear signs of interaction such as mergers. In these galaxies the International Ultraviolet Explorer (IUE) large aperture samples most of the galaxy’s body. Consequently, the resulting integrated spectra arise primarily from blue stellar populations of different ages together with significant contributions from intermediate and old age components, subject to varying reddening amounts. Instead of analysing individual, usually lowSignal-to- Noise ratio (S/N) spectra, our approach is to coadd the spectra of objects with similar spectral properties in the UV, considering as well their properties in the visible/near-infrared ranges. Consequently, the resulting high (S/N) template spectra contain the average properties of a rather uniform class of objects, and information on spectral features can now be analysed with more precision. Three groups have been found for the interacting galaxies, corresponding to a red, blue and very blue continuum. Isolated galaxies have been separated into two groups, one with a flat/red continuum and the other with a blue continuum. For comparison, we also include in the present analysis two groups of nearby disturbed galaxies. Stellar populations are analysed by means of a synthesis algorithm based on star cluster spectral components of different ages which fit the observed spectra both in terms of continuum distribution and spectral features. Flux fractions of the different age groups found in the synthesis have been transformed into mass fractions, allowing inferences on the star formation histories. Young stellar populations (age < 500 Myr) are the main flux contributors, except for the groups with a red spectrum not due to extinction, arising from the intermediate (age 1−2 Gyr) and old age populations.We also study the reddening values and the extinction law: a Small Magellanic Cloud-like extinction law is appropriate for all cases. As compared to nearby galaxies with enhanced star-formation, the distant starburst galaxy spectral groups exhibit larger contributions from the intermediate and old age populations. This effect is mainly accounted for by the larger spatial area sampled by the IUE slit in the distant galaxies, including not only the entire bulge but also evolved disk populations. The present results provide a quantitative measure of the star-forming activity in interacting galaxies, compared to isolated galaxies.en
dc.format.mimetypeapplication/pdf
dc.language.isoengpt_BR
dc.relation.ispartofAstronomy and astrophysics. New York. Vol. 355, no. 1 (Mar. 2000), p. 99-112pt_BR
dc.rightsOpen Accessen
dc.subjectGalaxies: generalen
dc.subjectGaláxiaspt_BR
dc.subjectGalaxies: interactionsen
dc.subjectGaláxiaspt_BR
dc.subjectGaláxiaspt_BR
dc.subjectGalaxies: starbursten
dc.subjectCores IRASpt_BR
dc.subjectGalaxies: stellar contenten
dc.subjectEmissão em Centaurus Apt_BR
dc.subjectUltraviolet: galaxiesen
dc.subjectNucleo galaticopt_BR
dc.subjectExtinção interestelarpt_BR
dc.subjectSíntese de populaçõespt_BR
dc.subjectPopulacoes estelarespt_BR
dc.subjectGalaxias elipticaspt_BR
dc.subjectNuvens de magalhaespt_BR
dc.titleStar formation in distant starburst galaxiespt_BR
dc.typeArtigo de periódicopt_BR
dc.identifier.nrb000274816pt_BR
dc.type.originEstrangeiropt_BR


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