J/A+A/530/A58ivo://CDS.VizieR/J/A+A/530/A58doi:10.26093/cds/vizier.35300058CDSCrnojevic D.RejkubaM.GrebelE.K.da CostaG.JerjenH.2011-07-16T09:29:37Z2011-05-17T09:47:25ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frgalaxiesphotometrystellar-populationsinfrared-photometryWe investigate the resolved stellar content of early-type dwarf galaxies in the Centaurus A group, to estimate their intermediate-age population fractions. We use near-infrared photometric data taken with the VLT/ISAAC instrument, together with previously analyzed archival HST/ACS data. The combination of the optical and infrared wavelength range permits us to firmly identify luminous asymptotic giant branch stars, which are indicative of an intermediate-age population in these galaxies. We consider one dwarf spheroidal (CenA-dE1) and two dwarf elliptical (SGC1319.1-4216 and ESO269-066) galaxies that are dominated by an old population. The most recent periods of star formation are estimated to have taken place between 2 and 5Gyr ago for SGC1319.1-4216 and ESO269-066, and approximately 9Gyr ago for CenA-dE1. For ESO269-066, we find that the intermediate-age populations are significantly more centrally concentrated than the predominantly old underlying stars. The intermediate-age population fraction is found to be small in the target galaxies, consistent with fractions of up to 15% of the total population. These values might be larger by a factor of two or three, if we considered the observational limitations and the recent discussion about the uncertainties in theoretical models. We suggest that there is a correlation between intermediate-age population fraction and proximity to the dominant group galaxy, with closer dwarfs having slightly smaller fractions, although our sample is too small to draw firm conclusions. Even when considering our results as lower limits, the intermediate-age population fractions for the studied dwarfs are clearly much smaller than those found in similar dwarfs around the Milky Way, but comparable to what is seen for the low-mass M31 companions. Our results confirm our previous work about early-type dwarfs in the Centaurus A group.2011A&A...530A..58Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/530/A58CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/530/A58https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/530/A58http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/530/A58https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/530/A58https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/530/A58http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/530/A58GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/530/A58/table3 (AGB candidates list)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/530/A58/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/530/A58/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/530/A58/table3?GETtext/xml+votable180.050000true198.19195-41.848119440.0055555555555555566/43258 43604 436107.952274030004205e-20 2.6706780932288093e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/530/A58?format=asciiOpticalInfrareddefaultJ/A+A/530/A58/table3AGB candidates listrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGalGalaxy namemeta.id.parentcharIDAGB candidate IDmeta.id;meta.mainintn_ID[*] * indicates variablemeta.notecharRAJ2000Right Ascension J2000pos.eq.ra;meta.mainDEJ2000Declination J2000pos.eq.dec;meta.mainJ0magDereddened apparent J magnitude (1)magphot.mag;em.IR.Jfloate_J0magJ magnitude errormagstat.error;phot.mag;em.IR.JfloatK0magDereddened apparent K magnitude (1)magphot.mag;em.IR.Kfloate_K0magK magnitude errormagstat.error;phot.mag;em.IR.KfloatV0magDereddened apparent V magnitude (1)magphot.mag.reddFree;em.opt.Vfloate_V0magV magnitude errormagstat.error;phot.mag;em.opt.VfloatI0magDereddened apparent I magnitude (1)magphot.mag;em.opt.Ifloate_I0magI magnitude errormagstat.error;phot.mag;em.opt.Ifloat