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Authordc.contributor.authorGomes, J.
Authordc.contributor.authorPapaderos, P.
Authordc.contributor.authorVilchez, J.
Authordc.contributor.authorKehrig, C.
Authordc.contributor.authorIglesias Paramo, J.
Authordc.contributor.authorBreda, I.
Authordc.contributor.authorLehnert, M.
Authordc.contributor.authorSánchez, S.
Authordc.contributor.authorZiegler, B.
Authordc.contributor.authordos Reis, S.
Authordc.contributor.authorBland Hawthorn, J.
Authordc.contributor.authorGalbany, Lluis
Authordc.contributor.authorBomans, D.
Authordc.contributor.authorRosales Ortega, F.
Authordc.contributor.authorWalcher, C.
Authordc.contributor.authorGarcia Benito, R.
Authordc.contributor.authorMarquez, I.
Authordc.contributor.authorOlmo, A. del
Authordc.contributor.authorMolla, M.
Authordc.contributor.authorMarino, R.
Authordc.contributor.authorCatalán Torrecilla, C.
Authordc.contributor.authorGonzález Delgado, R.
Authordc.contributor.authorLópez Sánchez, Ángel R.
Admission datedc.date.accessioned2016-06-17T20:57:58Z
Available datedc.date.available2016-06-17T20:57:58Z
Publication datedc.date.issued2016
Cita de ítemdc.identifier.citationAstronomy & Astrophysics Volumen: 586 Número de artículo: A22 (2016)en_US
Identifierdc.identifier.otherDOI: 10.1051/0004-6361/201527312
Identifierdc.identifier.urihttps://repositorio.uchile.cl/handle/2250/139013
General notedc.descriptionArtículo de publicación ISIen_US
Abstractdc.description.abstractIntegral field spectroscopy (IFS) studies based on CALIFA survey data have recently revealed ongoing low-level star formation (SF) in the periphery of a small fraction (similar to 10%) of local early-type galaxies (ETGs), witnessing a still ongoing inside-out galaxy growth process. A distinctive property of the nebular component in these ETGs, classified i +, is a structure with two radial zones, the inner of which displays LINER emission with a H alpha equivalent width EW(H alpha) similar or equal to 1 angstrom, the outer (3 angstrom < EW(H alpha) less than or similar to 20 angstrom) HII-region characteristics. Using CALIFA IFS data, we empirically demonstrate that the confinement of nebular emission to the galaxy periphery leads to a strong aperture (or, correspondingly, redshift) bias in spectroscopic single-fiber studies of type i + ETGs: at low redshift (z less than or similar to 0 : 45), SDSS spectroscopy is restricted to the inner (SF-devoid LINER) zone, which causes the galaxies to be erroneously classified as "retired", that is, systems entirely lacking SF, and whose faint nebular emission is solely powered by the post-AGB stellar component. The SDSS aperture progressively encompasses the outer SF zone only at higher z, at which the galaxies are unambiguously classified as "composite SF/LINER". We also empirically demonstrate that the principal effect of a decreasing spectroscopic aperture on the classification of i + ETGs through standard [NII]/H alpha vs. [OIII]/H beta emission-line (BPT) ratios consists of a monotonic shift upward and to the right precisely along the upper right wing of the "seagull" distribution on the BPT plane, that is, along the pathway connecting composite SF/HII galaxies with AGN /LINERs. Motivated by these observational insights, we also investigate theoretically observational biases in aperture-limited studies of inside-out growing galaxies as a function of z. To this end, we devise a simple 1D model that involves an outward-propagating exponentially decreasing SF process since z similar to 10 and reproduces the radial extent and two-zone EW(H alpha) distribution of local i + ETGs. By simulating the 3 '' spectroscopic SDSS aperture in this model, we find that SDSS studies at z less than or similar to 1 are progressively restricted to the inner (SF-devoid LINER) zone and miss an increasingly larger portion of the H alpha-emitting periphery. This leads to the incorrect spectroscopic classification of these inside-out assembling galaxies as retired ETG /LINERs and also to a severe underestimation of their total star formation rate (SFR) in a manner inversely related to z. More specifically, the SFR inferred from the H ff luminosity registered within the SDSS fiber is reduced by 50% at z similar to 0 : 86, reaching only 0.1% of its integral value at z = 0.1. We argue that the aperture-driven biases described above pertain to any morphological analog of i + ETGs (e.g., SF-quiescent bulges within star-forming disks), regardless of whether it is viewed from the perspective of inside-out growth or inside-out SF quenching, and might be of considerable relevance to galaxy taxonomy and studies of the cosmic SFR density as a function of z.en_US
Patrocinadordc.description.sponsorshipCONICYT through FONDECYT 3140566en_US
Lenguagedc.language.isoenen_US
Publisherdc.publisherEDP SCIENCESen_US
Type of licensedc.rightsAtribución-NoComercial-SinDerivadas 3.0 Chile*
Link to Licensedc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/3.0/cl/*
Keywordsdc.subjectgalaxies: elliptical and lenticular, cDen_US
Keywordsdc.subjectgalaxies: nucleien_US
Keywordsdc.subjectgalaxies: ISMen_US
Keywordsdc.subjectgalaxies: star formationen_US
Títulodc.titleSpectroscopic aperture biases in inside-out evolving early-type galaxies from CALIFAen_US
Document typedc.typeArtículo de revista


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Atribución-NoComercial-SinDerivadas 3.0 Chile
Except where otherwise noted, this item's license is described as Atribución-NoComercial-SinDerivadas 3.0 Chile