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arXiv · 1511.00744

Spiral-like star-forming patterns in CALIFA early-type galaxies

J. M. Gomes·P. Papaderos·J. M. Vílchez·C. Kehrig·J. Iglesias-Páramo·I. Breda·M. D. Lehnert·S. F. Sánchez·B. Ziegler·S. N. dos Reis·J. Bland-Hawthorn·L. Galbany·D. J. Bomans·F. F. Rosales-Ortega·C. J. Walcher·R. García-Benito·I. Márquez·A. del Olmo·M. Mollá·R. A. Marino·C. Catalán-Torrecilla·R. M. González Delgado·Á. R. López-Sánchez·the CALIFA collaboration
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Abstract

Based on a combined analysis of SDSS imaging and CALIFA integral field spectroscopy data, we report on the detection of faint (24 < μ$_r$ mag/arcsec$^2$ < 26) star-forming spiral-arm-like features in the periphery of three nearby early-type galaxies (ETGs). These features are of considerable interest because they document the still ongoing inside-out growth of some local ETGs and may add valuable observational insight into the origin and evolution of spiral structure in triaxial stellar systems. A characteristic property of the nebular component in the studied ETGs, classified i+, is a two-radial-zone structure, with the inner zone that displays faint (EW(Hα)$\simeq$1Å) low-ionization nuclear emission-line region (LINER) properties, and the outer one (3Å<EW(Hα)<~20Å) HII-region characteristics. This spatial segregation of nebular emission in two physically distinct concentric zones calls for an examination of aperture effects in studies of type i+ ETGs with single-fiber spectroscopic data.

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J. M. Gomes, P. Papaderos, J. M. Vílchez, C. Kehrig, J. Iglesias-Páramo, I. Breda, M. D. Lehnert, S. F. Sánchez, B. Ziegler, S. N. dos Reis, J. Bland-Hawthorn, L. Galbany, D. J. Bomans, F. F. Rosales-Ortega, C. J. Walcher, R. García-Benito, I. Márquez, A. del Olmo, M. Mollá, R. A. Marino, C. Catalán-Torrecilla, R. M. González Delgado, Á. R. López-Sánchez, the CALIFA collaboration. 2015-11-02. Spiral-like star-forming patterns in CALIFA early-type galaxies. https://doi.org/10.1051/0004-6361%2F201525974

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