Inside-out formation of nuclear discs and the absence of old central spheroids in barred galaxies of the TIMER survey

Autor(es):Mostrar menos -

Bittner, Adrian ^{[1, 2]} ; Sanchez-Blazquez, Patricia ^{[3, 4]} ; Gadotti, Dimitri A. ^[1] ; Neumann, Justus ^[5] ; Fragkoudi, Francesca ^[6] ; Coelho, Paula ^[7] ; de Lorenzo-Caceres, Adriana ^{[8, 9]} ; Falcon-Barroso, Jesus ^{[8, 9]} ; Kim, Taehyun ^[10] ; Leaman, Ryan ^[11] ; Martin-Navarro, Ignacio ^{[8, 9]} ; Mendez-Abreu, Jairo ^{[8, 9]} ; Perez, Isabel ^{[12, 13]} ; Querejeta, Miguel ^[14] ; Seidel, Marja K. ^[15] ; van de Ven, Glenn ^[16]

Afiliação do(s) autor(es):Mostrar menos -

^[1] European Southern Observ, Karl Schwarzschild Str 2, D-85748 Garching - Germany

^[2] Ludwig Maximilians Univ Munchen, Prof Huber Pl 2, D-80539 Munich - Germany

^[3] Univ Complutense Madrid, Dept Fis Tierra & Astrofis, Madrid 28040 - Spain

^[4] Univ Complutense Madrid, Inst Fis Particulas & Cosmos, Madrid 28040 - Spain

^[5] Univ Portsmouth, Inst Cosmol & Gravitat, Burnaby Rd, Portsmouth PO1 3FX, Hants - England

^[6] Max Planck Inst Astrophys, Karl Schwarzschild Str 1, D-85748 Garching - Germany

^[7] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, R Matao 1226, BR-05508090 Sao Paulo - Brazil

^[8] Inst Astrofis Canarias, Calle Via Lactea S-N, Tenerife 38205 - Spain

^[9] Univ La Laguna, Dept Astrofis, Tenerife 38200 - Spain

^[10] Kyungpook Natl Univ, Dept Astron & Atmospher Sci, Daegu 702701 - South Korea

^[11] Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg - Germany

^[12] Univ Granada, Fac Ciencias, Dept Fis Teor & Cosmos, Granada 18071 - Spain

^[13] Univ Granada, Inst Univ Carlos I Fis Teor & Computac, Granada 18071 - Spain

^[14] Observ Astron Nacl, C Alfonso XII 3, Madrid 28014 - Spain

^[15] CALTECH, IPAC, MC 314-6, 1200 E Calif Blvd, Pasadena, CA 91125 - USA

^[16] Univ Vienna, Dept Astrophys, Turkenschanzstr 17, A-1180 Vienna - Austria

• Tipo de documento: Artigo Científico
• Fonte: Astronomy & Astrophysics; v. 643, NOV 3 2020.
• Citações Web of Science: 1

Resumo

The centres of disc galaxies host a variety of structures built via both internal and external processes. In this study, we constrain the formation and evolution of these central structures, in particular, nuclear rings and nuclear discs, by deriving maps of mean stellar ages, metallicities, and {[}alpha /Fe] abundances. We use observations obtained with the MUSE integral-field spectrograph for the TIMER sample of 21 massive barred galaxies. Our results indicate that nuclear discs and nuclear rings are part of the same physical component, with nuclear rings constituting the outer edge of nuclear discs. All nuclear discs in the sample are clearly distinguished based on their stellar population properties. As expected in the picture of bar-driven secular evolution, nuclear discs are younger, more metal-rich, and exhibit lower {[}alpha /Fe] enhancements, as compared to their immediate surroundings. Moreover, nuclear discs exhibit well-defined radial gradients, with ages and metallicities decreasing, and {[}alpha /Fe] abundances increasing with radius out to the nuclear ring. Often, these gradients show no breaks from the edge of the nuclear disc up through the centre, suggesting that these structures extend to the very centres of galaxies. We argue that continuous (stellar) nuclear discs may form from a series of bar-built (initially gas-rich) nuclear rings that expand in their radius as the bar evolves. In this picture, nuclear rings are simply the (often) star-forming outer edge of nuclear discs. Finally, by combining our results with those taken from a accompanying kinematic study, we do not find evidence for the presence of large, dispersion-dominated components in the centres of these galaxies. This could be a result of quiet merger histories, despite the large galaxy masses, or, perhaps, due to high angular momentum and strong feedback processes preventing the formation of these kinematically hot components. (AU)

• Processo FAPESP: 18/05392-8 - Uma nova biblioteca de modelos de população estelar puramente teóricos
• Beneficiário: Paula Rodrigues Teixeira Coelho
• Modalidade de apoio: Auxílio à Pesquisa - Regular