Recovering the origins of the lenticular galaxy NGC 3115 using multiband imaging

Author(s):Show less -

Buzzo, Maria Luisa ^[1] ; Cortesi, Arianna ^{[1, 2]} ; Hernandez-Jimenez, Jose A. ^{[1, 3]} ; Coccato, Lodovico ^[4] ; Werle, Ariel ^{[1, 5]} ; Beraldo e Silva, Leandro ^[6] ; Grossi, Marco ^[2] ; Vika, Marina ^[7] ; Barbosa, Carlos Eduardo ^[1] ; Lucatelli, Geferson ^[8] ; Santana-Silva, Luidhy ^[9] ; Bamford, Steven ^[10] ; Debattista, Victor P. ^[6] ; Forbes, Duncan A. ^[11] ; Overzier, Roderik ^{[1, 12]} ; Romanowsky, Aaron J. ^{[13, 14]} ; Ferrari, Fabricio ^[8] ; Brodie, Jean P. ^{[14, 11]} ; de Oliveira, Claudia Mendes ^[1]

Affiliation:Show less -

^[1] Univ Sao Paulo, IAG, Rua Matao 1226, Cidade Univ, BR-05508900 Sao Paulo - Brazil

^[2] Observ Valongo, Ladeira Pedro Antonio 43, BR-20080090 Rio De Janeiro, RJ - Brazil

^[3] Univ Andres Bello, Dept Ciencias Fis, Fernandez Concha 700, Santiago 7591538 - Chile

^[4] European Southern Observ, Karl Schwarzchild Str 2, D-85748 Garching - Germany

^[5] INAF Osservatorio Astron Padova, Vicolo Osservatorio 5, I-35122 Padua - Italy

^[6] Univ Cent Lancashire, Jeremiah Horrocks Inst, Preston PR1 2HE, Lancs - England

^[7] Natl Observ Athens, Inst Astron Astrophys Space Applicat & Remote Sen, Athens 15236 - Greece

^[8] Univ Fed Rio Grande IMEF FURG, Inst Matemat Estat & Fis, Rio Grande, RS - Brazil

^[9] NAT Univ Cruzeiro do Sul, Rua Galvao Bueno 868, BR-01506000 Sao Paulo, SP - Brazil

^[10] Univ Nottingham, Sch Phys & Astron, Univ Pk, Nottingham NG7 2RD - England

^[11] Swinburne Univ, Ctr Astrophys & Supercomp, Hawthorn, Vic 3122 - Australia

^[12] Observatorio Nacl, Rua Jose Cristino 77, BR-20921400 Rio De Janeiro, RJ - Brazil

^[13] Univ Calif Observ, 1156 High St, Santa Cruz, CA 95064 - USA

^[14] San Jose State Univ, Dept Phys & Astron, One Washington Sq, San Jose, CA 95192 - USA

• Document type: Journal article
• Source: Monthly Notices of the Royal Astronomical Society; v. 504, n. 2, p. 2146-2167, JUN 2021.
• Web of Science Citations: 0

Abstract

A detailed study of the morphology of lenticular galaxies is an important way to understand how this type of galaxy is formed and evolves over time. Decomposing a galaxy into its components (disc, bulge, bar, ...) allows recovering the colour gradients present in each system, its star formation history, and its assembly history. We use GALFITM to perform a multiwavelength structural decomposition of the closest lenticular galaxy, NGC 3115, resulting in the description of its stellar light into several main components: a bulge, a thin disc, a thick disc, and also evidence of a bar. We report the finding of central bluer stellar populations in the bulge, as compared to the colour of the galaxy outskirts, indicating either the presence of an active galactic nucleus (AGN) and/or recent star formation activity. From the spectral energy distribution results, we show that the galaxy has a low luminosity AGN component, but even excluding the effect of the nuclear activity, the bulge is still bluer than the outer-regions of the galaxy, revealing a recent episode of star formation. Based on all of the derived properties, we propose a scenario for the formation of NGC 3115 consisting of an initial gas-rich merger, followed by accretions and feedback that quench the galaxy, until a recent encounter with the companion KK084 that reignited the star formation in the bulge, provoked a core displacement in NGC 3115 and generated spiral-like features. This result is consistent with the two-phase formation scenario, proposed in previous studies of this galaxy. (AU)

• FAPESP's process: 19/23388-0 - The formation history of ultra diffuse galaxies
• Grantee: Maria Luísa Gomes Buzzo
• Support Opportunities: Scholarships in Brazil - Doctorate