The Large Magellanic Cloud stellar content with SMASH I. Assessing the stability of the Magellanic spiral arms
Metadatos
Mostrar el registro completo del ítemEditorial
EDP Sciences
Materia
Methods: observational Techniques: photometric Galaxy: stellar content Magellanic Clouds
Fecha
2020-07-09Referencia bibliográfica
Ruiz-Lara, T., Gallart, C., Monelli, M., Nidever, D., Dorta, A., Choi, Y., ... & Massana, P. (2020). The Large Magellanic Cloud stellar content with SMASH-I. Assessing the stability of the Magellanic spiral arms. Astronomy & Astrophysics, 639, L3. [DOI: 10.1051/0004-6361/202038392]
Patrocinador
AEI/FEDER, UE AYA201789076-P AYA2016-77237-C3-1-P AYA2015-63810-P; Ministerio de Ciencia, Innovacion y Universidades (MCIU), through Juan de la Cierva - Formacion grant FJCI-2016-30342; Consejeria de Economia, Industria, Comercio y Conocimiento of the Canary Islands Autonomous Community, through Regional Budget; Spanish Public State Employment Service (SEPE); National Science Foundation (NSF) AST 1655677 AST-1909497; Premiale INAF "MITIC"; Ministry of Economy and Competitiveness of Spain AYA201342781P; INFN (Iniziativa specifica TAsP); European Research Council (ERC) 682115; "Centre of Excellence Severo Ochoa" award SEV-2017-0709; Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) CONICYT FONDECYT 1181797; Max Planck Society through a Partner Group grant; Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) CONICYT PIA/BASAL AFB-170002; Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) CONICYT FONDECYT 1170364; AYA2016-81065-C2-2; PGC2018-095049-B-C21Resumen
The Large Magellanic Cloud (LMC) is the closest and most studied example of an irregular galaxy. Among its principal defining
morphological features, its off-centred bar and single spiral arm stand out, defining a whole family of galaxies known as the Magellanic
spirals (Sm). These structures are thought to be triggered by tidal interactions and possibly maintained via gas accretion. However, it
is still unknown whether they are long-lived stable structures. In this work, by combining photometry that reaches down to the oldest
main sequence turn-off in the colour-magnitude diagrams (CMD, up to a distance of ∼4.4 kpc from the LMC centre) from the SMASH
survey and CMD fitting techniques, we find compelling evidence supporting the long-term stability of the LMC spiral arm, dating
the origin of this structure to more than 2 Gyr ago. The evidence suggests that the close encounter between the LMC and the Small
Magellanic Cloud (SMC) that produced the gaseous Magellanic Stream and its Leading Arm also triggered the formation of the LMC’s
spiral arm. Given the mass difference between the Clouds and the notable consequences of this interaction, we can speculate that this
should have been one of their closest encounters. These results set important constraints on the timing of LMC-SMC collisions, as
well as on the physics behind star formation induced by tidal encounters.