Details

Autor(en) / Beteiligte

• Rubele, Stefano
• Girardi, Léo
• Kerber, Leandro
• Cioni, Maria-Rosa L.
• Piatti, Andrés E.
• Zaggia, Simone
• Bekki, Kenji
• Bressan, Alessandro
• Clementini, Gisella
• de Grijs, Richard
• Emerson, Jim P.
• Groenewegen, Martin A. T.
• Ivanov, Valentin D.
• Marconi, Marcella
• Marigo, Paola
• Moretti, Maria-Ida
• Ripepi, Vincenzo
• Subramanian, Smitha
• Tatton, Benjamin L.
• van Loon, Jacco Th

Titel

The VMC survey – XIV. First results on the look-back time star formation rate tomography of the Small Magellanic Cloud

Ist Teil von

• Monthly notices of the Royal Astronomical Society, 2015-05, Vol.449 (1), p.639-661

Ort / Verlag

London: Oxford University Press

Erscheinungsjahr

2015

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• We analyse deep images from the VISTA survey of the Magellanic Clouds in the $YJ{K_{\rm s}}$ filters, covering 14 deg2 (10 tiles), split into 120 subregions, and comprising the main body and Wing of the Small Magellanic Cloud (SMC). We apply a colour–magnitude diagram reconstruction method that returns their best-fitting star formation rate SFR(t), age–metallicity relation (AMR), distance and mean reddening, together with 68 per cent confidence intervals. The distance data can be approximated by a plane tilted in the East–West direction with a mean inclination of 39°, although deviations of up to ±3 kpc suggest a distorted and warped disc. After assigning to every observed star a probability of belonging to a given age–metallicity interval, we build high-resolution population maps. These dramatically reveal the flocculent nature of the young star-forming regions and the nearly smooth features traced by older stellar generations. They document the formation of the SMC Wing at ages <0.2 Gyr and the peak of star formation in the SMC Bar at ∼40 Myr. We clearly detect periods of enhanced star formation at 1.5 and 5 Gyr. The former is possibly related to a new feature found in the AMR, which suggests ingestion of metal-poor gas at ages slightly larger than 1 Gyr. The latter constitutes a major period of stellar mass formation. We confirm that the SFR(t) was moderately low at even older ages.