STAR FORMATION HISTORY OF THE SMALL MAGELLANIC CLOUD: SIX HUBBLE SPACE TELESCOPE/ADVANCED CAMERA FOR SURVEY FIELDS

Journal Article · Sun Sep 20 00:00:00 EDT 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/703/1/721· OSTI ID:21371968

Sabbi, E; Anderson, J; Nota, A ^[1]; Gallagher, J S; Cignoni, M ^[2]; Tosi, M; Harbeck, D ^[3]; Grebel, E K ^[4]; Cole, A A ^[5]; Da Costa, G S ^[6]; Glatt, K ^[7]; Marconi, M ^[8]

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1. STScI, San Martin Drive, Baltimore, MD 21218 (United States)
2. University of Wisconsin, Madison, WI (United States)
3. INAF-Osservatorio Astronomico di Bologna, Bologna (Italy)
4. Astronomisches Rechen-Institut, Zentrum fuer Astronomie der Universitaet Heidelberg, Heidelberg (Germany)
5. School of Mathematics and Physics, Tasmania (Australia)
6. Research School of Astronomy and Astrophysics, The Australian National University, Weston (Australia)
7. European Space Agency, Research and Scientific Support Department, Baltimore, MD (United States)
8. INAF-Osservatorio Astronomico di Capodimonte, Napoli (Italy)

We observed six fields of the Small Magellanic Cloud (SMC) with the Advanced Camera for Survey on board the Hubble Space Telescope in the F555W and F814W filters. These fields sample regions characterized by very different star and gas densities, and, possibly, by different evolutionary histories. We find that the SMC was already forming stars {approx}12 Gyr ago, even if the lack of a clear horizontal branch suggests that in the first few billion years the star formation activity was low. Within the uncertainties of our two-band photometry, we find evidence of a radial variation in chemical enrichment, with the SMC outskirts characterized by lower metallicity than the central zones. From our color-magnitude diagrams, we also infer that the SMC formed stars over a long interval of time until {approx}2-3 Gyr ago. After a period of modest activity, star formation increased again in the recent past, especially in the bar and the wing of the SMC, where we see an enhancement in the star-formation activity starting from {approx}500 Myr ago. The inhomogeneous distribution of stars younger than {approx}100 Myr indicates that recent star formation has mainly developed locally.

• OSTI ID: 21371968
• Journal Information: Astrophysical Journal, Vol. 703, Issue 1; Other Information: DOI: 10.1088/0004-637X/703/1/721; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
CAMERAS
COLOR
GALACTIC EVOLUTION
MAGELLANIC CLOUDS
PHOTOMETRY
STARS
TELESCOPES
EVOLUTION
GALAXIES
OPTICAL PROPERTIES
ORGANOLEPTIC PROPERTIES
PHYSICAL PROPERTIES