I present the first results of multiple stellar populations in globular clusters from James Webb Space Telescope (JWST) data. We obtained combined NIRSpec and NIRCam data of the GC 47 Tucanae to investigate the properties of the different stellar populations in the low-mass regime, down to ∼0.5 M⊙. Our analysis of both the photometric data and the spectra suggests that the multiple stellar populations among M dwarfs share similar properties of those extensively studied on bright red giant branch stars. The comparison between stellar populations’ properties at different stellar mass, e.g. at the red giants and M dwarfs’ phases, can potentially provide strong constraints to the formation scenarios of the still eluding phenomenon of the multiple populations in star clusters.

I present the first evidence of multiple populations in the globular cluster (GCs) 47 Tucanae based on images collected with the near-infrared camera (NIRCam) on board the James Webb Space Telescope (JWST). While NIRCam photometry is poorly sensitive to multiple populations among stars brighter than the main-sequence (MS) knee, the M-dwarfs more-massive than ∼0.1 define a wide color range due to multiple populations. The star-to-star color differences are mostly due to the different amounts of water vapor (hence oxygen) that affect the spectra of M-dwarfs. The chromosome map unveils an extended first population (1P) composed of M-dwarfs with different metallicities and three main groups of second-population (2P) stars that are depleted in oxygen with respect to the 1P. I present the discovery of an MS of very-low-mass stars and tentatively associated it with a sequence composed of O-rich stars alone.

This paper presents the design and science goals for the SkyMapper telescope. SkyMapper is a 1.3-m telescope featuring a 5.7-square-degree field-of-view Cassegrain imager commissioned for the Australian National University's Research School of Astronomy and Astrophysics. It is located at Siding Spring Observatory, Coonabarabran, NSW, Australia and will see first light in late 2007.

The imager possesses 16 384 × 16 384 0.5-arcsec pixels. The primary scientific goal of the facility is to perform the Southern Sky Survey, a six-colour and multi-epoch (four-hour, one-day, one-week, one-month and one-year sampling) photometric survey of the southerly 2π sr to g ∼23 mag. The survey will provide photometry to better than 3% global accuracy and astrometry to better than 50 milliarcsec. Data will be supplied to the community as part of the Virtual Observatory effort. The survey will take five years to complete.

Setting constraints on the evolutionary history of a galaxy requires informations about the age and metallicity of its stellar content. However, outside the Local Group of galaxies representative surveys on the age and metallicity of stellar populations in galaxies of different types (e.g. luminosity, environment) can only be performed with photometry. The latter requires special care in order to overcome the age- metallicity degeneracy of broad band colors. Combining optical and near-infrared observations of globular clusters is a powerful tool in this respect, using the different sensitivity of broad band colors regarding both parameters. Based on Single Stellar Population (SSP) models we derive the cumulative age distribution for various globular cluster systems and compare it to simulated systems with a known age distribution. So far this method has been tested successfully on various early-type galaxies, revealing a second generation of globular clusters in two galaxies in a sample of eight with convincing reliability.