Multi-conjugate adaptive optics VLT imaging of the distant old open cluster FSR 1415

• Autor(a) principal: Momany, Yazan
• Data de Publicação: 2008
• Outros Autores: Ortolani, Sergio, Bonatto, Charles Jose, Bica, Eduardo Luiz Damiani, Barbuy, Beatriz
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRGS
• Texto Completo: http://hdl.handle.net/10183/90275
• topic: Aglomerados abertos e associações; Populacoes estelares; Aglomerado aberto FSR 1415; Instrumentacao astronomica; Fotometria astronômica; Estrelas; Instrumentation: adaptive optics; Techniques: photometric; Stars: Population II; Open clusters and associations: individual: FSR 1415; Infrared: stars

We employ the recently installed near-infrared Multi-Conjugate Adaptive Optics demonstrator (MAD) to determine the basic properties of a newly identified, old and distant, Galactic open cluster (FSR 1415). The MAD facility remarkably approaches the diffraction limit, reaching a resolution of 0.07 arcsec (in K), that is also uniform in a field of ~ 1.8 arcmin in diameter. The MAD facility provides photometry that is 50 per cent complete at K ~ 19. This corresponds to about 2.5 mag below the cluster main-sequence turn-off. This high-quality data set allows us to derive an accurate heliocentric distance of 8.6 kpc, a metallicity close to solar and an age of ~ 2.5 Gyr. On the other hand, the deepness of the data allows us to reconstruct (completeness-corrected) mass functions (MFs) indicating a relatively massive cluster, with a flat core MF. The Very Large Telescope/MAD capabilities will therefore provide fundamental data for identifying/analysing other faint and distant open clusters in the Galaxy III and IV quadrants.