Further probing the nature of FSR 1767

Autor(es)

Bonatto, C. ^[1] ; Bica, E. ^[1] ; Ortolani, S. ^[2] ; Barbuy, B. ^[3]

Afiliação do(s) autor(es)

^[1] Univ Fed Rio Grande do Sul, Dept Astron, BR-91501970 Porto Alegre, RS - Brazil

^[2] Univ Padua, Dipartimento Astron, I-35122 Padua - Italy

^[3] Univ Sao Paulo, Dept Astron, BR-05508900 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Monthly Notices of the Royal Astronomical Society; v. 397, n. 2, p. 1032-1040, Aug. 2009.
• Área do conhecimento: Ciências Exatas e da Terra - Astronomia
• Citações Web of Science: 5
• Assunto(s): Meio interestelar Aglomerados de galáxias

Resumo

With Two-Micron All-Sky Survey (2MASS) photometry and proper motions, Bonatto et al. suggested that FSR 1767 is a globular cluster (GC), while with J and K NTT/SOFI photometry Froebrich, Meusinger & Scholz concluded that it is not a star cluster. In this study, we combine previous and new evidence that are consistent with a GC. For instance, we show that the horizontal branch (HB) and red giant branch (RGB) stars, besides sharing a common proper motion, have radial density profiles that consistently follow the King's law independently. Reddening maps around FSR 1767 are built using the bulge RGB as reference and also Schlegel's extinction values to study local absorptions. Both approaches provide similar maps and show that FSR 1767 is not located in a dust window, which otherwise might have produced the stellar overdensity. Besides, neighbouring regions of similar reddening as FSR 1767 do not present the blue HB stars that are a conspicuous feature in the colour-magnitude diagram of FSR 1767. We report the presence of a compact group of stars located in the central parts of FSR 1767. It appears to be a detached post-collapse core, similar to those of other nearby low-luminosity GCs projected towards the bulge. We note that while the NTT/SOFI photometry of the star cluster FSR 1716 matches perfectly that from 2MASS, it shows a considerable offset for FSR 1767. We discuss the possible reasons why both photometries differ. We confirm our previous structural and photometric fundamental parameters for FSR 1767, which are consistent with a GC. (AU)

• Processo FAPESP: 06/50367-4 - Galáxias: populações estelares, evolução e condições ambientais
• Beneficiário: Beatriz Leonor Silveira Barbuy
• Modalidade de apoio: Auxílio à Pesquisa - Regular