INVESTIGADORES
FEINSTEIN BAIGORRI Carlos
artículos
Título:
Massive open star clusters using the VVV survey. I. Presentation of the data and description of the approach
Autor/es:
CHENÉ, A.N.; OTROS; C. FEINSTEIN; ET AL.
Revista:
ASTRONOMY AND ASTROPHYSICS
Editorial:
EDP SCIENCES S A
Referencias:
Lugar: Paris; Año: 2012 vol. 545 p. 1 - 18
ISSN:
0004-6361
Resumen:
Context. The ESO Public Survey "VISTA Variables in the Vía
Láctea" (VVV) provides deep multi-epoch infrared observations for
unprecedented 562 sq. degrees of the Galactic bulge, and adjacent
regions of the disk. Aims: The VVV observations will foster the
construction of a sample of Galactic star clusters with reliable and
homogeneously derived physical parameters (e.g., age, distance, and
mass, etc.). In this first paper in a series, the methodology employed
to establish cluster parameters for the envisioned database are
elaborated upon by analysing four known young open clusters: Danks 1,
Danks 2, RCW 79, and DBS 132. The analysis offers a first glimpse of the
information that can be gleaned from the VVV observations for clusters
in the final database. Methods: Wide-field, deep JHKs
VVV observations, combined with new infrared spectroscopy, are employed
to constrain fundamental parameters for a subset of clusters.
Results: Results are inferred from VVV near-infrared photometry and
numerous low resolution spectra (typically more than 10 per cluster).
The high quality of the spectra and the deep wide-field VVV photometry
enables us to precisely and independently determine the characteristics
of the clusters studied, which we compare to previous determinations. An
anomalous reddening law in the direction of the Danks clusters is found,
specifically E(J - H)/E(H - Ks) = 2.20 ± 0.06, which exceeds
published values for the inner Galaxy. The G305 star forming complex,
which includes the Danks clusters, lies beyond the Sagittarius-Carina
spiral arm and occupies the Centaurus arm. Finally, the first deep
infrared colour-magnitude diagram of RCW 79 is presented, which reveals
a sizeable pre-main sequence population. A list of candidate variable
stars in G305 region is reported. Conclusions: This study
demonstrates the strength of the dataset and methodology employed, and
constitutes the first step of a broader study which shall include
reliable parameters for a sizeable number of poorly characterised and/or
newly discovered clusters.