SIMBAD references

2013AJ....145...46L - Astron. J., 145, 46 (2013/February-0)

The starburst cluster Westerlund 1: the initial mass function and mass segregation.

LIM B., CHUN M.-Y., SUNG H., PARK B.-G., LEE J.-J., SOHN S.T., HUR H. and BESSELL M.S.

Abstract (from CDS):

Westerlund 1 is the most important starburst cluster in the Galaxy due to its massive star content. We have performed BVIC and JKSphotometry to investigate the initial mass function (IMF). By comparing the observed color with the spectral-type-intrinsic-color relation, we obtain the mean interstellar reddening of < E(B - V) > = 4.19±0.23 and < E(J - KS ) > = 1.70±0.21. Due to the heavy extinction toward the cluster, the zero-age main sequence fitting method based on optical photometry proved to be inappropriate for the distance determination, while the near-infrared photometry gave a reliable distance to the cluster–3.8 kpc from the empirical relation. Using the recent theoretical stellar evolution models with rotation, the age of the cluster is estimated to be 5.0±1.0 Myr. We derived the IMF in the massive part and obtained a fairly shallow slope of Γ = -0.8 ±0.1. The integration of the IMF gave a total mass for the cluster in excess of 5.0x104 M. The IMF shows a clear radial variation indicating the presence of mass segregation. We also discuss the possible star formation history of Westerlund 1 from the presence of red supergiants and relatively low luminosity yellow hypergiants.

Abstract Copyright:

Journal keyword(s): open clusters and associations: individual: Westerlund 1 - stars: luminosity function, mass function

VizieR on-line data: <Available at CDS (J/AJ/145/46): table4.dat>

Nomenclature: Table 4: [LCS2013] NNNNN (Nos 1-27521).

Status in Simbad:  could be processed

CDS comments: the radio source A2 is not in Simbad. WR stars B, N, T, X and S = "Cl* Westerlund 1 CN A" in Simbad.

Simbad objects: 51

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2019.12.08-09:59:07

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