SIMBAD references

The Galactic center is the most active site of star formation in the Milky Way, where particularly high-mass stars have formed very recently and are still forming today. However, since we are looking at the Galactic center through the Galactic disk, knowledge of extinction is crucial when studying this region. The Arches cluster is a young, massive starburst cluster near the Galactic center. We observed the Arches cluster out to its tidal radius using K_s-band imaging obtained with NAOS/CONICA at the VLT combined with Subaru/CISCO J-band data to gain a full understanding of the cluster mass distribution. We show that the determination of the mass of the most massive star in the Arches cluster, which had been used in previous studies to establish an upper mass limit for the star formation process in the Milky Way, strongly depends on the assumed slope of the extinction law. Assuming the two regimes of widely used infrared extinction laws, we show that the difference can reach up to 30% for individually derived stellar masses and ΔA_Ks∼1 magnitude in acquired K_s-band extinction, while the present-day mass function slope changes by ∼0.17dex. The present-day mass function slope derived assuming the more recent extinction law increases from a flat slope of α_Nishi=-1.50±0.35 in the core (r<0.2pc) to α_Nishi=-2.21±0.27 in the intermediate annulus (0.2<r<0.4pc), where the Salpeter slope is -2.3. The mass function steepens to α_Nishi=-3.21 ±0.30 in the outer annulus (0.4<r<1.5pc), indicating that the outer cluster region is depleted of high-mass stars. This picture is consistent with mass segregation owing to the dynamical evolution of the cluster.