Analysis of the WN star WR 102c, its WR nebula, and the associated
  cluster of massive stars in the Sickle Nebula
  The massive Wolf-Rayet type star WR 102c is located near the Quintuplet
Cluster - one of the three massive star clusters in the Galactic Center region.
Previous studies indicated that WR 102c may have a dusty circumstellar nebula
and is among the main ionizing sources of the Sickle Nebula associated with the
Quintuplet cluster. We obtained observations with the ESO's VLT integral field
spectrograph SINFONI in the K-band, extracted the stellar spectra, and analyzed
them by means of stellar atmosphere models. Our new analysis supersedes the
results reported for WR 102c previously. We significantly revise down its
bolometric luminosity and hydrogen content. We detect four early OB type stars
close to WR 102c. These stars have radial velocities similar to that of WR
102c. We suggest that together with WR 102c these stars belong to a distinct
star cluster with a total mass of about 1000 M_sun. We identify a new WR nebula
around WR 102c in the SINFONI map of the diffuse Br$\gamma$ emission and in the
HST's Pa$\alpha$ images. The Br$\gamma$ line at different locations is not
significantly broadened and similar to the width of nebular emission elsewhere
in the H II region around WR 102c. The massive star WR 102c located in the
Galactic Center region resides in a star cluster containing further early type
stars. The stellar parameters of WR 102c are typical for hydrogen-free WN6
stars. We newly identify a nebula surrounding WR 102c that has a morphology
similar to other nebulae around hydrogen-free WR stars, and propose that the
formation of this nebula is linked to interaction of the fast stellar wind with
the matter ejected at previous evolutionary stage of WR 102c.
