A near-infrared (JHK) survey of the vicinity of the HII region NGC 7538:: Evidence for a young embedded cluster

We describe the results of two near-infrared (K-band) imaging surveys and a three-color (JHK) survey of the vicinity of NGC 7538. The limiting magnitudes are Ksimilar or equal to16.5 and 17.5 mag for the K-band surveys and Ksimilar or equal to15 mag for the JHK survey. We identify more than 2000 and 9000 near-infrared (NIR) sources on the images of the two K-band surveys and 786 NIR sources in the JHK survey. From color-color diagrams, we derive a reddening law for background stars and identify 238 stars with NIR excesses. Contour maps indicate a high-density peak coincident with a concentration of stars with NIR excesses. We identify this peak as a young embedded cluster and confirm this result with the K-band luminosity function (KLF), color histograms, and color-magnitude diagrams. The center of the cluster is at R.A.=23(h)13(m)39.(s)34, decl.=61degrees29'18"9. The cluster radius is similar to3', similar to2.5 pc for an adopted distance dsimilar or equal to2.8 kpc. For d=2.8 kpc and reddening EJ-K=0.55 mag, the slope of the logarithmic KLF of the cluster, ssimilar to0.32+/-0.03, agrees well with previous results for L1630 (s=0.34) and M17 (s=0.26) found by C. Lada, E. Lada, and coworkers.