A Near-Infrared (JHK) Survey of the Vicinity of the HiiRegion NGC 7538: Evidence for a Young Embedded Cluster

We describe the results of two near infrared (K-band) imaging surveys and athree color (JHK) survey of the vicinity of NGC 7538. The limiting magnitudesare K ~ 16.5 and K ~ 17.5 mag for the K-band surveys and K ~ 15 mag for the JHKsurvey. We identify more than 2000 and 9000 near-infrared (NIR) sources on theimages of the two K-band surveys and 786 NIR sources in the JHK survey. Fromcolor-color diagrams, we derive a reddening law for background stars andidentify 238 stars with NIR excesses. Contour maps indicate a high density peakcoincident with a concentration of stars with NIR excesses. We identify thispeak as a young, embedded cluster and confirm this result with the K-bandluminosity function, color histograms, and color-magnitude diagrams. The centerof the cluster is at RA = 23:13:39.34, DEC = 61:29:18.9. The cluster radius is$\sim$ 3' ~ 2.5 pc for an adopted distance, d ~ 2.8 kpc. For d = 2.8 kpc, andreddening, E_{J-K} = 0.55 mag, the slope of the logarithmic K-band luminosityfunction (KLF) of the cluster, s ~ 0.32 +- 0.03, agrees well with previousresults for L1630 (s = 0.34) and M17 (s = 0.26).Comment: 26 pages with 11 figures. Accepted by Astronomical Journa