JHK imaging photometry of Tr 14, Tr 15 and Tr 16

Abstract

We have observed the areas associated with the young open clusters Tr 14, Tr 15 and Tr 16 of the Eta Carinae Region in the near-infrared (J, H and K'), using a NICMOS 3 array detector (256 x 256 pixels) and the Swope lm telescope of Las Campanas Observatory. The images are sampled to 0.45 arcsec per pixel under an average seeing of 1.5 arcsec. Calibration of these images was performed using the magnitudes obtained for individual stars with existing single-detector photometry. The limiting magnitudes are, approximately, 15 in J and H, and 14.5 in the K' filter, thus greatly extending the available data base. These data will be used with our UBVRI CCD photometry (Tapia et al., this meeting) to determine in greater detail the interstellar and intra-cluster extinction laws and to derive individual reddening. This will allow us to obtain accurate distances, bolometric magnitudes, photometric spectral types, HR diagrams and the Initial Mass Function of each cluster. A number of very red sources have been detected and their nature will be discussed.