Photometric Calibration

Absolute photometry has been obtained by observing several standard stars taken from the list of Infrared NICMOS Standard Stars kindly provided by E. Persson. The stars have magnitudes in the range10.8<Ks<11.7 and 11.3<J<12.0 and instrumental total magnitudes have been estimated by deriving the growth curve for each star. The estimated magnitudes have been corrected for extinction using AKs=0.11 and AJ=0.08 and the derived zero points, reported inTab.1, have an uncertainty of 0.02 mag.

Note that both the J and Ks FITS files are normalized to 1 sec.