A near-infrared photometric survey of metal-poor inner spheroid globular clusters and nearby bulge fields

Images recorded through J, H, K, 2.2 mu m continuum, and CO filters have be en obtained of a sample of metal-poor ([Fe/H] less than or equal to -1.3) g lobular clusters in the inner spheroid of the Galaxy. The shape and color o f the upper giant branch on the (K, J-K) color-magnitude diagram (CMD), com bined with the K brightness of the giant branch tip, are used to estimate t he metallicity, reddening, and distance of each cluster. CO indices are use d to identify bulge stars, which will bias metallicity and distance estimat es if not culled from the data. The distances and reddenings derived from t hese data are consistent with published values, although there are exceptio ns. The reddening-corrected distance modulus of the Galactic center, based on the Carney et al. horizontal-branch (HB) brightness calibration, is esti mated to be 14.9 +/- 0.1. The mean upper giant branch CO index shows cluste r-to-cluster scatter that (1) is larger than expected from the uncertaintie s in the photometric calibration and (2) is consistent with a dispersion in CNO abundances comparable to that measured among halo stars. The luminosit y functions (LFs) of upper giant branch stars in the program clusters tend to be steeper than those in the halo clusters NGC 288, NGC 362, and NGC 708 9. The majority of inner spheroid clusters fall along the integrated J-K ve rsus metallicity relation defined by halo clusters; however, many of the in ner spheroid clusters do not follow the relation between integrated CO inde x and metallicity measured for halo clusters, in that they have CO indices that are too small. Bulge fields were also observed near most clusters. The slope of the giant branch LF does not vary significantly between most fiel ds, although the LFs in Baade's window and near NGC 6273 are significantly shallower than average. Metallicities estimated from the slope of the upper giant branch on the (K, J-K) CMDs of fields within 6 degrees of the Galact ic center are consistent with previous studies. Finally, the data suggest t hat the HE content may not be uniform throughout the bulge, in the sense th at a larger than average number of red HE stars may occur in fields closest to the Galactic center.