| Abstract
| - Using the NIRSPEC spectrograph at Keck II, we have obtained infrared echelle spectra covering the 1.5-1.8 μm range for giant stars in the massive bulge globular clusters NGC 6440 and NGC 6441. We report the first high-dispersion abundance for NGC 6440, [Fe/H]=−0.56 ± 0.02 and we find [Fe/H]=−0.50 ± 0.02 for the blue Horizontal Branch cluster NGC 6441. We measure an average α-enhancement of ≈+0.3 dex in both clusters, consistent with previous measurements of other metal rich bulge clusters, and favouring the scenario of a rapid-bulge formation and chemical enrichment. We also measure very low 12C/13C isotopic ratios (≈5 ± 1), suggesting that extra-mixing mechanisms are at work during evolution along the Red Giant Branch also in the high-metallicity regime. We also measure Al abundances, finding average [Al/Fe]= 0.45 ± 0.02 and [Al/Fe]= 0.52 ± 0.02 in NGC 6440 and 6441, respectively, and some Mg-Al anticorrelation in NGC 6441. We also measure radial velocities vr=−76 ± 3 and vr=+14 ± 3 km s−1 and velocity dispersions σ= 9 ± 2 and σ= 10 ± 2 km s−1 in NGC 6440 and 6441, respectively.
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