Near-Infrared Observations of RR Lyrae Variables in $\omega$ Centauri
  We present Near-Infrared (NIR) $J$ and $K_s$-band observations for 181 RR Lyrae stars in the Galactic Globular Cluster $\omega$ Cen. The comparison between predicted and empirical slopes of NIR Period-Luminosity (PL) relations indicates a very good agreement. Cluster distance estimates based on NIR PL relations agree quite well with recent determinations based on different standard candles, giving a true mean distance modulus $\mu = 13.71\pm0.05$, and $d=5.52\pm0.13$ kpc. 
M. Del Principe, A.M. Piersimoni, J. Storm, G. Bono, F. Caputo, S.   Cassisi, L.M. Freyhammer, M. Marconi and P.B. Stetson