Using photometric data from the 2MASS second incremental release point source catalog we constructed K _ { s } vs. ( J - K _ { s } ) color-magnitude diagrams ( CMDs ) of Galactic globular clusters ( GGCs ) for which the JK _ { s } photometric data have been made available up to now .
On the CMDs of 13 GGCs we identified RGB bump features and derived luminosities of bumps in K _ { s } ( K _ { s } ^ { Bump } ) and in M _ { K _ { s } } ( M _ { K _ { s } } ^ { Bump } ) for 11 of them .
We reconfirm the relation between M _ { K _ { s } } ^ { Bump } and metallicity [ Fe/H ] _ { CG 97 } or [ M/H ] such that the luminosity of bump becomes brighter as metallicity [ Fe/H ] _ { CG 97 } or [ M/H ] decreases .
This result is similar to that obtained by Ferraro et al .
( 1999 ) for the relation between M _ { V } ^ { Bump } and [ M/H ] based on observations of 47 GGCs which were conducted in the optical region ( in V vs. ( B - V ) CMDs ) .
Our results show the same trend as those found by Ferraro et al .
( 2000 ) for the relations between M _ { K } ^ { Bump } and metallicity [ Fe/H ] _ { cg 97 } and [ M/H ] derived from observations of 8 GGCs in the same near-infrared region ( K vs. ( J - K ) CMDs ) .
Combining with the data of Ferraro et al .
( 2000 ) , we derive a robust relation for the metal-dependent luminosities of the bumps .