Open AccessRed giant branch in near‐infrared colour–magnitude diagrams – I. Calibration of photometric indices
Author(s) -
Valenti E.,
Ferraro F. R.,
Origlia L.
Publication year - 2004
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2004.07861.x
Subject(s) - physics , globular cluster , photometry (optics) , astrophysics , metallicity , sky , red giant branch , halo , astronomy , magnitude (astronomy) , infrared , photometric system , milky way , galaxy , bulge , stars
We present new high‐quality near‐infrared photometry of 10 Galactic globular clusters spanning a wide metallicity range (−2.12 ≤[Fe/H]≤− 0.49 ): five clusters belong to the halo (NGC 288, 362, 6752, M15 and M30) and five (NGC 6342, 6380, 6440, 6441 and 6624) to the bulge. By combining J , H and K observations with optical data, we constructed colour–magnitude diagrams in various planes: ( K , J – K ), ( K , V – K ), ( H , J – H ) and ( H , V – H ). A set of photometric indices (colours, magnitudes and slopes) describing the location and the morphology of the red giant branch (RGB) have been measured. We have combined this new data set with those collected by our group over the last 5 years, and here we present an updated calibration of the various RGB indices in the Two‐Micron All‐Sky Survey photometric system, in terms of the cluster metallicity.