Analysis of color-magnitude diagrams from three large Magellanic Cloud clusters

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5612441

Jones, J H

The color-magnitude diagrams of three LMC clusters and a field were derived from photographic and CCD data provided by Dr. P.J. Flower of Clemson University and Dr. R. Schommer of Rutgers University. The photographic data were scanned and converted to intensity images at KPNO. The stellar photometry program RICHFLD was used to measure the raw magnitudes from these images. Problems with the standard sequence on the plate kept the color terms for the photographic data from being well determined. A version of DAOPHOT was installed on the VAX 11/280s at Clemson and was used to measure the magnitudes from the CCD images of NGC 2249. These magnitudes were used to define another photoelectric sequence for the photographic data which were used to determine a well defined transformation into the standard BV system. The CMDs derived from both the photographic and CCD images of NGC 2249 showed a gap near the tip of the MS. This gap was taken to be the period of rapid evolution just after core hydrogen exhaustion. Using a true distance modulus of 18.3 for the LMC and a reddening taken from the literature, an age of 600 +/- 75 million years was found for NGC 2249. Comparing the CMD of SL 889 to that of NGC 2249 gives a similar age for this small LMC cluster. A subgiant branch was identified in the CMD of NGC 2241. Comparison to old metal poor galactic clusters gave an age near 4 billion years, favoring the short distance scale to the LMC.

• Research Organization: Clemson Univ., SC (USA)
• OSTI ID: 5612441
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AGE ESTIMATION
COLOR
GALACTIC EVOLUTION
GALAXIES
GALAXY CLUSTERS
MAGELLANIC CLOUDS
OPTICAL PROPERTIES
ORGANOLEPTIC PROPERTIES
PHOTOGRAPHY
PHYSICAL PROPERTIES