Panchromatic fits to the Globular Cluster NGC 6366

TL;DR

This study performs comprehensive panchromatic isochrone fitting to the globular cluster NGC 6366 using HST and SOAR data, comparing stellar evolution models to determine its properties.

Contribution

It introduces a detailed methodology for fitting isochrones across multiple wavelengths and evaluates different stellar evolution models against observational data.

Findings

Dartmouth models fit the sub giant and low main sequence better.

Estimated metallicity is [Fe/H] = -0.67 with E(B-V)=0.69.

Cluster age is approximately 11 Gyr.

Abstract

We present panchromatic isochrone fits to the color magnitude data of the globular cluster NGC 6366, based on HST ACS/WFC and SOAR photometric data. Before performing the isochrone fits, we corrected the photometric data for differential reddening and calculated the mean ridge line of the color magnitude diagrams. We compared the isochrones of Dartmouth Stellar Evolution Database and PAdova and TRieste Stellar Evolution Code (with microscopic diffusion starting on the main sequence). Based on previous determinations of the metallicity of this cluster we test it from [Fe/H]=-1.00 to [Fe/H]= -0.50, and the age from 9 to 13 Gyrs. The uncertainties do not decrease when we fit simultaneous colors. We also find that the Dartmouth Stellar Evolution Database isochrones have a better fit in the sub giant branch and low main sequence than the PAdova and TRieste Stellar Evolution Code. Considering the most recent spectroscopic determination of the metallicity ([Fe/H]= -0.67), we find E(B-V)=0.69+/-0.02, (m-M)_V=15.02+/-0.07 and 11+/-2 Gyr for NGC 6366.