• DOI:10.1088/0067-0049/210/1/6
• Corpus ID: 119280050

TOWARD A BETTER UNDERSTANDING OF THE DISTANCE SCALE FROM RR LYRAE VARIABLE STARS: A CASE STUDY FOR THE INNER HALO GLOBULAR CLUSTER NGC 6723

@article{Lee2013TOWARDAB,
  title={TOWARD A BETTER UNDERSTANDING OF THE DISTANCE SCALE FROM RR LYRAE VARIABLE STARS: A CASE STUDY FOR THE INNER HALO GLOBULAR CLUSTER NGC 6723},
  author={Jae-Woo Lee and Mercedes L{\'o}pez-Morales and Kyeongsoo Hong and Young Woon Kang and Brian L. Pohl and Alistair Walker},
  journal={The Astrophysical Journal Supplement Series},
  year={2013},
  volume={210}
}

• Jae-Woo Lee, M. López-Morales, +3 authors A. Walker
• Published 8 November 2013
• Physics
• The Astrophysical Journal Supplement Series

We present BV photometry for 54 variables in the metal-rich inner halo globular cluster NGC 6723. With the discovery of new RR Lyrae variables (RRLs), we obtain 〈Pab〉 = 0.541 ± 0.066 and 〈Pc〉 = 0.292 ± 0.030 day, n(c)/n(ab+c) = 0.167, and 〈V(RR)〉int = 15.459 ± 0.055. We carry out the Fourier decomposition analysis and obtain [Fe/H]ZW = −1.23 ± 0.11 and E(B − V) = 0.063 ± 0.015 for NGC 6723. By calibrating the zero point from the recent absolute trigonometric parallax measurements for RR Lyr, we derive the revised MV(RR)-[Fe/H] relation, providing MV(RR) = 0.52 at [Fe/H] = −1.50 and (m − M)0 = 18.54 for the Large Magellanic Cloud, in excellent agreement with others. We obtain (m − M)0 = 14.65 ± 0.05, equivalent to a distance from the Sun of 8.47 ± 0.17 kpc, for NGC 6723 from various distance measurement methods using RRLs. We find that RRLs in NGC 6723 do not have magnitude dependency on the radial distance because there is not a severe degree of apparent crowdedness. Finally, we show that a relation exists between the degree of photometric contamination and the apparent crowdedness of the central region of globular cluster systems, . The use of this relation can play a significant role in mitigating the discrepancy in establishing a cosmic distance scale using RRLs in resolved stellar populations in near-field cosmology.