Speaker
Description
Accurate distance measurements are crucial for understanding galaxies' stellar populations and dynamics. We present the globular cluster velocity dispersion (GCVD) method, a novel approach for measuring distances to galaxies. This method leverages the established relation between the absolute magnitudes and velocity dispersions of globular clusters (GCs). After testing the technique on 94 Milky Way GCs with known distances, we find that the GCVD method provides results in excellent agreement with independent distance measurements.
Building on this, we apply the GCVD method to NGC 1052-DF2, a galaxy that has attracted attention due to its unusually low dark matter content. Using high-resolution spectroscopic data from the FLAMES GIRAFFE on the VLT, we measure the internal stellar velocity dispersions of 10 globular clusters in this galaxy. Our analysis reveals a distance of 16.2 Mpc for NGC 1052-DF2, which contrasts with the 21.7 Mpc distance derived from the tip of the red giant branch method. This discrepancy highlights the critical importance of precise distance measurements in studying galaxies with unusual properties, such as NGC 1052-DF2.
In addition to distance measurements, we revisit the globular clusters in NGC 1052-DF2, examining their stellar population properties. Our analysis of the GCs suggests that they resemble typical Milky Way GCs in terms of age and metallicity but with a notably low mass-to-light ratio. This suggests that the low dark matter content of NGC 1052-DF2 may affect the formation and evolution of its GCs.
