The BSS and binary content of NGC 5024 (M53): a combined LBT/HST study.
Pasian, F.; Fontana, A.; Grazian, A.; Giallongo, E.; Pulone, L.; Gentile, G.; Ragazzoni, R.; Testa, V.; Beccari, G.; Di Paola, A.; Thompson, D.; Baruffolo, A.; Ferraro, F. R.; Fusi Pecci, F.; Wagner, R. M.; Menci, N.; Lanzoni, B.; Farinato, J.; Rood, R. T.; De Santis, C.; Gallozzi, S.; Speziali, R.; Green, R.; Diolaiti, E.; Smareglia, R.; Pedichini, F.; Gasparo, F.; Hill, J.; Kuhn, O.; Vernet, E.
Italy, United States
Abstract
We present deep, wide-field imaging of the Globular Cluster NGC 5024, obtained at the Large Binocular Telescope. Images in U, B and V were obtained with the Large Binocular Camera, allowing to resolve the stars down to U ∼25.5 in a field of view of 25' × 24' . The combination of short and deep exposures allowed the construction of color-magnitude diagrams spanning all the canonical sequences from the tip of the red giant brunch down to 4 magnitudes below the main sequence Turn Off. Combining this data with high resolution ACS@HST archive images of the central region of the cluster we selected a well defined population of blue stragglers stars, confirming that they have a bimodal radial distribution. Moreover we determined the binary frequency in the outer regions (r>200 arcsec ) of the cluster, finding that about 14% of the stars in these regions are in binary systems.