We used ultra-deep J and Ks images secured with the near-infrared (NIR) GSAOI camera assisted by the multi-conjugate adaptive optics system GeMS at the GEMINI South Telescope in Chile, to obtain a (Ks, J - Ks) color-magnitude diagram (CMD) for the bulge globular cluster NGC 6624. We obtained the deepest and most accurate NIR CMD from the ground for this cluster, by reaching Ks ∼ 21.5, approximately 8 mag below the horizontal branch level. The entire extension of the Main Sequence (MS) is nicely sampled and at Ks ∼ 20 we detected the so-called MS "knee" in a purely NIR CMD. By taking advantage of the exquisite quality of the data, we estimated the absolute age of NGC 6624 (tage = 12.0 ± 0.5 Gyr), which turns out to be in good agreement with previous studies in the literature. We also analyzed the luminosity and mass functions of MS stars down to M ∼ 0.45 M⊙, finding evidence of a significant increase of low-mass stars at increasing distances from the cluster center. This is a clear signature of mass segregation, confirming that NGC 6624 is in an advanced stage of dynamical evolution.

Saracino, S., Dalessandro, E., Ferraro, F., Geisler, D., Mauro, F., Lanzoni, B., et al. (2016). ULTRA-DEEP GEMINI NEAR-INFRARED OBSERVATIONS of the BULGE GLOBULAR CLUSTER NGC 6624. THE ASTROPHYSICAL JOURNAL, 832(1), 48-62 [10.3847/0004-637X/832/1/48].

ULTRA-DEEP GEMINI NEAR-INFRARED OBSERVATIONS of the BULGE GLOBULAR CLUSTER NGC 6624

SARACINO, SARA;Dalessandro, E.;FERRARO, FRANCESCO ROSARIO;LANZONI, BARBARA;MIOCCHI, PAOLO;
2016

Abstract

We used ultra-deep J and Ks images secured with the near-infrared (NIR) GSAOI camera assisted by the multi-conjugate adaptive optics system GeMS at the GEMINI South Telescope in Chile, to obtain a (Ks, J - Ks) color-magnitude diagram (CMD) for the bulge globular cluster NGC 6624. We obtained the deepest and most accurate NIR CMD from the ground for this cluster, by reaching Ks ∼ 21.5, approximately 8 mag below the horizontal branch level. The entire extension of the Main Sequence (MS) is nicely sampled and at Ks ∼ 20 we detected the so-called MS "knee" in a purely NIR CMD. By taking advantage of the exquisite quality of the data, we estimated the absolute age of NGC 6624 (tage = 12.0 ± 0.5 Gyr), which turns out to be in good agreement with previous studies in the literature. We also analyzed the luminosity and mass functions of MS stars down to M ∼ 0.45 M⊙, finding evidence of a significant increase of low-mass stars at increasing distances from the cluster center. This is a clear signature of mass segregation, confirming that NGC 6624 is in an advanced stage of dynamical evolution.
2016
Saracino, S., Dalessandro, E., Ferraro, F., Geisler, D., Mauro, F., Lanzoni, B., et al. (2016). ULTRA-DEEP GEMINI NEAR-INFRARED OBSERVATIONS of the BULGE GLOBULAR CLUSTER NGC 6624. THE ASTROPHYSICAL JOURNAL, 832(1), 48-62 [10.3847/0004-637X/832/1/48].
Saracino, S.; Dalessandro, E.; Ferraro, F.R.; Geisler, D.; Mauro, F.; Lanzoni, B.; Origlia, L.; Miocchi, P.; Cohen, R.E.; Villanova, S.; Bidin, C. Moni
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/587267
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