A Panchromatic View of the Bulge Globular Cluster NGC 6569

Journal
Date Issued
2019
Author(s)
Saracino, S.
•
•
Ferraro, F. R.
•
Lanzoni, B.
•
Geisler, D.
•
Cohen, R. E.
•
Bellini, A.
•
Vesperini, E.
•
Salaris, M.
•
•
•
•
Mauro, F.
•
Villanova, S.
•
Moni Bidin, C.
DOI
Abstract
We used high-resolution optical Hubble Space Telescope/WFC3 and multiconjugate adaptive optics assisted GEMINI GeMS/Gemini South Adaptive Optics Imager observations in the near-infrared (NIR) to investigate the physical properties of the globular cluster (GC) NGC 6569 in the Galactic bulge. We have obtained the deepest purely NIR color-magnitude diagram published so far for this cluster using ground-based observations, reaching K s ≈ 21.0 mag (two magnitudes below the main-sequence turn-off point). By combining the two data sets secured at two different epochs, we determined relative proper motions for a large sample of individual stars in the center of NGC 6569, allowing a robust selection of cluster member stars. Our proper motion analysis solidly demonstrates that, despite its relatively high metal content, NGC 6569 hosts some blue horizontal branch stars. A differential reddening map has been derived in the direction of the system, revealing a maximum color excess variation of about δ E(B-V)∼ 0.12 mag in the available field of view. The absolute age of NGC 6569 has been determined for the first time. In agreement with the other few bulge GCs with available age estimates, NGC 6569 turns out to be old, with an age of about 12.8 Gyr, and a typical uncertainty of 0.8-1.0 Gyr.

Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência, Tecnologia e Inovação (Brazil) and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina). Based on observations (GO 15232, PI: Ferraro) with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract 5-26555.

Volume
874
Issue
1
Start page
86
Uri
Url
Issn Identifier
0004-637X
Ads BibCode
2019ApJ...874...86S
Rights
open.access
File(s)
Loading...
Thumbnail Image
Name

30436-Saracino_2019_ApJ_874_86_P02.pdf

Description
Miur
Size

8.78 MB

Format

Adobe PDF

Checksum (MD5)

13202458fd46d4e702c7a0c78b78cba9

Loading...
Thumbnail Image
Name

30436-Saracino_2019_ApJ_874_86_P03.pdf

Description
Miur
Size

6.08 MB

Format

Adobe PDF

Checksum (MD5)

48df343b6be861e91f06ae0d244e9c07