Mission Overview
Hubble Space Telescope Atlases of Cluster Kinematics (HACKS)
Primary Investigator: Mattia Libralato
HLSP Authors: Mattia Libralato
Released: 2022-06-22
Updated: 2024-04-05
Primary Reference(s): Libralato et al. 2022
DOI: 10.17909/jpfd-2m08
Citations: See ADS statistics
Source Data:
- HST Proposal GO 13297
- See HLSP Read Me for additional GO programs
Overview
A number of studies based on data collected by the Hubble Space Telescope (HST) GO-13297 program “HST Legacy Survey of Galactic Globular Clusters: Shedding UV Light on Their Populations and Formation" have investigated the photometric properties of a large sample of Galactic globular clusters and revolutionized our understanding of their stellar populations. In this project, the authors expand previous studies by focusing on the stellar clusters’ internal kinematics. The authors computed proper motions for stars in 56 globular clusters and one open cluster by combining the GO-13297 images with archival HST data. The astro-photometric catalogs released with this paper represent the most complete and homogeneous collection of proper motions of stars in the cores of stellar clusters to date, and expand the information provided by the current (and future) Gaia data releases to much fainter stars and into the crowded central regions. At the dawn of a new era in astronomy with the first light of the James Webb Space Telescope (JWST), the legacy that these proper-motion catalogs offer is further enhanced, since they can serve as an important astrometric benchmark for JWST-based data reduction and tools.
Update 2024-04-05: The WFC3/UVIS F814W photometry of the clusters NGC 1851, NGC 5904, NGC 5927, NGC 6341, NGC 6541, NGC 6656, NGC 6681, NGC 6752, NGC 6791, NGC 7078 showed an unexpected zero-point. The issue likely arose from the poor quality of the DRC-based, aperture-photometry catalogs used for the photometry registration on to the VEGAmag system. The team fixed the VEGAmag zero-point for all these catalogs except for NGC 5904, for which a small zero-point is still present.
Data Products
Photometric and proper motion catalogs are located in subdirectories called "catalogs/<cluster>". The photometric catalogs are named according to the following convention:
hlsp_hacks_hst_<inst>_<target>_<opt-elem>_v1.0_phot-catalog-<epoch>.<ext>
where:
- <inst> is the HST instrument used for the observation, e.g., "acs-wfc", "acs-hrc", or "wfc3".
- <target> is the target cluster.
- <opt-elem> is the optical element used for the observation.
- <epoch> is the observation epoch, one of "ep1", "ep2", "ep3 or "ep4".
- <ext> is the file extension, either ".fits" or ".txt"
Proper motion catalog files are named according to the following convention:
hlsp_hacks_hst_<inst>_<target>_multi_v1.0_pm-catalog.<ext>
where:
- <inst> is the HST instrument used for the observation.
- <target> is the target cluster.
- <ext> is the file extension, either ".fits" or ".txt".
Velocity dispersion catalogs are named according to the following convention:
hlsp_hacks_hst_<inst>_<target>_multi_v1.0_vdisp.txt
where:
- <inst> is the HST instrument used for the observation.
- <target> is the target cluster, and includes "all" for a catalog for all clusters.
Data file types:
| _phot-catalog | photometric catalog |
| _pm-catalog | proper motion catalog |
| _vdisp.txt | velocity dispersions based on the propert motions |
Data Access
A list of the observations used in the project is found here, and are appended to the Read Me file linked above. Entries marked with ‘*' corresponds to data sets not used in the computation of the proper motions.
All data products are available in the following table. A file containing the velocity dispersion catalogs for all clusters is included at the bottom ("All").
