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Deriving physical parameters of unresolved star clusters. VII. Adaptive aperture photometry of the M31 PHAT star clusters
This work is the seventh study in a series dedicated to investigating
degeneracies of simultaneous age, mass, extinction, and metallicity
determinations of partially resolved or unresolved star clusters with Hubble
Space Telescope broadband aperture photometry. In the sixth work (hereafter,
Paper I), it was demonstrated that the adaptive aperture photometry, performed
to avoid the majority of the projected foreground and background stars falling
within the apertures, gives more consistent colour indices for star clusters.
In this study, we aim to supplement the homogeneous multi-colour aperture
photometry results published in Paper~I and provide a complete M31 Panchromatic
Hubble Andromeda Treasury (PHAT) survey star cluster photometry catalogue for
further analysis. Following Paper I, we used a two-aperture approach for
photometry. The first aperture is the standard one used to measure total
cluster fluxes. The second (smaller) aperture is introduced to avoid the bright
foreground and background stars projecting onto the clusters. We selected the
radii of smaller apertures to be larger than the half-light radii of the
clusters. We present the second part of the star cluster aperture photometry
catalogues for a sample of 1477 star clusters from the M31 PHAT survey not
covered in Paper I. Compared to the M31 PHAT star cluster aperture photometry
catalogue published by Johnson et al., adjustments were made to the cluster
centre coordinates, aperture sizes, and sky background levels.Comment: 8 pages, 8 figures, accepted in A&