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Gaia Focused Product Release: Sources from Service Interface Function image analysis: Half a million new sources in omega Centauri
Ist Teil von
Astronomy and astrophysics (Berlin), 2023-12, Vol.680, p.A35
Ort / Verlag
EDP Sciences
Erscheinungsjahr
2023
Quelle
EZB Electronic Journals Library
Beschreibungen/Notizen
Context.
Gaia
’s readout window strategy is challenged by very dense fields in the sky. Therefore, in addition to standard
Gaia
observations, full Sky Mapper (SM) images were recorded for nine selected regions in the sky. A new software pipeline exploits these Service Interface Function (SIF) images of crowded fields (CFs), making use of the availability of the full two-dimensional (2D) information. This new pipeline produced half a million additional
Gaia
sources in the region of the omega Centauri (
ω
Cen) cluster, which are published with this Focused Product Release. We discuss the dedicated SIF CF data reduction pipeline, validate its data products, and introduce their
Gaia
archive table.
Aims.
Our aim is to improve the completeness of the
Gaia
source inventory in a very dense region in the sky,
ω
Cen.
Methods.
An adapted version of
Gaia’s
Source Detection and Image Parameter Determination software located sources in the 2D SIF CF images. These source detections were clustered and assigned to new SIF CF or existing
Gaia
sources by
Gaia
s cross-match software. For the new sources, astrometry was calculated using the Astrometric Global Iterative Solution software, and photometry was obtained in the
Gaia
DR3 reference system. We validated the results by comparing them to the public
Gaia
DR3 catalogue and external
Hubble
Space Telescope data.
Results.
With this Focused Product Release, 526 587 new sources have been added to the
Gaia
catalogue in
ω
Cen. Apart from positions and brightnesses, the additional catalogue contains parallaxes and proper motions, but no meaningful colour information. While SIF CF source parameters generally have a lower precision than nominal
Gaia
sources, in the cluster centre they increase the depth of the combined catalogue by three magnitudes and improve the source density by a factor of ten.
Conclusions.
This first SIF CF data publication already adds great value to the
Gaia
catalogue. It demonstrates what to expect for the fourth
Gaia
catalogue, which will contain additional sources for all nine SIF CF regions.