J/A+A/692/A194 New catalog of GLIMPSE Galactic star clusters (Gupta+, 2024)
Obscured star clusters in the Inner Milky Way.
How many massive young clusters are still awaiting detection?
Gupta A., Ivanov V.D., Preibisch T., Minniti D.
<Astron. Astrophys. 692, A194 (2024)>
=2024A&A...692A.194G 2024A&A...692A.194G (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Associations, stellar ; Photometry, infrared
Keywords: Galaxy: disk - open clusters and associations: general -
Galaxy: stellar content - Galaxy: structure
Abstract:
Milky Way star clusters provide important clues for the history of
the star formation in our Galaxy. However, the dust in the disk and
the innermost regions hides them from the observers.
Our goal is twofold. First, to detect new clusters - we apply the
newest methods for the detection of clustering with the best available
wide-field sky surveys in the mid-infrared because they are the least
affected by extinction. Second, we address the question of cluster
detection's completeness, for now limiting it to the most massive star
clusters.
This search is based on the mid-infrared Galactic Legacy Infrared
Mid-Plane Survey Extraordinaire (GLIMPSE), to minimize the effect of
dust extinction. The search Ordering Points To Identify the Clustering
Structure (OPTICS) clustering algorithm is applied to identify
clusters, after excluding the bluest, presumably foreground sources,
to improve the cluster-to-field contrast. The success rate for cluster
identification is estimated with a semi-empirical simulation that adds
clusters, based on the real objects, to the point source catalog, to
be recovered later with the same search algorithm that was used in the
search for new cluster candidates. As a first step, this is limited to
the most massive star clusters with a total mass of ∼10^4 M_sun.
Our automated search, combined with inspection of the color-magnitude
diagrams and images yielded 659 cluster candidates; 106 of these
appear to have been previously identified, suggesting that a large
hidden population of star clusters still exists in the inner Milky
Way. However, the search for the simulated supermassive clusters
achieves a recovery rate of 70-95%, depending on the distance and
extinction toward them.
The new candidates - if confirmed - indicate that the Milky Way still
harbors a sizeable population of still unknown clusters. However, they
must be objects of modest richness, because our simulation indicates
that there is no substantial hidden population of supermassive
clusters in the central region of our Galaxy.
Description:
We compiled a new catalog of stellar clusters from the Spitzer/GLIMPSE
data. There are 659 cluster candidates; 106 of which were already
discovered. Their provisional radius and number of members calculated
from clustering algorithm is also provided. The last column provides
SIMBAD IDs for already known clusters.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 114 659 The catalog of GLIMPSE clusters
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Object Identifier of the object (GIPM NNN)
10- 20 F11.7 deg GLON Galactic Longitude
22- 31 F10.7 deg GLAT Galactic Latitude
33- 37 F5.2 --- overdens Overdensity
40- 53 F14.12 deg Raddeg Radius in degrees
56- 58 F3.1 arcmin Radarcmin Radius in arcmin
61- 63 I3 --- Nstars Number of stars in the cluster
66-114 A49 --- ONames Existing IDs from SIMBAD
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Acknowledgements:
Akash Gupta, agupta(at)ph1.uni-koeln.de
(End) Akash Gupta [PH1, Univ Koeln, Germany], Patricia Vannier [CDS] 05-Nov-2024