J/A+A/658/A51 New M31 star cluster candidates (Wang+, 2022)
Identification of new M31 star cluster candidates from PAndAS images using
convolutional neural networks.
Wang S., Chen B., Ma J., Long Q., Yuan H., Liu D., Zhou Z., Liu W., Chen J.,
He Z.
<Astron. Astrophys. 658, A51 (2022)>
=2022A&A...658A..51W 2022A&A...658A..51W (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Associations, stellar ; Photometry ; Optical
Keywords: galaxies: star clusters: general -
galaxies: star clusters: individual: M31
Abstract:
Identification of new star cluster candidates in M 31 is fundamental
for the study of the M 31 stellar cluster system. The machine-learning
method convolutional neural network (CNN) is an efficient algorithm
for searching for new M 31 star cluster candidates from tens of
millions of images from wide-field photometric surveys.
We search for new M 31 cluster candidates from the high-quality g- and
i-band images of 21 245 632 sources obtained from the Pan-Andromeda
Archaeological Survey (PAndAS) through a CNN.
We collected confirmed M 31 clusters and noncluster objects from the
literature as our training sample. Accurate double-channel CNNs were
constructed and trained using the training samples. We applied the CNN
classification models to the PAndAS g- and i-band images of over 21
million sources to search new M 31 cluster candidates. The CNN
predictions were finally checked by five experienced human inspectors
to obtain high-confidence M 31 star cluster candidates.
After the inspection, we identified a catalogue of 117 new M 31
cluster candidates. Most of the new candidates are young clusters that
are located in the M 31 disk. Their morphology, colours, and
magnitudes are similar to those of the confirmed young disk clusters.
We also identified eight globular cluster candidates that are located
in the M 31 halo and exhibit features similar to those of confirmed
halo globular clusters. The projected distances to the M 31 centre for
three of them are larger than 100kpc.
Description:
File table2.dat contains 117 M31 star cluster candidates and their
coordinates, magnitudes, projected radii, ellipticities, position
angles, summed scores.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 72 117 Cluster names, positions and parameters
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name Name of the star cluster candidate,
CandidateNNN
14 I1 h RAh Right Ascension (J2000)
16- 17 I2 min RAm Right Ascension (J2000)
19- 24 F6.3 s RAs Right Ascension (J2000)
26 A1 --- DE- Declination sign (J2000)
27- 28 I2 deg DEd Declination (J2000)
30- 31 I2 arcmin DEm Declination (J2000)
33- 37 F5.2 arcsec DEs Declination (J2000)
39- 44 F6.3 mag gmag g-band magnitude
46- 51 F6.3 mag imag i-band magnitude
53- 57 F5.1 kpc Rproj Projected radii from the M31 centre
59- 62 F4.2 --- ell Ellipticity
64- 69 F6.2 deg PA [] Position angle
71- 72 I2 --- Score Summed scores by visual inspectors
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Acknowledgements:
Shoucheng Wang, scwang(at)nao.cas.cn
(End) Patricia Vannier [CDS] 16-Nov-2021