Newly detected open clusters in the Galactic disk using <i>Gaia</i> EDR3

Xu, Ye; Wu, Zhenyu; Lin, Zuzhang; Liu, D. J.; Li, Yingjie

doi:10.1051/0004-6361/202243091

“…This pair was first proposed as a candidate binary cluster by FitzGerald and Moffat [28]. The putative components have very different ages: Gaia-derived ages for Haffner 10 range between 1.1 Gyr [22] and 5 Gyr [26], while Gaia studies on Czernik 29 report values between 0.08 Gyr [29] and 0.17 Gyr [5]. Therefore, they cannot be a primordial pair due to their age difference.…”

Section: Methodsmentioning

confidence: 99%

The Effect of Age on the Grouping of Open Clusters: II—Are There Old Binary Clusters?

Casado¹

2022

Universe

1

0

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In the present study, we continue testing the Primordial Group hypothesis (Casado 2022), which postulates that only sufficiently young open clusters can be binary or multiple, and old clusters are essentially single. To this end, we revisit all the remaining binary cluster candidates in the Galaxy having at least one cluster older than 100 Myr through Gaia data and careful revision of the literature. We found no convincing case for an old binary system among the 120 pairs/groups revised. Most of the pairs are optical pairs or flyby encounters. However, we found three dubious pairs that could falsify the title hypothesis upon further research. We also found two possible primordial pairs older than expected. Our results confirm that the vast majority of binary/multiple OCs in the Galaxy, if not all, are of primordial origin and are not stable for a long time. This finding is in line with similar studies of the Magellanic Clouds and theoretical N-body simulations in the Galaxy. The pairs of OCs in these groups are generally not binary systems since they are not gravitationally bound. We also point out some inconsistencies in previous works and databases, such as false open clusters and duplicities.

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“…To build a catalog of new SCs, we cross-matched with previously published sources. The list of references included the works of Cantat-Gaudin et al (2020a); Liu & Pang (2019);Ferreira et al (2019Ferreira et al ( , 2020Ferreira et al ( , 2021; Qin et al (2021); He et al (2021He et al ( , 2022b; Hunt & Reffert (2021); Casado (2021); Jaehnig et al (2021); Dias et al (2021); Li et al (2022); Hao et al (2022);Castro-Ginard et al (2022). In our method we have removed known SCs from the search results, and we also made a roughly cross-match between these published catalogs.…”

Section: Stellar Data and Reference Cluster Catalogsmentioning

confidence: 99%

“…Liu & Pang 2019;Sim et al 2019;Cantat-Gaudin et al 2019;Castro-Ginard et al 2019;Kounkel et al 2020;Castro-Ginard et al 2020;Ferreira et al 2020Ferreira et al , 2021He et al 2021He et al , 2022bHunt & Reffert 2021). Based on the early third data release (Gaia Collaboration et al 2021, EDR3), researchers have reported more than 1,500 new OCs and candidates (Castro-Ginard et al 2022;Hao et al 2022;He et al 2022a) so far, which covered the distance range from 100 pc to 5 kpc.…”

Section: Introductionmentioning

confidence: 99%

Unveiling hidden stellar aggregates in the Milky Way: 1656 new star clusters found in Gaia EDR3

He¹,

Liu²,

Luo³

et al. 2022

Preprint

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We report 1,656 new star clusters found in the Galactic disk (|b|<20 degrees) beyond 1.2 kpc, using Gaia EDR3 data. Based on an unsupervised machine learning algorithm, DBSCAN, and followed our previous studies, we utilized a unique method to do the data preparation and obtained the clustering coefficients, which proved to be an effective way to search blindly for star clusters. We tabulated the physical parameters and member stars of the new clusters, and presented some interesting examples, including a globular cluster candidate. The cluster parameters and member stars are available at CDS via anonymous ftp to https://cdsarc.cds.unistra.fr/ftp/vizier.submit//he22c. We examined the new discoveries and discussed their statistical properties. The proper motion dispersions and radii of star clusters are the same as the previously reported. The new clusters beyond 1.2 kpc are older than those in the solar neighborhood, and the new objects found in the third Galactic quadrant present the lowest line-of-sight extinctions. Combined with our previous results, the total population of new clusters and candidates detected through our method is 2,541, corresponding to 55% of all newly published clusters in the Gaia era. The number of cataloged Gaia star clusters was also increased to nearly six thousand. In the near future, it is necessary to make an unified confirmation and member star determination for all reported clusters.

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“…Recently, the Gaia mission of the European Space Agency has provided its third data release (DR3), which includes astrometry and broadband photometry for a total of 1.8 billion objects (Gaia Collaboration et al 2022). Together with a large number of DCEPs (Pietrukowicz et al 2021) and OCs (Cantat-Gaudin et al 2018Castro-Ginard et al 2018Hao et al 2020Hao et al , 2022a, a census of OC classical Cepheids (OC-DCEPs) is compiled in the present work. With the precise distances afforded by cluster-averaged parallaxes, our aim is to provide an independent calibration of the PW relation in the Gaia bands.…”

Section: Introductionmentioning

confidence: 99%

Calibrating the Cepheid Period–Wesenheit Relation in the Gaia Bands Using Galactic Open-cluster Cepheids

Lin

¹

,

Xu

²

,

Hao

³

et al. 2022

ApJ

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Establishing the period–Wesenheit relation requires independent and accurate distance measurements of classical Cepheids (DCEPs). The precise distances provided by associated open clusters independently calibrate the period–Wesenheit relations of DCEPs. 51 DCEPs associated with open clusters are compiled using the constraints of five-dimensional astrometric information. By directly using Gaia data release 3 parallaxes, the period–Wesenheit relation in the Gaia G band is calibrated as W G = ( − 3.06 ± 0.11 ) log P + ( − 2.96 ± 0.10 ) . Compared with the results derived from directly adopting the DCEP parallaxes or from using distance moduli, the Wesenheit magnitudes based on the cluster-averaged parallaxes exhibit a tighter relation with the period. Besides, there is a systematic offset between the observed Wesenheit absolute magnitudes of distant open-cluster DCEPs and their fitted magnitudes. After considering a parallax zeropoint correction, the systematic offset can be reduced, yielding a probably better period–Wesenheit relation of W G = ( − 2.94 ± 0.12 ) log P + ( − 2.93 ± 0.11 ) .

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Newly detected open clusters in the Galactic disk using Gaia EDR3

Cited by 40 publications

References 58 publications

The Effect of Age on the Grouping of Open Clusters: II—Are There Old Binary Clusters?

The Effect of Age on the Grouping of Open Clusters: II—Are There Old Binary Clusters?

Unveiling hidden stellar aggregates in the Milky Way: 1656 new star clusters found in Gaia EDR3

Calibrating the Cepheid Period–Wesenheit Relation in the Gaia Bands Using Galactic Open-cluster Cepheids

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