Globular Clusters Lost by the Sagittarius Dwarf Spheroidal Galaxy

Arakelyan, N. R.; Пилипенко, С. В.; Шарина, М. Е.

doi:10.1134/s1990341320040021

Cited by 10 publications

(4 citation statements)

References 98 publications

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“…The rest have membership probabilities pmem 0.01, suggesting that there are no additional known GCs associated with the Sgr dwarf, in agreement with recent analyses (e.g. Arakelyan et al 2021;Johnson et al 2020). Our results do not support recent claims that NGC 5634 and 4147 trace ancient wraps of the stream (Bellazzini et al 2020).…”

Section: The Sagittarius and Orphan Streamssupporting

confidence: 63%

Identification of Sagittarius stream members in Angular Momentum space with Gaussian mixture techniques

Peñarrubia,

Petersen

2021

Preprint

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This paper uses Gaussian mixture techniques to dissect the Milky Way (MW) stellar halo in angular momentum space. Application to a catalogue of 5389 stars near the plane of the Sagittarius (Sgr) stream with full 6D phase-space coordinates supplied by Gaia EDR3 and SEGUE returns four independent dynamical components. The broadest and most populated corresponds to the 'smooth' MW halo. The narrowest and faintest contains 40 stars of the Orphan stream. We find a component with little or no angular momentum likely associated with the GSE substructure. We also identify 925 stars and 7 Globular Clusters with probabilities > 90% to be members of the Sgr stream. Comparison against N-body models shows that some of these members trace the continuation of the leading/trailing tails in the Southern/Northern hemispheres. The new detections span ∼ 800 • on the sky, thus wrapping the Galaxy twice.

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Section: The Sagittarius and Orphan Streamssupporting

confidence: 63%

Identification of Sagittarius stream members in Angular Momentum space with Gaussian mixture techniques

Peñarrubia,

Petersen

2021

Preprint

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“…dwarf galaxies). Then, the GCs in our Galaxy could have been stripped from extragalactic bodies (Arakelyan et al 2020). This scenario has been supported by observational evidence (e.g.…”

Section: Introductionsupporting

confidence: 70%

Heavy element abundances in galactic globular clusters

Schiappacasse-Ulloa,

Lucatello,

Cescutti

et al. 2024

A&A

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Globular clusters are considered key objects for understanding the formation and evolution of the Milky Way. In this sense, the characterisation of their chemical and orbital parameters can provide constraints on chemical evolution models of the Galaxy. We use the heavy element abundances of globular clusters to trace their overall behaviour in the Galaxy, with the aim to analyse potential relations between the hot H-burning and s-process elements. We measured the content of Cu I and s- and r-process elements (Y II, Ba II, La II, and Eu II) in a sample of 210 giant stars in 18 galactic globular clusters from high-quality UVES spectra. These clusters span a broad metallicity range and the sample is the largest that has been uniformly analysed to date, with respect to heavy elements in globular clusters. The Cu abundances did not show a considerable spread in the sample, nor any correlation with Na, indicating that the Na nucleosynthesis process does not affect the Cu abundance. Most GCs closely follow the Cu, Y, Ba, La, and Eu field stars' distribution, revealing a similar chemical evolution. The Y abundances in mid-metallicity regime GCs (-1.10 dex $<$ Fe/H $<$-1.80 dex) display a mildly significant correlation with the Na abundance, which ought to be further investigated. Finally, we do not find any significant difference between the n-capture abundances among GCs with either Galactic and extragalactic origins.

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“…Note that the proximity in the integral space does not imply that the objects line up on the same path on the sky plane, therefore the association with the stream should be examined in the space of observables -celestial coordinates, distances, PM and lineof-sight velocities. This connection was explored in a number of papers, e.g., Law & Majewski (2010b), Bellazzini et al (2020), Arakelyan et al (2020); however, these studies all relied on the old model of the Sgr stream from Law & Majewski (2010a), which was conceived before the more recent observations of its trailing arm, and does not match its features (primarily the distance to the apocentre). When using the model of the Sgr stream from Vasiliev et al (2021), which adequately matches all currently available observational constraints, we find that only the following clusters can be unambiguously associated with the Sgr stream: four clusters in the Sgr remnant -NGC 6715 (M 54, which sits at its centre), Terzan 7, Terzan 8, Arp 2, three clusters in the trailing arm -Pal 12, Whiting 1 and NGC 2419, and one faint cluster Ko 1, which previously lacked PM measurements (and still has no line-of-sight velocity data), but now coincides with the stream in position, distance and both PM components.…”

Section: Results For the Mean Parallaxes And Proper Motionsmentioning

confidence: 99%

Gaia EDR3 view on Galactic globular clusters

Vasiliev,

Baumgardt

2021

Preprint

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We use the data from Gaia Early Data Release 3 (EDR3) to study the kinematic properties of Milky Way globular clusters. We measure the mean parallaxes and proper motions (PM) for 170 clusters, determine the PM dispersion profiles for more than 100 clusters, uncover rotation signatures in more than 20 objects, and find evidence for radial or tangential PM anisotropy in a dozen richest clusters. At the same time, we use the selection of cluster members to explore the reliability and limitations of the Gaia catalogue itself. We find that the formal uncertainties on parallax and PM are underestimated by 10 − 20% in dense central regions even for stars that pass numerous quality filters. We explore the the spatial covariance function of systematic errors, and determine a lower limit on the uncertainty of average parallaxes and PM at the level 0.01 mas and 0.025 mas yr −1 , respectively. Finally, a comparison of mean parallaxes of clusters with distances from various literature sources suggests that the parallaxes (after applying the zero-point correction suggested by Lindegren et al. 2020b) are overestimated by ∼ 0.006 − 0.009 mas. Despite these caveats, the quality of Gaia astrometry has been significantly improved in EDR3 and provides valuable insights into the properties of star clusters.

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Globular Clusters Lost by the Sagittarius Dwarf Spheroidal Galaxy

Abstract: In this work a search was carried out for globular clusters belonging to the Sagittarius (Sgr) tidal stream using the analysis of spatial positions, radial velocities relative to the Galactic Standard of Rest (V GSR ),proper motions and ratio of "age -metallicity"

Cited by 10 publications

References 98 publications

Identification of Sagittarius stream members in Angular Momentum space with Gaussian mixture techniques

Identification of Sagittarius stream members in Angular Momentum space with Gaussian mixture techniques

Heavy element abundances in galactic globular clusters

Gaia EDR3 view on Galactic globular clusters

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