Moving groups across Galactocentric radius with Gaia DR3

Lucchini, Scott; Pellett, Emil; D'Onghia, Elena; Aguerri, J. Alfonso L.

doi:10.48550/arxiv.2206.10633

Cited by 3 publications

(4 citation statements)

References 52 publications

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“…Large-scale spectroscopic and photometric surveys, even with sparse spatial coverage, already hinted at streaming or bulk motion in the disc, with trends in both Galactic height and radius (Widrow et al 2012;Carlin et al 2013;Williams et al 2013;Bovy et al 2015;Khanna et al 2019a;Gaia Collaboration et al 2018). The first opportunity to study this in a homogeneous manner presented itself soon after the second Gaia data release (Gaia DR2), using which, Antoja et al (2018) discovered largescale diagonal ridges in the V ϕ -R density space, which are even more striking when mapped by the galactocentric velocities, V R and V Z (Ramos et al 2018;Fragkoudi et al 2019;Khanna et al 2019;Laporte et al 2019;Bernet et al 2022;Lucchini et al 2022). Additionally, Antoja et al (2018) also discovered an overdensity, known commonly as the phase-spiral, in the z-V Z plane, when mapped by V R or V Z .…”

Section: Introductionmentioning

confidence: 99%

A new resonance-like feature in the outer disc of the Milky Way

Drimmel¹,

Khanna²,

D’Onghia³

et al. 2023

A&A

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Modern astrometric and spectroscopic surveys have revealed a wealth of structure in the phase space of stars in the Milky Way, with evidence of resonance features and non-equilibrium processes. Using the third Gaia data release, we present evidence of a new resonance-like feature in the outer disc of the Milky Way. The feature is most evident in the angular momentum distribution of the young classical Cepheids, a population for which we can derive accurate distances over much of the Galactic disc. We then searched for similar features in the outer disc using a much larger sample of red giant stars, as well as a compiled list of over 31 million stars with spectroscopic line-of-sight velocity measurements. While much less evident in these two older samples, the distribution of stars in action-configuration space suggests that resonance features are present here as well. The position of the feature in action-configuration space suggests that the new feature may be related to the Galactic bar, but other possibilities are discussed.

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Section: Introductionmentioning

confidence: 99%

A new resonance-like feature in the outer disc of the Milky Way

Drimmel¹,

Khanna²,

D’Onghia³

et al. 2023

A&A

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show abstract

“…These local overdensities, proposed to be induced by dynamical resonances, past perturbations, and/or non-axisymmetric features of the Milky Way, are all prime targets of research and provide valuable insights into the formation and evolution of the galactic disk (see, e.g., Appendix B of Trick et al (2019) for a short review). New moving groups are still being discovered thanks to constantly improving methodologies (Ramos et al 2018;Bernet et al 2022;Lucchini et al 2022). Identifying these overdensities in the disk with high confidence requires careful treatment of the uncertainties, as the structures will most likely be accompanied by strong background noise.…”

Section: Interpretation and Conclusionmentioning

confidence: 99%

“…Identifying these overdensities in the disk with high confidence requires careful treatment of the uncertainties, as the structures will most likely be accompanied by strong background noise. Lucchini et al (2022), for example, incorporated various measurement uncertainties with wavelet transforms, which is another promising way to maximize unsupervised data analysis outputs.…”

Section: Interpretation and Conclusionmentioning

confidence: 99%

Robust Clustering of the Local Milky Way Stellar Kinematic Substructures with Gaia eDR3

Ou¹,

Necib²,

Frebel³

2022

Preprint

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We apply the clustering algorithm HDBSCAN on the Gaia early third data release astrometry combined with the Gaia second data release radial velocity measurements of almost 5.5 million stars to identify the local stellar kinematic substructures in the solar neighborhood. Understanding these structures helps build a more complete picture of the formation of the Milky Way, as well as an empirical phase space distribution of dark matter that would inform detection experiments. The main goal of this study is to provide a list of the most stable clusters, by taking into account the measurement uncertainties and studying the stability of the clustering results. We apply the clustering algorithm in two spaces, in velocity space in order to study recently accreted structures, and in action-angle space to find phase-mixed structures. We find 1405 (497) stars in 23 (6) robust clusters in velocity space (action-angle space) that are consistently not associated with noise. They are attributed to the known structures: the Gaia Sausage-Enceladus, the Helmi Stream, and globular cluster NGC 3201 are found in both spaces, while NGC 104 and the thick disk (Sequoia) are identified in velocity space (actionangle space). We discuss the kinematic properties of these structures, and cross match them with APOGEE DR17 and LAMOST DR6 to study whether many of the small clusters belong to a similar larger cluster based on their chemical abundances. Although we do not identify any new structures, we find that the HDBSCAN member selection of already known structures is unstable to input kinematics of the stars when resampled within their uncertainties. We therefore present the most stable subset of local kinematic structures, which are consistently identified by the clustering algorithm, and emphasize the need to take into account error propagation during both the manual and automated identification of stellar structures, both for existing ones as well as future discoveries.

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“…Large scale spectroscopic and photometric surveys, even with sparse spatial coverage, already hinted at streaming or bulk motion in the disc, with trends in both Galac-tic height and radius (Widrow et al 2012;Carlin et al 2013;Williams et al 2013;Bovy et al 2015;Khanna et al 2019a;Gaia Collaboration et al 2018). The first opportunity to study this in a homogeneous manner presented itself soon after the release of Gaia DR2, using which Antoja et al (2018) discovered the presence of large-scale diagonal ridges in the V φ -R density space, which are even more striking when mapped by the Galactocentric velocities, V R and V Z (Ramos et al 2018;Fragkoudi et al 2019;Khanna et al 2019;Laporte et al 2019;Bernet et al 2022;Lucchini et al 2022). Additionally, Antoja et al (2018) also discovered an overdensity, known commonly as the phasespiral, in the z-V Z plane, when mapped by V R or V Z .…”

Section: Introductionmentioning

confidence: 99%

A new resonance-like feature in the outer disc of the Milky Way

Drimmel¹,

Khanna²,

D’Onghia³

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

Modern astrometric and spectroscopic surveys have revealed a wealth of structure in the phase space of stars in the Milky Way, with evidence of resonance features and non-equilibrium processes. Using Gaia DR3 , we present evidence of a new resonance-like feature in the outer disc of the Milky Way. The feature is most evident in the angular momentum distribution of the young Classical Cepheids, a population for which we can derive accurate distances over much of the Galactic disc. We then search for similar features in the outer disc using a much larger sample of red giant stars, as well as a compiled list of over 31 million stars with spectroscopic line-of-sight velocity measurements. While much less evident in these two older samples, the distribution of stars in action-configuration space suggests that resonance features are present here as well. The position of the feature in action-configuration space suggests that the new feature may be related to the Galactic bar, but other possibilities are discussed.

show abstract

Moving groups across Galactocentric radius with Gaia DR3

Cited by 3 publications

References 52 publications

A new resonance-like feature in the outer disc of the Milky Way

A new resonance-like feature in the outer disc of the Milky Way

Robust Clustering of the Local Milky Way Stellar Kinematic Substructures with Gaia eDR3

A new resonance-like feature in the outer disc of the Milky Way

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