Resolving local and global kinematic signatures of satellite mergers with billion particle simulations

Hunt, Jason A. S.; Stelea, Ioana A.; Johnston, Kathryn V.; Gandhi, Suroor S.; Laporte, Chervin F. P.; Bédorf, Jeroen

doi:10.1093/mnras/stab2580

Cited by 47 publications

(77 citation statements)

References 80 publications

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“…They further show that the influence of self gravity slows the growth of the phase spiral. This result that can also be seen by comparing the phase spiral found by Bland-Hawthorn & Tepper-García (2021) with the one seen in the analytic models of Binney & Schönrich (2018) which winds up quickly (see also Hunt et al 2021).…”

Section: Galactic Seismologysupporting

confidence: 72%

The disturbed outer Milky Way disc

McMillan,

Petersson,

Tepper-Garcia

et al. 2022

Preprint

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The outer parts of the Milky Way's disc are significantly out of equilibrium. Using only distances and proper motions of stars from Gaia's Early Data Release 3, in the range |𝑏| < 10 • , 130 • < ℓ < 230 • , we show that for stars in the disc between around 10 and 14 kpc from the Galactic centre, vertical velocity is strongly dependent on the angular momentum, azimuth, and position above or below the Galactic plane. We further show how this behaviour translates into a bimodality in the velocity distribution of stars in the outer Milky Way disc. We use an 𝑁-body model of an impulse-like interaction of the Milky Way disc with a perturber similar to the Sagittarius dwarf to demonstrate that this mechanism can generate a similar disturbance. It has already been shown that this interaction can produce a phase spiral similar to that seen in the Solar neighbourhood. We argue that the details of this substructure in the outer galaxy will be highly sensitive to the timing of the perturbation or the gravitational potential of the Galaxy, and therefore may be key to disentangling the history and structure of the Milky Way.

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Section: Galactic Seismologysupporting

confidence: 72%

The disturbed outer Milky Way disc

McMillan,

Petersson,

Tepper-Garcia

et al. 2022

Preprint

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“…That study suggested that the phase spiral is a phase mixing signature after a perturbation. Further modelling has confirmed that the phase spiral can be a consequence of the Sagittarius dwarf galaxy tidal interaction (Binney & Schönrich 2018;Laporte et al 2019;Li & Shen 2020;Bland-Hawthorn & Tepper-García 2021;Hunt et al 2021;Gandhi et al 2021;Widmark et al 2021). Indeed, the estimated time of the perturbation roughly coincides with some of the previous pericenters of Sagittarius, estimated to ★ E-mail: begona01@ucm.es be between 200 and 1000 Myr ago (Law & Majewski 2010;Purcell et al 2011;Vasiliev & Belokurov 2020).…”

Section: Introductionmentioning

confidence: 90%

Phase spirals in cosmological simulations of Milky Way-sized galaxies

García-Conde

Roca-Fàbrega

Antoja

et al. 2021

Monthly Notices of the Royal Astronomical Society

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We study the vertical perturbations in the galactic disc of the Milky Way-size high-resolution hydrodynamical cosmological simulation named GARROTXA. We detect phase spirals in the vertical projection Z − VZ of disc’s stellar particles for the first time in this type of simulations. Qualitatively similar structures were detected in the recent Gaia data, and their origin is still under study. In our model the spiral-like structures in the phase space are present in a wide range of times and locations across the disc. By accounting for an evolving mix of stellar populations, we observe that, as seen in the data, the phase spirals are better observed in the range of younger-intermediate star particles. We measure the intensity of the spiral with a Fourier decomposition and find that these structures appear stronger near satellite pericenters. Current dynamical models of the phase spiral considering a single perturber required a mass at least of the order of 1010 M⊙, but all three of our satellites have masses of the order of ∼108 M⊙. We suggest that there are other mechanisms at play which appear naturally in our model such as the physics of gas, collective effect of multiple perturbers, and a dynamically cold population that is continuously renovated by the star formation Complementing collisionless isolated N-body models with the use of fully-cosmological simulations with enough resolution can provide new insights into the nature/origin of the phase spiral.

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“…by the authors is reproduced in state-of-the-art simulations of Milky-Way crossings by dwarf galaxies, but perturbations by the buckling bar and by arms also succeed in reproducing similar structures (see, e.g. Hunt et al 2021;Khoperskov et al 2019).…”

Section: Comparisons With Recent Results On Dust and Starsmentioning

confidence: 90%

Updated Gaia-2MASS 3D maps of Galactic interstellar dust

Lallement

Vergely

Babusiaux

et al. 2022

A&A

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Aims. Three-dimensional (3D) maps of Galactic interstellar dust are a tool for a wide range of uses. We aim to construct 3D maps of dust extinction in the Local Arm and surrounding regions. Methods. To do this, Gaia EDR3 photometric data were combined with 2MASS measurements to derive extinction towards stars with accurate photometry and relative uncertainties on EDR3 parallaxes of less than 20%. We applied our hierarchical inversion algorithm adapted to inhomogeneous spatial distributions of target stars to this catalogue of individual extinctions. Results. We present the updated 3D dust extinction distribution and provide an estimate of the error on integrated extinctions from the Sun to each area in the 3D map. The full computational area is similar to the one of the previous DR2 map, that is to say with a 6 × 6 × 0.8 kpc3 volume around the Sun. Due to the addition of fainter target stars, the volume in which the clouds can be reconstructed has increased. Due to the improved accuracy of the parallaxes and photometric data in EDR3, extinctions among neighbouring targets are more consistent, allowing one to reach an increased contrast in the dense areas, while cavity contours are more regular. We show several comparisons with recent results on dust and star distributions. The wavy pattern around the Plane of the dust concentrations is better seen and exists over large regions. Its mean vertical peak-to-peak amplitude is of the order of 300 pc; interestingly, it is similar to the vertical period of the spectacular snail-shaped stellar kinematical pattern discovered in Gaia data. Conclusions. The Gaia EDR3 catalogue allows for a significant improvement of the extinction maps to be made, both in extent and quality. The hierarchical technique confirms its efficiency in the inversion of massive datasets. Future comparisons between 3D maps of interstellar matter and stellar distributions may help to understand which mergers or internal perturbations have shaped the Galaxy within the first 3 kpc.

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Resolving local and global kinematic signatures of satellite mergers with billion particle simulations

Cited by 47 publications

References 80 publications

The disturbed outer Milky Way disc

The disturbed outer Milky Way disc

Phase spirals in cosmological simulations of Milky Way-sized galaxies

Updated Gaia-2MASS 3D maps of Galactic interstellar dust

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