Vertical density waves in the Milky Way disc induced by the Sagittarius dwarf galaxy

By F. G'omez, I. Minchev, Brian W. O'Shea, Timothy C. Beers, James S. Bullock, C. Purcell. 2012

166 citations recorded by the source corpus.

Recently, Widrow and collaborators announced the discovery of vertical density waves in the Milky Way disk. Here we investigate a scenario where these waves were induced by the Sagittarius dwarf galaxy as it plunged through the Galaxy. Using numerical simulations, we find that the Sagittarius impact produces North-South asymmetries and vertical wave-like behavior that qualitatively agrees with what is observed. The extent to which vertical modes can radially penetrate into the disc, as well as their amplitudes, depend on the mass of the perturbing satellite. We show that the mean height of the disc is expected to vary more rapidly in the radial than in the azimuthal direction. If the observed vertical density asymmetry is indeed caused by vertical oscillations, we predict radial and azimuthal variations of the mean vertical velocity, correlating with the spatial structure. These variations can have amplitudes as large as 8 km/s.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/aba9cbba9e7674ae664eb0debc7055a9c1ac8c44

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Citations in the corpus

RINGS AND RADIAL WAVES IN THE DISK OF THE MILKY WAY (2015, background): “Our results roughly resemble the radial and vertical oscillations expected from the infall of the Sagittarius dwarf galaxy (Gómez et al. 2013).”
Constraining the Milky Way assembly history with Galactic Archaeology (2016, background): “Gómez et al. (2013) showed that just such a disturbance from the Sagittarius dwarf galaxy can explain the recent discovery of vertical waves near the Sun in SEGUE (Widrow et al., 2012) and RAVE (Williams et al., 2013).”
The structure and dynamical evolution of the stellar disc of a simulated Milky Way-mass galaxy (2016, background): “…see e.g. Minchev et al. 2012), (3) perturbation of satellites and sub-halos (e.g. Quinn et al. 1993; Kazantzidis et al. 2008; Purcell et al. 2009; Gómez et al. 2013), and (4) scattering by giant molecular clouds (GMCs) or star clusters (e.g. Spitzer & Schwarzschild 1951, 1953; Aumer et al. 2016).”
The GALAH survey and Gaia DR2: dissecting the stellar disc’s phase space by age, action, chemistry, and location (2018, background): “…are observed (e.g. Newberg et al. 2002; RochaPinto et al. 2004; Newberg et al. 2007) and these have been interpreted in terms of corrugations and waves triggered by a passing satellite (e.g. Quillen et al. 2009; Purcell et al. 2011; Widrow et al. 2012; Gómez et al. 2013; de la Vega et al. 2015).”
Red Clump Stars from LAMOST II: the outer disc of the Milky Way (2017, background): “Minor mergers may also affect the outer discs and induce substructures in stellar density as well as in kinematics (Gómez et al. 2013, 2016).”
Chemodynamical evolution of the Milky Way disk - I. The solar vicinity (2012, background): “Evidence for satellite-disk encounters can be found in structure in the phase-space of MW disk stars (e.g., Minchev et al. 2009; Gómez et al. 2013; Gómez et al. 2012c), which can last for as long as∼4 Gyr (Gómez et al., 2012b).”
Vertical disc heating in Milky Way-sized galaxies in a cosmological context (2015, background): “…motion from star scattering off Giant molecular clouds (GMCs) (Carlberg 1987), other massive bodies, or in the form of vertical breathing waves induced by a bar and spiral arms (Masset & Tagger 1997; Faure et al. 2014; Monari et al. 2015) or from satellite interactions (Gómez et al. 2013).”
The influence of Sagittarius and the Large Magellanic Cloud on the stellar disc of the Milky Way Galaxy (2017, background): “…& White 1999; Villalobos & Helmi 2008; Purcell, Bullock & Kazantzidis 2010), cause ringing in the u − v and E − Lz planes (Minchev et al. 2009; Gómez et al. 2012), or produce vertical oscillations (Gómez et al. 2013; Widrow et al. 2014; Gómez et al. 2017) that are coupled with motions…”
The local dark matter density (2014, background): “These same surveys have recently found evidence for vertical density waves in the Milky Way disc (Widrow et al., 2012; Williams et al., 2013; Yanny & Gardner, 2013), perhaps caused by the recent Sagittarius dwarf merger (Gómez et al., 2013).”
A-type stars in the Canada–France Imaging Survey – II. Tracing the height of the disc at large distances with Blue Stragglers (2018, background): “…migration is expected to be less pronounced than in the case of a flare caused by disc–satellite impacts (Ibata & Razoumov 1998; Velazquez & White 1999; Kazantzidis et al. 2008; Villalobos & Helmi 2008; Bournaud, Elmegreen & Martig 2009; Purcell, Bullock & Kazantzidis 2010; Gómez et al. 2013).”
The Wobbly Galaxy : kinematics north and south with RAVE red-clump giants (2013, background): “Indeed, Gómez et al. (2013) further suggest that such vertical waves may have been excited by the Sagittarius dwarf as it passed through the disc.”
Galaxy Masses: A Review (2013, background): “In particular, such perturbations may have arisen from a passing satellite or dark matter subhalo Widrow et al. (2012); Gómez et al. (2013).”