GALACTOSEISMOLOGY: DISCOVERY OF VERTICAL WAVES IN THE GALACTIC DISK

By L. Widrow, S. Gardner, Brian Yanny, Scott Dodelson, Hsin-Yu Chen. 2012

187 citations recorded by the source corpus.

We present evidence for a Galactic North–South asymmetry in the number density and bulk velocity of solar neighborhood stars. The number density profile, which is derived from main-sequence stars in the Sloan Digital Sky Survey, shows a (North−South)/(North+South) deficit at |z| ≃ 400 pc and an excess at |z| ∼ 800 pc. The bulk velocity profile, which is derived from the Sloan Extension for Galactic Understanding and Exploration, shows a gradual trend across the Galactic midplane as well as smaller-scale features. We speculate that the North–South asymmetry, which has the appearance of a wavelike perturbation, is intrinsic to the disk. We explore the physics of this phenomenon through an analysis of the linearized Boltzmann and Poisson equations and through one-dimensional simulations. The perturbation may be excited by the passage of a satellite galaxy or dark matter subhalo through the Galactic disk, in which case we are witnessing a recent disk-heating event.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/f8697ed52b3f8efefc650d6ed2e8d82712d3a7e0

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Citations in the corpus

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 local dark matter density (2014, background): “For a disc surface density of Σb = 55 M pc−2, this gives δ|Kz|/2πG = δΣz ∼ 2.2 M pc−2, which is in excellent agreement with the number reported in Widrow et al. (2012).”
Chemodynamical evolution of the Milky Way disk II: Variations with Galactic radius and height above the disk plane (2014, background): “Indeed, the eff ct of satellites perturbing the MW disk has been linked to a number of observations of structure in the phase-space of local stars (e.g., Minchev et al. 2009; Gómez et al. 2012b,a, 2013; Widrow et al. 2012; Ramya et al. 2012).”
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).”
The influence of Sagittarius and the Large Magellanic Cloud on the stellar disc of the Milky Way Galaxy (2017, methodology): “7This is due to the exponential form of the disc profile and the fact that observational plots are positioned at the location of the Sun; thus one always probes larger Galactocentric distances towards the Anticenter.”
Mapping the Milky Way with LAMOST– III. Complicated spatial structure in the outer disc (2018, methodology): “Further compared to Widrow et al. (2012) at Z < 0 (the red line shown in Figure 7), we find that the residuals in our result is not consistent with these authors.”
The Wobbly Galaxy : kinematics north and south with RAVE red-clump giants (2013, background): “Thus, our three-dimensional velocity field confirms the recent one-dimensional results of Widrow et al. (2012) in which north–south differences in the velocities of SDSS stars suggested vertical waves in the Galactic disc.”
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).”
A-type stars in the Canada–France Imaging Survey – II. Tracing the height of the disc at large distances with Blue Stragglers (2018, background): “…et al. 2018; de Boer, Belokurov & Koposov 2018; Deason, Belokurov & Koposov 2018; Sheffield et al. 2018), while satisfying the constraints set by kinematics and amplitudes of the spatial number density counts in the solar neighbourhood (Widrow et al. 2012, but see also Schönrich & Dehnen 2018).”
RINGS AND RADIAL WAVES IN THE DISK OF THE MILKY WAY (2015, background): “Yanny & Gardner (2013) and Widrow et al. (2012) found an asymmetry in the number of stars above and below the Galactic plane, but the sign of the asymmetry oscillates with height above and below the disk.”