Ralph Schönrich
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View article: Chemical evolution in nuclear stellar discs
Chemical evolution in nuclear stellar discs Open
Context . Nuclear stellar discs (NSDs) have been observed in the vast majority of barred disc galaxies, including the Milky Way. Their intense star formation is sustained by the intense gas inflows driven by their surrounding bars and freq…
View article: Pattern speed evolution of barred galaxies in TNG50
Pattern speed evolution of barred galaxies in TNG50 Open
Galactic bars are found in the majority of disc galaxies. They rotate nearly rigidly with an angular frequency called pattern speed. Previous idealised simulations have shown that bar pattern speed decreases with time due to dynamical fric…
View article: Comment on 'a slightly oblate dark matter halo revealed by a retrograde precessing Galactic disk warp' by Huang et al
Comment on 'a slightly oblate dark matter halo revealed by a retrograde precessing Galactic disk warp' by Huang et al Open
Huang et al. (2024) measured the derivative of the phase $ϕ_{\mathrm{w}}$ of the Galactic warp traced by classical Cepheids with respect to their age $τ$ and interpreted it as the warp precession rate $ω\equiv\mathrm{d}ϕ_{\mathrm{w}}/\math…
View article: JASMINE: Near-infrared astrometry and time-series photometry science
JASMINE: Near-infrared astrometry and time-series photometry science Open
The Japan Astrometry Satellite Mission for INfrared Exploration (JASMINE) is a planned M-class science space mission by the Institute of Space and Astronautical Science, the Japan Aerospace Exploration Agency. JASMINE has two main science …
View article: Radial Wave in the Galactic Disk: New Clues to Discriminate Different Perturbations
Radial Wave in the Galactic Disk: New Clues to Discriminate Different Perturbations Open
Decoding the key dynamical processes that shape the Galactic disk structure is crucial for reconstructing the Milky Way's evolution history. The second Gaia data release unveils a novel wave pattern in the $L_Z-\langle V_R\rangle$ space, b…
View article: Chemical Evolution in Nuclear Stellar Discs
Chemical Evolution in Nuclear Stellar Discs Open
Nuclear Stellar Discs (NSDs) have been observed in the vast majority of barred disc galaxies including the Milky Way. Their intense star formation is sustained by the intense gas inflows driven by their surrounding bars and frequently supp…
View article: JASMINE: Near-Infrared Astrometry and Time Series Photometry Science
JASMINE: Near-Infrared Astrometry and Time Series Photometry Science Open
Japan Astrometry Satellite Mission for INfrared Exploration (JASMINE) is a planned M-class science space mission by the Institute of Space and Astronautical Science, the Japan Aerospace Exploration Agency. JASMINE has two main science goal…
View article: A twisted and precessing Cepheid warp in the outer Milky Way disc
A twisted and precessing Cepheid warp in the outer Milky Way disc Open
We examine the Galactic warp in a sample of all classical Cepheids with Gaia DR3 radial velocity. In each radial bin, we determine (1) the inclined plane normal to the mean orbital angular momentum of the stars and (2) that best fitting th…
View article: Spiral arms and the angular momentum gap in Milky Way Cepheids
Spiral arms and the angular momentum gap in Milky Way Cepheids Open
The angular momentum distribution of classical Cepheids in the outer Milky Way disc is bimodal with a gap at $L_\mathrm{gap}=2950\, \rm{km\,s^{-1}}$ kpc, corresponding to $R=13\,$ kpc, while no similar feature has been found in the general…
View article: Age-morphology dependence of the Milky Way boxy/peanut bulge seen in Mira variables
Age-morphology dependence of the Milky Way boxy/peanut bulge seen in Mira variables Open
We analyse the distribution of Mira variable stars in the central region of the Milky Way. We find that with increasing period, i.e. decreasing age, the Miras shift towards negative Galactic longitudes ℓ. Comparing to a cosmological zoom s…
View article: Oscillating dynamical friction on galactic bars by trapped dark matter
Oscillating dynamical friction on galactic bars by trapped dark matter Open
The dynamic evolution of galactic bars in standard ΛCDM models is dominated by angular momentum loss to the dark matter haloes via dynamical friction. Traditional approximations to dynamical friction are formulated using the linearized col…
View article: Age distribution of stars in boxy/peanut/X-shaped bulges formed without bar buckling
Age distribution of stars in boxy/peanut/X-shaped bulges formed without bar buckling Open
Some barred galaxies, including the Milky Way, host a boxy/peanut/X-shaped bulge (BPX-shaped bulge). Previous studies suggested that the BPX-shaped bulge can either be developed by bar buckling or by vertical inner Lindblad resonance (vILR…
View article: The K2 Galactic Archaeology Program Data Release 3: Age-abundance Patterns in C1–C8 and C10–C18
The K2 Galactic Archaeology Program Data Release 3: Age-abundance Patterns in C1–C8 and C10–C18 Open
We present the third and final data release of the K2 Galactic Archaeology Program (K2 GAP) for Campaigns C1–C8 and C10–C18. We provide asteroseismic radius and mass coefficients, κ R and κ M , for ∼19,000 red giant stars, which translate …
View article: Capture of interstellar objects – II. By the Solar system
Capture of interstellar objects – II. By the Solar system Open
Capture of interstellar objects (ISOs) into the Solar system is dominated by ISOs with asymptotic incoming speeds $v_\infty \lt 4\,$km s−1. The capture rate is proportional to the ISO phase-space density in the Solar vicinity and does not …
View article: Metallicity-suppressed collapsars cannot be the dominant r-process source in the milky way
Metallicity-suppressed collapsars cannot be the dominant r-process source in the milky way Open
We develop a high-performance analytical model of Galactic Chemical Evolution, which accounts for delay time distributions and lock-up of stellar yields in a thermal-phased ISM. The model is capable of searching, for the first time, throug…
View article: Galactic bar resonances inferred from kinematically hot stars in <i>Gaia</i> EDR3
Galactic bar resonances inferred from kinematically hot stars in <i>Gaia</i> EDR3 Open
Using a numerical simulation of an isolated barred disc galaxy, we first demonstrate that the resonances of the inner bar structure induce more prominent features in the action space distribution for the kinematically hotter stars, which a…
View article: The K2 Galactic Archaeology Program Data Release 3: Age-abundance patterns in C1-C8, C10-C18
The K2 Galactic Archaeology Program Data Release 3: Age-abundance patterns in C1-C8, C10-C18 Open
We present the third and final data release of the K2 Galactic Archaeology Program (K2 GAP) for Campaigns C1-C8 and C10-C18. We provide asteroseismic radius and mass coefficients, $\kappa_R$ and $\kappa_M$, for $\sim 19,000$ red giant star…
View article: Age distribution of stars in boxy/peanut/X-shaped bulges formed without\n bar buckling
Age distribution of stars in boxy/peanut/X-shaped bulges formed without\n bar buckling Open
Some barred galaxies, including the Milky Way, host a boxy/peanut/X-shaped\nbulge (BPX-shaped bulge). Previous studies suggested that the BPX-shaped bulge\ncan either be developed by bar buckling or by vertical inner Lindblad resonance\n(v…
View article: Tree-ring structure of Galactic bar resonance
Tree-ring structure of Galactic bar resonance Open
Galaxy models have long predicted that galactic bars slow down by losing angular momentum to their postulated dark haloes. When the bar slows down, resonance sweeps radially outwards through the galactic disc while growing in volume, there…
View article: Resonance sweeping by a decelerating Galactic bar
Resonance sweeping by a decelerating Galactic bar Open
We provide the first quantitative evidence for the deceleration of the Galactic bar from local stellar kinematics in agreement with dynamical friction by a typical dark matter halo. The kinematic response of the stellar disc to a decelerat…
View article: Jeans modelling of the Milky Way’s nuclear stellar disc
Jeans modelling of the Milky Way’s nuclear stellar disc Open
The nuclear stellar disc (NSD) is a flattened stellar structure that dominates the gravitational potential of the Milky Way at Galactocentric radii $30 \lesssim R \lesssim 300\, {\rm pc}$. In this paper, we construct axisymmetric Jeans dyn…
View article: Resonance sweeping by a decelerating bar
Resonance sweeping by a decelerating bar Open
We provide the first quantitative evidence for the deceleration/growth of the Galactic bar from local stellar kinematics thus confirming dynamical friction within expectations for a typical dark matter halo. The kinematic response of the s…
View article: More than just a wrinkle: a wave-like pattern in Ug versus Lz from Gaia data
More than just a wrinkle: a wave-like pattern in Ug versus Lz from Gaia data Open
We present a newly found wave-like pattern in mean Galactocentric radial velocity ${\overline{U}_\mathrm{ g}}$ versus guiding centre radius Rg or angular momentum Lz of stars in the RV subsample of Gaia DR2. The short-wave pattern has a wa…
View article: The tilt of the local velocity ellipsoid as seen by Gaia
The tilt of the local velocity ellipsoid as seen by Gaia Open
The Gaia Radial Velocity Spectrometer (RVS) provides a sample of 7224 631 stars with full six-dimensional phase space information. Bayesian distances of these stars are available from the catalogue of Schönrich, McMillan & Eyer. We exploit…
View article: Distances and parallax bias in Gaia DR2
Distances and parallax bias in Gaia DR2 Open
We derive Bayesian distances for all stars in the radial velocity sample of Gaia DR2, and use the statistical method of Schönrich, Binney & Asplund to validate the distances and test the Gaia parallaxes. In contrast to other methods, which…
View article: The chemical evolution of r-process elements from neutron star mergers: the role of a 2-phase interstellar medium
The chemical evolution of r-process elements from neutron star mergers: the role of a 2-phase interstellar medium Open
Neutron star mergers (NM) are a plausible source of heavy r-process elements\nsuch as Europium, but previous chemical evolution models have either failed to\nreproduce the observed Europium trends for Milky Way thick disc stars (with\n[Fe/…
View article: On the Kinematic Signature of the Galactic Warp As Revealed By the LAMOST-TGAS Data
On the Kinematic Signature of the Galactic Warp As Revealed By the LAMOST-TGAS Data Open
Using a sample of about 123,000 stars with accurate 3D velocity measurements from the LAMOST-TGAS data, we confirm the kinematic signature of the Galactic warp recently found by Schönrich & Dehnen. The data reveal a clear trend of increasi…
View article: The origin of the Gaia phase-plane spiral
The origin of the Gaia phase-plane spiral Open
A simple model is presented of the formation of the spiral the (z,v_z) phase plane of solar-neighbourhood stars that was recently discovered in Gaia data. The key is that the frequency Omega_z at which stars oscillate vertically depends on…
View article: Warp, waves, and wrinkles in the Milky Way
Warp, waves, and wrinkles in the Milky Way Open
We derive unbiased distance estimates for the Gaia-TGAS dataset by correcting\nfor the bias due to the distance dependence of the selection function, which we\nmeasure directly from the data. From these distances and proper motions, we\nes…