Action-based distribution function modelling for constraining the shape of the Galactic dark matter halo

Hattori, Kohei; Valluri, Monica; Vasiliev, Eugene

doi:10.48550/arxiv.2012.03908

Cited by 14 publications

(24 citation statements)

References 80 publications

(145 reference statements)

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“…The errors are randomly generated from independent Gaussian distributions on each quantity for each star particle with standard deviations determined by characteristic or expected errors for Gaia and DESI observations. The Gaia heliocentric distance error is the same for all star particles at = 0.1107 (Hattori et al 2020). The Gaia proper motion errors ( * , ) are a function of 2 Gaia Expected Science Performance https://www.cosmos.esa.int/ web/gaia/science-performance -and also by Eq.…”

Section: Adding Observationally Motivated Selection Functions and Errorsmentioning

confidence: 98%

Non-parametric spherical Jeans mass estimation with B-splines

Rehemtulla

Valluri

Vasiliev

2022

Monthly Notices of the Royal Astronomical Society

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Spherical Jeans modeling is widely used to estimate mass profiles of systems from star clusters to galactic stellar haloes to clusters of galaxies. It derives the cumulative mass profile, M( < r), from kinematics of tracers of the potential under the assumptions of spherical symmetry and dynamical equilibrium. We consider the application of Jeans modeling to mapping the dark matter distribution in the outer reaches of the Milky Way using field halo stars. We present a novel non-parametric routine for solving the spherical Jeans equation by fitting B-splines to the velocity and density profiles of halo stars. While most implementations assume parametric forms for these profiles, B-splines provide non-parametric fitting curves with analytical derivatives. Our routine recovers the mass profiles of equilibrium systems with flattened haloes or a stellar disc and bulge excellently ($\lesssim 10{{\ \rm per\ cent}}$ error at most radii). Tests with non-equilibrium, Milky Way-like galaxies from the Latte suite of FIRE-2 simulations perform quite well ($\lesssim 15{{\ \rm per\ cent}}$ error for r ≲ 100 kpc). We also create observationally motivated datasets for the Latte suite by imposing selection functions and errors on phase space coordinates characteristic of Gaia and the DESI Milky Way Survey. The resulting imprecise and incomplete data require us to introduce an MCMC-based subroutine to obtain deconvolved density and velocity dispersion profiles from the tracer population. With these observational effects taken into account, the accuracy of the Jeans mass estimate remains at the level 20 per cent or better.

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Section: Adding Observationally Motivated Selection Functions and Errorsmentioning

confidence: 98%

Non-parametric spherical Jeans mass estimation with B-splines

Rehemtulla

Valluri

Vasiliev

2022

Monthly Notices of the Royal Astronomical Society

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“…Gaia Collaboration et al 2018b;Antoja et al 2020;Gaia Collaboration et al 2021d), the Galactic potential (e.g. Crosta et al 2020;Cunningham et al 2020;Hattori et al 2020), and even the Hubble constant (e.g. Breuval et al 2020;Riess et al 2021;Baumgardt & Vasiliev 2021) are constantly increasing thanks to Gaia.…”

Section: Introductionmentioning

confidence: 99%

Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18

Anders

Khalatyan

Chiappini

et al. 2019

A&A

299

312

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Combining the precise parallaxes and optical photometry delivered by Gaia's second data release (Gaia DR2) with the photometric catalogues of Pan-STARRS1, 2MASS, and AllWISE, we derived Bayesian stellar parameters, distances, and extinctions for 265 million of the 285 million objects brighter than G = 18. Because of the wide wavelength range used, our results substantially improve the accuracy and precision of previous extinction and effective temperature estimates. After cleaning our results for both unreliable input and output data, we retain 137 million stars, for which we achieve a median precision of 5% in distance, 0.20 mag in Vband extinction, and 245 K in effective temperature for G ≤ 14, degrading towards fainter magnitudes (12%, 0.20 mag, and 245 K at G = 16; 16%, 0.23 mag, and 260 K at G = 17, respectively). We find a very good agreement with the asteroseismic surface gravities and distances of 7000 stars in the Kepler, K2-C3, and K2-C6 fields, with stellar parameters from the APOGEE survey, and with distances to star clusters. Our results are available through the ADQL query interface of the Gaia mirror at the Leibniz-Institut für Astrophysik Potsdam (gaia.aip.de) and as binary tables at data.aip.de. As a first application, we provide distanceand extinction-corrected colour-magnitude diagrams, extinction maps as a function of distance, and extensive density maps. These demonstrate the potential of our value-added dataset for mapping the three-dimensional structure of our Galaxy. In particular, we see a clear manifestation of the Galactic bar in the stellar density distributions, an observation that can almost be considered direct imaging of the Galactic bar.

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“…The mass distribution in different components of the Galaxy is of great importance to studies of the composition, history, and current dynamical properties of the Galaxy (e.g., Bland-Hawthorn & Gerhard 2016). Stellar streams in the halo have been extensively used to constrain the potential and the density distribution of the Galactic halo (e.g., Malhan & Ibata 2019;Hattori et al 2020;Reino et al 2020). Recent work has shown that the tidal tails of Hyades are likely sensitive to the exact prescription for the Galactic potential and the presence of GMCs (Jerabkova et al 2021).…”

Section: The Impact Of Gmcsmentioning

confidence: 99%

Stellar Streams in the Galactic Disk: Predicted Lifetimes and Their Utility in Measuring the Galactic Potential

Kamdar,

Conroy,

Ting

2021

Preprint

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In this paper we present a holistic view of the detection, characterization, and origin of stellar streams in the disk of a simulated Milky Way-like galaxy. The star-by-star simulation of the Galaxy evolves stars born in clusters in a realistic galactic potential that includes spiral arms, a bar, and giant molecular clouds over 5 Gyr. We first devise a new hybrid method to detect stellar streams that combines phase space density information along with the action-angle space spanned by stars in our simulation. We find that streams' progenitor star clusters and associations are all preferentially higher-mass (> 1000 M ) and young (< 1 Gyr). Our stream-finding method predicts that we might be able to find anywhere from 1 to 10 streams with 6D Gaia DR2 data in the solar neighborhood alone. The simulation suggests that streams are sensitive to the initial dynamical state of clusters, accumulated energy gain from encounters with giant molecular clouds (GMCs), and present-day actions. We investigate what we can learn about the Galactic potential by studying the feasiblity of rewinding stellar streams back to their origin. Even with perfect information about the non-axisymmetric components (spiral arms, bar) of the galactic potential, the stochastic GMC population makes backwards integration impossible beyond one or two disk orbital times. Streams are also sensitive to the properties of the bar, but fairly insensitive to the properties of the non-transient two-armed spiral in our simulation. Finally we predict that around 10 to 30 stellar streams should be detectable with Gaia's 10-year end-of-mission data. There are many more stellar streams waiting to be discovered in the Galactic disk, and they could hold clues about the history of the Galaxy for the past Gyr.

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Action-based distribution function modelling for constraining the shape of the Galactic dark matter halo

Cited by 14 publications

References 80 publications

Non-parametric spherical Jeans mass estimation with B-splines

Non-parametric spherical Jeans mass estimation with B-splines

Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18

Stellar Streams in the Galactic Disk: Predicted Lifetimes and Their Utility in Measuring the Galactic Potential

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