A Dynamical Mass Estimate from the Magellanic Stream

Craig, Peter; Chakrabarti, Sukanya; Baum, Stefi A.; Lewis, Benjamin T.

doi:10.48550/arxiv.2107.09791

Cited by 5 publications

(6 citation statements)

References 56 publications

(124 reference statements)

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“…However, equilibrium methods still assume independence between tracers; the development of methods that can better deal with substructure and nonindependence of tracers (possibly by identification and removal) would be very valuable for reducing systematics in Milky Way mass estimates. Exploring methods for estimating the mass without relying on dynamical tracers would also be worthwhile (see, e.g., Zaritsky & Courtois 2017;Craig et al 2021).…”

Section: Future Prospectsmentioning

confidence: 99%

The Mass of the Milky Way from the H3 Survey

Shen

Eadie

Murray

et al. 2022

ApJ

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The mass of the Milky Way is a critical quantity that, despite decades of research, remains uncertain within a factor of two. Until recently, most studies have used dynamical tracers in the inner regions of the halo, relying on extrapolations to estimate the mass of the Milky Way. In this paper, we extend the hierarchical Bayesian model applied in Eadie & Juri to study the mass distribution of the Milky Way halo; the new model allows for the use of all available 6D phase-space measurements. We use kinematic data of halo stars out to 142 kpc, obtained from the H3 survey and Gaia EDR3, to infer the mass of the Galaxy. Inference is carried out with the No-U-Turn sampler, a fast and scalable extension of Hamiltonian Monte Carlo. We report a median mass enclosed within 100 kpc of M ( < 100 kpc ) = 0.69 − 0.04 + 0.05 × 10 12 M ⊙ (68% Bayesian credible interval), or a virial mass of M 200 = M ( < 216.2 − 7.5 + 7.5 kpc ) = 1.08 − 0.11 + 0.12 × 10 12 M ⊙ , in good agreement with other recent estimates. We analyze our results using posterior predictive checks and find limitations in the model’s ability to describe the data. In particular, we find sensitivity with respect to substructure in the halo, which limits the precision of our mass estimates to ∼15%.

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Section: Future Prospectsmentioning

confidence: 99%

The Mass of the Milky Way from the H3 Survey

Shen

Eadie

Murray

et al. 2022

ApJ

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“…The total mass of our Galaxy is a crucial variable for understanding the results of both astrophysical dark matter measurements and direct detection experiments. Currently uncertain at the factor of ∼ 2 level [e.g., [191][192][193], the Milky Way mass can be determined with percent-level accuracy with future measurements of velocities in stellar streams by wide-field spectroscopic facilities [194]. The velocities of stars in the outer reaches of the Milky Way's dark matter halo, obtained with the same instruments, may also contribute to this measurement.…”

Section: A Key Measurement Opportunitiesmentioning

confidence: 99%

Snowmass2021 Cosmic Frontier White Paper: Observational Facilities to Study Dark Matter

Chakrabarti¹,

Drlica-Wagner²,

Li³

et al. 2022

Preprint

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We present an overview of future observational facilities that will significantly enhance our understanding of the fundamental nature of dark matter. These facilities span a range of observational techniques including optical/near-infrared imaging and spectroscopy, measurements of the cosmic microwave background, pulsar timing, 21-cm observations of neutral hydrogen at high redshift, and the measurement of gravitational waves. Such facilities are a critical component of a multi-pronged experimental program to uncover the nature of dark matter, while often providing complementary measurements of dark energy, neutrino physics, and inflation.

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“…This information is also important for studies that attempt to use Stream properties (mass, length, etc.) to constrain the Milky Way halo density (e.g., Craig et al 2021). 3.…”

Section: The Trailing Magellanic Streammentioning

confidence: 99%

Radiative Turbulent Mixing Layers and the Survival of Magellanic Debris

Bustard

Grönke

2022

ApJ

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The Magellanic Stream is sculpted by its infall through the Milky Way’s circumgalactic medium, but the rates and directions of mass, momentum, and energy exchange through the stream-halo interface are relative unknowns critical for determining the origin and fate of the Stream. Complementary to large-scale simulations of LMC-SMC interactions, we apply new insights derived from idealized, high-resolution cloud-crushing and radiative turbulent mixing layer simulations to the Leading Arm and Trailing Stream. Contrary to classical expectations of fast cloud breakup, we predict that the Leading Arm and much of the Trailing Stream should be surviving infall and even gaining mass due to strong radiative cooling. Provided a sufficiently supersonic tidal swing-out from the Clouds, the present-day Leading Arm could be a series of high-density clumps in the cooling tail behind the progenitor cloud. We back up our analytic framework with a suite of converged wind-tunnel simulations, finding that previous results on cloud survival and mass growth can be extended to high Mach number (  ) flows with a modified drag time t drag ∝ 1 +  and longer growth time. We also simulate the Trailing Stream; we find that the growth time is long (approximately gigayears) compared to the infall time, and approximate Hα emission is low on average (∼ a few milliRayleigh) but can be up to tens of milliRayleigh in bright spots. Our findings also have broader extragalactic implications, e.g., galactic winds, which we discuss.

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A Dynamical Mass Estimate from the Magellanic Stream

Cited by 5 publications

References 56 publications

The Mass of the Milky Way from the H3 Survey

The Mass of the Milky Way from the H3 Survey

Snowmass2021 Cosmic Frontier White Paper: Observational Facilities to Study Dark Matter

Radiative Turbulent Mixing Layers and the Survival of Magellanic Debris

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