The Milky Way's Circular Velocity Curve and Its Constraint on the Galactic Mass with RR Lyrae Stars

Ablimit, Iminhaji; Zhao, Gang

doi:10.3847/1538-4357/aa83b2

Cited by 23 publications

(14 citation statements)

References 45 publications

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“…Basically, spectroscopic observations can be used to measure line-of-sight velocities with respect to the Sun. If we know the solar motion 2) , Heliocentric distances and velocities can be used to obtain radial velocities with respect to the Galactic center. When proper motions are not available and hence tangential velocities are difficult to be robustly inferred 3) , Eqn.…”

Section: The High Velocity Tail Distribution Of Halo Starsmentioning

confidence: 99%

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The mass of our Milky Way

Wang¹,

Han²,

Cautun³

et al. 2020

Sci. China Phys. Mech. Astron.

112

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We perform an extensive review of the numerous studies and methods used to determine the total mass of the Milky Way. We group the various studies into seven broad classes according to their modeling approaches. The classes include: i) estimating Galactic escape velocity using high velocity objects; ii) measuring the rotation curve through terminal and circular velocities; iii) modeling halo stars, globular clusters and satellite galaxies with the Spherical Jeans equation and iv) with phase-space distribution functions; v) simulating and modeling the dynamics of stellar streams and their progenitors; vi) modeling the motion of the Milky Way, M31 and other distant satellites under the framework of Local Group timing argument; and vii) measurements made by linking the brightest Galactic satellites to their counterparts in simulations. For each class of methods, we introduce their theoretical and observational background, the method itself, the sample of available tracer objects, model assumptions, uncertainties, limits and the corresponding measurements that have been achieved in the past. Both the measured total masses within the radial range probed by tracer objects and the extrapolated virial masses are discussed and quoted. We also discuss the role of modern numerical simulations in terms of helping to validate model assumptions, understanding systematic uncertainties and calibrating the measurements. While measurements in the last two decades show a factor of two scatters, recent measurements using Gaia DR2 data are approaching a higher precision. We end with a detailed discussion of future developments in the field, especially as the size and quality of the observational data will increase tremendously with current and future surveys. In such cases, the systematic uncertainties will be dominant and thus will necessitate a much more rigorous testing and characterization of the various mass determination methods.

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Section: The High Velocity Tail Distribution Of Halo Starsmentioning

confidence: 99%

“…Their best-fit potential model led to the virial mass of M 200 = 0.85 +0.07 −0.08 × 10 12 M . In 2017, Ablimit and Zhao [2] adopted 860 ab-type RR Lyrae stars in the Galactic halo to look at the rotation velocities out to ∼50 kpc using the SJE. Their sample of stars 000000-16…”

Section: Inferring Mass and Anisotropy From Datamentioning

confidence: 99%

The mass of our Milky Way

Wang¹,

Han²,

Cautun³

et al. 2020

Sci. China Phys. Mech. Astron.

112

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“…In the past decades, tremendous efforts have been made to map and understand the Milky Way including its assembly history and structures, and studies to date (e.g., Searle & Zinn 1978;Flynn et al 1996;Helmi et al 1999;Flynn et al 2006;Nusser 2009;Bovy et al 2012;Ness et al 2013;Wegg & Gerhard 2013;Bensby et al 2013;Rix & Bovy 2013;Reid et al 2014;Bird & Flynn 2015;Gaia Collaboration et al 2016;Bonaca et al 2017;Wang et al 2018;Gallart et al 2019;Koppelman et al 2019;Mackereth & Bovy 2020;Belokurov et al 2020;Ablimit et al 2020;Oman et al 2020;Fragkoudi et al 2020;Bobylev et al 2020;Ferraro et al 2020;Queiroz et al 2020;Rizzuti et al 2021;Widmark et al 2021;de Salas & Widmark 2021) show that revealing the facts of the Milky Way still needs further investigations. Stellar tracers are crucial tools to achieve the goal of studying the Milky Way, such as RR Lyrae variable stars (RRLs) (e.g., Preston 1959;Kinman et al 1966;Oort & Plaut 1975;Saha 1985;Suntzeff et al 1991;Watkins et al 2009;Ablimit & Zhao 2017;Navarro et al 2021;Iorio & Belokurov 2021).…”

Section: Introductionmentioning

confidence: 99%

The Milky Way Revealed by Variable Stars I: Sample Selection of RR Lyrae stars, and Evidence for the Merger History

Ablimit,

Zhao,

Teklimakan

et al. 2021

Preprint

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In order to study the Milky Way, RR Lyrae (RRL) variable stars identified by Gaia, ASAS-SN and ZTF sky survey projects have been analyzed as tracers in this work. Photometric and spectroscopic information of 3417 RRLs including proper motions, radial velocity and metallcity are obtained from observational data of Gaia, LAMOST, GALAH, APOGEE and RAVE. Precise distances of RRLs with typical uncertainties less than 3% are derived by using a recent comprehensive period-luminosity-metallicity relation. Our results from kinematical and chemical analysis provide important clues for the assembly history of the Milky Way, especially for the Gaia-Sausage ancient merger. The kinematical and chemical trends found in this work are consistent with that of recent simulations which indicated that the Gaia-Sausage merger is the dual origin of the Galactic thick disc and halo. As recent similar works have found, the halo RRLs sample in this work contains a subset of radially biased orbits besides a more isotropic component. This higher orbital anisotropy component amounts to β 0.8, and it contributes between 42% and 83% of the halo RRLs at 4 < R(kpc) < 20.

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“…In this paper, we investigate density profiles of the Galactic thick disk and halo by using 1148 RRLab variable stars presented in our previous paper (Ablimit & Zhao 2017, hereafter paper I). We briefly describe our RRL sample and methods in §2.…”

Section: Introductionmentioning

confidence: 99%

The Density Profile and Kinematics of the Milky Way with RR Lyrae Stars

Ablimit

Zhao

2018

ApJ

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Most of known RR Lyraes are type ab RR Lyraes (RRLab), and they are the excellent tool to map the Milky Way and its substructures. We find that 1148 RRLab stars determined by Drake et al.(2013) have been observed by spectroscopic surveys of SDSS and LAMOST. We derived radial velocity dispersion, circular velocity and mass profile from 860 halo tracers in our paper I. Here, we present the stellar densities and radial velocity distributions of thick disk and halo of the Milky Way. The 288 RRLab stars located in the thick disk have the mean metallicity of [Fe/H]= −1.02. Three thick disk tracers have the radial velocity lower than 215 km s −1 . With 860 halo tracers which have a mean metallicity of [Fe/H]= −1.33, we find a double power-law of n(r) ∝ r −2.8 and n(r) ∝ r −4.8 with a break distance of 21 kpc to express the halo stellar density profile. The radial velocity dispersion at 50 kpc is around 78 km s −1 .

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The Milky Way's Circular Velocity Curve and Its Constraint on the Galactic Mass with RR Lyrae Stars

Cited by 23 publications

References 45 publications

The mass of our Milky Way

The mass of our Milky Way

The Milky Way Revealed by Variable Stars I: Sample Selection of RR Lyrae stars, and Evidence for the Merger History

The Density Profile and Kinematics of the Milky Way with RR Lyrae Stars

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