The vertical force in the solar neighbourhood using red clump stars in TGAS and RAVE

Hagen, Jorrit H. J.; Helmi, Amina

doi:10.1051/0004-6361/201832903

Cited by 47 publications

(59 citation statements)

References 57 publications

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“…In ref. [62], the authors derived ρ DM, using red clump stars from TGAS (Tycho-Gaia Astrometric Solution) cross-matched with RAVE DR5 observations. The volume studied to obtain ρ DM, covers |z| ∼ 0.6-1.5 kpc and a Galactocentric radius of |R − R | < 0.5 kpc.…”

Section: Studies Based On Local Observationsmentioning

confidence: 99%

Dark matter local density determination based on recent observations

Salas

2020

J. Phys.: Conf. Ser.

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The local density of dark matter is an important quantity. On the one hand, its value is needed for dark matter direct detection searches. On the other hand, a precise and robust determination of the local dark matter density would help us learn about the shape of the dark matter halo of our Galaxy, which plays an important role in dark matter indirect detection searches, as well as in many studies in astrophysics and cosmology. There are different methods available to determine the local dark matter density. Among them, it is common to study either the vertical kinematics of a selected group of tracers or the rotation curve of the Milky Way. Recent estimates of the local dark matter density have used the precise observations conducted by the ESA/Gaia mission. However, in spite of the quality of the data released by Gaia's observations, different analyses of the local dark matter density produce dissimilar results. After a brief review of the most common methods to estimate the local density of dark matter, here we argue about different explanations for the discrepancies in the results of recent analyses. We finish by presenting new approaches that have been proposed in the literature and could help us improve our knowledge of this important quantity.

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Section: Studies Based On Local Observationsmentioning

confidence: 99%

Dark matter local density determination based on recent observations

Salas

2020

J. Phys.: Conf. Ser.

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“…The advent of the Gaia space mission (Gaia Collaboration 2016) with its successive data releases, has led to a few new analyses (e.g. Hagen & Helmi 2018;Widmark & Monari 2019;Widmark 2019;Buch et al 2019;Nitschai et al 2020). For these new samples, the main sources of error were no longer statistical limitations or measurement accuracy, but systematic biases and errors related to the approximate modelling and to the underlying assumptions.…”

Section: Introductionmentioning

confidence: 99%

Kinematics and dynamics of Gaia red clump stars

Salomon

Bienaymé

Reylé

et al. 2020

A&A

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In this study, we analyse the kinematics and dynamics of a homogeneous sample of red clump stars, selected from the second Gaia data release catalogue in the direction of the Galactic poles, at five different positions in the plane. The level of completeness of the sample at heights between 0.6 and 3.5 kpc was asserted through a comparison with the 2 Micron All Sky Survey catalogue. We show that both the density distribution and velocity dispersion are significantly more perturbed in the north than in the south in all analysed regions of our Galactic neighbourhoods. We provide a detailed assessment of these north-south asymmetries at large heights, which can provide useful constraints for models of the interaction of the Galactic disc with external perturbers. We proceeded to evaluate how such asymmetries could affect determinations of the dynamical matter density under equilibrium assumptions. We find that a Jeans analysis delivers relatively similar vertical forces and integrated dynamical surface densities at large heights above the plane in both hemispheres. At these heights, the densities of stars and gas are very low and the surface density is largely dominated by dark matter (DM), which allows us to estimate, separately in the north and in the south, the local dark matter density derived under equilibrium assumptions. In the presence of vertical perturbations, such values should be considered as an upper limit. This Jeans analysis yields values of the local dark matter density above 2 kpc, namely, ρDM ∼ 0.013 M⊙ pc−3 (∼0.509 GeV cm−3) in the perturbed northern hemisphere and ρDM ∼ 0.010 M⊙ pc−3 (∼0.374 GeV cm−3) in the much less perturbed south. As a comparison, we determine the local dark matter density by fitting a global phase-space distribution to the data. We end up with a value in the range of ρDM ∼ 0.011−0.014 M⊙ pc−3, which is in global agreement with the Jeans analysis. These results call for the further development of non-equilibrium methods with the aim of obtaining a more precise estimate for the dynamical matter density in the Galactic disc.

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“…This is subject to a ≈ 10% uncertainty due to imprecise knowledge of the DM density (Hagen & Helmi 2018 Over a period of T = 10 years, the maximum DMinduced deviation is ≈ Ftyp T 2 /2 = 0.22 mm. Given that the ephemerides of Saturn are accurate to ≈ 30 metres (Viswanathan et al 2017), it is unlikely that the motion of Saturn would be noticeably affected by the Solar DM wake.…”

Section: Methods and Resultsmentioning

confidence: 99%

“…Thus, the total DM-induced displacement of Saturn is only affected a few percent by m > 1 harmonics in Φw. This is much smaller than uncertainties from other parameters like the ≈ 10% error in the local DM density (Hagen & Helmi 2018). Therefore, it is currently not very important to consider these higher harmonics.…”

Section: Vertical Motionmentioning

confidence: 97%

Effect of the Solar dark matter wake on planets

Banik

Kroupa

2019

Monthly Notices of the Royal Astronomical Society

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The Galaxy is conventionally thought to be surrounded by a massive dark matter (DM) halo. As the Sun goes through this halo, it excites a DM wake behind it. This local asymmetry in the DM distribution would gravitationally affect the motions of Solar System planets, potentially allowing the DM wake to be detected or ruled out. Hernandez (2019) recently calculated that the DM-induced perturbation to Saturn's position is 252 metres net of the effect on the Sun. No such anomaly is seen in Saturn's motion despite very accurate tracking of the Cassini spacecraft, which orbited Saturn for >13 years.Here, we revisit the calculation of how much Saturn would deviate from Keplerian motion if we fix its position and velocity at some particular time. The DM wake induces a nearly resonant perturbation whose amplitude grows almost linearly with time. We show that the Hernandez (2019) result applies only for an observing duration comparable to the ≈ 250 million year period of the Sun's orbit around the Galaxy. Over a 100 year period, the perturbation to Saturn's orbit amounts to <1 cm, which is quite consistent with existing observations. Even smaller perturbations are expected for the terrestrial planets.

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The vertical force in the solar neighbourhood using red clump stars in TGAS and RAVE

Cited by 47 publications

References 57 publications

Dark matter local density determination based on recent observations

Dark matter local density determination based on recent observations

Kinematics and dynamics of Gaia red clump stars

Effect of the Solar dark matter wake on planets

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