Limits on the local dark matter density

Details Limits on the local dark matter density Limits on the local dark matter density

2011-05-31

arxiv.org/abs/1105.6339v2

Astronomy and Astrophysics

Astrophysics

Galaxy Astrophysics

25 pages, 21 figures; accepted for publication in MNRAS

Scientific paper

10.1111/j.1365-2966.2011.19206.x

We revisit systematics in determining the local dark matter density (rho_dm) from the vertical motion of stars in the Solar Neighbourhood. Using a simulation of a Milky Way-like galaxy, we determine the data-quality required to detect the dark matter density at its expected local value. We introduce a new method for recovering rho_dm that uses moments of the Jeans equations, combined with a Monte Carlo Markov Chain technique to marginalise over the unknown parameters. Given sufficiently good data, we show that our method can recover the correct local dark matter density even in the face of disc inhomogeneities, non-isothermal tracers and a non-separable distribution function. We illustrate the power of our technique by applying it to Hipparcos data [Holmberg & Flynn 2000,2004]. We first make the assumption that the A and F star tracer populations are isothermal. This recovers rho_dm=0.003^{+0.009}_{-0.007}Msun/pc^3 (with 90 per cent confidence), consistent with previous determinations. However, the vertical dispersion profile of these tracers is poorly known. If we assume instead a non-isothermal profile similar to the blue disc stars from SDSS DR-7 [Abazajian et al. 2009] measured by Bond et al. (2009), we obtain a fit with a very similar chi^2 value, but with rho_dm=0.033^{+0.008}_{-0.009}Msun/pc^3 (with 90 per cent confidence). This highlights that it is vital to measure the vertical dispersion profile of the tracers to recover an unbiased estimate of the local dark matter density.

Affiliated with

Also associated with

No associations

Rating

Limits on the local dark matter density does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Limits on the local dark matter density, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Limits on the local dark matter density will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-339116