Kinematics of the Galaxy from Cepheids with proper motions from the Gaia DR1 catalogue

TL;DR

This study combines Gaia DR1 proper motions with Cepheid data to refine the Galaxy's kinematic parameters, including Solar motion and rotation curve, providing updated values for Galactic dynamics.

Contribution

It introduces a new analysis of Galactic kinematics using Gaia DR1 proper motions combined with Cepheid distances and velocities, improving parameter estimates.

Findings

Solar peculiar velocity components determined: (U,V,W)=(7.90,11.73,7.39) km/s.

Galactic rotation curve parameters estimated: _0=28.84 km/s/kpc, '=-4.05 km/s/kpc^2, ''=0.805 km/s/kpc^3.

Local Standard of Rest velocity V_0=231 km/s.

Abstract

The sample of classic Cepheids with known distances and line-of-sight velocities is supplemented by the proper motions from the Gaia DR1 catalog. From spatial velocities of 260 stars the components of the peculiar Solar velocity: (U,V,W)_\odot=(7.90,11.73,7.39)+/-(0.65,0.77,0.62) km/s, parameters of the Galactic rotation curve: \Omega_0 =28.840+/-.33 km/s/kpc, \Omega'_0=-4.05+/-0.10 km/s/kpc^2, \Omega''_0=0.805+/-0.067 km/s/kpc^3 are obtained. For the adopted Galactocentric Solar distance R_0=8 kpc the linear circular velocity of the Local Standard of Rest is found as V_0=231+/-6 km/s.