The Milky Way rotation curve revisited

¹ Aix Marseille Univ., CNRS, LAM, Laboratoire d’Astrophysique de Marseille, Marseille, France
e-mail: delphine.russeil@lam.fr
² Istituto Nazionale di Astrofisica – IAPS, via Fosso del Cavaliere 100, 00133 Roma, Italy
³ Observatoire Astronomique de Strasbourg, Université de Strasbourg, CNRS, UMR 7550, 11 rue de l’Université, 67000 Strasbourg, France

Received: 1 February 2017
Accepted: 11 April 2017

Abstract

The Herschel survey of the Galactic Plane (Hi-GAL) is a continuum Galactic plane survey in five wavebands at 70, 160, 250, 350 and 500 μm. From such images, about 150 000 sources have been extracted for which the distance determination is a challenge. In this context the velocity of these sources has been determined thanks to a large number of molecular data cubes. But to convert the velocity to kinematic distance, one needs to adopt a rotation curve for our Galaxy. For three different samples of tracers, we test different analytical forms. We find that the power-law expression, θ(R)/θ₀ = 1.022 (R/R₀)^0.0803 with R₀, θ₀ = 8.34 kpc, 240 km s^-1 is a good and easily manipulated expression for the distance determination process.