Corrections for the Lutz-Kelker Bias for Galactic Masers

TL;DR

This study applies Lutz-Kelker bias corrections to Galactic maser data, refining the Galactic rotation curve parameters and spiral pattern characteristics based on high-precision measurements.

Contribution

It introduces bias corrections to maser distance measurements and refines Galactic rotation and spiral pattern parameters using these corrected data.

Findings

Lutz-Kelker bias significantly affects the angular velocity .

Refined Galactic rotation parameters with high precision.

Determined spiral pattern pitch angle and Sun's phase in the spiral wave.

Abstract

Based on published data, we have collected information about Galactic maser sources with measured distances. In particular, 44 Galactic maser sources located in star-forming regions have trigonometric parallaxes, proper motions, and radial velocities. In addition, ten more radio sources with incomplete information are known, but their parallaxes have been measured with a high accuracy. For all 54 sources, we have calculated the corrections for the well-known Lutz-Kelker bias. Based on a sample of 44 sources, we have refined the parameters of the Galactic rotation curve. Thus, at R_0=8 kpc, the peculiar velocity components for the Sun are (Uo,Vo,Wo)=(7.5,17.6,8.4)+\-(1.2,1.2,1.2) km s^-1 and the angular velocity components are \omega_0=-28.7+\-0.5 km s^-1 kpc^-1, \omega'_0=+4.17+\-0.10 km s^-1 kpc^-2, and \omega''_0=-0.87+\-0.06 km s^-1 kpc^-3. The corresponding Oort constants are A=16.7+\-0.6 km s^-1 kpc^-1 and B=-12.0+\-1.0 km s^-1 kpc^-1; the circular rotation velocity of the solar neighborhood around the Galactic center is V_0 = 230+\-16 km s^-1. We have found that the corrections for the Lutz-Kelker bias affect the determination of the angular velocity \omega_0 most strongly; their effect on the remaining parameters is statistically insignificant. Within the model of a two-armed spiral pattern, we have determined the pattern pitch angle i=-6.5^\circ and the phase of the Sun in the spiral wave \chi_0=150^\circ.