Corrections for the Lutz-Kelker Bias for Galactic Masers
  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.
