Understanding and explaining observed variability in microwave amplification by stimulated emission of radiation (maser) sources in NGC 6334 I

Peter Jairos Banda; Geoffrey Okeng'o; G. C. Macleod

Peter Jairos Banda Department of Physics, University of Nairobi
Geoffrey Okeng'o Department of Physics, University of Nairobi
G. C. Macleod Hartebeesthoek Radio Astronomy Observatory, Johannesburg - South Africa

Keywords: Maser, Star-formation, Periodic variation, Velocity, Local standard of rest

Abstract

An active star forming region NGC 6334I has continued to undergo variations in the velocity and flux intensity of the 1665 MHz OH maser transition. We report the findings of the periodic variation observed in the velocity of the 1665 MHz OH maser for observations that started in October 2011 to December 2016 using the 26 m Hartebeeshoek Observatory radio telescope. Two velocity channels -10.6 kms^-1 and -10.2 kms^-1 in the Left Circular Polarization showed evidence of periodic variation. The period of variation was found to be equal to 366.01 ± 3.33 and 365.89 ± 1.28 days, respectively. The cause of the periodic variation was the uncorrected velocity local standard of rest for maser sources which are far away from NGC 6334I.