(Pseudo) radiative pumprate of OH 1612MHz masers is defined for a sample of 44 OH/IR sources (infrared sources with OH 1612MHz maser), irrespective of the real maser pumping mechanisms. The correlation between the (pseudo) maser pumprates and the evolutionary status of the maser sources reveals that the radiative pumprates of stellar OH masers are nearly fixed, which agrees with the theoretical...

We performed VLA observations of the 22 GHz H2O maser emission in the merging galaxy NGC 6240, which hosts the well-known double active nuclei. In a previous paper, we reported on the first solid detection of the H2O maser emission in 2001. After two abortive attempts due to the weakness and probable variability of the emission, the maser was detected with the VLA in June 2002. The emission is ...

The class II methanol maser source G9.62+0.20E undergoes periodic flares at both 6.7 and 12.2 GHz. The flare starting in 2001 October was observed at seven epochs over three months using the VLBA at 12.2 GHz. High angular resolution images (beam size ∼ 1.7 x 0.6 mas) were obtained, enabling us to observe changes in 16 individual maser components. It was found that while existing maser spots inc...

The OH 1667 MHz maser in the circumstellar shell around the Mira variable U Her has been observed with the NRAO Very Long Baseline Array (VLBA) at 6 epochs, spread over 4 years. Using phase referencing techniques the position of the most blue-shifted maser spot was monitored with respect to two extra-galactic radio sources. The absolute radio positions of the maser can be compared with the stel...

The present paper describes the interaction of the maser with the soliton, finally deriving the fundamental ball lightning (BL) equation for the linear heat diffusion case. This equation is a rough first approximation based on many drastic simplifications. It assumes stationarity and neglects the field emission of carriers caused by the maser. Our calculations prove for the first time that the ...

Aims. Recently, substantial flaring in the 6.7 GHz methanol maser line has been observed toward the high-mass young stellar object (YSO) S255 NIRS 3, where an accretion burst was also detected in the IR. Our goal is to study the change in the properties of the 6.7 GHz masers between the preand outburst phases, and investigate the connection between the maser and the accretion burst. Methods. Wi...

A polarized maser is assumed to operate in an anisotropic medium with natural modes polarized differently to the maser. It is shown that when the spatial growth rate and the generalized Faraday rotation rate are comparable, the polarization of the growing radiation is different from those of the maser and medium. In particular, for a lineary polarized maser operating in a medium with linearly p...

Based on the space MSX observation in bands A(8μm), C(12μm), D(15μm) and E(21μm), and the ground SiO maser observation of evolved stars by the Nobeyama 45-m telescope in the v=1 and v=2 J=1-0 transitions, the relation between SiO maser emission and mid-IR continuum radiation is analyzed. The relation between SiO maser emission and the IR radiation in the MSX bands A, C, D and E is all clearly c...

A new class of OH (1720 MHz) masers unaccompanied by main-line transitions have recently been discovered (Frail, Goss and Slysh 1994). These masers lie at the interface between supernova remnants (SNRs) interacting with molecular clouds. We discuss three new aspects of SN masers found in the direction toward the Galactic center: (i) the detection of a new –130 kms OH (1720 MHz) maser in the sou...