in order to clarify the pump process in class ii methanol masers we intend to perform fp-observations of 4 torsional transitions of methanol at 35,39,52,and 63 micron.the lines at 35 and 39 micron are expected to be strong absorption lines,the measurement of which will allow to estimate the column density of the methanol molecules in the upper and lower level of the 12 ghz maser line.we intend to combine the fp-observations of these lines with grating observations of the stretching mode lines at 10 micron. the latter will give information about the total column density of the methanol molecules in the ground vibrational state and about the relative excitation whithin the ground state.the lines at 52 and 63 micron are predicted to be in emission and may even turn out to be iraser lines.if they are observed in emission against a bright background continuum,this would be strong evidence for optical pumping.- to clarify the pump process in some detail is also a contribution to the determination of the physical parameters within the maser region. we have selected three targets -two for each launch date- which are bright enough for fp-observations.both belong to the strongest 12 ghz masers. the targets are w3(oh), ngc 6334 f (autumn only), and cepa (spring only).
Instrument
SWS07
Temporal Coverage
1996-03-04T11:20:23Z/1996-03-04T12:08:31Z
Version
1.0
Mission Description
The Infrared Space Observatory (ISO) was the world's first true orbiting infrared observatory. Equipped with four highly-sophisticated and versatile scientific instruments, it was launched by Ariane in November 1995 and provided astronomers world-wide with a facility of unprecedented sensitivity and capabilities for a detailed exploration of the Universe at infrared wavelengths.
European Space Agency, 1999, Methanol-Masers: Pump Mechanism And Possible Iraser-Lines, 1.0, European Space Agency, https://doi.org/10.5270/esa-v3nexdn
