Atmospheric transmission at submillimetre wavelengths from Mauna Kea

Abstract

The submillimetre atmospheric transmission spectrum above Mauna Kea has been measured at a resolution of 0.005 cm−1 (150 MHz) with a Fourier transform spectrometer at the James Clerk Maxwell Telescope, using the Sun as a source. Column abundances of O2, H2O and O3 determined from these spectra are found to be in excellent agreement with independent measurements. The derived column abundances have been used as inputs to the atmospheric spectral modelling program fascod. The synthetic transmission spectrum is found to be in excellent agreement with the measured spectrum, and provides a template for submillimetre observations from the JCMT.

Fourier transform spectroscopy of the submillimetre continuum emission from hot molecular cores

“…For all observations, the gain was set to G = 10 4 . J s (ν) is the true spectrum of the source, J sky (ν) is the true spectrum of the atmosphere, J amb (ν) is the power received from ambient temperature surfaces of the telescope, and J ′(ν) is the power received through the second port of the FTS, which is differenced in the interferometric measurement (Naylor et al 2000). The first term therefore represents the power received from the astronomical source itself through the atmosphere and instrument, the second term represents the power received from the atmosphere and the third term represents the power received from the surfaces of the telescope, which are at ambient temperature.…”

The study of THz wave propagation feature in atmosphere

“…But the origin of aerosol can be divided into: Mainland (Haze L), sea (Haze M) and high stereotype (Haze H) [12] 2)Junge spectrum…”

Mach-Zehnder Fourier transform spectrometer for astronomical spectroscopy at submillimeter wavelengths

“…Interferograms of low quality are deleted at this stage; those affected by cosmic rays can generally be recovered by the interactive removal of the associated noise spikes. The next step is to apply standard FTS analysis techniques 6 . Since the optical elements in the spectrometer and detector produce negligible dispersion over the narrow spectral ranges of interest, in most cases a linear phase correction function is computed (by weighting phase values obtained from a short, doublesided interferogram by the amplitude of the corresponding spectral point) and convolved with the edited interferogram, to produce a phase-corrected interferogram.…”

“…In more recent years a dual-polarization bolometer detector system 5 has been developed for use with the polarizing FTS. Results from these programs include: measurements of the atmospheric transmission throughout the submillimeter spectral region 6 , the search for HCN, NH3 and PH3 in the troposphere of Jupiter 7 , the detection of CO in the troposphere of Neptune 8 , the detection of high-n HI Rydberg transitions in the submillimeter spectrum of the sun 9,10 and measurements of line emission from the Orion molecular cloud 11 . For reference, the atmospheric transmission above Mauna Kea for 0.5 mm precipitable water vapour, corresponding to relatively dry conditions, is shown in figure 1.…”