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A Highly Flexible Spectrometer

Spectroscopy

Spectroscopy is the study of spectral lines and is widely applied in astronomy. Spectral lines of radiation emitted by gaseous matter in space reveal considerable information its properties and surroundings.

Each gas, be it atomic hydrogen or carbon monoxide, emits its own distinct set of spectral lines. These characteristic spectra enable astronomers to identify the different gases and to measure their temperatures, densities, and motions. Using this information, researchers can infer what takes place in the depths of space.

The BIMA Spectrometer

To obtain spectra, researchers employ spectrometers which become a part of the telescope. Radiation collected by the telescope passes through the spectrometer yielding spectral lines. In the case of the BIMA array, its spectrometer breaks apart the millimeter radiation it collects, revealing the spectral lines of a great number of molecules.

The molecular gas which resides in giant molecular clouds is relatively "cold" compared to surrounding gases. Designed to analyze the emissions of this cooler gas, the BIMA array's spectrometer is highly flexible. It can isolate simulataneously the spectral lines of many different gas molecules, at both high and low spectroscopic resolution. Since astronomers can obtain all this data during a single run, they need fewer, shorter observing sessions.

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NCSA.Last modified 11/12/95