Shocks in dense clouds

Chlorine in Dense Interstellar Clouds: the Abundance

We report the first detection of a chlorine-bearing molecular species in the interstellar medium via emission from the J = 1----> 0 transition of HCl at 625.9 GHz toward OMC-1. The relative strengths, widths, and velocities of the resolved hyperfine components are consistent with moderate optical depth emission originating from dense, quiescent molecular cloud material (VLsR = 9 km s1). The ove...

Observations of in Dense Molecular Clouds

has been detected using infrared absorption spectroscopy along the lines of sight to six infrared 3 sources in dense molecular clouds : AFGL 2136, W33A, Mon R2 IRS 3, AFGL 961E, AFGL 2591, and AFGL 490. Upper limits to the column densities of are reported for an additional nine sources. The 3 column densities of CO toward Mon R2 IRS 3 and AFGL 961E have been determined from observations of the ...

H3+ in dense and diffuse clouds.

Interstellar H3+ has been detected in dense as well as diffuse clouds using three 3.7 microns infrared spectral lines of the nu 2 fundamental band. Column densities of H3+ from (1.7-5.5) x 10(14) cm-2 have been measured in dense clouds in absorption against the infrared continua of the deeply embedded young stellar objects GL2136, W33A, MonR2 IRS 3, GL961E, and GL2591. Strong and broad H3+ abso...

Elemental nitrogen partitioning in dense interstellar clouds.

Many chemical models of dense interstellar clouds predict that the majority of gas-phase elemental nitrogen should be present as N(2), with an abundance approximately five orders of magnitude less than that of hydrogen. As a homonuclear diatomic molecule, N(2) is difficult to detect spectroscopically through infrared or millimeter-wavelength transitions. Therefore, its abundance is often inferr...

The Chemistry of Transient Dense Cores in Interstellar Clouds