Publications of the Astronomical Society of the Pacific

Plavec, Miroslav

doi: 10.1086/128996pmid: N/A

Turner, B. E.

doi: 10.1086/128997pmid: N/A

Of the seven molecules presently detected at radio wavelengths in the interstellar medium, OH and H2O display sectacular emission properties attributed to maser action. The OH masers all into three distinct classes herein described, each of which is anomalously excited by a different pumping mechanism. Far IR radiative pumping is applied to recent observations of anomalous OH emission in dust clouds. The excitation of OH by the collisional dissociation of water vapor is described next, and is shown to explain recent observations of microwave emission from excited states of OH. It also explains why the type of OH emission that it produces (Class I) is observed to occur in the same regions as anomalous H2O emission. A pumping mechanism for the H20 is also described which is expected to operate in any regions in which Class I OH emission occurs.

McNamara, D. H.; Langford, W. R.

doi: 10.1086/128998pmid: N/A

doi: 10.1086/128999pmid: N/A

Krienke, O. K.; Hodge, P. W.

doi: 10.1088/1538-3873/82/489/1032pmid: N/A

Wright, K. O.

doi: 10.1086/129000pmid: N/A

Noonan, Thomas W.

doi: 10.1086/129001pmid: N/A

An assumption regarding the randomness of the selection of galaxies in a redshift catalog is used to by-pass the need for a specific luminosity function in arriving at the mean cosmic density. Application of the method to the Humason-Mayall-Sandage catalog, with the use of published mass-luminosity ratios, ives a mean density of (11 l 6) X 10-31 gm cm-3. A by-product of the ana ysis is the denial of the rinciple that outlying galaxies near a cluster which show the same average reds ift as the cluster are cluster members.

Sastry, Gummuluru N.

doi: 10.1086/129002pmid: N/A

Branch, David; Peery, Benjamin F.

doi: 10.1086/129003pmid: N/A

Bond, Howard E.

doi: 10.1086/129004pmid: N/A