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Meier, David L.

Publications and source records attributed to Meier, David L..

21 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

VLBI observations at 2.3 GHz of the compact galaxy 1934-638

VLBI observations of the strong radio source 1934-638 show it to be a binary with a component separation of 42.0 + or - 0.2 mas, a position angle of 90.5 + or - 1 deg, and component sizes of about 2.5 mas. The results imply the presence of an additional elongated component aligned with, and between, the compact double components. The sources's almost equal compact double structure, peaked spectrum, low variability, small polarization, and particle-dominated radio lobes suggests that it belongs to the class of symmetric compact double sources identified by Phillips and Mutel (1980, 1981, 1982).

Tzioumis, Anastasios K.↗
NASA NTRS1989

Radio structure at 8.4 GHz in Sagittarius A, the compact radio source at the Galactic center

VLBI observations of the compact, nonthermal radio source at the Galactic center show it to be elongated at 8.4 GHz along a position angle of 82 + or - 6 deg. The source has an axial ratio of 0.53 + or - 0.10 with a major axis of 17.4 + or - 0.5 mas. Examination of VLA maps of the Galactic center region indicate no obvious alignment with this smaller-scale elongation of the nuclear region, nor is the nuclear position angle aligned with the axis of Galactic rotation. Comparison with the size measured at frequencies from 1 to 22 GHz shows that the size follows very closely the lambda-squared dependence expected from interstellar scattering. The alongated nature of the source implies either that the scattering medium is anisotropic or that some remnant of the intrinsic structure remains visible through the scattering medium.

Jauncey, David L.↗