view Abstract Citations (23) References (26) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Galactic Structures Associated with Extreme Scattering Events in the Radio Light Curves of NRAO 140, 0954+658, and 2352+495 Fiedler, R. ; Pauls, T. ; Johnston, K. J. ; Dennison, B. Abstract Of the nine quasars whose radio light curves contain suspected extreme scattering events (ESEs), we find that the lines of sight toward three of them (NRAO 140, 0954+658, and 2352+495) pass through the edges of clearly identifiable Galactic structures seen at IR wavelengths and in 21 cm continuum emission. These structures are possible sites for enhanced turbulence in the electron column density distribution which, through diffractive or refractive propagation effects, may be responsible for the unusual flux density variations we denote as an ESE. Of the remaining six sources whose light curves display an ESE, four (0133+476, 300+470, 1749+096, and 1821 + 107) appear near the edges of 100 micron IR clumps in the Galactic foreground and two (1502 + 106 and 1611 + 343) are 1^deg^-2^deg^ from the nearest clump. We suggest that the shell-like object, observed in projection against NRAO 140, may be a very old nova remnant. Publication: The Astrophysical Journal Pub Date: August 1994 DOI: 10.1086/174433 Bibcode: 1994ApJ...430..595F Keywords: Electron Density (Concentration); Galactic Structure; Light Curve; Plasma Turbulence; Quasars; Radio Emission; Astronomical Models; Continuum Modeling; Cosmology; Infrared Radiation; Radio Sources (Astronomy); Supernova Remnants; Astrophysics; GALAXIES: QUASARS: GENERAL; ISM: STRUCTURE; RADIO CONTINUUM: GALAXIES; TURBULENCE full text sources ADS | data products SIMBAD (19) NED (10)