EXCESS LINE BROADENING IN VARIOUS OBJECTS - A CASE FOR WEAK MAGNETIC EFFECTS

I present updated compilations of both observational data and theoreti cal predictions concerning excess line width and sizes in astrophysica l bodies. After removing two well-known broadening mechanisms (thermal width and width due to large scale motions such as expansion), I anal yse statistically the excess line width W-excess. The excess line widt h shows a changing behavior with object size R, of the form W-excess s imilar to R(q). Taking all objects together, I find that q = 0.55 with s.d. = 0.05. This result extends previous studies to cover 5 decades in sizes, from 0.01 pc up to 1000 pc. Taking only objects with R < 1 p c, I find that q = 0.7 with s.d. = 0.1, while taking only objects with R > 1 pc gives q = 0.5 with s.d. = 0.1; thus a steeper (not flatter) value of q at small R may be possible. Previous claims to derive a law for objects of sizes R > 1 kpc are discussed, in relation to the prob lem of removing obvious large scale motions from the observed line wid th. Thus several models with predicted q values between 0 and 1 can be eliminated, and the remaining ones could allow weak magnetic effects on the line widths.