Open Access. Powered by Scholars. Published by Universities.^{®}

Articles **1** - **2** of ** 2**

## Full-Text Articles in Physics

A Protostellar Jet Model For The Water Masers In W49n, Mordecai-Mark Mac Low, Moshe Elitzur, James M. Stone, Arieh Königl

#### A Protostellar Jet Model For The Water Masers In W49n, Mordecai-Mark Mac Low, Moshe Elitzur, James M. Stone, Arieh Königl

*Physics and Astronomy Faculty Publications*

Observations by Gwinn, Moran, & Reid of the proper motions of water masers in W49N show that they have elongated distribution expanding from a common center. Features with high space velocity only occur far from the center, while low-velocity features occur at all distances. We propose that these observations can be interpreted in terms of a shell of shocked molecular gas that is driven by the expanding cocoon of a high-velocity protostellar jet. We present three-dimensional numerical simulations in support of this interpretation and argue that this source provides a unique oppurtunity for a detailed study of jet-driven cocoons.

On The Theory Of Astronomical Masers In Three Dimensions, Moshe Elitzur

#### On The Theory Of Astronomical Masers In Three Dimensions, Moshe Elitzur

*Physics and Astronomy Faculty Publications*

In the standard theory of three-dimensional astronomical masers, the radiation field is described as if the source were comprised of a collection of linear masers. To leading order, the standard theory is shown to provide the correct description of three-dimensional masers and its results remain intact, but only within a frequency core whose half-width is χ_{s}Δν_{D}, where Δν_{D }is the Doppler width and χ_{s} is a dimensionless parameter. For any given geometry, χ_{s} is ~1*θ*_{sat}, where *θ*_{sat} is the beaming angle of a maser with that geometry that has just saturated ...