The Line-of-Sight Distribution of Water in SgrB2
/ Authors
/ Abstract
The SgrB2 cloud is one of the most massive star forming regions in our Galaxy. It has many unique characteristics, among them an exceptional chemistry. Several species (FeO, [21]; NH2, [20]; HF, [15]; C3, [7]) have, in spite of searches elsewhere, been detected only toward this source. One possible explanation for this enigmatic chemistry is the existence of a layer of hot gas, which is thought to be produced by a shock. Since this layer has the same velocity as the ambient gas in SgrB2, it has been proven difficult to assess its importance for the chemistry of many species, with a few exceptions. In particular its importance for the water chemistry has been a matter of recent debate ([3]; [17]). While its temperature and density are well known (cf. [9]), its column density and width have remained elusive. In this work (illustrated in detail in [5]) we have been able to determine its importance for water chemistry and give constraints for column density and spatial width, by modeling the HDO and H2 18O emission and absorption.