GBT24A-319

A Search for H2CO in Molecular Clouds Entrained in the Nuclear Wind

Abstract

Several hundred clouds are now known to be entrained in the nuclear wind of the Milky Way, accelerated to outflow velocities of several hundreds of km/s. These clouds were discovered primarily through their 21cm HI emission, although a few are also known through UV absorption lines. Remarkably, several have been detected in CO emission implying that they have a significant molecular compoinent. The CO emission has a distinctly different morphology from the HI and there is evidence of cloud evolution with distance from the Galactic center. The column densities of HI and H2 imply that the clouds are far from equilibrium, and are in the process of being dissociated. They most likely have a unique chemistry. We propose to search for H2CO absorption in several of these clouds to answer the question of whether the molecular content is traced entirely by CO, or whether there may be a more widespread molecular component. In the 6cm line of H2CO the GBT has the sensitivity and angular resolution to answer this simple question.

Investigators

Name	Institution
Jay Lockman *	Green Bank Observatory
Enrico Di Teodoro	Firenze, Università degli Studi di
Naomi McClure-Griffiths	Australian National University
Karlie Noon	Australian National University
Mark Hemeon-Heyer	Massachusetts at Amherst, University of
Toney Minter	Green Bank Observatory

* indicates the PI