GBT26A-545

Where is the Diffuse HI in NGC 5238?

Abstract

NGC5238 is an intriguing and cosmologically important low-mass galaxy. The low surface brightness stellar structure indicates past tidal interactions, making NGC5238 a paradigm example of the process of hierarchical structure formation taking place at low stellar masses. Our previous multi-configuration VLA campaign has revealed unusual physical properties: the HI component of NGC5238 is significantly smaller than the stellar component, and the total HI mass is significantly less than the stellar mass. The recent FASHI measurement of NGC5238 suggests that its total HI flux integral is significantly larger than the values found in our VLA datasets and also in previous single-dish measurements. A high S/N GBT HI spectrum will allow investigation of this discrepancy. The primary science goal is very simple: to enable a detailed comparison of the global HI profiles derived from the GBT data, the FAST data, and our deep multi-configuration VLA data. A novel additional goal is to incorporate single-dish radio astrophysics into the curriculum at Macalester College; the data from this program will enable unique experiential learning for undergraduate students.

Investigators

Name	Institution
GBT Operator	Green Bank Observatory
John Cannon *	Macalester College

* indicates the PI