GBT18B-370

Characterizing the Main Beam Efficiency and Error Beam of the Argus Receiver

Abstract

The Dense Extragalactic GBT+Argus Survey (DEGAS; AGBT17B-151) is a GBT Large Program to map 36 nearby galaxies in four molecular gas tracers (HCN, HCO+, 13CO, C18O) ranging from 90GHz to 110GHz. Interpreting the data from this survey requires knowledge of the main beam efficiency and how the error beam of the Argus receiver couples to extended sources. Although some measurements of these parameters were taken during Argus commissioning, there has been no comprehensive measurement of these quantities, particularly at frequencies greater than 86.5GHz.

Characterizing main beam efficiency and error beam requires observations of sources of different angular sizes at the frequencies of interest. Here we propose to observe Mars and Jupiter with the ARGUS receiver at 90GHz, 110GHz, and 115GHz. These observations will allow us to measure the main beam efficiency as well as characterize the error beam on size scales slightly larger than the beam. These observations will complement similar observations that we have already obtained on the full Moon and 0319+4130 (the brightest quasar in the millimeter sky).

Although this campaign is in support of DEGAS, these data will yield information that are generally useful to Argus observers at common observing frequencies.

Investigators

Name	Institution
Amanda Kepley *	National Radio Astronomy Observatory
Dave Frayer	Green Bank Observatory
Andy Harris	Maryland, University of
Jialu Li	Maryland, University of
Erik Rosolowsky	British Columbia at Okanagan, University of ; Alberta, University of

* indicates the PI