nai

Project Summary

Irvine and colleagues at the University of Massachusetts have been using a unique new broadband radio receiver to measure the spectra of external galaxies in the 3mm wavelength region, and hence to study the chemistry of their interstellar gas. The so-called Redshift Search Receiver allows the simultaneous observation of essentially the entire 3mm spectrum of a galaxy, and hence to measure the molecular emissions in this band. Including all the 10 galaxies observed, we detected 20 spectral lines from 14 different atomic and molecular species. There are interesting differences in the chemistry of these objects, e.g., in the relative strength of emission lines from HCN, HNC, HCO+, CH3OH, 13CO , CS and N2H+ (a proxy for N2). The receiver is ultimately intended for use on the Large Millimeter Telescope; however, until the LMT is completed, the receiver has been tested at the Five College Radio Astronomy Observatory’s 14-meter telescope, operated by the University of Massachusetts Amherst.