[CI] 370 µm and CO (7-6) and (6-5) Observations of ULIRGs with ZEUS

¹ Cornell University, Ithaca, NY 14853, USA
² Goddard Space Flight Center

Corresponding author: tn46@cornell.edu

Abstract

We have begun a survey of the [CI] 370 μm fine structure line and of mid-J CO line emission from ULIRGs and starburst galaxies using our grating spectrometer ZEUS on the CSO. Here we present observations from six ULIRGs: Mrk 231, Zw 049.057, NGC 6240, Arp 299, Arp 220, and IRAS 17208. The CO (6-5)/FIR ratio in ULIRGs appears to be lower for ULIRGs than for LIRGs. Comparing the CO SEDs of the ULIRGs shows the necessity of obtaining CO rotational transitions up to at least J = 7 to properly constrain LVG models.