CO (1-0) and CO (5-4) observations of the most distant known radio galaxy at z=5.2

Using the Australia Telescope Compact Array, we have detected CO (1-0) and CO (5-4) from TN J0924-2201 at z = 5.2, the most distant radio galaxy known to date. This is the second highest redshift detection of CO published so far. The CO (1-0) line emission is 250-400 km s(-1) wide with a peak flux density of 520 +/- 115 muJy beam(-1), while the CO (5-4) line emission is 200-300 km s(-1) wide with a peak flux density of 7.8 +/- 2.7 mJy beam(-1). Both transitions are spatially unresolved, but there is marginal evidence for spatial offsets between the CO and the host galaxy; the CO (1-0) is located 28 +/- 11 kpc (4.5 +/- 1.7) north of the radio galaxy, while 28 the CO (5-4) is located 18 +/- 8 kpc (2.8 +/- 1.2) south of the radio galaxy. Higher spatial resolution observations are required to determine the reality of these offsets. Our result is the second detection of CO in a high-redshift galaxy without preselection based on a massive dust content.