We present Karl G. Jansky Very Large Array (VLA) K-band (19 GHz) observations of the redshifted CO(1-0) line emission toward the radio galaxy TN J0924$-$2201 at $z=5.2$, which is one of the most distant CO-detected radio galaxies. With the angular resolution of $\sim2''$, the CO(1-0) line emission is resolved into three clumps, within $\pm500$ km\,s$^{ -1}$ relative to its redshift, where is determined by Ly$\alpha$. We find that they locate off-center and 12-33 kpc away from the center of the host galaxy, which has counterparts in $HST$ $i$-band, $Spitzer$/IRAC and ALMA Band-6 (230 GHz; 1.3 mm). With the ALMA detection, we estimate $L_{ \rm IR}$ and SFR of the host galaxy to be $(9.3\pm1.7)\times10^{ 11} L_{ \odot}$ and $110\pm20$ $M_{ \odot}\,\rm yr^{ -1}$, respectively. We also derive the $3\sigma$ upper limit of $M_{ \rm H_{ 2}}<1.3\times10^{ 10}$ $M_{ \odot}$ at the host galaxy. The detected CO(1-0) line luminosities of three clumps, $L'_{ \rm CO(1-0)}$ = (3.2-4.7)$\times10^{ 10}$ $\rm\,K\,km\,s^{ -1}pc^{ 2}$, indicate the presence of three massive molecular gas reservoirs with $M_{ \rm H_{ 2}}$ = (2.5-3.7)$\times10^{ 10}$ $M_{ \odot}$, by assuming the CO-to-H$_{ 2}$ conversion factor $\alpha_{ \rm CO} = 0.8$ $M_{ \rm \odot}\rm\,(K\,km\,s^{ -1}pc^{ 2})^{ -1}$, although the star formation rate (SFR) is not elevated because of the non-detection of ALMA 1.3 mm continuum (SFR $<$ 40 $M_\odot$ yr$^{ -1}$). From the host galaxy, the nearest molecular gas clump labeled as clump A, is apparently aligning with the radio jet axis, showing the radio-CO alignment. The possible origin of these three clumps around TN J0924$-$2201 can be interpreted as merger, jet-induced metal enrichment and outflow.
Categories: astro-ph.GA