Ground-state 12CO emission and a resolved jet at 115 GHz (rest-frame) in the radio loud quasar 3C318

Abstract

An analysis of 44 GHz VLA observations of the z = 1.574 radio-loud quasar 3C318 has revealed emission from the redshifted J = 1 - 0 transition of the CO molecule and spatially resolved the 6.3 kpc radio jet associated with the quasar at 115 GHz rest-frame. The continuum-subtracted line emitter is spatially offset from the quasar nucleus by 0.33" (2.82 kpc in projection). This spatial offset has a significance of >8-sigma and, together with a previously published -400 km/s velocity offset measured in the J = 2 - 1 CO line relative to the systemic redshift of the quasar, rules out a circumnuclear starburst or molecular gas ring and suggests that the quasar host galaxy is either undergoing a major merger with a gas-rich galaxy or is otherwise a highly disrupted system. If the merger scenario is correct then the event may be in its early stages, acting as the trigger for both the young radio jets in the quasar and a starburst in the merging galaxy. The total molecular gas mass in the spatially offset line emitter as measured from the ground-state CO line M_H2 = 3.7 (+/-0.4) x 10^10 (alpha_CO/0.8) M_solar. Assuming that the line-emitter can be modelled as a rotating disk, an inclination-dependent upper limit is derived for its dynamical mass M_dyn sin^2(i) < 3.2 x 10^9 M_solar, suggesting that for M_H2 to remain less than M_dyn the inclination angle must be i < 16 degrees. The far infrared and CO luminosities of 246 extragalactic systems are collated from the literature for comparison. The high molecular gas content of 3C318 is consistent with that of the general population of high redshift quasars and sub-millimetre galaxies.

10 pages, 4 figures, 2 tables (additional table to appear online as supplementary material), accepted for publication in MNRAS

References in corpus (13)

• CO(1-0) in z >/~ 4 Quasar Host Galaxies: No Evidence for Extended Molecular Gas Reservoirs
• Testing the Evolutionary Link Between Submillimetre Galaxies and Quasars: CO Observations of QSOs at z~2
• The rapid assembly of an elliptical galaxy of 400 billion solar masses at a redshift of 2.3
• Dense Molecular Gas and the Role of Star Formation in the Host Galaxies of Quasi-Stellar Objects
• Molecular gas in nearby low-luminosity QSO host galaxies
• Molecular gas in QSO host galaxies at z>5
• VLA imaging of 12CO J=1-0 and free-free emission in lensed submillimetre galaxies
• Properties of the molecular gas in a starbursting QSO at z=1.83 in the COSMOS field
• Molecular gas observations of the reddened quasar 3C 318
• Molecular gas in type 2 quasars at z~0.2-0.3
• The preferentially magnified active nucleus in IRAS F10214+4724 - II. Spatially resolved cold molecular gas
• High Sensitivity Array Observations of the $z=4.4$ QSO BRI 1335-0417
• GPS & CSS radio sources and space-VLBI

Cited by in corpus (5)

• Compact steep-spectrum and peaked-spectrum radio sources
• The Discovery of Gas-Rich, Dusty Starbursts in Luminous Reddened Quasars at $z\sim 2.5$ with ALMA
• Multi-phase outflows in high redshift quasar host galaxies
• The far-infrared emission of the radio-loud quasar 3C318
• ATCA detections of massive molecular gas reservoirs in dusty, high-z radio galaxies