ATCA detections of massive molecular gas reservoirs in dusty, high-z radio galaxies

Abstract

Observations using the 7 mm receiver system on the Australia Telescope Compact Array have revealed large reservoirs of molecular gas in two high-redshift radio galaxies: HATLAS J090426.9+015448 (z = 2.37) and HATLAS J140930.4+003803 (z = 2.04). Optically the targets are very faint, and spectroscopy classifies them as narrow-line radio galaxies. In addition to harbouring an active galactic nucleus the targets share many characteristics of sub-mm galaxies. Far-infrared data from Herschel-ATLAS suggest high levels of dust (>10^9 M_solar) and a correspondingly large amount of obscured star formation (~1000 M_solar / yr). The molecular gas is traced via the J = 1-0 transition of 12CO, its luminosity implying total H_2 masses of (1.7 +/- 0.3) x 10^11 and (9.5 +/- 2.4) x 10^10 (alpha_CO/0.8) M_solar in HATLAS J090426.9+015448 and HATLAS J140930.4+003803 respectively. Both galaxies exhibit molecular line emission over a broad (~1000 km/s) velocity range, and feature double-peaked profiles. We interpret this as evidence of either a large rotating disk or an on-going merger. Gas depletion timescales are ~100 Myr. The 1.4 GHz radio luminosities of our targets place them close to the break in the luminosity function. As such they represent `typical' z > 2 radio sources, responsible for the bulk of the energy emitted at radio wavelengths from accretion-powered sources at high redshift, and yet they rank amongst the most massive systems in terms of molecular gas and dust content. We also detect 115 GHz rest-frame continuum emission, indicating a very steep high-radio-frequency spectrum, possibly classifying the targets as compact steep spectrum objects.

arXiv comment11 pages, 5 figures, accepted for publication in MNRAS

References in corpus (82)

• Galactic Stellar and Substellar Initial Mass Function
• Star Formation in Galaxies Along the Hubble Sequence
• Planck 2013 results. XVI. Cosmological parameters
• The CO-to-H2 Conversion Factor
• Rotating Nuclear Rings and Extreme Starbursts in Ultraluminous Galaxies
• Cool Gas in High Redshift Galaxies
• Galaxy and Mass Assembly (GAMA): survey diagnostics and core data release
• Very High Gas Fractions and Extended Gas Reservoirs in z=1.5 Disk Galaxies
• Spectral Energy Distributions of Hard X-ray selected AGNs in the XMDS Survey
• Molecular Gas at High Redshift
• Submillimeter Galaxies at z~2: Evidence for Major Mergers & Constraints on Lifetimes, IMF and CO-H2 Conversion Factor
• The Herschel ATLAS
• The SCUBA Local Universe Galaxy Survey I: First Measurements of the Submillimetre Luminosity and Dust Mass Functions
• High-resolution Millimeter Imaging of Submillimeter Galaxies
• The 1000 Brightest HIPASS Galaxies: HI Properties
• A survey of molecular gas in luminous sub-millimetre galaxies
• Distant Radio Galaxies and their Environments
• Star Formation and Gas Kinematics of Quasar Host Galaxies at z~6: New insights from ALMA
• A General Model for the CO-H2 Conversion Factor in Galaxies with Applications to the Star Formation Law
• The Australia Telescope Compact Array Broadband Backend (CABB)
• Evidence for powerful AGN winds at high redshift: Dynamics of galactic outflows in radio galaxies during the "Quasar Era"
• A comparative HST imaging study of the host galaxies of radio-quiet quasars, radio-loud quasars and radio galaxies: Paper I
• Tracing the molecular gas in distant submillimetre galaxies via CO(1-0) imaging with the EVLA
• The metallicity dependence of the CO {\rightarrow} H_2 conversion factor in z>1 star forming galaxies
• The far-infrared/radio correlation as probed by Herschel
• Galaxy Clusters around radio-loud AGN at 1.3 < z < 3.2 as seen by Spitzer
• Cosmic evolution of submillimeter galaxies and their contribution to stellar mass assembly
• Interferometric Observations of Powerful CO Emission from the three Submillimeter Galaxies at z=2.30, 2.51 and 3.35
• Spatially Resolved Millimeter Interferometry of SMMJ02399-0136: a Very Massive Galaxy at z=2.8
• Evidence for a clumpy, rotating gas disk in a submillimeter galaxy at z=4
• The far-infrared/radio correlation and radio spectral index of galaxies in the SFR-M* plane up to z 2
• Herschel-ATLAS: a binary HyLIRG pinpointing a cluster of starbursting proto-ellipticals
• The Far-Infrared--Radio Correlation at High Redshifts: Physical Considerations and Prospects for the Square Kilometer Array
• LOFAR/H-ATLAS: A deep low-frequency survey of the Herschel-ATLAS North Galactic Pole field
• Star formation and the interstellar medium in z>6 UV-luminous Lyman-break galaxies
• Extended Cold Molecular Gas Reservoirs in z~3.4 Submillimeter Galaxies
• CO(4-3) and dust emission in two powerful high-z radio galaxies, and CO lines at high redshifts
• A sample of 6C radio sources designed to find objects at redshift > 4: III --- imaging and the radio galaxy K-z relation
• A first sample of faint radio sources with virtually complete redshifts: I. Infrared images, the Hubble diagram, and the alignment effect
• Blind detections of CO J = 1--0 in 11 H-ATLAS galaxies at z = 2.1--3.5 with the GBT/Zpectrometer
• Quasars Probing Quasars III: New Clues to Feedback, Quenching, and the Physics of Massive Galaxy Formation
• The local radio-galaxy population at 20 GHz
• Gas-rich mergers and feedback are ubiqitous amongst starbursting radio galaxies, as revealed by JVLA, IRAM PdBI and Herschel
• The optical morphologies of the 2Jy sample of radio galaxies: evidence for galaxy interactions
• Gas, dust and stars in the SCUBA galaxy, SMM J02399-0136: the EVLA reveals a colossal galactic nursery
• Why z > 1 radio-loud galaxies are commonly located in proto-clusters
• The Baryonic Halos of Elliptical Galaxies: Radial Distribution of Globular Clusters and Diffuse Hot Gas
• A Molecular Line Scan in the Hubble Deep Field North: Constraints on the CO Luminosity Function and the Cosmic H2 Density
• Herschel-ATLAS: The far-infrared--radio correlation at z<0.5
• A search for distant radio galaxies from SUMSS and NVSS: III. radio spectral energy distributions and the z-alpha correlation
• Detection of Two Massive CO Systems in 4C 41.17 at z = 3.8
• Evolution of the Far-Infrared-Radio Correlation and Infrared SEDs of Massive Galaxies over z = 0 - 2
• Prediction of the Cosmic Evolution of the CO-Luminosity Functions
• CO(1-0) survey of high-z radio galaxies: alignment of molecular halo gas with distant radio sources
• A mature galaxy cluster at z=1.58 around the radio galaxy 7C1753+6311
• NGC6240: Merger-Induced Star Formation & Gas Dynamics
• Herschel-ATLAS: Properties of dusty massive galaxies at low and high redshifts
• Formation of a Quasar Host Galaxy through a Wet Merger 1.4 Billion Years after the Big Bang
• Detection of molecular gas in a distant submillimetre galaxy at z=4.76 with ATCA
• Herschel-ATLAS/GAMA: a difference between star-formation rates in strong-line and weak-line radio galaxies
• No Evidence for Evolution in the Far-Infrared-Radio Correlation out to z ~ 2 in the eCDFS
• CO(1-0) & CO(5-4) observations of the most distant known radio galaxy at z=5.2
• Isothermal dust models of Herschel-ATLAS galaxies
• Detection of CO J=1-0 in the z=3.79 radio galaxy 4C60.07
• The environments of high redshift radio galaxies and quasars: probes of protoclusters
• CO (J=3-2) Emission in the Radio Galaxy 53W002 at z=2.394
• CO line emission in the halo of a radio galaxy at z=2.6
• Probing the absorbing haloes around two high-redshift radio galaxies with VLT-UVES
• A 325-MHz GMRT survey of the Herschel-ATLAS/GAMA fields
• Molecular Gas in the z=1.2 Ultraluminous Merger GOODS J123634.53+621241.3
• The faint source population at 15.7 GHz - I. The radio properties
• HI in the proto-cluster environment at z>2: absorbing haloes and the Lyman alpha forest
• CO observations of high-z radio galaxies MRC 2104-242 and MRC 0943-242: spectral-line performance of the Compact Array Broadband Backend
• A CO-rich merger shaping a powerful and hyper-luminous infrared radio galaxy at z=2: the Dragonfly Galaxy
• Multi-Frequency Optical-Depth Maps and the Case for Free-Free Absorption in Two Compact Symmetric Radio Sources: the CSO candidate J1324+4048 and the CSO J0029+3457
• The preferentially magnified active nucleus in IRAS F10214+4724 - II. Spatially resolved cold molecular gas
• 10C continued: a deeper radio survey at 15.7 GHz
• Strongly lensed neutral hydrogen emission: detection predictions with current and future radio interferometers
• New Constraints on the Molecular Gas in the Prototypical HyLIRGs BRI1202-0725 & BRI1335-0417
• The radio spectral energy distribution of infrared-faint radio sources
• Ground-state 12CO emission and a resolved jet at 115 GHz (rest-frame) in the radio loud quasar 3C318
• A Bayesian blind survey for cold molecular gas in the Universe

Cited by in corpus (1)

• Galaxy Evolution in the Radio Band: The Role of Starforming Galaxies and Active Galactic Nuclei