Abstract. We present results of a comprehensive multi-frequency study of the radio galaxy B3 J2330+3927. The 1. 9 wide radio source, consisting of 3 components, is bracketed by 2 objects in our Keck K-band image. Optical and near-IR Keck spectroscopy of these two objects yield z = 3.087 ± 0.004. The brightest (K = 18.8) object has a standard type II AGN spectrum, and is the most likely location of the AGN, which implies a one-sided jet radio morphology. Deep 113 GHz observations with the IRAM Plateau de Bure Interferometer reveal CO J = 4−3 emission, which peaks at the position of the AGN. The CO line is offset by 500 km s −1 from the systemic redshift of the AGN, but corresponds very closely to the velocity shift of an associated H I absorber seen in Lyα. This strongly suggests that both originate from the same gas reservoir surrounding the AGN host galaxy. Simultaneous 230 GHz interferometer observations find a ∼3× lower integrated flux density when compared to single dish 250 GHz observations with MAMBO at the IRAM 30 m telescope. This can be interpreted as spatially resolved thermal dust emission at scales of 0. 5 to 6 . Finally, we present a τ < 1.3% limit to the H I 21 cm absorption against the radio source, which represents the seventh nondetection out of 8 z > 2 radio galaxies observed to date with the WSRT. We present mass estimates for the atomic, neutral, and ionized hydrogen, and for the dust, ranging from M(H I) = 2 × 10 7 M derived from the associated H I absorber in Lyα up to M(H 2 ) = 7 × 10 10 M derived from the CO emission. This indicates that the host galaxy is surrounded by a massive reservoir of gas and dust. The K-band companion objects may be concentrations within this reservoir, which will eventually merge with the central galaxy hosting the AGN.
Abstract. We present new radio images obtained with the Australia Telescope Compact Array (ATCA) and the Very Large Array (VLA) for a group of 14 galaxies belonging to the 2-Jy sample of radio sources. The new images improve the data already available on these objects and, in general, the database that we are building up on the sample. They will also be used for follow-up work where radio-optical comparison will be done.We briefly discuss the core dominance parameter (R) for the objects for which the new data have given new information and, in particular, for broad line radio galaxies (BLRG). One of the BLRG does not show a core, even at 3 cm, and this is at variance with the general tendency of BLRG to have relatively strong cores. The depolarization is also discussed for a group of small double-lobed radio galaxies.
We report the discovery of a new 21-cm H I absorption system using commissioning data from the Boolardy Engineering Test Array of the Australian Square Kilometre Array Pathfinder (ASKAP). Using the 711.5 -1015.5 MHz band of ASKAP we were able to conduct a blind search for the 21-cm line in a continuous redshift range between z = 0.4 and 1.0, which has, until now, remained largely unexplored. The absorption line is detected at z = 0.44 towards the GHz-peaked spectrum radio source PKS B1740−517 and demonstrates ASKAP's excellent capability for performing a future wide-field survey for H I absorption at these redshifts. Optical spectroscopy and imaging using the Gemini-South telescope indicates that the H I gas is intrinsic to the host galaxy of the radio source. The narrow [O III] emission lines show clear double-peaked structure, indicating either large-scale outflow or rotation of the ionized gas. Archival data from the XMM-Newton satellite exhibit an absorbed X-ray spectrum that is consistent with a high column density obscuring medium around the active galactic nucleus. The H I absorption profile is complex, with four distinct components ranging in width from 5 to 300 km s −1 and fractional depths from 0.2 to 20 per cent. In addition to systemic H I gas, in a circumnuclear disc or ring structure aligned with the radio jet, we find evidence for a possible broad outflow of neutral gas moving at a radial velocity of v ∼ 300 km s −1 . We infer that the expanding young radio source (t age ≈ 2500 yr) is cocooned within a dense medium and may be driving circumnuclear neutral gas in an outflow of ∼ 1 M yr −1 .
Young radio AGN are pivotal for our understanding of many of the still-debated aspects of AGN feedback. In this paper we present a study of the interstellar medium (ISM) in the compact, peaked-spectrum radio galaxy PKS B1934-63 using X-shooter observations. Most of the warm ionized gas resides within a circum-nuclear disk with a radius of about 200 pc that is likely to constitute the gas reservoir from which the central black hole feeds. On the other hand, we find a biconical outflow of warm ionized gas with an estimated radius of 59 ± 12 pc. This matches the radial extent of the radio source and suggests that the outflow is jet driven. Thanks to the superior wavelength coverage of the data, we can estimate the density of the warm ionized gas using the trans-auroral line technique, and we find that the outflowing gas has remarkably high density, up to log n e (cm −3 ) 5.5. The estimated mass outflow rate is low (Ṁ =10 −3 -10 −1 M yr −1 ), and the AGN feedback operates at relatively low efficiency (Ė/L bol ∼ 10 −4 -10 −3 %). In addition, optical and near-IR line ratios show that the expansion of the radio source drives fast shocks (with velocities v s 500 km s −1 ) that ionize and accelerate the outflowing gas. At odds with the properties of other compact, peaked-spectrum radio sources hosting warm ionized gas outflows, we do not find signs of kinematically disturbed or outflowing gas in phases colder than the warm ionized gas. We argue that this is due to the young age of our source and thus to the recent nature of the AGN-ISM interaction, and suggest that cold gas forms within the outflowing material and the shock-ionized outflowing gas of PKS B1934-63 did not have enough time to cool down and accumulate in a colder phase. This scenario is also supported by the multi-phase outflows of other compact and young radio sources in the literature.
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