Exceptional AGN-driven turbulence inhibits star formation in the 3C 326N radio galaxy

Guillard, P.; Boulanger, F.; Lehnert, M. D.; Forêts, G. Pineau des; Combes, F.; Falgarone, É.; Bernard─Salas, J.

doi:10.1051/0004-6361/201423612

Cited by 60 publications

(68 citation statements)

References 115 publications

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“…NGC 1266 (Alatalo et al 2015). However, the injection of large amounts of energy in the gas disk may have a similar effect as increasing the turbulence of the gas, a process that is also thought to inhibit star formation (see the case of 3C 326, Guillard et al 2015).…”

Section: Discussionmentioning

confidence: 99%

The fast molecular outflow in the Seyfert galaxy IC 5063 as seen by ALMA

Morganti

Oosterloo

Oonk

et al. 2015

A&A

216

269

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We use high-resolution (0.5 arcsec) CO(2−1) observations performed with the Atacama Large Millimetre/submillimetre Array to trace the kinematics of the molecular gas in the Seyfert 2 galaxy IC 5063. The data reveal that the kinematics of the gas is very complex. A fast outflow of molecular gas extends along the entire radio jet (∼1 kpc), with the highest outflow velocities about 0.5 kpc from the nucleus, at the location of the brighter hot spot in the western lobe. The ALMA data show that a massive, fast outflow with velocities up to 650 km s −1 of cold molecular gas is present, in addition to the outflow detected earlier in warm H 2 , H i and ionized gas. All phases of the gas outflow show similar kinematics. IC 5063 appears to be one of the best examples of the multi-phase nature of AGN-driven outflows. Both the central AGN and the radio jet could energetically drive the outflow, however, the characteristics of the outflowing gas point to the radio jet being the main driver. This is an important result because IC 5063, although one of the most powerful Seyfert galaxies, is a relatively weak radio source (P 1.4 GHz = 3 × 10 23 W Hz −1 ). All the observed characteristics can be described by a scenario of a radio plasma jet expanding into a clumpy medium, interacting directly with the clouds and inflating a cocoon that drives a lateral outflow into the interstellar medium. This model is consistent with results obtained by recent simulations. A stronger, direct interaction between the jet and a gas cloud is present at the location of the brighter western lobe. This interaction may also be responsible for the asymmetry in the radio brightness of the two lobes. Even assuming the most conservative values for the conversion factor CO-to-H 2 , we find that the mass of the outflowing gas is between 1.9 and 4.8 × 10 7 M , of which between 0.5 and 1.3 × 10 7 M is associated with the fast outflow at the location of the western lobe. These amounts are much larger than those of the outflow of warm gas (molecular and ionized) and somewhat larger than of the H i outflow. This suggests that most of the observed cold molecular outflow is due to fast cooling after being shocked. This gas is the end product of the cooling process, although some of it could be the result of only partly dissociated clouds. Our CO observations demonstrate that fast outflows of substantial masses of molecular gas can be driven by relativistic jets, although in the case of IC 5063 the outflows are not fast enough to remove significant amounts of gas from the galaxy and the effects are limited to the central ∼0.5 kpc from the centre.

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Section: Discussionmentioning

confidence: 99%

The fast molecular outflow in the Seyfert galaxy IC 5063 as seen by ALMA

Morganti

Oosterloo

Oonk

et al. 2015

A&A

216

269

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“…Far-IR molecular observations can provide key and unique insight into the outflow phenomenon: (i) the strength and optical depth of the far-IR continuum generates P-Cygni line profiles in some lines, unambiguously indicating the presence of outflowing gas, discarding other alternatives such as high turbulence or non-circular rotation motions (e.g., Guillard et al 2015;Díaz-Santos et al 2016); (ii) blueshifted absorption can be traced to low velocities, probing low-velocity outflows that may be missed from pure emission lines due to confusion with the line core; (iii) despite the relatively poor spatial resolution of far-IR telescopes, multi-transition observations including high-lying transitions, provide a robust means to quantify the main outflow parameters (mass outflow rate, momentum flux, etc).…”

Section: Introductionmentioning

confidence: 99%

Molecular Outflows in Local ULIRGs: Energetics from Multitransition OH Analysis

González-Alfonso

Fischer

Spoon

et al. 2017

ApJ

143

204

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We report on the energetics of molecular outflows in 14 local Ultraluminous Infrared Galaxies (ULIRGs) that show unambiguous outflow signatures (P-Cygni profiles or high-velocity absorption wings) in the far-infrared lines of OH measured with the Herschel/PACS spectrometer. All sample galaxies are gas-rich mergers at various stages of the merging process. Detection of both ground-state (at 119 and 79 µm) and one or more radiatively-excited (at 65 and 84 µm) lines allows us to model the nuclear gas ( 300 pc) as well as the more extended components using spherically symmetric radiative transfer models. Reliable models and the corresponding energetics are found in 12 of the 14 sources. The highest molecular outflow velocities are found in buried sources, in which slower but massive expansion of the nuclear gas is also observed. With the exception of a few outliers, the outflows have momentum fluxes of (2 − 5) × L IR /c and mechanical luminosities of (0.1 − 0.3)% of L IR . The moderate momentum boosts in these sources ( 3) suggest that the outflows are mostly momentum-driven by the combined effects of AGN and nuclear starbursts, as a result of radiation pressure, winds, and supernovae remnants. In some sources (∼ 20%), however, powerful (10 10.5−11 L ⊙ ) AGN feedback and (partially) energy-conserving phases are required, with momentum boosts in the range 3 − 20. These outflows appear to be stochastic, strong-AGN feedback events that occur throughout the merging process. In a few sources, the outflow activity in the innermost regions has subsided in the last ∼ 1 Myr. While OH traces the molecular outflows at sub-kpc scales, comparison of the masses traced by OH with those previously inferred from tracers of more extended outflowing gas suggests that most mass is loaded (with loading factors ofṀ /SFR = 1 − 10) from the central galactic cores (a few × 100 pc), qualitatively consistent with an ongoing inside-out quenching of star formation. Outflow depletion timescales are < 10 8 yr, shorter than the gas consumption timescales by factors of 1.1 − 15, and are anti-correlated with the AGN luminosity.

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“…Recently, interferometric molecular gas observations have shown that the star formation within some quenched objects is suppressed, with inefficiencies of factors of 20-70 (Aalto et al 2016;Alatalo et al 2015aAlatalo et al , 2015cGuillard et al 2015;Lanz et al 2016;Salomé et al 2016), leading to the possibility that star-formationsuppressed molecular reservoirs are a common part of galaxy transformation. However,a larger sample of galaxies must be studied to determine whether this occurs only in rare and energetic objects.…”

Section: Introductionmentioning

confidence: 99%