Energetics of the molecular gas in the H<sub>2</sub>luminous radio galaxy 3C 326: Evidence for negative AGN feedback

Nesvadba, N. P. H.; Boulanger, F.; Salomé, P.; Guillard, P.; Lehnert, M. D.; Ogle, Patrick; Appleton, P. N.; Falgarone, É.; Forêts, G. Pineau des

doi:10.1051/0004-6361/200913333

Cited by 139 publications

(256 citation statements)

References 130 publications

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“…The contribution of the former is important for the (RQ) PlawG, and the latter for the (RL) CoreG ). This explanation is in line with the results of Nesvadba et al (2010) and Ogle et al (2010) for RL AGN, which is consistent with a model of cold gas emission powered by the dissipation of mechanical energy through shocks by radio jets.…”

Section: Molecular Gas and Nuclear Propertiessupporting

confidence: 92%

Molecular gas and nuclear activity in early-type galaxies: any link with radio loudness?

Baldi

Giroletti

Capetti

et al. 2015

A&A

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Aims. We want to study the amount of molecular gas in a sample of nearby early-type galaxies (ETGs) that host low-luminosity active galactic nuclei (AGN). We look for possible differences between the radio-loud (RL) and radio-quiet (RQ) AGN. Methods. We observed the CO(1-0) and CO(2-1) spectral lines with the IRAM 30 m and NRO 45 m telescopes for eight galaxies. They belong to a large sample of 37 local ETGs that host both RQ and RL AGN. We gather data from the literature for the entire sample. Results. We report the new detection of CO(1-0) emission in four galaxies (UGC 0968, UGC 5617, UGC 6946, and UGC 8355) and CO(2-1) emission in two of them (UGC 0968 and UGC 5617). The CO(2-1)/CO(1-0) ratio in these sources is ∼0.7 ± 0.2. Considering both the new observations and the literature, the detection rate of CO in our sample is 55± 9%, with no statistically significant difference between the hosts of RL and RQ AGNs. For all the detected galaxies we converted the CO luminosities into the molecular masses, M H 2 , which range from 10 6.5 to 10 8.5 M , without any statistically significant differences between RL and RQ galaxies. This suggests that the amount of molecular gas does not likely set the radio loudness of the AGN. Furthermore, despite the low statistical significance, the presence of a weak trend between the H 2 mass with various tracers of nuclear activity (mainly [O III] emission line nuclear power) cannot be excluded.

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Section: Molecular Gas and Nuclear Propertiessupporting

confidence: 92%

Molecular gas and nuclear activity in early-type galaxies: any link with radio loudness?

Baldi

Giroletti

Capetti

et al. 2015

A&A

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“…The CO(1−0) line detected with PdBI is weak (1 Jy km s −1 ) and marginally spatially resolved (with a beam size of 2.5 × 2.1 ) (Nesvadba et al 2010). The line seems broad (FWHM = 350 ± 100 km s −1 ), but unfortunately the low signal-to-noise ratio of this detection makes it difficult to infer any detailed information about the kinematics of the bulk molecular gas mass.…”

Section: Introductionmentioning

confidence: 95%

“…This A&A 574, A32 (2015) holes and massive galaxies still have to be elucidated either observationally or theoretically. Of several possibilities, the most energetically favored are: energetic outflows with high entrainment rates driven by the mechanical and radiative energy output of AGN through disk winds, radio jets, and/or radiation pressure (e.g., Fabian 2012;Morganti et al 2013a;McNamara et al 2014, and references therein); cosmic ray pressure and ionization both exciting and energizing the surrounding interstellar medium (ISM; e.g., Sijacki et al 2008;Jubelgas et al 2008;Salem & Bryan 2013); and/or AGN-generated turbulence (e.g., Nesvadba et al 2010;Sani et al 2012;Guillard et al 2012). All of these processes are purported to prevent the collapse and cooling of ISM and/or halo gas thus inhibiting efficient star formation and fueling the supermassive black hole.…”

Section: Introductionmentioning

confidence: 99%

“…The ratio between the mass of warm molecular gas (derived from mid-infrared (MIR) H 2 line observations) and the mass of H 2 derived from CO line emission (assuming a Galactic CO-to-H 2 conversion factor) is about ten times more in 3C 326 1 than in star-forming galaxies (Roussel et al 2007). The kinetic luminosity of the gas and line emission exceed the energy injection rates from star formation and AGN radiation, leaving the mechanical energy and cosmic rays deposited by the radio source the most likely processes heating the gas (Nesvadba et al 2010).…”

Section: Introductionmentioning

confidence: 99%

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

Guillard

Boulanger

Lehnert

et al. 2015

A&A

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We detect bright [Cii]λ158 μm line emission from the radio galaxy 3C 326N at z = 0.09, which shows no sign of ongoing or recent star formation (SFR < 0.07 M yr −1 ) despite having strong H 2 line emission and a substantial amount of molecular gas (2 × 10 9 M , inferred from the modeling of the far-infrared (FIR) dust emission and the CO(1−0) line emission). The [Cii] line is twice as strong as the 0−0S(1) 17 μm H 2 line, and both lines are much in excess of what is expected from UV heating. We combine infrared Spitzer and Herschel photometry and line spectroscopy with gas and dust modeling to infer the physical conditions in the [Cii]-emitting gas. The [Cii] line, like rotational H 2 emission, traces a significant fraction (30 to 50%) of the total molecular gas mass. This gas is warm (70 < T < 100 K) and at moderate densities 700 < n H < 3000 cm [Cii] is similar to the profiles of the near-infrared H 2 lines and the Na D optical absorption lines, and is likely to be shaped by a combination of rotation, outflowing gas, and turbulence. If the line wing is interpreted as an outflow, the mass loss rate would be higher than 20 M yr −1 , and the depletion timescale close to the orbital timescale (≈3 × 10 7 yr). If true, we are observing this object at a very specific and brief time in its evolution, assuming that the disk is not replenished. Although there is evidence of an outflow in this source, we caution that the outflow rates may be overestimated because the stochastic injection of turbulent energy on galactic scales can create short-lived, large velocity increments that contribute to the skewness of the line profile and mimic outflowing gas. The gas physical conditions raise the issue of the heating mechanism of the warm gas, and we show that the dissipation of turbulent energy is the main heating process. Cosmic rays can also contribute to the heating, but cannot be the dominant heating source because it requires an average gas density that is higher than the observational constraints. After subtracting the contribution of the disk rotation, we estimate the turbulent velocity dispersion of the molecular gas to be 120 < σ turb < 330 km s −1 , which corresponds to a turbulent heating rate that is higher than the gas cooling rate computed from the line emission. The dissipation timescale of the turbulent energy (2 × 10 7 −10 8 yrs) is comparable to or larger than the jet lifetime or the dynamical timescale of the outflow, which means that turbulence can be sustained during the quiescent phases when the radio jet is shut off. The strong turbulent support maintains a very high gas scale height (0.3 to 4 kpc) in the disk. The cascade of turbulent energy can inhibit the formation of gravitationally bound structures on all scales, which offers a natural explanation for the lack of ongoing star formation in 3C 326N, despite its having sufficient molecular gas to form stars at a rate of a few solar mass per year. To conclude, the bright [Cii] line indicates that strong AGN jet-driven turbulence may play a key ...

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“…Direct observations show that jets can influence gas many tens of kpc from the centre of the parent host galaxy (e.g. Nesvadba et al 2010Nesvadba et al , 2011Emonts et al 2011). Indeed, the brightest radio structures in radio-loud AGN are often observed on kpc scales and are produced by the coupling of the AGN outflow to its environment (e.g.…”

Section: Introductionmentioning

confidence: 99%

Observational evidence that positive and negative AGN feedback depends on galaxy mass and jet power

Kalfountzou

Stevens

Jarvis

et al. 2017

Monthly Notices of the Royal Astronomical Society

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Several studies support the existence of a link between the AGN and star formation activity. Radio jets have been argued to be an ideal mechanism for direct interaction between the AGN and the host galaxy. A drawback of previous surveys of AGN is that they are fundamentally limited by the degeneracy between redshift and luminosity in flux-density limited samples. To overcome this limitation, we present far-infrared Herschel observations of 74 radio-loud quasars (RLQs), 72 radio-quiet quasars (RQQs) and 27 radio galaxies (RGs), selected at 0.9 < z < 1.1 which span over two decades in optical luminosity. By decoupling luminosity from evolutionary effects, we investigate how the star formation rate (SFR) depends on AGN luminosity, radio-loudness and orientation. We find that: 1) the SFR shows a weak correlation with the bolometric luminosity for all AGN sub-samples, 2) the RLQs show a SFR excess of about a factor of 1.4 compared to the RQQs, matched in terms of black hole mass and bolometric luminosity, suggesting that either positive radio-jet feedback or radio AGN triggering are linked to star-formation triggering and 3) RGs have lower SFRs by a factor of 2.5 than the RLQ sub-sample with the same BH mass and bolometric luminosity. We suggest that there is some jet power threshold at which radio-jet feedback switches from enhancing star formation (by compressing gas) to suppressing it (by ejecting gas). This threshold depends on both galaxy mass and jet power.

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Energetics of the molecular gas in the H₂luminous radio galaxy 3C 326: Evidence for negative AGN feedback

Cited by 139 publications

References 130 publications

Molecular gas and nuclear activity in early-type galaxies: any link with radio loudness?

Molecular gas and nuclear activity in early-type galaxies: any link with radio loudness?

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

Observational evidence that positive and negative AGN feedback depends on galaxy mass and jet power

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Energetics of the molecular gas in the H2luminous radio galaxy 3C 326: Evidence for negative AGN feedback

Cited by 139 publications

References 130 publications

Molecular gas and nuclear activity in early-type galaxies: any link with radio loudness?

Molecular gas and nuclear activity in early-type galaxies: any link with radio loudness?

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

Observational evidence that positive and negative AGN feedback depends on galaxy mass and jet power

Contact Info

Product

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Energetics of the molecular gas in the H₂luminous radio galaxy 3C 326: Evidence for negative AGN feedback