THE<i>SPITZER</i>VIEW OF FR I RADIO GALAXIES: ON THE ORIGIN OF THE NUCLEAR MID-INFRARED CONTINUUM

Leipski, C.; Antonucci, Robert; Ogle, Patrick; Whysong, D.

doi:10.1088/0004-637x/701/2/891

Cited by 56 publications

(113 citation statements)

References 174 publications

(357 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The 10-20 μm ISOCAM observations of HEG 3C 98 and BLRG 3C 445 (Siebenmorgen et al 2004a) infer the same fluxes as our measurements. On the other hand, our non-detection and the detection with the Spitzer IRS (3.7 slit width) (Leipski et al 2009) show that the mid-infrared emission in FR-I 3C 270 must be of an extended nature compared to the VLT/VISIR 0.36 beam. Possibly inconsistent with this conclusion is that this extended emission probably originates from star formation and in situ heating, yet PAHs are weak or absent in the high-quality Spitzer spectrum.…”

Section: Visir Observations and Data Reductionmentioning

confidence: 57%

“…Half (50 ± 18 percent) have the strength of Centaurus A, while 3/8 (38±17 percent) are ten times brighter and 1/8 (13±12 percent) is ten times weaker. Four of the sources have published Spitzer IRS spectra (Horst et al 2009;Leipski et al 2009), which support the non-thermal, PAH-free nature of the nuclei. An exception might be 3C 270, for which an excess IRS mid-infrared radiation is argued to originate in 200K warm nuclear dust.…”

Section: The Nature Of the Mid-infrared Emissionmentioning

confidence: 82%

“…This spectrum can also be fitted by a parabolic function, which is found to be a good approximation (Landau et al 1986;Andreani et al 2002;Leipski et al 2009). Both type of fits and the nuclear mid-infrared luminosity of log νL ν = 41.8 erg s −1 found by (Martel et al 1999), and some contain high molecular gas masses as deduced from high resolution CO maps (Okuda et al 2005;Das et al 2005).…”

Section: Introductionmentioning

confidence: 94%

“…Landau et al 1986;Andreani et al 2002;Leipski et al 2009). The values of the curvatures and the goodness of fit, as indicated by the reduced χ 2 parameter, are listed in Table 4.…”

Section: The Nature Of the Mid-infrared Emissionmentioning

confidence: 99%

“…The other three, 3C 15, 3C 424, and 4C 12.03 have VISIR upper limits that could conceivably represent a small mid-infrared excess. On the basis of its Spitzer IRS spectrum, 3C 15 and 3C 424 are argued to host larger amounts of thermal nuclear emission (Leipski et al 2009). Out of the five LEGs, two LEGs are midinfrared weak, while the other three are uncertain since they have upper limits above the dividing line between weak and strong sources.…”

Section: The Nature Of the Mid-infrared Emissionmentioning

confidence: 99%

See 4 more Smart Citations

Dust tori in radio galaxies

Wolk¹,

Barthel²,

Peletier³

et al. 2010

A&A

View full text Add to dashboard Cite

Aims. We investigate the quasar -radio galaxy unification scenario and detect dust tori within radio galaxies of various types. Methods. Using VISIR on the VLT, we acquired sub-arcsecond (∼0.40 ) resolution N-band images, at a wavelength of 11.85 μm, of the nuclei of a sample of 27 radio galaxies of four types in the redshift range z = 0.006−0.156. The sample consists of 8 edge-darkened, low-power Fanaroff-Riley class I (FR-I) radio galaxies, 6 edge-brightened, class II (FR-II) radio galaxies displaying low-excitation optical emission, 7 FR-IIs displaying high-excitation optical emission, and 6 FR-II broad emission line radio galaxies. Out of the sample of 27 objects, 10 nuclei are detected and several have constraining non-detections at sensitivities of 7 mJy, the limiting flux a point source has when detected with a signal-to-noise ratio of 10 in one hour of source integration. Results. On the basis of the core spectral energy distributions of this sample we find clear indications that many FR-I and several low-excitation FR-II radio galaxies do not contain warm dust tori. At least 57 ± 19 percent of the high-excitation FR-IIs and almost all of the broad line radio galaxies exhibit excess infrared emission, which must be attributed to warm dust reradiating accretion activity. The FR-I and low-excitation FR-II galaxies are all of low efficiency, which is calculated as the ratio of bolometric to Eddington luminosity L bol /L Edd < 10 −3 . This suggests that thick tori are absent at low accretion rates and/or low efficiencies. The high-excitation FR-II galaxies are a mixed population with three types of nuclei: 1) low efficiency with dust torus; 2) low efficiency with weakly emitting dust torus; and 3) high efficiency with weak dust torus. We argue that the unification viewing angle range 0-45 degrees of quasars should be increased to ∼60 degrees, at least at lower luminosities.

show abstract

Section: Visir Observations and Data Reductionmentioning

confidence: 57%

Section: The Nature Of the Mid-infrared Emissionmentioning

confidence: 82%

Section: Introductionmentioning

confidence: 94%

“…Landau et al 1986;Andreani et al 2002;Leipski et al 2009). The values of the curvatures and the goodness of fit, as indicated by the reduced χ 2 parameter, are listed in Table 4.…”

Section: The Nature Of the Mid-infrared Emissionmentioning

confidence: 99%

Section: The Nature Of the Mid-infrared Emissionmentioning

confidence: 99%

See 3 more Smart Citations

Dust tori in radio galaxies

Wolk¹,

Barthel²,

Peletier³

et al. 2010

A&A

View full text Add to dashboard Cite

show abstract

AGN feedback and star formation in young and old radio galaxies

et al. 2016

View full text Add to dashboard Cite

Powerful radio galaxies show evidence of ongoing active galactic nuclei (AGN) feedback, mainly in the form of fast, massive outflows. Yet, it is not clear how these outflows affect the star formation of their hosts. We investigated the different manifestations of AGN feedback in the evolved 3C 293 radio source, and in the young, reactivated 3C 236. Both sources harbor young star‐forming regions and fast outflows of H I and ionized gas. Due to the different evolution stages of these sources, they are expected to be at different phases of the AGNISM interaction process. Using high spatial resolution observations of CO lines taken with the IRAM Plateau de Bure interferometer, we studied the distribution and kinematics of the molecular gas in these sources, and compared the results with the dust and star‐formation images of the host. We searched for signatures of outflow motions in the CO kinematics, and derived the star formation rate (SFR) and star formation efficiency (SFE) of the host with all available SFR tracers. Based on the gas mass derived from our observations and on the SFR estimates, we compared the star‐formation efficiency of 3C 236 and 3C 293 against a sample of powerful radio galaxies. Our results suggest that the apparently low SFE of evolved radio galaxies is not necessarily due to AGN feedback, but may be caused by an underestimation of the SFR and/or an overestimation of the molecular gas densities in radio galaxies. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

show abstract

Radio AGN in the local universe: unification, triggering and evolution

Tadhunter

2016

Astron Astrophys Rev

149

150

View full text Add to dashboard Cite

Associated with one of the most important forms of active galactic nucleus (AGN) feedback, and showing a strong preference for giant elliptical host galaxies, radio AGN (L_1.4GHz > 10^24 W Hz^-1) are a key sub-class of the overall AGN population. Here I review our current state of understanding of the population of radio AGN at low and intermediate redshifts (z < 0.7), concentrating on their AGN and host galaxy properties, and covering three interlocking themes: the classification of radio AGN and its interpretation; the triggering and fuelling of the jet and AGN activity; and the evolution of the host galaxies. I show that much of the observed diversity in the AGN properties of radio AGN can be explained in terms of a combination of orientation/anisotropy, mass accretion rate, and variability effects. The detailed morphologies of the host galaxies are consistent with the triggering of strong-line radio galaxies (SLRG) in galaxy mergers. However, the star formation properties and cool ISM contents suggest that the triggering mergers are relatively minor in terms of their gas masses in most cases, and would not lead to major growth of the supermassive black holes and stellar bulges; therefore, apart from a minority (<20%) that show evidence for higher star formation rates and more massive cool ISM reservoirs, the SLRG represent late-time re-triggering of activity in mature giant elliptical galaxies. In contrast, the host and environmental properties of weak-line radio galaxies (WLRG) with Fanaroff-Riley class I (FRI) radio morphologies are consistent with more gradual fuelling of the activity via gas accretion at low rates onto the supermassive black holes.Comment: Accepted for publication in Astronomy & Astrophysics Review, 67 pages, 17 figure

show abstract

THESPITZERVIEW OF FR I RADIO GALAXIES: ON THE ORIGIN OF THE NUCLEAR MID-INFRARED CONTINUUM

Cited by 56 publications

References 174 publications

Dust tori in radio galaxies

Dust tori in radio galaxies

AGN feedback and star formation in young and old radio galaxies

Radio AGN in the local universe: unification, triggering and evolution

Contact Info

Product

Resources

About