Toward Understanding the Fanaroff-Riley Dichotomy in Radio Source Morphology and Power

Baum, Stefi A.; Zirbel, Esther; O’Dea, C. P.

doi:10.1086/176202

Cited by 200 publications

(226 citation statements)

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“…This sample contains no examples of radio sources clearly having the other characteristic structure, the FR I type (where the brightness decreases with increasing distance from the core), powered by quasar nuclei. This, together with a consistent picture from similar samples, led some to postulate that there is a deep association between the nature of the central engine and whether the radio structure is type FR I or FR II (Baum, Zirbel, & O'Dea 1995).…”

Section: Introductionmentioning

confidence: 88%

The Optically Powerful Quasar E1821+643 is Associated with a 300 Kiloparsec–Scale FR I Radio Structure

Blundell¹,

Rawlings²

2001

The Astrophysical Journal

113

135

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We present a deep image of the optically powerful quasar E1821ϩ643 at 18 cm made with the Very Large Array. This image reveals radio emission, over 280 h Ϫ1 kpc in extent, elongated way beyond the quasar's host galaxy. Its radio structure has decreasing surface brightness with increasing distance from the bright core, characteristic of FR I sources. Its radio luminosity at 5 GHz falls in the classification for "radio-quiet" quasars (it is only 10 23.9 W Hz Ϫ1 sr Ϫ1 ). Its radio luminosity at 151 MHz (which is 10 25.3 W Hz Ϫ1 sr Ϫ1 ) is at the transition luminosity observed to separate FR I and FR II structures. Hitherto, no optically powerful quasar had been found to have a conventional FR I radio structure. For searches at low frequency, this is unsurprising given current sensitivity and plausible radio spectral indices for radio-quiet quasars. We demonstrate the inevitability of the extent of any FR I radio structures being seriously underestimated by existing targeted follow-up observations of other optically selected quasars, which are typically short exposures of objects, and we discuss the z 1 0.3 implications for the purported radio bimodality in quasars. The nature of the inner arcsecond-scale jet in E1821ϩ643, together with its large-scale radio structure, suggest that the jet axis in this quasar is precessing (cf. Galactic jet sources such as SS 433). A possible explanation for this is that its central engine is a binary whose black holes have yet to coalesce. The ubiquity of precession in radio-quiet quasars, perhaps as a means of reducing the observable radio luminosity expected in highly accreting systems, remains to be established.

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Section: Introductionmentioning

confidence: 88%

The Optically Powerful Quasar E1821+643 is Associated with a 300 Kiloparsec–Scale FR I Radio Structure

Blundell¹,

Rawlings²

2001

The Astrophysical Journal

113

135

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“…This is consistent with the hypothesis that a high black hole mass is necessary but not sufficient to produce a powerful radio source. Other physical parameters such as the spin of the black hole, accretion efficiency, and other large-scale environmental effects may be responsible for the broad dispersion in radio power (e.g., Baum et al 1995;Meier 1999;Wold et al 2007). …”

Section: Relation Between Radio Power and Host Galaxy Properties 43mentioning

confidence: 99%

Constraints on Feedback in the Local Universe: The Relation Between Star Formation and Agn Activity in Early-Type Galaxies

Vaddi

O’Dea

Baum

et al. 2016

ApJ

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We address the relation between star formation and active galactic nucleus (AGN) activity in a sample of 231 nearby (0.0002 < z < 0.0358) early-type galaxies by carrying out a multi-wavelength study using archival observations in the UV, IR, and radio. Our results indicate that early-type galaxies in the current epoch are rarely powerful AGNs, with P 10 WHz 22 1 < -for a majority of the galaxies. Only massive galaxies are capable of hosting powerful radio sources while less massive galaxies are hosts to lower radio power sources. Evidence of ongoing star formation is seen in approximately 7% of the sample. The star formation rate (SFR) of these galaxies is less than 0.1 M e yr −1 . They also tend to be radio faint (P 10 WHzThere is a nearly equal fraction of star-forming galaxies in radio faint (P 10 WHz 22 1 < -) and radio bright galaxies (P 10 WHz 22 1  -) suggesting that both star formation and radio mode feedback are constrained to be very low in our sample. We notice that our galaxy sample and the Brightest Cluster Galaxies follow similar trends in radio power versus SFR. This may be produced if both radio power and SFR are related to stellar mass.

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“…The emission-line luminosity of radio-quiet ellipticals and of FR I galaxies of the same optical magnitude is similar, but if the optical-magnitude to line-luminosity correlation is removed, thereis only a weak residual correlation of line and radio luminosity in FR I galaxies (Baum, Zirbel, & O'Dea 1995). These results suggest that the ionizing source in radio-quiet and FR I ellipticals is the same and is associated with the host galaxy itself.…”

Section: Radio-quiet Elliptieals Versus Fr I Galaxiesmentioning

confidence: 79%

“…Models considering the presence of old UV-bright post-AGB stars are able to explain the observed LINER optical spectrum and the Ha luminosity in bright ellipticals (Binette et al 1994 .…”

Section: Radio-quiet Elliptieals Versus Fr I Galaxiesmentioning

confidence: 95%

“…Other criteria designed to minimize extinction effects in the line ratios (Veilleux & Osterbrock 1987;Ho, Filippenko, & Sargent 1993) Heckman (1980) proposed that LINERs were produced by shocks in a low-density medium. However, several other ionizing mechanisms such as lowluminosity AGNs (Ferland & Netzer 1983), hot high-metallicity O-type stars (Filippenko & Terlevich 1992;Shields 1992), radiative shocks in accretion flows or winds (Dopita & Sutherland 1995), or UV-bright post-AGB stars (Binette et al 1994) have been invoked as the energy sources of LINERs.…”

Section: Following Heckman a Galaxy Is Classified As A Classical Linmentioning

confidence: 99%

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The Nature of the Energy Source in LINERs

Colina

Koratkar

1997

International Astronomical Union Colloquium

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Abstract.LINERs are found in ,,,30% of all bright galaxies, including luminous infrared galaxies. They form a heterogeneous class powered by a variety of ionizing mechanisms such as low-luminosity AGNs, starbursts, shocks, or any combination of these.In early-type spirals, LINERs are powered by a low-luminosity AGN, or by an AGN surrounded by circumnuclear star-forming regions. In luminous infrared galaxies, LINERs are powered by starbursts with associated wind-related extended shocks, and an AGN may play a minor role, if any. LINERs in some FR I radio galaxies show a strong evidence for the presence of a massive central black hole, and there are indications for the existence of shocks in the nuclear disks of these galaxies. Yet, the dominant ionizing mechanism for LINERs in radio-quiet enipticals and FR I host galaxies is still unclear.Multifrequency high spatial resolution imaging and spectroscopy are essential to discriminate among the different ionizing mechanisms present in LINERs.

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Toward Understanding the Fanaroff-Riley Dichotomy in Radio Source Morphology and Power

Cited by 200 publications

References 0 publications

The Optically Powerful Quasar E1821+643 is Associated with a 300 Kiloparsec–Scale FR I Radio Structure

The Optically Powerful Quasar E1821+643 is Associated with a 300 Kiloparsec–Scale FR I Radio Structure

Constraints on Feedback in the Local Universe: The Relation Between Star Formation and Agn Activity in Early-Type Galaxies

The Nature of the Energy Source in LINERs

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