Compact sources in the Bologna Complete Sample: high-resolution VLA observations and optical data

Liuzzo, E.; Buttiglione, S.; Giovannini, G.; Giroletti, M.; Capetti, A.; Taylor, G. B.

doi:10.1051/0004-6361/201220012

Cited by 6 publications

(5 citation statements)

References 73 publications

(139 reference statements)

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“…We do not use it in statistical considerations. A similar source (B2 0722+30) was found by Liuzzo et al (2013), who studied a sample of compact FRI sources. In JVLA images (Baldi et al 2019a) J0907+32 shows a nuclear emission and a A104, page 4 of 12 symmetric structure identified with the disc emission easily confused with two-sided jets.…”

Section: Resultssupporting

confidence: 67%

Jets in FR0 radio galaxies

Giovannini

Baldi

Capetti

et al. 2023

A&A

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Context. The local radio-loud AGN population is dominated by compact sources named FR0s. These sources show features, for example the host type, the mass of the supermassive black hole (SMBH), and the multi-band nuclear characteristics, that are similar to those of FRI radio galaxies. However, in the radio band, while FR0 and FRI share the same nuclear properties, the kiloparsec-scale diffuse component dominant in FRI is missing in FR0s. Previous very-long-baseline interferometry (VLBI) observations of a small sample of FR0s show a complex structure, mostly symmetric (two-sided jets) with respect to the central core. Aims. With this project we would like to study the parsec-scale structure in FR0s in comparison with that of FRI sources. Jets in FRI are relativistic on the parsec scale and decrease their velocity becoming subrelativistic on the kiloparsec scale. We would like to test whether this result also applies to the jets in FR0s or, alternatively, whether they are subrelativistic on the parsec scale. This might be the reason why they are unable to grow, because of instabilities, related to a low jet bulk velocity. Methods. To this end we observed 18 FR0 galaxies with the VLBA at 1.5 and 5 GHz and/or with the EVN at 1.7 GHz and produced detailed images at milliarcsec resolution of their nuclear emission to study the jet and core structure. Results. All sources have been detected but one. Four sources are unresolved, even in these high-resolution images; jets have been detected in all other sources. We derived the distribution of the jet-to-counter-jet ratio of FR0s and found that it is significantly different from that of FRIs, suggesting different jet bulk speed velocities. Conclusions. Combining the present data with published data of FR0 with VLBI observations, we derive that the radio structure of FR0 galaxies shows strong evidence that parsec-scale jets in FR0 sources are mildly relativistic with a bulk velocity on the order of 0.5c or less. A jet structure with a thin inner relativistic spine surrounded by a low-velocity sheath could be in agreement with the SMBH and jet launch region properties.

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Section: Resultssupporting

confidence: 67%

Jets in FR0 radio galaxies

Giovannini

Baldi

Capetti

et al. 2023

A&A

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“…8) suggests possible extended emission. Liuzzo et al (2013) characterised the source as a compact source with two sides lobes with extensions to the south.…”

Section: J12201+2916mentioning

confidence: 99%

Compact symmetric objects and supermassive binary black holes in the VLBA Imaging and Polarimetry Survey

Tremblay

Taylor

Ortiz

et al. 2016

Mon. Not. R. Astron. Soc.

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We present multi-frequency Very Long Baseline Array (VLBA) follow-up observations of VLBA Imaging and Polarimetry Survey sources identified as likely compact symmetric objects (CSOs) or super-massive binary black holes (SBBHs). We also present new spectroscopic redshifts for 11 sources observed with the Hobby-Eberly Telescope. While no new SBBHs can be confirmed from these observations, we have identified 24 CSOs in the sample, 15 of which are newly designated, and refuted 52 candidates leaving 33 unconfirmed candidates. This is the first large uniform sample of CSOs which can be used to elicit some of the general properties of these sources, including morphological evolution and environmental interaction. We have detected polarised emission from two of these CSOs the properties of which are consistent with Active Galactic Nuclei unification schemes.

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“…Radio emission in extragalactic radioloud AGNs permits us to investigate the "largescale" (i.e. from pc to Mpc size) evolution of relativistic jets and their interactions with the environments (see e.g., Liuzzo et al 2013;Nulsen et al 2013;Fabian 2012, and references therein).…”

Section: Introductionmentioning

confidence: 99%

RADIO-WEAK BL LAC OBJECTS IN THEFERMIERA

Massaro

Marchesini

D’Abrusco

et al. 2017

ApJ

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The existence of "radio weak BL Lac objects" (RWBLs) has been an open question, still unsolved, since the discovery that quasars could be radio-quiet or radio-loud. Recently several groups identified RWBL candidates, mostly found while searching for low energy counterparts of the unidentified/unassociated gamma-ray sources listed in the Fermi catalogs. Confirming RWBLs is a challenging task since they could be confused with white dwarfs or weak emission line quasars when there are not sufficient data to precisely draw their broad band spectral energy distribution and their classification is mainly based on a featureless optical spectra. Motivated by the recent discovery that Fermi BL Lacs appear to have very peculiar mid-IR emission, we show that it is possible to distinguish between WDs, WELQs and BL Lacs using the [3.4]-[4.6]-[12]µm color-color plot built using the WISE magnitudes when the optical spectrum is available. On the basis of this analysis, we identify WISE J064459.38+603131 and WISE J141046.00+740511.2 as the first two genuine RWBLs, both potentially associated with Fermi sources. Finally, to strengthen our identification of these objects as true RWBLs, we present multifrequency observations for these two candidates to show that their spectral behavior is indeed consistent with those of the BL Lac population.

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Compact sources in the Bologna Complete Sample: high-resolution VLA observations and optical data

Cited by 6 publications

References 73 publications

Jets in FR0 radio galaxies

Jets in FR0 radio galaxies

Compact symmetric objects and supermassive binary black holes in the VLBA Imaging and Polarimetry Survey

RADIO-WEAK BL LAC OBJECTS IN THEFERMIERA

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