Tracing the merger-driven evolution of active galaxies using the CJF sample

Karouzos, Marios; Britzen, S.; Eckart, A.; Witzel, A.; Zensus, J. A.

doi:10.1051/0004-6361/200913550

Cited by 15 publications

(20 citation statements)

References 174 publications

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“…The connection to AGN activity predicted by simulations is supported by many studies that find high incidences of tidal features associated with AGNs (Treister et al 2012;Cotini et al 2013;Ellison et al 2013;Satyapal et al 2014;Rosario et al 2015), including Karouzos et al (2010), who found that nearly 30% of active galaxies showed signs of an interaction or merger in the optical and infrared. Nazaryan et al (2014) performed an optical study of 180 Markarian galaxy pairs and found that ongoing mergers are 7 times more likely to contain an AGN than interacting pairs.…”

Section: Introductionmentioning

confidence: 54%

“…In simulations, major encounters between similar mass (typically ≤4:1 mass ratio), gas-rich galaxies are predicted to drive gas to the centers of interacting and merging systems triggering new star formation (SF) and fueling an AGN (Volonteri et al 2003;Hopkins et al 2008;Di Matteo et al 2005;Debuhr et al 2011). Many observational studies support the correlation between AGNs and merging systems (Karouzos et al 2010;Treister et al 2012;Cotini et al 2013;Ellison et al 2013;Nazaryan et al 2014;Satyapal et al 2014;Rosario et al 2015). However, other researchers, particularly those working at shorter wavelengths, do not find such a connection (Cisternas et al 2011;Kocevski et al 2012;Fan et al 2014;Scott & Kaviraj 2014;Villforth et al 2014).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Incidence ofWISE-selected obscured AGNs in major mergers and interactions from the SDSS

Weston

McIntosh

Brodwin

et al. 2016

Mon. Not. R. Astron. Soc.

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We use the Wide-field Infrared Survey Explorer (WISE) and the Sloan Digital Sky Survey (SDSS) to confirm a connection between dust-obscured active galactic nuclei (AGNs) and galaxy merging. Using a new, volume-limited (z ≤ 0.08) catalog of visually-selected major mergers and galaxy-galaxy interactions from the SDSS, with stellar masses above 2 × 10 10 M , we find that major mergers (interactions) are 5-17 (3-5) times more likely to have red [3.4]−[4.6] colors associated with dust-obscured or 'dusty' AGNs, compared to nonmerging galaxies with similar masses. Using published fiber spectral diagnostics, we map thecolors of different emission-line galaxies and find one-quarter of Seyferts have colors indicative of a dusty AGN. We find that AGNs are five times more likely to be obscured when hosted by a merging galaxy, half of AGNs hosted by a merger are dusty, and we find no enhanced frequency of optical AGNs in merging over non-merging galaxies. We conclude that undetected AGNs missed at shorter wavelengths are at the heart of the ongoing AGN-merger connection debate. The vast majority of mergers hosting dusty AGNs are star-forming and located at the centers of M halo < 10 13 M groups. Assuming plausibly short duration dusty-AGN phases, we speculate that a large fraction of gas-rich mergers experience a brief obscured AGN phase, in agreement with the strong connection between central star formation and black hole growth seen in merger simulations.

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Section: Introductionmentioning

confidence: 54%

Section: Introductionmentioning

confidence: 99%

Incidence ofWISE-selected obscured AGNs in major mergers and interactions from the SDSS

Weston

McIntosh

Brodwin

et al. 2016

Mon. Not. R. Astron. Soc.

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“…The X-ray properties have been studied and correlated with their VLBI properties (Britzen et al 2007a). The evolution of active galaxies, in the context of the merger-driven evolution scheme (e.g., Hopkins et al 2006), was also investigated with the help of the CJF, identifying candidate CJF sources in different evolutionary stages, including new binary black hole candidates (Karouzos et al 2010). …”

Section: The Cjf Samplementioning

confidence: 99%

Deconstructing blazars: A different scheme for jet kinematics in flat-spectrum AGN

Karouzos¹,

Britzen²,

Witzel³

et al. 2012

A&A

Self Cite

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Context. Recent VLBI studies of the morphology and kinematics of individual BL Lac objects (S5 1803+784, PKS 0735+178, etc.) have revealed a new paradigm for the pc-scale jet kinematics of these sources. Unlike the apparent superluminal outward motions usually observed in blazars, most, if not all, jet components in these sources appear to be stationary with respect to the core, while exhibiting strong changes in their position angles. As a result, the jet ridge lines of these sources evolve substantially, at times forming a wide channel-flow. Aims. We investigate the Caltech-Jodrell Bank flat-spectrum (CJF) sample of radio-loud active galaxies to study this new kinematic scenario for flat-spectrum AGN. Comparing BL Lac objects and quasars in the CJF, we look for differences in the kinematics and morphologies of their jet ridge lines. The large number of sources in the CJF sample, together with the excellent kinematical data available, allow us to perform a robust statistical analysis in this context. Methods. We develop a number of tools to extract information about the apparent linear and angular evolution of the CJF jet ridge lines, as well as their morphology. We study both the radial and non-radial apparent motions in the CJF jets. A statistical analysis of the extracted information allows us to test this new kinematic scenario and assess the importances of the radial and non-radial motions in flat-spectrum AGN jets in general and especially in BL Lacs compared to quasars. We also use these tools to check the kinematics for (multi-wavelength) variable AGN. Results. We find that approximately half of the sample display appreciable apparent jet widths (>10 degrees), with BL Lac jet ridge lines showing significantly larger apparent widths than those of both quasars and radio galaxies. In addition, BL Lac jet ridge lines are found to change their apparent width more strongly. Finally, BL Lac jet ridge lines show the least apparent linear evolution, which translates into the smallest apparent expansion speeds for their components. We find compelling evidence supporting a substantially different kinematic scenario for flat-spectrum radio-AGN jets and in particular for BL Lac objects. In addition, we find that variability is closely related to the properties of a source's jet ridge line. Variable quasars are found to have "BL Lac like" behavior, relative to their non-variable counterparts.

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“…in the center of galaxies, now commonly referred to as a Active Galactic Nuclei (AGN), can be triggered in a variety of ways. Merger driven models (Hopkins et al 2008;Ramos Almeida et al 2010;Karouzos et al 2010;Sabater et al 2013), induce accretion by both disrupting existing cold gas reservoirs in the merging galaxies and via the direct inflow of gas from the merger event itself. Alternatively, there is evidence to support the triggering of AGN in non-merging galaxies (Crenshaw et al 2003, Schawinski et al 2014, Draper et al 2012 and references therein) via supernova winds, stellar bars and the efficient inflow of cold gas from the intergalactic medium.…”

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confidence: 99%

Radio galaxies in ZFOURGE/NMBS: no difference in the properties of massive galaxies with and without radio-AGN out toz = 2.25

Rees

Spitler

Norris

et al. 2015

Mon. Not. R. Astron. Soc.

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In order to reproduce the high-mass end of the galaxy mass-distribution, some process must be responsible for the suppression of star-formation in the most massive of galaxies. Commonly Active Galactic Nuclei (AGN) are invoked to fulfil this role, but the exact means by which they do so is still the topic of much debate, with studies finding evidence for both the suppression and enhancement of star-formation in AGN hosts. Using the ZFOURGE and NMBS galaxy surveys, we investigate the host galaxy properties of a mass-limited (M 10 10.5 M ), high-luminosity (L 1.4 > 10 24 W Hz −1 ) sample of radio-loud Active Galactic Nuclei to a redshift of z = 2.25. In contrast to low redshift studies, which associate radio-AGN activity with quiescent hosts, we find that the majority of z > 1.5 radio-AGN are hosted by star-forming galaxies. Indeed, the stellar populations of radio-AGN are found to evolve with redshift in a manner that is consistent with the non-AGN mass-similar galaxy population. Interestingly, we find the radio-AGN fraction is constant across a redshift range of 0.25 z < 2.25, perhaps indicating that the radio-AGN duty cycle has little dependence on redshift or galaxy type. We do however see a strong relation between the radio-AGN fraction and stellar mass, with radio-AGN becoming rare below ∼ 10 10.5 M or a halo-mass of 10 12 M . This halo-mass threshold is in good agreement with simulations that initiate radio-AGN feedback at this mass limit. Despite this we find that radio-AGN host star-formation rates are consistent with the non-AGN mass-similar galaxy sample, suggesting that while radio-AGN are in the right place to suppress star-formation in massive galaxies they are not necessarily responsible for doing so.

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Tracing the merger-driven evolution of active galaxies using the CJF sample

Cited by 15 publications

References 174 publications

Incidence ofWISE-selected obscured AGNs in major mergers and interactions from the SDSS

Incidence ofWISE-selected obscured AGNs in major mergers and interactions from the SDSS

Deconstructing blazars: A different scheme for jet kinematics in flat-spectrum AGN

Radio galaxies in ZFOURGE/NMBS: no difference in the properties of massive galaxies with and without radio-AGN out toz = 2.25

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