Radio AGN in spiral galaxies

Kaviraj, Sugata; Shabala, Stanislav S.; Deller, Adam T.; Middelberg, E.

doi:10.1093/mnras/stv1957

Cited by 33 publications

(32 citation statements)

References 88 publications

(119 reference statements)

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“…systems (e.g., Ledlow et al 1998;Hota et al 2011;Morganti et al 2011;Bagchi et al 2014;Kaviraj et al 2015;Mao et al 2015;Singh et al 2015), and among them, PKS 2004-447 is the only gamma-ray-emitting radio galaxy in which a disky pseudobulge and a stellar bar have been found. Since there is solid observational evidence pointing to the presence of fully developed relativistic jets emanating from PKS2004-447 Schulz et al 2016), it arises that the same spinning black hole conditions that enable the production of prominent relativistic jets can be met, even if non-major merger related black hole fueling mechanisms have ignited the AGN.…”

Section: (∼7×10mentioning

confidence: 99%

Discovery of a Pseudobulge Galaxy Launching Powerful Relativistic Jets

Kotilainen

León-Tavares

Olguín-Iglesias

et al. 2016

ApJ

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Supermassive black holes launching plasma jets at close to the speed of light, producing gamma-rays, have ubiquitously been found to be hosted by massive elliptical galaxies. Since elliptical galaxies are generally believed to be built through galaxy mergers, active galactic nuclei (AGN) launching relativistic jets are associated with the latest stages of galaxy evolution. We have discovered a pseudobulge morphology in the host galaxy of the gammaray AGN PKS 2004-447. This is the first gamma-ray emitter radio-loud AGN found to have been launched from a system where both the black hole and host galaxy have been actively growing via secular processes. This is evidence of an alternative black hole-galaxy co-evolutionary path to develop powerful relativistic jets, which is not merger driven.

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Section: (∼7×10mentioning

confidence: 99%

Discovery of a Pseudobulge Galaxy Launching Powerful Relativistic Jets

Kotilainen

León-Tavares

Olguín-Iglesias

et al. 2016

ApJ

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“…In fact, central SF activity in our VLBI-detected objects is likely to be rather limited given that most of their FIRST flux is unresolved (90 objects have more than 80% of their total FIRST flux density in an unresolved component) and that generally (86 objects, or 83%) more than half of this compact emission is found in the VLBI component. Furthermore, VLBI-detected galaxies reside primarily on the red-sequence of passively-evolving system in the UV-optical color-magnitude diagram (Kaviraj et al 2015a), which is sensitive to even small fractions of young stars (Yi et al 2005;Kaviraj et al 2007). …”

Section: Mjive-20 Detected Objectsmentioning

confidence: 99%

“…This selection would naturally sample high-density environments such as galaxy clusters where a hot-gas medium is available for the AGN to work against and produce detectable radio lobes. On the other hand, the mJIVE-20 survey is capable of detecting compact radio AGN regardless of local environment and thus probes AGNs in the general galaxy population that largely inhabits relatively low-density environments (Kaviraj et al 2015a). The working of radio AGN activity may thus be different in these two samples, being directly fuelled by the cooling of hot gas in Figure 1.…”

Section: Mjive-20 Detected Objectsmentioning

confidence: 99%

Cold-gas outflows in typical low-redshift galaxies are driven by star formation, not AGN

Sarzi

Kaviraj

Nedelchev

et al. 2015

Monthly Notices of the Royal Astronomical Society: Letters

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Energetic feedback from active galactic nuclei (AGN) is an important ingredient for regulating the star-formation history of galaxies in models of galaxy formation, which makes it important to study how AGN feedback actually occurs in practice. In order to catch AGNs in the act of quenching star formation we have used the interstellar Na I λλ5890, 5895 (NaD) absorption lines to look for cold-gas outflows in a sample of 456 nearby galaxies for which we could unambigously ascertain the presence of radio AGN activity, thanks to radio imaging at milli-arcsecond scales. While compact radio emission indicating a radio AGN was found in 103 galaxies (23% of the sample), and 23 objects (5%) exhibited NaD absorption-line kinematics suggestive of cold-gas outflows, not one object showed evidence of a radio AGN and of a cold-gas outflow simultaneously. Radio AGN activity was found predominantly in early-type galaxies, while cold-gas outflows were mainly seen in spiral galaxies with central star-formation or composite star-formation/AGN activity. Optical AGNs also do not seem capable of driving galactic winds in our sample. Our work adds to a picture of the low-redshift Universe where cold-gas outflows in massive galaxies are generally driven by star formation and where radio-AGN activity occurs most often in systems in which the gas reservoir has already been significantly depleted.

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“…Ledlow et al 2001). The VLBI-detected LTGs will be the subject of a forthcoming paper (Kaviraj et al 2015). Given the dearth of radio AGN in the LTGs, our subsequent analysis focuses only on the ETG population.…”

Section: The Final Galaxy Sample and Basic Propertiesmentioning

confidence: 99%

The triggering of local AGN and their role in regulating star formation

Kaviraj

Shabala

Deller

et al. 2015

Mon. Not. R. Astron. Soc.

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We explore the processes that trigger local AGN and the role of these AGN in regulating star formation, using ∼550 nearby galaxies observed by the mJy Imaging VLBA Exploration at 20 cm (mJIVE) survey. The 10 7 K brightness temperature required for an mJIVE detection cannot be achieved via star formation alone, allowing us to unambiguously detect nearby radio AGN and study their role in galaxy evolution. Radio AGN are an order of magnitude more common in early-type galaxies (ETGs) than in their late-type counterparts. The VLBI-detected ETGs in this study have a similar stellar mass distribution to their undetected counterparts, are typically not the central galaxies of clusters and exhibit merger fractions that are significantly higher than in the average ETG. This suggests that these radio AGN (which have VLBI luminosities >10 22 W Hz −1 ) are primarily fuelled by mergers, and not by internal stellar mass-loss or cooling flows. Our radio AGN are a factor of ∼3 times more likely to reside in the UV-optical red sequence than the average ETG. Furthermore, typical AGN lifetimes (a few 10 7 yr) are much shorter than the transit times from blue cloud to red sequence (∼1.5 Gyr). This indicates that nearby (merger-triggered) AGN appear several dynamical time-scales into the associated star formation episode. This implies that such AGN typically couple only to residual gas, at a point where star formation has already declined significantly, and are, therefore, unlikely to play a significant role in regulating the star formation episode.

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Radio AGN in spiral galaxies

Cited by 33 publications

References 88 publications

Discovery of a Pseudobulge Galaxy Launching Powerful Relativistic Jets

Discovery of a Pseudobulge Galaxy Launching Powerful Relativistic Jets

Cold-gas outflows in typical low-redshift galaxies are driven by star formation, not AGN

The triggering of local AGN and their role in regulating star formation

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