scholarly journals Feeding and feedback in nuclei of galaxies

2020 ◽  
Vol 15 (S359) ◽  
pp. 307-311
Author(s):  
Anelise Audibert ◽  
Françoise Combes ◽  
Santiago García-Burillo ◽  
Kalliopi Dasyra
Keyword(s):  
High Resolution ◽  
Active Galactic Nuclei ◽  
Galaxy Evolution ◽  
Galactic Nuclei ◽  
Radio Galaxies ◽  
Host Galaxy ◽  
Molecular Gas ◽  
Molecular Outflows ◽  
Radio Jets ◽  
The Impact

AbstractOur aim is to explore the close environment of Active Galactic Nuclei (AGN) and its connection to the host galaxy through the morphology and dynamics of the cold gas inside the central kpc in nearby AGN. We report Atacama Large Millimeter/submillimeter Array (ALMA) observations of AGN feeding and feedback caught in action in NGC613 and NGC1808 at high resolution (few pc), part of the NUclei of GAlaxies (NUGA) project. We detected trailing spirals inside the central 100 pc, efficiently driving the molecular gas into the SMBH, and molecular outflows driven by the AGN. We present preliminary results of the impact of massive winds induced by radio jets on galaxy evolution, based on observations of radio galaxies from the ALMA Radio-source Catalogue.

scholarly journals LoTSS DR1: Double-double radio galaxies in the HETDEX field

2019 ◽  
Vol 622 ◽  
pp. A13 ◽  
Author(s):  
V. H. Mahatma ◽  
M. J. Hardcastle ◽  
W. L. Williams ◽  
P. N. Best ◽  
J. H. Croston ◽  
...  
Keyword(s):  
Life Cycle ◽  
Active Galactic Nuclei ◽  
Galaxy Evolution ◽  
Control Sample ◽  
Galactic Nuclei ◽  
Radio Galaxies ◽  
Host Galaxy ◽  
Host Galaxies ◽  
Significant Difference ◽  
Double Radio Galaxies

Context. Double-double radio galaxies (DDRGs) represent a short but unique phase in the life-cycle of some of the most powerful radio-loud active galactic nuclei (RLAGN). These galaxies display large-scale remnant radio plasma in the intergalactic medium left behind by a past episode of active galactic nuclei (AGN) activity, and meanwhile, the radio jets have restarted in a new episode. The knowledge of what causes the jets to switch off and restart is crucial to our understanding of galaxy evolution, while it is important to know if DDRGs form a host galaxy dichotomy relative to RLAGN. Aims. The sensitivity and field of view of LOFAR enables the observation of DDRGs on a population basis rather than single-source observations. Using statistical comparisons with a control sample of RLAGN, we may obtain insights into the nature of DDRGs in the context of their host galaxies, where physical differences in their hosts compared to RLAGN as a population may allow us to infer the conditions that drive restarting jets. Methods. We utilised the LOFAR Two-Metre Sky Survey (LoTSS) DR1, using a visual identification method to compile a sample of morphologically selected candidate DDRGs, showing two pairs of radio lobes. To confirm the restarted nature in each of the candidate sources, we obtained follow-up observations with the Karl. G. Jansky Very Large Array (VLA) at higher resolution to observe the inner lobes or restarted jets, the confirmation of which created a robust sample of 33 DDRGs. We created a comparison sample of 777 RLAGN, matching the luminosity distribution of the DDRG sample, and compared the optical and infrared magnitudes and colours of their host galaxies. Results. We find that there is no statistically significant difference in the brightness of the host galaxies between double-doubles and single-cycle RLAGN. The DDRG and RLAGN samples also have similar distributions in WISE mid-infrared colours, indicating similar ages of stellar populations and dust levels in the hosts of DDRGs. We conclude that DDRGs and “normal” RLAGN are hosted by galaxies of the same type, and that DDRG activity is simply a normal part of the life cycle of RLAGN. Restarted jets, particularly for the class of low-excitation radio galaxies, rather than being a product of a particular event in the life of a host galaxy, must instead be caused by smaller scale changes, such as in the accretion system surrounding the black hole.

scholarly journals Combining LOFAR and Apertif Data for Understanding the Life Cycle of Radio Galaxies

Galaxies ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 88
Author(s):  
Raffaella Morganti ◽  
Nika Jurlin ◽  
Tom Oosterloo ◽  
Marisa Brienza ◽  
Emanuela Orrú ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Phased Array ◽  
Low Frequency ◽  
Galactic Nuclei ◽  
Radio Galaxies ◽  
Host Galaxy ◽  
Evolutionary Stage ◽  
Spectral Indices ◽  
Feed System ◽  
Lockman Hole

Active galactic nuclei (AGN) at the centres of galaxies can cycle between periods of activity and of quiescence. Characterising the duty-cycle of AGN is crucial for understanding their impact on the evolution of the host galaxy. For radio AGN, their evolutionary stage can be identified from a combination of morphological and spectral properties. We summarise the results we have obtained in the last few years by studying radio galaxies in various crucial phases of their lives, such as remnant and restarted sources. We used morphological information derived from LOw Frequency ARray (LOFAR) images at 150 MHz, combined with resolved spectral indices maps, obtained using recently released images at 1400 MHz from the APERture Tile In Focus (Apertif) phased-array feed system installed on the Westerbork Synthesis Radio Telescope. Our study, limited so far to the Lockman Hole region, has identified radio galaxies in the dying and restarted phases. We found large varieties in their properties, relevant for understanding their evolutionary stage. We started by quantifying their occurrences, the duration of the ‘on’ (active) and ‘off’ (dying) phase, and we compared the results with models of the evolution of radio galaxies. In addition to these extreme phases, the resolved spectral index images can also reveal interesting secrets about the evolution of apparently normal radio galaxies. The spectral information can be connected with, and used to improve, the Fanaroff–Riley classification, and we present one example of this, illustrating what the combination of the LOFAR and Apertif surveys now allow us to do routinely.

The role of active galactic nuclei in galaxy evolution in terms of radial pressure

2019 ◽  
Vol 15 (S356) ◽  
pp. 299-301
Author(s):  
Biressa Tolu ◽  
Abate Feyissa
Keyword(s):  
Active Galactic Nuclei ◽  
Galaxy Evolution ◽  
Galactic Nuclei ◽  
Spherical Geometry ◽  
Radial Pressure ◽  
Radial Component ◽  
Host Galaxy ◽  
Theoretical Ground ◽  
De Sitter

AbstractIrrespective of whether Active Galactic Nuclei (AGN) is cored with Supermassive Black Holes (SMBH) or not, there is a general consensus that observations indicate that the AGN plays fundamental role in galaxy evolution. The accretion disc powered fueling of the AGN and counter-feedback on its environment in the form of stress-energy-momentum along the radial component and an associated polodial jets seems viable model. On the theoretical ground there is no unified theory that compromise the observations. But there are pull of such diverse physics simulated to describe the observational works. So, there is unsettled theoretical framework how the activity of the AGN plays role in the evolution of host galaxy. Motivated by this we studied the role of AGN on its host galaxy evolution where General relativistic (GR) Magnetohydrodynamics (MHD) equation is considered to derive radial pressure that invokes star forming cold gases. Methodologically the central engine of the AGN is considered with SMBH/pseudo-SMBH. Locally, around the AGN, Reissner-Nordstrom-de Sitter metric is considered that reduces to the Schwarzschoild-de Sitter (SdS) background. Geometrically, a simple spherical geometry is superimposed with central disc structure assumed by cored void mass ablating model. The results of the work indicates that the AGN plays role in galaxy evolution, especially in the nearby environment. Also we report that the adjacent envelope to the AGN seems quiet with no activity in formation.

scholarly journals The recurrent nuclear activity of Fornax A and its interaction with the cold gas

2020 ◽  
Vol 15 (S359) ◽  
pp. 141-146
Author(s):  
F. M. Maccagni ◽  
P. Serra ◽  
M. Murgia ◽  
F. Govoni ◽  
K. Morokuma-Matsui ◽  
...  
Keyword(s):  
High Resolution ◽  
Interstellar Medium ◽  
Shell Morphology ◽  
Host Galaxy ◽  
Molecular Gas ◽  
Nuclear Activity ◽  
Radio Jets ◽  
Multiple Episodes ◽  
Cold Gas

AbstractSensitive (noise ∼16 μJy beam−1), high-resolution (∼10″) MeerKAT observations of show that its giant lobes have a double-shell morphology, where dense filaments are embedded in a diffuse and extended cocoon, while the central radio jets are confined within the host galaxy. The spectral radio properties of the lobes and jets of reveal that its nuclear activity is rapidly flickering. Multiple episodes of nuclear activity must have formed the radio lobes, for which the last stopped 12 Myr ago. More recently (∼3 Myr ago), a less powerful and short (≲1 Myr) phase of nuclear activity generated the central jets. The distribution and kinematics of the neutral and molecular gas in the centre give insights on the interaction between the recurrent nuclear activity and the surrounding interstellar medium.

scholarly journals Feedback from quasars: The prevalence and impact of radio jets

2019 ◽  
Vol 15 (S356) ◽  
pp. 253-253
Author(s):  
Miranda Jarvis
Keyword(s):  
Feedback Mechanism ◽  
Molecular Gas ◽  
Star Forming ◽  
Molecular Outflows ◽  
Radio Jets ◽  
Integral Field Spectroscopy ◽  
Multi Wavelength ◽  
The Impact ◽  
Gas Supply

AbstractI will present our ongoing multi-wavelength study on the prevalence and impact of radio jets in a sample of z < 0.2 type 2 ‘obscured’ quasars who’s high bolometric luminosities make them ideal local analogues of distant, more common, quasars. Despite being classified as ‘radio quiet’ (log L[1.4GHz] = 23.3 - 24.4 W/Hz), our high spatial resolution (∼0.25”) radio observations (VLA and eMERLIN) reveal jet like structures on 1–25kpc scales in ∼80% of the sample. Our integral field spectroscopy reveals jet-ISM interaction and outflows in all cases. Our work suggests that radio jets are an important feedback mechanism even during a typical ‘quasar’ phase. Using ALMA and APEX we are now investigating the impact of these jets and outflows on the molecular, star forming, gas; looking for signs of depletion and excitation. Preliminary results suggest a depleted molecular gas supply in these sources. I will present all of these results, focused on our pilot study of 10 targets and then introduce our on-going work on an expanded sample of 42 low-redshift quasars. Our latest results come from MUSE/AO and ALMA from which we are carefully characterising the properties of the ionised and molecular outflows at sub-kpc resolution.

scholarly journals Black Hole Masses and Host Galaxy Evolution of Radio‐Loud Active Galactic Nuclei

2005 ◽  
Vol 631 (2) ◽  
pp. 762-772 ◽  
Author(s):  
Jong‐Hak Woo ◽  
C. Megan Urry ◽  
Roeland P. van der Marel ◽  
Paulina Lira ◽  
Jose Maza
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galaxy Evolution ◽  
Galactic Nuclei ◽  
Host Galaxy ◽  
Black Hole Masses

scholarly journals The physical properties and impact of AGN outflows from high to low redshift

2019 ◽  
Vol 15 (S359) ◽  
pp. 212-220
Author(s):  
Giacomo Venturi ◽  
Alessandro Marconi
Keyword(s):  
Physical Properties ◽  
Active Galactic Nuclei ◽  
Galaxy Evolution ◽  
Critical Role ◽  
Galactic Nuclei ◽  
Observational Evidence ◽  
Host Galaxies ◽  
Major Player ◽  
The Impact ◽  
Kinematic Properties

AbstractFeedback from active galactic nuclei (AGN) on their host galaxies, in the form of gas outflows capable of quenching star formation, is considered a major player in galaxy evolution. However, clear observational evidence of such major impact is still missing; uncertainties in measuring outflow properties might be partly responsible because of their critical role in comparisons with models and in constraining the impact of outflows on galaxies. Here we briefly review the challenges in measuring outflow physical properties and present an overview of outflow studies from high to low redshift. Finally, we present highlights from our MAGNUM survey of nearby AGN with VLT/MUSE, where the high intrinsic spatial resolution (down to ˜ 10 pc) allows us to accurately measure the physical and kinematic properties of ionised gas outflows.

Feeding and feedback in the nucleus of NGC 613

2019 ◽  
Vol 15 (S359) ◽  
pp. 364-365
Author(s):  
Patrícia da Silva ◽  
J. E. Steiner ◽  
R. B. Menezes
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Hii Regions ◽  
Stellar Populations ◽  
Host Galaxy ◽  
Molecular Gas ◽  
X Rays ◽  
Supermassive Black Hole ◽  
Feeding Process

AbstractActive Galactic Nuclei (AGN) are objects in which a supermassive black hole is fed by gas and, as this generates energy, can ionise the environment and interact with it by jets and winds. This work is focused on the processes of feeding and feedback in the nucleus of NGC 613. This object is a case in which both phenomena can be studied in some detail. The kinematics and morphology of the molecular gas trace the feeding process while the ionization cone, seen in [O iii]λ5007 and soft X-rays, as well as the radio jet and wind/outflows are associated with feedback processes. In addition, we see 10 HII regions, associated with nuclear and circumnuclear young stellar populations, dominant in the optical, that makes the analysis complicated, though more interesting. For all these phenomena, NGC 613 nucleus is a vibrant example of the interplay between the AGN and the host galaxy.

scholarly journals The rise of active galactic nuclei in the galaxy evolution and assembly semi-analytic model

2020 ◽  
Vol 496 (3) ◽  
pp. 3943-3960
Author(s):  
Fabio Fontanot ◽  
Gabriella De Lucia ◽  
Michaela Hirschmann ◽  
Lizhi Xie ◽  
Pierluigi Monaco ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Active Galactic Nuclei ◽  
Galaxy Evolution ◽  
Large Fraction ◽  
Formation Rate ◽  
Galactic Nuclei ◽  
Analytic Model ◽  
The Galaxy ◽  
The Impact ◽  
Cold Gas

ABSTRACT We present a new implementation of the GAlaxy Evolution and Assembly (gaea) semi-analytic model, that features an improved modelling of the process of cold gas accretion on to supermassive black hole (SMBHs), derived from both analytic arguments and high-resolution simulations. We consider different scenarios for the loss of angular momentum required for the available cold gas to be accreted on to the central SMBHs, and we compare different combinations of triggering mechanisms, including galaxy mergers and disc instabilities in star-forming discs. We compare our predictions with the luminosity function (LF) observed for active galactic nuclei (AGNs) and we confirm that a non-instantaneous accretion time-scale (either in the form of a low-angular momentum reservoir or as an assumed light-curve evolution) is needed in order to reproduce the measured evolution of the AGN-LF and the so-called AGN-downsizing trend. Moreover, we also study the impact of AGN feedback, in the form of AGN-driven outflows, on the SF properties of model galaxies, using prescriptions derived both from empirical studies and from numerical experiments. We show that AGN-driven outflows are effective in suppressing the residual star formation rate in massive galaxies (&gt;1011 M⊙) without changing their overall assembly history. These winds also affect the SFR of lower mass galaxies, resulting in a too large fraction of passive galaxies at &lt;1010 M⊙. Finally, we study the Eddington ratio distribution as a function of SMBH mass, showing that only objects more massive than 108 M⊙ are already in a self-regulated state as inferred from observations.

Host Galaxy Evolution in Radio‐Loud Active Galactic Nuclei

2005 ◽  
Vol 627 (1) ◽  
pp. 97-124 ◽  
Author(s):  
Matthew O’Dowd ◽  
C. Megan Urry
Keyword(s):  
Active Galactic Nuclei ◽  
Galaxy Evolution ◽  
Galactic Nuclei ◽  
Host Galaxy
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