Life-cycles & Energetics of Radio-Loud AGN

2018 ◽  
Vol 14 (S342) ◽  
pp. 122-126
Author(s):  
V. H. Mahatma ◽  
M. J. Hardcastle ◽  
Keyword(s):  
Large Scale ◽  
Cosmic Time ◽  
Mass Function ◽  
Radio Galaxies ◽  
Life Cycles ◽  
Cluster Center ◽  
Qualitative And Quantitative ◽  
Radio Jets ◽  
The Galaxy ◽  
Jet Power

AbstractRadio jets are the large-scale and extragalactic footprints of accretion onto supermassive black holes, and are suggested to be the key ingredient controlling the galaxy stellar mass function. Of particular importance is their jet power - the time-averaged energetic feedback into their environment. Hence, the dynamics, energetics and life-cycles of radio-loud AGN (RLAGN) must be understood in order to build a qualitative and quantitative picture of their impact over cosmic time. Here, we present a study of the spectral age of two powerful, cluster-center radio galaxies, and compare with an analytic model to robustly determine their jet powers. We also present some recent LOFAR observations of the different phases of RLAGN activity, namely the remnant and subsequent restarting phases, which are key to understanding the dynamics of RLAGN over their total lifetime.

scholarly journals Slow-then-rapid quenching as traced by tentative evidence for enhanced metallicities of cluster galaxies at z ∼ 0.2 in the slow quenching phase

2019 ◽  
Vol 621 ◽  
pp. A131 ◽  
Author(s):  
C. Maier ◽  
B. L. Ziegler ◽  
C. P. Haines ◽  
G. P. Smith
Keyword(s):  
Star Formation ◽  
Large Scale ◽  
Rapid Quenching ◽  
Cluster Center ◽  
Cluster Galaxy ◽  
Local Cluster ◽  
Cluster Galaxies ◽  
Star Forming ◽  
The Galaxy ◽  
Tentative Evidence

Aims. As large-scale structures in the Universe develop with time, environmental effects become more and more important as a star formation quenching mechanism. Since the effects of environmental quenching are more pronounced in denser structures that form at later times, we seek to constrain environmental quenching processes using cluster galaxies at z <  0.3. Methods. We explored seven clusters from the Local Cluster Substructure Survey (LoCuSS) at 0.15 <  z <  0.26 with spectra of 1965 cluster members in a mass-complete sample from the ACReS (Arizona Cluster Redshift Survey) Hectospec survey covering a region that corresponds to about three virial radii for each cluster. We measured fluxes of [O II] λ 3727, Hβ, [O III] λ 5007, Hα, and [N II] λ 6584 emission lines of cluster members, enabling us to unambiguously derive O/H gas metallicities. We also measured star formation rates (SFRs) from extinction-corrected Hα fluxes. We compared our cluster galaxy sample with a field sample of 705 galaxies at similar redshifts observed with Hectospec as part of the same survey. Results. We find that star-forming cluster and field galaxies show similar median specific SFRs in a given mass bin of 1 − 3.2 × 1010 M⊙ and 3.2 − 10 × 1010 M⊙, respectively. But their O/H values are displaced, in the lower mass bin, to higher values (significance 2.4σ) at projected radii of R <  R200 compared with galaxies at larger radii and in the field. The comparison with metallicity-SFR-mass model predictions with inflowing gas indicates a slow-quenching scenario in which strangulation is initiated when galaxies pass R ∼ R200 by stopping the inflow of gas. We find tentative evidence that the metallicities of cluster members inside R200 are thereby increasing, but their SFRs are hardly affected for a period of time because these galaxies consume available disk gas. We use the observed fraction of star-forming cluster galaxies as a function of clustercentric radius compared to predictions from the Millennium simulation to constrain quenching timescales to be 1−2 Gyr, which is defined as the time between the moment the galaxy passes R200 until complete quenching of star formation. This is consistent with a slow-then-rapid quenching scenario. Slow quenching (strangulation) starts when the gas inflow is stopped when the galaxy passes R200 with a phase in which cluster galaxies are still star forming, but they show elevated metallicities tracing the ongoing quenching. This phase lasts for 1−2 Gyr, and meanwhile the galaxies travel to denser inner regions of the cluster. This is followed by a “rapid” phase, i.e., a rapid complete quenching of star formation due to the increasing ram pressure toward the cluster center that can also strip the cold gas in massive galaxies.

scholarly journals Scale Free Processes in Galaxy Formation

2015 ◽  
Vol 11 (A29B) ◽  
pp. 696-698
Author(s):  
Nir Mandelker ◽  
Avishai Dekel
Keyword(s):  
Galaxy Formation ◽  
Cosmic Time ◽  
Mass Range ◽  
Mass Function ◽  
De Sitter ◽  
Scale Free ◽  
Normal Galaxies ◽  
The Galaxy ◽  
Self Similar ◽  
Merger Rate

AbstractAccording to the ΛCDM paradigm of cosmology, galaxies form at the centers of dark matter (DM) halos. While galaxy formation involves complex baryonic physics, the formation of DM halos is governed solely by gravity and cosmology. As a result, many of their properties exhibit a near scale-free behaviour, self-similar in either halo mass, cosmic time or both. This is especially true in the Einstein-de Sitter (EdS) regime, valid at redshifts z ≳ 1, when cosmological scaling relations become particularly simple, and in the narrow mass range of normal galaxies, where the fluctuation power spectrum can be approximated by a power law. Since many galaxy properties are strongly correlated with halo mass, they tend to exhibit a self-similar behaviour as well. A partial list of self-similar properties include the mass function of DM halos, the structure of the cosmic web, the accretion/merger rate of matter onto halos, the density profiles of DM halos and their angular momentum, which eventually determines the galaxy structure. We briefly review these below, and comment on how they can be used in conjunction with simple toy models to gain insight into galaxy formation.

scholarly journals On the Environments of Giant Radio Galaxies

2021 ◽  
Author(s):  
Ting-Wen Lan ◽  
J Xavier Prochaska
Keyword(s):  
Large Scale ◽  
Radio Galaxies ◽  
Sloan Digital Sky Survey ◽  
Host Galaxies ◽  
Homogeneous Sample ◽  
Large Scale Structures ◽  
Radio Jets ◽  
Sky Survey ◽  
Scale Structures ◽  
Control Samples

Abstract We test the hypothesis that environments play a key role in enabling the growth of enormous radio structures spanning more than 700 kpc, an extreme population of radio galaxies called giant radio galaxies (GRGs). To achieve this, we explore (1) the relationships between the occurrence of GRGs and the surface number density of surrounding galaxies, including satellite galaxies and galaxies from neighboring halos, as well as (2) the GRG locations towards large-scale structures. The analysis is done by making use of a homogeneous sample of 110 GRGs detected from the LOFAR Two-metre Sky Survey in combination with photometric galaxies from the DESI Legacy Imaging Surveys and a large-scale filament catalog from the Sloan Digital Sky Survey. Our results show that the properties of galaxies around GRGs are similar with that around the two control samples, consisting of galaxies with optical colors and luminosity matched to the properties of the GRG host galaxies. Additionally, the properties of surrounding galaxies depend on neither their relative positions to the radio jet/lobe structures nor the sizes of GRGs. We also find that the locations of GRGs and the control samples with respect to the nearby large-scale structures are consistent with each other. These results demonstrate that there is no correlation between the GRG properties and their environments traced by stars, indicating that external galaxy environments are not the primary cause of the large sizes of the radio structures. Finally, regarding radio feedback, we show that the fraction of blue satellites does not correlate with the GRG properties, suggesting that the current epoch of radio jets have minimal influence on the nature of their surrounding galaxies.

scholarly journals Systematics of Large-Scale Radio Jets

1982 ◽  
Vol 97 ◽  
pp. 121-128 ◽  
Author(s):  
Alan H. Bridle
Keyword(s):  
Large Scale ◽  
Radio Galaxies ◽  
Radio Jets ◽  
Linear Resolution ◽  
Wide Range

Radio jets occur in sources with a wide range of radio luminosities, and in 70% to 80% of nearby radio galaxies. There may be two basic types of large-scale (>1 kpc) jet — B‖-dominated one-sided jets in sources with luminous radio cores, and B⊥-dominated two-sided jets in sources with weak radio cores. The large-scale jets that have been observed at high linear resolution are well collimated within a few kpc of their cores, then flare and recollimate further out. Their brightness-radius evolution is often “subadiabatic”.

scholarly journals How to add massive neutrinos to your ΛCDM simulation – extending cosmology rescaling algorithms

2019 ◽  
Vol 489 (4) ◽  
pp. 5938-5951 ◽  
Author(s):  
Matteo Zennaro ◽  
Raúl E Angulo ◽  
Giovanni Aricò ◽  
Sergio Contreras ◽  
Marcos Pellejero-Ibáñez
Keyword(s):  
Large Scale ◽  
Evolution Equations ◽  
Linear Structure ◽  
Mass Function ◽  
Arbitrary Mass ◽  
The Galaxy ◽  
Point Correlation ◽  
Point Correlation Function ◽  
Cent Level ◽  
Massive Neutrinos

ABSTRACT Providing accurate predictions for the spatial distribution of matter and luminous tracers in the presence of massive neutrinos is an important task, given the imminent arrival of highly accurate large-scale structure observations. In this work, we address this challenge by extending cosmology-rescaling algorithms to massive neutrino cosmologies. In this way, a ΛCDM simulation can be modified to provide non-linear structure formation predictions in the presence of a hot component of arbitrary mass, and, if desired, to include non-gravitational modifications to the clustering of matter on large scales. We test the accuracy of the method by comparing its predictions to a suite of simulations carried out explicitly including a neutrino component in its evolution equations. We find that, for neutrino masses in the range Mν ∈ [0.06, 0.3] eV the matter power spectrum is recovered to better than $1{{\ \rm per\ cent}}$ on all scales k < 2 h Mpc−1. Similarly, the halo mass function is predicted at a few per cent level over the range Mhalo ∈ [1012, 1015] h−1 M⊙, and so do also the multipoles of the galaxy two-point correlation function in redshift space over r ∈ [0.1, 200] h−1 Mpc. We provide parametric forms for the necessary transformations, as a function of Ωm and Ων for various target redshifts.

scholarly journals Large-scale environment of FR 0 radio galaxies

2020 ◽  
Vol 633 ◽  
pp. A161 ◽  
Author(s):  
A. Capetti ◽  
F. Massaro ◽  
R. D. Baldi
Keyword(s):  
Radio Emission ◽  
Large Scale ◽  
Large Fraction ◽  
Radio Galaxies ◽  
Radio Sources ◽  
Early Type ◽  
Extended Radio ◽  
Significant Difference ◽  
Two Populations ◽  
Jet Power

We explore the properties of the large-scale environment of the sources in the Faranoff-Riley class 0 catalog (FR0CAT). This sample includes 104 compact radio sources that are associated with nearby (z <  0.05) early-type galaxies. Using various estimators, we find that FR 0s are located in regions with higher than the average number of galaxies. The average galaxies density around FR 0s is a factor two lower with respect to FR I radio galaxies. This latter difference is driven by the large fraction (63%) of FR 0s that are located in groups formed by fewer than 15 galaxies. FR Is rarely (17%) inhabit an environment like this. In addition to the lack of substantial extended radio emission that defines the FR 0 class, this is the first significant difference between the properties of these two populations of low-power radio galaxies. We interpret the differences in environment between FR 0s and FR Is as due to an evolutionary link between local galaxies density, black hole spin, jet power, and extended radio emission.

scholarly journals Large-Scale Radio Jets

1983 ◽  
Vol 6 ◽  
pp. 731-733
Author(s):  
R.A. Laing
Keyword(s):  
Surface Brightness ◽  
Large Scale ◽  
Spiral Galaxies ◽  
Radio Galaxies ◽  
Brightness Distribution ◽  
Physical Parameters ◽  
Radio Brightness ◽  
Radio Jets ◽  
Radio Brightness Distribution

The purpose of this review is to outline the systematic properties of radio jets on kpc scales, as derived from the basic observations of surface brightness and linear polarization and to emphasize the uncertainties in the determination of their physical parameters. These results come primarily from observations of about 100 jets with the VLA: a fuller account is given by Bridle (1982) and the proceedings of IAU Symposium 97 contain many illustrations and references, which must be omitted here.I take a “jet” to be a feature in the radio brightness distribution which is at least four times as long as it is wide, which can be clearly separated (spatially or by brightness contrast) from the rest of the source and points away from a radio core. Wilson (1982) has considered jets in spiral galaxies and I shall discuss only the more luminous jets found in elliptical radio galaxies and quasars.

scholarly journals Taking snapshots of the jet-ISM interplay with ALMA

2020 ◽  
Vol 15 (S359) ◽  
pp. 243-248
Author(s):  
Raffaella Morganti ◽  
Tom Oosterloo ◽  
Clive N. Tadhunter
Keyword(s):  
Large Scale ◽  
Radio Galaxies ◽  
Plasma Jets ◽  
Molecular Gas ◽  
Radio Jets ◽  
Evolutionary Phase ◽  
Outflow Rate ◽  
Mass Outflow ◽  
Low Mass ◽  
The Impact

AbstractWe present an update of our ongoing project to characterise the impact of radio jets on the interstellar medium (ISM). This is done by tracing the distribution, kinematics and excitation of the molecular gas at high spatial resolution using ALMA. The radio active galactic nuclei (AGN) studied are in the interesting phase of having a recently born radio jet. In this stage, the plasma jets can have the largest impact on the ISM, as also predicted by state-of-the-art simulations. The two targets we present have quite different ages, allowing us to get snapshots of the effects of radio jets as they grow and evolve. Interestingly, both also host powerful quasar emission, making them ideal for studying the full impact of AGN. The largest mass outflow rate of molecular gas is found in a radio galaxy () hosting a newly born radio jet still in the early phase of emerging from an obscuring cocoon of gas and dust. Although the molecular mass outflow rate is high (few hundred), the outflow is limited to the inner few hundred pc region. In a second object (), the jet is larger (a few kpc) and is in a more advanced evolutionary phase. In this object, the distribution of the molecular gas is reminiscent of what is seen, on larger scales, in cool-core clusters hosting radio galaxies. Interestingly, gas deviating from quiescent kinematics (possibly indicating an outflow) is not very prominent, limited only to the very inner region, and has a low mass outflow rate. Instead, on kpc scales, the radio lobes appear associated with depressions in the distribution of the molecular gas. This suggests that the lobes have broken out from the dense nuclear region. However, the AGN does not appear to be able, at present, to stop the star formation observed in this galaxy. These results support the idea that the effects of the radio source start in the very first phases by producing outflows which, however, tend to be limited to the kpc region. After that, the effects turn into producing large-scale bubbles which could, in the long term, prevent the surrounding gas from cooling. Thus, our results provide a way to characterise the effect of radio jets in different phases of their evolution and in different environments, bridging the studies done for radio galaxies in clusters.

A panchromatic spatially resolved study of the inner 500 pc of NGC 1052

2019 ◽  
Vol 15 (S359) ◽  
pp. 427-428
Author(s):  
Luis G. Dahmer-Hahn ◽  
Rogério Riffel ◽  
Tiago V. Ricci ◽  
João E. Steiner ◽  
Thaisa Storchi-Bergmann ◽  
...  
Keyword(s):  
Large Scale ◽  
Near Infrared ◽  
Elliptical Galaxy ◽  
Population Analysis ◽  
Optical Data ◽  
Radio Jets ◽  
Spatially Resolved ◽  
Integral Field Spectroscopy ◽  
The Galaxy ◽  
Integral Field

AbstractWe analyzed the inner 320 × 535 pc2 of the elliptical galaxy NGC 1052 with integral field spectroscopy, both in the optical and in the near-infrared (NIR). The stellar population analysis revealed a dominance of old stellar populations from the optical data, and an intermediate-age ring from NIR data. When combining optical+NIR data, optical results were favoured. The emission-line analysis revealed five kinematic components, where two of them are unresolved and probably associated with the active galactic nucleus (AGN), one is associated with large-scale shocks, one with the radio jets, and the last could be explained by either a bipolar outflow, rotation in an eccentric disc or a combination of a disc and large-scale gas bubbles. Our results also indicate that the emission within the galaxy is caused by a combination of shocks and photoionization by the AGN.

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