The cluster environments of radio-loud AGN

AbstractRadio-loud AGN play an important rôle in galaxy evolution. We need to understand their properties, and the processes that affect their behaviour in order to model galaxy formation and development. We here present preliminary results of an investigation into the cluster environments of radio galaxies. We have found evidence of a strong correlation between radio luminosity and environment richness for low excitation radio galaxies, and no evidence of evolution of the environment with redshift. Conversely, for high excitation radio galaxies, we found no correlation with environment richness, and tentative evidence of evolution of the cluster environment.

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The XXL Survey

Astronomy and Astrophysics ◽

10.1051/0004-6361/201834581 ◽

2019 ◽

Vol 625 ◽

pp. A111 ◽

Cited By ~ 2

Author(s):

Andrew Butler ◽

Minh Huynh ◽

Anna Kapińska ◽

Ivan Delvecchio ◽

Vernesa Smolčić ◽

...

Keyword(s):

Galaxy Evolution ◽

High Redshift ◽

Radio Galaxies ◽

Optical Data ◽

Scaling Relation ◽

Radio Luminosity ◽

Hot Gas ◽

Luminosity Functions ◽

Wide Range ◽

Luminosity Evolution

The evolution of the comoving kinetic luminosity densities (Ωkin) of the radio loud high-excitation radio galaxies (RL HERGs) and the low-excitation radio galaxies (LERGs) in the ultimate XMM extragalactic survey south (XXL-S) field is presented. The wide area and deep radio and optical data of XXL-S have allowed the construction of the radio luminosity functions (RLFs) of the RL HERGs and LERGs across a wide range in radio luminosity out to high redshift (z = 1.3). The LERG RLFs display weak evolution: Φ(z)∝(1 + z)0.67 ± 0.17 in the pure density evolution (PDE) case and Φ(z)∝(1 + z)0.84 ± 0.31 in the pure luminosity evolution (PLE) case. The RL HERG RLFs demonstrate stronger evolution than the LERGs: Φ(z)∝(1 + z)1.81 ± 0.15 for PDE and Φ(z)∝(1 + z)3.19 ± 0.29 for PLE. Using a scaling relation to convert the 1.4 GHz radio luminosities into kinetic luminosities, the evolution of Ωkin was calculated for the RL HERGs and LERGs and compared to the predictions from various simulations. The prediction for the evolution of radio mode feedback in the Semi-Analytic Galaxy Evolution (SAGE) model is consistent with the Ωkin evolution for all XXL-S RL AGN (all RL HERGs and LERGs), indicating that the kinetic luminosities of RL AGN may be able to balance the radiative cooling of the hot phase of the IGM. Simulations that predict the Ωkin evolution of LERG equivalent populations show similar slopes to the XXL-S LERG evolution, suggesting that observations of LERGs are well described by models of SMBHs that slowly accrete hot gas. On the other hand, models of RL HERG equivalent populations differ in their predictions. While LERGs dominate the kinetic luminosity output of RL AGN at all redshifts, the evolution of the RL HERGs in XXL-S is weaker compared to what other studies have found. This implies that radio mode feedback from RL HERGs is more prominent at lower redshifts than was previously thought.

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Understanding mechanical feedback from HERGs and LERGs

Proceedings of the International Astronomical Union ◽

10.1017/s1743921319003521 ◽

2018 ◽

Vol 14 (A30) ◽

pp. 86-89

Author(s):

Imogen H. Whittam

Keyword(s):

Galaxy Evolution ◽

Stellar Populations ◽

Radio Galaxies ◽

High Excitation ◽

Host Galaxies ◽

Radio Jets ◽

Accretion Rates ◽

Hydrodynamical Simulations ◽

Mechanical Feedback

AbstractThe properties of ∼ 1000 high-excitation and low-excitation radio galaxies (HERGs and LERGs) selected from the Heywood et al. (2016) 1 – 2 GHz VLA survey of Stripe 82 are investigated. The HERGs in this sample are generally found in host galaxies with younger stellar populations than LERGs, consistent with other work. The HERGs tend to accrete at a faster rate than the LERGs, but there is more overlap in the accretion rates of the two classes than has been found previously. We find evidence that mechanical feedback may be significantly underestimated in hydrodynamical simulations of galaxy evolution; 84 % of this sample release more than 10 % of their energy in mechanical form. Mechanical feedback is significant for many of the HERGs in this sample as well as the LERGs; nearly 50 % of the HERGs release more than 10 % of their energy in their radio jets.

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Quasi-equilibrium models of high-redshift disc galaxy evolution

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3451 ◽

2020 ◽

Vol 500 (3) ◽

pp. 3394-3412

Author(s):

Steven R Furlanetto

Keyword(s):

Star Formation ◽

Galaxy Evolution ◽

Galaxy Formation ◽

High Redshift ◽

Formation Rate ◽

New Physics ◽

Small Scale ◽

Quasi Equilibrium ◽

Mass Relation ◽

Disc Galaxy

ABSTRACT In recent years, simple models of galaxy formation have been shown to provide reasonably good matches to available data on high-redshift luminosity functions. However, these prescriptions are primarily phenomenological, with only crude connections to the physics of galaxy evolution. Here, we introduce a set of galaxy models that are based on a simple physical framework but incorporate more sophisticated models of feedback, star formation, and other processes. We apply these models to the high-redshift regime, showing that most of the generic predictions of the simplest models remain valid. In particular, the stellar mass–halo mass relation depends almost entirely on the physics of feedback (and is thus independent of the details of small-scale star formation) and the specific star formation rate is a simple multiple of the cosmological accretion rate. We also show that, in contrast, the galaxy’s gas mass is sensitive to the physics of star formation, although the inclusion of feedback-driven star formation laws significantly changes the naive expectations. While these models are far from detailed enough to describe every aspect of galaxy formation, they inform our understanding of galaxy formation by illustrating several generic aspects of that process, and they provide a physically grounded basis for extrapolating predictions to faint galaxies and high redshifts currently out of reach of observations. If observations show violations from these simple trends, they would indicate new physics occurring inside the earliest generations of galaxies.

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First Light And Reionization Epoch Simulations (FLARES) – I. Environmental dependence of high-redshift galaxy evolution

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3360 ◽

2020 ◽

Vol 500 (2) ◽

pp. 2127-2145

Author(s):

Christopher C Lovell ◽

Aswin P Vijayan ◽

Peter A Thomas ◽

Stephen M Wilkins ◽

David J Barnes ◽

...

Keyword(s):

Galaxy Evolution ◽

Galaxy Formation ◽

Dynamic Range ◽

High Redshift ◽

Formation Rate ◽

Mass Function ◽

Distribution Functions ◽

Large Area ◽

Composite Distribution ◽

Environmental Dependence

ABSTRACT We introduce the First Light And Reionisation Epoch Simulations (FLARES), a suite of zoom simulations using the EAGLE model. We resimulate a range of overdensities during the Epoch of Reionization (EoR) in order to build composite distribution functions, as well as explore the environmental dependence of galaxy formation and evolution during this critical period of galaxy assembly. The regions are selected from a large $(3.2 \, \mathrm{cGpc})^{3}$ parent volume, based on their overdensity within a sphere of radius 14 h−1 cMpc. We then resimulate with full hydrodynamics, and employ a novel weighting scheme that allows the construction of composite distribution functions that are representative of the full parent volume. This significantly extends the dynamic range compared to smaller volume periodic simulations. We present an analysis of the galaxy stellar mass function (GSMF), the star formation rate distribution function (SFRF), and the star-forming sequence (SFS) predicted by FLARES, and compare to a number of observational and model constraints. We also analyse the environmental dependence over an unprecedented range of overdensity. Both the GSMF and the SFRF exhibit a clear double-Schechter form, up to the highest redshifts (z = 10). We also find no environmental dependence of the SFS normalization. The increased dynamic range probed by FLARES will allow us to make predictions for a number of large area surveys that will probe the EoR in coming years, carried out on new observatories such as Roman and Euclid.

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In pursuit of giants

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038405 ◽

2020 ◽

Vol 644 ◽

pp. A144

Author(s):

D. Donevski ◽

A. Lapi ◽

K. Małek ◽

D. Liu ◽

C. Gómez-Guijarro ◽

...

Keyword(s):

Star Formation ◽

Galaxy Evolution ◽

Galaxy Formation ◽

Main Sequence ◽

Stellar Mass ◽

Starburst Galaxies ◽

Analytical Models ◽

Physical Parameters ◽

Star Forming ◽

Galaxy Populations

The dust-to-stellar mass ratio (Mdust/M⋆) is a crucial, albeit poorly constrained, parameter for improving our understanding of the complex physical processes involved in the production of dust, metals, and stars in galaxy evolution. In this work, we explore trends of Mdust/M⋆ with different physical parameters and using observations of 300 massive dusty star-forming galaxies detected with ALMA up to z ≈ 5. Additionally, we interpret our findings with different models of dusty galaxy formation. We find that Mdust/M⋆ evolves with redshift, stellar mass, specific star formation rates, and integrated dust size, but that evolution is different for main-sequence galaxies than it is for starburst galaxies. In both galaxy populations, Mdust/M⋆ increases until z ∼ 2, followed by a roughly flat trend towards higher redshifts, suggesting efficient dust growth in the distant universe. We confirm that the inverse relation between Mdust/M⋆ and M⋆ holds up to z ≈ 5 and can be interpreted as an evolutionary transition from early to late starburst phases. We demonstrate that the Mdust/M⋆ in starbursts reflects the increase in molecular gas fraction with redshift and attains the highest values for sources with the most compact dusty star formation. State-of-the-art cosmological simulations that include self-consistent dust growth have the capacity to broadly reproduce the evolution of Mdust/M⋆ in main-sequence galaxies, but underestimating it in starbursts. The latter is found to be linked to lower gas-phase metallicities and longer dust-growth timescales relative to observations. The results of phenomenological models based on the main-sequence and starburst dichotomy as well as analytical models that include recipes for rapid metal enrichment are consistent with our observations. Therefore, our results strongly suggest that high Mdust/M⋆ is due to rapid dust grain growth in the metal-enriched interstellar medium. This work highlights the multi-fold benefits of using Mdust/M⋆ as a diagnostic tool for: (1) disentangling main-sequence and starburst galaxies up to z ∼ 5; (2) probing the evolutionary phase of massive objects; and (3) refining the treatment of the dust life cycle in simulations.

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RC J0311+0507: A Candidate to Superpowerful Radio Galaxies with z = 4.514

Proceedings of the International Astronomical Union ◽

10.1017/s1743921306010581 ◽

2006 ◽

Vol 2 (S235) ◽

pp. 431-431

Author(s):

A. I. Kopylov ◽

Yu. N. Parijskij ◽

N. S. Soboleva ◽

A. V. Temirova ◽

O. V. Verkhodanov ◽

...

Keyword(s):

Radio Source ◽

Radio Galaxies ◽

Strong Line ◽

Radio Luminosity ◽

Spectrum Radio

AbstractThe investigations of the ultra steep spectrum radio source RC J0311+0507 (4C+04.11) in radio (RATAN-600, VLA) and optics (6-m telescope SAO RAS) are presented. The identification of a strong line at 6703 Å with Lyα gives a redshift z=4.514. The object belongs to the group of extremely distant radio galaxies of ultrahigh radio luminosity (P1400 = 1.3 × 1029WHz−1).

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Dark-ages reionization and galaxy formation simulation – XVII. Sizes, angular momenta, and morphologies of high-redshift galaxies

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1810 ◽

2019 ◽

Vol 488 (2) ◽

pp. 1941-1959 ◽

Cited By ~ 2

Author(s):

Madeline A Marshall ◽

Simon J Mutch ◽

Yuxiang Qin ◽

Gregory B Poole ◽

J Stuart B Wyithe

Keyword(s):

Angular Momentum ◽

Galaxy Evolution ◽

Galaxy Formation ◽

High Redshift ◽

Stellar Mass ◽

Galaxy Mergers ◽

High Redshift Galaxies ◽

Massive Galaxies ◽

Angular Momenta ◽

Redshift Galaxies

Abstract We study the sizes, angular momenta, and morphologies of high-redshift galaxies, using an update of the meraxes semi-analytic galaxy evolution model. Our model successfully reproduces a range of observations from redshifts z = 0–10. We find that the effective radius of a galaxy disc scales with ultraviolet (UV) luminosity as $R_\mathrm{ e}\propto L_{\textrm{UV}}^{0.33}$ at z = 5–10, and with stellar mass as $R_e\propto M_\ast ^{0.24}$ at z = 5 but with a slope that increases at higher redshifts. Our model predicts that the median galaxy size scales with redshift as Re ∝ (1 + z)−m, where m = 1.98 ± 0.07 for galaxies with (0.3–1)$L^\ast _{z=3}$ and m = 2.15 ± 0.05 for galaxies with (0.12–0.3)$L^\ast _{z=3}$. We find that the ratio between stellar and halo specific angular momentum is typically less than 1 and decreases with halo and stellar mass. This relation shows no redshift dependence, while the relation between specific angular momentum and stellar mass decreases by ∼0.5 dex from z = 7 to z = 2. Our model reproduces the distribution of local galaxy morphologies, with bulges formed predominantly through galaxy mergers for low-mass galaxies, disc-instabilities for galaxies with M* ≃ 1010–$10^{11.5}\, \mathrm{M}_\odot$, and major mergers for the most massive galaxies. At high redshifts, we find galaxy morphologies that are predominantly bulge-dominated.

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Stellar Population Models of Distant Radio Galaxies

Symposium - International Astronomical Union ◽

10.1017/s0074180900081948 ◽

1996 ◽

Vol 175 ◽

pp. 588-590

Author(s):

D. Villani ◽

S. Di Serego Alighieri

Keyword(s):

Energy Distribution ◽

Galaxy Formation ◽

Stellar Population ◽

Spectral Energy Distribution ◽

Formation Rate ◽

Stellar Populations ◽

Radio Galaxies ◽

Initial Mass Function ◽

Spectral Energy ◽

The Galaxy

Stellar populations of high redshift radio galaxies (HzRG) (z up to 4.2) are the oldest stellar systems known, that is the ones formed at the earliest cosmological epochs. Therefore they are the best objects for providing us with information about the epoch of galaxy formation. The information on the stellar populations in HzRG are obtained from the study of their Integrated Spectral Energy Distribution (ISED) which are gathered both from spectra and integrated magnitudes. The most common approach for the interpretation of colors and spectral features of the energy distribution of galaxies is the Evolutionary Population Synthesis (EPS), which has been introduced for the first time by Tinsley in 1972. EPS models have often been used in the past to interpret the ISED of HzRG (Chambers & Charlot 1990; Lilly & Longair 1984; di Serego Alighieri et al. 1994) in order to draw conclusions on the age of the stellar populations and therefore on the epoch of galaxy formation. The results are sometimes conflicting and a number of very recent EPS models have become available (Bressan et al. 1995; Bruzual & Charlot 1993; Buzzoni 1989; Guiderdoni & Rocca-Volmerange 1987): we are therefore analysing the differences between the various EPS models with the aim of assessing their suitability to study the stellar population at early epochs. The EPS models assume for stars a given Initial Mass Function(IMF) as well as a Star Formation Rate (SFR). Then one can compute the number of stars with given mass present in the galaxy as a function of time. The position of each star in the HR diagram is determined by means of the isochrones, which are calculated from stellar evolutionary models. The ISED of a galaxy is obtained from the superposition of the spectra of single stars obtained from a stellar spectral library. Thus these models describe the galaxy ISED as a function of the time, giving a complete evolutionary picture.

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ERQs are the BOSS of quasar samples: the highest velocity [O iii] quasar outflows

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1993 ◽

2019 ◽

Vol 488 (3) ◽

pp. 4126-4148 ◽

Cited By ~ 14

Author(s):

S Perrotta ◽

F Hamann ◽

N L Zakamska ◽

R M Alexandroff ◽

D Rupke ◽

...

Keyword(s):

Galaxy Evolution ◽

Strong Correlation ◽

Rest Frame ◽

Optical Spectra ◽

Emission Lines ◽

Host Galaxies ◽

Bolometric Luminosity ◽

Near Ir

ABSTRACT We investigate extremely red quasars (ERQs), a remarkable population of heavily reddened quasars at redshift z ∼ 2−3 that might be caught during a short-lived ‘blow-out’ phase of quasar/galaxy evolution. We perform a near-IR observational campaign using Keck/NIRSPEC, VLT/X-shooter, and Gemini/GNIRS to measure rest-frame optical spectra of 28 ERQs with median infrared luminosity 〈log L(erg s−1)〉 ∼ 46.2. They exhibit the broadest and most blueshifted [O iii] λ4959,5007 emission lines ever reported, with widths (w90) ranging between 2053 and 7227 km s−1, and maximum outflow speeds (v98) up to 6702 km s−1. ERQs on average have [O iii] outflows velocities about three times larger than those of luminosity-matched blue quasar samples. This discrepancy can be explained by a strong correlation between [O iii] kinematics and i–W3 colour, and not by radio loudness, or higher Eddington ratios. We estimate for these objects that at least 3–5 per cent of their bolometric luminosity is being converted into the kinetic power of the observed wind. Our results reveal that ERQs have the potential to strongly affect the evolution of host galaxies.

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