scholarly journals The XXL Survey

2019 ◽  
Vol 625 ◽  
pp. A111 ◽  
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.

Modeling galaxy evolution at high-redshift in highly overdense and normal regions

2019 ◽  
Vol 15 (S341) ◽  
pp. 299-301
Author(s):  
Raphael Sadoun ◽  
Emilio Romano-Daz ◽  
Isaac Shlosman ◽  
Zheng Zheng
Keyword(s):  
Monte Carlo ◽  
High Resolution ◽  
Galaxy Evolution ◽  
Equivalent Width ◽  
High Redshift ◽  
Post Processing ◽  
High Redshift Galaxies ◽  
Massive Galaxies ◽  
Luminosity Functions ◽  
Galactic Outflows

AbstractWe present results from high-resolution, zoom-in cosmological simulations to study the effect of feedback from galactic outflows on the physical and Lyα properties of high-redshift galaxies in highly overdense and normal environments at z >∼6. The Lyα properties have been obtained by post-processing the simulations with a Monte-Carlo radiative transfer (RT) code. Our results demonstrate that galactic outflows play an important role in regulating the growth of massive galaxies in overdense regions as well as the temperature and metallicity of the intergalactic medium. In particular, we find that galactic outflows are necessary to reproduce the observed Lyα luminosity functions as well as the apparent Lyα luminosity, line width and equivalent width distributions of luminous Lyα emitters at z ∼ 6.

scholarly journals GAMA/WiggleZ: the 1.4 GHz radio luminosity functions of high- and low-excitation radio galaxies and their redshift evolution toz= 0.75

2016 ◽  
Vol 460 (1) ◽  
pp. 2-17 ◽  
Author(s):  
Michael B. Pracy ◽  
John H. Y. Ching ◽  
Elaine M. Sadler ◽  
Scott M. Croom ◽  
I. K. Baldry ◽  
...  
Keyword(s):  
Radio Galaxies ◽  
Radio Luminosity ◽  
Luminosity Functions

scholarly journals Overdensity of SMGs in fields containing z ∼ 0.3 galaxies: magnification bias and the implications for studies of galaxy evolution

2020 ◽  
Vol 498 (4) ◽  
pp. 4635-4649
Author(s):  
L Dunne ◽  
L Bonavera ◽  
J Gonzalez-Nuevo ◽  
S J Maddox ◽  
C Vlahakis
Keyword(s):  
Galaxy Evolution ◽  
Cross Correlation ◽  
High Redshift ◽  
Spectral Energy ◽  
Complete Sample ◽  
Energy Distributions ◽  
Statistical Measures ◽  
Luminosity Functions ◽  
Significant Contamination ◽  
The Impact

ABSTRACT We report a remarkable overdensity of high-redshift submillimetre galaxies (SMG), 4–7 times the background, around a statistically complete sample of twelve 250 μm selected galaxies at z = 0.35, which were targeted by ALMA in a study of gas tracers. This overdensity is consistent with the effect of lensing by the haloes hosting the target z = 0.35 galaxies. The angular cross-correlation in this sample is consistent with statistical measures of this effect made using larger sub-mm samples. The magnitude of the overdensity as a function of radial separation is consistent with intermediate scale lensing by haloes of the order of $7\times 10^{13}\mbox{ $\rm M_{\odot }$ }$, which should host one or possibly two bright galaxies and several smaller satellites. This is supported by observational evidence of interaction with satellites in four out of the six fields with SMG, and membership of a spectroscopically defined group for a fifth. We also investigate the impact of these SMG on the reported Herschel fluxes of the z = 0.35 galaxies, as they produce significant contamination in the 350 and 500 μm Herschel bands. The higher than random incidence of these boosting events implies a significantly larger bias in the sub-mm colours of Herschel sources associated with z < 0.7 galaxies than has previously been assumed, with fboost = 1.13, 1.26, 1.44 at 250, 350, and 500 μm . This could have implications for studies of spectral energy distributions, source counts, and luminosity functions based on Herschel samples at z = 0.2–0.7.

scholarly journals KECK Spectropolarimetry of High Redshift Radio Galaxies

1996 ◽  
Vol 175 ◽  
pp. 402-404
Author(s):  
A. Cimatti ◽  
A. Dey ◽  
W. Van BREUGEL ◽  
R. Antonucci ◽  
H. Spinrad
Keyword(s):  
Galaxy Evolution ◽  
High Redshift ◽  
Radio Galaxies ◽  
Unified Model ◽  
Powerful Radio ◽  
Imaging Spectrometer ◽  
Alignment Effect ◽  
Stellar Radiation ◽  
Resolution Imaging ◽  
To Come

High redshift radio galaxies (HzRGs) are observable up to cosmological distances competitive with the most distant quasars. However, before using them as probes of galaxy evolution, it is crucial to separate the stellar and non-stellar components. One of the most striking properties of HzRGs is the alignment of the UV continuum with the axis of the radio source (alignment effect; McCarthy et al. 1987). However, the relative importance of the stellar and non-stellar radiation to the alignment effect is still unknown, although a significant fraction is recognized to come from scattering of anisotropic radiation emitted by the obscured nucleus, as expected in the unified model of powerful radio sources (di Serego Alighieri, Cimatti & Fosbury 1994). Spectropolarimetry is the most powerful technique to observe at the same time different radiation components, but the 4m class telescopes can reach a sufficient S/N ratio only on the few brightest objects. Therefore, in order to investigate the origin of the alignment effect and to test the validity of the unified model of powerful radio-loud AGN, we have started a program of optical spectropolarimetry of HzRGs with the W.M. Keck 10m telescope equipped with the Low Resolution Imaging Spectrometer (LRIS) in polarimetric mode.

Revealing AGN, young and old stellar populations in HzRGs with PEGASE.3

2013 ◽  
Vol 9 (S304) ◽  
pp. 307-310
Author(s):  
Guillaume Drouart ◽  
Carlos De Breuck ◽  
Joël Vernet ◽  
Brigitte Rocca Volmerange ◽  
Nicholas Seymour
Keyword(s):  
Galaxy Evolution ◽  
Stellar Population ◽  
Radio Galaxy ◽  
High Redshift ◽  
Radio Galaxies ◽  
Host Galaxies ◽  
Continuous Coverage ◽  
Near Ir ◽  
The Relationship ◽  
Very High

AbstractThe HeRGÉ (Herschel Radio Galaxy Evolution) project consists of a sample of 70 radio galaxies in the range 1 < z < 5.2. They benefit from continuous coverage from 3 to 870μm with Spitzer, Herschel and sub-mm ground-based instruments (SCUBA, LABOCA). As a calorimeter, IR is an excellent proxy to estimate the contribution of both AGN and starburst, making of radio galaxies perfect candidates to provide new insights into the relationship between AGN and their host galaxies. The IR SED fitting with empirical templates reveals that radio galaxies are luminous and that their black holes and their host galaxies are not growing simultaneously. Extending the SED to optical/near-IR on a subsample of 12 radio galaxies spanning 1 < z < 4 reveal the necessity of three components to reproduce the observations. Making use of the evolutionary code PEGASE.3 and an AGN torus model, we are able to estimate parameters from the AGN torus, the evolved stellar population and the starburst (SB). They reveal that radio galaxies are massive, evolved, forming the bulk of their mass at very high redshift in a short timescale, but experience episodic, strong SB events, often associated with an AGN activity.

scholarly journals Interaction of the Beams of Active Galactic Nuclei with Their Environment at High Redshifts

1989 ◽  
Vol 134 ◽  
pp. 469-471
Author(s):  
Gopal-Krishna ◽  
P. J. Wiita
Keyword(s):  
Elliptical Galaxy ◽  
High Redshift ◽  
Radio Galaxies ◽  
Beam Power ◽  
Opening Angle ◽  
Log P ◽  
Radio Luminosity ◽  
Microwave Background ◽  
Inverse Compton ◽  
Mean Size

Aiming at a physical interpretation of the cosmological evolution of radio galaxies, we extend to a high redshift our analytical model for the propagation of relativistic beams first through a hot gaseous halo of the parent elliptical galaxy and then through an even hotter, but less dense, diffuse IGM, after crossing a pressure-matched interface between the two media1–5. This model, verified by quasi-hydrodynamical numerical simulations5 has earlier explained: (1) the current mean size of classical double radio sources (D ∼350 kpc), (2) their steep linear-size evolution with redshift, z: D α (1+z)−3, (3). The correlation between size and radio luminosity (at fixed z): D α P0.3, (4) the number and <P> of giant radio galaxies, and (5) the break in the local radio luminosity function (LRLF), occurring near P ∼1024W.Hz−1 at 1 GHz (Ho = 50 kms−1 Mpc−1). Inputs to the model are observationally based average parameters of the halo1 {kTh∼1 keV, n(r) ∼10−2cm−3[1+(r/2kpc)2]−3/4}, IGM7 {kTIGM ∼18 keV (1+z)2, nIGM ∼7.10−7cm−3(1+z)3} and the beam4 {opening angle θ (radian) = 0.02 + 0.03 [29 - log P(t=0)]}. We assume a reasonable value of ∊ = 0.1 for the initial efficiency of conversion of the beam power, Lb (Watts) into (total) radio output Pt ∼1010. P(W.Hz−1). A gradual weakening of magnetic field within the expanding source raises the significance of inverse Compton losses against the Cosmic Microwave Background (CMB), leading to a reduced radio efficiency (RRE)3,2.

scholarly journals High-redshift radio galaxies: the most massive galaxies at every epoch

2006 ◽  
Vol 2 (14) ◽  
pp. 382-383
Author(s):  
Carlos De Breuck
Keyword(s):  
Galaxy Evolution ◽  
High Redshift ◽  
Low Frequency ◽  
Radio Galaxies ◽  
Host Galaxies ◽  
Space Density ◽  
Massive Galaxies

AbstractRadio galaxies are identified with the most massive host galaxies known out to z = 5 and can put strong constraints on galaxy evolution models, provided their space density is accurately determined. Here, I present the important role low-frequency radio surveys will have in this by selecting the highest redshift radio galaxies using the steepness of their radio spectra.

scholarly journals The Stellar Mass Distribution of Powerful Radio Galaxies Across 1 < z < 5.2

2006 ◽  
Vol 2 (S235) ◽  
pp. 427-427
Author(s):  
Nick Seymour ◽  
D. Stern ◽  
C. De Breuck ◽  
Keyword(s):  
Rest Frame ◽  
High Redshift ◽  
Color Space ◽  
Radio Galaxies ◽  
Stellar Mass ◽  
Energy Output ◽  
Host Galaxy ◽  
Spectral Energy ◽  
Radio Luminosity ◽  
Powerful Radio

AbstractWe present the results of a comprehensive Spitzer survey of 70 radio galaxies across 1 < z < 5.2. Using IRAC (3.6–8.0μm), IRS (16 μm) and MIPS (24–160 μm) imaging, we decompose the rest-frame optical to infrared spectral energy distributions into stellar, AGN, and dust components and determine the contribution of host galaxy stellar emission at rest-frame 1.6 μm (H-band). We find that the fraction of emitted light at rest-frame 1.6 μm from stars is >80% for over half the high redshift radio galaxies. The other radio galaxies have 1.6 μm stellar fractions spanning the range 20–80%. The resultant stellar luminosities imply stellar masses of 1011−12M⊙, independent of redshift, indicating that radio galaxies are amoungst the most massive galaxies observed over this redshift range. Powerful radio galaxies tend to lie in a similar region of mid-IR color-color space as unobscured AGN, despite the inferred stellar contribution to their shorter-wavelength, mid-IR SEDs. The stellar fraction of the rest-frame 1.6 μm luminosity has no correlation with redshift, radio luminosity, or rest-frame mid-IR (5 μm) luminosity. The bolometric energy output of these sources is dominated by the infrared, and the mid-IR luminosities are found to be similar to that of lower redshift (z < 1) radio galaxies. As expected, these exceptionally high mid-IR luminosities are consistent with an obscured, highly-accreting AGN. A weak, but significant, correlation of stellar mass with radio luminosity is found, consistent with earlier results.

scholarly journals The cluster environments of radio-loud AGN

2014 ◽  
Vol 10 (S313) ◽  
pp. 299-300
Author(s):  
Judith Ineson ◽  
Judith Croston ◽  
Martin Hardcastle ◽  
Ralph Kraft ◽  
Daniel Evans ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
Galaxy Formation ◽  
Strong Correlation ◽  
Radio Galaxies ◽  
High Excitation ◽  
Radio Luminosity ◽  
Preliminary Results ◽  
Model Galaxy ◽  
Cluster Environment ◽  
Tentative Evidence

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.

scholarly journals The Tully-Fisher Relation as a Function of Redshift: Disentangling Galaxy Evolution and Selection Biases

2006 ◽  
Vol 2 (S235) ◽  
pp. 3-7
Author(s):  
Nicole P. Vogt
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Galaxy Formation ◽  
Surface Brightness ◽  
Velocity Structure ◽  
High Redshift ◽  
Selection Effects ◽  
Groups Of Galaxies ◽  
Wide Range ◽  
Fisher Relation

AbstractWe review the status of current observations of the fundamental parameters of intermediate redshift (z ≤ 1.2) disk galaxies. Advances in instrumentation of 8-10m class telescopes have made possible detailed measurements of galaxy luminosity, morphology, kinematics and mass, in both the optical and the infrared passbands. By studying such well known star formation indicators as [OII]3727A (in the optical) and Hα (redshifted to the infrared), the internal velocity structure and star formation rates of galaxies can be traced through this entire redshift regime. The combination of throughput and optimum seeing conditions yields spectra which can be combined with high resolution multiband imaging to explore the evolution of galaxies of various morphologies, and to place constraints on current models of galaxy formation and star formation histories.Out to redshifts of unity, these data form a high redshift Tully-Fisher relation that spans four magnitudes and extends to well below L*, with no obvious change in shape or slope with respect to the local relation. A comparison of disk surface brightness between local and high redshift samples yields an offset in accordance with distance-dependent surface brightness selection effects, as can the apparent change in disk size with redshift for disks of a given mass. These results support low Ω0 models of formation, and provide further evidence for modest increases in luminosity with lookback time for the bulk of the observed field spiral galaxy population.Finally, a comparison of spatially resolved spectra versus integrated emission line widths for distant galaxies suggests that observational constraints bias each type of observational sample toward different sub-groups of galaxies, with different evolutionary histories. Like varying selection effects, this will lead to a wide range of projected evolutionary trends.

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