scholarly journals Radio-loud AGN in the first LoTSS data release

2019 ◽  
Vol 622 ◽  
pp. A12 ◽  
Author(s):  
M. J. Hardcastle ◽  
W. L. Williams ◽  
P. N. Best ◽  
J. H. Croston ◽  
K. J. Duncan ◽  
...  
Keyword(s):  
Galaxy Formation ◽  
Galactic Nuclei ◽  
Lifetime Distribution ◽  
Analytical Models ◽  
Jet Physics ◽  
Star Forming ◽  
Galaxy Formation And Evolution ◽  
Sky Survey ◽  
Formation And Evolution ◽  
Good Agreement

We constructed a sample of 23 344 radio-loud active galactic nuclei (RLAGN) from the catalogue derived from the LOFAR Two-Metre Sky Survey (LoTSS) survey of the HETDEX Spring field. Although separating AGN from star-forming galaxies remains challenging, the combination of spectroscopic and photometric techniques we used gives us one of the largest available samples of candidate RLAGN. We used the sample, combined with recently developed analytical models, to investigate the lifetime distribution of RLAGN. We show that large or giant powerful RLAGN are probably the old tail of the general RLAGN population, but that the low-luminosity RLAGN candidates in our sample, many of which have sizes < 100 kpc, either require a very different lifetime distribution or have different jet physics from the more powerful objects. We then used analytical models to develop a method of estimating jet kinetic powers for our candidate objects and constructed a jet kinetic luminosity function based on these estimates. These values can be compared to observational quantities, such as the integrated radiative luminosity of groups and clusters, and to the predictions from models of RLAGN feedback in galaxy formation and evolution. In particular, we show that RLAGN in the local Universe are able to supply all the energy required per comoving unit volume to counterbalance X-ray radiative losses from groups and clusters and thus prevent the hot gas from cooling. Our computation of the kinetic luminosity density of local RLAGN is in good agreement with other recent observational estimates and with models of galaxy formation.

scholarly journals Dust reddening in star-forming galaxies

2012 ◽  
Vol 8 (S292) ◽  
pp. 291-291
Author(s):  
Ting Xiao ◽  
Tinggui Wang ◽  
Huiyuan Wang ◽  
Hongyan Zhou ◽  
Honglin Lu ◽  
...  
Keyword(s):  
Star Formation ◽  
Gas Phase ◽  
Galaxy Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Analytical Models ◽  
Star Forming ◽  
Crucial Component ◽  
Galaxy Formation And Evolution ◽  
Formation And Evolution

AbstractDust is a crucial component of galaxies in modifying the observed properties of galaxies. Previous studies have suggested that dust reddening in star-forming galaxies is correlated with star formation rate (SFR), luminosity, gas-phase metallicity (Z), stellar mass (M*) and inclination. In this work we investigate the fundamental relations between dust reddening and physical properties of galaxies, and obtain a well-defined empirical recipe for dust reddening. The empirical formulae can be incorporated into semi-analytical models of galaxy formation and evolution to estimate the dust reddening and facilitate comparison with observations.

scholarly journals A New Catalog of Isolated Galaxies

2009 ◽  
Vol 5 (S267) ◽  
pp. 464-464
Author(s):  
J. A. Vázquez-Mata ◽  
H. M. Hernández-Toledo ◽  
Changbom Park ◽  
Yun-Young Choi
Keyword(s):  
Galaxy Formation ◽  
Environmental Effects ◽  
Comparative Studies ◽  
Sloan Digital Sky Survey ◽  
Selection Algorithm ◽  
Isolated Galaxies ◽  
Galaxy Formation And Evolution ◽  
Sky Survey ◽  
Data Release ◽  
Formation And Evolution

We present a new catalog of isolated galaxies (coined as UNAM–KIAS) obtained through an automated systematic search. The 1520 isolated galaxies were found in ~ 1.4 steradians of the sky in the Sloan Digital Sky Survey Data Release 5 (SDSS DR5) photometry. The selection algorithm was implemented from a variation of the criteria developed by Karachentseva (1973), with full redshift information. This new catalog is aimed to carry out comparative studies of environmental effects and constraining the currently competing scenarios of galaxy formation and evolution.

scholarly journals Past, Present, and Future of the Scaling Relations of Galaxies and Active Galactic Nuclei

2021 ◽  
Vol 8 ◽  
Author(s):  
Mauro D’Onofrio ◽  
Paola Marziani ◽  
Cesare Chiosi
Keyword(s):  
Active Galactic Nuclei ◽  
Galaxy Formation ◽  
Galactic Nuclei ◽  
Scaling Relations ◽  
Short History ◽  
Physical Mechanisms ◽  
Galaxy Formation And Evolution ◽  
The Galaxy ◽  
History Of ◽  
Formation And Evolution

We review the properties of the established Scaling Relations (SRs) of galaxies and active galactic nuclei (AGN), focusing on their origin and expected evolution back in time, providing a short history of the most important progresses obtained up to now and discussing the possible future studies. We also try to connect the observed SRs with the physical mechanisms behind them, examining to what extent current models reproduce the observational data. The emerging picture clarifies the complexity intrinsic to the galaxy formation and evolution process as well as the basic uncertainties still affecting our knowledge of the AGN phenomenon. At the same time, however, it suggests that the detailed analysis of the SRs can profitably contribute to our understanding of galaxies and AGN.

scholarly journals Direct Evidence for AGN-Driven Winds in a z = 1.5 Radio Galaxy

2009 ◽  
Vol 5 (S267) ◽  
pp. 407-407
Author(s):  
Eric Steinbring
Keyword(s):  
Adaptive Optics ◽  
Galaxy Formation ◽  
Direct Evidence ◽  
Radio Galaxy ◽  
Massive Galaxies ◽  
Radio Jets ◽  
Galaxy Formation And Evolution ◽  
Formation And Evolution ◽  
Integral Field Spectrograph ◽  
Good Agreement

Feedback from AGN is a key component in most current models of galaxy formation and evolution. For the most massive galaxies, heating and removal of gas by the AGN could precipitate an abrupt quenching of star formation during a dramatic blow-out phase. The “smoking gun” for such a scenario would be direct evidence of powerful outflows associated with the jet. I present some preliminary results of a program to look for these in high-z radio galaxies (HzRGs). Recent observations of the z = 1.5 radio galaxy 3C 230 obtained with the NIFS integral-field spectrograph and Altair laser adaptive optics facility on Gemini North are shown. These reveal with unprecedented resolution the complex kinematics of this system in redshifted Hα and [N ii] emission. The bi-polar velocity field is aligned with the jet axis, with a kinematic center associated with the radio core itself, and turbulent edges approaching the galaxy's escape velocity. This suggests a gas mass of roughly 1011M⊙ has been propagating outwards for 107 to 108 years, corresponding to a mass loss of roughly 102–3M⊙ yr−1, based on its velocity and spatial extent. This is in good agreement with the energetics and typical ages of radio jets, and likely heralds the onset of the “red and dead” stage for this HzRG.

scholarly journals The influence of massive stars on the interstellar medium

1999 ◽  
Vol 193 ◽  
pp. 627-635
Author(s):  
M. Sally Oey
Keyword(s):  
Galaxy Formation ◽  
Massive Stars ◽  
Stellar Winds ◽  
H Ii Regions ◽  
Feedback Effects ◽  
Star Forming ◽  
Galaxy Formation And Evolution ◽  
Formation And Evolution ◽  
The Relationship ◽  
Warm Ionized Medium

On scales ranging from pcs to kpcs, the relationship between stellar and gaseous galactic components forms the basis for interpreting observations of galaxies and understanding galaxy formation and evolution. Feedback effects from massive stars dominate the structure, ionization, kinematics, and enrichment of the gaseous ISM in star-forming galaxies. On galactic scales, the ionizing radiation from these stars creates populations of H II regions and the diffuse, warm ionized medium. Likewise, superbubbles created by stellar winds and supernovae strongly influence the structure, kinematics, and balance of the multiphase ISM. This contribution reviews these feedback effects of massive stars on the global ISM.

scholarly journals A Review of the Theory of Galactic Winds Driven by Stellar Feedback

Galaxies ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 114 ◽  
Author(s):  
Dong Zhang
Keyword(s):  
Galaxy Formation ◽  
Mass Function ◽  
Future Research ◽  
Star Forming ◽  
Stellar Feedback ◽  
Galactic Winds ◽  
Galaxy Formation And Evolution ◽  
Supernova Explosions ◽  
Formation And Evolution ◽  
Magnetohydrodynamic Simulations

Galactic winds from star-forming galaxies are crucial to the process of galaxy formation and evolution, regulating star formation, shaping the stellar mass function and the mass-metallicity relation, and enriching the intergalactic medium with metals. Galactic winds associated with stellar feedback may be driven by overlapping supernova explosions, radiation pressure of starlight on dust grains, and cosmic rays. Galactic winds are multiphase, the growing observations of emission and absorption of cold molecular, cool atomic, ionized warm and hot outflowing gas in a large number of galaxies have not been completely understood. In this review article, I summarize the possible mechanisms associated with stars to launch galactic winds, and review the multidimensional hydrodynamic, radiation hydrodynamic and magnetohydrodynamic simulations of winds based on various algorithms. I also briefly discuss the theoretical challenges and possible future research directions.

scholarly journals Feedback from AGN: The Kinetic/Radio Luminosity Function

2009 ◽  
Vol 5 (S267) ◽  
pp. 402-402
Author(s):  
Gabriele Melini ◽  
Fabio La Franca ◽  
Fabrizio Fiore
Keyword(s):  
Galaxy Formation ◽  
Probability Distribution Function ◽  
Luminosity Function ◽  
Complete Sample ◽  
X Ray ◽  
Galaxy Formation And Evolution ◽  
Formation And Evolution ◽  
Radio Luminosity Function ◽  
Radio Power ◽  
Good Agreement

We have measured the probability distribution function of the ratio RX = log L1.4/LX, where L1.4/LX = ν Lν(1.4 GHz)/LX(2–10 keV), between the 1.4 GHz and the unabsorbed 2–10 keV luminosities and its dependence on LX and z. We have used a complete sample of ~1800 hard X-ray selected AGN, observed in the 1.4 GHz band, cross-correlated in order to exclude FR II-type objects, and thus obtain a contemporaneous measure of the radio and X-ray emission. The distribution P(RX|LX,z) is shown in Figure 1. Convolution of the distribution P(RX|LX,z) with the 2–10 keV X-ray AGN luminosity function from La Franca et al. (2005) and the relations between radio power and kinetic energy from Best et al. (2006) and Willott et al. (1999) allows us to derive the AGN kinetic power and its evolution. As shown in Figure 1, our results are in good agreement with the predictions of the most recent models of galaxy formation and evolution (e.g., Croton et al. 2006), where AGN radio feedback is required to quench the star formation.

scholarly journals Euclid: the selection of quiescent and star-forming galaxies using observed colours

2020 ◽  
Vol 494 (2) ◽  
pp. 2337-2354
Author(s):  
L Bisigello ◽  
U Kuchner ◽  
C J Conselice ◽  
S Andreon ◽  
M Bolzonella ◽  
...  
Keyword(s):  
Galaxy Formation ◽  
Rest Frame ◽  
Star Forming ◽  
Galaxy Formation And Evolution ◽  
Formation And Evolution ◽  
Selection Of ◽  
Key Questions

ABSTRACT The Euclid mission will observe well over a billion galaxies out to z ∼ 6 and beyond. This will offer an unrivalled opportunity to investigate several key questions for understanding galaxy formation and evolution. The first step for many of these studies will be the selection of a sample of quiescent and star-forming galaxies, as is often done in the literature by using well-known colour techniques such as the ‘UVJ’ diagram. However, given the limited number of filters available for the Euclid telescope, the recovery of such rest-frame colours will be challenging. We therefore investigate the use of observed Euclid colours, on their own and together with ground-based u-band observations, for selecting quiescent and star-forming galaxies. The most efficient colour combination, among the ones tested in this work, consists of the (u − VIS) and (VIS − J) colours. We find that this combination allows users to select a sample of quiescent galaxies complete to above $\sim 70{{\ \rm per\ cent}}$ and with less than 15${{\ \rm per\ cent}}$ contamination at redshifts in the range 0.75 &lt; z &lt; 1. For galaxies at high-z or without the u-band complementary observations, the (VIS − Y) and (J − H) colours represent a valid alternative, with $\gt 65{{\ \rm per\ cent}}$ completeness level and contamination below 20${{\ \rm per\ cent}}$ at 1 &lt; z &lt; 2 for finding quiescent galaxies. In comparison, the sample of quiescent galaxies selected with the traditional UVJ technique is only $\sim 20{{\ \rm per\ cent}}$ complete at z &lt; 3, when recovering the rest-frame colours using mock Euclid observations. This shows that our new methodology is the most suitable one when only Euclid bands, along with u-band imaging, are available.

scholarly journals Massive and old quiescent galaxies at high redshift

2019 ◽  
Vol 632 ◽  
pp. A80 ◽  
Author(s):  
Giacomo Girelli ◽  
Micol Bolzonella ◽  
Andrea Cimatti
Keyword(s):  
Star Formation ◽  
Galaxy Formation ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Stellar Mass ◽  
Analytical Models ◽  
Galaxy Formation And Evolution ◽  
Formation And Evolution ◽  
Mass Assembly ◽  
Mass Functions

Aims. Questions of how massive quiescent galaxies rapidly assembled and how abundant they are at high redshift are increasingly important in the study of galaxy formation. Looking at these systems can shed light on the processes of galaxy mass assembly and quenching of the star formation at early epochs. In order to address these questions, we aim to identify and characterize massive quiescent galaxies from z ∼ 2.5 out to the highest redshifts at which these systems can be found. The final purpose is to compare the results with the predictions of state-of-the-art semi-analytical models of galaxy formation and evolution. Methods. We defined observer-frame color–color diagrams to optimally select quiescent galaxies at z >  2.5 and applied them to the COSMOS2015 catalog. We refined the spectral energy distribution (SED) fitting analysis for the selected candidates to confirm their quiescent nature, then derived their number density, mass density, and stellar mass functions. Finally, we compared the results with previous observations and some current semi-analytic models. Results. We selected candidates for quiescent galaxies in the redshift range 2.5 ≲ z ≲ 4.5 from the COSMOS2015 catalog by means of two color–color diagrams. The additional SED fitting analysis allowed us to select 128 galaxies, consistent with being massive (log(M*/M⊙)≥10.6), old (ages ≳0.5 Gyr), and quiescent (log(sSFR [yr−1]) ≤ −10.5) objects at high redshift (2.5 <  z <  4.5). Their number and mass densities are in fair agreement with previous observations and, if confirmed, show a discrepancy with current semi-analytical models of galaxy formation and evolution, that underpredict the number of massive quiescent systems up to a factor of ∼12 at 2.5 ≤ z <  3.0 and ∼10 at z ∼ 4.0. The evolution of the stellar mass functions (SMFs) of these systems is similar to previous estimates and indicates a disagreement with models, particularly with regard to the shape of the SMF. Conclusions. The present results add further evidence to the possibility that massive and quiescent galaxies can exist out to at least z ∼ 4. If future spectroscopic observations carried out with, for example, the James Webb Space Telecope (JWST), confirm the substantial presence of such a population, further work on modeling the stellar mass assembly, as well as supermassive black hole accretion and feedback processes at early cosmic epochs, is needed to understand how these systems formed, evolved, and quenched their star formation.

Planetary nebulae in the (extra)-galactic context: Probing chemical evolution in star-forming galaxies

2018 ◽  
Vol 14 (S343) ◽  
pp. 174-180
Author(s):  
Letizia Stanghellini
Keyword(s):  
Galaxy Formation ◽  
Planetary Nebulae ◽  
H Ii Regions ◽  
Chemical Abundances ◽  
Star Forming ◽  
Galaxy Formation And Evolution ◽  
Formation History ◽  
Chemical Content ◽  
Formation And Evolution ◽  
Powerful Constraint

AbstractThe populations of planetary nebulae (PNe) probe metallicity and chemical content (and its evolution) of the parent galaxy, giving clues to galaxy formation and evolution. This sub-field of extra-galactic PN research has been particularly active in the recent years. Comparison of data and models yielded estimates of global cosmic enrichment and provided constraints to galaxy formation history. In external spiral galaxies, the chemical contents of PNe and H II regions can be compared to disclose possible evolution of the radial metallicity gradient, which is, in turn, a powerful constraint to galactic chemical evolutionary models. In the Milky Way, recent PN progenitor dating and new chemical abundances offer an updated look into our own Galaxy. Collectively, Galactic and extra-galactic radial metallicity gradients from emission-line probes (PNe and H II regions) can be compared to have a cosmological outlook on galactic evolution.

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