scholarly journals [O ii] emitters in MultiDark-Galaxies and DEEP2

2020 ◽  
Vol 497 (4) ◽  
pp. 5432-5453
Author(s):  
G Favole ◽  
V Gonzalez-Perez ◽  
D Stoppacher ◽  
Á Orsi ◽  
J Comparat ◽  
...  
Keyword(s):  
Galaxy Formation ◽  
Broad Band ◽  
Analytical Models ◽  
Data Sets ◽  
Luminosity Functions ◽  
Galaxy Formation And Evolution ◽  
The Galaxy ◽  
Formation And Evolution ◽  
Emission Line Galaxies ◽  
Absolute Magnitudes

ABSTRACT We use three semi-analytical models (SAMs) of galaxy formation and evolution run on the same 1 h−1 Gpc MultiDark Planck2 cosmological simulation to investigate the properties of [O ii] emission line galaxies at redshift z ∼ 1. We compare model predictions with different observational data sets, including DEEP2–firefly galaxies with absolute magnitudes. We estimate the [O ii] luminosity ($L{\left[\rm{O\,{\small II}}\right]}$) of our model galaxies using the public code get_ emlines , which ideally assumes as input the instantaneous star formation rates (SFRs). This property is only available in one of the SAMs under consideration, while the others provide average SFRs, as most models do. We study the feasibility of inferring galaxies’    $L{\left[\rm{O\,{\small II}}\right]}$  from average SFRs in post-processing. We find that the result is accurate for model galaxies with dust attenuated   $L{\left[\rm{O\,{\small II}}\right]}$ ≲ 1042.2 erg s−1 ($\lt 5{{\ \rm per\ cent}}$ discrepancy). The galaxy properties that correlate the most with the model   $L{\left[\rm{O\,{\small II}}\right]}$ are the SFR and the observed-frame u and g broad-band magnitudes. Such correlations have r-values above 0.64 and a dispersion that varies with   $L{\left[\rm{O\,{\small II}}\right]}$ . We fit these correlations with simple linear relations and use them as proxies for   $L{\left[\rm{O\,{\small II}}\right]}$ , together with an observational conversion that depends on SFR and metallicity. These proxies result in [O ii] luminosity functions and halo occupation distributions with shapes that vary depending on both the model and the method used to derive   $L{\left[\rm{O\,{\small II}}\right]}$ . The amplitude of the clustering of model galaxies with   $L{\left[\rm{O\,{\small II}}\right]}$ >1040.4 erg s−1 remains overall unchanged on scales above 1 $\, h^{-1}$ Mpc, independently of the $L{\left[\rm{O\,{\small II}}\right]}$ computation.

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 The Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: exploring the halo occupation distribution model for emission line galaxies

2020 ◽  
Vol 499 (4) ◽  
pp. 5486-5507 ◽  
Author(s):  
S Avila ◽  
V Gonzalez-Perez ◽  
F G Mohammad ◽  
A de Mattia ◽  
C Zhao ◽  
...  
Keyword(s):  
Emission Line ◽  
Galaxy Formation ◽  
Distribution Model ◽  
Galaxy Formation And Evolution ◽  
Formation And Evolution ◽  
Physical Effects ◽  
Emission Line Galaxies ◽  
Halo Masses ◽  
The Impact ◽  
Halo Occupation Distribution

ABSTRACT We study the modelling of the halo occupation distribution (HOD) for the eBOSS DR16 emission line galaxies (ELGs). Motivated by previous theoretical and observational studies, we consider different physical effects that can change how ELGs populate haloes. We explore the shape of the average HOD, the fraction of satellite galaxies, their probability distribution function (PDF), and their density and velocity profiles. Our baseline HOD shape was fitted to a semi-analytical model of galaxy formation and evolution, with a decaying occupation of central ELGs at high halo masses. We consider Poisson and sub/super-Poissonian PDFs for satellite assignment. We model both Navarro–Frenk–White and particle profiles for satellite positions, also allowing for decreased concentrations. We model velocities with the virial theorem and particle velocity distributions. Additionally, we introduce a velocity bias and a net infall velocity. We study how these choices impact the clustering statistics while keeping the number density and bias fixed to that from eBOSS ELGs. The projected correlation function, wp, captures most of the effects from the PDF and satellites profile. The quadrupole, ξ2, captures most of the effects coming from the velocity profile. We find that the impact of the mean HOD shape is subdominant relative to the rest of choices. We fit the clustering of the eBOSS DR16 ELG data under different combinations of the above assumptions. The catalogues presented here have been analysed in companion papers, showing that eBOSS RSD+BAO measurements are insensitive to the details of galaxy physics considered here. These catalogues are made publicly available.

scholarly journals Deep learning for intensity mapping observations: component extraction

2020 ◽  
Vol 496 (1) ◽  
pp. L54-L58 ◽  
Author(s):  
Kana Moriwaki ◽  
Nina Filippova ◽  
Masato Shirasaki ◽  
Naoki Yoshida
Keyword(s):  
Deep Learning ◽  
Galaxy Formation ◽  
Large Scale ◽  
Generative Adversarial Networks ◽  
Intensity Mapping ◽  
Adversarial Networks ◽  
Galaxy Formation And Evolution ◽  
Formation And Evolution ◽  
Emission Line Galaxies ◽  
Two Populations

ABSTRACT Line intensity mapping (LIM) is an emerging observational method to study the large-scale structure of the Universe and its evolution. LIM does not resolve individual sources but probes the fluctuations of integrated line emissions. A serious limitation with LIM is that contributions of different emission lines from sources at different redshifts are all confused at an observed wavelength. We propose a deep learning application to solve this problem. We use conditional generative adversarial networks to extract designated information from LIM. We consider a simple case with two populations of emission-line galaxies; H $\rm \alpha$ emitting galaxies at $z$ = 1.3 are confused with [O iii] emitters at $z$ = 2.0 in a single observed waveband at 1.5 $\mu{\textrm m}$. Our networks trained with 30 000 mock observation maps are able to extract the total intensity and the spatial distribution of H $\rm \alpha$ emitting galaxies at $z$ = 1.3. The intensity peaks are successfully located with 74 per cent precision. The precision increases to 91 per cent when we combine five networks. The mean intensity and the power spectrum are reconstructed with an accuracy of ∼10 per cent. The extracted galaxy distributions at a wider range of redshift can be used for studies on cosmology and on galaxy formation and evolution.

THE LINK BETWEEN GALAXIES AND DARK MATTER

2011 ◽  
Vol 20 (10) ◽  
pp. 1771-1777
Author(s):  
HOUJUN MO
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Luminosity Function ◽  
The Other ◽  
Dark Matter Halos ◽  
Galaxy Formation And Evolution ◽  
The Galaxy ◽  
Galaxy Halo ◽  
Formation And Evolution ◽  
The Universe

Given that dark matter is gravitationally dominant in the universe, and that galaxy formation is closely related to dark matter halos, a key first step in understanding galaxy formation and evolution in the CDM paradigm is to quantify the galaxy-halo connection for galaxies of different properties. Here I will present results about the halo/galaxy connection obtained from two different methods. One is based on the conditional luminosity function, which describes the occupation of galaxies in halos of different masses, and the other is based on galaxy systems properly selected to represent dark halos.

scholarly journals Assembling Spiral Galaxies

1996 ◽  
Vol 171 ◽  
pp. 11-18
Author(s):  
R.C. Kennicutt
Keyword(s):  
Galaxy Formation ◽  
Spiral Galaxies ◽  
Dynamical Evolution ◽  
Star Formation History ◽  
Physical Mechanisms ◽  
Hubble Sequence ◽  
Galaxy Formation And Evolution ◽  
The Galaxy ◽  
History Of ◽  
Formation And Evolution

Nearby spiral galaxies offer vital clues to some of the most fundamental questions about galaxy formation and evolution: What is the star formation history of the universe, past and future? When did disks form, during the final stages of a single primeval collapse, or as a continuous or episodic process? What is the evolutionary nature of the Hubble sequence, and what are the physical mechanisms that dictate the present-day Hubble type of a galaxy? Was Hubble type imprinted at birth, or can it be deterined or at least modified by infall, mergers, or secular dynamical evolution within the galaxy? These issues are not specific to spirals, of course, and much of this conference will address just these questions in a broader context. However present-day spirals offer unique advantages for studying these problems; they exhibit a broad range of dynamical and evolutionary properties, and the dynamical fragility of disks makes them excellent seismometers of galaxy interaction and merger rates at recent epochs.

scholarly journals The VIRGO PN population and the mass assembly in M87

2016 ◽  
Vol 12 (S323) ◽  
pp. 288-292
Author(s):  
Alessia Longobardi ◽  
Magda Arnaboldi ◽  
Ortwin Gerhard
Keyword(s):  
Galaxy Formation ◽  
Virgo Cluster ◽  
Galaxy Halos ◽  
Galaxy Formation And Evolution ◽  
Low Surface Brightness ◽  
The Galaxy ◽  
Galaxy Halo ◽  
Formation And Evolution ◽  
Mass Assembly ◽  
Intracluster Light

AbstractCosmological simulations allow us to study in detail the evolution of galaxy halos in cluster environments, but the extremely low surface brightness of such components makes it difficult to gather observational constraints. Planetary nebulas (PNs) offer a unique tool to investigate these environments owing to their strong [OIII] emission line. We study the light and kinematics of the Virgo cluster and its central galaxy, M87, prime targets to address the topic of galaxy formation and evolution in dense environments. We make use of a deep and extended PN sample (~300 objects) that extends out to 150 kpc in radius from M87’s centre. We show that at all distance the galaxy halo overlaps with the Virgo intracluster light (ICL). Halo and ICL are dynamically distinct components with different parent stellar populations, consistent with the halo of M87 being redder and more metal rich than the ICL. The synergy between PN kinematic information and deep V/B-band photometry made it possible to unravel an ongoing accretion process in the outskirt of M87. This accretion event represents a non-negligible perturbation of the halo light, showing that this galaxy is still growing by accretion of smaller systems.

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 Observations of dwarfs in nearby voids: implications for galaxy formation and evolution

2014 ◽  
Vol 11 (S308) ◽  
pp. 606-609
Author(s):  
Simon A. Pustilnik
Keyword(s):  
Galaxy Formation ◽  
Dwarf Galaxy ◽  
Oxygen Deficiency ◽  
Evolutionary Status ◽  
Galaxy Formation And Evolution ◽  
Upper Limits ◽  
Void Galaxies ◽  
The Galaxy ◽  
Formation And Evolution ◽  
Hydrogen Mass

AbstractThe intermediate results of the ongoing study of deep samples of ∼200 galaxies residing in nearby voids, are presented. Their properties are probed via optical spectroscopy, ugri surface photometry, and HI 21-cm line measurements, with emphasis on their evolutionary status. We derive directly the hydrogen mass M(HI), the ratio M(HI)/LB and the evolutionary parameter gas-phase O/H. Their luminosities and integrated colours are used to derive stellar mass M* and the second evolutionary parameter – gas mass-fraction fg). The colours of the outer parts, typically representative of the galaxy oldest stellar population, are used to estimate the upper limits on time since the beginning of the main SF episode. We compare properties of void galaxies with those of the similar late-type galaxies in denser environments. Most of void galaxies show smaller O/H for their luminosity, in average by ∼30\%, indicating slower evolution. Besides, the fraction of ∼10\% of the whole void sample or ∼30\% of the least luminous void LSB dwarfs show the oxygen deficiency by a factor of 2–5. The majority of this group appear very gas-rich, with fg ∼(95–99)%, while their outer parts appear rather blue, indicating the time of onset of the main star-formation episode of less than 1–4 Gyr. Such unevolved LSBD galaxies appear not rare among the smallest void objects, but turned out practically missed to date due to the strong observational selection effects. Our results evidense for unusual evolutionary properties of the sizable fraction of void galaxies, and thus, pose the task of better modelling of dwarf galaxy formation and evolution in voids.

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 The Stellar Population of the Thin Disk

2009 ◽  
Vol 5 (S265) ◽  
pp. 304-312
Author(s):  
Carlos Allende Prieto
Keyword(s):  
Galaxy Formation ◽  
Stellar Population ◽  
Milky Way ◽  
Galactic Disk ◽  
Symmetry Plane ◽  
Thin Disk ◽  
Solar Neighborhood ◽  
Galaxy Formation And Evolution ◽  
The Galaxy ◽  
Formation And Evolution

AbstractWe discuss recent observations of stars located close to the symmetry plane of the Milky Way, and examine them in the context of theories of Galaxy formation and evolution. The kinematics, ages, and compositions of thin disk stars in the solar neighborhood display complex patterns, and interesting correlations. The Galactic disk does not seem to pose any unsurmountable obstacles to hierarchical galaxy formation theories, but a model of the Milky Way able to reproduce the complexity found in the data will likely require a meticulous study of a significant fraction of the stars in the Galaxy. Making such an observational effort seems necessary in order to make a physics laboratory out of our own galaxy, and ultimately ensure that the most relevant processes are properly understood.

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