The parallelism between galaxy clusters and early-type galaxies

Sciarratta

et al. 2020

A&A

Self Cite

Context. This is the second work dedicated to the observed parallelism between galaxy clusters (GCs) and early-type galaxies (ETGs). The focus is on the distribution of these systems in the scaling relations (SRs) observed when effective radii, effective surface brightness, total luminosities, and velocity dispersions are mutually correlated. Aims. Using the data of the Illustris simulation we speculate on the origin of the observed SRs. Methods. We compare the observational SRs extracted from the database of the WIde-field Nearby Galaxy-cluster Survey with the relevant parameters coming from the Illustris simulations. Then we use the simulated data at different redshift to infer the evolution of the SRs. Results. The comparison demonstrate that GCs at z ∼ 0 follow the same log(L)−log(σ) relation of ETGs and that both in the log(⟨I⟩e)−log(Re) and log(Re)−log(M*) planes the distribution of GCs is along the sequence defined by the brightest and massive early-type galaxies (BCGs). The Illustris simulation reproduces the tails of the massive galaxies visible both in the log(⟨I⟩e)−log(Re) and log(Re)−log(M*) planes, but fails to give the correct estimate of the effective radii of the dwarf galaxies that appear too large and those of GCs that are too small. The evolution of the SRs up to z = 4 permits to reveal the complex evolutionary paths of galaxies in the SRs and indicate that the line marking the zone of exclusion, visible in the log(⟨I⟩e)−log(Re) and the log(Re)−log(M*) planes, is the trend followed by virialized and passively evolving systems. Conclusions. We speculate that the observed SRs originate from the intersection of the virial theorem and a relation L = L0′σβ where the luminosities depend on the star formation history.

Section: The Log(r E )−Log(m * ) Planementioning

confidence: 99%

The parallelism between galaxy clusters and early-type galaxies

Sciarratta

et al. 2020

A&A

Self Cite

“…Since galaxies are always close to the dynamical equilibrium, the variation expected in luminosity and velocity dispersion, due to SF or merging events, are never bigger than the scatter of the relation ( ∼ 0.3 dex, which corresponds to a factor of 2). The DGs are the systems that are much distant to the virial equilibrium, probably for the strong feedback effects and SF activity still going on in many of them (Chiosi et al, 2019).…”

Section: The Faber-jackson Relationmentioning

confidence: 99%

“…These surveys have provided data for thousands of galaxies permitting a more robust statistical analysis of the physical drivers behind their formation and evolution. Several SRs, such as the velocity-luminosity or Tully-Fisher relation (hereafter TF (Tully and Fisher, 1977;Courteau et al, 2007)), the Faber-Jackson (FJ) relation (Faber and Jackson, 1976), the I e − R e (hereafter Kormendy relation KR (Kormendy, 1977)), the fundamental plane of galaxies (hereafter FP (Djorgovski and Davis, 1987;Dressler et al, 1987;Bender et al, 1992;Bernardi et al, 2003;Cappellari et al, 2006;La Barbera et al, 2008), the bulge mass-black hole (BH) mass relation (Magorrian et al, 1998), the mass-radius (MR) relation (Chiosi et al, 2019) are now robust for the galaxies of the nearby Universe and have now well constrained the physical laws governing the assembly of stellar systems.…”

Section: Introductionmentioning

confidence: 99%

“…The observed relations often depend on a number of factors, last but not least the structural parameter definitions (Courteau, 1996;Courteau, 1997), the environment that could influence the general distribution of galaxies (Mocz et al, 2012), the different fitting algorithms (Courteau et al, 2007;Avila-Reese et al, 2008;Hall et al, 2012) that provide different coefficients, redshift, and peculiar motions of the galaxies in the sample used (Willick et al, 1997;Fernández Lorenzo et al, 2011;Miller et al, 2011), projection effects and bandpass (Aaronson et al, 1986;D'Onofrio et al, 2008;Hall et al, 2012), the morphology of galaxies in the sample (Courteau et al, 2007;Tollerud et al, 2011), the stellar population content (Cappellari et al, 2006;Falcón-Barroso et al, 2011;Cappellari, 2013), the metallicity (Woo et al, 2008a), and the statistical properties of the dark matter (DM) halos [see e.g. Chiosi et al (2019)].…”

Section: Introductionmentioning

confidence: 99%

“…Lagos et al (2017), using cosmological simulations, confirmed the correlation between galaxy mass and specific angular momentum, and the evolution of the M s − j relation in passive and active galaxies, while Ferrarese et al (2006a) showed that the correlation of the mass of the BHs and the bulge mass is a key element in favor of the coevolution of the AGN with their host galaxies. Desmond and Wechsler (2017) used the FP to predict the amount of DM in the central regions of elliptical galaxies, while Ouellette et al (2017) found that the tilt of the FP correlates with the DM fraction of each galaxy and Chiosi et al (2019) demonstrated that the DM halo growth function is able to shape the mass-radius relation. We will see many other examples of the utility of SRs in this review.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

Marziani

Front. Astron. Space Sci.

2021

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.

The fundamental plane in the hierarchical context

2022

A&A

Self Cite

Context. The fundamental plane (FP) relation and the distribution of early-type galaxies (ETGs) in the FP projections cannot be easily explained in the hierarchical framework, where galaxies grow up by merging and as a result of star formation episodes. Aims. We want to show here that both the FP and its projections arise naturally from the combination of the virial theorem (VT) and a new time-dependent relation, describing how luminosity and stellar velocity dispersion change during galaxy evolution. This relation has the form of the Faber-Jackson relation, but a different physical meaning: the new relation is L = L0′(t)σβ(t), where its coefficients L0′ and β are time-dependent and can vary considerably from object to object, at variance with those obtained from the fit of the L − σ plane. Methods. By combining the VT and L = L0′(t)σβ(t) law, we derived an equation for each galaxy that is identical in form to the FP, but with coefficients depending on β. This allowed us to extract the solutions for β as a function of the structural parameters of ETGs and consequently calculate the coefficients of the FP-like equations. Results. We demonstrate that the observed properties of ETGs in the FP and its projections can be understood in terms of variations of β and L0′. These two parameters encrypt the history of galaxy evolution across the cosmic epochs and determine the future aspect of the FP and its projections. In particular, we show that the FP coefficients are simple averages of those in the FP-like equations valid for each galaxy, and that the variations of β naturally explain the distributions of ETGs observed in the FP projections and the direction of the border of the Zone of Exclusion.