The nucleation fraction of local volume galaxies

Hoyer, Nils; Neumayer, Nadine; Georgiev, Iskren Y.; Seth, Anil; Greene, Jenny E.

doi:10.1093/mnras/stab2277

Cited by 29 publications

(23 citation statements)

References 161 publications

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“…Recently, Poulain et al (2021) studied the nucleation of nearby dwarfs (10 Mpc< d <45 Mpc, and 10 5.5 M ⊙ < M * ,galaxy < 10 9 M ⊙ ; see Habas et al 2020) in low-to-moderate-density environments and found a global nucleation fraction of ∼ 0.23 (including both early-and late-types). The Local Volume (d ≲ 12 Mpc) sample of galaxies (10 2.5 M ⊙ < M * ,galaxy < 10 11.5 M ⊙ ) studied in Hoyer et al (2021) has a global nucleation fraction of ∼ 0.24. Similarly, the analysis of Carlsten et al (2022) of Local Volume dwarfs (10 5.5 M ⊙ < M * ,galaxy < 10 8.5 M ⊙ ) determined a global nucleation fraction of 0.23.…”

Section: Nucleation Fractionmentioning

confidence: 99%

Photometric properties of nuclear star clusters and their host galaxies in the Fornax cluster

Salo

Venhola

et al. 2022

A&A

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Aims. We aim to investigate the relations between nuclear star clusters (NSCs) and their host galaxies and to offer a comparison between the structural properties of nucleated and non-nucleated galaxies. We also address the environmental influences on the nucleation of galaxies in the Fornax main cluster and the Fornax A group. Methods. We selected 557 galaxies (10 5.5 M ⊙ < M * ,galaxy < 10 11.5 M ⊙ ) for which structural decomposition models and non-parametric morphological measurements are available from our previous work. We determined the nucleation of galaxies based on a combination of visual inspection of galaxy images and residuals from multi-component decomposition models, as well as using a model selection statistic, the Bayesian information criterion (BIC), to avoid missing any faint nuclei. We also tested the BIC as an unsupervised method to determine the nucleation of galaxies. We characterised the NSCs using the nucleus components from the multi-component models conducted in the g ′ , r ′ , and i ′ bands.Results. Overall, we find a dichotomy in the properties of nuclei that reside in galaxies more or less massive than M * ,galaxy ≈ 10 8.5 M ⊙ . In particular, we find that the nuclei tend to be bluer than their host galaxies and follow a scaling relation of M * ,nuc ∝ M * ,galaxy 0.5 for M * ,galaxy < 10 8.5 M ⊙ . In galaxies with M * ,galaxy > 10 8.5 M ⊙, we find redder nuclei compared to the host galaxy, which follows M * ,nuc ∝ M * ,galaxy . Comparing the properties of nucleated and non-nucleated early-type galaxies, we find that nucleated galaxies tend to be redder in global (g ′ − r ′ ) colour, have redder outskirts relatively to their own inner regions (∆(g ′ − r ′ )), are less asymmetric (A), and exhibit less scatter in the brightest second-order moment of light (M 20 ) than their non-nucleated counterparts at a given stellar mass. However, with the exception of ∆(g ′ − r ′ ) and the Gini coefficient (G), we do not find any significant correlations with cluster-centric distance. Yet, we find the nucleation fractions to be typically higher in the Fornax main cluster than in the Fornax A group, and that the nucleation fraction is highest towards the centre of their respective environments. Additionally, we find that the observed ultra-compact dwarf (UCD) fraction (i.e. the number of UCDs over the number of UCDs and nucleated galaxies) in Fornax and Virgo peaks at the cluster centre and is consistent with the predictions from simulations. Lastly, we find that the BIC can recover our labels of nucleation up to an accuracy of 97% without interventions. Conclusions. The different trends in NSC properties suggest that different processes are at play at different host stellar masses. A plausible explanation is that the combination of globular cluster in-spiral and in situ star formation play a key role in the build-up of NSCs. In addition, the environment is clearly another important factor in the nucleation of galaxies, particularly at the centre of the cluster where the nucleation and UCD fractions ...

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Section: Nucleation Fractionmentioning

confidence: 99%

Photometric properties of nuclear star clusters and their host galaxies in the Fornax cluster

Salo

Venhola

et al. 2022

A&A

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“…This result has been interpreted as suggestive that the formation of NSCs in these dwarf galaxies are dominated by the in-spiral and merger of GCs (although NSCs could also grow through in-situ star formation after forming). For galaxies with stellar mass ∼ 10 7 𝑀 , the nucleation fraction is 0.3 − 0.4 in Virgo and Coma cluster, and ∼ 0.2 in the Local Volume (Sánchez-Janssen et al 2019;Hoyer et al 2021;Carlsten et al 2021).…”

Section: Future Distribution Of Gcsmentioning

confidence: 98%

“…The possible connection between GCs and NSCs has been a topic of active research (Sánchez-Janssen et al 2019;Hoyer et al 2021;Carlsten et al 2021). It was found that the nucleation fraction (i.e.…”

Section: Future Distribution Of Gcsmentioning

confidence: 99%

The spatial distribution of globular clusters in dwarf spheroidal galaxies and the timing problem

Sanchez-Salcedo,

Lora

2022

Preprint

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The dynamical friction timescale of massive globular clusters (GCs) in the inner regions of cuspy dark haloes in dwarf spheroidal (dSph) galaxies can be much shorter than the Hubble time. This implies that a small fraction of the GCs is expected to be caught close to the centre of these galaxies. We compare the radial distribution of GCs predicted in simple Monte Carlo models with that of a sample of 38 spectroscopically confirmed GCs plus 17 GC candidates, associated mainly to low-luminosity dSph galaxies. If dark matter haloes follow an NFW profile, the observed number of off-center GCs at projected distances less than one half the galaxy effective radius is significantly higher than models predict. This timing problem can be viewed as a fine-tuning of the starting GC distances. As a result of the short sinking timescale for GCs in the central regions, the radial distribution of GCs is expected to evolve significantly during the next 1 − 2 Gyr. However, dark matter haloes with cores of size comparable to the galaxy effective radii can lead to a slow orbital in-spiral of GCs in the central regions of these galaxies, providing a simple solution to the timing problem. We also examine any indication of mass segregation in the summed distribution of our sample of GCs.

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“…The binned galaxy nucleation fraction, NSC masses and stellar masses for galaxies in the Coma, Virgo, Fornax clusters, as well as the MW, M31 and M81, are taken from the compilation of RSJ19 and references therein. During the proofs stage of this manuscript, several other compilations of Local Volume nucleation fraction data were published in the studies of Carlsten et al (2021);Hoyer et al (2021); Zanatta et al (2021); Poulain et al (2021), to which we refer interested readers.…”

Section: Datamentioning

confidence: 99%

On the link between nuclear star cluster and globular cluster system mass, nucleation fraction and environment

Leaman,

van de Ven

2021

Preprint

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We present a simple model for the host mass dependence of the galaxy nucleation fraction ( 𝑓 𝑛𝑢𝑐 ), the galaxy's nuclear star cluster (NSC) mass and the mass in its surviving globular clusters (𝑀 𝐺𝐶,𝑜𝑏𝑠 ). Considering the mass and orbital evolution of a GC in a galaxy potential, we define a critical mass limit (𝑀 𝐺𝐶,𝑙𝑖𝑚 ) above which a GC can simultaneously in-spiral to the galaxy centre due to dynamical friction and survive tidal dissolution, to build up the NSC. The analytic expression for this threshold mass allows us to model the nucleation fraction for populations of galaxies. We find that the slope and curvature of the initial galaxy size-mass relation is the most important factor (with the shape of the GC mass function a secondary effect) setting the fraction of galaxies that are nucleated at a given mass. The well defined skewnormal 𝑓 𝑛𝑢𝑐 −𝑀 𝑔𝑎𝑙 observations in galaxy cluster populations are naturally reproduced in these models, provided there is an inflection in the initial size-mass relation at 𝑀 𝑔𝑎𝑙 ∼ 10 9.5 M . Our analytic model also predicts limits to the 𝑀 𝑔𝑎𝑙 − 𝑀 𝐺𝐶,𝑡𝑜𝑡 and 𝑀 𝑔𝑎𝑙 − 𝑀 𝑁 𝑆𝐶 relations which bound the scatter of the observational data. Moreoever, we illustrate how these scaling relations and 𝑓 𝑛𝑢𝑐 vary if the star cluster formation efficiency, GC mass function, galaxy environment or galaxy size-mass relation are altered. Two key predictions of our model are: 1) galaxies with NSC masses greater than their GC system masses are more compact at fixed stellar mass, and 2) the fraction of nucleated galaxies at fixed galaxy mass is higher in denser environments. That a single model framework can reproduce both the NSC and GC scaling relations provides strong evidence that GC in-spiral is an important mechanism for NSC formation.

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The nucleation fraction of local volume galaxies

Cited by 29 publications

References 161 publications

Photometric properties of nuclear star clusters and their host galaxies in the Fornax cluster

Photometric properties of nuclear star clusters and their host galaxies in the Fornax cluster

The spatial distribution of globular clusters in dwarf spheroidal galaxies and the timing problem

On the link between nuclear star cluster and globular cluster system mass, nucleation fraction and environment

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