Morphological evolution and galactic sizes in the L-Galaxies SA model

Irodotou, Dimitrios; Thomas, P.; Henriques, Bruno M. B.; Sargent, M.; Hislop, J. M.

doi:10.1093/mnras/stz2365

Cited by 28 publications

(23 citation statements)

References 242 publications

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“…),Weinzirl et al (2009),Gargiulo et al (2015),Pedrosa & Tissera (2015),Irodotou et al (2019),Obreschkow et al (2020), andZanisi et al (2020). Finally, we note that even though…”

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confidence: 52%

Using angular momentum maps to detect kinematically distinct galactic components

Irodotou

Thomas

2020

Monthly Notices of the Royal Astronomical Society

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In this work, we introduce a physically motivated method of performing disc/spheroid decomposition of simulated galaxies, which we apply to the eagle sample. We make use of the healpix package to create Mollweide projections of the angular momentum map of each galaxy’s stellar particles. A number of features arise on the angular momentum space which allows us to decompose galaxies and classify them into different morphological types. We assign stellar particles with angular separation of less/greater than 30° from the densest grid cell on the angular momentum sphere to the disc/spheroid components, respectively. We analyse the spatial distribution for a subsample of galaxies and show that the surface density profiles of the disc and spheroid closely follow an exponential and a Sérsic profile, respectively. In addition discs rotate faster, have smaller velocity dispersions, are younger and are more metal rich than spheroids. Thus, our morphological classification reproduces the observed properties of such systems. Finally, we demonstrate that our method is able to identify a significant population of galaxies with counter-rotating discs and provide a more realistic classification of such systems compared to previous methods.

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“…),Weinzirl et al (2009),Gargiulo et al (2015),Pedrosa & Tissera (2015),Irodotou et al (2019),Obreschkow et al (2020), andZanisi et al (2020). Finally, we note that even though…”

mentioning

confidence: 52%

Using angular momentum maps to detect kinematically distinct galactic components

Irodotou

Thomas

2020

Monthly Notices of the Royal Astronomical Society

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“…This j * − M * law has been widely used in recent years to constrain and test both (semi-)analytic models and hydrodynamical simulations (e.g. Genel et al 2015;Pedrosa & Tissera 2015;Obreja et al 2016;Lagos et al 2017;Tremmel et al 2017;El-Badry et al 2018;Stevens et al 2018;Zoldan et al 2018;Irodotou et al 2019).…”

Section: Introductionmentioning

confidence: 99%

A tight angular-momentum plane for disc galaxies

Piña

Posti

Pezzulli

et al. 2021

A&A

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The relations between the specific angular momenta (j) and masses (M) of galaxies are often used as a benchmark in analytic models and hydrodynamical simulations as they are considered to be amongst the most fundamental scaling relations. Using accurate measurements of the stellar (j*), gas (jgas), and baryonic (jbar) specific angular momenta for a large sample of disc galaxies, we report the discovery of tight correlations between j, M, and the cold gas fraction of the interstellar medium (fgas). At fixed fgas, galaxies follow parallel power laws in 2D (j, M) spaces, with gas-rich galaxies having a larger j* and jbar (but a lower jgas) than gas-poor ones. The slopes of the relations have a value around 0.7. These new relations are amongst the tightest known scaling laws for galaxies. In particular, the baryonic relation (jbar − Mbar − fgas), arguably the most fundamental of the three, is followed not only by typical discs but also by galaxies with extreme properties, such as size and gas content, and by galaxies previously claimed to be outliers of the standard 2D j − M relations. The stellar relation (j* − M* − fgas) may be connected to the known j* − M*-bulge fraction relation; however, we argue that the jbar − Mbar − fgas relation can originate from the radial variation in the star formation efficiency in galaxies, although it is not explained by current disc instability models.

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“…Table 1 quotes the different SAMs with their cosmological parameters and parent simulations. Following Guo et al (2011), Knebe et al (2015), and Irodotou et al (2019), we only considered galaxies with stellar masses larger than ∼ 10 9 M (7 × 10 8 ℎ −1 M ) for the MS I SAMs (see queries to retrieve these data in the appendix of Paper I).…”

Section: Semi-analytical Models Of Galaxy Formationmentioning

confidence: 99%

Compact groups from semi-analytical models of galaxy formation -- III: purity and completeness of Hickson-like catalogues

Taverna,

Diaz-Gimenez,

Zandivarez

et al. 2022

Preprint

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Many catalogues of isolated compact groups of galaxies (CGs) have been extracted using Hickson's criteria to identify isolated, dense systems of galaxies, with at least three or four galaxies concordant in magnitude and redshift. But is not clear to what extent the catalogues of CGs are complete and reliable, relative to 3D truly isolated, dense groups. Using five different semi-analytical models of galaxy formation (SAMs), we identify isolated dense groups in 3D real space, containing at least three galaxies. We then build mock redshift space galaxy catalogues and run a Hickson-like CG finder. We find that the Hickson-like algorithm in redshift space is poor at recovering 3D CGs of at least 3 galaxies, with a purity of ∼ 10% and a completeness of ∼ 22%. Among the ∼ 90% of spurious systems, typically 60% are dense structures that failed the 3D isolation criteria, while the remaining 40% are chance alignments of galaxies along the line of sight, nearly all of which are within regular groups, with some variation with the SAM used for the analysis. In other words, while only 10% of CGs are isolated dense groups, as intended, half are dense structures embedded within larger groups, and one-third are chance alignments within larger groups. The low completeness of the extracted CG sample is mainly due to the flux limits of the selection criteria. Our results suggest that a new observational algorithm to identify compact groups in redshift space is required to obtain dense isolated galaxy systems.

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Morphological evolution and galactic sizes in the L-Galaxies SA model

Cited by 28 publications

References 242 publications

Using angular momentum maps to detect kinematically distinct galactic components

Using angular momentum maps to detect kinematically distinct galactic components

A tight angular-momentum plane for disc galaxies

Compact groups from semi-analytical models of galaxy formation -- III: purity and completeness of Hickson-like catalogues

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