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Testing the key role of the stellar mass-halo mass relation in galaxy merger rates and morphologies via DECODE, a novel Discrete statistical sEmi-empiriCal mODEl

Fu, Hao and Shankar, Francesco and Ayromlou, Mohammadreza and Dickson, Max and Koutsouridou, Ioanna and Rosas-Guevara, Yetli and Marsden, Christopher and Brocklebank, Kristina and Bernardi, Mariangela and Shiamtanis, Nikolaos and Williams, Joseph and Zanisi, Lorenzo and Allevato, Viola and Boco, Lumen and Bonoli, Silvia and Cattaneo, Andrea and Dimauro, Paola and Jiang, Fangzhou and Lapi, Andrea and Menci, Nicola and Petropoulou, Stefani and Villforth, Carolin (2022) Testing the key role of the stellar mass-halo mass relation in galaxy merger rates and morphologies via DECODE, a novel Discrete statistical sEmi-empiriCal mODEl. Monthly Notices of the Royal Astronomical Society, 516 (3). pp. 3206-3233. ISSN 0035-8711. doi:10.1093/mnras/stac2205.

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The relative roles of mergers and star formation in regulating galaxy growth are still a matter of intense debate. We here present our DECODE, a new Discrete statistical sEmi-empiriCal mODEl specifically designed to predict rapidly and efficiently, in a full cosmological context, galaxy assembly, and merger histories for any given input stellar mass–halo mass (SMHM) relation. DECODE generates object-by-object dark matter merger trees (hence discrete) from accurate subhalo mass and infall redshift probability functions (hence statistical) for all subhaloes, including those residing within other subhaloes, with virtually no resolution limits on mass or volume. Merger trees are then converted into galaxy assembly histories via an input, redshift-dependent SMHM relation, which is highly sensitive to the significant systematics in the galaxy stellar mass function and on its evolution with cosmic time. DECODE can accurately reproduce the predicted mean galaxy merger rates and assembly histories of hydrodynamic simulations and semi-analytical models, when adopting in input their SMHM relations. In this work, we use DECODE to prove that only SMHM relations implied by stellar mass functions characterized by large abundances of massive galaxies and significant redshift evolution, at least at M_* ≳ 10^(11) M_⊙⁠, can simultaneously reproduce the local abundances of satellite galaxies, the galaxy (major merger) pairs since z ∼ 3, and the growth of Brightest Cluster Galaxies. The same models can also reproduce the local fraction of elliptical galaxies, on the assumption that these are strictly formed by major mergers, but not the full bulge-to-disc ratio distributions, which require additional processes.

Item Type:Article
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URLURL TypeDescription
Shankar, Francesco0000-0001-8973-5051
Ayromlou, Mohammadreza0000-0003-3783-2321
Marsden, Christopher0000-0002-7993-6228
Jiang, Fangzhou0000-0001-6115-0633
Additional Information:We warmly thank Philip J. Grylls for reading the manuscript, and for useful discussion and comments. We thank the referee for a careful reading of the manuscript and for useful inputs. We also thank Sergio Contreras for useful discussions. This work received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 860744. HF acknowledges partial support from the ‘Torno Subito’ programme. MA acknowledges funding from the Deutsche Forschungsgemeinschaft (DFG) through an Emmy Noether Research Group (grant number NE 2441/1-1). YRG acknowledges the support of the ‘Juan de la Cierva Incorporation’ fellowship (IC2019-041131-I).
Funding AgencyGrant Number
Marie Curie Fellowship860744
Deutsche Forschungsgemeinschaft (DFG)NE 2441/1-1
Juan de la Cierva FellowshipIC2019-041131-I
Issue or Number:3
Record Number:CaltechAUTHORS:20220928-285212100.14
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:117169
Deposited By: Melissa Ray
Deposited On:04 Oct 2022 21:11
Last Modified:04 Oct 2022 21:11

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