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2016-09

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Please use this identifier to cite or link to this item: https://hdl.handle.net/2445/127654

Forming first-ranked early-type galaxies through hierarchical dissipationless merging

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https://doi.org/10.1093/mnras/stw1278

Abstract

We have developed a computationally competitive N-body model of a previrialized aggregation of galaxies in a flat Λ cold dark matter Universe to assess the role of the multiple mergers that take place during the formation stage of such systems in the configuration of the remnants assembled at their centres. An analysis of a suite of 48 simulations of low-mass forming groups (Mtot,gr ∼ 1013 h−1 M⊙) demonstrates that the gravitational dynamics involved in their hierarchical collapse is capable of creating realistic first-ranked galaxies without the aid of dissipative processes. Our simulations indicate that the brightest group galaxies (BGGs) constitute a distinct population from other group members, sketching a scenario in which the assembly path of these objects is dictated largely by the formation of their host system. We detect significant differences in the distribution of Sérsic indices and total magnitudes, as well as a luminosity gap between BGGs and the next brightest galaxy that is positively correlated with the total luminosity of the parent group. Such gaps arise from both the grow of BGGs at the expense of lesser companions and the decrease in the relevance of second-ranked objects in equal measure. This results in a dearth of intermediate-mass galaxies which explains the characteristic central dip detected in their luminosity functions in dynamically young galaxy aggregations. The fact that the basic global properties of our BGGs define a thin mass Fundamental Plane strikingly similar to that followed by giant early-type galaxies in the local Universe reinforces confidence in the results obtained.

Subject

Formació de les galàxies, Matèria fosca (Astronomia)

Subject (English)

Galaxy formation, Dark matter (Astronomy)

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Articles publicats en revistes (Física Quàntica i Astrofísica)
Articles publicats en revistes (Institut de Ciències del Cosmos (ICCUB))

Citation

SOLANES, José M. (José María), et al. Forming first-ranked early-type galaxies through hierarchical dissipationless merging. Monthly Notices of the Royal Astronomical Society. 2016. Vol. 461, num. 1, pags. 321-343. ISSN 0035-8711. [consulted: 11 of August of 2026]. Available at: https://hdl.handle.net/2445/127654

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