Orbital parameters of merging dark matter halos

By S. Khochfar, A. Burkert. 2003

137 citations recorded by the source corpus.

In order to specify cosmologically motivated initial conditions for major galaxy mergers (mass ratios ≤ 4:1) that are supposed to explain the formation of elliptical galaxies we study the orbital parameters of major mergers of cold dark matter halos using a high-resolution cosmological simulation. Almost half of all encounters are nearly parabolic with eccentricities $e \approx 1$ and no correlations between the halo spin planes or the orbital planes. The pericentric argument ω shows no correlation with the other orbital parameters and is distributed randomly. In addition we find that 50% of typical pericenter distances are larger than half the halo's virial radii which is much larger than typically assumed in numerical simulations of galaxy mergers. In contrast to the usual assumption made in semi-analytic models of galaxy formation the circularities of major mergers are found to be not randomly distributed but to peak around a value of $\epsilon \approx 0.5$. Additionally all results are independent of the minimum progenitor mass and major merger definitions (i.e. mass ratios ≤ 4:1; 3:1; 2:1).

Subfields: Astronomy and Astrophysics, Instrumentation, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/06037b2c468231964c01c5f59cee7dab1adf8bd9

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Instrumentation

In Nuclear and High Energy Physics

Citations in the corpus

Properties of Early-Type, Dry Galaxy Mergers and the Origin of Massive Elliptical Galaxies (2005, background): “Khochfar & Burkert (2003) and Khochfar & Burkert (2005, hereafter KB05) used semianalytical modeling to demonstrate that massive elliptical galaxies should have assembled predominantly in mergers between bulge-dominated, gas-poor (dry) early-type galaxies.”
The effect of galaxy mass ratio on merger-driven starbursts (2007, background): “The resulting interactions are fast and nearly radial, consistent with orbits found for dark matter halos in cosmological simulations (Vitvitska et al. 2002; Khochfar & Burkert 2006; Benson 2005; Zentner et al. 2005).”
Feedback in simulations of disc-galaxy major mergers (2005, background): “This generates a fast, nearly radial, collision consistent with orbits found for dark-matter halos in a cosmological simulation (Khochfar & Burkert 2006).”
MINOR MERGERS AND THE SIZE EVOLUTION OF ELLIPTICAL GALAXIES (2009, unknown): “Assuming energy conservation (orbital parameters from cosmological simulations (Khochfar & Burkert 2006) indicate that most halos merge on parabolic orbits), the total energy of the final system is Ef = Ei + Ea = − 1 2 Mi〈v 2 i 〉 − 1 2 Ma〈v 2 a〉 = − 1 2 Mi〈v 2 i 〉 − 1 2 ηMiǫ〈v 2 i 〉 = − 1 2 Mi〈v 2…”
The role of minor mergers in the recent star formation history of early-type galaxies (2007, methodology): “In all simulations satellites are put on prograde parabolic orbits (Khochfar & Burkert 2006), with a pericentric distance Rp = 8 kpc, and initial separations of 100 kpc.”
The influence of gas on the structure of merger remnants (2006, unknown): “A study of orbits of merging dark matter halos in cosmological large scale simulations by Khochfar & Burkert (2006) has shown that a significant number of the merging halos are indeed on parabolic orbits with a broad distribution of pericenter distances.”
Post-starburst galaxies: more than just an interesting curiosity (2008, background): “The galaxies approach each other on parabolic orbits, which are generally motivated by statistics from N-body simulations (Khochfar & Burkert 2006).”
Simulations of minor mergers - I. General properties of thick discs (2008, background): “Benson determined the orbital parameters of DM substructures at the time they crossed the virial radius of their host halos (see also Tormen 1997; Khochfar & Burkert 2006).”
GAMA: towards a physical understanding of galaxy formation (2009, background): “Fortunately, the predictions for these timescales from high-resolution simulations of specific galaxy merger scenarios (e.g. Khochfar and Burkert 2006) are now quite robust and suggest that both timescales are of order 0.5–2 Gyr.”
Red mergers and the assembly of massive elliptical galaxies: the fundamental plane and its projections (2006, methodology): “…boxy isophotal shapes with increasing stellar mass in elliptical galaxies suggests an increasing fraction of dissipationless mergers in the growth of the most massive elliptical galaxies (e.g. Bender, Burstein & Faber 1992; Kormendy & Bender 1996; Faber et al. 1997; Naab, Khochfar & Burkert 2006).”
Dark Matter Substructure in Numerical Simulations: A Tale of Discreteness Noise, Runaway Instabilities, and Artificial Disruption (2018, background): “Although the fraction of subhaloes/satellite galaxies on purely circular orbits is vanishingly small (e.g. Zentner et al. 2005; Khochfar & Burkert 2006; Wetzel 2011; van den Bosch 2017), and realistic host haloes are not static in that they respond dynamically to the presence of the subhalo, these…”
Simulations of binary galaxy mergers and the link with fast rotators, slow rotators, and kinematically distinct cores (2011, background): “Owing to large statistical samples, modern work tends to quantify in detail the properties of major and minor merger remnants, together with thorough comparisons with observed properties of ETGs (Naab & Burkert 2003; Bournaud, Combes & Jog 2004; Bournaud, Jog & Combes 2005; Naab, Jesseit & Burkert 2”
A Simple Model for the Size Evolution of Elliptical Galaxies (2006, methodology): “On the other hand, many stellar dynamical properties of elliptical galaxies can be explained by the merger of similar massive galaxies (e.g. Barnes & Hernquist 1992; Naab & Burkert 2003; Naab, Jesseit & Burkert 2006) as initially proposed by Toomre & Toomre (1972).”
THE COSMOLOGICAL SIZE AND VELOCITY DISPERSION EVOLUTION OF MASSIVE EARLY-TYPE GALAXIES (2011, background): “Assuming energy conservation and parabolic orbits (Benson 2005; Khochfar & Burkert 2006) the final gravitational radius of the system is given by Rg,f Rg,i = (1 + η)2 (1 + ηǫ) , (1) where Rg,i and Rg,f are the initial and final gravitational radii (before and after the merger event) which we assume…”
Theoretical Challenges in Galaxy Formation (2016, background): “Depending on the mass-ratio of the merging disks - and the amount of ’damage’ that is done to the primary disk, the remnants rotate fast or slow, have disky, round or boxy isophotal shapes and are more or less flattened (Barnes 1998; Bekki 1998; Bendo & Barnes 2000; Bournaud, Combes & Jog 2004; Bour”
THE MAJOR AND MINOR GALAXY MERGER RATES AT z < 1.5 (2011, background): “Large-scale numerical simulations find that the majority of dark-matter halo mergers are parabolic as opposed to circular (Khochfar & Burkert 2006; Benson 2005; Wetzel 2010), with only modest evolution in the typical orbital eccentricity out to z ∼ 1.5 (Wetzel 2010).”
Growth and activity of black holes in galaxy mergers with varying mass ratios (2014, background): “We set the initial separation Rinit to be equal to the sum of the two initial virial radii, and the c© 0000 RAS, MNRAS 000, 000–000 first pericentric distance Rperi to be equal to 20 per cent (Khochfar & Burkert 2006) of the initial virial radius of G1, defined in Section 2.2.”
Dynamical friction and galaxy merging time-scales (2007, methodology): “Full dynamical models of the evolution of merging halos – complete with the physics of dynamical friction, tidal stripping, and gravitational shocking – have been created by a number of groups (e.g., Taylor & Babul 2001; Taffoni et al. 2003; Zentner et al. 2005; Gnedin 2003).”
Structure and Kinematics of Early-Type Galaxies from Integral Field Spectroscopy (2016, background): “…Ostriker 1978), one can show that during a gas-free merger of identical spherical galaxies on parabolic orbits, which is the most likely situation (Khochfar & Burkert 2006), the radius grows proportionally to the mass and the galaxy stellar velocity dispersion (integrated over the whole galaxy)…”