Galaxy-induced transformation of dark matter haloes: Transformations of CDM haloes

“We adopt cosmological parameters consistent with the combined analysis of the 2dfGRS (Colless et al., 2001) and the first-year WMAP data (Spergel et al., 2003): a present day value of the Hubble constant of H0 = 70 km/s/Mpc; a scalefree initial density perturbation spectrum with no tilt and…”

“The DMO mass profile is shown by the thick red solid curve and, as expected, it is well approximated by the NFW (Navarro et al., 1996b, 1997) formula (thin solid line).”

“The DMO mass profile is shown by the thick red solid curve and, as expected, it is well approximated by the NFW (Navarro et al., 1996b, 1997) formula (thin solid line).”

“Each dot in this panel correspond to an NFW halo with concentration drawn at random from the mass-concentration relation (including scatter) derived by Neto et al. (2007) from the Millennium Simulation (Springel et al., 2005).”

“…formation have adopted this formulation in order to link the (observed) dynamical properties of luminous galaxies to the (predicted) properties of the dark halos that surround them (see, e.g., Mo et al., 1998; Cole et al., 2000; Dutton et al., 2005; Croton et al., 2006; Somerville et al., 2008).”

“The virial density contrast, ∆vir(z) is given by ∆vir(z) = 18π 2 + 82f(z) − 39f(z)2, where f(z) = [Ω0(1 + z)3/(Ω0(1 + z)3 + ΩΛ))] − 1 and Ω0 = ΩCDM + Ωb(Bryan & Norman, 1998).”

“We adopt cosmological parameters consistent with the combined analysis of the 2dfGRS (Colless et al., 2001) and the first-year WMAP data (Spergel et al., 2003): a present day value of the Hubble constant of H0 = 70 km/s/Mpc; a scalefree initial density perturbation spectrum with no tilt and…”

“…formation have adopted this formulation in order to link the (observed) dynamical properties of luminous galaxies to the (predicted) properties of the dark halos that surround them (see, e.g., Mo et al., 1998; Cole et al., 2000; Dutton et al., 2005; Croton et al., 2006; Somerville et al., 2008).”

“When baryons are included, the halos become more spherical and evolve toward oblate at all radii but mostly in their inner parts (e.g., Kazantzidis et al. 2004, Bailin et al. 2005, Abadi et al. 2010).”

“Remaining effects of baryons on halo potential wells (e.g., making them less triaxial; Abadi et al. 2010) are more difficult to observe, and may require higher-order statistics such as three-point functions to capture.”

“However, recent simulations suggest that this simple scheme overestimates the effect (e.g. Gnedin et al. 2004; Abadi et al. 2010).”

“At the same time, several recent studies showed that no single set of parameters of such simple models describes all objects that form in cosmological simulations equally well(Abadi et al. 2010; Gnedin et al. 2011; Gustafsson, Fairbairn & Sommer-Larsen 2006; Tisseraet al. 2010).”

“…expected from the effect of adiabatic contraction galaxies with significant in-situ star formation, i.e. more dissipation, live in more concentrated halos (Blumenthal et al. 1986; Dubinski 1994; Jesseit et al. 2002; Debattista et al. 2008; Gnedin et al. 2004; Abadi et al. 2010; Auger et al. 2010).”

“In addition, since the inner part of dark matter halos is actually populated by baryons that collapse through dissipative processes, dark halos should contract, thus exacerbating any preexisting cusp (Blumenthal et al. 1986; Gnedin et al. 2004; Abadi et al. 2010).”

“Nonetheless, individual haloes can deviate from the mean prediction since the size of the contraction is weakly dependent on the assembly history of the system (e.g. Abadi et al. 2010; Artale et al. 2019).”

“Nonetheless, individual haloes can deviate from the mean prediction since the size of the contraction is weakly dependent on the assembly history of the system (e.g. Abadi et al. 2010; Artale et al. 2019).”

“In this approach the tension between the constraints coming from the circular speed at the solar radius, and the mass estimates at larger distances are likely to be resolved by an intermediate halo model as proposed by Abadi et al. (2010).”

“The halo inner logarithmic slope is allowed to vary from the values predicted by halo contraction models (Abadi et al. 2010) to the nearly constant density profiles expected from halo expansion models (Pontzen & Governato 2012).”

“…modify the structure of the DM. Cooling allows baryons to condense toward the center, which makes the DM more concentrated (Blumenthal et al. 1986; Gnedin et al. 2004; Sellwood & McGaugh 2005; Gustafsson et al. 2006; Pedrosa et al. 2009; Abadi et al. 2010; Sommer-Larsen & Limousin 2010).”

“However, these triaxial structures become approximately oblate when baryonic physics is included in the simulations (see, e.g. Abadi et al. 2010), with c/a ∼ 0.8, c/b ∼ 0.9 for the dark matter component, at a radial distance corresponding to ∼ 30 kpc in M31 (Zemp et al. 2012, see their Figure 11).”

“…formed in the galaxy (e.g., the adiabatic contraction, or AC, models of Blumenthal et al. 1986; Gnedin et al. 2004, hereafter B86 and G04) or dynamical friction may counterbalance this effect (Abadi et al. 2009) and could result in cored profiles (e.g., El-Zant et al. 2004; Nipoti et al. 2004).”

“2008; Abadi et al. 2009).”

“[25, 26] showed that a better agreement with numerical simulations is obtained if the slightly modified relation”

“If one defines the initial radius of each dark matter shell as ri and its final, adiabatically contracted value rf , Abadi et al. (2009) have proposed to capture Gnedin et al. (2004) model using the following simplified model: rf ri = 1 + α ( Mi Mf − 1 ) with α 0.68.”

“…should be much more frequent than major mergers and are therefore expected (see e.g. Khochfar & Silk 2006; Naab et al. 2007; Bournaud, Jog & Combes 2007; Genel et al. 2008, 2010; Naab, Johansson & Ostriker 2009; Hopkins et al. 2010; Oser et al. 2010; Qu et al. 2010; Abadi et al. 2010, CDM models).”

“…of a galactic baryonic disk causes the halos to become more axisymmetric and aligned with the disk, but the minor-to-major axis ratio c/a changes only by a few tenths to c/a ≈ 0.7 to 0.8 (Dubinski 1994; Gustafsson et al. 2006; Debattista et al. 2008; Abadi et al. 2010; Kazantzidis et al. 2010).”

“[33] found best agreement with simulations for the values of a = 0.”

“It is obviously sensible to take the fullest possible advantage of existing constraints on the Galaxy’s mass distribution when selecting mass models.”

“…Gustafsson, Fairbairn & Sommer-Larsen 2006; Duffy et al. 2010; Tissera et al. 2010), spins (e.g. Bett et al. 2010; Bryan et al. 2013), shapes (e.g. Abadi et al. 2010; Kazantzidis et al. 2004; Read et al. 2008; Bryan et al. 2012, 2013), and substructure (e.g. Dolag et al. 2009; Romano-Dı́az et al.…”

“This result is in qualitative agreement with many theoretical studies of the evolution of spheroidal galaxies (Blumenthal et al. 1986; Gnedin et al. 2004; Gustafsson et al. 2006; Abadi et al. 2010; Duffy et al. 2010).”

“However, the work of Tissera et al. (2010); Abadi et al. (2010); Bett et al. (2010) shows that even though the halo axis ratios c© 2011 RAS, MNRAS 000, 1–11 increase when a disc is formed (i.e. they become rounder), the trends with radius appear to be preserved.”

“2006; Abadi et al. 2010; Deason et al. 2011). However, since these studies used different sized haloes or simulations that had different feedback effects, it is difficult to make direct comparisons. For example Kazantzidis et al. (2004) ran Adaptive Refinement Tree N -body + hydrodynamic simulations of cluster sized h…”

“Simulations with baryons find that the central galaxy tends to make the triaxial halo essentially oblate and less flattened (e.g., Abadi et al. 2010).”

“The effect of baryons on the structure of haloes has been studied extensively, both using analytical models (e.g. Blumenthal et al. 1986; Sellwood & McGaugh 2005) and in numerical simulations (e.g. Abadi et al. 2010; Duffy et al. 2010; Bryan et al. 2012).”

“We compare the results of our hydrodynamical runs at z = 0 with the prediction of a simple adiabatic contraction model used by Abadi et al. (2010), and already adopted in Teyssier et al. (2011); details of this model can be found in Appendix A.”

“…is not the case for SDIG, whose paltry peak rotation speed is just Vout ∼ 19 km/s, well below the V Pout ∼ 30 km/s expected at the outermost radius, rout = 1.3 kpc. ‡ The prediction assumes an NFW halo contracted to account for the effect of the baryonic component following Abadi et al. (2010).”

“…literature, both from the theoretical (Gnedin et al. 2004; Gustafsson et al. 2006; Romano-Dı́az et al. 2008; Johansson et al. 2009; Duffy et al. 2010; Abadi et al. 2010; Pedrosa et al. 2010; Tissera et al. 2010; Governato et al. 2010; Guedes et al. 2011; Gnedin et al. 2011) and observational sides…”

“…to a steepening of the DM density profile of DM haloes due to adiabatic contraction (Blumenthal et al. 1986; Gnedin et al. 2004), in agreement with previous works (e.g., Gustafsson et al. 2006; Romano-Díaz et al. 2008 Abadi et al. 2010; Pedrosa et al. 2010; Tissera et al. 2010; Duffy et al. 2010).”

“…tends to increase the central angular momentum of the halo (see for example, Sharma & Steinmetz 2005; Tonini et al. 2006a; Kaufmann et al. 2007; Abadi et al. 2010; Bett et al. 2010) and to make the halo more spherical or axisymmetric (see, for example, Katz & Gunn 1991; Dubinski 1994; Evrard…”

“Note however, that inclusion of baryons (see e.g. Kazantzidis et al. 2004; Gnedin et al. 2004; Debattista et al. 2008; Abadi et al. 2010) or adaptation of a different Dark Matter model (e.g. Avila-Reese et al. 2001; ? giorio@ast.cam.ac.uk † vasily@ast.cam.ac.uk Davé et al. 2001; Mayer et al. 2002;…”

“High-resolution, cosmological N -body + gas dynamical simulations of galaxy clusters (Gnedin et al. 2004) and galaxies (Gustafsson et al. 2006; Abadi et al. 2009, but see Romano-Dı́az et al. 2008) have shown that as baryons condense in the center, they deepen the potential and steepen the dark…”

“…because simulated DM halos are much more flattened (〈c/a〉 ≃ 0.5, Jing & Suto 2002) than stars in elliptical galaxies (〈c/a〉 ≃ 0.7, Tremblay & Merritt 1995), and because isotropic dissipation processes in the baryon-dominated regime should yield rounder mass distributions (e.g., Abadi et al. 2010).”

“Abadi et al. (2010) employ galaxy models which include radiative gas cooling but neglect the contribution from stellar feedback.”

“For instance, the dark matter distribution is often assumed to follow the NFW profile or the NFW profile modified by the so-called adiabatic contraction (Blumenthal et al. 1986; Gnedin et al. 2004; Abadi et al. 2010).”

“See also Dubinski (1994); Kazantzidis et al. (2004); Debattista et al. (2008); Valluri et al. (2010); Abadi et al. (2010); and Romano-Diaz et al. (2009), who studied halo shapes in a cosmological context and found that the response of the DM to baryonic condensation into galaxies drives the halos…”

“This similarity occurs despite the absence of stellar and AGN feedback in Abadi et al. (2010), which accentuates the effect of baryons.”

“We explore the sensitivity of our results to these assumptions by doing the analyses with the following alternatives: a) AC recipes of varying strengths (Blumenthal et al. 1986, B+86; Abadi et al. 2010, A+10); b) Mvir with a fixed value for the entire sample: Mvir = 10 12M⊙, 10 13M⊙, or 10 14M⊙; c) WMAP3based cvir–Mvi…”

“Previous determinations indicated that there was less dark matter mass than predicted by cosmological simulations within R0 (Navarro & Steinmetz 2000; Binney et al. 2000; Famaey & Binney 2005; Abadi et al. 2010), whilst our determination would imply that there is more dark matter mass inside R0.”

“Gas cooling permits baryons to condense in the central regions of galaxies, and therefore it is believed to make the mass distribution more centrally concentrated (e.g. Gnedin et al. 2004; Gustafsson et al. 2006; Abadi et al. 2010; Velliscig et al. 2014).”

“Dissipation in baryonic simulations can make the highly triaxial halos seen in dark matter only simulations more spherical (Dubinski 1994; Kazantzidis et al. 2004; Debattista et al. 2008; Kazantzidis et al. 2010; Abadi et al. 2010).”

“…contraction (Blumenthal et al. 1986) corresponds to ν = 1, the contraction model of Gnedin et al. (2004) can be approximated with ν ≃ 0.8, the contraction model of Abadi et al. (2010) can be approximated with ν ≃ 0.4, an unmodified halo corresponds to ν = 0, while expansion corresponds to ν < 0.”

“Recent numerical work(see, e.g., Abadi et al. 2010; Tissera et al. 2010) has shown that including the contribution of the baryons has the effect of modifying the overall profile of the dark halo, which flattens to a more axisymmetric and oblate shape, with an average axial ratio of order 0.85−0.95,…”

“…processes associated with them have been shown to significantly impact, for example, the mass profiles (e.g. Gnedin et al. 2004, Duffy et al. 2010, Abadi et al. 2010, Governato et al. 2012, Martizzi et al. 2012, Velliscig et al. 2014) and shapes of haloes (e.g. Kazantzidis et al. 2004, Tissera et…”

“However, recent work predicts only mild contraction for star formation efficiencies compatible with observations (Dutton et al. 2007; Abadi et al. 2010; Schaller et al. 2014) and also a counteracting expansion due to feedback (Navarro, Eke & Frenk 1996; Pontzen & Governato 2012).”

“CDM haloes are also found to be more prolate at smaller radii (Allgood et al. 2006; Macciò et al. 2008; Abadi et al. 2010).”

“…simulations of galaxy formation often find much weaker contraction than predicted by the adiabatic contraction formalism (Johansson et al. 2009; Abadi et al. 2010; Tissera et al. 2010) or even expansion (Governato et al. 2010; Macciò et al. 2012), and thus we do not actually expect adiabatic…”

“…both for the dynamical inference of the shape of the DM halo (see e.g. Williams & Evans 2015b; Bowden et al. 2016) and for our understanding of the response of the DM distribution to the presence of baryons (see Kazantzidis et al. 2004; Gnedin et al. 2004; Duffy et al. 2010; Abadi et al. 2010).”

“…either plagued by the so called overcooling problem (which produced galaxies that were unrealistically dominated by baryons in their central region Kazantzidis et al. 2004) or were missing important aspects of the galaxy formation process such as star formation and feedback (Abadi et al. 2010).”

“However, baryons can make the CDM halo shapes more spherical (red) (see also, Dubinski 1994; Debattista et al. 2008; Kazantzidis et al. 2010; Abadi et al. 2010; Tissera et al. 2010), an effect partially attributed to the change of orbits from boxy to tube or rounder loop as a result of the central…”

“Contracting a halo with c200 = 15., towards the upper end of the cosmological values, with the prescription of Abadi et al. (2010) results in rotation curves just consistent with the microlensing results here.”

“…the mass distribution, we find that the slope η ≈ 0.823 of the basic SISSA model is steepened to the value 0.958 according to the prescription for halo contraction by Blumenthal et al. (1986), to 0.920 according to that by Gnedin et al. (2004), and to 0.877 according to that by Abadi et al. (2010).”

“While the concentration cV is only sensitive to the matter distribution within rmax, the processes of gas cooling and star formation affect the dark matter profile throughout the whole halo (see also Rudd et al. 2008; Abadi et al. 2010).”

“…with a tendency towards oblateness (Kazantzidis et al. 2004; Kazantzidis, Abadi & Navarro 2010; Bailin et al. 2005; Berentzen & Shlosman 2006; Gustafsson, Fairbairn & Sommer-Larsen 2006; Debattista et al. 2008; Tissera et al. 2010; Machado & Athanassoula 2010; Abadi et al. 2010; Lau et al. 2011).”

“The radial dependence of dark matter halo shapes has previously been studied using N -body simulations (e.g., Allgood et al. 2006; Schneider, Frenk & Cole 2012) and smallvolume hydrodynamic simulations (e.g., Kazantzidis et al. 2004; Abadi et al. 2010; Deason et al. 2011).”

“The 𝑠 parameter is motivated by baryonic processes that can bias the concentration of baryons within the dark 1 https://github.com/SandyYuan/GRAND-HOD matter potential well (e.g. Duffy et al. 2010; Abadi et al. 2010; Chua et al. 2017; Peirani et al. 2017).”

“Furthermore, the central galaxy is expected to sphericalise the dark matter haloes (e.g. Kazantzidis et al. 2010; Abadi et al. 2010; Machado & Athanassoula 2010).”

“As reported in earlier work (see, e.g. Navarro & Steinmetz 1997; Abadi et al. 2010), the angular momentum of each component rises quickly with time until turnaround and stays roughly constant or declines slightly thereafter.”

“These measurements are essential for studies of the Galaxy in the contexts of galaxy evolution and cosmology (Abadi et al. 2010; Boylan-Kolchin et al. 2010; Wang et al. 2012) and to the analysis of the 6D motions of high-velocity stars in the tails of the velocity distribution and the local escape…”

“It has been shown in hydrodynamical simulations that baryonic processes modify 1 Available from http://www-astro.physics.ox.ac.uk/∼mxc/software c© 2015 RAS, MNRAS 000, 1–14 the inner profile of the dark halo (Abadi et al. 2010).”

“…stars in the Galatic halo are thought to have been accreted from dwarf galaxies at early epochs, based on cosmological hydrodynamical simulations of the Local Group (Ibata et al. 1994; Helmi et al. 1999; Ibata et al. 2004; Abadi et al. 2010; Starkenburg et al. 2017a; El-Badry et al. 2018).”

“…Blumenthal et al. 1986), which might allow lower stellar mass normalization by dragging more DM into the central regions (see e.g. Napolitano, Romanowsky & Tortora 2010), as these seem to be disfavoured by both simulations (e.g. Abadi et al. 2010) and observational studies (e.g. Auger et al. 2010).”

“8 in Abadi et al. 2010).”

“Indeed, radiative hydrodynamic simulations with baryonic cooling have been found to produce haloes that are both more spherical and centrally concentrated (e.g. Gnedin et al. 2004; Abadi et al. 2010).”

“…dissipative condensation of baryons can induce a transformation of the structure of dark haloes to a more oblate and axisymmetric shape in the inner regions while preserving their triaxial shape in the outer parts (Debattista et al. 2008; Abadi et al. 2010; Valluri et al. 2010; Bryan et al. 2012).”