Contraction of dark matter galactic halos due to baryonic infall

“Adiabatic contraction (Blumenthal et al. 1986), instead, is able to increase the amount of dark matter in the centers of ellipticals and to lower the required stellar masses toward a Kroupa IMF (see also Napolitano et al. 2011).”

“…– formally equivalent to the requirement that the angular momentum is conserved, condition that identifies the adiabatic invariant M(R)R (Blumenthal et al. 1986) – is that the orbital time of DM particles should be short with respect to the gravitational potential variation time…”

“…although less secure observationally (Humphrey et al. 2006; Gnedin et al. 2007; Napolitano et al. 2010), is so-called “adiabatic contraction” (Blumenthal et al. 1986; Gnedin et al. 2004; Abadi et al. 2009), where the DM halo density profile reacts to the gravitational influence of baryons…”

“…matter plays an essential role, which is in agreement with the conclusions of Burkert et al. (2010), who concluded that adiabatic contraction (e.g. Blumenthal et al. 1986) of the halo due to baryonic infall is problematic, as it predicts halo spin parameters λ that are significantly higher than…”

“…gas collides, shocks, mixes, and eventually dissipates energy via radiative cooling, causing it to collapse to the minimum of a halo’s potential well and seed the formation of stars and galaxies (White & Rees 1978; Fall & Efstathiou 1980; Blumenthal et al. 1986; Dubinski 1994; Mo et al. 1998).”

“That seven out of the ten EELs with well-constrained dark matter properties have inner halo slopes that are significantly steeper than NFW suggests that these haloes may have been strongly contracted due to the inital cooling and infall of baryons (Blumenthal et al. 1986; Gnedin et al. 2004).”

“The question of how a dark matter halo will respond to the growth of mass in its center has been adressed by Blumenthal et al. (1986), hereafter B86.”

“This phenomenology, acting on the dark matter component mainly in proximity of the host halo centre and known as adiabatic contraction (Blumenthal et al. 1986; Rix et al. 1997; Keeton 2001; Gnedin et al. 2011).”

“For example, the baryons that condense toward the center of DM halos can compress DM by adiabatic contraction (Blumenthal et al. 1986; Mo et al. 1998).”

“As a comparison, Jiang & Kochanek (2007) measure a ∼30% decrease in stellar M/L ratio by including the Blumenthal et al. (1986) AC model on a subsample of lower-redshift strong lenses, in good agreement with the results we see when we increase the inner slope of the NFW profile by ∼20%.”

“Here we discuss halo density profiles within the context of adiabatic approximation models (e.g., Blumenthal et al. 1986; Ryden & Gunn 1987; Gnedin et al. 2004).”

“The effect of baryons on the cluster mass distribution is unclear, but may be significant in the inner cluster regions (Blumenthal et al. 1986; Gnedin et al. 2004; Naab et al. 2007; Rudd, Zentner & Kravtsov 2008; Zentner, Rudd & Hu 2008; Barkana & Loeb 2010).”

“We assume that angular momentum is conserved and that the self-gravity of the collapsing baryons causes the inner part of the halo to contract (Blumenthal et al. 1986; Flores et al. 1993; Mo, Mao & White 1998).”

“Initially, the baryons and dark matter share the same angular momentum distribution and the baryons conserve angular momentum as they collapse, creating a rotation-supported disk (Fall & Efstathiou 1980; Blumenthal et al. 1986; Mo et al. 1998).”

“…the model considers the effects of non-radial collapse originated by random angular momentum15, adiabatic contraction of DM that baryons produce (Blumenthal et al. 1986; Gnedin et al. 2004; Gustafsson et al. 2006), dynamical friction effects (e.g., El-Zant et al. 2001, 2004), random and ordered…”

“…of DM halos, clusters are observed to cool relatively inefficiently via thermal emission so that the gas remains close to the virial temperature, making cluster mass profiles easy to interpret, as corrections for gas cooling are not significant (Blumenthal et al. 1986; Broadhurst & Barkana 2008).”

“Kregel et al. (2005) argued that the analytical collapse model of disc galaxy formation (White & Rees 1978; Fall & Efstatiou 1980; Blumenthal et al. 1986; Mo, Mao & White 1998), the local Toomre’s (1964) stability criterion for a disc and the suggestion about vertical dynamical equilibrium,…”

“5 kpc from the GC), they fell short by 1 order of magnitude, which they argue could be compensated by a more spiky profile resulting from baryon cooling effects known as adiabatic contraction [120, 121, 122].”

“DM and stellar mass distributions have been found to interact with each other through processes such as dissipational collapse, in which the infall of baryonic matter compresses the DM halo (Blumenthal et al. 1986).”

“We refrain from including prescriptions for the effects of baryonic contraction on our halo model (e.g. Blumenthal et al. 1986; Gnedin et al. 2004; Abadi et al. 2009).”

“In addition, for the sake of simplicity we disregard the influence of the baryons on the halo structure in terms of adiabatic contractions or expansions (see Blumenthal et al. 1986; Gnedin et al. 2004).”

“On the other hand, some steepening of the inner density profile may be induced by any ‘adiabatic’ contraction of the diffuse star-forming baryons into a disc-like structure, as proposed by Blumenthal et al. (1986) and Mo, Mao & White (1998).”

“On smaller, galaxy-mass scales (corresponding to of a few arcseconds), the test is complicated by the presence of cooled baryons; when baryons cool and condense into a galaxy, they modify the surrounding dark matter halo (e.g., Blumenthal et al. 1986).”

“New radii are computed for the disc and bulge by applying an adiabatic contraction of the disc, bulge and dark matter components (Blumenthal et al. 1986; Jesseit, Naab & Burkert 2002).”

“4 show the profiles one obtains when one starts with the three isolated halos and applies to these objects the classic adiabatic contraction formalism of Blumenthal et al. (1986).”

“The models presented in this article neglect adiabatic contraction but we have made the experiment to run our default model with adiabatic contraction modeled as in Blumenthal et al. (1986).”

“2 kpcDM 200=1.88 × 1010 M in the most extreme case (Blumenthal et al. 1986), or a lower value of M3.”

“Di Cintio et al. (2011) showed that the inclusion of baryons has a twofold effect, inreasing or decreasing its central density according to an adiabatic contraction (Blumenthal et al. 1986) or outflows (Navarro et al.1996; Governato et al. 2012) model.”

“This process is usually referred to as the adiabatic contraction (AC) model (Blumenthal et al. 1986; Zel’dovich et al. 1980; Jesseit et al. 2002; Gnedin et al. 2004; Prada et al. 2004).”

“Lovell et al. (2018) find that for ∼ 1012 M IllustrisTNG halos, adiabatic contraction (Blumenthal et al. 1986; Gnedin et al. 2004) is present from the inner most regions of the galaxies out to 20 kpc, whereas halo expansion at small radii for similar Illustris halos occur.”

“For example, in the absence of feedback-driven outflows, the slow growth of a central galaxy may deepen the gravitational potential adiabatically, resulting in a contraction of DM in the innermost regions of a halo (Blumenthal et al. 1986).”

“Blumenthal et al. (1986) showed that dissipative baryons will lead directly to the adiabatic contraction of the halo increasing its central density, thus being a critical ingredient to determine subhalo properties.”

“Today, a basic framework exists to describe the formation of galaxies from primordial fluctuations in the density field (White and Rees, 1978; Blumenthal et al., 1986; White and Frenk, 1991).”

“One such effect is the adiabatic contraction of DM by the slow addition of baryons to the center of the potential well (Blumenthal et al. 1986).”

“…are plain and simple: while it is well established that baryonic physics alters the particulars of dark matter haloes and subhalo populations (Blumenthal et al. 1986; Tissera & Dominguez-Tenreiro 1998; Macciò et al. 2006; Oñorbe et al. 2007; Romano-Dı́az et al. 2008, 2009; Libeskind et al.…”

“In response to the slow addition of baryons to the center, dark matter may be pulled in- wards through a process known as adiabatic contraction (Blumenthal et al. 1986; Gnedin et al. 2004; Pillepich et al. 2014).”

“We use the adiabatic compression model (Blumenthal et al. 1986) to compute the changes in the dark matter distribution.”

“However, numerical simulations find that dark matter does not fully respond to the baryonic infall according to the theoretical model of Blumenthal et al. (1986) (e.g., Gnedin et al., 2004; Abadi et al., 2010).”

“…second case, the gas radiates away its orbital and thermal energy and is responsible for the adiabatic contraction of the dark matter halo, i.e., for a central density profile steeper with respect to the initial distribution (e.g., Blumenthal et al. 1986; Jesseit et al. 2002; Gnedin et al. 2004).”

“…based on the initial angular momentum of the gas and the halo profile, assuming that angular momentum is conserved and that the self-gravity of the collapsing baryons causes contraction of the matter in the inner part of the halo (Blumenthal et al. 1986; Flores et al. 1993; Mo, Mao & White 1998).”

“The possibility that baryons might influence the structureformation process and, in particular, the DM distribution, was introduced almost three decades ago with the development of the analytic model of “adiabatic contraction” (Barnes & White 1984; Blumenthal et al. 1986; Ryden & Gunn 1987).”

“…galaxies and can alter the initial distribution of dark matter in numerous ways: through gas expulsion (Navarro et al. 1996), supernova driven impulsive heating (Pontzen & Governato 2011), AGN feedback (Duffy et al. 2010) or adiabatic contraction (Blumenthal et al. 1986; Gnedin et al. 2004, 2011).”

“…Kormendy (1985) argues that these two populations mayactually be the same type of galaxies. c© 2009 RAS density in UCDs would be two orders of magnitude too low to explain their elevatedM/LV ratios, although adiabatic contraction (Blumenthal et al. 1986) may alleviate this problem (Murray 2009).”

“E-mail: frizzo@mpa-garching.mpg.de within a galaxy (e.g. Blumenthal et al. 1986; Dutton et al. 2011; Courteau & Dutton 2015; Zolotov et al. 2015).”

“The process is also accompanied by the adiabatic contraction of the dark matter halo (Blumenthal et al. 1986).”

“The DM component responds to the baryon sinking through an adiabatic contraction effect, leading to a further increase of the concentration (Blumenthal et al. 1986).”

“In particular, the condensation of gas and stars can produce an adiabatic contraction of the DM halo, increasing the central DM density [37, 38].”

“…investigation of such processes have been undertaken, some pointing out effects that would increase the gradient of the density cusp still further (Blumenthal et al. 1986), some discussing processes that could p - tentially remove the cusp (Binney et al. 2001; El-Zant et al.2001; Weinberg & Katz…”

“One possibility is for the DM to contract adiabatically (Blumenthal et al. 1986; Gnedin et al. 2004, 2011), but it is also possible for baryons to transfer energy to the halo and cause it to expand instead (e.g. Macciò et al. 2012; Di Cintio et al. 2014; Pontzen & Governato 2014).”

“…inflows during the process of galaxy formation is to slowly drag dark matter toward the galaxy centre, in a process known as adiabatic contraction (Blumenthal et al. 1986; Gnedin et al. 2011), which renders the centre of dark matter haloes more concentrated than what is found in N-body only…”

“On the cores of these structures, luminous matter dynamics is indeed the main agent, acting through the interplay of halo contraction associated with cooling and expansion associated with feedback effects (Blumenthal et al. 1986; Keeton 2001; Gnedin et al. 2004).”

“In contrast, when going from γ dm = 1 without AC to including AC, the cross-section increases by a factor of ∼2.6 for the Blumenthal et al. (1986) prescription, or a factor of ∼2.0 for the Gnedin et al. (2004) prescription.”

“The present form of the adiabatic compression model was numerically and analytically studied by Blumental et al [43].”

“Following the early work by Barnes & White (1984), Blumenthal et al. (1986) devised a simple formula to link the dark mass profiles before and after the assembly of a galaxy.”

“In our modeling, the effect of contraction of the dark matter halo due to disk formation (Blumenthal et al. 1986; Gnedin et al. 2004; Choi et al. 2006) is ignored.”

“We calculate the response of the mass distribution of the galaxy to the infall of cold gas following the adiabatic contraction recipe of Blumenthal et al. (1986), which is stronger than more recent ones based on numerical simulations (e.g. Gnedin et al. 2004).”