Dynamical-friction galaxy-gas coupling and cluster cooling flows

El-Zant, Amr; Kim, Woong-Tae; Kamionkowski, Marc

doi:10.1111/j.1365-2966.2004.08175.x

Cited by 55 publications

(63 citation statements)

References 44 publications

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“…Member galaxies orbiting in the ICM would gradually lose angular momentum to the background ICM, stars, or dark matter through dynamical friction. This effect becomes progressively significant toward the cluster center (El-Zant et al 2004;Gu et al 2013). Given their current positions (possibly within a radius of 5 kpc), these three galaxies are anticipated to sink into the center of the G1 subcluster within a time much shorter than the infall time in a cuspy dark matter halo (Cole et al 2012).…”

Section: The Bcgsmentioning

confidence: 93%

Chandra Observation of Abell 1142: A Cool-Core Cluster Lacking a Central Brightest Cluster Galaxy?

Buote

Gastaldello

et al. 2016

ApJ

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Abell1142 is a low-mass galaxy cluster at low redshift containing two comparable brightest cluster galaxies (BCGs) resembling a scaled-down version of the Coma Cluster. Our Chandra analysis reveals an X-ray emission peak, roughly 100 kpc away from either BCG, which we identify as the cluster center. The emission center manifests itself as a second beta-model surface brightness component distinct from that of the cluster on larger scales. The center is also substantially cooler and more metal-rich than the surrounding intracluster medium (ICM), which makes Abell1142 appear to be a cool-core cluster. The redshift distribution of its member galaxies indicates that Abell1142 may contain two subclusters, each of which contain one BCG. The BCGs are merging at a relative velocity of ≈1200 km s −1 . This ongoing merger may have shock-heated the ICM from ≈2 keV to above 3 keV, which would explain the anomalous L X -T X scaling relation for this system. This merger may have displaced the metal-enriched "cool core" of either of the subclusters from the BCG. The southern BCG consists of three individual galaxies residing within a radius of 5 kpc in projection. These galaxies should rapidly sink into the subcluster center due to the dynamical friction of a cuspy cold dark matter halo.

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Section: The Bcgsmentioning

confidence: 93%

Chandra Observation of Abell 1142: A Cool-Core Cluster Lacking a Central Brightest Cluster Galaxy?

Buote

Gastaldello

et al. 2016

ApJ

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“…Therefore cooling can proceed quickly unless heating mechanisms keep the gas hot, such as adiabatic compression due to a smooth accretion of intergalactic gas onto the halo, shock heating of the ambient gas due to supersonic collisions of infalling gas lumps (e.g. Ryu et al 2003), heating by dynamical friction of supersonic galaxy motions (Ostriker 1999;El-Zant et al 2004), clumpy accretion (Dekel & Birnboim 2008), heating by a background UV field (Haardt & Madau 1996;Hoeft et al 2006), or heating due to feedback mechanisms such as radio mode AGN (Croton et al 2006). The latter is not included in our simulations.…”

Section: The Origin Of the Cold Gasmentioning

confidence: 99%

The Evolution of Central Group Galaxies in Hydrodynamical Simulations

Feldmann

Carollo

Mayer

et al. 2009

ApJ

104

135

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We trace the evolution of central galaxies in three 1013 M sun galaxy groups simulated at high resolution in cosmological hydrodynamical simulations. In all three cases, the evolution in the group potential leads, at z = 0, to central galaxies that are massive, gas-poor early-type systems supported by stellar velocity dispersion and which resemble either elliptical or S0 galaxies. Their z 2-2.5 main progenitors are massive (M * (3-10) × 1010 M sun), star-forming (20-60 M sun yr-1) galaxies which host substantial reservoirs of cold gas ( 5 × 109 M sun) in extended gas disks. Our simulations thus show that star-forming galaxies observed at z 2 are likely the main progenitors of central galaxies in galaxy groups at z = 0. At z 2 the stellar component of all galaxies is compact, with a half-mass radius <1 kpc. The central stellar density stays approximatively constant from such early epochs down to z = 0. Instead, the galaxies grow inside out, by acquiring a stellar envelope outside the innermost 2 kpc. Consequently the density within the effective radius decreases by up to 2 orders of magnitude. Both major and minor mergers contribute to most (70+20 -15%) of the mass accreted outside the effective radius and thus drive an episodical evolution of the half-mass radii, particularly below z = 1. In situ star formation and secular evolution processes contribute to 14+18 -9% and 16+6 -11%, respectively. Overall, the simulated galaxies grow by a factor 4-5 in mass and size since redshift z 2. The short cooling time in the center of groups can foster a "hot accretion" mode. In one of the three simulated groups this leads to a dramatic rejuvenation of the central group galaxy at z < 1, affecting its morphology, kinematics, and colors. This episode is eventually terminated by a group-group merger. Mergers also appear to be responsible for the suppression of cooling flows in the other two groups. Passive stellar evolution and minor galaxy mergers gradually restore the early-type character of the central galaxy in the cooling flow group on a timescale of 1-2 Gyr. Although the average properties of central galaxies may be set by their halo masses, our simulations demonstrate that the interplay between halo mass assembly, galaxy merging, and gas accretion has a substantial influence on the star formation histories and z = 0 morphologies of central galaxies in galaxy groups. Preprint typeset using L A T E X style emulateapj v. 05/04/06 ABSTRACT We trace the evolution of central galaxies in three ∼ 10 13 M galaxy groups simulated at high resolution in cosmological hydrodynamical simulations. THE EVOLUTION OF CENTRAL GROUP GALAXIES IN HYDRODYNAMICAL SIMULATIONSIn all three cases, the evolution in the group potential leads, at z = 0, to central galaxies that are massive, gas-poor early-type systems supported by stellar velocity dispersion and which resemble either elliptical or S0 galaxies. Their z ∼ 2 − 2.5 main progenitors are massive (M * ∼ 3 − 10 × 10 10 M ), star forming (20 − 60M /yr) galaxies which host substantial ...

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“…725 on circular-orbit perturbers provided V p t = 2R p , where R p is the orbital radius. While all the theoretical studies mentioned above consider low-mass perturbers and find various astrophysical applications (e.g., Narayan 2000;El-Zant et al 2004;Kim et al 2005;Kim 2007;Conroy & Ostriker 2008;Villaver & Livio 2009), there are some situations such as in orbital decay of SMBHs or companions in common-envelope binaries, where perturbers have masses so large that the induced density wakes are in the nonlinear regime. Using hydrodynamic simulations, Kim & Kim (2009, hereafter KK09) extended the work of Ostriker (1999) to study nonlinear DF force for a very massive perturber on a straight-line trajectory.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear Dynamical Friction of a Circular-Orbit Perturber in a Gaseous Medium

Kim¹

2010

ApJ

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We use three-dimensional hydrodynamic simulations to investigate the nonlinear gravitational responses of gas to, and the resulting drag forces on, very massive perturbers moving in circular orbits. This work extends our previous studies that explored the cases of low-mass perturbers in circular orbits and massive perturbers on straight-line trajectories. The background medium is assumed to be non-rotating, adiabatic with index 5/3, and uniform with density ρ 0 and sound speed a 0 . We model the gravitating perturber using a Plummer sphere with mass M p and softening radius r s in a uniform circular motion at speed V p and orbital radius R p , and run various models with differing R ≡ r s /R p , M ≡ V p /a 0 , and B ≡ GM p /(a 2 0 R p ). A quasi-steady density wake of a supersonic model consists of a hydrostatic envelope surrounding the perturber, an upstream bow shock, and a trailing low-density region. The continuous change in the direction of the perturber motion reduces the detached shock distance compared to the linear-trajectory cases, while the orbit-averaged gravity of the perturber gathers the gas toward the center of the orbit, modifying the background preshock density to ρ 1 ≈ (1+0.46B 1.1 )ρ 0 depending weakly on M. For sufficiently massive perturbers, the presence of a hydrostatic envelope makes the drag force smaller than the prediction of the linear perturbation theory, resulting in1; the drag force for low-mass perturbers with η B < 0.1 agrees well with the linear prediction. The nonlinear drag force becomes independent of R as long as R < η B /2, which places an upper limit on the perturber size for accurate evaluation of the drag force in numerical simulations.

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Dynamical-friction galaxy-gas coupling and cluster cooling flows

Cited by 55 publications

References 44 publications

Chandra Observation of Abell 1142: A Cool-Core Cluster Lacking a Central Brightest Cluster Galaxy?

Chandra Observation of Abell 1142: A Cool-Core Cluster Lacking a Central Brightest Cluster Galaxy?

The Evolution of Central Group Galaxies in Hydrodynamical Simulations

Nonlinear Dynamical Friction of a Circular-Orbit Perturber in a Gaseous Medium

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