Detailed Mass Map of CL 0024+1654 from Strong Lensing

Tyson, J. A.; Kochanski, Greg; Dell’Antonio, Ian

doi:10.1086/311314

Cited by 308 publications

(350 citation statements)

References 22 publications

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“…The value of the core radius r c is somewhat uncertain. It is zero in the original NFW model, but cluster lensing studies (Tyson et al 1998;Shapiro & Iliev 2000) suggest that it may be tens of kiloparsecs in some clusters. As explained in x 3, we try two values of r c : r c ¼ 0 and r c ¼ r s =20.…”

Section: The Modelmentioning

confidence: 99%

Models of Galaxy Clusters with Thermal Conduction

Zakamska

Narayan

2003

ApJ

215

306

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We present a simple model of hot gas in galaxy clusters, assuming hydrostatic equilibrium and energy balance between radiative cooling and thermal conduction. For five clusters, A1795, A1835, A2199, A2390, and RX J1347.5À1145, the model gives a good description of the observed radial profiles of electron density and temperature, provided that we take the thermal conductivity to be about 30% of the Spitzer conductivity. Since the required is consistent with the recent theoretical estimate of Narayan & Medvedev for a turbulent magnetized plasma, we consider a conduction-based equilibrium model to be viable for these clusters. We further show that the hot gas is thermally stable because of the presence of conduction. For five other clusters, A2052, A2597, Hydra A, Ser 159-03, and 3C 295, the model requires unphysically large values of to fit the data. These clusters must have some additional source of heat, possibly an active galactic nucleus, since all the clusters have strong radio galaxies at their centers. We suggest that thermal conduction, although not dominant in these clusters, may nevertheless play a significant role by preventing the gas from becoming thermally unstable.

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Section: The Modelmentioning

confidence: 99%

Models of Galaxy Clusters with Thermal Conduction

Zakamska

Narayan

2003

ApJ

215

306

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“…There has been a debate about whether the inner density profile of simulated clusters really approaches an asymptote of the form / r À1 (e.g., Fukushige & Makino 1997;Moore et al 1999;Jing & Suto 2000;Power et al 2003;Fukushige et al 2004) and whether such a density cusp is consistent with observed clusters (e.g., Tyson et al 1998;Smith et al 2001;Ettori et al 2002;Kelson et al 2002;Sand et al 2002Sand et al , 2004Lewis et al 2003). Our main need is for a model other than the isothermal ellipsoid that we can apply to massive clusters and low-mass dwarf halos.…”

Section: Definitionsmentioning

confidence: 99%

Gravitational Lensing Magnification without Multiple Imaging

Keeton

Kuhlen

Haiman

2005

ApJ

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Gravitational lensing can amplify the apparent brightness of distant sources. Images that are highly magnified are often part of multiply imaged systems, but we consider the possibility of having large magnifications without additional detectable images. In rare but nonnegligible situations, lensing can produce a single highly magnified image; this phenomenon is mainly associated with massive cluster-scale halos (k10 13.5 M ). Alternatively, lensing can produce multiply imaged systems in which the extra images are either unresolved or too faint to be detectable. This phenomenon is dominated by galaxies and lower mass halos (P10 12 M ) and is very sensitive to the inner density profile of the halos. Although we study the general problem, we customize our calculations to four quasars at redshift z % 6 in the Sloan Digital Sky Survey (SDSS), for which Richards et al. (2004) have ruled out the presence of extra images down to an image splitting of Á ¼ 0B3 and a flux ratio of f ¼ 0:01. We predict that 9%-29% of all z % 6 quasars that are magnified by a factor of > 10 would lack detectable extra images, with 5%-10% being true singly imaged systems. The maximum of 29% is reached only in the unlikely event that all low-mass (P10 10 M ) halos have highly concentrated (isothermal) profiles. In more realistic models in which dwarf halos have flatter (Navarro-Frenk-White) inner profiles, the maximum probability is $10%. We conclude that the probability that all four SDSS quasars are magnified by a factor of 10 is P10 À4 . The only escape from this conclusion is if there are many (>10) multiply imaged z % 6 quasars in the SDSS database that have not yet been identified, which seems unlikely. In other words, lensing cannot explain the brightnesses of the z % 6 quasars, and models that invoke lensing to avoid having billion-solar-mass black holes in the young universe are not viable.

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“…However, a series of observations of dark matter structures on the order of < ∼ 1 Mpc (e.g., galaxy rotation curves [2,3,4], strong lensing from galaxy clusters [5], Tully-Fisher relation of spiral galaxies [6], bar stability in spirals [7,8] and deficit of low-mass subhalos in the Local Group [9]) appear to contradict the prediction of collisionless CDM simulations that dark matter halos form high-density cores, favoring shallower, lower-density dark matter halo cores.…”

Section: Introductionmentioning

confidence: 99%

“…Potential difficulties for this model may arise at cluster scales [13,5,14,15]; one way to address these would be a velocity-dependent cross section, the effect of which we will consider below.…”

Section: Introductionmentioning

confidence: 99%

Constraining strong baryon–dark-matter interactions with primordial nucleosynthesis and cosmic rays

et al. 2002

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Self-interacting dark matter (SIDM) was introduced by Spergel & Steinhardt to address possible discrepancies between collisionless dark matter simulations and observations on scales of less than 1 Mpc. We examine the case in which dark matter particles not only have strong self-interactions but also have strong interactions with baryons. The presence of such interactions will have direct implications for nuclear and particle astrophysics. Among these are a change in the predicted abundances from big bang nucleosynthesis (BBN) and the flux of γ-rays produced by the decay of neutral pions which originate in collisions between dark matter and Galactic cosmic rays (CR).From these effects we constrain the strength of the baryon-dark matter interactions through the ratio of baryon -dark matter interaction cross section to dark matter mass, s. We find that BBN places a weak upper limit to this ratio < ∼ 10 8 cm 2 g −1 . CR-SIDM interactions, however, limit the possible DM-baryon cross section to < ∼ 5 × 10 −3 cm 2 g −1 ; this rules out an energy-independent interaction, but not one which falls with center-of-mass velocity as s ∝ 1/v or steeper.

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Detailed Mass Map of CL 0024+1654 from Strong Lensing

Cited by 308 publications

References 22 publications

Models of Galaxy Clusters with Thermal Conduction

Models of Galaxy Clusters with Thermal Conduction

Gravitational Lensing Magnification without Multiple Imaging

Constraining strong baryon–dark-matter interactions with primordial nucleosynthesis and cosmic rays

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