Substructure and Dynamics of the Fornax Cluster

Drinkwater, Michael J.; Gregg, Michael D.; Colless, Matthew

doi:10.1086/319113

Cited by 236 publications

(381 citation statements)

References 22 publications

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“…NGC 1404, an elliptical galaxy with km s~1 p g D 150 (Winsall & Freeman 1993), appears to be falling into the core of the Fornax group, which has km s~1 p c D 370 (Drinkwater, Gregg, & Colless 2001). The infall velocity of the system is (Ferguson 1989). Using the X-ray M Z 1.1 data of Jones et al (1997), we predict dS/S D kpc) in the FDM model, where is the 0.12È0.15(r c /125 r c assumed core radius of the group.…”

Section: Surface Brightness Mapsmentioning

confidence: 99%

Constraining the Collisional Nature of the Dark Matter through Observations of Gravitational Wakes

Furlanetto

Loeb

2002

ApJ

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We propose to use gravitational wakes as a direct observational probe of the collisional nature of the dark matter. We calculate analytically the structure of a wake generated by the motion of a galaxy in the core of an X-ray cluster for dark matter in the highly collisional and collisionless limits. Although the di †erence between these limits is most likely too subtle to be detected with weak lensing observations, we show that the two cases can be distinguished through detailed X-ray observations. We also discuss the sizes of subhalos in these limits. Preliminary X-ray data on the motion of NGC 1404 through the Fornax group disfavors Ñuidlike dark matter but does not exclude scenarios in which the dark matter is weakly collisional.

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Section: Surface Brightness Mapsmentioning

confidence: 99%

Constraining the Collisional Nature of the Dark Matter through Observations of Gravitational Wakes

Furlanetto

Loeb

2002

ApJ

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“…In this framework, we are performing a deep, multiband (u, g, r, and i) survey of the nearby Fornax cluster at the VLT Survey Telescope (VST), situated at the Paranal observatory of the European Southern Observatory (ESO). The Fornax Deep Survey (FDS) with VST aims to cover the whole Fornax cluster out to the virial radius (Drinkwater et al 2001), with an area of about 26square degrees around the central galaxy NGC1399, including the region where NGC1316 is located. The FDS will provide an unprecedented view of the structures of the cluster members, ranging from giant early-type galaxies to small spheroidal galaxies.…”

Section: Introductionmentioning

confidence: 99%

THE FORNAX DEEP SURVEY WITH VST. I. THE EXTENDED AND DIFFUSE STELLAR HALO OF NGC 1399 OUT TO 192 kpc

Iodice

Capaccioli

Grado

et al. 2016

ApJ

170

342

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We have started a new, deep multi-imaging survey of the Fornax cluster, dubbed the Fornax Deep Survey (FDS), at the VLT Survey Telescope (VST). In this paper we present the deep photometry inside two square degrees around the bright galaxy NGC1399 in the core of the cluster. We found that the core of the Fornax cluster is characterized by a very extended and diffuse envelope surrounding the luminous galaxy NGC1399: we map the surface brightness out to 33 arcmin (∼192 kpc) from the galaxy center and down to μ g ∼31 mag arcsec −2 in the g band. The deep photometry allows us to detect a faint stellar bridge in the intracluster region on the west side of NGC1399 and toward NGC1387. By analyzing the integrated colors of this feature, we argue that it could be due to the ongoing interaction between the two galaxies, where the outer envelope of NGC1387 on its east side is stripped away. By fitting the light profile, we found that there exists a physical break radius in the total light distribution at R=10 arcmin (∼58 kpc) that sets the transition region between the bright central galaxy and the outer exponential halo, and that the stellar halo contributes 60% of the total light of the galaxy (Section 3.5). We discuss the main implications of this work on the build-up of the stellar halo at the center of the Fornax cluster. By comparing with the numerical simulations of the stellar halo formation for the most massive bright cluster galaxies (i.e., M M 13 log 14, we find that the observed stellar halo mass fraction is consistent with a halo formed through the multiple accretion of progenitors with stellar mass in the range 10 8 -10 11 M e . This might suggest that the halo of NGC1399 has also gone through a major merging event. The absence of a significant number of luminous stellar streams and tidal tails out to 192 kpc suggests that the epoch of this strong interaction goes back to an early formation epoch. Therefore, different from the Virgo cluster, the extended stellar halo around NGC1399 is characterized by a more diffuse and well-mixed component, including the intracluster light.

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“…Although NGC 1399 shows some evidence of merging (e.g. Drinkwater et al 2001), it appears to be just starting to merge so only the outer regions have been affected. It is also possible that the galaxy NGC 1404 has disturbed the core as it fell in.…”

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confidence: 99%

What is a cool-core cluster? a detailed analysis of the cores of the X-ray flux-limitedHIFLUGCScluster sample

Hudson¹,

Mittal

Reiprich³

et al. 2010

A&A

425

597

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We use the largest complete sample of 64 galaxy clusters (HIghest X-ray FLUx Galaxy Cluster Sample) with available high-quality X-ray data from Chandra, and apply 16 cool-core diagnostics to them, some of them new. In order to identify the best parameter for characterizing cool-core clusters and quantify its relation to other parameters, we mainly use very high spatial resolution profiles of central gas density and temperature, and quantities derived from them. We also correlate optical properties of brightest cluster galaxies (BCGs) with X-ray properties. To segregate cool core and non-cool-core clusters, we find that central cooling time, t cool , is the best parameter for low redshift clusters with high quality data, and that cuspiness is the best parameter for high redshift clusters. 72% of clusters in our sample have a cool core (t cool < 7.7 h −1/2 71 Gyr) and 44% have strong cool cores (t cool < 1.0 h −1/2 71 Gyr). We find strong cool-core clusters are characterized as having low central entropy and a systematic central temperature drop. Weak cool-core clusters have enhanced central entropies and temperature profiles that are flat or decrease slightly towards the center. Non-cool-core clusters have high central entropies.For the first time we show quantitatively that the discrepancy in classical and spectroscopic mass deposition rates can not be explained with a recent formation of the cool cores, demonstrating the need for a heating mechanism to explain the cooling flow problem. We find that strong cool-core clusters have a distribution of central temperature drops, centered on 0.4T vir . However, the radius at which the temperature begins to drop varies. This lack of a universal inner temperature profile probably reflects the complex physics in cluster cores not directly related to the cluster as a whole. Our results suggest that the central temperature does not correlate with the mass of the BCGs and weakly correlates with the expected radiative cooling only for strong cool-core clusters. Since 88% of the clusters in our sample have a BCG within a projected distance of 50 h −1 71 kpc from the X-ray peak, we argue that it is easier to heat the gas (e.g. with mergers or non-gravitational processes) than to separate the dense core from the brightest cluster galaxy. Diffuse, Mpc-scale radio emission, believed to be associated with major mergers, has not been unambiguously detected in any of the strong cool-core clusters in our sample. Of the weak cool-core clusters and non-cool-core clusters, most of the clusters (seven out of eight) that have diffuse, Mpc-scale radio emission have a large (>50 h −1 71 kpc) projected separation between their BCG and X-ray peak. In contrast, only two of the 56 clusters with a small separation between the BCG and X-ray peak (<50 h −1 71 kpc) show large-scale radio emission. Based on this result, we argue that a large projected separation between the BCG and the X-ray peak is a good indicator of a major merger. The properties of weak cool-core clusters as an intermedi...

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Substructure and Dynamics of the Fornax Cluster

Cited by 236 publications

References 22 publications

Constraining the Collisional Nature of the Dark Matter through Observations of Gravitational Wakes

Constraining the Collisional Nature of the Dark Matter through Observations of Gravitational Wakes

THE FORNAX DEEP SURVEY WITH VST. I. THE EXTENDED AND DIFFUSE STELLAR HALO OF NGC 1399 OUT TO 192 kpc

What is a cool-core cluster? a detailed analysis of the cores of the X-ray flux-limitedHIFLUGCScluster sample

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