Hot gas and dark matter in a compact galaxy group

Ponman, T. J.; Bertram, D. S.

doi:10.1038/363051a0

Cited by 111 publications

(107 citation statements)

References 25 publications

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“…In this case too the goodness-of-fit criteria point toward the choice of the Sérsic model with only a few borderline cases and more than 40 out of 46 cases strongly in favor of the latter. However, most of the derived β parameter values are compatible with those typical of the ICM in galaxy groups (see, e.g., Ponman & Bertram 1993) and clusters (e.g., Mohr & Evrard 1997), which span the range from β ∼ 0.5 to β ∼ 0.65 ( Figure 6). The integrated Sérsic profile was able to correctly reproduce most of the observed profiles, but the presence of some luminosity bumps in the profiles of some clusters resulted in some poor fits.…”

Section: Profile Fitting and Effective Parameters Calculationmentioning

confidence: 61%

Characterization of Omega-WINGS galaxy clusters

Cariddi

D’Onofrio

Fasano

et al. 2018

A&A

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Context. Galaxy clusters are the largest virialized structures in the observable Universe. Knowledge of their properties provides many useful astrophysical and cosmological information. Aims. Our aim is to derive the luminosity and stellar mass profiles of the nearby galaxy clusters of the Omega-WINGS survey and to study the main scaling relations valid for such systems. Methods. We merged data from the WINGS and Omega-WINGS databases, sorted the sources according to the distance from the brightest cluster galaxy (BCG), and calculated the integrated luminosity profiles in the B and V bands, taking into account extinction, photometric and spatial completeness, K correction, and background contribution. Then, by exploiting the spectroscopic sample we derived the stellar mass profiles of the clusters. Results. We obtained the luminosity profiles of 46 galaxy clusters, reaching r 200 in 30 cases, and the stellar mass profiles of 42 of our objects. We successfully fitted all the integrated luminosity growth profiles with one or two embedded Sérsic components, deriving the main clusters parameters. Finally, we checked the main scaling relation among the clusters parameters in comparison with those obtained for a selected sample of early-type galaxies (ETGs) of the same clusters. Conclusions. We found that the nearby galaxy clusters are non-homologous structures such as ETGs and exhibit a color-magnitude (CM) red-sequence relation very similar to that observed for galaxies in clusters. These properties are not expected in the current cluster formation scenarios. In particular the existence of a CM relation for clusters, shown here for the first time, suggests that the baryonic structures grow and evolve in a similar way at all scales.

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Section: Profile Fitting and Effective Parameters Calculationmentioning

confidence: 61%

Characterization of Omega-WINGS galaxy clusters

Cariddi

D’Onofrio

Fasano

et al. 2018

A&A

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“…Later, Ponman & Bertram (1993) and Ponman et al (1994) studied HCG 62 and RX J1340.6+1018, finding that compact groups of galaxies form as a result of the orbital decay of galaxies into an extended dark matter halo. Finally, massive galaxies in these systems merge with the central group galaxy as a result of dynamical friction, forming a system known as a fossil group.…”

Section: Composite Luminosity Functionmentioning

confidence: 99%

“…For this to be a viable formation scenario, we expect fossil groups to present a luminosity function (LF) with a deficit of L * galaxies. The key lies in the timescale for the merging of dwarf galaxies and cooling group X-ray halo (Ponman & Bertram 1993;Ponman et al 1994), which is much longer than the timescale for the merging of more luminous galaxies. The final product of these mergers are present day isolated ellipticals, which are immersed in group size X-ray halos and surrounded by substantially fainter galaxies (e.g.…”

Section: Introductionmentioning

confidence: 99%

Evolution of the galaxy luminosity function in progenitors of fossil groups

Gozaliasl

Khosroshahi

Dariush

et al. 2014

A&A

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Using the semi-analytic models based on the Millennium simulation, we trace back the evolution of the luminosity function of galaxies residing in progenitors of groups classified by the magnitude gap at redshift zero. We determine the luminosity function of galaxies within 0.25 R 200 , 0.5 R 200 , and R 200 for galaxy groups/clusters. The bright end of the galaxy luminosity function of fossil groups shows a significant evolution with redshift, with changes in M * by ∼1−2 mag between z ∼ 0.5 and z = 0 (for the central 0.5 R 200 ), suggesting that the formation of the most luminous galaxy in a fossil group has had a significant impact on the M * galaxies e.g. it is formed as a result of multiple mergers of M * galaxies within the last 5 Gyr. In contrast, the slope of the faint end, α, of the luminosity function shows no considerable redshift evolution and the number of dwarf galaxies in the fossil groups exhibits no evolution, unlike in non-fossil groups where it grows by ∼25−42% towards low redshifts. In agreement with previous studies, we also show that fossil groups accumulate most of their halo mass earlier than non-fossil groups. Selecting the fossils at a redshift of 1 and tracing them to a redshift 0, we show that 80% of the fossil groups (10 13 M h −1 < M 200 < 10 14 M h −1 ) will lose their large magnitude gap. However, about 40% of fossil clusters (M 200 > 10 14 M h −1 ) will retain their large gaps.

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“…Available X-ray data suggest that poor groups have a lower fraction of hot gas than do rich clusters of galaxies; the mass of hot gas is approximately ten times smaller than the stellar mass (Ponman & Bertram 1993, Pildis, Bregman, & Evrard 1995. According to X-ray data dark matter extends significantly beyond the apparent configuration of bright galaxies in good agreement with optical data on the distribution of faint companion galaxies; the total massto-luminosity ratio is in agreement with optical data, M/L B ≈ 120 h M ⊙ /L ⊙ (Ponman & Bertram 1993).…”

Section: Poor Groups Of Galaxiesmentioning

confidence: 99%

Dark Matter in Groups and Clusters of Galaxies

Einasto

2000

International Astronomical Union Colloquium

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Abstract.We compare the characteristics of stellar populations with those of dark halos. Dark matter around galaxies, and in groups, clusters and voids is discussed. Modern data suggest that the overall density of matter in the Universe is Ω M = 0.3 ± 0.1, about 80 % of this matter is nonbaryonic dark matter, and about 20 % is baryonic, mostly in the form of hot intra-cluster and intragroup gas, the rest in stellar populations of galaxies. All bright galaxies are surrounded by dark matter halos of external radii 200 − 300 kpc; halos consist mostly of non-baryonic matter with some mixture of hot gas. The Universe is dominated by dark energy (cosmological constant) term. Dark matter dominates in the dynamical evolution of galaxies in groups and clusters.

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Hot gas and dark matter in a compact galaxy group

Cited by 111 publications

References 25 publications

Characterization of Omega-WINGS galaxy clusters

Characterization of Omega-WINGS galaxy clusters

Evolution of the galaxy luminosity function in progenitors of fossil groups

Dark Matter in Groups and Clusters of Galaxies

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