Dynamics of clusters of galaxies with central dominant galaxies. I - Galaxy redshifts

Malumuth, E. M.; Kriss, G. A.; Dixon, W. V.; Ferguson, Henry C.; Ritchie, C.

doi:10.1086/116250

Cited by 74 publications

(115 citation statements)

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“…Detailed dynamical studies of the four clusters with signiÐcant peculiar velocities have been reported by Malumuth et al (1992 ;A2052), Oegerle & Hill (1992 ;A2107), this discussion above (A2199), and Bird (1994 ;A2670).…”

Section: Peculiar Velocities Of CD Galaxiesmentioning

confidence: 75%

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Dynamics of [CLC]c[/CLC]D Clusters of Galaxies. IV. Conclusion of a Survey of 25 Abell Clusters

Oegerle

Hill

2001

The Astronomical Journal

149

152

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We present the Ðnal results of a spectroscopic study of a sample of cD galaxy clusters. The goal of this program has been to study the dynamics of the clusters, with emphasis on determining the nature and frequency of cD galaxies with peculiar velocities. Redshifts measured with the MX Spectrometer have been combined with those obtained from the literature to obtain typically 50È150 observed velocities in each of 25 galaxy clusters containing a central cD galaxy. We present a dynamical analysis of the Ðnal 11 clusters to be observed in this sample. All 25 clusters are analyzed in a uniform manner to test for the presence of substructure and to determine peculiar velocities and their statistical signiÐcance for the central cD galaxy. These peculiar velocities were used to determine whether or not the central cD galaxy is at rest in the cluster potential well. We Ðnd that 30%È50% of the clusters in our sample possess signiÐcant subclustering (depending on the cluster radius used in the analysis), which is in agreement with other studies of non-cD clusters. Hence, the dynamical state of cD clusters is not di †erent than that of other present-day clusters. After careful study, four of the clusters appear to have a cD galaxy with a signiÐcant peculiar velocity. Dressler-Shectman tests indicate that three of these four clusters have statistically signiÐcant substructure within 1.5Mpc of the cluster center. The dispersion of the cD h 75 1 peculiar velocities is km s~1 around the mean cluster velocity. This represents a signiÐcant detec-164~3 4 41 tion of peculiar cD velocities but at a level that is far below the mean velocity dispersion for this sample of clusters. The picture that emerges is one in which cD galaxies are nearly at rest with respect to the cluster potential well but have small residual velocities due to subcluster mergers.

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Section: Peculiar Velocities Of CD Galaxiesmentioning

confidence: 75%

“…Redshifts for A2670 have been published by Sharples et al (1988). Redshift data for A85 and A2052 have been published by Malumuth et al (1992). As part of our program, we have previously published data for A2107 (Oegerle & Hill 1992) and A2634 (Pinkney et al 1993).…”

Section: Cluster Samplementioning

confidence: 99%

Dynamics of [CLC]c[/CLC]D Clusters of Galaxies. IV. Conclusion of a Survey of 25 Abell Clusters

Oegerle

Hill

2001

The Astronomical Journal

149

152

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“…The galaxy ESO 243-49 is a member of the cluster Abell 2877 (e.g. Malumuth et al 1992). The vicinity of HLX-1 with ESO 243-49 is confirmed by the redshift of the observed Hα emission line of the counterpart (Wiersema et al 2010), although the velocity offset between this and the bulge of ESO 243-49 is ≈400 km s −1 , close to the escape velocity from the S0 galaxy .…”

Section: Introductionmentioning

confidence: 84%

A disrupted bulgeless satellite galaxy as counterpart of the ultraluminous X-ray source ESO 243-49 HLX-1

Mapelli

Annibali

Zampieri

et al. 2013

A&A

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The point-like X-ray source HLX-1, close to the S0 galaxy ESO 243-49, is one the strongest intermediate-mass black hole candidates, but the nature of its counterpart is still puzzling. By means of N-body/smoothed particle hydrodynamics simulations, we investigate the hypothesis that the HLX-1 counterpart is the nucleus of a bulgeless satellite galaxy, which undergoes a minor merger with the S0 galaxy. We derived synthetic surface brightness profiles for the simulated counterpart of HLX-1 in six Hubble Space Telescope (HST) filters, ranging from far ultraviolet (FUV) to infrared wavelengths, and we compared them with the observed profiles. Our model matches the emission associated with the HLX-1 counterpart in all considered filters, including the bluer ones, even without requiring the contribution of an irradiated disc. The simulation can also account for an extended FUV emission, which is hinted at by the analysis of the F140LP HST filter. This matching is impossible to achieve by assuming either a bulgy satellite, a young star cluster, or an irradiated disc component.

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“…The latter is actually the only galaxy with m r > 21 for which we measured the LOS velocity. The nominal uncertainties given by the cross-correlation algorithm are known to be smaller than the true ones (see, Malumuth et al 1992;Bardelli et al 1994;Ellingson & Yee 1994;Quintana et al 2000). The uncertainties obtained through the RVSAO procedure were multiplied by a factor 2, following previous analyses (Barrena et al 2009, and references therein) on data acquired with the same instrumental setup and with comparable quality or our own.…”

Section: Line Of Sight Velocity Measurementmentioning

confidence: 99%

Fossil group origins

Zarattini¹,

Barrena²,

Girardi³

et al. 2014

A&A

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Context. Virialized halos grow by the accretion of smaller ones in the cold dark matter scenario. The rate of accretion depends on the different properties of the host halo. Those halos for which this accretion rate was very fast and efficient resulted in systems dominated by a central galaxy surrounded by smaller galaxies that were at least two magnitudes fainter. These galaxy systems are called fossil systems, and they can be the fossil relics of ancient galaxy structures. Aims. We started an extensive observational program to characterize a sample of 34 fossil group candidates spanning a broad range of physical properties. Methods. Deep r-band images were obtained with the 2.5-m Isaac Newton Telescope and Nordic Optic Telescope. Optical spectroscopic observations were performed at the 3.5-m Telescopio Nazionale Galileo for ∼1200 galaxies. This new dataset was completed with Sloan Digital Sky Survey Data Release 7 archival data to obtain robust cluster membership and global properties of each fossil group candidate. For each system, we recomputed the magnitude gaps between the two brightest galaxies (Δm 12 ) and the first and fourth ranked galaxies (Δm 14 ) within 0.5 R 200 . We consider fossil systems to be those with Δm 12 ≥ 2 mag or Δm 14 ≥ 2.5 mag within the errors. Results. We find that 15 candidates turned out to be fossil systems. Their observational properties agree with those of non-fossil systems. Both follow the same correlations, but the fossil systems are always extreme cases. In particular, they host the brightest central galaxies, and the fraction of total galaxy light enclosed in the brightest group galaxy is larger in fossil than in non-fossil systems. Finally, we confirm the existence of genuine fossil clusters. Conclusions. Combining our results with others in the literature, we favor the merging scenario in which fossil systems formed from mergers of L * galaxies. The large magnitude gap is a consequence of the extreme merger ratio within fossil systems and therefore it is an evolutionary effect. Moreover, we suggest that at least one fossil group candidate in our sample could represent a transitional fossil stage. This system could have been a fossil in the past, but not now owing to the recent accretion of another group of galaxies.

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Dynamics of clusters of galaxies with central dominant galaxies. I - Galaxy redshifts

Cited by 74 publications

References 0 publications

Dynamics of [CLC]c[/CLC]D Clusters of Galaxies. IV. Conclusion of a Survey of 25 Abell Clusters

Dynamics of [CLC]c[/CLC]D Clusters of Galaxies. IV. Conclusion of a Survey of 25 Abell Clusters

A disrupted bulgeless satellite galaxy as counterpart of the ultraluminous X-ray source ESO 243-49 HLX-1

Fossil group origins

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