In Frage gestellt

Hopp, Meike; Fleckner, Uwe; Gaehtgens, Thomas W.; Huemer, Christian

doi:10.1515/9783110549300-007

Cited by 7 publications

(14 citation statements)

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“…This could be due to the isothermal temperature of 1.18 keV they assumed, which is biased high by a factor of about 1.2-2 between R 500 and R 200 , and hence M HSE could be biased high. Mass estimations by assuming the optical galaxies in dynamical equilibrium at different characteristic radii are generally larger than our measured M HSE (Huchra & Geller 1982;Hopp & Materne 1985;Ferguson & Sandage 1990). However, the numbers of galaxies used in these measurements are very small (≤ 21), and therefore the statistical uncertainties are quite large.…”

Section: Gas and Hydrostatic Mass Profilesmentioning

confidence: 52%

Suzaku X-Ray Observations of the Nearest Non-Cool Core Cluster, Antlia: Dynamically Young but With Remarkably Relaxed Outskirts

Wong

Irwin

Wik

et al. 2016

ApJ

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We present the results of seven Suzaku mosaic observations (>200 ks in total) of the nearest non-cool core cluster, the Antlia Cluster (or Group), beyond its degree-scale virial radius in its eastern direction. The temperature is consistent with the scaled profiles of many other clusters. Its pressure follows the universal profile. The density slope in its outskirts is significantly steeper than that of the nearest cool core cluster (Virgo) with a similar temperature as Antlia, but shallower than those of the massive clusters. The entropy increases all the way out to R 200 , which is consistent in value with the baseline model predicted by a gravity heating-only mechanism in the outskirts. Antlia is quite relaxed in this direction. However, the entropy inside ∼R 500 is significantly higher than the baseline model, which is similar to many other nearby low mass clusters or groups. The enclosed gas-mass fraction does not exceed the cosmic value out to R 1.3 200 . Thus, there is no evidence of significant gas clumping, electronion non-equipartition, or departure from the hydrostatic equilibrium approximation that are suggested to explain the entropy and gas fraction anomalies found in the outskirts of some massive clusters. We also present scaling relations for the gas fraction ( f gas,200 ), entropy (K 200 ), and temperature (T 500 ) using 22 groups and clusters with published data in the literature. The enclosed baryon fraction at R 200 is broadly consistent with the cosmic value. The power law slope of the K 200 -T 500 relation is 0.638±0.205. The entropy deficit at R 200 cannot be fully accounted for by the bias or deviation in the gas fraction.

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Section: Gas and Hydrostatic Mass Profilesmentioning

confidence: 52%

Suzaku X-Ray Observations of the Nearest Non-Cool Core Cluster, Antlia: Dynamically Young but With Remarkably Relaxed Outskirts

Wong

Irwin

Wik

et al. 2016

ApJ

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“…The system of NGC 3268 is somewhat poorer, but is still typical of a giant elliptical galaxy, with almost 5000 globular clusters (Bassino et al 2008). Hopp & Materne (1985) and, more recently, Hess et al (2015) estimated velocity dispersions of ∼ 500 km s −1 for the bright population of Antlia, higher than those in clusters like Fornax (Drinkwater et al 2001). The globular cluster luminosity function indicated that NGC 3258 could be a few Mpc nearer than NGC 3268 (Dirsch et al 2003b;Bassino et al 2008), which agrees with the distances obtained with surface brightness fluctuations by Blakeslee et al (2001).…”

Section: Introductionmentioning

confidence: 98%

“…The character of the galaxy assembly in the constellation of Antlia is not as clear as, for example, in the cases of the Virgo or Fornax galaxy clusters. Some authors used the term "galaxy group" (Ferguson & Sandage 1990), others "galaxy cluster" (Hopp & Materne 1985;Smith Castelli et al 2008), and Hopp & Materne (1985) identified five "clusters" in the Antlia region (α = 10 h − 10 h 50 m , δ = −42 o − −30 o ). The most striking central cluster is called "Antlia II".…”

Section: Introductionmentioning

confidence: 99%

Deconstructing the Antlia cluster core

Caso

Richtler

2015

A&A

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Context. The present literature does not give a satisfactory answer to the question about the nature of the "Antlia galaxy cluster". Aims. The radial velocities of galaxies found in the region around the giant ellipticals NGC 3258/3268 range from about 1000 km s −1 to 4000 km s −1 . We characterise this region and its possible kinematical and population substructure. Methods. We have obtained VLT-VIMOS multi-object spectra of the galaxy population in the inner part of the Antlia cluster and measure radial velocities for 45 potential members. We supplement our galaxy sample with literature data, ending up with 105 galaxy velocities.Results. We find a large radial velocity dispersion for the entire sample as reported in previous papers. However, we find three groups at about 1900 km s −1 , 2800 km s −1 , and 3700 km s −1 , which we interpret as differences in the recession velocities rather than peculiar velocities. Conclusions. The high radial velocity dispersion of galaxies in the Antlia region reflects a considerable extension along the line of sight.

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“…The cluster is relatively massive, with an estimated virial mass of around 5 × 10 14 M (e.g. Hopp & Materne 1985;Hess et al 2015). Antlia contains ∼ 375 galaxy members, with a galaxy density around 1.7 times higher than Virgo and 1.4 times higher than Fornax (Ferguson & Sandage 1990).…”

Section: Introductionmentioning

confidence: 99%

“…Antlia contains ∼ 375 galaxy members, with a galaxy density around 1.7 times higher than Virgo and 1.4 times higher than Fornax (Ferguson & Sandage 1990). At its centre, the Antlia cluster hosts two main concentrations of galaxies surrounding the massive ellipticals NGC 3268 and NGC 3258, but contains at least five subclusters in total (Hopp & Materne 1985). The elongated galaxy and X-ray distribution of the Antlia cluster is indicative of a cluster in an intermediate merger state (e.g.…”

Section: Introductionmentioning

confidence: 99%

Large Molecular Gas Reservoirs in Star-forming Cluster Galaxies

Cairns

Stroe

Breuck

et al. 2019

ApJ

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We present CO(2-1) observations of 72 galaxies in the nearby, disturbed Antlia galaxy cluster with the Atacama Pathfinder Experiment (APEX) telescope. The galaxies in our sample are selected to span a wide range of stellar masses (10 8 M M 10 10 M ) and star formation rates (0.0005 M yr −1 < SFR < 0.3 M yr −1 ). Reaching a depth of 23 mJy in 50 km s −1 channels, we report a total CO detection rate of 37.5% and a CO detection rate of 86% for sources within 1 dex of the main sequence. We compare our sample with a similar sample of galaxies in the field, finding that, for a fixed stellar mass and SFR, galaxies in the Antlia cluster have comparable molecular gas reservoirs to field galaxies. We find that ∼ 41% (11/27) of our CO detections display non-Gaussian CO(2-1) emission line profiles, and a number of these sources display evidence of quenching in their optical images. We also find that the majority of our sample lie either just below, or far below the main sequence of field galaxies, further hinting at potential ongoing quenching. We conclude that the Antlia cluster represents an intermediate environment between fields and dense clusters, where the gentler intracluster medium (ICM) allows the cluster members to retain their reservoirs of molecular gas, but in which the disturbed ICM is just beginning to influence the member galaxies, resulting in high SFRs and possible ongoing quenching.

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In Frage gestellt

Cited by 7 publications

References 0 publications

Suzaku X-Ray Observations of the Nearest Non-Cool Core Cluster, Antlia: Dynamically Young but With Remarkably Relaxed Outskirts

Suzaku X-Ray Observations of the Nearest Non-Cool Core Cluster, Antlia: Dynamically Young but With Remarkably Relaxed Outskirts

Deconstructing the Antlia cluster core

Large Molecular Gas Reservoirs in Star-forming Cluster Galaxies

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