TheLX‐TandLX‐σ Relationships for Galaxy Clusters Revisited

Wu, Xiang-Ping; Xue, Yan-Jie; Fang, Li‐Zhi

doi:10.1086/307791

Cited by 179 publications

(226 citation statements)

References 82 publications

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“…For each cluster in Col. 8 we indicate the X-ray luminosity in the 0.1−2.4 keV band obtained from the references given in Col. 10 and converted to the cosmology used in this paper. In the case of A1213 the X-ray emission in the 0.5−2 keV band (Ledlow et al 2003) has been converted to the 0.1−2.4 keV band using Table 4 of Böhringer et al (2004), while for CL1446+26 the bolometric X-ray emission (Wu et al 1999) has been converted to the 0.1−2.4 keV band using Table 5 of Böhringer et al (2004). In both cases we assumed an intracluster temperature value T X 5 keV.…”

Section: Discussionmentioning

confidence: 99%

Radio halos in nearby (z < 0.4) clusters of galaxies

Giovannini

Bonafede

Feretti

et al. 2009

A&A

170

263

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Context. The intra-cluster medium is characterized by thermal emission, and by the presence of large scale magnetic fields. In some clusters of galaxies, a diffuse non-thermal emission is also present, located at the cluster center and called radio halo. These sources indicate the existence of relativistic particles and magnetic fields in the cluster volume. Aims. In this paper we collect data on all known nearby cluster radio halos (z < 0.4), to discuss their statistical properties and to investigate their origin. Methods. We searched for published data on radio halos and reduced new and archive VLA data to increase the number of known radio halos.Results. We present data on 31 radio halos, 1 new relic source, and 1 giant filament. We note the discovery of a small size diffuse radio emission in a cluster (A1213) with very low X-ray luminosity. Among the statistical results, we confirm the correlation between the average halo radio spectral index and the cluster temperature. We also discuss the high percentage of clusters where both a relic and a radio halo is present. Conclusions. The sample of radio halos discussed here represents the population of radio halos observable with current radio telescopes. A new telescope generation is necessary for a more detailed multifrequency study, and to investigate the possible existence of a population of radio halos with different properties.

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Section: Discussionmentioning

confidence: 99%

Radio halos in nearby (z < 0.4) clusters of galaxies

Giovannini

Bonafede

Feretti

et al. 2009

A&A

170

263

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“…As a consequence, the stellar (gas) mass fraction should decrease (increase) from groups to clusters, resulting in the increasing mass-to-light ratio and X-ray luminosity with X-ray temperature. It seems that these predictions have been well justified by the optical measurements of the mass-to-light ratios (e.g., Girardi et al 2000) and the X-ray determinations of the gas fractions in clusters (e.g., Mohr, Mathiesen, & Evrard 1999, hereafter MME), and in particular by the discovery of the steepening of the X-ray luminosity (L X )-temperature (T) relation for groups and clusters (Henry & Arnaud 1991;Edge & Stewart 1991;David et al 1993;Wu, Xue, & Fang 1999; and references therein). Nevertheless, despite these apparent successes, such a simple scenario has received less attention over the past years than the prevailing '' preheating '' hypothesis.…”

Section: Introductionmentioning

confidence: 93%

Reexamination of the Galaxy Formation–regulated Gas Evolution Model in Groups and Clusters

Xue

2002

ApJ

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As an alternative explanation of the entropy excess and the steepening of the X-ray luminosity-temperature relation in groups and clusters, the galaxy formation-regulated gas evolution (GG) model proposed recently by Bryan makes an attempt to incorporate the formation of galaxies into the evolution of gas without additional heating by nongravitational processes. This seems to provide a unified scheme for our understanding of the structures and evolution of both galaxies and gas in groups and clusters. In this paper, we present an extensive comparison of the X-ray properties of groups and clusters predicted by the GG model and those revealed by current X-ray observations, using various large data sources in the literature and also taking the observational selection effects into account. These include an independent check of the fundamental working hypothesis of the GG model (i.e., galaxy formation was less efficient in rich clusters than in groups), a new test of the radial gas distributions revealed by both the gas mass fraction and the X-ray surface brightness profiles, and a reexamination of the X-ray luminosity-temperature and entropy-temperature relations. In particular, it shows that the overall X-ray surface brightness profiles predicted by the GG model are very similar in shape and insensitive to the X-ray temperature and that the shallower X-ray surface brightness profiles seen at low-temperature systems may arise from the current observational selection effect. This can be used as the simplest approach to distinguishing between the GG model and the preheating scenario. The latter yields an intrinsically shallower gas distribution in groups than in rich clusters.

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“…CL 1446+26 (or CL 1447+26 or ZwCl 1447.2+2619), is a rich galaxy cluster located at z = 0.370 with an X-ray luminosity 3 in the 0.1−2.4 keV band of 3.41 × 10 44 erg/s (Wu et al 1999). …”

Section: +26mentioning

confidence: 99%

Detection of diffuse radio emission in the galaxy clusters A800, A910, A1550, and CL 1446+26

Govoni¹,

Ferrari²,

Feretti³

et al. 2012

A&A

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Context. Radio halos are elusive sources located at the center of merging galaxy clusters. To date, only about 40 radio halos are known, thus the discovery of new halos provides important insights into this class of sources. Aims. To improve the quality of the statistics of radio halos, we investigate the radio continuum emission of a sample of galaxy clusters. Methods. We analyzed archival Very Large Array observations at 1.4 GHz, with a resolution of 1 . These observations were complemented by X-ray, optical, and higher-resolution radio data, leading to the detection of a new radio halo in the central region of A800 and A1550. We discovered a radio relic in the periphery of A910, and finally revealed both a halo and a relic in CL1446+26. Results. The clusters hosting these new halos show an offset between the radio and the X-ray peak. By analyzing this offset statistically, we find that radio halos can be quite asymmetric with respect to the X-ray gas distribution, with an average radio-X-ray displacement of about 180 kpc. When the offsets are normalized by the halo size, there is a tendency for smaller halos to have larger displacements.

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TheL_X‐TandL_X‐σ Relationships for Galaxy Clusters Revisited

Cited by 179 publications

References 82 publications

Radio halos in nearby (z < 0.4) clusters of galaxies

Radio halos in nearby (z < 0.4) clusters of galaxies

Reexamination of the Galaxy Formation–regulated Gas Evolution Model in Groups and Clusters

Detection of diffuse radio emission in the galaxy clusters A800, A910, A1550, and CL 1446+26

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