J0454-0309: evidence of a strong lensing fossil group falling into a poor galaxy cluster

Schirmer, M.; Suyu, S. H.; Schrabback, T.; Hildebrandt, Hendrik; Erben, T.; Halkola, A.

doi:10.1051/0004-6361/200913810

Cited by 21 publications

(18 citation statements)

References 94 publications

(160 reference statements)

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“…This second system, however, must be lacking in bright galaxies otherwise the magnitude gap would vanish and the system would no longer qualify as an FS, making this mode of formation unlikely, yet not impossible. Schirmer et al (2010) found J0454-0309 to consist of two systems, a sparse cluster and an infalling FS, the latter they believe will seed the FG. They also find, outside a radius of 1.5 Mpc, two filaments that extend over 4 Mpc.…”

Section: Discussionmentioning

confidence: 98%

THEXMMCLUSTER SURVEY: THE STELLAR MASS ASSEMBLY OF FOSSIL GALAXIES

Harrison

Miller

Richards

et al. 2012

ApJ

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This paper presents both the result of a search for fossil systems (FSs) within the XMM Cluster Survey and the Sloan Digital Sky Survey and the results of a study of the stellar mass assembly and stellar populations of their fossil galaxies. In total, 17 groups and clusters are identified at z < 0.25 with large magnitude gaps between the first and fourth brightest galaxies. All the information necessary to classify these systems as fossils is provided. For both groups and clusters, the total and fractional luminosity of the brightest galaxy is positively correlated with the magnitude gap. The brightest galaxies in FSs (called fossil galaxies) have stellar populations and star formation histories which are similar to normal brightest cluster galaxies (BCGs). However, at fixed group/cluster mass, the stellar masses of the fossil galaxies are larger compared to normal BCGs, a fact that holds true over a wide range of group/cluster masses. Moreover, the fossil galaxies are found to contain a significant fraction of the total optical luminosity of the group/cluster within 0.5R 200 , as much as 85%, compared to the non-fossils, which can have as little as 10%. Our results suggest that FSs formed early and in the highest density regions of the universe and that fossil galaxies represent the end products of galaxy mergers in groups and clusters. The online FS catalog can be found at

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Section: Discussionmentioning

confidence: 98%

THEXMMCLUSTER SURVEY: THE STELLAR MASS ASSEMBLY OF FOSSIL GALAXIES

Harrison

Miller

Richards

et al. 2012

ApJ

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“…However, the LF slope is similar to that of clusters with σ < 800 km s −1 and BM type < II. This would suggest that these starforming dwarf galaxies are preferentially preserved in low mass environments or are destroyed in higher density systems, with many large giants, rather than a single dominant system -it is possible that most of the growth of brightest cluster galaxies may take place outside of clusters -an intriguing parallel may be offered by the 'infalling' cD galaxy in the Coma NGC4839 subgroup or the J0454-0309 fossil subgroup (Schirmer et al 2010).…”

Section: Environmental Effectsmentioning

confidence: 99%

TheK-band luminosity functions of cluster galaxies

Propris¹

2016

Mon. Not. R. Astron. Soc.

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We derive the galaxy luminosity function in the K s band for galaxies in 24 clusters to provide a local reference for higher redshift studies and to analyse how and if the luminosity function varies according to environment and cluster properties. We use new, deep K band imaging and match the photometry to available redshift information and to optical photometry from the SDSS or the UKST/POSS: > 80% of the galaxies to K ∼ 14.5 have measured redshifts. We derive composite luminosity functions, for the entire sample and for cluster subsamples . We consider the luminosity functions for red sequence and blue cloud galaxies. The full composite luminosity function has K * = 12.79 ± 0.14 (M K = −24.81) and α = −1.41 ± 0.10. We find that K * is largely unaffected by the environment but that the slope α increases towards lower mass clusters and clusters with Bautz-Morgan type < II. The red sequence luminosity function seems to be approximately universal (within errors) in all environments: it has parameters K * = 13.16 ± 0.15 (M K = −24.44) and α = −1.00 ± 0.12 (for all galaxies). Blue galaxies do not show a good fit to a Schechter function, but the best values for its parameters are K * = 13.51 ± 0.41 (M K = −24.09) and α = −1.60 ± 0.29: we do not have enough statistics to consider environmental variations for these galaxies. We find some evidence that K * in clusters is brighter than in the field and α is steeper, but note this comparison is based (for the field) on 2MASS photometry, while our data are considerably deeper.

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“…Since then, several other objects have been assigned to this class in the last few years (Vikhlinin et al 1999;Jones et al 2003;Yoshioka et al 2004;Sun et al 2004;Khosroshahi et al 2004;Ulmer et al 2005;Schirmer et al 2010;Pierini et al 2011;Miller et al 2012). Jones et al (2003) estimated fossils to be Reduced spectra are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/553/A99 quite frequent, constituting 8−20% of all systems with comparable X-ray luminosity (≥10 42 erg s −1 ).…”

Section: Introductionmentioning

confidence: 99%

Age and metallicity gradients in fossil ellipticals

Eigenthaler¹,

Zeilinger²

2013

A&A

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Context. Fossil galaxy groups are speculated to be old and highly evolved systems of galaxies that formed early in the universe and had enough time to deplete their L * galaxies through successive mergers of member galaxies, building up one massive central elliptical, but retaining the group X-ray halo. Aims. Considering that fossils are the remnants of mergers in ordinary groups, the merger history of the progenitor group is expected to be imprinted in the fossil central galaxy (FCG). We present for the first time radial gradients of single-stellar population (SSP) ages and metallicites in a sample of FCGs to constrain their formation scenario. We also measure line-strength gradients for the strongest absorption features in these galaxies. Methods. We took deep spectra with the long-slit spectrograph ISIS at the William Herschel Telescope (WHT) for six FCGs. The obtained spectra are fit with Pegase HR SSP models within the full-spectrum fitting package ULySS yielding SSP ages and metallicities of the stellar populations. We measure radial gradients of SSP ages and metallicities along the major axes. Lick indices are measured for the strongest absorption features to determine line-strength gradients and compare with the full-spectrum fitting results. Results. Our sample comprises some of the most massive galaxies in the universe exhibiting an average central velocity dispersion of σ 0 = 271 ± 28 km s −1 . Metallicity gradients are throughout negative with comparatively flat slopes of ∇ [Fe/H] = −0.19 ± 0.08 while age gradients are found to be insignificant (∇ age = 0.00 ± 0.05). All FCGs lie on the fundamental plane, suggesting that they are virialised systems. We find that gradient strengths and central metallicities are similar to those found in cluster ellipticals of similar mass. Conclusions. The comparatively flat metallicity gradients with respect to those predicted by monolithic collapse (∇ Z = −0.5) suggest that fossils are indeed the result of multiple major mergers. Hence we conclude that fossils are not "failed groups" that formed with a top-heavy luminosity function. The low scatter of gradient slopes suggests a similar merging history for all galaxies in our sample.

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J0454-0309: evidence of a strong lensing fossil group falling into a poor galaxy cluster

Cited by 21 publications

References 94 publications

THEXMMCLUSTER SURVEY: THE STELLAR MASS ASSEMBLY OF FOSSIL GALAXIES

THEXMMCLUSTER SURVEY: THE STELLAR MASS ASSEMBLY OF FOSSIL GALAXIES

TheK-band luminosity functions of cluster galaxies

Age and metallicity gradients in fossil ellipticals

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