The dark matter halo structure of “fossil” groups candidates

Yoshioka, T.; Furuzawa, Akihiro; Takahashi, Shinji; Tawara, Yuzuru; Sato, Shuji; Yamashita, Koujun; Kumai, Y.

doi:10.1016/j.asr.2003.03.076

Cited by 32 publications

(60 citation statements)

References 14 publications

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“…For example, Yoshioka et al (2004) observe mass-tolight ratios as high as 1000, which are difficult to explain if these galaxies assembled their mass only through dynamical friction. Another uncertainty lies in the type of the galaxies from which the giant elliptical forms.…”

Section: Fossil Groupsmentioning

confidence: 99%

“…This can lead to isolated giant elliptical galaxies, embedded in X-ray haloes with luminosities characteristic for entire galaxy groups. Such objects exist in the Universe (Vikhlinin et al 1999), either isolated (Yoshioka et al 2004) or surrounded by groups of less luminous satellite galaxies (Jones et al 2003;Khosroshahi et al 2006b; La Barbera et al 2009). One of the first systems has been reported by Ponman et al (1994) coining the term "fossil group", and Jones et al (2003) have introduced general selection criteria.…”

Section: Fossil Groupsmentioning

confidence: 99%

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

Schirmer¹,

Suyu²,

Schrabback

et al. 2010

A&A

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Aims. We have discovered a strong lensing fossil group (J0454) projected near the well-studied cluster MS0451-0305. Using the large amount of available archival data, we compare J0454 to normal groups and clusters. A highly asymmetric image configuration of the strong lens enables us to study the substructure of the system. Methods. We used multicolour Subaru/Suprime-Cam and CFHT/Megaprime imaging, together with Keck spectroscopy to identify member galaxies. A VLT/FORS2 spectrum was taken to determine the redshifts of the brightest elliptical and the lensed arc. Using HST/ACS images, we determined the group's weak lensing signal and modelled the strong lens system. This is the first time that a fossil group is analysed with lensing methods. The X-ray luminosity and temperature were derived from XMM-Newton data. Results. J0454 is located at z = 0.26, with a gap of 2.5 mag between the brightest and second brightest galaxies within half the virial radius. Outside a radius of 1.5 Mpc, we find two filaments extending over 4 Mpc, and within we identify 31 members spectroscopically and 33 via the red sequence with i < 22 mag. (BGG) is inconsistent with the dynamic centre of J0454. It strongly lenses a galaxy at z = 2.1 ± 0.3, and we model the lens with a pseudo-isothermal elliptical mass distribution. A high external shear, and a discrepancy between the Einstein radius and the weak lensing velocity dispersion requires that the BGG must be offset from J0454's dark halo centre by at least 90−130 kpc. The X-ray halo is offset by 24 ± 16 kpc from the BGG, shows no signs of a cooling flow and can be fit by a single β-model. With L X = (1.4 ± 0.2) × 10 43 erg s −1 J0454 falls onto standard cluster scaling relations, but appears cooler (T = 1.1 ± 0.1 keV) than expected (T ∼ 2.0 keV). Taken all together, these data indicate that J0454 consists of two systems, a sparse cluster and an infalling fossil group, where the latter seeds the brightest cluster galaxy. An alternative to the sparse cluster could be a filament projected along the line of sight mimicking a cluster, with galaxies streaming towards the fossil group.

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Section: Fossil Groupsmentioning

confidence: 99%

Section: Fossil Groupsmentioning

confidence: 99%

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

Schirmer¹,

Suyu²,

Schrabback

et al. 2010

A&A

View full text Add to dashboard Cite

show abstract

“…They also noted a central point source, possibly an AGN. Yoshioka et al (2004) analyzed ASCA data for NGC 1132 and classified it as an "isolated X-ray overluminous elliptical galaxy" (IOLEG). For ESO 306-017, we use the results from Sun et al (2004), who analyzed Chandra and XMM-Newton data and averaged the results of these analyses.…”

Section: Comparisons With X-ray Datamentioning

confidence: 99%

“…At present, there is no consensus on the mass-to-light ratios (M/L) of FGs; measurements span from ∼100 M /L (Khosroshahi et al 2004) to ∼1000 M /L (Vikhlinin et al 1999;Yoshioka et al 2004;Cypriano et al 2006) in the R-band, but there is a tendency toward higher values Eigenthaler & Zeilinger 2012). Such high M/L values, together with the fact that FGs show unusually high L X /L opt ratios compared with typical galaxy groups, appear inconsistent with the assumption that FGs are formed by the merging of the members in ordinary galaxy groups (see Fig.…”

Section: Introductionmentioning

confidence: 99%

Globular cluster systems in fossil groups: NGC 6482, NGC 1132, and ESO 306-017

Álamo-Martínez

West

Blakeslee

et al. 2012

A&A

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We study the globular cluster (GC) systems in three representative fossil group galaxies: the nearest (NGC 6482), the prototype (NGC 1132) and the most massive known to date . This is the first systematic study of GC systems in fossil groups. Using data obtained with the Hubble Space Telescope Advanced Camera for Surveys in the F475W and F850LP filters, we determine the GC color and magnitude distributions, surface number density profiles, and specific frequencies. In all three systems, the GC color distribution is bimodal, the GCs are spatially more extended than the starlight, and the red population is more concentrated than the blue. The specific frequencies seem to scale with the optical luminosities of the central galaxy and span a range similar to that of the normal bright elliptical galaxies in rich environments. We also analyze the galaxy surface brightness distributions to look for deviations from the best-fit Sérsic profiles; we find evidence of recent dynamical interaction in all three fossil group galaxies. Using X-ray data from the literature, we find that luminosity and metallicity appear to correlate with the number of GCs and their mean color, respectively. Interestingly, although NGC 6482 has the lowest mass and luminosity in our sample, its GC system has the reddest mean color, and the surrounding X-ray gas has the highest metallicity.

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“…All this together and the absent of L galaxies suggest that they arguably are old galaxy groups. Up to now more than one hundred galaxy groups have been classified as "fossil groups" by different studies (Ponman et al 1994;Jones et al 2003;Yoshioka et al 2004;Khosroshahi, Jones & Ponman 2004;Vikhlinin et al 1999;Voevodkin et al 2010;Santos, Mendes de Oliveira & Sodr 2007;Schirmer et al 2010;La Barbera et al 2009;Lopes de Oliveira et al 2010;Proctor et al 2011;Pierini et al 2011;Miller et al 2012;Eigenthaler & Zeilinger 2009). However, the selection criteria are not strictly met in all studies and vary from the convention introduced by Jones et al (2003).…”

Section: Introductionmentioning

confidence: 99%

IGM heating in fossil galaxy groups

Miraghaei

Khosroshahi

Klöckner

et al. 2014

Monthly Notices of the Royal Astronomical Society

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We study intergalactic medium (IGM) heating in a sample of five fossil galaxy groups by using their radio properties at 610 MHz and 1.4 GHz. The power by radio jets introducing mechanical heating for the sampled objects is not sufficient enough to suppress the cooling flow. Therefore, we discussed shock-, vortex heating, and conduction as alternative heating processes. Further, the 1.4 GHz and 610 MHz radio luminosities of fossil groups are compared to a sample of normal galaxy groups of the same radio brightest (BGGs), stellar mass, and total group stellar mass, quantified using the K-band luminosity. It appears that the fossil BGGs are under luminous at 1.4 GHz and 610 MHz for a given BGG stellar mass and luminosity, in comparison to a general population of the groups. In addition, we explore how the bolometric radio luminosity of fossil sample depends on clusters and groups characteristics. Using the HIghest X-ray FLUx Galaxy Cluster Sample (HIFLUGCS) as a control sample we found that the large-scale behaviours of fossil galaxy groups are consistent with their relaxed and virialised nature.

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The dark matter halo structure of “fossil” groups candidates

Cited by 32 publications

References 14 publications

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

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

Globular cluster systems in fossil groups: NGC 6482, NGC 1132, and ESO 306-017

IGM heating in fossil galaxy groups

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