Ages of S0 and Elliptical Galaxies in the Coma Cluster

Poggianti, Bianca M.; Bridges, Terry J.; Carter, Dave; Mobasher, Bahram; Doi, Mamoru; Iye, Masanori; Kashikawa, Nobunari; Komiyama, Yutaka; Okamura, S.; Sekiguchi, M.; Shimasaku, Kazuhiro; Yagi, Masafumi; Yasuda, Naoki

doi:10.1086/323767

Cited by 103 publications

(141 citation statements)

References 59 publications

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“…1, the different properties found for S0s in different environments probably indicate different formation mechanisms. Spirals in clusters seem to have turned into S0s through environmental-related processes during the last ∼7-8 Gyr (Poggianti et al 2001(Poggianti et al , 2009, whereas this transformation seems to have been led by mergers and tidal interactions in groups during the same period (Wilman et al 2009;Bekki & Couch 2011). Considering that ∼50% of S0s reside in groups or in groups that are falling into a cluster (Huchra & Geller 1982;Berlind et al 2006;Crook et al 2007;Wilman et al 2009), the percentage of S0s that may have experienced major encounters is therefore similar to the percentage of S0s located onto the linear correlation in the δ -e diagram estimated above.…”

Section: Discussionmentioning

confidence: 99%

Evolution induced by dry minor mergers onto fast-rotator S0 galaxies

Tapia

Eliche‐Moral

Balcells

et al. 2014

A&A

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Context. Numerical studies have shown that the properties of the S0 galaxies with kinematics intermediate between fast and slow rotators are difficult to explain by a scenario of major mergers. Aims. We investigate whether the smoother perturbation induced by minor mergers can reproduce these systems. Methods. We analysed collisionless N-body simulations of intermediate and minor dry mergers onto S0s to determine the structural and kinematic evolution induced by the encounters. The original primary galaxies represent gas-poor fast-rotator S0b and S0c galaxies with high intrinsic ellipticities. The original bulges are intrinsically spherical and have low rotation. Different mass ratios, parent bulges, density ratios, and orbits were studied. Results. Minor mergers induce a lower decrease of the global rotational support (as provided by λ e ) than encounters of lower mass ratios, which results in S0s with properties intermediate between fast and slow rotators. The resulting remnants are intrinsically more triaxial, less flattened, and span the whole range of apparent ellipticities up to e ∼ 0.8. They do not show lower apparent ellipticities in random projections than initially; on the contrary, the formation of oval distortions and the disc thickening increase the percentage of projections at 0.4 < e < 0.7. In the experiments with S0b progenitor galaxies, minor mergers tend to spin up the bulge and to slightly decrease its intrinsic ellipticity, whereas in the cases of primary S0c galaxies they keep the rotational support of the bulge nearly constant and significantly decrease its intrinsic ellipticity. The remnant bulges remain nearly spherical (B/A ∼ C/A > 0.9), but exhibit a wide range of triaxialities (0.20 < T < 1.00). In the plane of global anisotropy of velocities (δ) vs. intrinsic ellipticity ( e,intr ), some of our models extend the linear trend found in previous major merger simulations towards higher e,intr values, while others clearly depart from it (depending on the progenitor S0). This is consistent with the wide dispersion exhibited by real S0s in this diagram compared with ellipticals, which follow the linear trend drawn by major merger simulations. Conclusions. The smoother changes induced by minor mergers can explain the existence of S0s with intermediate kinematic properties between fast and slow rotators that are difficult to explain with major mergers. The different trends exhibited by ellipticals and S0 galaxies in the δ -e diagram may be pointing to the different role played by major mergers in the build-up of each morphological type.

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Section: Discussionmentioning

confidence: 99%

Evolution induced by dry minor mergers onto fast-rotator S0 galaxies

Tapia

Eliche‐Moral

Balcells

et al. 2014

A&A

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“…Direct observational evidence of a rapid quenching of the star formation activity of cluster galaxies are poststarburst objects in the periphery of nearby clusters such as Coma and A1367 (Poggianti et al 2001a(Poggianti et al ,b, 2004Smith et al 2008Smith et al , 2009Smith et al , 2012Gavazzi et al 2010). These objects are frequent also in other nearby Vulcani et al 2015) Fig.…”

Section: Comparison With Previous Studiesmentioning

confidence: 99%

Quenching of the star formation activity in cluster galaxies

Boselli

Roehlly

Fossati

et al. 2016

A&A

119

155

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We study the star formation quenching mechanism in cluster galaxies by fitting the spectral energy distribution (SED) of the Herschel Reference Survey, a complete volume-limited K-band-selected sample of nearby galaxies including objects in different density regions, from the core of the Virgo cluster to the general field. The SEDs of the target galaxies were fitted using the CIGALE SED modelling code. The truncated activity of cluster galaxies was parametrised using a specific star formation history with two free parameters, the quenching age QA and the quenching factor QF. These two parameters are crucial for the identification of the quenching mechanism, which acts on long timescales when starvation processes are at work, but is rapid and efficient when ram pressure occurs. To be sensitive to an abrupt and recent variation of the star formation activity, we combined twenty photometric bands in the UV to far-infrared in a new way with three age-sensitive Balmer line absorption indices extracted from available medium-resolution (R ∼ 1000) integrated spectroscopy and with Hα narrow-band imaging data. The use of a truncated star formation history significantly increases the quality of the fit in HI-deficient galaxies of the sample, that is to say, in those objects whose atomic gas content has been removed during the interaction with the hostile cluster environment. The typical quenching age of the perturbed late-type galaxies is QA < ∼ 300 Myr whenever the activity of star formation is reduced by 50% < QF ≤ 80% and QA < ∼ 500 Myr for QF > 80%, while that of the quiescent early-type objects is QA 1−3 Gyr. The fraction of late-type galaxies with a star formation activity reduced by QF > 80% and with an HI-deficiency parameter HI − de f > 0.4 drops by a factor of ∼5 from the inner half virial radius of the Virgo cluster (R/R vir < 0.5), where the hot diffuse X-ray emitting gas of the cluster is located, to the outer regions (R/R vir > 4). The efficient quenching of the star formation activity observed in Virgo suggests that the dominant stripping process is ram pressure. We discuss the implication of this result in the cosmological context of galaxy evolution.

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“…However, the giant elliptical galaxies in these z ¼ 0:83 clusters are clearly already in place: the evidence suggests that bright cluster elliptical galaxies mainly undergo passive evolution at z P 1 (Holden et al 2005a(Holden et al , 2005b and that most of the morphological evolution occurs in the transformation of field spiral and irregular galaxies into cluster S0 and dwarf galaxies (e.g., Larson et al 1980;Dressler et al 1997;Postman et al 2005). The resolution lies in correctly identifying the descendants of the distant cluster elliptical galaxies; the data for the brightest elliptical galaxies in nearby massive clusters actually indicate ages of $10 Gyr or more (e.g., Poggianti et al 2001;Vazdekis et al 2001), in line with the ages we measure for their likely progenitors at z > 0:8. The lingering star formation seen in these clusters (e.g., Homeier et al 2005) is likely only of minor importance in terms of mass, a point that we will take up in a forthcoming paper (B.…”

Section: Transformation To Rest-frame Colorsmentioning

confidence: 99%

Clusters at Half Hubble Time: Galaxy Structure and Colors in RX J0152.7−1357 and MS 1054−03

Blakeslee

Holden

Franx

et al. 2006

ApJ

122

164

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We study the photometric and structural properties of spectroscopically confirmed members in the two massive X-ray-selected z % 0:83 galaxy clusters MS 1054-03 and RX J0152.7À1357 using three-band mosaic imaging with the Hubble Space Telescope Advanced Camera for Surveys. The samples include 105 and 140 members of RX J0152.7À1357 and MS 1054-03, respectively, to i 775 < 24:0. A quantitative classification scheme using Sérsic indices and ''bumpiness'' (the ratio of the rms residuals to the model mean) was found to correlate well with visual morphological type. The color-magnitude residuals correlate well with the local density, as measured from both galaxy numbers and weak lensing. Weaker correlations are found with cluster radius (the fundamental dependence is on local density). We identify a threshold surface mass density of AE % 0:1, in units of the critical density, above which there are relatively few blue (star-forming) galaxies. In RX J0152.7À1357, there is an offset of 0:006 AE 0:002 in the mean redshifts of the early-and late-type galaxies, possibly from an infalling foreground association of late-type galaxies. A range of star-formation time-scales are needed to reproduce the galaxy loci in the color-color diagrams. We find rest-frame scatters for the ellipticals of 0:03 AE 0:01 mag in U À B and 0:07 AE 0:01 mag in U À V . The mean colors and their scatters imply ages $3.5 Gyr, or formation at z % 2:2. Thus, when the universe was half its present age, cluster ellipticals were about half the age of the universe; the same is coincidentally true of the median ages of ellipticals today. However, the most massive local ellipticals have ages k10 Gyr, consistent with our results for their likely progenitors at z k 0:8.

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Ages of S0 and Elliptical Galaxies in the Coma Cluster

Cited by 103 publications

References 59 publications

Evolution induced by dry minor mergers onto fast-rotator S0 galaxies

Evolution induced by dry minor mergers onto fast-rotator S0 galaxies

Quenching of the star formation activity in cluster galaxies

Clusters at Half Hubble Time: Galaxy Structure and Colors in RX J0152.7−1357 and MS 1054−03

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