J/AJ/148/117ivo://CDS.VizieR/J/AJ/148/117doi:10.26093/cds/vizier.51480117CDSJorgensen I.Chiboucas K.Toft S.Bergmann M.Zirm A.Schiavon R.P.,Grutzbauch R.2017-07-10T08:51:00Z2017-01-09T08:10:00ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frgalaxy-clustersgalaxiesspectroscopyhst-photometrygalaxy-kinematicsredshiftedRX J0848.6+4453 (Lynx W) at redshift 1.27 is part of the Lynx Supercluster of galaxies. We present an analysis of the stellar populations and star formation history for a sample of 24 members of the cluster. Our study is based on deep optical spectroscopy obtained with Gemini North combined with imaging data from Hubble Space Telescope. Focusing on the 13 bulge-dominated galaxies for which we can determine central velocity dispersions, we find that these show a smaller evolution with redshift of sizes and velocity dispersions than reported for field galaxies and galaxies in poorer clusters. Our data show that the galaxies in RX J0848.6+4453 populate the fundamental plane (FP) similar to that found for lower-redshift clusters. The zero-point offset for the FP is smaller than expected if the cluster's galaxies are to evolve passively through the location of the FP we established in our previous work for z=0.8-0.9 cluster galaxies and then to the present-day FP. The FP zero point for RXJ0848.6+4453 corresponds to an epoch of last star formation at z_form_=1.95_-0.15_^+0.22^. Further, we find that the spectra of the galaxies in RXJ0848.6+4453 are dominated by young stellar populations at all galaxy masses and in many cases show emission indicating low-level ongoing star formation. The average age of the young stellar populations as estimated from the strength of the high-order Balmer line H{zeta} is consistent with a major star formation episode 1-2Gyr prior, which in turn agrees with z_form_=1.95. These galaxies dominated by young stellar populations are distributed throughout the cluster. We speculate that low-level star formation has not yet been fully quenched in the center of this cluster, possibly because the cluster is significantly poorer than other clusters previously studied at similar redshifts, which appear to have very little ongoing star formation in their centers. The mixture in RXJ0848.6+4453 of passive galaxies with young stellar populations and massive galaxies still experiencing some star formation appears similar to the galaxy populations recently identified in two z{approx}2 clusters.2014AJ....148..117Jhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/148/117CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/252 : The USNO-A2.0 Catalogue (Monet+ 1998)J/AJ/145/77 : Im. and spectroscopy in 3 galaxy clusters (Jorgensen+, 2013)J/ApJS/184/271 : Photometry of galaxies in 3 clusters (Chiboucas+, 2009)J/A+AS/139/29 : Empirical calibration of the 4000 A break (Gorgas+, 1999)J/MNRAS/276/1341 : Spectroscopy of E and S0 galaxies (Jorgensen+, 1995)J/MNRAS/273/1097 : CCD photometry for E and S0 galaxies (Jorgensen+ 1995)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/148/117https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/148/117http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/148/117https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/148/117https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/148/117http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/148/117GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/148/117/RXJ0848 ()https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/148/117/RXJ0848?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/148/117/RXJ0848?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/148/117/RXJ0848?GETtext/xml+votable180.050000true132.200833344.86913890.0055555555555555566/6495 71782.1350832807657816e-19 2.2630631615001444e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/148/117?format=asciiOpticaldefaultJ/AJ/148/117/table12RX J0848.6+4453: line indices and [OII] for cluster membersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGalaxy[240/3090] Galaxy identifiermeta.id;meta.mainintCN3883[0.07/0.202]? The CN3883 absorption-line index; in {AA} (1)0.1nmspect.indexfloatnullablee_CN3883[0.005/0.03]? Uncertainty in CN3883 ({sigma}_CN3883_); in {AA}0.1nmstat.errorfloatnullableCaHK[11.4/27.7]? The CaHK absorption-line index; in {AA} (1)0.1nmspect.indexfloatnullablee_CaHK[0.27/1.63]? Uncertainty in CaHK ({sigma}_CaHK_); in {AA}0.1nmstat.errorfloatnullableD4000[1.544/3.154]? The D4000 absorption-line index (measured as D4000_short_; cf. Eq. (B2) in the text); in {AA} (1)0.1nmspect.indexfloatnullablee_D4000[0.006/0.042]? Uncertainty in D4000 ({sigma}_D4000_); in {AA}0.1nmstat.errorfloatnullableHzA[1.99/12.68]? The H{zeta}_A_ Balmer absorption-line index; in {AA} (1)0.1nmspect.indexfloatnullablee_HzA[0.14/0.62]? Uncertainty in HzA ({sigma}_H{zeta}A_); in {AA}0.1nmstat.errorfloatnullableEWOII[1.9/183.5]? [OII] equivalent width; in {AA}0.1nmspect.line.eqWidthfloatnullablee_EWOII[0.3/123.5]? Uncertainty in EWOII ({sigma}_EW[OII]_); in {AA}0.1nmstat.errorfloatnullableF[OII][0.57/10.29]? Relative [OII] flux measured within the spectral aperture (in units of 10^-15^erg/cm^2^/s/{AA})1e-17W.m**-2.nm**-1phot.flux;arith.ratiofloatnullablee_F[OII][0.11/0.4]? Uncertainty in Flux {sigma}_flux([OII]_)1e-17W.m**-2.nm**-1stat.errorfloatnullableJ/AJ/148/117/RXJ0848recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGalaxy[240/9001] Galaxy identifiermeta.id;meta.mainintprimaryRAJ2000Hour of Right Ascension (J2000) (1)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000) (1)pos.eq.dec;meta.mainz.SEx[21.2/24.89] Total HST/ACS F850LP magnitude from SExtractor (m_tot_,SEx) (2)magphot.mag;em.opt.Ifloati-z[0.018/1.075] Aperture HST/ACS F775W-F850LP color index within an aperture with radius 0.5'' (i_775_-z_850_) (2)magphot.color;em.opt.I;em.opt.Ifloatz.dev[20.76/24.86]? Total HST/ACS F850LP magnitude from fit with r^1/4^ profile (m_tot_,dev) (2)magphot.mag;em.opt.Ifloatnullabler.dev[-1.125/0.392]? Logarithm of the effective radius in arcsec from fit with r^1/4^ profile (log r_e_,dev) (3)log(arcsec)phys.angSizefloatnullablez.ser[21.05/24.88]? Total HST/ACS F850LP magnitude from a fit with a Sersic profile (m_tot_,ser) (2)magphot.mag;em.opt.Ifloatnullabler.ser[-1.11/0.324]? Logarithm of the effective radius from a fit with a Sersic profile (log r_e_,ser) (3)log(arcsec)phys.angSizefloatnullablel_n[>] Lower limit flag on nmeta.code.errorcharn[0.3/9.1] Sersic index (n_ser_) (4)stat.fit.paramfloatf_n[a] Flag 'a' means that no reliable Sersic fit can be derived owing to scattered light from a nearby sourcemeta.codecharPA[-90/90] Position angle of major axis measured from north through eastdegpos.posAngfloatEll[0.05/0.84] Ellipticity {epsilon}src.ellipticityfloatz[0.43/1.33]? Spectroscopic redshiftsrc.redshiftfloatnullableMm[0/2] Adopted membership (1=galaxy is a member of the cluster, 0=galaxy is not a member, or 2=no redshift) (5)meta.code.memberintsigma1[1.975/2.631]? Log of velocity dispersion (log{sigma})log(km.s**-1)phys.veloc.dispersionfloatnullablee_sigma1[0.04/0.21]? Uncertainty on the velocity dispersion ({sigma}_log{sigma}_) (6)log(km.s**-1)stat.errorfloatnullablesigma2[2/2.651]? Log of corrected velocity dispersion (log{sigma}_cor_) (7)log(km.s**-1)phys.veloc.dispersionfloatnullableB8V[0/1]? Fraction of the template star of spectral type B8V in the spectra (8)statfloatnullableG1V[0/1]? Fraction of the template star of spectral type G1V in the spectra (8)statfloatnullableK0III[0/1]? Fraction of the template star of spectral type K0III in the spectra (8)statfloatnullablechi2[0.8/7.8]? {Chi}^2^stat.fit.chi2floatnullableS/N[2.6/61.8] Signal-to-noise ratio per {AA} in the rest frame of the galaxy (9)stat.snr;src.class.starGalaxyfloatSimbadSimbad column added by the CDSmeta.ref.urlchar