J/ApJ/805/99ivo://CDS.VizieR/J/ApJ/805/99doi:10.26093/cds/vizier.18050099CDSMulia A.J.Chandar R.Whitmore B.C.2018-01-05T08:56:41Z2015-10-19T13:47:46ZCDS support team

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

cds-question@unistra.frglobular-star-clustersgalaxieshst-photometryWe study the stellar content in the tidal tails of three nearby merging galaxies, NGC 520, NGC 2623, and NGC 3256, using BVI imaging taken with the Advanced Camera for Surveys on board the Hubble Space Telescope (HST). The tidal tails in all three systems contain compact and fairly massive young star clusters, embedded in a sea of diffuse, unresolved stellar light. We compare the measured colors and luminosities with predictions from population synthesis models to estimate cluster ages and find that clusters began forming in tidal tails during or shortly after the formation of the tails themselves. We find a lack of very young clusters (<=10Myr old), implying that eventually star formation shuts off in the tails as the gas is used up or dispersed. There are a few clusters in each tail with estimated ages that are older than the modeled tails themselves, suggesting that these may have been stripped out from the original galaxy disks. The luminosity function of the tail clusters can be described by a single power-law, dN/dL{propto}L^{alpha}^, with -2.6<{alpha}<-2.0. We find a stellar age gradient across some of the tidal tails, which we interpret as a superposition of (1) newly formed stars and clusters along the dense center of the tail and (2) a sea of broadly distributed, older stellar material ejected from the progenitor galaxies.2015ApJ...805...99Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/805/99CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/hst : HST Archived Exposures Catalog (STScI, 2007)J/MNRAS/405/857 : Star clusters in NGC 3256 (Goddard+, 2010)J/A+A/435/65 : UBVI phot. of NGC 6872 clusters population (Bastian+, 2005)J/A+AS/139/393 : Young Massive Star Clusters. II. (Larsen, 1999)J/AJ/118/752 : BI phot. of NGC 3256 young globular clusters (Zepf+, 1999)J/AJ/109/960 : Young star clusters in The Antennae (Whitmore+ 1995)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/805/99https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/805/99http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/805/99https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/805/99https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/805/99http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/805/99GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/805/99/table3 (Properties of star clusters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/805/99/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/805/99/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/805/99/table3?GETtext/xml+votable180.050000true21.14612923.79241110.005555555555555556Cone search capability for table J/ApJ/805/99/table4 (Cluster catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/805/99/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/805/99/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/805/99/table4?GETtext/xml+votable180.050000true21.1323753.79973060.0055555555555555566/4993 18212 38139https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/805/99?format=asciiOpticaldefaultJ/ApJ/805/99/table3Properties of star clustersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNGCGalaxy NGC numbermeta.id;meta.mainintm_NGC[NSEP] Tidal tail identifiermeta.code.multipcharn_NGCTidal tail detailed namemeta.notecharl_tauT[<= ] Limit flag on taumeta.code.errortauT[220/450] Predicted age of the tidal tail as estimated from simulations ({tau}_tail_)Myrtime.ageintNcl[5/141] Total number of clusters found in the regionmeta.numberintCl[0/8.5] star cluster density per kpc^2^ where M_V_<-8.5 ({Sigma}_clus_)kpc**-2phys.densityfloatl_tauC[>=~ ] Limit flag on tauCmeta.code.errortauC[100/260]? Approximate age of the bulk cluster formation ({tau}_clus_)Myrphys.SFRintnullable<B-V>[0.05/0.3] B-V color index (1)magphot.color;em.opt.B;em.opt.Vfloate_<B-V>[0.05/0.2] <B-V> uncertaintymagstat.error;phot.color;em.opt.Bfloat<V-I>[0.3/0.6] V-I color index (1)magphot.color;em.opt.V;em.opt.Ifloate_<V-I>[0.05/0.3] <V-I> uncertaintymagstat.error;phot.color;em.opt.Vfloatalpha[-2.7/-2]? Luminosity function {alpha} value (2)phys.luminosity.funfloatnullablee_alpha[0.2/0.4]? alpha uncertaintystat.error;pos.eq.rafloatnullableSimbadSimbad column added by the CDSmeta.ref.urlcharNEDSimbad column added by the CDSmeta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/ApJ/805/99/table4Cluster catalogNGCGalaxy NGC numbermeta.id.parentintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintm_NGC[NSEP] Tidal tail identifiermeta.code.multipcharSeq[1/141] Cluster identifier in galaxy tidal tailmeta.id;meta.mainintRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degrees of Declination (J2000)pos.eq.dec;meta.mainBmag[21.5/27.2] Apparent HST/ACS B band magnitudemagphot.mag;em.opt.Bfloate_Bmag[0/0.4] Error in Bmagmagstat.error;phot.mag;em.opt.BfloatVmag[21.4/26.4] Apparent HST/ACS V band magnitudemagphot.mag;em.opt.Vfloate_Vmag[0.01/0.3] Error in Vmagmagstat.error;phot.mag;em.opt.VfloatImag[20.9/26.6] Apparent HST/ACS I band magnitudemagphot.mag;em.opt.Ifloate_Imag[0/0.6] Error in Imagmagstat.error;phot.mag;em.opt.IfloatlogAge[5.1/10.3] Cluster agelog(yr)time.agefloat