J/MNRAS/504/3580ivo://CDS.VizieR/J/MNRAS/504/3580doi:10.26093/cds/vizier.75043580CDSSaifollahi T.Janz J.Peletier R.F.Cantiello M.Hilker M.Mieske S.,Valentijn E.A.Venhola A.Kleijn G.V.2024-08-21T20:17:42Z2021-12-31T10:22:01ZCDS support team

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

cds-question@unistra.frgalaxy-clustersinfrared-photometryUltra-compact dwarf galaxies (UCDs) were serendipitously discovered by spectroscopic surveys in the Fornax cluster 20 yr ago. Nowadays, it is commonly accepted that many bright UCDs are the nuclei of galaxies that have been stripped. However, this conclusion might be driven by biased samples of UCDs in high-density environments, on which most searches are based. With the deep optical images of the Fornax Deep Survey, combined with public near-infrared data, we revisit the UCD population of the Fornax cluster and search for UCD candidates, for the first time, systematically out to the virial radius of the galaxy cluster. Our search is complete down to magnitude m_g_=21mag or M_g_~-10.5mag at the distance of the Fornax cluster. The UCD candidates are identified and separated from foreground stars and background galaxies by their optical and near-infrared colours. This primarily utilizes the u-i/i-Ks diagram and a machine learning technique is employed to incorporate other colour combinations to reduce the number of contaminants. The newly identified candidates (44) in addition to the spectroscopically confirmed UCDs (61), increase the number of known Fornax UCD considerably (105). Almost all of the new UCD candidates are located outside the Fornax cluster core (360kpc), where all of the known UCDs were found. The distribution of UCDs within the Fornax cluster shows that a population of UCDs may form in low-density environments. This most likely challenges the current models of UCD formation.2021MNRAS.504.3580Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/504/3580CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/504/3580https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/504/3580http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/504/3580https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/504/3580https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/504/3580http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/504/3580GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/504/3580/tablea1 (Catalogue of the spectroscopically confirmed ultra-compact dwarf galaxies (UCD) and globular clusters (GCs) in the Fornax cluster)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/504/3580/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/504/3580/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/504/3580/tablea1?GETtext/xml+votable180.050000true54.72505306-35.559170.005555555555555556Cone search capability for table J/MNRAS/504/3580/tablea2 (Catalogue of the spectroscopic foreground stars (galaxies farthur than the Fornax Galaxy Cluster))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/504/3580/tablea2?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/504/3580/tablea2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/504/3580/tablea2?GETtext/xml+votable180.050000true52.91059694-35.887081110.005555555555555556Cone search capability for table J/MNRAS/504/3580/tablea3 (Catalogue of the spectroscopic background galaxies (Milky Way stars))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/504/3580/tablea3?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/504/3580/tablea3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/504/3580/tablea3?GETtext/xml+votable180.050000true54.69535889-35.788171110.005555555555555556Cone search capability for table J/MNRAS/504/3580/tablea4 (*The UNKNOWN catalogue)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/504/3580/tablea4?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/504/3580/tablea4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/504/3580/tablea4?GETtext/xml+votable180.050000true52.96336194-37.049098890.005555555555555556Cone search capability for table J/MNRAS/504/3580/tablea5 (Catalogue of the UCD and GC candidates (photometrically selected) in the Fornax cluster)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/504/3580/tablea5?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/504/3580/tablea5?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/504/3580/tablea5?GETtext/xml+votable180.050000true54.348865-33.620353060.005555555555555556Cone search capability for table J/MNRAS/504/3580/tablea6 (Catalogue of the UCD candidates with high probability (photometrically selected))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/504/3580/tablea6?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/504/3580/tablea6?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/504/3580/tablea6?GETtext/xml+votable180.050000true54.348865-33.620353060.005555555555555556Cone search capability for table J/MNRAS/504/3580/list (List of fits images)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/504/3580/list?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/504/3580/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/504/3580/list?GETtext/xml+votable180.050000true56.50362-34.494310.0055555555555555565/8632-8633 8635-8636 6/34493 34507 34510-34511 34522-34523 34536-34537 34539 34552-34554 35905 35908-359097.952274030004205e-20 1.7798557115773645e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/504/3580?format=asciiInfrareddefaultJ/MNRAS/504/3580/tablea1Catalogue of the spectroscopically confirmed ultra-compact dwarf galaxies (UCD) and globular clusters (GCs) in the Fornax clusterrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainumagSloan u magnitude (AB)magphot.mag;em.opt.Ufloate_umagrms uncertainty on umagmagstat.error;phot.magfloatgmagSloan g magnitude (AB)magphot.mag;em.opt.Bfloate_gmagrms uncertainty on gmagmagstat.error;phot.magfloatrmagSloan r magnitude (AB)magphot.mag;em.opt.Rfloate_rmagrms uncertainty on rmagmagstat.error;phot.magfloatimagSloan i magnitude (AB)magphot.mag;em.opt.Ifloate_imagrms uncertainty on imagmagstat.error;phot.magfloatJmagJ magnitude (AB)magphot.mag;em.IR.Jfloate_Jmagrms uncertainty on Jmagmagstat.error;phot.magfloatKsmagKs magnitude (AB)magphot.mag;em.IR.Kfloate_Ksmagrms uncertainty on Ksmagmagstat.error;phot.magfloatrh? Measured half-light (effective) radiuspcphys.size.radiusfloatnullableJ/MNRAS/504/3580/tablea2Catalogue of the spectroscopic foreground stars (galaxies farthur than the Fornax Galaxy Cluster)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainumagSloan u magnitude (AB)magphot.mag;em.opt.Ufloate_umagrms uncertainty on umagmagstat.error;phot.magfloatgmagSloan g magnitude (AB)magphot.mag;em.opt.Bfloate_gmagrms uncertainty on gmagmagstat.error;phot.magfloatrmagSloan r magnitude (AB)magphot.mag;em.opt.Rfloate_rmagrms uncertainty on rmagmagstat.error;phot.magfloatimagSloan i magnitude (AB)magphot.mag;em.opt.Ifloate_imagrms uncertainty on imagmagstat.error;phot.magfloatJmagJ magnitude (AB)magphot.mag;em.IR.Jfloate_Jmagrms uncertainty on Jmagmagstat.error;phot.magfloatKsmagKs magnitude (AB)magphot.mag;em.IR.Kfloate_Ksmagrms uncertainty on Ksmagmagstat.error;phot.magfloatJ/MNRAS/504/3580/tablea3Catalogue of the spectroscopic background galaxies (Milky Way stars)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainumagSloan u magnitude (AB)magphot.mag;em.opt.Ufloate_umagrms uncertainty on umagmagstat.error;phot.magfloatgmagSloan g magnitude (AB)magphot.mag;em.opt.Bfloate_gmagrms uncertainty on gmagmagstat.error;phot.magfloatrmagSloan r magnitude (AB)magphot.mag;em.opt.Rfloate_rmagrms uncertainty on rmagmagstat.error;phot.magfloatimagSloan i magnitude (AB)magphot.mag;em.opt.Ifloate_imagrms uncertainty on imagmagstat.error;phot.magfloatJmagJ magnitude (AB)magphot.mag;em.IR.Jfloate_Jmagrms uncertainty on Jmagmagstat.error;phot.magfloatKsmagKs magnitude (AB)magphot.mag;em.IR.Kfloate_Ksmagrms uncertainty on Ksmagmagstat.error;phot.magfloatJ/MNRAS/504/3580/tablea4*The UNKNOWN cataloguerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainindexedDEJ2000Declination (J2000)degpos.eq.dec;meta.mainindexedumagSloan u magnitude (AB)magphot.mag;em.opt.Ufloate_umagrms uncertainty on umagmagstat.error;phot.magfloatgmagSloan g magnitude (AB)magphot.mag;em.opt.Bfloate_gmagrms uncertainty on gmagmagstat.error;phot.magfloatrmagSloan r magnitude (AB)magphot.mag;em.opt.Rfloate_rmagrms uncertainty on rmagmagstat.error;phot.magfloatimagSloan i magnitude (AB)magphot.mag;em.opt.Ifloate_imagrms uncertainty on imagmagstat.error;phot.magfloatJmagJ magnitude (AB)magphot.mag;em.IR.Jfloate_Jmagrms uncertainty on Jmagmagstat.error;phot.magfloatKsmagKs magnitude (AB)magphot.mag;em.IR.Kfloate_Ksmagrms uncertainty on Ksmagmagstat.error;phot.magfloatJ/MNRAS/504/3580/tablea5Catalogue of the UCD and GC candidates (photometrically selected) in the Fornax clusterrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDName (UCD-CAND-NNN for tablea5, FDS-UCD-NN for tablea6)meta.id;meta.maincharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainumagSloan u magnitude (AB)magphot.mag;em.opt.Ufloate_umagrms uncertainty on umagmagstat.error;phot.magfloatgmagSloan g magnitude (AB)magphot.mag;em.opt.Bfloate_gmagrms uncertainty on gmagmagstat.error;phot.magfloatrmagSloan r magnitude (AB)magphot.mag;em.opt.Rfloate_rmagrms uncertainty on rmagmagstat.error;phot.magfloatimagSloan i magnitude (AB)magphot.mag;em.opt.Ifloate_imagrms uncertainty on imagmagstat.error;phot.magfloatJmagJ magnitude (AB)magphot.mag;em.IR.Jfloate_Jmagrms uncertainty on Jmagmagstat.error;phot.magfloatKsmagKs magnitude (AB)magphot.mag;em.IR.Kfloate_Ksmagrms uncertainty on Ksmagmagstat.error;phot.magfloatrh? Measured half-light (effective) radiuspcphys.size.radiusfloatnullableCompThe position of the object in u-i/i-Ks diagram in respect to the completeness contoursstat.fit.goodnessintStarThe likelihood of the object to be in the foregound (star)stat.fit.goodnessintUCDThe likelihood of the object to be a UCD or GCstat.fit.goodnessintGalThe likelihood of the object to be in the background (galaxy, farther than the Fornax cluster)stat.fit.goodnessintJ/MNRAS/504/3580/tablea6Catalogue of the UCD candidates with high probability (photometrically selected)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDName (UCD-CAND-NNN for tablea5, FDS-UCD-NN for tablea6)meta.id;meta.maincharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainumagSloan u magnitude (AB)magphot.mag;em.opt.Ufloate_umagrms uncertainty on umagmagstat.error;phot.magfloatgmagSloan g magnitude (AB)magphot.mag;em.opt.Bfloate_gmagrms uncertainty on gmagmagstat.error;phot.magfloatrmagSloan r magnitude (AB)magphot.mag;em.opt.Rfloate_rmagrms uncertainty on rmagmagstat.error;phot.magfloatimagSloan i magnitude (AB)magphot.mag;em.opt.Ifloate_imagrms uncertainty on imagmagstat.error;phot.magfloatJmagJ magnitude (AB)magphot.mag;em.IR.Jfloate_Jmagrms uncertainty on Jmagmagstat.error;phot.magfloatKsmagKs magnitude (AB)magphot.mag;em.IR.Kfloate_Ksmagrms uncertainty on Ksmagmagstat.error;phot.magfloatrh? Measured half-light (effective) radiuspcphys.size.radiusfloatnullableCompThe position of the object in u-i/i-Ks diagram in respect to the completeness contoursstat.fit.goodnessintStarThe likelihood of the object to be in the foregound (star)stat.fit.goodnessintUCDThe likelihood of the object to be a UCD or GCstat.fit.goodnessintGalThe likelihood of the object to be in the background (galaxy, farther than the Fornax cluster)stat.fit.goodnessintJ/MNRAS/504/3580/listList of fits imagesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension of center (J2000)degpos.eq.ra;meta.mainDEJ2000Declination of center (J2000)degpos.eq.dec;meta.mainscaleScale of the imagearcsec/pixinstr.scalefloatNxNumber of pixels along X-axismeta.numberintNyNumber of pixels along Y-axismeta.numberintsizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitschar