J/A+A/702/A136ivo://CDS.VizieR/J/A+A/702/A136doi:10.26093/cds/vizier/bc-ny/lbdgCDSJunaisRuiz Cejudo I.Guerra Arencibia S.Trujillo I.Alarcon M.R.,Serra-Ricart M.Knapen J.H.Duc P.-A.2026-08-03T06:57:46Z2025-10-15T12:33:27ZCDS support team

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

cds-question@unistra.fractive-galactic-nucleiinfrared-photometryvisible-astronomybroad-band-photometryGiant Low Surface Brightness (GLSB) galaxies are extreme disk systems with exceptionally large sizes and low stellar densities. Their formation and evolution remain poorly constrained due to the challenges of detecting their faint disks. We present deep, multi-band optical imaging of Malin 2, a prototypical GLSB galaxy, with the newly commissioned Two-meter Twin Telescope (TTT) at the Teide Observatory. Our g, r, and i-band data reach surface brightness depths of 30.3, 29.5, and 28.2mag/arcsec^2^, tracing the stellar disk of Malin 2 to nearly 110kpc. We detect new diffuse structures, including a prominent emission in the northwest coincident with the HI distribution, and a faint spiral arm-like feature in the southeast. We also identify a very faint dwarf galaxy, TTT-d1 (g-band central surface brightness of nearly 26mag/arcsec^2^), about 130kpc southeast of Malin 2, possibly its first known satellite ultra-diffuse galaxy. A multi-directional wedge photometric analysis of Malin 2 shows strong azimuthal variations in its stellar disk. Compared with nearby spirals and other GLSBs, Malin 2 lies at the extreme end in radial extent and stellar mass surface density. The overlap between the asymmetric stellar emission and a lopsided HI distribution suggests contributions from tidal interactions in the formation of the giant disk of Malin 2. Our results highlight the importance of ultra-deep, wide-field imaging in understanding the structural complexity of giant LSB galaxies. Upcoming surveys such as LSST will be crucial to determine whether the features we observe in Malin 2 are common to other giant LSB disk galaxies.2025A&A...702A.136Jhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/702/A136CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/702/A136https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/702/A136http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/702/A136https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/702/A136https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/702/A136http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/702/A136GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/702/A136/list (List of fits images)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/702/A136/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/702/A136/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/702/A136/list?GETtext/xml+votable180.050000true159.9688820.847060.005555555555555556Associated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/702/A1366/28334https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/702/A136?format=asciiOpticalInfrareddefaultJ/A+A/702/A136/listList of fits imagesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameNamemeta.id;meta.maincharRAJ2000Right 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.numberintObs.dateObservation datestime.epoch;obsnullablesizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitschar