J/A+A/702/A42ivo://CDS.VizieR/J/A+A/702/A42doi:10.26093/cds/vizier/bc-ny/lecCDSGrishin K.A.Chilingarian I.V.Combes F.Bauer F.E.Toptun V.A.,Katkov I.Yu.Fabricant D.Kolganov F.Graham A.W.2026-08-03T06:58:26Z2025-10-01T08:40:38ZCDS support team

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

cds-question@unistra.frseyfert-galaxiesgalaxiesspectroscopyvisible-astronomyinfrared-astronomyLow-mass active galactic nuclei (AGNs) can provide important constraints on the formation and evolution of supermassive black holes (SMBHs), which stands as a central challenge in modern cosmology. To date, only small samples of intermediate-mass black holes (IMBHs, M(BH)<10^5^M_{sun}_) and "lesser" SMBHs (LSMBHs, M(BH)<10^6^M_{sun}_) have been identified. Our present study of NGC 3259 at D=27 Mpc with the Binospec integral field unit (IFU) spectrograph complemented with Keck Echelle Spectrograph and Imager observations demonstrates the strong capability and necessity for spectroscopic follow-up studies. NGC 3259 hosts a black hole (BH) with a mass of M(BH)=(2.0-4.9)*10^5^M_{sun}_ from multi-epoch spectroscopic data, which is accreting at 1% of the Eddington limit, as suggested by the analysis of archival XMM-Newton observations. It is the second-nearest broad-line low-mass AGN after the archetypal galaxy NGC 4395. The spectroscopic data reveal a variable broad Ha profile likely resulting from asymmetrically distributed broad-line region (BLR) clouds or BLR outflow events. X-ray observations and the absence of an optical power-law continuum suggest partial obscuration of the accretion disk and hot corona by a dust torus. We estimated that Sloan Digital Sky Survey (SDSS) observations would only have the capacity to detect similar objects up to D=35Mpc. A detailed photometric analysis of NGC 3259 using HST images provides a central spheroid stellar mass estimate that is 20 times lower than expected, based on the M(BH) - M(sph) relation, making this galaxy a significant outlier. This discrepancy suggests divergent growth pathways for the central BH and spheroid, potentially influenced by the potential presence of a bar in the galaxy. Finally, we demonstrate that the DESI and 4MOST surveys will detect low-accretion-rate IMBHs and LSMBHs, while the sensitivity of future X-ray instruments (such as AXIS and Athena) will secure their classification.2025A&A...702A..42Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/702/A42CatalogResearchIsServedByTAP 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/A42https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/702/A42http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/702/A42https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/702/A42https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/702/A42http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/702/A42GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/702/A42/list (List of fits files)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/702/A42/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/702/A42/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/702/A42/list?GETtext/xml+votable180.050000true158.1452565.04108330.005555555555555556Associated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/702/A426/7485https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/702/A42?format=asciiOpticalInfrareddefaultJ/A+A/702/A42/listList of fits filesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Righ ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainNxNumber of pixels along X-axismeta.numberintNyNumber of pixels along Y-axismeta.numberintObs.dateObservation datestime.epoch;obsnullablebAWAVLower value of wavelength interval0.1nmem.wlfloatBAWAVUpper value of wavelength interval0.1nmem.wldoubledAWAVWavelength resolution0.1nmspect.resolutionfloatsizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitschar