J/A+A/694/A127ivo://CDS.VizieR/J/A+A/694/A127doi:10.26093/cds/vizier.36940127CDSBernal S.Sanchez-Saez P.Arevalo P.Bauer F.E.Lira P.Sotomayor B.2025-05-21T20:01:21Z2025-02-11T11:58:30ZCDS support team

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

cds-question@unistra.fractive-galactic-nucleiredshiftedline-intensitiesvisible-astronomyspectroscopyThe origins of supermassive black holes (SMBHs) at the centers of massive galaxies are a topic of intense investigation. One way to address this subject is to identify the seeds of SMBHs as intermediate-mass black holes (IMBHs; 100M_{sun}_<MBH<10^6^M_{sun}_). IMBHs are expected to be found at the centers of low stellar mass galaxies (LSMGs). Our goal is to complete the census of SMBHs in LSMGs. In this work our aim is to establish the purity of active galactic nucleus (AGN) selection by algorithms based on optical variability and to characterize the black hole population found through this method. We used random forest algorithms to classify all objects in a large portion of the sky, using optical light curves obtained from, or built from images provided by, the Zwicky Transient Facility (ZTF). We compared different selection sets based on alerts (flux changes with at least 5{sigma} significance) or complete light curves derived from different photometric selection algorithms. The AGN candidates thus selected were cross-matched with objects in the NASA-Sloan Atlas (NSA) of local galaxies, with M*<2x10^10^M_{sun}_. The AGN nature of these candidates was verified and characterized using archival optical spectra from SDSS. We further established the fraction of candidates with counterparts in the eROSITA Data Release 1 catalog of X-ray sources. From an initial sample of 506 candidates, 415 have good-quality spectra. Among these 415 objects we found significant broad Balmer lines in the spectra for 86% (357) of the candidates. When considering BPT classifications, five additional candidates were confirmed, resulting in 87% (362) confirmed candidates. Specifically, broad Balmer lines were detected in 94%-98% of the AGN candidates selected from complete light curves and in 80% of those selected from the less frequent ZTF alerts. The black hole masses estimated from the spectra range from 2.2x10^6^M_{sun}_ to 4.2x10^7^M_{sun}_, reaching lower values for the candidates selected using the more sensitive light curves. The black hole masses obtained cluster around 0.1% of the stellar mass of the host from the NSA catalog. Two-thirds of the AGN candidates are classified as Seyfert or composite by their narrow emission line ratios (BPT diagnostics), while the rest are star-forming. Almost all the candidates classified as Seyfert and over 50% of those classified as star-forming have significant broad emission lines (BELs). We found X-ray counterparts for 67% of the candidates that fall in the footprint of the eROSITA-DE DR1. Considering only the candidates with significant BELs, the matches increase to 75%, regardless of where they appear in the BPT diagnostics diagrams.2025A&A...694A.127Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/694/A127CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/682/A34 : SRG/eROSITA all-sky survey catalogs (eRASS1) (Merloni+, 2024)https://www.sdss4.org/dr17/manga/manga-target-selection/nsa/ :https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/694/A127https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/694/A127http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/694/A127https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/694/A127https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/694/A127http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/694/A127GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/694/A127/table4 (Values of the different estimated magnitudes for 415 AGN candidates)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/694/A127/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/694/A127/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/694/A127/table4?GETtext/xml+votable180.050000true141.447185.042131110.0055555555555555566/4119 4122 4139 4147 4151 4166 4169 4221 4237 4255 4343 4359 4400 4449-4450 4473 4496 4535 4547 4564 4613 4647 4705 4731 4829 4865 4898 4965 4972 5061 5076 5109 5131 5153 5181 5221 5270 5330 5344 5355 5359 5378 5405 5481 5488 5514 5536 5555 5566 5578 5584 5600 5604 5652 5750 5853 5885 5926 5953 5959 5964 5983 5989 6065 6076 6087 6091 6097 6109 6208 6211 6220 6224 6484 6529 6571 6601 6933 7193 7219 7228 7232 7247 7251 7267 7298 7328 7360 7466 7476 7521 7554 7587 8210-8211 8213 8220 8222 8225 8231-8232 8249-8250 8255 8262 8279 8292 8303 8370 8391 8402 8408 8456 8474 8477 8555 8579 8589 8606 8618 8632 8635 8669 8716 8759 8777 8866 8882 8885 8905-8906 8908 8918 8935 8947 8952 8959 8992 9002 9037 9141 9151 9156 9199 9203 9232 9242 9260 9266 9310 9341 9407 9456 9461 9467 9601 9643 9735 9774 9831 9863 9930 9957 9978 9983 10248 10280 10291 10298 10310 10322 10338 10358 10384 10388 10390 10438 10454 10466-10467 10511 10530 10541 10576 10627 10686 10689 10746 10751 10846 10869 10959 10997 11002 11064-11065 11069 11071 11086 11103 11117 11191 11201 11204 11214 11217 11243 11250 11321 11343 11347 11415 11437 11590 11785 11873 11875 17315 17470 17500 17553 17763 17773 17858 17983 18006 18028 18066 18089-18090 18302 18367 18515 18583 18586 18838 18844 19048 19050 19100 19115 19319 19328 19389 19678 19741 19763 19842 19945 21885 21999 22009 22718 22762 23104 23202 23212 25585 25843 25847 25852 25918-25919 25948 25958 25965-25966 25968 25973 25986 25991 26022 26049 26070 26167 26188 26207 26209 26226 26260 26264 26277 26296 26310 26323-26324 26329 26341 26355 26358 26364 26388 26407 26411 26414 26430 26438-26439 26467 26508 26525 26585 26606 26954 26966 26970 26990 27035 27043 27087 27101-27102 27225 27227 27230 27236 27293 27303 27351 27364 27370 27380 27386 27390 27411 27471 27484 27501 27509 27537 27562 27565 27620 27687 27691 27693 27698 27715 27726 27732 27734 27749 27781 27786 27800 27805 27815 27821 27827 27851 27857 27863 27868 27878-27879 27912-27913 27920 27947 27949 27976 28059 28100 28200 28225 28233 28279 28300 28307 28376 28413 28449 28477 28484 28492 28505 28515-28516 28518 28527 28535 28569 28662 28668 31323 31370 31378 31410 31427 31448 31459 31468 31485 31626 31637 31649 31679 32399 36763 36785 49009 49097 49122https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/694/A127?format=asciiOpticaldefaultJ/A+A/694/A127/table4Values of the different estimated magnitudes for 415 AGN candidatesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension (J2000) (RA)degpos.eq.ra;meta.mainBFluxHanrFluxHanr 84th (Flux_Ha_nr_p84)1e-20W.m**-2phot.flux;em.line.HalphadoubleFlux[NII]Flux [NII] NEL (Flux_[NII]) (3)1e-20W.m**-2phot.fluxdoubleDEJ2000Declination( J2000) (Dec)degpos.eq.dec;meta.mainzNSARedshift in NSAv1.0.1 (Redshift_NSA)src.redshift;pos.heliocentricdoubleMSersicGalaxy mass (SERSIC_MASS) (1)solMassphys.massdoubleSDSSClassSDSS pipeline class (SDSS_class)meta.code.classcharzRedshift in SDSS (Z)src.redshiftdoubleZTFAlertsset[0/1] Included in the set 1=yes 0=no (ZTF_Alerts_set)meta.noteintForcedPhotset[0/1] Included in the set 1=yes 0=no (Forced_Photometry_set)meta.noteintZTFDR11gband[0/1] Included in the set 1=yes 0=no (ZTFDR11_g_band)meta.noteintZTFDR11rband[0/1] Included in the set 1=yes 0=no (ZTFDR11_r_band)meta.noteintFWHMbrBEL component FWHM (FWHM_br) (2)km/sspect.line.widthdoublebFWHMbrFWHMbr percentil 16 (FWHM_br_p16)km/sspect.line.widthdoubleBFWHMbrFWHMbr percentil 84 (FWHM_br_p84)km/sspect.line.widthdoubleEWHabrEquivalent Width Ha (EW_Ha_br) (2)spect.line.eqWidthfloatbEWHabrEWHabr percentil 16 (EW_Ha_br_p16)spect.line.eqWidthfloatbFlux[NII]Flux[NII] 16th (Flux_[NII]_p16)1e-20W.m**-2phot.fluxdoubleBFlux[NII]Flux[NII] 84th (Flux_[NII]_p84)1e-20W.m**-2phot.fluxdoubleFlux[SII]dFlux [SII]d NEL (Flux_[SII]d) (3)1e-20W.m**-2phot.fluxdoublebFlux[SII]dFlux[SII]d 16th (Flux_[SII]d_p16)1e-20W.m**-2phot.fluxdoubleBFlux[SII]dFlux[SII]d 84th (Flux_[SII]d_p84)1e-20W.m**-2phot.fluxdoubleFlux[OI]Flux [OI] NEL (Flux_[OI]) (3)1e-20W.m**-2phot.fluxdoublebFlux[OI]Flux[OI] 16th (Flux_[OI]_p16)1e-20W.m**-2phot.fluxdoubleBFlux[OI]Flux[OI] 84th (Flux_[OI]_p84)1e-20W.m**-2phot.fluxdoubleBPT[NII]HaBPT class (BPT_[NII]_Ha) (4)meta.code.classcharBEWHabrEWHabr percentil 84 (EW_Ha_br_p84)spect.line.eqWidthfloatFluxHabrFlux Halpha BEL (Flux_Ha_br) (2)1e-20W.m**-2phot.flux;em.line.HalphadoublebFluxHabrFluxHabr 16th (Flux_Ha_br_p16)1e-20W.m**-2phot.flux;em.line.HalphadoubleBFluxHabrFluxHabr 84th (Flux_Ha_br_p84)1e-20W.m**-2phot.flux;em.line.HalphadoubleLum5100AGN-cont luminosity at 5100{AA} (Lum_5100)1e-07Wphys.luminositydoublebLum5100Lum5100 16th (Lum_5100_p16)1e-07Wphys.luminositydoubleBLum5100Lum5100 84th (Lum_5100_p84)1e-07Wphys.luminositydoubleBHMassBH Mass using Eq.1 (BH_Mass)log(solMass)phys.massfloate_BHMassBH Mass negative error (BH_Mass_e1)log(solMass)stat.errorfloatE_BHMassBH Mass positive error (BH_Mass_e2)log(solMass)stat.error;stat.maxfloatLREddEddintong Ratio (LREdd)phys.luminosity;arith.ratiofloate_LREddLREdd negative error (LREdd_e1)stat.errorfloatE_LREddLREdd positive error (LREdd_e2)stat.error;stat.maxfloatFluxHbbrFlux Hbeta BEL (Flux_Hb_br) (2)1e-20W.m**-2phot.flux;em.line.HbetadoublebFluxHbbrFluxHabr 16th (Flux_Hb_br_p16)1e-20W.m**-2phot.flux;em.line.HbetadoubleBFluxHbbrFluxHabr 84th (Flux_Hb_br_p84)1e-20W.m**-2phot.flux;em.line.HbetadoubleEWHbbrEquivalent Width Hb (EW_Hb_br) (2)spect.line.eqWidthfloatbEWHbbrEWHbbr 16th (EW_Hb_br_p16)spect.line.eqWidthfloatBEWHbbrEWHbbr 84th (EW_Hb_br_p84)spect.line.eqWidthfloatFlux[OIII]Flux [OIII] NEL (Flux_[OIII]) (3)1e-20W.m**-2phot.fluxdoublebFlux[OIII]Flux[OIII] 16th (Flux_[OIII]_p16)1e-20W.m**-2phot.fluxdoubleBFlux[OIII]Flux[OIII] 84th (Flux_[OIII]_p84)1e-20W.m**-2phot.fluxdoubleFluxHbnrFlux Hbeta NEL (Flux_Hb_nr) (3)1e-20W.m**-2phot.flux;em.line.HbetadoublebFluxHbnrFluxHbnr 16th (Flux_Hb_nr_p16)1e-20W.m**-2phot.flux;em.line.HbetadoubleBFluxHbnrFluxHbnr 84th (Flux_Hb_nr_p84)1e-20W.m**-2phot.flux;em.line.HbetadoubleFluxHanrFlux Halpha NEL (Flux_Ha_nr) (3)1e-20W.m**-2phot.flux;em.line.HalphadoublebFluxHanrFluxHanr 16th (Flux_Ha_nr_p16)1e-20W.m**-2phot.flux;em.line.HalphadoubleBPT[SII]HaBPT class (BPT_[SII]_Ha) (4)meta.code.classcharBPT[OI]HaBPT class (BPT_[OI]_Ha) (4)meta.code.classcharrAGNc5100AGN/continuum at 5100{AA} (rAGN_c5100)phys.luminosityfloatAGNslopeAGN component slope (AGN_slope)meta.crypticfloatBHMassHaBH Mass from Ha-Lum (BH_Mass_(Ha))log(solMass)phys.massfloatLHatotal? NEL+BEL Luminosity (LHa_total)1e-07Wphys.luminosity;em.line.HalphadoublenullableeRASSIAUNAME in eRASSv1.1, 1eRASS JHHMMSS.s+DDMMSS (eRASS_IAUNAME)meta.idcharFlux2.8keV? eRASS ML_FLUX_P4+P5 (Flux_2_8_keV) (5)mW.m**-2phot.flux;em.X-raydoublenullableLum2.8keV? Luminosity for 2-8keV (Lum_2_8_keV)1e-07Wphys.luminosity;em.X-raydoublenullableFitModelModel name used to fit (Fitted_Model)meta.id;stat.fitcharFFparamFixed parameters (FF_parameters) (6)meta.id;stat.fitcharNameObject ID in NSAv1.0.1, JHHMMSS.ss+DDMMSS.s (IAUNAME)meta.id;meta.maincharSimbadNameSimbad column added by the CDSmeta.idcharnullable