J/A+A/681/A97ivo://CDS.VizieR/J/A+A/681/A97doi:10.26093/cds/vizier.36810097CDSArcodia R.Merloni A.Comparat J.Dwelly T.Seppi R.Zhang Y.,Buchner J.Georgakakis A.Haberl F.Igo Z.Kyritsis E.Liu T.,Nandra K.Ni Q.Ponti G.Salvato M.Ward C.Wolf J.Zezas A.2024-11-28T20:05:59Z2024-07-18T15:37:27ZCDS support team

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

cds-question@unistra.frx-ray-sourcesgalaxiesblack-holesFinding massive black holes (MBHs, M_BH_~10^4^-10^7^M_{sun}_) in the nuclei of low-mass galaxies (M*<=10^10^M_{sun}_) is crucial to constrain seeding and growth of black holes over cosmic time, but it is particularly challenging due to their low accretion luminosities. Variability selection via long-term photometric ultraviolet, optical, or infrared (UVOIR) light curves has proved effective and identifies lower-Eddington ratios compared to broad and narrow optical spectral lines searches. In the inefficient accretion regime, X-ray and radio searches are effective, but they have been limited to small samples. Therefore, differences between selection techniques have remained uncertain. Here, we present the first large systematic investigation of the X-ray properties of a sample of known MBH candidates in dwarf galaxies. We extracted X-ray photometry and spectra of a sample of ~200 UVOIR variability-selected MBHs and significantly detected 17 of them in the deepest available SRG/eROSITA image, of which four are newly discovered X-ray sources and two are new secure MBHs. This implies that tens to hundreds of LSST MBHs will have SRG/eROSITA counterparts, depending on the seeding model adopted. Surprisingly, the stacked X-ray images of the many non-detected MBHs are incompatible with standard disk-corona relations, typical of active galactic nuclei, inferred from both the optical and radio fluxes. They are instead compatible with the X-ray emission predicted for normal galaxies. After careful consideration of potential biases, we identified that this X-ray weakness needs a physical origin. A possibility is that a canonical X-ray corona might be lacking in the majority of this population of UVOIR-variability selected low-mass galaxies or that unusual accretion modes and spectral energy distributions are in place for MBHs in dwarf galaxies. This result reveals the potential for severe biases in occupation fractions derived from data from only one waveband combined with SEDs and scaling relations of more massive black holes and galaxies.2024A&A...681A..97Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/681/A97CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/896/10 : NSA low-mass galaxies with long-term PTF observationsJ/ApJ/894/24 : Optical variability of AGN from the HSC SSP surveyhttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/681/A97https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/681/A97http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/681/A97https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/681/A97https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/681/A97http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/681/A97GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/681/A97/tableb1 (Input MBH candidates from optical/IR/UV variability and related eROSITA information from aperture photometry and spectroscopy)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/681/A97/tableb1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/681/A97/tableb1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/681/A97/tableb1?GETtext/xml+votable180.050000true48.25895-0.6863790.005555555555555556Cone search capability for table J/A+A/681/A97/tableb2 (eRASS:4 detections matched with XMM-Newton, Chandra, ROSAT and Swift-XRT)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/681/A97/tableb2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/681/A97/tableb2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/681/A97/tableb2?GETtext/xml+votable180.050000true48.25895-0.686378890.0055555555555555565/6814 8847 6/4181 4314 4352 4441 4444 4447 4453 4490-4492 4577 4636 4652 4654 4660 4676 4710 4774 4807 4817 4826 4832 4854 4892 4936 4991 5009 5011 5109 5133 5148 5364 5645-5646 5657 5660 5730 6222 6270 6401 6451 6462 6481 6536 8195 8226 8866 10248 10274 21878 21997 22355 22361 22746 23043 23203 23207 25974 25992 26006 26050 26074 26077 26079 26157 26174 26265 26310 26342 26349 26362 26401-26402 26457 26487 26501 26503 26528-26529 26534 26536-26537 26539 26545 26557 26559-26560 26595 27052 27116 27247 27317 27333 27348 27384 27425 27486 27501 27566 27580 27584 27669 27706 27713 27719 27740 27742 27771 27829 27858 27860 27866 27872 27968 27972 27997 28050 28064 28071 28148 28154 28251 28377 28425 28478 28505 28522 28576 28583 35382-35383 35385 35387 35473 35476 35931 35934-35935 35953 35956-35957 36342 36734 36785https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/681/A97?format=asciiX-raydefaultJ/A+A/681/A97/tableb1Input MBH candidates from optical/IR/UV variability and related eROSITA information from aperture photometry and spectroscopyrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Input right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Input declination (J2000)degpos.eq.dec;meta.mainzRedshiftsrc.redshiftfloatM*Stellar masssolMassphys.massfloatRefReference for input coordinates, redshift and stellar mass (1)meta.ref;pos.framecharPB1eRASS1 no-source probability PB (Eq. 1) (2)stat.fit.goodnesscharl_LX1Limit flag on LX1meta.code.errorcharLX1? eRASS1 median logarithmic X-ray luminosity in the rest-frame 0.2-2.0keV range for detected source or 1{sigma} upper limit for non detected source (3)log(1e-07W)phys.luminosity;em.X-rayfloatnullableLX1-16? eRASS1 L0.2-2.0keV 16th percentile for detected sourcelog(1e-07W)phys.luminosity;em.X-rayfloatnullableLX1-84? eRASS1 L0.2-2.0keV 84th percentile for detected sourcelog(1e-07W)phys.luminosity;em.X-rayfloatnullableLX1-1? eRASS1 L0.2-2.0keV 1st percentile for detected sourcelog(1e-07W)phys.luminosity;em.X-rayfloatnullableLX1-99? eRASS1 L0.2-2.0keV 99th percentile for detected sourcelog(1e-07W)phys.luminosity;em.X-rayfloatnullableLX1-3s? eRASS1 logarithmic X-ray luminosity in the rest-frame 0.2-2.0keV range 3{sigma} upper limit for non detected sourcelog(1e-07W)phys.luminosity;em.X-rayfloatnullablePB4eRASS4 no-source probability PB (Eq. 1) (2)stat.fit.goodnesscharl_LX4Limit flag on LX4meta.code.errorcharLX4? eRASS4 median logarithmic X-ray luminosity in the rest-frame 0.2-2.0keV range for detected source or 1{sigma} upper limit for non detected source (3)log(1e-07W)phys.luminosity;em.X-rayfloatnullableLX4-16? eRASS4 L0.2-2.0keV 16th percentile for detected sourcelog(1e-07W)phys.luminosity;em.X-rayfloatnullableLX4-84? eRASS4 L0.2-2.0keV 84th percentile for detected sourcelog(1e-07W)phys.luminosity;em.X-rayfloatnullableLX4-1? eRASS4 L0.2-2.0keV 1st percentile for detected sourcelog(1e-07W)phys.luminosity;em.X-rayfloatnullableLX4-99? eRASS4 L0.2-2.0keV 99th percentile for detected sourcelog(1e-07W)phys.luminosity;em.X-rayfloatnullableLX2-3s? eRASS2 logarithmic X-ray luminosity in the rest-frame 0.2-2.0keV range 3{sigma} upper limit for non detected sourcelog(1e-07W)phys.luminosity;em.X-rayfloatnullableJ/A+A/681/A97/tableb2eRASS:4 detections matched with XMM-Newton, Chandra, ROSAT and Swift-XRTrecnoRecord 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.mainLX4eRASS4 median logarithmic X-ray luminosity in the rest-frame 0.2-2.0keV rangelog(1e-07W)phys.luminosity;em.X-rayfloatLX4-16eRASS4 L0.2-2.0keV 16th percentilelog(1e-07W)phys.luminosity;em.X-rayfloatLX4-84eRASS4 L0.2-2.0keV 84th percentilelog(1e-07W)phys.luminosity;em.X-rayfloatLX4-1eRASS4 L0.2-2.0keV 1st percentilelog(1e-07W)phys.luminosity;em.X-rayfloatLX4-99eRASS4 L0.2-2.0keV 99th percentilelog(1e-07W)phys.luminosity;em.X-rayfloatXMM[Y-] Match with XMM source ?meta.codecharSwift[Y-] Match with Swift source ?meta.codecharComCommentsmeta.notecharNote[*] * for sources with no previous X-ray detectionsmeta.notecharChandra[Y-] Match with Chandra source ?meta.codecharROSAT[Y-] Match with ROSAT source ?meta.codechar