J/AJ/144/11ivo://CDS.VizieR/J/AJ/144/11doi:10.26093/cds/vizier.51440011CDSMason R.E.Lopez-Rodriguez E.Packham C.Alonso-Herrero A.,Levenson N.A.Radomski J.Ramos Almeida C.Colina L.Elitzur M.,Aretxaga I.Roche P.F.Oi N.2017-06-29T08:56:24Z2013-09-12T14:52:31ZCDS support team

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

cds-question@unistra.fractive-galactic-nucleigalaxiesspectroscopyinfrared-photometryspectral-energy-distributionx-ray-sourcesWe present high-resolution mid-infrared (MIR) imaging, nuclear spectral energy distributions (SEDs), and archival Spitzer spectra for 22 low-luminosity active galactic nuclei (LLAGNs; L_bol_<~10^42^erg/s). Infrared (IR) observations may advance our understanding of the accretion flows in LLAGNs, the fate of the obscuring torus at low accretion rates, and, perhaps, the star formation histories of these objects. However, while comprehensively studied in higher-luminosity Seyferts and quasars, the nuclear IR properties of LLAGNs have not yet been well determined. We separate the present LLAGN sample into three categories depending on their Eddington ratio and radio emission, finding different IR characteristics for each class. (1) At the low-luminosity, low-Eddington-ratio (log L_bol_/L_Edd_< -4.6) end of the sample, we identify "host-dominated" galaxies with strong polycyclic aromatic hydrocarbon bands that may indicate active (circum-)nuclear star formation. (2) Some very radio-loud objects are also present at these low Eddington ratios. The IR emission in these nuclei is dominated by synchrotron radiation, and some are likely to be unobscured type 2 AGNs that genuinely lack a broad-line region. (3) At higher Eddington ratios, strong, compact nuclear sources are visible in the MIR images. The nuclear SEDs of these galaxies are diverse; some resemble typical Seyfert nuclei, while others lack a well-defined MIR "dust bump." Strong silicate emission is present in many of these objects. We speculate that this, together with high ratios of silicate strength to hydrogen column density, could suggest optically thin dust and low dust-to-gas ratios, in accordance with model predictions that LLAGNs do not host a Seyfert-like obscuring torus. We anticipate that detailed modeling of the new data and SEDs in terms of accretion disk, jet, radiatively inefficient accretion flow, and torus components will provide further insights into the nuclear structures and processes of LLAGNs.2012AJ....144...11Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/144/11CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/730/19 : IR spectra and SEDs for starbursts and AGNs (Sargsyan+, 2011)J/ApJS/187/135 : SEDs of weak AGNs associated with LINERs (Eracleous+, 2010)J/ApJS/187/64 : The simultaneous optical-to-X-ray SED of AGNs (Grupe+, 2010)J/ApJ/725/2270 : Mid-IR emission lines in AGNs (Pereira-Santaella+, 2010)J/ApJ/683/114 : IRS spectra of faint IRAS sources (Sargsyan+, 2008)J/ApJ/642/673 : IR-selected obscured AGN candidates (Polletta+, 2006)J/A+A/357/839 : AGN 2.5-11um spectroscopy (Clavel+, 2000)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/144/11https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/144/11http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/144/11https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/144/11https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/144/11http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/144/11GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/144/11/galaxies (Properties of the low-luminosity active galactic nuclei (LLAGNs))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/144/11/galaxies?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/144/11/galaxies?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/144/11/galaxies?GETtext/xml+votable180.050000true40.2699939-8.25576440.0055555555555555566/5975 5976 7606 10475 10817 10856 10924 10977 20000 25083 26091 26338 27255 27426 27714 27765 27767 27773 27914 28495 35993 36785https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/144/11?format=asciiX-rayInfrareddefaultJ/AJ/144/11/galaxiesProperties of the low-luminosity active galactic nuclei (LLAGNs)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNGCNGC galaxy numbermeta.id;meta.mainintprimaryONameOther galaxy namemeta.idcharMTypeMorphological typesrc.morph.typecharAGNtAGN type (LL=low-luminosity, S=Seyfert)src.classcharDist? DistanceMpcpos.distance;pos.heliocentricfloatnullablelogMBH[7.1/9]? log of black hole masslog(solMass)phys.massfloatnullablelogER? log of the Eddington ratio L_bol_/L_Edd_phys.luminosity;arith.ratiofloatnullableRx[-5.3/-1.1]? Radio to X emission ratio R_X_ (1)phys.luminosity;arith.ratiofloatnullableCatCategory depending on the Eddington ratio and radio emission (3)src.classnullableSMBHEvidence that the galaxy hosts an actively accreting supermassive black hole (SMBH), with reference. See Section 2 for more details (2)meta.codeSEDSED plot(from table7)meta.ref.urlcharSimbadSimbad column added by the CDSmeta.refcharNEDSimbad column added by the CDSmeta.refcharFpsf/F2? Ratio of mid-IR PSF-scaling flux to that obtained in a 2" aperture (see Section 3.1 for details) (4)phot.flux;arith.ratiofloatnullableS? Strength of the ~10{mu}m silicate feature S_10_ (see Section 4.2 for details) (5)spect.line.intensityfloatnullablealpha? Near- to mid-IR spectral index {alpha}_IR_, F({nu}){prop.to}{nu}^-{alpha}^, for objects possessing at least one mid-IR and one H-band photometric point. See Section 4.3 (4)spect.indexfloatnullablel_logLMIRUpper limit on log(LMIR)meta.code.errorcharlogLMIR[39.8/42.7] log of mid-infrared luminosity (4)log(1e-07W)phys.luminosity;em.IRfloatlogLX[38.8/41.4] absorption-corrected 2-10keV X-ray luminosity (erg/s); see Section 4.3log(1e-07W)phys.luminosity;em.X-rayfloatr_logLXReference for logLX (X-ray luminosity) and for NH (HI column density), in refs. dat filemeta.ref;pos.frameintl_NHUpper limit on NHmeta.code.errorcharNH? HI column density1e+22cm**-2phys.columnDensityfloatnullableCTIndicates whether the galaxy is suspected to be Compton-thick (Y, N or ?) (6)meta.codecharr_CT? Reference for CT, in refs.dat filemeta.ref;pos.frameintnullable_RAPositions from SIMBAD database (right ascension part)degpos.eq.ra;meta.main_DEPositions from SIMBAD database (declination part)degpos.eq.dec;meta.mainJ/AJ/144/11/photoPhotometric results (near- and mid-IR)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNGCNGC galaxy numbermeta.id;meta.mainintf_NGCFlag on NGC (1)meta.codecharFltFilter used (4)instr.setup;instr.filtercharl_F2Upper limit on F2meta.code.errorcharF2[3/257] Photometric flux in 2" diameter aperturemJyphot.flux.density;instr.fovinte_F2? Error in F2mJystat.errorintnullableFpsf[2/197]? PSF-scaling photometry (2)mJyphot.fluxintnullablef_Fpsf[e] Questionable Fpsf (3)meta.codechare_Fpsf? Error in FpsfmJystat.errorintnullableFWHMg? FWHM (Moffat) of galactic nucleusarcsecphys.angSizefloatnullablef_FWHMg[f] Gaussian FWHMg (3)meta.codecharFWHMsFWHM (Moffat) of standard stararcsecphys.angSizefloatf_FWHMs[f] Gaussian FWHMs (3)meta.codecharJ/AJ/144/11/table6Intrinsic X-Ray luminosity estimates for suspected Compton-thick low-luminosity active galactic nuclei (LLAGNs)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNGCNGC galaxy numbermeta.id;meta.mainintlogLX[39/41.1] Intrinsic luminosity estimates as given in Table 5 (Column logLX), from spectral fitting of high-resolution X-ray data (1)1e-07Wphys.luminosity;em.X-rayfloatlogLX([OIII])[40.6/42.9] Intrinsic "corrected" luminosity from Gonzalez-Martin et al. (2009A&A...506.1107G) and Panessa et al. (2006A&A...455..173P) (2)1e-07Wphys.luminosity;em.X-rayfloatlogLX([OIV])[39.3/41.6]? Intrinsic luminosity estimates based on L_bol,AGN_-L_[OIV]_ relation of Goulding et al. (2010MNRAS.406..597G) (3)1e-07Wphys.luminosity;em.X-rayfloatnullableJ/AJ/144/11/table7Spectral energy distribution datarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNGCNGC galaxy numbermeta.id;meta.mainintnuFrequency of observation {nu}Hzem.freq;obsdoublel_LumLimit flag on Lummeta.code.errorcharLumThe {nu}L_{nu}_ luminosity; in erg/s1e-07Wphys.luminositydoubleAperAperture/resolution (1)arcsecphys.angSizecharFacilityTelescope/instrumentmeta.notecharRefReference(s), in refs.dat filemeta.ref;pos.frame;meta.filecharJ/AJ/144/11/refsReferencesComCommentsmeta.notecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRef[1/110] Reference numbermeta.id;meta.mainintBibCodeBibliographic codemeta.bib.bibcodecharAutAuthor's namemeta.bib.authorchar