J/A+A/692/A205ivo://CDS.VizieR/J/A+A/692/A205doi:10.26093/cds/vizier.36920205CDSBaczko A.-K.Kadler M.Ros E.Fromm M. C.Wielgus M.Perucho M.,Krichbaum P. T.Balokovic M.Blackburn L.Chan C.Issaoun S.,Janssen M.Ricci L.Event Horizon Telescope Collaboration2025-02-26T20:02:25Z2024-12-17T10:56:59ZCDS support team

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

cds-question@unistra.frgalaxiesradio-continuum-emissionMany active galaxies harbor powerful relativistic jets. The detailed mechanisms of their formation and acceleration remain poorly understood. To investigate the area of jet acceleration and collimation with the highest available angular resolution we have studied the innermost region of the bipolar jet in the nearby LINER galaxy NGC 1052. We combined observations of NGC 1052 taken with the VLBA, the GMVA and the EHT during one week in spring 2017. Our study focuses on the size and continuum spectrum of the innermost region containing the central engine and the footpoints of both jets. We employ a synchrotron-self absorption model to fit the continuum radio spectrum and combine size measurements from close to the central engine out to ~1pc to study jet collimation. For the first time NGC 1052 was detected with the EHT, providing a size of the central region in-between both jet bases of 43uas perpendicular to the jet axes, corresponding to just around 250 RS (Schwarzschild radii). This size estimate supports previous studies of the jets expansion profile which suggest two breaks of the profile at around 3x10^3^RS and 1x10^4^RS distances to the core. Furthermore, we estimate the magnetic field to be 1.25 Gauss at a distance of 22uas from the central engine by fitting a synchrotron-self absorption spectrum to the innermost emission feature, which shows a spectral turn-over at ~130GHz. Assuming a purely poloidal magnetic field this implies an upper limit on the magnetic field strength at the event horizon of 2.6x10^4^Gauss, which is consistent with previous measurements. The complex and low brightness, double-sided jet structure in NGC 1052 makes it challenging to detect the source at millimeter wavelength. However, our first EHT observations demonstrated that detection is possible up to at least 230GHz. This enabled us to glimpse through the dense surrounding torus into the innermost central region where the jets are formed, to finally resolve this region and to give improved constraints on its expansion and magnetic field strength.2024A&A...692A.205Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/692/A205CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/692/A205https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/692/A205http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/692/A205https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/692/A205https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/692/A205http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/692/A205GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/692/A205/tableb (Fit parameters and uncertainties of 1.6, 5.0, 8.4, 15.3, 22.2, and 43.1GHz VLBA and 86 GHz GMVA observations)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/692/A205/tableb?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/692/A205/tableb?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/692/A205/tableb?GETtext/xml+votable180.050000true40.2700119-8.25575890.005555555555555556Cone search capability for table J/A+A/692/A205/list (Information on fits image)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/692/A205/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/692/A205/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/692/A205/list?GETtext/xml+votable180.050000true40.26999-8.255760.005555555555555556Associated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/692/A2056/36785https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/692/A205?format=asciiRadiodefaultJ/A+A/692/A205/tablebFit parameters and uncertainties of 1.6, 5.0, 8.4, 15.3, 22.2, and 43.1GHz VLBA and 86 GHz GMVA observationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDID of componentmeta.id;meta.maincharFreqObserving Frequency (1.55, 4.98, 8.42, 15.26, 22.22, 43.12 and 86.25)GHzem.freqfloatSFreqFlux density at FreqmJyphot.flux.density;em.radiofloatoRAOffset in right ascension (1)maspos.eq.ra;arith.difffloate_oRAoRA errormasstat.errorfloatoDEOffset in declination (1)maspos.eq.dec;arith.difffloate_oDEoDE errormasstat.errorfloatMajorMajor axismasphys.angSizefloate_MajorMajor axis errormasstat.errorfloatRatio? Ratio major to minor axisphys.size.axisRatiofloatnullableDistComponent angular distancemaspos.angDistancefloate_Dist? Angular distance errormasstat.errorfloatnullablel_logTbLimit flag on logTbmeta.code.errorcharlogTbLogarithm of brightness temperaturelog(K)phys.temperaturefloat_RAComputed Right Ascension for Equinox: J2000degpos.eq.ra;meta.main_DEComputed Declination for Equinox: J2000degpos.eq.dec;meta.mainJ/A+A/692/A205/listInformation on fits imagerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension of center (J2000)degpos.eq.ra;meta.mainDEJ2000Declination of center (J2000)degpos.eq.dec;meta.mainNxNumber of pixels along X-axismeta.numberintNyNumber of pixels along Y-axismeta.numberintObs.dateObservation datestime.epoch;obsnullableFreqObserved frequencyGHzem.freqfloatsizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitscharAssocDataAssociated Data web pagemeta.ref.urlchar