J/ApJS/266/37ivo://CDS.VizieR/J/ApJS/266/37doi:10.26093/cds/vizier.22660037CDSAbe H.Abe S.Acciari V.A.Agudo I.Aniello T.Ansoldi S.,Antonelli L.A.Arbet-Engels A.Arcaro C.Artero M.Asano K.Baack D.,Babic A.Baquero A.Barres de Almeida U.Barrio J.A.Batkovic I.,Baxter J.Becerra Gonzalez J.Bednarek W.Bernardini E.Bernardos M.,Berti A.Besenrieder J.Bhattacharyya W.Bigongiari C.Biland A.,Blanch O.Bonnoli G.Bosnjak Z.Burelli I.Busetto G.Carosi R.,Carretero-Castrillo M.Castro-Tirado A.J.Ceribella G.Chai Y.,Chilingarian A.Cikota S.Colombo E.Contreras J.L.Cortina J.,Covino S.D'Amico G.D'Elia V.Da Vela P.Dazzi F.De Angelis A.,De Lotto B.Del Popolo A.Delfino M.Delgado J.Delgado Mendez C.,Depaoli D.Di Pierro F.Di Venere L.Do Souto Espineira E.,Dominis Prester D.Donini A.Dorner D.Doro M.Elsaesser D.Emery G.,Escudero J.Fallah Ramazani V.Farina L.Fattorini A.Foffano L.,Font L.Fruck C.Fukami S.Fukazawa Y.Garcia Lopez R.J.,Garczarczyk M.Gasparyan S.Gaug M.Giesbrecht Paiva J.G.,Giglietto N.Giordano F.Gliwny P.Godinovic N.Grau R.Green D.,Green J.G.Hadasch D.Hahn A.Hassan T.Heckmann L.Herrera J.,Hrupec D.Hutten M.Imazawa R.Inada T.Iotov R.Ishio K.,Jimenez Martinez I.Jormanainen J.Kerszberg D.Kobayashi Y.Kubo H.,Kushida J.Lamastra A.Lelas D.Leone F.Lindfors E.Linhoff L.,Lombardi S.Longo F.Lopez-Coto R.Lopez-Moya M.Lopez-Oramas A.,Loporchio S.Lorini A.Lyard E.Machado de Oliveira Fraga B.,Majumdar P.Makariev M.Maneva G.Mang N.Manganaro M.Mangano S.,Mannheim K.Mariotti M.Martinez M.Mas-Aguilar A.Mazin D.,Menchiari S.Mender S.Micanovic S.Miceli D.Miener T.Miranda J.M.,Mirzoyan R.Molina E.Mondal H.A.Moralejo A.Morcuende D.Moreno V.,Nakamori T.Nanci C.Nava L.Neustroev V.Nievas Rosillo M.Nigro C.,Nilsson K.Nishijima K.Njoh Ekoume T.Noda K.Nozaki S.Ohtani Y.,Oka T.Okumura A.Otero-Santos J.Paiano S.Palatiello M.Paneque D.,Paoletti R.Paredes J.M.Pavletic L.Persic M.Pihet M.Pirola G.,Podobnik F.Prada Moroni P.G.Prandini E.Principe G.Priyadarshi C.,Rhode W.Ribo M.Rico J.Righi C.Rugliancich A.Sahakyan N.,Saito T.Sakurai S.Satalecka K.Saturni F.G.Schleicher B.,Schmidt K.Schmuckermaier F.Schubert J.L.Schweizer T.Sitarek J.,Sliusar V.Sobczynska D.Spolon A.Stamerra A.Striskovic J.,Strom D.Strzys M.Suda Y.Suric T.Tajima H.Takahashi M.,Takeishi R.Tavecchio F.Temnikov P.Terauchi K.Terzic T.,Teshima M.Tosti L.Truzzi S.Tutone A.Ubach S.van Scherpenberg J.,Vazquez Acosta M.Ventura S.Verguilov V.Viale I.Vigorito C.F.,Vitale V.Vovk I.Walter R.Will M.Wunderlich C.Yamamoto T.,Zaric D.,The MAGIC Collaboration,Cerruti M.Acosta-Pulido J.A.Apolonio G.Bachev R.,Balokovic M.Benitez E.Bjorklund I.Bozhilov V.Brown L.F.Bugg A.,Carbonell W.Carnerero M.I.Carosati D.Casadio C.Chamani W.,Chen W.P.Chigladze R.A.Damljanovic G.Epps K.Erkenov A.Feige M.,Finke J.Fuentes A.Gazeas K.Giroletti M.Grishina T.S.Gupta A.C.,Gurwell M.A.Heidemann E.Hiriart D.Hou W.J.Hovatta T.Ibryamov S.,Joner M.D.Jorstad S.G.Kania J.Kiehlmann S.Kimeridze G.N.,Kopatskaya E.N.Kopp M.Korte M.Kotas B.Koyama S.Kramer J.A.,Kunkel L.Kurtanidze S.O.Kurtanidze O.M.Lahteenmaki A.Lopez J.M.,Larionov V.M.Larionova E.G.Larionova L.V.Leto C.Lorey C.,Mujica R.Madejski G.M.Marchili N.Marscher A.P.Minev M.,Modaressi A.Morozova D.A.Mufakharov T.Myserlis I.Nikiforova A.A.,Nikolashvili M.G.Ovcharov E.Perri M.Raiteri C.M.Readhead A.C.S.,Reimer A.Reinhart D.Righini S.Rosenlehner K.Sadun A.C.,Savchenko S.S.Scherbantin A.Schneider L.Schoch K.Seifert D.,Semkov E.Sigua L.A.Singh C.Sola P.Sotnikova Y.Spencer M.,Steineke R.Stojanovic M.Strigachev A.Tornikoski M.Traianou E.,Tramacere A.Troitskaya Y.V.Troitskiy I.S.Trump J.B.Tsai A.,Valcheva A.Vasilyev A.A.Verrecchia F.Villata M.Vince O.,Vrontaki K.Weaver Z.R.Zaharieva E.Zottmann N.,2025-05-22T20:14:04Z2023-10-24T12:09:42ZCDS support team

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

cds-question@unistra.frbl-lacertae-objectsactive-galactic-nucleigamma-ray-astronomyx-ray-sourcesradio-sourcesphotometryvisible-astronomypolarimetryspectral-energy-distributionultraviolet-astronomyWe study the broadband emission of Mrk 501 using multiwavelength observations from 2017 to 2020 performed with a multitude of instruments, involving, among others, MAGIC, Fermi's Large Area Telescope (LAT), NuSTAR, Swift, GASP-WEBT, and the Owens Valley Radio Observatory. Mrk 501 showed an extremely low broadband activity, which may help to unravel its baseline emission. Nonetheless, significant flux variations are detected at all wave bands, with the highest occurring at X-rays and very-high-energy (VHE) {gamma}-rays. A significant correlation (>3{sigma}) between X-rays and VHE {gamma}-rays is measured, supporting leptonic scenarios to explain the variable parts of the emission, also during low activity. This is further supported when we extend our data from 2008 to 2020, and identify, for the first time, significant correlations between the Swift X-Ray Telescope and Fermi-LAT. We additionally find correlations between high-energy {gamma}-rays and radio, with the radio lagging by more than 100 days, placing the {gamma}-ray emission zone upstream of the radio-bright regions in the jet. Furthermore, Mrk 501 showed a historically low activity in X-rays and VHE {gamma}-rays from mid-2017 to mid-2019 with a stable VHE flux (>0.2TeV) of 5% the emission of the Crab Nebula. The broadband spectral energy distribution (SED) of this 2yr long low state, the potential baseline emission of Mrk 501, can be characterized with one-zone leptonic models, and with (lepto)-hadronic models fulfilling neutrino flux constraints from IceCube. We explore the time evolution of the SED toward the low state, revealing that the stable baseline emission may be ascribed to a standing shock, and the variable emission to an additional expanding or traveling shock.2023ApJS..266...37Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/266/37CatalogResearchIsServedByTAP VizieR generic servicerelated-toII/328 : AllWISE Data Release (Cutri+ 2013)VIII/76 : Leiden/Argentine/Bonn (LAB) Survey of Galactic HI (Kalberla+ 2005)J/A+AS/132/305 : Extragal. radio sources at 22, 37 and 87GHz (Terasranta+ 1998)J/AJ/134/799 : Multiwaveband polarimetry of 15 AGN (Jorstad+, 2007)J/ApJ/716/30 : SED of Fermi bright blazars (Abdo+, 2010)J/ApJ/741/30 : Radio/{gamma}-ray correlation in AGN (Ackermann+, 2011)J/ApJ/740/98 : Synchroton peak for blazars and radio galaxies (Meyer+, 2011)J/ApJS/194/29 : Observations of blazars at 15GHz (Richards+, 2011)J/ApJ/792/30 : NEOWISE magnitudes for near-Earth objects (Mainzer+, 2014)J/A+A/573/A50 : Multiwavelength obs. of Mrk 501 in 2008 (Aleksic+, 2015)J/A+A/576/A126 : The 2009 multiwavelength campaign on Mrk421 (Aleksic+, 2015)J/A+A/596/A78 : R-band polarization curves of 48 BL Lacs (Hovatta+, 2016)J/ApJ/846/98 : Jet kinematics of blazars at 43GHz with VLBA (Jorstad+, 2017)J/AN/338/700 : Flux densities for 290 blazars (Mingaliev+, 2017)J/ApJ/864/84 : Swift follow-up obs. of TXS 0506+056 blazar (Keivani+, 2018)J/ApJS/247/33 : The Fermi LAT fourth source catalog (4FGL) (Abdollahi+, 2020)J/ApJS/247/16 : Extreme high-frequency-peaked BL Lac objects (Acciari+, 2020)J/A+A/655/A93 : Mrk 501 long-term multi-band photometry (Arbet-Engels+, 2021)J/ApJ/923/30 : MOJAVE. XVIII. Bright radio-loud active AGNs (Lister+, 2021)J/ApJS/260/12 : Jet kinematics of blazars at 43GHz (Weaver+, 2022)http://www.oato.inaf.it/blazars/webt/ : Whole Earth Blazar Telescope home pagehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/266/37https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/266/37http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/266/37https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/266/37https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/266/37http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/266/37GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapGamma-rayX-rayUVOpticalRadiodefaultJ/ApJS/266/37/vheAll published very-high-energy (VHE; E>0.1TeV) data (Data behind Figure 1)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJD[53518.9/59082.91] Modified Julian Datedtime.epochdoubleFlux[-0.11/6.51] Flux in Crab unitsphot.flux.density;em.gamma.harddoublee_Flux[0/0.6] Flux uncertainty (Crab units)stat.error;phot.fluxdoublel_EnergyUpper limit flag on Energymeta.code.error;phys.energycharEnergyEnergy threshold of each analysis (2)TeVem.energyfloatRefReference to the publication the data is taken from (3)meta.bibcharDOIDOI of the referencemeta.bibcharInstInstrument (1)meta.id;instrcharJ/ApJS/266/37/xrtSwift-XRT data (Data behind Figure 1)recnoRecord number assigned by the VizieR team. 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Should Not be used for identification.meta.recordintMJD[57834.2/59082.91] Modified Julian Datedtime.epochdoubleFlux[-1.6e-12/6e-11] Flux in ph/cm^2^/sph.cm**-2.s**-1phot.flux.density;em.gamma.harddoublee_Flux[1e-12/8.2e-12] Flux uncertaintyph.cm**-2.s**-1stat.error;phot.fluxdoubleLimit[6.8e-12/4.2e-11]? Upper limit in flux (1)phot.flux;em.gamma;stat.maxdoublenullableInstInstrument (either nightly binned or weekly binned)meta.id;instrcharBandBand (always >0.2 TeV)instr.bandpasscharBin[0.006/3.5] The MJD bin sizespect.binSizedoubleJ/ApJS/266/37/lat2Fermi-LAT data in 14 day bins (data behind Figure 2)recnoRecord number assigned by the VizieR team. 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Should Not be used for identification.meta.recordintMJD[53481/59112.9] Modified Julian Datedtime.epochdoubleFlux[4.7e-12/4.9e-10] Flux in erg/cm^2^/smW.m**-2phot.flux;em.X-raydoublee_Flux[1e-13/2e-11] Lower uncertainty in FluxmW.m**-2stat.error;phot.fluxdoubleE_Flux[1e-13/3e-11] Upper uncertainty in FluxmW.m**-2stat.error;stat.maxdoubleBandX-ray range (0.3-2, 2-10, 3-7 or 7-30)keVinstr.bandpasscharInstThe instrument ("Swift-XRT" or "NuSTAR")instrcharJ/ApJS/266/37/uvotSwift-UVOT data (data behind Figure 2)recnoRecord number assigned by the VizieR team. 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Should Not be used for identification.meta.recordintEnergy[6.2e-05/1.7e+12] Center energyeVphys.energydoubleb_EnergyMinimum energyeVphys.energy;stat.mindoubleB_EnergyMaximum energyeVphys.energy;stat.maxdoubleE2dNdE[1.5e-13/4.3e-11] Center flux density in erg/cm^2^/s unitsmW.m**-2phot.flux.densitydoubleb_E2dNdEMinimum flux densitymW.m**-2phot.flux.density;stat.mindoubleB_E2dNdEMaximum flux densitymW.m**-2phot.flux.density;stat.maxdoubleLabelLegend label (including instrument name)meta.id;instrcharJ/ApJS/266/37/fig9b*Broadband SED around the first NuSTAR observation (NuSTAR-1) on 2017-04-28 (MJD57871)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintEnergy[6.2e-05/1.7e+12] Center energyeVphys.energydoubleb_EnergyMinimum energyeVphys.energy;stat.mindoubleB_EnergyMaximum energyeVphys.energy;stat.maxdoubleE2dNdE[1.5e-13/4.3e-11] Center flux density in erg/cm^2^/s unitsmW.m**-2phot.flux.densitydoubleb_E2dNdEMinimum flux densitymW.m**-2phot.flux.density;stat.mindoubleB_E2dNdEMaximum flux densitymW.m**-2phot.flux.density;stat.maxdoubleLabelLegend label (including instrument name)meta.id;instrcharJ/ApJS/266/37/fig9c*Broadband SED around the the second NuSTAR observation (NuSTAR-2) on 2017-05-25 (MJD57898)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintEnergy[6.2e-05/1.7e+12] Center energyeVphys.energydoubleb_EnergyMinimum energyeVphys.energy;stat.mindoubleB_EnergyMaximum energyeVphys.energy;stat.maxdoubleE2dNdE[1.5e-13/4.3e-11] Center flux density in erg/cm^2^/s unitsmW.m**-2phot.flux.densitydoubleb_E2dNdEMinimum flux densitymW.m**-2phot.flux.density;stat.mindoubleB_E2dNdEMaximum flux densitymW.m**-2phot.flux.density;stat.maxdoubleLabelLegend label (including instrument name)meta.id;instrchar