J/ApJ/932/66ivo://CDS.VizieR/J/ApJ/932/66doi:10.26093/cds/vizier/ba-x4-22CDSRen X.Q.Wang Y.Zhang S.N.Soria R.Tao L.Ji L.Yang Y.J.,Qu J.L.Zhang S.Song L.M.Ge M.Y.Huang Y.Li X.B.Liao J.Y.,Liu H.X.Ma R.C.Tuo Y.L.Wang P.J.Zhang W.Zhou D.K.2026-02-20T20:01:47Z2025-04-16T11:32:18ZCDS support team

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

cds-question@unistra.frx-ray-sourcesblack-holesx-ray-binary-starsWe study the spectral evolution of the black hole candidate EXO1846-031 during its 2019 outburst, in the 1-150keV band, with the Hard X-ray Modulation Telescope. The continuum spectrum is well modeled with an absorbed disk-blackbody plus cutoff power law, in the hard, intermediate, and soft states. In addition, we detect an ~6.6keV Fe emission line in the hard intermediate state. Throughout the soft intermediate and soft states, the fitted inner disk radius remains almost constant; we suggest that it has settled at the innermost stable circular orbit (ISCO). However, in the hard and hard intermediate states, the apparent inner radius was unphysically small (smaller than the ISCO), even after accounting for the Compton scattering of some of the disk photons by the corona in the fit. We argue that this is the result of a high hardening factor, f_col_~2.0-2.7, in the early phases of the outburst evolution, well above the canonical value of 1.7 suitable for a steady disk. We suggest that the inner disk radius was already close to the ISCO in the low/hard state. Furthermore, we propose that this high value of the hardening factor in the relatively hard state was probably caused by the additional illuminating of the coronal irradiation onto the disk. Additionally, we estimate the spin parameter using the continuum-fitting method, over a range of plausible black hole masses and distances. We compare our results with the spin measured using the reflection-fitting method and find that the inconsistency of the two results is partly caused by different choices of fcol.2022ApJ...932...66Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/932/66CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/MNRAS/415/292 : MAXI J1659-152 2010 outburst analysis (Munoz-Darias+, 2011)J/A+A/587/A61 : BlackCAT, stellar-mass BH in X-ray (Corral-Santana+, 2016)J/ApJ/822/60 : RXTE observations of GRS 1915+105 (Peris+, 2016)J/ApJS/222/15 : WATCHDOG: all-sky database of Gal. BHXBs (Tetarenko+, 2016)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/932/66https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/932/66http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/932/66https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/932/66https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/932/66http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/932/66GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapX-raydefaultJ/ApJ/932/66/table1Insight-HXMT observations of EXO 1846-031ExpIDExposure identifier (1)meta.id;obs.exposureintprimaryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTimeStart time; YYYY-MM-DDThh:mm:ss.ssstime.epoch;time.startnullableMJD[58697.35/58781.57] Modified Julian Date of start timedtime.epoch;time.startdoubleHE[1.37/263.6] High energy, 25-150keV, count ratect/sphot.count;em.X-ray.hardfloate_HE[0.02/0.6] Uncertainty in HEct/sstat.error;phot.count;em.X-ray.hardfloatME[0.9/52] Medium energy, 10-20keV, count ratect/sarith.rate;phot.count;em.X-ray.mediumfloate_ME[0.02/0.5] Uncertainty in MEct/sstat.error;phot.count;em.X-ray.mediumfloatLE[67.8/220.5] Low energy, 1-10keV, count ratect/sarith.rate;phot.count;em.X-ray.mediumfloate_LE[0.2/1] Uncertainty in LEct/sstat.error;phot.count;em.X-ray.mediumfloatHEExp[264/4988] High energy band exposure timestime;obs.exposure;em.X-ray.hardintMEExp[287/3967] Medium energy band exposure timestime;obs.exposure;em.X-ray.mediumintLEExp[239/2858] Low energy band exposure timestime;obs.exposure;em.X-ray.mediumintStateSource state (2)meta.code.classcharJ/ApJ/932/66/table2Spectral fitting results of EXO 1846-031 using TBabs*(cutoffpl+diskbb) model, N_H_ fixed at 5.34e+22cm^-2^ExpID[101/4903] Exposure identifiermeta.id;obs.exposureintprimaryfdbb[0.05/1] Disk flux fractionphot.flux;arith.ratiofloatE_fdbb[0.005/0.1] Upper uncertainty in fdbbstat.error;stat.max;phot.fluxfloate_fdbb[0.005/0.06] Lower uncertainty in fdbbstat.error;stat.min;phot.fluxfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintModelModel identifier (G1)meta.id;meta.modelledcharGamma[1.39/3] Photon indexmeta.code;spect.index;meta.modelledfloatE_Gamma[0.03/0.7] Upper uncertainty in Gammastat.error;stat.max;spect.indexfloate_Gamma[0.04/0.6] Lower uncertainty in Gammastat.error;stat.min;spect.indexfloatEcut[40/500] Energy cutoffkeVem.energy;em.X-rayintf_Ecut[f] Flag on Ecut (G2)meta.code;em.energycharE_Ecut[3/200]? Upper uncertainty in EcutkeVstat.error;stat.max;em.energyintnullablen_Ecut[p] Ecut is pagged at its upper limitmeta.note;em.energychare_Ecut[3/300]? Lower uncertainty in EcutkeVstat.error;stat.min;em.energyintnullablekTin[0.78/1.8] Color temperaturekeVphys.temperature;em.X-rayfloatE_kTin[0.003/0.3] Upper uncertainty in kTinkeVstat.error;stat.max;phys.temperaturefloate_kTin[0.003/0.3] Lower uncertainty in kTinkeVstat.error;stat.min;phys.temperaturefloatNdbb[4/1300] Diskbb normalizationarith.factorintE_Ndbb[2/80] Upper uncertainty in Ndbbstat.error;stat.maxinte_Ndbb[2/80] Lower uncertainty in Ndbbstat.error;stat.minintEgau[6.4/7]? Central energy of gaussian modelkeVem.energy;em.X-rayfloatnullableE_Egau[0.1/0.4]? Upper uncertainty in EgaukeVstat.error;stat.max;em.energyfloatnullablee_Egau[0.1/0.4]? Lower uncertainty in EgaukeVstat.error;stat.min;em.energyfloatnullablen_Egau[p] Egau is pagged at its lower limitmeta.note;em.energycharsigma[0.4/1.6]? Line width of gaussian modelkeVspect.line.width;meta.modelledfloatnullableE_sigma[0.1/0.7]? Upper uncertainty in sigmakeVstat.error;stat.max;spect.line.widthfloatnullablee_sigma[0.2/0.6]? Lower uncertainty in sigmakeVstat.error;stat.min;spect.line.widthfloatnullablen_sigma[u] Indicates sigma is unconstrainedmeta.note;spect.line.widthcharchi2/dofModel {chi}^2^/degrees of freedomstat.fit.chi2charFdbb[0.04/2.1] Disk component flux (G3)1e-08mW.m**-2phot.flux;em.X-rayfloatE_Fdbb[0.006/0.1] Upper uncertainty in Fdbb1e-08mW.m**-2stat.error;stat.max;phot.fluxfloate_Fdbb[0.006/0.1] Lower uncertainty in Fdbb1e-08mW.m**-2stat.error;stat.min;phot.fluxfloatFpl[0.03/1.3] Power-law component flux (G3)1e-08mW.m**-2phot.flux;em.X-ray;meta.modelledfloatE_Fpl[0.005/0.5] Uncertainty in Fpl1e-08mW.m**-2stat.error;stat.max;phot.fluxfloate_Fpl[0.005/0.2] Uncertainty in Fpl1e-08mW.m**-2stat.error;stat.min;phot.fluxfloatJ/ApJ/932/66/table3Spectral fitting results of EXO 1846-031 using TBabs*(simplcut+diskbb) model, N_H_ fixed at 5.25e+22cm^-2^ExpID[101/4903] Exposure identifiermeta.id;obs.exposureintprimaryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintModelModel identifier (G1)meta.id;meta.modelledcharGamma[1.4/3] Photon indexmeta.code;spect.index;meta.modelledfloatE_Gamma[0.02/0.6] Upper uncertainty in Gammastat.error;stat.max;spect.indexfloate_Gamma[0.02/0.7] Lower uncertainty in Gammastat.error;stat.min;spect.indexfloatEcut[50/500] Energy cutoffkeVem.energy;em.X-rayintf_Ecut[f] Flag on Ecut (G2)meta.code;em.energycharE_Ecut[3/190]? Upper uncertainty in EcutkeVstat.error;stat.max;em.energyintnullablen_Ecut[p] Ecut is pagged at its upper limitmeta.note;em.energychare_Ecut[3/300]? Lower uncertainty in EcutkeVstat.error;stat.min;em.energyintnullablekTin[0.67/1.2] Color temperaturekeVphys.temperature;em.X-rayfloatE_kTin[0.003/0.2] Upper uncertainty in kTinkeVstat.error;stat.max;phys.temperaturefloate_kTin[0.003/0.3] Lower uncertainty in kTinkeVstat.error;stat.min;phys.temperaturefloatNdbb[150/1400] Diskbb normalizationarith.factorintE_Ndbb[17/600] Upper uncertainty in Ndbbstat.error;stat.maxinte_Ndbb[16/300] Lower uncertainty in Ndbbstat.error;stat.minintfsc[0.003/1] Scattered fractionstat.fit.paramfloatE_fsc[0.001/0.11] Upper uncertainty in fscstat.error;stat.maxfloate_fsc[0.001/0.12] Lower uncertainty in fscstat.errorfloatEgau[6.4/6.8]? Central energy of gaussian modelkeVem.energy;em.X-rayfloatnullableE_Egau[0.1/0.4]? Upper uncertainty in EgaukeVstat.error;stat.max;em.energyfloatnullablee_Egau[0.1/0.4]? Lower uncertainty in EgaukeVstat.error;stat.min;em.energyfloatnullablen_Egau[p] Egau is pagged at its lower limitmeta.note;em.energycharsigma[0.1/1.6]? Line width of gaussian modelkeVspect.line.width;meta.modelledfloatnullableE_sigma[0.1/4.2]? Upper uncertainty in sigmakeVstat.error;stat.max;spect.line.widthfloatnullablee_sigma[0.1/0.6]? Lower uncertainty in sigmakeVstat.error;stat.min;spect.line.widthfloatnullablechi2/dofModel {chi}^2^/degrees of freedomstat.fit.chi2charFdbb[0.2/2.3] Disk component flux (G3)1e-08mW.m**-2phot.flux;em.X-rayfloatE_Fdbb[0.007/0.12] Upper uncertainty in Fdbb1e-08mW.m**-2stat.error;stat.max;phot.fluxfloate_Fdbb[0.007/0.1] Lower uncertainty in Fdbb1e-08mW.m**-2stat.error;stat.min;phot.fluxfloatFpl[0.01/1.4] Power-law component flux (G3)1e-08mW.m**-2phot.flux;em.X-ray;meta.modelledfloatE_Fpl[0.02/0.12] Uncertainty in Fpl1e-08mW.m**-2stat.error;stat.max;phot.fluxfloate_Fpl[0.02/0.11] Uncertainty in Fpl1e-08mW.m**-2stat.error;stat.min;phot.fluxfloatfdbb[0.16/0.992] Disk flux fractionphot.flux;arith.ratiofloatE_fdbb[0.007/0.07] Upper uncertainty in fdbbstat.error;stat.max;phot.fluxfloate_fdbb[0.008/0.05] Lower uncertainty in fdbbstat.error;stat.min;phot.fluxfloat