J/ApJ/738/128ivo://CDS.VizieR/J/ApJ/738/128doi:10.26093/cds/vizier.17380128CDSSeifina E.Titarchuk L.2013-06-22T13:24:50Z2013-06-05T14:06:22ZCDS support team

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

cds-question@unistra.frx-ray-binary-starsline-intensitiesWe present an analysis of the spectral properties observed in X-rays from neutron star X-ray binary 4U 1728-34 during transitions between the low- and high-luminosity states when the electron temperature kT_e_ of the Compton cloud monotonically decreases from 15 to 2.5keV. We analyze the transition episodes from this source observed with BeppoSAX and RXTE satellites. We find that the X-ray broadband energy spectra of 4U 1728-34 during all spectral states can be modeled by a combination of a thermal (blackbody-like) component, a Comptonized component (which we herein denote as COMPTB), and a Gaussian component. Spectral analysis using this model provides evidence that the photon power-law index {Gamma} is almost constant ({Gamma}=1.99+/-0.02) when kT_e_ changes from 15 to 2.5keV during these spectral transitions.2011ApJ...738..128Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/738/128CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/cb : Cataclysmic Binaries, LMXBs, and related objects (Ritter+, 2013)J/A+A/545/A27 : INTEGRAL/IBIS Galactic Hard X-Ray Survey (Krivonos+, 2012)J/ApJ/714/1424 : Isolated neutron stars from Rosat and Swift (Turner+, 2010)J/A+A/523/A61 : INTEGRAL survey of hard X-ray sources (Krivonos+, 2010)J/A+A/522/A68 : Variable sources detected by INTEGRAL (Telezhinsky+, 2010)J/ApJS/179/360 : Thermonuclear X-ray bursts observed by RXTE (Galloway+, 2008)J/A+A/467/585 : Sources detected by ISGRI (Bodaghee+, 2007)J/A+A/469/807 : Catalogue of Galactic low-mass X-ray binaries (Liu+, 2007)J/A+A/458/21 : INTEGRAL burst observations of 4U 1728-34 (Falanga+, 2006)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/738/128https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/738/128http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/738/128https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/738/128https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/738/128http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/738/128GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/ApJ/738/128/table4*Best-fit parameters of the spectral analysis of PCA & HEXTE/RXTE observations of 4U 1728-34 in the 3-60keV energy rangeExpExposure timestime.duration;obs.exposureintf_logA[b] logA fixed (2)meta.codechare_EWEW uncertaintyeVstat.error;spect.line.eqWidthintchi2{chi}^2^ fitstat.fit.chi2floatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintObsIDObservational identificationmeta.id;obscharMJD[50128/51734] Start time (Modified Julian Date)dtime.epochdoubleRateCount rate, background corrected (1)ct/sphot.count;em.X-rayfloatalphaEnergy index of the Comptonization spectrum {alpha}={Gamma}-1spect.indexfloate_alphaalpha uncertaintystat.error;pos.eq.rafloatTeElectron temperaturekeVphys.temperature.electron;phys.electronfloate_TeTe uncertaintykeVstat.errorfloatlogACOMPTB parameter log(A)stat.fit.paramfloate_logA? logA uncertaintystat.errorfloatnullableNcompNormalization of the seed photon spectrum N_COMPTB_ (3)stat.fit.paramfloate_NcompNcompt uncertaintystat.errorfloatNbbNormalization of the blackbody component N_BB_ (3)stat.fit.paramfloate_NbbNbb uncertaintystat.errorfloatElineCentroid line energykeVphys.energy;spect.linefloate_ElineEline uncertaintykeVstat.errorfloatNlineNormalization N_line_ to fit the data in the 6-8keV range (3)stat.fit.paramfloate_NlineNline uncertaintystat.errorfloatEWEquivalent width of iron line EW_line_eVspect.line.eqWidthinte_chi2chi2 uncertaintystat.errorfloatF1Spectral flux for 3-10keV energy range (4)pW.m**-2phot.fluxfloatF2Spectral flux for 10-60keV energy range (4)pW.m**-2phot.fluxfloat