J/A+A/690/A344ivo://CDS.VizieR/J/A+A/690/A344doi:10.26093/cds/vizier.36900344CDSMessa M.M.D'Avanzo P.Coti Zelati F.Baglio M.C.Campana S.2025-02-12T20:01:15Z2024-10-22T10:53:39ZCDS support team

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

cds-question@unistra.frx-ray-binary-starsvisible-astronomyspectroscopyTransitional millisecond pulsars (tMSPs) represent a dynamic category of celestial sources that establish a crucial connection between low-mass X-ray binaries and millisecond radio pulsars. These systems exhibit transitions from rotation-powered states to accretion-powered ones and vice versa, highlighting the tight evolutionary link expected by the so-called recycling scenario. In their active phase, these sources manifest two distinct emission modes named high and low, occasionally punctuated by sporadic flares. Here, we present high-time-resolution spectroscopic observations of the binary tMSP J1023+0038, in the sub-luminous disc state. This is the first short-timescale (~1 min) optical spectroscopic campaign ever conducted on a tMSP. The campaign was carried out over the night of June 10, 2021 using the Gran Telescopio Canarias. The optical continuum shows erratic variability, without clear evidence of high and low modes or of orbital modulation. Besides, the analysis of these high-temporal-cadence spectroscopic observations reveals, for the first time, evidence for a significant (up to a factor of ~2) variability in the emission line properties (equivalent width and full width half maximum) over a timescale of minutes. Intriguingly, the variability episodes observed in the optical continuum and in the emission line properties seem uncorrelated, making their origin unclear.2024A&A...690A.344Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/690/A344CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/591/A101 : PSRJ1023+0038 + XSSJ12270-4859 VRi polarimetry (Baglio+ 2016)J/A+A/631/A104 : PSRJ1023+0038 VLT, XM and Swift observations (Baglio+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/690/A344https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/690/A344http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/690/A344https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/690/A344https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/690/A344http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/690/A344GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapX-rayOpticaldefaultJ/A+A/690/A344/logInformation on the 87 reduced spectrarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDNumber of the spectrummeta.id;meta.mainintTel[GTC] Name of the telescopemeta.id;instr.telcharInst[OSIRIS] Name of the instrumentmeta.id;instrcharMJDstartStarting date of the spectra (MJD)dtime.epochdoubleTexp[20] Exposure time of the single spectrumstime.duration;obs.exposureintspShow the spectrummeta.ref.urlcharFileNameName of the spectrum file in subdirectory spmeta.id;meta.filechar