J/A+A/711/A60ivo://CDS.VizieR/J/A+A/711/A60CDSin 't Zand J.J.M.Guidorzi C.Heise J.Amati L.Kuulkers E.,Frontera F.Gianfanga G.Piro L.2026-07-06T07:23:24Z2026-07-06T08:20:29ZCDS support team

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

cds-question@unistra.frgamma-ray-astronomygamma-ray-burstsx-ray-binary-starsWe performed a search for fast X-ray transients (FXTs), defined for the purposes of this work as transients with durations of longer than one second and shorter than one day. We used data from the Wide Field Camera (WFC) instrument on board the BeppoSAX X-ray observatory collected between June 1996 and April 2002. The WFC sensitivity ranged from 10^-9^erg/s/cm^2^ (2-10keV), for a timescale of 10s, to a few times 10^-11^erg/s/cm^2^,, for a timescale of 10^5^s. The WFC location accuracy was 0.7-4.9 arcmin at a 68% confidence. We focused our search on gamma-ray bursts (GRBs), X-ray flashes (XRFs), and X-ray flares from high-mass X-ray binaries and stellar flares. Overall, 149 FXTs were detected. 63 of these are new to the literature. 38 flares were identified with 22 nearby stars. Three stars in the sample have never been seen flaring before in X-rays or optical (NLTT 51688, GR Dra and UCAC4 255-003783). We find that the MeV transient GRO J1753+57 is most likely the same object as GR Dra, rather than an active galactic nucleus (AGN) as previously thought. Eleven flares were detected from known high-mass X-ray binaries with irregular wind accretion. 100 GRBs were identified. Of these, 24 had not been published before. We classified 38% of the X-ray detected GRBs as XRFs with a relatively high X-ray-to-gamma-ray flux ratio. The gamma rays were measured with the BeppoSAX Gamma Ray Burst Monitor. The duration and spectral hardness distribution of all FXTs are bimodal, separating the group roughly in transients that are either shorter or longer than 1 ksec and with relatively hard and soft spectra, respectively. We identified the "short" FXTs as GRBs and XRFs and the "long" FXTs as flares from nearby late-type stars and X-ray binaries. The BeppoSAX-WFC FXT sample is found to be consistent with the one observed by Einstein Probe when the sensitivity of the two instruments is taken into account. These results suggest that the bulk of the population of faints events disclosed by Einstein Probe could represent the extension of a similar population to lower luminosities.2026A&A...711A..60Ihttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/711/A60CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/711/A60https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/711/A60http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/711/A60https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/711/A60https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/711/A60http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/711/A60GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/711/A60/tablea2 (Catalog of 149 FXTs detected with BeppoSAX-WFC)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/711/A60/tablea2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/711/A60/tablea2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/711/A60/tablea2?GETtext/xml+votable180.050000true341.719644.32960.0055555555555555566/845 1698 1704 3023 3025 3310 3925 4733 6141 6618 6729 6959 7241 7302 7650 7766 7877 8059 8103 8447 8603 9531 9686 9691 9703 9910 10194 10589 10790 11219 11388 11574 12058 12060 12079 12239 13516 13743 13947 14245 15243 15281 15464 16212 16276 16303 16308 16461 16919 17742 17812 18844 20071 20102 20286 22052 22109 23413 23812 23899 25148 26242 26833 28151 28798 28875 29113 29528 30235 30675 32945 33015 33040 33050 33116 33287 33417 33729 34139 34266 34502 34822 34851 35150 35227 36481 36867 36880 37041 37123 37207 37318 37383 37404 37429 37513 37625 37736 37901 38020 38359 38685 39181 39194 39238 40560 40960 40988 41063 41095 41209 41243 41353 41638 41642 43272 43450 45069 45081 45347 45469 45474 45619 45722 47217 47623 48263 48786https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/711/A60?format=asciiGamma-rayX-raydefaultJ/A+A/711/A60/tablea1*Spectral fits with a power lawrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDIdentification of FXTmeta.id;meta.maincharOPBeppoSAX Observation Periodmeta.code;obsintWFCWFC camera unit numbermeta.id;instrintMJDstartStart of event in MJD(UTC)dtime.startdoubleTimeSpanTime span of extracted spectrumstime.intervalintNHGalactic hydrogen column density fixed in spectral modeling1e+20cm**-2phys.columnDensity;pos.galacticfloatPIPhoton index of model spectrumspect.indexfloate_PIUncertainty in photon index of model spectrumstat.errorfloatFL2-30keV fluence of event (in 10^-6^erg/cm^2^)1e-13W.cm**-2phot.fluence;em.gamma.hardfloate_FLUncertainty in fluence (1sigma) (in 10^-6^erg/cm^2^)1e-13W.cm**-2stat.errorfloatChi2rReduced chi-squared of fitted modelstat.fit.chi2floatDist? Distance of galactic counterparts, extracted from Simbad per GAIA parallaxespcpos.distancefloatnullablel_zLimit flag on zmeta.code.error;src.redshiftcharz? Cosmological redshift of extra-galactic counterparts if measured, extracted from Simbadsrc.redshiftfloatnullablel_EnergyLimit flag on Energymeta.code.error;phys.energycharEnergy? Total energy output in 2-30 keV (in erg unit)1e-07Wem.energydoublenullableIdentName of counterpart plus index of flare if multiple flares were observedspect.indexcharComCommentsmeta.notecharJ/A+A/711/A60/tablea2Catalog of 149 FXTs detected with BeppoSAX-WFCrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDIdentification of FXTmeta.id;meta.maincharRefReference, in refs.dat filemeta.ref;pos.frame;meta.filecharr[+x] Label (1)meta.codecharOPBeppoSAX Observation Periodmeta.code;obsintWFCWFC camera unit number (1 or 2)meta.id;instrintMJDstartStart of event in MJD(UTC)dtime.startdoubleT902-30keV T90 durationstime.durationdoublee_T90Uncertainty in T90 (1sigma)sstat.errorfloatRAJ2000Right ascension (J2000.0)degpos.eq.ra;meta.mainDEJ2000Declination (J2000.0)degpos.eq.dec;meta.mainePos? Positional uncertaintyarcminstat.error;posfloatnullableDev? Deviation from optical, X-ray or radio counterpart, if presentarcminstat.stdevfloatnullableBATSECGRO-BATSE event identification, if anymeta.idcharPeakFluxWFCWFC-measured peak fluxcount.s**-1.cm**-2phot.flux.density;em.gamma.hardfloatl_PeakFluxGRBMLimt flag on PeakFluxGRBMmeta.code.errorcharPeakFluxGRBM? GRBM-measured peak flux, if coveredct/sphot.flux.density;em.gamma.hardintnullablel_SoftnessRatioLimit flag on SoftnessRatiometa.code.errorcharSoftnessRatio? WFC peak flux divided by GRBM peak flux times 1000, if both are measuredphot.flux;arith.ratiofloatnullableType(presumed) type of sourcemeta.code.classcharIdName of counterpart plus index of flare if multiple flares were observed, if anymeta.idcharComCommentsmeta.notecharJ/A+A/711/A60/refsReferencesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRefReference codemeta.notecharBibCodeBibcodemeta.bib.bibcodecharAutAuthor's namemeta.bib.authorcharComCommentsmeta.notechar