J/ApJS/245/19ivo://CDS.VizieR/J/ApJS/245/19doi:10.26093/cds/vizier.22450019CDSBilous A.V.Watts A.L.2020-09-01T07:16:21Z2020-06-04T15:21:07ZCDS support team

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

cds-question@unistra.frx-ray-binary-starsx-ray-sourcesneutron-starsWe describe a blind uniform search for thermonuclear burst oscillations (TBOs) in the majority of Type I bursts observed by the Rossi X-ray Timing Explorer (RXTE) (2118 bursts from 57 neutron stars). We examined 2-2002Hz power spectra from the Fourier transform in sliding 0.5-2s windows, using fine-binned light curves in the 2-60keV energy range. The significance of the oscillation candidates was assessed by simulations which took into account light-curve variations, dead time, and the sliding time windows. Some of our sources exhibited multi-frequency variability at <~15Hz that cannot be readily removed with light-curve modeling and may have an astrophysical (non-TBO) nature. Overall, we found that the number and strength of potential candidates depends strongly on the parameters of the search. We found candidates from all previously known RXTE TBO sources, with pulsations that had been detected at similar frequencies in multiple independent time windows, and discovered TBOs from SAXJ1810.8-2658. We could not confirm most previously reported tentative TBO detections or identify any obvious candidates just below the detection threshold at similar frequencies in multiple bursts. We computed fractional amplitudes of all TBO candidates and placed upper limits on non-detections. Finally, for a few sources we noted a small excess of candidates with powers comparable to fainter TBOs, but appearing in single independent time windows at random frequencies. At least some of these candidates may be noise spikes that appear interesting due to selection effects. The potential presence of such candidates calls for extra caution if claiming single-window TBO detections.2019ApJS..245...19Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/245/19CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/376/161 : X-ray spectra of bursting neutron stars (Madej, 1991)J/AcA/41/73 : X-ray bursting neutron star atmosphere models (Madej, 1991)J/ApJS/179/360 : Thermonuclear X-ray bursts observed by RXTE (Galloway+, 2008)J/A+A/545/A120 : X-ray bursting neutron star atm. models II (Suleimanov+, 2012)J/ApJ/738/128 : RXTE observations of 4U 1728-34 (Seifina+, 2011)J/ApJ/747/77 : Thermonuclear X-ray bursts. II. Eddington limit (Guver+, 2012)J/A+A/581/A83 : Metal enriched X-ray bursting neutron stars. (Nattila+, 2015)J/A+A/606/A130 : List of 1254 X-ray bursts (in't+, 2017)http://burst.sci.monash.edu/minbar/ : Multi-INstrument Burst ARchive (MINBAR)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/245/19https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/245/19http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/245/19https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/245/19https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/245/19http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/245/19GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJS/245/19/sources (Overview of sources (excerpt from Table 3))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/245/19/sources?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/245/19/sources?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/245/19/sources?GETtext/xml+votable180.050000true78.5274583-40.04361110.0055555555555555566/12405 13875 23652 28690 28701 28705 28707 28751 28808 28817 28825 28827 28828 28830 28835 28849 28853 28860 28862 28880 28896 28899 28905 28916 28921 28950 28971 29100 29188 29192 29195 29267 29463 29923 30299 30439 34242 37475 37732 39247 41530 41697 41802 42140 42159 42315 42370 42384 42387 42841 47866 49023https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJS/245/19?format=asciiX-raydefaultJ/ApJS/245/19/sourcesOverview of sources (excerpt from Table 3)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDX-ray source identifiermeta.id;meta.maincharprimaryNb[1/368] Total number of bursts suitable for TBO searchmeta.numberintNburstsNumber of bursts for this source (link to Table 4)meta.numberintnullableDur[10/20954] Total burst durationstime.durationfloatSNpk[6.4/1406.4] Median SN_peak_ (1)stat.snrfloatB_FAup1s[2/81] Minimum upper limit on fractional amplitude in 1s Fourier windows on a burst peaksrc.var.amplitude;stat.maxintFAup1s[2/81] Median upper limit on fractional amplitude in 1s Fourier windows on a burst peakphot.mag;arith.ratiointChi2[0.02/34] {chi}^2^ value (2)stat.fit.chi2floatSimul[0.02/33] Number of spurious candidates in simulated data (3)meta.numberfloatReal[0/39] Number of spurious candidates in real datameta.numberintp[0/1] Percentile of the real-data number of noise candidates with respect to a 100-run simulation samplestat.fit.paramfloatSimbadSimbad column added by the CDSmeta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/ApJS/245/19/table2Data and upper limit on fractional amplitudes (FA_up_) for the burstsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDX-ray source identifiermeta.id.parentcharBNum[2203/8289] MINBAR database burst entry numbermeta.id;meta.mainintTOAMINBAR database burst time of arrival (UT date)stime.epochnullableTpeak[66413835/567575947] Burst peak in Mission Elapsed Timestime.epochdoubleRise[-50/0] Size of the rise windowsphys.angSizefloatHalfMax[0.5/274.5] Burst half-peak with respect to Burst Peaktime.epochfloatTail[1.5/814] Burst end with respect to Burst Peaktime.epochfloatS/N[2.9/1607.7] Burst peak Signal-to-Noise ratiostat.snr;stat.maxfloatModeMode of data file(s) analyzed (semi-colon separated)meta.id;meta.filecharNoteAdditional notesmeta.notecharMaxPow[19.7/352.3] Maximum Leahy-normalized power in the frequency range of 10-2002Hzem.freq;stat.maxfloatFreq[10.5/2001] Frequency of MaxPowHzem.freqfloatTwin[0.5/4] Size of FFT window with maximum powerphys.angSize;stat.maxfloatFA0.5[3.2/170.4] Best upper limit on fractional amplitude in 0.5s FFT windowsphot.mag;arith.ratiofloatFA1.0[2.4/151] Best upper limit on fractional amplitude in 1.0s FFT windowsphot.mag;arith.ratiofloatFA2.0[1.8/128.3] Best upper limit on fractional amplitude in 2.0s FFT windowsphot.mag;arith.ratiofloatFA4.0[1.3/101.1] Best upper limit on fractional amplitude in 4.0s FFT windowsphot.mag;arith.ratiofloatJ/ApJS/245/19/table4Fractional amplitudes of candidates per burstrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDX-ray source identifiermeta.id.parentcharBNum[2205/8267] MINBAR database burst entry numbermeta.id;meta.mainintTOAMINBAR database burst time of arrival (UT date)stime.epochnullableFreqFrequency or frequency rangeHzem.freqcharWhereRegion of occurrence (R=rise; B=burst or T=tail)meta.codecharNAny[1/33] Number of detections in independent time windows of any sizemeta.numberintN0.5[0/8] Number of detections in 0.5s independent time windowsmeta.numberintN1.0[0/30] Number of detections in 1.0s independent time windowsmeta.numberintN2.0[0/26] Number of detections in 2.0s independent time windowsmeta.numberintN4.0[0/17] Number of detections in 4.0s independent time windowsmeta.numberintFA0.5[5.1/680]? Maximum fractional amplitude in 0.5s time windowphot.mag;arith.ratiofloatnullablee_FA0.5[0.7/230]? Lower relative uncertainty in FA0.5stat.errorfloatnullableE_FA0.5[0.8/1204]? Upper relative uncertainty in FA0.5stat.error;stat.maxfloatnullableFA1.0[4/318]? Maximum fractional amplitude in 1.0s time windowphot.mag;arith.ratiofloatnullablee_FA1.0[0.5/178]? Lower relative uncertainty in FA1.0stat.errorfloatnullableE_FA1.0[0.5/498]? Upper relative uncertainty in FA1.0stat.error;stat.maxfloatnullableFA2.0[2.4/123]? Maximum fractional amplitude in 2.0s time windowphot.mag;arith.ratiofloatnullablee_FA2.0[0.3/39]? Lower relative uncertainty in FA2.0stat.errorfloatnullableE_FA2.0[0/41]? Upper relative uncertainty in FA2.0stat.error;stat.maxfloatnullableFA4.0[2.3/99]? Maximum fractional amplitude in 4.0s time windowphot.mag;arith.ratiofloatnullablee_FA4.0[0/28]? Lower relative uncertainty in FA4.0stat.errorfloatnullableE_FA4.0[0.3/29]? Upper relative uncertainty in FA4.0stat.error;stat.maxfloatnullable