J/A+A/696/A172ivo://CDS.VizieR/J/A+A/696/A172CDSKarl M.Padovani P.Giommi P.2026-06-12T06:00:58Z2026-06-12T06:59:20ZCDS support team

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

cds-question@unistra.frgamma-ray-astronomyThe IceCube Neutrino Observatory publishes "alert events", which are detections of high-energy neutrinos with a moderate-to-high probability of being of astrophysical origin. While some events are produced in the atmosphere, a fraction of alert events should point back to their astrophysical sources. We aim to identify multiple alert events possibly related to a single astrophysical counterpart by searching for spatial and temporal clusterings in 13 years of alert data. We identify spatial clusters ("multiplets") by checking for events overlapping within their uncertainty regions. In order to reduce chance coincidences and to improve the signal purity of our sample, we apply different thresholds. We investigate the weighted mean position of these multiplets for an over-fluctuation of gamma-ray counterparts. As a final step, we apply expectation maximization to search for temporal clusters around the identified weighted mean positions. We find no statistically significant clustering of alert events around a specific origin direction or in time. This could be because the selections are still dominated by atmospheric background. Another possibility is that we are not yet sensitive enough and only detect single events from sources. In this case, we need more data in order to observe a clustering of events around their origin.2025A&A...696A.172Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/696/A172CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/696/A172https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/696/A172http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/696/A172https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/696/A172https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/696/A172http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/696/A172GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/696/A172/tablea1 (List of alert multiplets for different areas)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/696/A172/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/696/A172/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/696/A172/tablea1?GETtext/xml+votable180.050000true336.81.530.005555555555555556Cone search capability for table J/A+A/696/A172/tablea2 (List of alert multiplets for different energy thresholds)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/696/A172/tablea2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/696/A172/tablea2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/696/A172/tablea2?GETtext/xml+votable180.050000true270.18-8.420.005555555555555556Cone search capability for table J/A+A/696/A172/tablea3 (List of alert multiplets for different signalness thresholds)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/696/A172/tablea3?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/696/A172/tablea3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/696/A172/tablea3?GETtext/xml+votable180.050000true7.6774.140.0055555555555555566/22 151 183-184 224 428 434 779 783 1050 1188 1500 3832 3991 4026 4070 4283 4286 4346 4651 4717 4801 4833 4923 5040 5088 5192 5199 5233 5509 5629 5906 5923 5972 6031 6262 7064 8253 8385 8469 8552 8894 9068 9466 9825 10304 10581 11267 11318 11351 12351 12429 12446 12471 12491 12669 12787 12882-12883 12892 13135 13161 13363 17829 17838 17847 17850 18060 18063 18079 18133 18152 18171 18248 18272 18276 18278 18298 18316 18796 18808 19037 19119 19130-19131 19200 19202 19204 19213 19244 19283 19312 19317 19455 19467 19482 19491 19512 19547 19697 19846 19855 19968 20097 21998 22002 22187 22364 22490 22494 22941 22951 22963 22979 22983 22992 23002 23010 23015 23176 23183 23207 23319 23346 23411 23554 23657 23659 23679 23697 23751 23766 23810 23866 23959 24096-24097 24194 24236 24259 24299 26385 26387 26390 26572 26577 27114 27116 27193 27274 27278 27301 27303 27425 27434 27436-27437 27460 27509 27513 27529 27973 27994 28450 28472 28537 28620 29585 29633 29676 29678 29691 30130 30141 30370 30469 31318 31346 31447 31488 31654 31670 31739 31787 31805 31878 32102 32113 36830 36855 40958https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/696/A172?format=asciiGamma-raydefaultJ/A+A/696/A172/tablea1List of alert multiplets for different areasrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintAreathArea threshold (1)deg**2phys.angSizefloatNameName from IceCat-1meta.id;meta.maincharn_Name[*] Note on Name (1)meta.notecharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.maine_RAJ2000Lower error on RAdegdegstat.error;pos.eq.rafloatE_RAJ2000Upper error on RAdegdegstat.error;stat.maxfloatDEJ2000Declination (J2000)degpos.eq.dec;meta.maine_DEJ2000Lower error on DEdegdegstat.error;pos.eq.decfloatE_DEJ2000Upper error on DEdegdegstat.error;stat.maxfloatEnergyReconstructed neutrino eEnergyTeVem.energyfloatAreaUncertainty areadeg**2phys.areafloatSignalnessSignalness (quantity published with each alert event assessing an event's probability to be astrophysical)stat.fit.goodnessfloatClassAlert classification (2)meta.code.classcharJ/A+A/696/A172/tablea2List of alert multiplets for different energy thresholdsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintEthEnergy thresholdTeVinstr.sensitivitycharn_Eth[f] f for the full samplemeta.notecharNameName from IceCat-1meta.id;meta.maincharn_Name[*] Note on Name (1)meta.notecharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.maine_RAJ2000Lower error on RAdegdegstat.error;pos.eq.rafloatE_RAJ2000Upper error on RAdegdegstat.error;stat.maxfloatDEJ2000Declination (J2000)degpos.eq.dec;meta.maine_DEJ2000Lower error on DEdegdegstat.error;pos.eq.decfloatE_DEJ2000Upper error on DEdegdegstat.error;stat.maxfloatEnergyReconstructed neutrino eEnergyTeVem.energyfloatAreaUncertainty areadeg**2phys.areafloatSignalnessSignalness (quantity published with each alert event assessing an event's probability to be astrophysical)stat.fit.goodnessfloatClassAlert classification (2)meta.code.classcharJ/A+A/696/A172/tablea3List of alert multiplets for different signalness thresholdsSignalnessSignalness (quantity published with each alert event assessing an event's probability to be astrophysical)stat.fit.goodnessfloatClassAlert classification (2)meta.code.classcharNameName from IceCat-1meta.id;meta.maincharn_Name[*] Note on Name (1)meta.notecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSignalnessthSignalness thresholdstat.fit.goodnessfloatRAJ2000Right ascension (J2000)degpos.eq.ra;meta.maine_RAJ2000Lower error on RAdegdegstat.error;pos.eq.rafloatE_RAJ2000Upper error on RAdegdegstat.error;stat.maxfloatDEJ2000Declination (J2000)degpos.eq.dec;meta.maine_DEJ2000Lower error on DEdegdegstat.error;pos.eq.decfloatE_DEJ2000Upper error on DEdegdegstat.error;stat.maxfloatEnergyReconstructed neutrino eEnergyTeVem.energyfloatAreaUncertainty areadeg**2phys.areafloat