An Updated Source List for IceCube Neutrino Cluster Alerts Caterina Boscolo Meneguolo1,2*, E. Bernardini1,2, J.-P. Jonckheere1, S. Mancina1,2 for the IceCube Collaboration 1Università degli Studi di Padova, 2INFN Padova, *Speaker:
[email protected] IceCube’s Gamma-ray Follow-Up (GFU) platform identifies potential neutrino flares in real-time [1]. Likelihood-based analysis: Source hypotheses and sliding time windows tested for significant clustering of neutrinos. Soon: public alerts So far: private alerts to Imaging Air Cherenkov Telescopes (IACTs) for follow-up observations. Since 2019: 339 sources, mostly Fermi-LAT 𝛾-ray bright blazars, selection based on IACTs' detectability: • redshift < 1 • cut in elevation • extrapolated flux (>TeV) + EBL correction at reach for IACTs' sensitivity The Current Source List •Improved insights on candidate neutrino emitters •Updated catalogs available •Public alerts to engage observations at other wavelengths (e.g., X-ray) •Focus on IceCube sensitivity favoring the Horizon and Northern sky Figure 1. Sensitivity and discovery potential for time-integrated point-source analysis. Assumed power-law spectrum 𝑑𝑁/𝑑𝐸 ∝𝐸𝛾. 34% of current GFU sources in the updated selection: A big change! •new focus on IceCube sensitivity: Horizon + Northern Sky •Including distant blazars, X-ray bright Seyfert galaxies and Galactic sources. IN PROGRESS to be complemented by a TeV 𝛾-ray motivated selection maintaining a focus on IACTs' sensitivity. Expected ~350 sources in total. Figure 3. Updated GFU-cluster source list (color) compared to the current IACT-motivated catalog (grey). Equatorial coordinates. GFU-Cluster Alerts Promising source classes selected a priori based on observations and models. Within each selection, sources from relevant input catalogs are ranked according to a Figure of Merit (FoM) Selection Motivation Sub -selection Catalog Flux for FoM Sources GeV 𝛾ray motivated AGN (e.g., blazars, TXS 0506+056). GeV emission highly variable and well - characterized. AGN 4FGL [2] Photon Flux (1-100 GeV) 200 keV Xray motivated AGN (e.g., Seyfert galaxies) and Galactic sources (e.g. Microquasars). Neutrinos produced and 𝛾-ray reprocessed in optically thick environments. AGN BASS [3] Intrinsic Flux (14-195 keV) 44 Galactic Sources Swift/BAT [4] Observed Flux (14-195 keV )10 Microquasars Refs . [5, 6,7] - 12 Unique sources 259 Figure of Merit = Source Flux from catalog IC Sensitivity at source Dec Source-List Alerts Monitoring pre-selected sources enhances sensitivity with respect to All-Sky searches, for lower trial factors. Refine the selection of the most promising neutrino sources to be monitored The Goal Selection Criteria [1] IceCube Collaboration PoS(ICRC2023)1500. [2] The Fourth Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope: Data Release 3 (M. Ajello et al 2022 ApJS 263 24 ) [3] Swift/BAT Spectroscopic Survey II (M. J. Koss et al 2022 ApJS 261 1) [4] 157-Month Swift/BAT hard X-ray catalog (K. Oh et al 2018 ApJS 235 4) [5] C. Distefano et al 2002 ApJ 575 378 [6] D. Kantzas et al. MNRAS 524 no. 1, (06, 2023) 1326–1342. [7] LHAASO Collaboration (Oct., 2024) arXiv:2410.08988. The Updated Source List References Figure 2. Neutrinos and 𝛾 rays co-produced in cosmic ray (CR) acceleration (pp or p 𝛾 interactions). Neutrinos travel unabsorbed, while 𝛾 rays can be reprocessed to lower energies in optically-thick environments.
