A neutrino flare candidate potentially associated with X-ray emission from tidal disruption event ATLAS17jrp

TL;DR

The paper investigates whether tidal disruption events can produce high-energy neutrinos by analyzing a decade of IceCube muon-track data for temporally resolved neutrino emission that coincides with X-ray activity in TDEs. Using a time-dependent unbinned likelihood, they search ten X-ray-detected TDEs and find a neutrino flare candidate near ATLAS17jrp with a post-trial p-value of 0.01, peaking about 19 days after X-ray onset and lasting 56 days. A simple lepton-hadronic model with X-ray photons as the target field can explain the neutrino flux around 100 TeV but underpredicts lower-energy neutrinos, suggesting an additional component such as a coronal region. The results highlight the potential TDE–neutrino connection but emphasize that the evidence is not definitive and call for improved X-ray cadence and next-generation neutrino observatories to robustly test this channel.

Abstract

Tidal disruption events (TDEs), in which stars are disrupted by supermassive black holes, have been proposed as potential sources of high-energy neutrinos through hadronic interactions. X-ray-bright TDEs provide dense photon fields conducive to neutrino production via proton-photon ($pγ$) processes. We conducted a time-dependent unbinned likelihood analysis of ten years (2008-2018) of IceCube muon-track data, focusing on ten TDEs with confirmed X-ray detections during this period. We report a neutrino flare candidate spatially and temporally coincident with the TDE ATLAS17jrp, occurring 19 days after the onset of its X-ray activity and lasting for 56 days, with a post-trial $p$-value of 0.01. This significance is modest, representing a hint of an association. We illustrate the neutrino emission using a simple lepton-hadronic model, where X-ray photons serve as target fields. While this model can account for the neutrino data around 100 TeV, the low-energy neutrinos may imply contributions from an additional component. Although constrained by the sample size of X-ray-detected TDEs, these results underscore the need for high-cadence X-ray monitoring and future neutrino observatories to further explore the connection between TDEs and high-energy neutrinos.

Figures (3)

• Figure 1: Top panel: Host-galaxy-subtracted light curve of ATLAS17jrp in the optical, UV, and mid-IR bands. The inset shows the long-term mid-IR light curve from WISE without host-galaxy subtraction. Middle panel: The gray points represent the 0.3-2 keV X-ray luminosities observed by Swift-XRT, while the black points represent the binned X-ray light curve, with the error bars indicating the binned regions. Bottom panel: Time-independent weight of individual events during the multi-band radiation period of ATLAS17jrp. Each vertical line's length represents the weight value of an event observed at a specific MJD, corresponding to the $S_i^{\mathrm{spat}}S_i^{\mathrm{ener}}/B_i^{\mathrm{spat}}B_i^{\mathrm{ener}}$ of IceCube events. The color of each event indicates the reconstructed muon energy (log[GeV]), from which the neutrino energy of a single event can also be inferred. The gray shaded region indicates the best-fitting neutrino flare window.
• Figure 2: Time-dependent analysis test statistic distributions. The purple histogram shows the distribution of $TS$ values derived from 10,000 scrambled trials in the time-dependent analysis. The black dashed line marks the $TS$ value observed at the location of ATLAS17jrp in the time-dependent analysis.
• Figure 3: Multi-messenger SEDs of ATLAS17jrp. The pink, black, and purple curves represent the spectra of the input target photon, the electromagnetic cascade, and all-flavor high-energy neutrino emission produced by our model, respectively. The 'bh-syic', 'pair-syic', and 'pg-syic' components represent the synchrotron and inverse Compton emissions from electrons and positrons produced by the Bethe-Heitler (BH), $\gamma\gamma$, and $p\gamma$ processes, respectively. The grey points represent the X-ray data at the peak time. The blue line indicates the $\gamma$-ray upper limit set by Fermi-LAT. The green solid line shows the best-fit neutrino spectrum obtained through data fitting, with shaded regions representing the $1\sigma$, $2\sigma$, and $3\sigma$ uncertainty regions derived from the same analysis.