Dust-obscured radio-emitting tidal disruption event coincident with a high-energy neutrino event

TL;DR

This work addresses the origin of high-energy neutrinos by systematically searching for neutrino-associated, dust-rich TDEs. By cross-matching mid-infrared outbursts with radio transients and IceCube gold-track events, the authors identify J1513+3111 as a spatially and temporally coincident source with IC170514B, and conduct multi-epoch radio studies to model the outflow–CNM interaction via equipartition-based synchrotron analysis. The results indicate a radio-emitting region of $R_{eq}\sim10^{17}$ cm with total nonthermal energy up to $\sim10^{51}$ erg, and a compact VLBI source with $T_b>5\times10^{6}$ K, supporting a non-thermal outflow scenario. The authors argue that while $p\gamma$ processes with IR/UV photons are inefficient for the sub-PeV neutrino, $pp$ collisions in outflow-Cloud interactions provide a plausible mechanism, predicting measurable multi-messenger signatures for future identifications.

Abstract

Despite the growing number of high-energy neutrinos (TeV-PeV) detected by IceCube, their astrophysical origins remain largely unidentified. Recent observations have linked a few tidal disruption events (TDEs) to the production of high-energy neutrino emission, all of which display dust-reprocessed infrared flares, indicating a dust- and gas-rich environment. By cross-matching the neutrino events and a sample of mid-infrared outbursts in nearby galaxies with transient radio flares, we uncover an optically obscured TDE candidate, SDSS J151345.75 $+$ 311125.2, which shows both spatial and temporal coincidence with the sub-PeV neutrino event IC170514B. Using a standard equipartition analysis of the synchrotron spectral evolution spanning 605 days post mid-infrared discovery, we find a little evolution in the radio-emitting region, with a kinetic energy up to $10^{51}$ erg, depending on the outflow geometry and shock acceleration efficiency assumed. High-resolution European VLBI Network imaging reveals a compact radio emission that is unresolved at a scale of $<$ 2.1 pc, with a brightness temperature of $T_b>5\times10^6$ K, suggesting that the observed late-time radio emission might originate from the interaction between a decelerating outflow and a dense circumnuclear medium. If the association is genuine, the neutrino production is possibly related to the acceleration of protons through pp collisions during the outflow expanding process, implying that the outflow-cloud interaction could provide a physical site with a high-density environment for producing the sub-PeV neutrinos. Such a scenario can be tested with future identifications of radio transients coincident with high-energy neutrinos.

Figures (6)

• Figure 1: Left panel: Localization of J1513+3111 and IC170514B. The blue rectangular shows the 90% CL containment region of IC170514B. Right panel: The mid-infrared light curves of J1513+3111 observed by WISE. The vertical dashed line marks the arrival time of matched high-energy neutrino event IC170514B, which delayed the peak of mid-infrared emission by $\sim$109 days.
• Figure 2: Left panel: Radio SED and its evolution over three epochs, using the data taken from VLA, GMRT,and EVN observations. For the non-detections, the corresponding 3$\sigma$ upper limits on flux density are shown. Data for the three epochs are represented by magenta diamonds (epoch I), blue triangles (epoch II), and orange squares (epoch III). The color-coded lines represent the best fit to each SED from our MCMC modeling analysis, which are the model realizations on a basis of 500 random samples from the MCMC chains. Right panel: The radio flux density evolution of J1513+3111 at 5.5 GHz. To better illustrate the transient nature of the radio emission, we show the 3$\sigma$ upper limit on the pre-flare radio flux at 1.4 GHz from FIRST survey (Table \ref{['flux']}), but with an arbitrary time relative to the MIR discovery.
• Figure 3: EVN image of J1513+3111 at 4.93 GHz, with a deconvolved size of 3.61 mas $\times$ 1.58 mas. At the mas scale, J1513+3111 remains compact with no significant extended emission. The gray filled ellipse in the right corner represents the shape of the beam.
• Figure 4: The 5.5 GHz radio luminosity evolution of J1513+3111. For non-detection, the corresponding 3$\sigma$ upper limit on luminosity is shown, with an arbitrary time relative to the neutrino arrival. For AT2019dsg, we present only the data observed at $\sim$5-6 GHz. For AT2019aalc, we show the 3 GHz luminosity evolution observed by VLASS, suggesting that the source experienced a radio brightening by a factor of 2 on a timescale of less than 1.5 years. Note that there are no dedicated radio observations of AT2019aalc during the period of neutrino arrival, until ATCA observations that were performed about three years after the detection of neutrino Veres2024.
• Figure B1: Posterior distribution of the parameters spectral peak frequency $\nu_p$ and flux density at $F_{\nu,p}$, obtained by fitting the synchrotron spectrum to the observed radio SED. The dashed lines represent the 68% quantile intervals.