arXiv subjects

Rong-Lan Li

Publications and source records attributed to Rong-Lan Li.

9 recordsLinked to original sources

arXiv2026

Constraints on neutrino emission and hadronic flux from 1LHAASO catalog $γ$-ray sources

IceCube has detected neutrino emission from the Galactic Plane (GP) at a significance of $4.5σ$, though its origin remains uncertain. Utilizing ten years of IceCube muon-track data, we investigate potential correlations between the GP neutrinos and $γ$-ray sources in the first LHAASO catalog (1LHAASO). To avoid issues caused by spectral extrapolation, this analysis focuses on sources detected by the Water Cherenkov Detector Array (WCDA). We employ an unbinned likelihood analysis to search for neutrino emission and constrain the hadronic $γ$-ray component of these sources. Neither single-source searches nor stacking analyses reveal significant neutrino signals. The stacking analysis indicates that the 1LHAASO WCDA population contributes at most $\sim$20\% to the diffuse GP neutrino flux measured by IceCube. The total hadronic contribution to the cumulative $γ$-ray emission from all WCDA sources is constrained to be at most $\sim$$60\%$, suggesting a predominantly leptonic origin for the $γ$-ray emission from the LHAASO source population. Even accounting for unresolved sources below the detection threshold, we estimate the total neutrino flux from all discrete sources (resolved plus unresolved) reaches at most about 40\% of the observed GP neutrino flux. These results support that the bulk of the GP neutrino emission is mainly from truly diffuse processes, i.e., cosmic-ray interactions with the interstellar medium, rather than from unresolved point sources.

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arXiv2026

Investigating the correlations between IceCube high-energy neutrinos and Fermi-LAT $γ$-ray observations. II

Given that gamma rays with energies larger than TeV are severely absorbed by background radiation fields, for many extragalactic sources, the GeV-TeV gamma-ray observations are the messengers that are closest in energy to the TeV-PeV neutrinos observed by IceCube. Investigating whether there is a correlation between the gamma-ray and neutrino observations can help us identify high-energy neutrino sources and determine which sources are the main contributors to the all-sky diffuse neutrino flux of IceCube. In previous work, we have already studied the possible gamma-neutrino correlations by analyzing 10 years of IceCube public muon-track data. In this work, we further investigate such correlations by employing the IceCube p-value sky map of the scan for point sources. We examine the spatial associations of hotspots in the neutrino sky map with various gamma-ray source samples: the third Fermi-LAT catalog of high-energy sources (3FHL), LAT 14-year source catalog (4FGL), the fourth catalog of active galactic nuclei (4LAC) and subsets of these samples. Among all the samples, the 3FHL sample shows a possible correlation with the neutrino hotspots with a pre-trial p-value of $9.0\times10^{-5}$ ($\sim 3.9\,σ$), corresponding to a post-trial significance of $\sim1.7\,σ$. However, this is found to be caused by three already known neutrino sources/source candidates: NGC 1068, TXS 0506+056, and PKS 1424+240.

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arXiv2026

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

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.

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arXiv2025

Search for neutrino emission from LHAASO observed Microquasar with IceCube 10-year data

The Large High Altitude Air Shower Observatory (LHAASO) has detected ultra-high-energy (UHE; E>100 TeV) gamma-ray emission from five microquasars, suggesting their potential as Galactic PeV cosmic-ray accelerators. At these energies, the Klein-Nishima effect strongly suppresses leptonic processes, making neutrinos observation a crucial test for hadronic acceleration. We present a search for neutrino emission from these LHAASO-identified Microquasars using ten years of IceCube muon-track data. No significant neutrino signal was found in either single-source or stacking analyses. Our stacking result further shows that the studied microquasars population can only account for a small fraction of the diffuse neutrino flux along the Galactic Plane. Finally, we demonstrate that new-generation neutrino telescopes, such as HUN, will have the sensitivity to probe harmonic emission from these candidate PeVatrons.

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arXiv2024

Evidence for the Sombrero Galaxy as an Accelerator of the Highest-Energy Cosmic Rays

Ultrahigh-energy cosmic rays (UHECRs) are the highest energy messenger from space, with energies exceeding 1 EeV. Although UHECRs were discovered over 60 years ago, their origin still remains a mystery. Pinpointing sources of UHECRs is crucial for understanding the extreme astrophysical processes that accelerate particles to such extraordinary energies. We searched for UHECR multiplets via analyzing 17 years of data with energies greater than 40 EeV from the Pierre Auger Observatory. A spatial association is found between a multiplet of $25.7^{+6.2}_{-7.0}$ cosmic rays and the Sombrero galaxy with a local (global) significance of $4.5~σ~(3.3~σ)$. The Sombrero galaxy hosts a supermassive central black hole with a mass of $\sim1\times 10^9 M_{\odot}$ and exhibits large-scale radio lobes and jets. Our finding provides critical evidence on active supermassive black holes as the source of the highest-energy cosmic rays.

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arXiv2024

Dark matter search in dwarf irregular galaxies with ten years of data from the IceCube neutrino observatory

Dwarf irregular galaxies (dIrrs), as rotationally-supported systems, have more reliable J-factor measurements than dwarf spheroidal galaxies and have received attention as targets for dark matter detection in recent years. In this paper, we use 10 years of IceCube muon-track data and an unbinned maximum-likelihood-ratio method to search for neutrino signals beyond the background from the directions of 7 dIrrs, aiming to detect neutrinos produced by heavy annihilation dark matter. We do not detect any significant signal. Based on such null results, we calculate the upper limits on the velocity-averaged annihilation cross section for 1 TeV - 10 PeV dark matter. Our limits, although weaker than the strictest constraints in the literature in this mass range, are also a good complement to the existing results considering the more reliable J-factor measurements of dIrrs.

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arXiv2023

Using $γ$-ray observations of dwarf spheroidal galaxies to test the possible common origin of the W-boson mass anomaly and the GeV $γ$-ray/antiproton excesses

A recent result from Fermilab suggests that the measured W-boson mass deviates from the prediction of the Standard Model (SM) with a significance of $>7σ$, and there may exist new physics beyond the SM. It is proposed that the inert two Higgs doublet model (i2HDM) can well explain the new W-boson mass. Meanwhile, the lightest neutral scalar $S$ in the i2HDM can be stable and play the role of dark matter with a preferred dark matter mass of $\sim 54-74$ GeV. It is also found that part of the parameter space of this model can explain both the Galactic center GeV gamma-ray excess detected by $Fermi$-LAT and the GeV antiproton excess detected by AMS-02 through a $SS\rightarrow WW^*$ annihilation. In this paper, we aim to test the possible common i2HDM origin of the three anomaly/excesses using the $Fermi$-LAT observations of Milky Way dwarf spheroidal (dSph) galaxies. We perform single and stacking analyses on 19 dSphs that have J-factor measurements. We find that our upper limits are below the favored parameters and seems to be able to exclude the possibility of a common origin of the three anomaly/excesses. However, because the J-factor measurements include relatively large uncertainties, which come from the measurements of stellar kinematics, whether this model could be reliably excluded needs to be further confirmed by future observations.

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arXiv2023

Searching for dark-matter induced neutrino signals in dwarf spheroidal galaxies using 10 years of IceCube public data

This study searches for neutrino signals from 18 dwarf spheroidal galaxies (dSphs) using 10 years of publicly available muon-track data of the IceCube neutrino observatory. We apply an unbinned likelihood analysis on each of these dSphs to derive the significance the putative neutrino emission. To further enhance our sensitivity, we also stack all dSphs together to perform a joint analysis. However, no significant neutrino emission signal was detected in either the single-source or stacking analysis. Based on these null results, we derive constraints on the annihilation cross section of dark matter particles. Compared to the existing literature, our constraints via the channel $χχ\rightarrowμ^+μ^-$ are comparable to the ones from the VERITAS observations of dSphs.

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arXiv2022

Investigating the correlations between IceCube high-energy neutrinos and Fermi-LAT gamma-ray observations

We use 10 years of publicly available IceCube data to investigate the correlations between high-energy neutrinos and various Fermi-LAT gamma-ray samples. This work considers the following gamma-ray samples: the third Fermi-LAT catalog of high-energy sources(3FHL), >100GeV Fermi-LAT events, LAT 12-year source catalog(4FGL), the fourth catalog of active galactic nuclei(4LAC) and subsets of these samples. For each sample, both a single-source analysis and a stacking analysis are performed. We find no indication that the sources in these samples produce significant high-energy neutrinos. From the null search results, we infer that each source population can produce no more than ~2.5%-36%(at the 95% confidence level, for a spectral index of -2.5) of the IceCube's diffuse neutrino flux. Since we are using a larger (10years) dataset of IceCube neutrinos the constraints are improved by a factor of ~2 compared to those based on 3 years of data.

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