Hao-Ning He

Diffuse PeV neutrino emission from ultraluminous infrared galaxies

Ultraluminous infrared galaxies (ULIRGs) are the most luminous and intense starburst galaxies in the Universe. Both their star formation rates and their gas surface mass densities are very high, implying a high supernova rate and an efficient energy conversion of energetic protons. A small fraction of these supernovae are the so-called hypernovae, with a typical kinetic energy similar to 10(52) erg and a shock velocity >= 10(9) cm s(-1). The strong shocks driven by hypernovae are able to accelerate cosmic ray protons up to 1017 eV. These energetic protons lose a good fraction of their energy through proton-proton collision when ejected into very dense interstellar media, and as a result, produce high-energy neutrinos (<= 5 PeV). Recent deep infrared surveys provide solid constraints on the number density of ULIRGs across a wide redshift range 0 <= z <= 2.3, allowing us to derive the flux of diffuse neutrinos from hypernovae. We find that at PeV energies, the diffuse neutrinos contributed by ULIRGs are comparable to atmosphere neutrinos with the flux of 2 x 10(-9) GeV cm(-2) s(-1) sr(-1) by assuming the injected cosmic ray spectrum to be dN(p)/d epsilon(p) proportional to epsilon(p)(-2). DOI: 10.1103/PhysRevD.87.063011

AMS-02 positron excess: New bounds on dark matter models and hint for primary electron spectrum hardening ✩

The data collected by ATIC, CREAM and PAMELA all display remarkable cosmic ray nuclei spectrum hardening above the magnetic rigidity similar to 240 GV. One natural speculation is that the primary electron spectrum also gets hardened (possibly at similar to 80 CV) and the hardening partly accounts for the electron/positron total spectrum excess discovered by ATIC, HESS and Fermi-LAT. If it is the case, the increasing behavior of the subsequent positron-to-electron ratio will get flattened and the spectrum hardening should be taken into account in the joint fit of the electron/positron data otherwise the inferred parameters will be biased. Our joint fits of the latest AMS-02 positron fraction data together with the PAMELA/Fermi-LAT electron/positron spectrum data suggest that the primary electron spectrum hardening is needed in most though not all modelings. The bounds on dark matter models have also been investigated. In the presence of spectrum hardening of primary electrons, the amount of dark-matter-originated electron/positron pairs needed in the modeling is smaller. Even with such a modification, the annihilation channel chi chi -> mu(+) mu(-) has been tightly constrained by the Fermi-EAT Galactic diffuse emission data. The decay channel chi -> mu(+) mu(-) is found to be viable

HIGH-ENERGY EMISSION OF GRB 130427A: EVIDENCE FOR INVERSE COMPTON RADIATION

A nearby superluminous burst GRB 130427A was simultaneously detected by six gamma-ray space telescopes (Swift, the Fermi GLAST Burst Monitor (GBM)/Large Area Telescope, Konus-Wind, SPI-ACS/INTEGRAL, AGILE, and RHESSI) and by three RAPTOR full-sky persistent monitors. The isotropic gamma-ray energy release is similar to 10(54) erg, rendering it the most powerful explosion among gamma-ray bursts (GRBs) with a redshift z 1 TeV neutrinos from GRB 130427A by IceCube are discussed.

Short GRBs: Opening Angles, Local Neutron Star Merger Rate, and Off-axis Events for GRB/GW Association

The jet breaks in the afterglow lightcurves of short gamma-ray bursts (SGRBs), rarely detected so far, are crucial for estimating the half-opening angles of the ejecta (

Model-dependent estimate on the connection between fast radio bursts and ultra-high energy cosmic rays

theta_{rm j}

Evaluating the Bulk Lorentz Factors of Outflow Material: Lessons Learned from the Extremely Energetic Outburst GRB 160625B

) and hence the neutron star merger rate. In this work we report the detection of jet decline behaviors in GRB 150424A and GRB 160821B and find

GRB 131231A: IMPLICATIONS OF THE GeV EMISSION

theta_{rm j}sim 0.1

HIGH ENERGY EMISSION OF GRB 130821A: CONSTRAINING THE DENSITY PROFILE OF THE CIRCUM-BURST MEDIUM AS WELL AS THE INITIAL LORENTZ FACTOR OF THE OUTFLOW

rad. Together with five events reported before 2015 and other three identified recently (GRB 050709, GRB 060614 and GRB 140903A), we have a sample consisting of nine SGRBs and one long-short GRB with reasonably estimated

HESS J1427−608: AN UNUSUAL HARD, UNBROKEN γ-RAY SPECTRUM IN A VERY WIDE ENERGY RANGE

theta_{rm j}

TeV-PeV neutrinos over the atmospheric background: originating from two groups of sources?

. In particular, three {it Swift} bursts in the sample have redshifts