We investigate ultra-fast outflows (UFOs) of active galactic nuclei (AGN) as potential sites for the production of the highest-energy cosmic rays, focusing on cosmic-ray nuclei, a previously unexplored aspect. These mildly-relativistic large-scale outflows, with velocities reaching up to half the speed of light, are ubiquitous in AGN. We numerically study the processes that affect the maximum...
Since neutral particles are not deflected by magnetic fields, they are a valuable tool for studying the sources of ultra-high-energy cosmic rays (UHECRs). It is expected that sources of UHECRs will also produce neutrons through nuclear interactions and photo-pion production near the source. Free neutrons undergo beta decay, traveling a typical distance of $9.2\times(E/1\,\mathrm{EeV})$ kpc. As...
Gain Molecular Clouds (GMCs) are massive reservoirs of gas and dust, with masses typically around 10$^{5}$ M$_⊙$. GMCs are critical regions for studying Cosmic Ray (CR) interactions and their effects on interstellar medium (ISM). We selected six GMCs, which are at high galactic latitude and in the field of view of LHAASO. These GMCs are within 1 kpc distance from the Sun. By using the data...
Young massive stellar clusters have recently brought attention as PeVatrons candidates, to explain the knee of the cosmic ray spectrum and how protons can be accelerated to such energy scale in galactic sources. The new detector LHAASO is the first to probe well the photon detection band >0.1 PeV, that can correspond to multi-PeV hadronic cosmic rays. Thus, it enables the use of its gamma-ray...
Since the discovery of TeV halos around the Geminga and B0656+14 pulsars by the HAWC experiment in 2017, many theoretical efforts have been dedicated to understanding this source class. Indeed, assuming that they are probing the environment outside their parent supernova remnant (SNR), the gamma-ray emission hints at a confinement of high energy particles that challenges our current...
An advanced LIGO and Virgo's third observing run brought another binary neutron star merger (BNS) and the first neutron-star black hole mergers. While no confirmed kilonovae were identified in conjunction with any of these events, continued improvements of analyses surrounding GW170817 allow us to project constraints on the Hubble Constant ($H_0$), the Galactic enrichment from $r$-process...
With high duty cycle, wide field of view and high sensitivity, LHAASO-WCDA is a promising facility to monitor very-high-energy transient extra-galactic sources unbiasedly. We developed an real-time monitoring system based on LHAASO-WCDA observations which will send alerts within Half a day at most if there is any detection. In the past one year of operation, the system has detected more then...
KM3NeT is a neutrino telescope located in the depths of the Mediterranean Sea. It consists of two sites, ARCA (off the Sicilian coast of Capo Passero) dedicated to the study of astrophysical neutrinos and ORCA (off the French coast of Toulon), optimised for GeV - TeV energies.
The two detectors are still under construction and should be completed in the next few years. However, the first...
In the last decade, neutrino telescopes have probed astrophysical sources to probe cosmic ray acceleration mechanisms and shine light on properties previously unseen. The main neutrino telescopes nowadays are IceCube in the Antarctic ice and KM3NeT under construction in the Mediterranean Sea. These Cherenkov based neutrino telescopes are specially built for neutrino astronomy at TeV and higher...
Realtime alerts have become a cornerstone of multi-messenger astronomy since the past decade. Electromagnetic (EM) observatories operating in various wavelength-bands regularly follow up alerts issued by other EM facilities and more commonly by the neutrino and gravitational wave (GW) observatories across the world. While the localization of GW wave alerts in the sky is rather large at...
The Central Molecular Zone at the Galactic Centre hosts the most massive and densest molecular clouds in our Galaxy. The mass of the clouds could be inferred from the infrared emission of the dust, or line emissions from tracers like CS and CO, but different methods having different assumptions sometimes yield inconsistent results. We propose that neutrinos can act as a new gas tracer to...
Active galactic nuclei are compelling candidates for astrophysical neutrino sources, as suggested by the detection of a high-energy neutrino positionally consistent with the flaring blazar TXS 0506+056 and evidence of neutrino emission from the nearby Seyfert galaxy NGC 1068. Our recent studies based on the IceCube time-integrated sky maps provided evidence of a statistically significant...
One of the central questions in high-energy astrophysics is the origin of high-energy
cosmic rays and neutrinos. The Seyfert 2 Compton-thick AGN NGC 1068 stands out as a
promising candidate for high-energy neutrino emission, with a significance level of 4.2𝜎.
Various models have been proposed to explain the multi-messenger emission associated
with this source. X-ray data are crucial for...
Coincident quasi-periodic oscillations are observed in the gamma-ray, optical and radio light curves from the blazer J1048+7143. While in gamma rays and optical, the flares consist of two subflares each, the radio emissions show a Gaussian-like flare structure.
Here, we show that all these flares are consistent with a supermassive binary black hole at the center of this blazar, caused by...
