Conveners
Searches for Extragalactic astrophysical sources 2
- Anita Reimer (University of Innsbruck)
Searches for Extragalactic astrophysical sources 2
- Anita Reimer (University of Innsbruck)
3C 216 is an extra-galactic radio source classified as a Compact-Steep Spectrum. The source is known to have extended radio structure on kpc scale and a blazar core on pc scale. In general high energy emission is more easily observed in blazars, whose jets are closely aligned with the line of sight. Starting from November 2022 Fermi-LAT observed an enhancement in the gamma-ray activity of 3C...
Very-high-energy (VHE) astrophysics represents a privileged environment for carrying out studies concerning fundamental physics. The high energies achievable in sources such as blazars allow us to access sectors of particle physics that are difficult to explore in laboratory experiments. The ASTRI Gamma Ray Telescope will produce exciting new observational data at VHE, which could provide us...
The production site and process responsible for the highly variable
high-energy emission observed from blazar jets are still debated.
Gravitational lenses can be used as microscopes to investigate the
nature of such sources. We study the broad-band spectral properties and
the high-energy variability of the gravitationally-lensed blazar PKS
1830-211, for which radio observations have...
The intense star-forming activity typical of starburst galaxies results in unique
conditions for high-energy particles. The enhanced supernova rate associated
with such star formation can in fact transfer a large amount of power to non-
thermal particles which, in turn, can lose most of their energy in the dense and
perturbed starburst environment before being able to escape it. I will...
High-energy neutrinos detected by the IceCube Observatory provide a unique opportunity to study the origin of cosmic rays and the nature of the sources producing them. Among the putative birthplaces of astrophysical high-energy neutrinos, blazar jets stand out due to their capability of accelerating particles and providing intense external radiation fields. Blazars are Active Galactic Nuclei...
The IceCube collaboration has recently found evidence for connecting the blazar TXS 0506+056 to high-energy neutrino events. Several other studies have independently investigated the hypothesis of blazars and specific subclasses thereof as neutrino emitters with mixed results, including constraints on the contribution of these sources to the observed astrophysical neutrino flux. As such, open...
The ANTARES neutrino telescope took data for 15 years in the Mediterranean Sea, from 2007 to 2022, and collected a high-purity all-flavour neutrino sample. The search for a diffuse cosmic neutrino signal using this dataset is presented in this contribution. The non-observation of a statistically significant excess of high-energy neutrinos is converted into limits on the properties of the...
The multi-messanger approach has recently paved the way for possible breakthroughs in our comprehension of high energy particle emission in the Universe. Neutrino telescopes are essential for highlighting the hadronic component of these phenomena, also testing possible correlation with known sources of gamma rays. Joint analyses of different telescopes results may provide enhanced...
Neutrinos are interesting elusive particles that can tell us much about our Universe. Due to their neutral, stable, and weakly interacting nature, neutrinos are valuable for studying various astrophysical phenomena including supernovae, solar flares, neutrino oscillations, and dark matter. However, neutrino fluxes at high energies are very small making critical the possibility of having very...
The Pierre Auger Observatory is the most sensitive detector to primary photons with energies above $0.2$ EeV providing unprecedented exposure to ultra-high-energy (UHE) cosmic rays and specifically to UHE photons. The Pierre Auger Observatory measures extensive air showers using a hybrid technique that combines a fluorescence detector (FD) with a ground array of particle detectors (SD). The...
Binaries containing a compact object orbiting a supermassive black hole are thought to be the precursors of gravitational wave events, but their identification has been extremely challenging. Here, we report the X-ray detection of quasi-periodic outflows (QPOuts) from a previously low-luminosity active galactic nucleus after an optical outburst, likely caused by a tidal disruption of a star....
