Related papers: AGILE observations of Supernova Remnants
Recent astronomical observations reveal that Active Galactic Nuclei (AGN) are sources of high-energy radiation. For example, the Fermi-LAT and Hess telescopes have detected gamma-ray emissions from the cores of several types of AGN's. Even…
Active Galactic Nuclei (AGN) are sources of high-energy gamma-rays and are considered to be promising candidates to be sources of high-energy cosmic rays and neutrinos as well. We present and discuss various models for ion acceleration and…
In recent years some efforts have been made to identify active sources capable of accelerating particles up to $10^{15}$ eV, known as PeVatrons. Measurements of TeV ($10^{12}$ eV) gamma-rays from supernova remnants (SNRs) have shown that…
Extragalactic cosmic ray populations are important diagnostic tools for tracking the distribution of energy in nuclei and for distinguishing between activity powered by star formation versus active galactic nuclei (AGNs). Here, we compare…
Very recent gamma-ray observations of G120.1+1.4 (Tycho's) supernova remnant (SNR) by Fermi-LAT and VERITAS provided new fundamental pieces of information for understanding particle acceleration and non-thermal emission in SNRs. We want to…
Growing supermassive black holes (Active Galactic Nuclei; AGN) release energy with the potential to alter their host galaxies and larger-scale environment; a process named "AGN feedback". Feedback is a required component of galaxy formation…
Using gamma-ray data collected by the Astrorivelatore Gamma ad Immagini LEggero (AGILE) satellite over a period of almost one year (from 2007 July to 2008 June), we searched for pulsed signals from 35 potentially interesting radio pulsars,…
Cygnus X-3 (Cyg X-3) is a well-known microquasar producing variable emission at all wavelengths. Cyg X-3 is a prominent X-ray binary producing relativistic jets, and studying its high energy emission is crucial for the understanding of the…
Supernova remnants (SNRs) are the most attractive candidates for the acceleration sites of Galactic cosmic rays. We report the detection of GeV $\gamma$-ray emission with the Pass 8 events recorded by Fermi Large Area Telescope (Fermi-LAT)…
We examine the near-infrared (NIR) emission from low-luminosity AGNs (LLAGNs). Our galaxy sample includes 15 objects with detected 2-10 keV X-ray emission, dynamical black hole mass estimates from the literature, and available Gemini/NIFS…
Cosmic nucleosynthesis co-produces unstable isotopes, which emit characteristic gamma-ray emission lines upon their radioactive decay that can be measured with SPI on INTEGRAL. High spectral resolution allows to derive velocity constraints…
Context. The supernova remnant (SNR) W44 and its surroundings are a prime target for studying the acceleration of cosmic rays (CRs). Several previous studies established an extended gamma-ray emission that is set apart from the radio shell…
New generational very-high-energy telescope arrays have been detecting more than 120 TeV {\gamma}-ray sources. Multi-wavelength observations on these Gamma-ray sources have proven to be robust in shedding light on their nature. The coming…
We review the characteristics of nucleosynthesis and radioactivities in 'Hypernovae', i.e., supernovae with very large explosion energies ($ \gsim 10^{52} $ ergs) and their $\gamma$-ray line signatures. We also discuss the $^{44}$Ti line…
The e$^+$ e$^-$ annihilation line at 511 keV provides a unique probe for studying the distribution and origin of positrons in our Galaxy. The SPI spectrometer on INTEGRAL has observed this gamma-ray line for two decades. We analyze 20 years…
The SuperAGILE (SA) instrument is a X-ray detector for As- trophysics measurements, part of the Italian AGILE satellite for X-Ray and Gamma-Ray Astronomy launched at 23/04/2007 from India. SuperAGILE is now studying the sky in the 18 - 60…
In the frame of the Astronomical Validation activities for the 64m Sardinia Radio Telescope, we performed 5-22 GHz imaging observations of the complex-morphology supernova remnants (SNRs) W44 and IC443. We adopted innovative observing and…
The author reviews a model for the emission of high energy cosmic rays, gamma-rays and neutrinos from AGN (Active Galactic Nuclei) that he has proposed since 1985. Further discussion of the knee energy phenomenon of the cosmic ray energy…
Kepler's supernova remnant (SNR) which is produced by the most recent naked-eye supernova in our Galaxy is one of the best studied SNRs, but its gamma-ray detection has eluded us so far. Observations with modern imaging atmospheric…
We present optical SuperNova Integral Field Spectrograph (SNIFS) integral field spectroscopy, Hubble Space Telescope optical imaging, Chandra X-ray imaging, and Very Large Array radio interferometry of the merging galaxy 2MASX…