Related papers: The Fundamental Plane Relation for Gamma-Ray Pulsa…
A recent work has found a tight global relation between the GRB prompt fluence, peak flux (based on the optimum time scale determined from the Bayesian Blocks-based analysis) and duration using data from the Fermi Gamma-Ray burst monitor,…
To constrain the giant pulse (GP) emission mechanism and test the model of Lyutikov (2007) of GP emission, we are carrying out a campaign of simultaneous observations of the Crab pulsar between gamma-rays (Fermi) and radio wavelengths. The…
Rotation-powered pulsars represent the main class of identified gamma-ray sources in the Galaxy. The wealth of observational data collected by the AGILE and Fermi gamma-ray space telescopes in the GeV range, and by ground-based Cherenkov…
The blazar 4C 31.03 recently underwent a major gamma-ray outburst at the beginning of 2023 after a prolonged quiescent phase. Fermi-LAT reported a daily average flux of 5x10^-6 phs cm^-2 s^-1, which is about 60 times its average value. We…
We present an interpretation of the phenomenological relations between the spectral peak, isotropic luminosity and duration of long gamma ray bursts that have been discovered by Amati et al., Ghirlanda et al., Firmani et al., and Liang &…
The X-ray, Ultraviolet, Optical emission from radio-quiet AGNs, black hole binaries, and other compact sources, in general, follow a lognormal flux distribution, a linear rms-flux relation, and a (broken) power-law power spectral densities…
In this paper, we study the photon-photon pair production optical depth for gamma-rays with energies from 10 to 200 GeV emitted by powerful blazars due to the diffuse radiation field of broad line region (BLR). There are four key parameters…
Recently, under the assumption that the Doppler effect of the relativistically expanding fireball surface is important, Qin et al. showed that in most cases the power law relationship between the pulse width and energy of gamma-ray bursts…
We present the fourth Fermi Large Area Telescope catalog (4FGL) of gamma-ray sources. Based on the first eight years of science data from the Fermi Gamma-ray Space Telescope mission in the energy range from 50 MeV to 1 TeV, it is the…
We start by studying a small set of objects characterized by photometric profiles that have been pointed out to deviate significantly from the standard R^{1/4} law. For these objects we confirm that a generic R^{1/n} law, with n a free…
The standard model characterizing the gamma-ray burst (GRB) spectrum invokes a four-parameter empirical function, the so-called the BAND model. An alternative model named cutoff power law (COMP) implements a power law with an exponential…
Most pulsars observed by the Fermi LAT have gamma-ray luminosities scaling with spindown power Edot as L_gamma (Edot x 10^33 erg/s)^{1/2}. However, there exist one detection and several upper limits an order of magnitude or more fainter…
Axion-like particles (ALPs) are predicted in some well-motivated theories beyond the Standard Model. The TeV gamma-rays from active galactic nuclei (AGN) suffer attenuation by the pair production interactions with the cosmic background…
Gamma sources with high flux and spectral densities are the main requirements for new nuclear physics experiments to be performed in several worldwide laboratories and envisaged in the ELI-NP (Extreme Light Infrastructure-Nuclear Physics)…
Context: Using the Illustris-1 and IllustrisTNG-100 simulations we investigate the properties of the Fundamental Plane (FP), that is the correlation between the effective radius Re, the effective surface intensity Ie and the central stellar…
The light profiles of elliptical (E) galaxies are known to display small systematic deviations (0.1-0.2 mag.) from the R^1/4 law. In this paper we show that the senses and amplitudes of these departures can be naturally accounted for by a…
Fermi-LAT analyses show that the gamma-ray photon spectral indices Gamma_gamma of a large sample of blazars correlate with the vFv peak synchrotron frequency v_s according to the relation Gamma_gamma = d - k log v_s. The same function, with…
We re-examine the outer gap size by taking the geometry of the dipole magnetic field into account. Furthermore, we also consider that instead of taking the gap size at half of the light cylinder radius to represent the entire outer gap it…
We present results of Compton Gamma-Ray Observatory EGRET observations of the unidentified high-energy gamma-ray sources 2EG J1049-5847 (GEV J1047-5840, 3EG J1048-5840) and 2EG J1103-6106 (3EG J1102-6103). These sources are spatially…
We compare population synthesis results for inner and outer magnetosphere emission models with the various characteristics measured in the first LAT pulsar catalogue for both the radio-loud and radio-weak or radio-quiet gamma-ray pulsars.…