Related papers: The multi-frequency multi-temporal sky
Cosmic objects emit throughout the electro-magnetic spectrum, from radio waves to very high-energy gamma rays. Some spectral regions can be observed from the ground, but space instrumentation is needed for most of them. Some spectral…
The last few years have seen gamma-ray astronomy maturing and advancing in the field of time-domain astronomy, utilizing source variability on timescales over many orders of magnitudes, from a decade down to a few minutes and shorter,…
Many decades ago a search for variable stars was one of the main areas of astrophysical research. Such searches, conducted with CCD detectors rather than with photographic plates, became a by-product of several projects seeking…
Conventional techniques that measure rapid time variations are inefficient or inadequate to discover and observe rapidly pulsating astronomical sources. It is therefore conceivable that there exist some classes of objects pulsating with…
Firmamento (https://firmamento.hosting.nyu.edu) is a new-concept web-based and mobile-friendly data analysis tool dedicated to multi-frequency/multi-messenger emitters, as exemplified by blazars. Although initially intended to support a…
The extragalactic gamma-ray sky is dominated by two classes of sources: Gamma-Ray Bursts (GRBs) and radio loud active galactic nuclei whose jets are pointing at us (blazars). We believe that the radiation we receive from them originates…
The advent of large data-set in cosmology has meant that in the past 10 or 20 years our knowledge and understanding of the Universe has changed not only quantitatively but also, and most importantly, qualitatively. Cosmologists rely on data…
Astrophysics has become a domain extremely rich of scientific data. Data mining tools are needed for information extraction from such large datasets. This asks for an approach to data management emphasizing the efficiency and simplicity of…
Despite the large budgets spent annually on astronomical research equipment such as telescopes, instruments and supercomputers, the general trend is to analyse and view the resulting datasets using small, two-dimensional displays. We report…
We present preliminary results of a statistical analysis obtained with a sample of blazars observed at the Perugia Astronomical Observatory since 1992. We briefly show how these statistical results can be useful to discriminate faint…
The field of gamma-ray astronomy has experienced impressive progress over the last decade. Thanks to the advent of a new generation of imaging air Cherenkov telescopes (H.E.S.S., MAGIC, VERITAS) and thanks to the launch of the Fermi-LAT…
Over the past few decades impressive progress has been made in the field of photon polarimetry, especially in the hard X-ray and soft gamma-ray energy regime. Measurements of the linear degree of polarization for some of the most energetic…
In recent years, observational $\gamma$-ray astronomy has seen a remarkable range of exciting new results in the high-energy and very-high energy regimes. Coupled with extensive theoretical and phenomenological studies of non-thermal…
From an observational perspective cosmology is today in excellent shape - advances in instrumentation and data processing have enabled us to study the universe in detail back to when the first galaxies formed, map the fluctuations in the…
High-energy photons are a powerful probe for astrophysics and for fundamental physics in extreme conditions. During the recent years, our knowledge of the most violent phenomena in the Universe has impressively progressed thanks to the…
High-energy cosmic neutrinos carry unique information about the most energetic non-thermal sources in the Universe. This white paper describes the outstanding astrophysics questions that neutrino astronomy can address in the coming decade.…
The Astrophysics of microquasars - galactic miniatures of the far distant quasars - has become one of the most active fields of modern Astronomy in recent years. Here I review the astronomical methods used for the investigation of these…
Active galactic nuclei come in many varieties. A minority of them are radio-loud, and exhibit two opposite prominent plasma jets extending from the proximity of the supermassive black hole up to megaparsec distances. When one of the…
Since its launch in 2008 the Fermi Large Area Telescope provides regular monitoring of a large sample of gamma-ray sources on time scales from hours to years. Together with observations at other wavelengths it is now possible to study…
Recent ground based and space telescopes that detect high energy photons from a few up to hundreds of gigaelectron volts (GeV) have opened a new window on the universe. However, because of the relatively poor angular resolution of these…