相关论文: Mining the Blazar Sky

The Fermi Large Area Telescope (LAT) is currently the most important facility for investigating the GeV $\gamma$-ray sky. With Fermi LAT more than three thousand $\gamma$-ray sources have been discovered so far. 1144 ($\sim40\%$) of the…

We present Bayesian Binary Search (BBS), a novel probabilistic variant of the classical binary search/bisection algorithm. BBS leverages machine learning/statistical techniques to estimate the probability density of the search space and…

Current and future astronomical surveys are producing catalogs with millions and billions of objects. On-line access to such big datasets for data mining and cross-correlation is usually as highly desired as unfeasible. Providing these…

In this paper we discuss various possibilities of using X-ray observations to gain information about the large-scale structure of the Universe. After reviewing briefly the current status of these investigations we explore different ways of…

We describe a new and efficient technique which we call sideband or phase-modulation searching that allows one to detect short period binary pulsars in observations longer than the orbital period. The orbital motion of the pulsar during…

In this paper we propose a way to use optical polarisation observations to provide independent constraints and guide to the modelling of the spectral energy distribution (SED) of blazars, which is particularly useful when two-zone models…

Astronomy is undergoing through a methodological revolution triggered by an unprecedented wealth of complex and accurate data. The new panchromatic, synoptic sky surveys require advanced tools for discovering patterns and trends hidden…

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 Fermi, Swift and INTEGRAL satellites, together with ground based (especially Cherenkov) telescopes made possible a great progress in our understanding of relativistic jets. We can now start to attack the difficult questions of jet…

Using archival X-ray data from the second XMM-Newton serendipitous source catalogue, we present comparative analysis of the overall population of X-ray sources in the Large and Small Magellanic Clouds. We see a difference between the…

In an earlier paper we presented nuclear X-ray flux densities, measured with ROSAT, for the B2 bright sample of nearby low-luminosity radio galaxies. In this paper we construct a nuclear X-ray luminosity function for the B2 radio galaxies,…

Aims. The observation of gamma -ray flares from blazar 0836+710 in 2011, following a period of quiescence, offered an opportunity to study correlated activity at different wavelengths for a high-redshift (z=2.218) active galactic nucleus.…

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…

Blazars are highly variable active galactic nuclei which emit radiation at all wavelengths from radio to gamma-rays. Polarized radiation from blazars is one key piece of evidence for synchrotron radiation at low energies and it also varies…

We present a catalog of cross-correlated radio, infrared and X-ray sources using a very restrictive selection criteria with an IDL-based code developed by us. The significance of the observed coincidences was evaluated through Monte Carlo…

BL Lac objects are an elusive and rare class of active galactic nuclei. For years their evolutionary behavior has appeared inconsistent with the trend observed in the population of AGN at large. The so-called ``negative'' evolution implies…

Over half the 3CRR sample of radio galaxies and quasars has been observed in X-rays with ROSAT pointed observations, and we present results from these observations, discussing many of the sources in detail. The improved spatial resolution…

Large digital sky surveys, over a broad range of wavelengths, both from the ground and from space observatories, are becoming a major source of astronomical data. Some examples include the Sloan Digital Sky Survey (SDSS) and the Digital…

We have modelled the spatial distribution of luminous X-ray binaries (XRBs) in spiral galaxies that are like the Milky Way using an evolutionary population synthesis code. In agreement with previous theoretical expectations and…

We first review some basic properties of the most important classes of active galactic nuclei (AGN), including quasars, blazars, Seyfert galaxies and radio galaxies. The most commonly accepted type of scheme designed to individually unify…