Related papers: Machine learning methods for constructing probabil…
The Second Fermi LAT source catalog (Nolan et al. 2012) includes as many as 1,873 sources, but initial attempts to identify counterparts at other wavelengths resulted in 575 sources remaining unidentified. The 2FGL catalog is based on the…
In this paper we discuss an application of machine learning based methods to the identification of candidate AGN from optical survey data and to the automatic classification of AGNs in broad classes. We applied four different machine…
A significant fraction (~30%) of the high-energy gamma-ray sources listed in the second Fermi LAT catalog (2FGL) are still of unknown origin, being not yet associated with counterparts at low energies. We recently developed a new…
We present a new and efficient algorithm for finding point sources in the photon event data stream from the Fermi Gamma-Ray Space Telescope, FermiFAST. The key advantage of FermiFAST is that it constructs a catalogue of potential sources…
The latest source catalog of the Fermi-LAT telescope contains more than 7000 $\gamma$-ray sources at GeV energies, with the two dominant source classes thought to be blazars and rotation-powered pulsars. Our target is the identification of…
The deepest all-sky survey available in the $\gamma$-ray band - the last release of the Fermi-LAT catalogue (4FGL-DR3) based on the data accumulated in 12 years, contains more than 6600 sources. The largest population among the sources is…
Excess of gamma rays with a spherical morphology around the Galactic center (GC) observed in the Fermi large area telescope (LAT) data is one of the most intriguing features in the gamma-ray sky. The excess has been interpreted by…
Building on our previous cross-correlation analysis (Xia et al. 2011) between the isotropic gamma-ray background (IGRB) and different tracers of the large-scale structure of the universe, we update our results using 60-months of data from…
We report our detailed data analysis for 39 $\gamma$-ray sources selected from the 992 unassociated sources in the \textit{Fermi} Large Area Telescope (LAT) third source catalog. The selection criteria, which were set for finding candidate…
The recently published fourth Fermi Large Area Telescope source catalog (4FGL) reports 5065 gamma-ray sources in terms of direct observational gamma-ray properties. Among the sources, the largest population is the Active Galactic Nuclei…
The determination of distance is fundamental in astrophysics. Gamma-ray sources are poorly characterized in this sense, as the limited angular resolution and poor photon-count statistics in gamma-ray astronomy makes it difficult to…
We present the results of an all-sky radio survey between 5 and 9 GHz of the fields surrounding all unassociated gamma-ray objects listed in the Fermi Large Area Telescope Second Source Catalog (2FGL). The goal of these observations is to…
Detection of point sources in images is a fundamental operation in astrophysics, and is crucial for constraining population models of the underlying point sources or characterizing the background emission. Standard techniques fall short in…
We present the results of our analysis devoted to the research of sources emitting in the energy bands surveyed by both the Swift-BAT and the Fermi-LAT telescopes. We cross-correlate the Fermi-LAT 1-year point source catalogue (1FGL) of…
Astrophysical sources are now observed by many different instruments at different wavelengths, from radio to high-energy gamma-rays, with an unprecedented quality. Putting all these data together to form a coherent view, however, is a very…
We cross correlate the Fermi 11 months survey catalogue (1FGL) with the 20 GHz Australia Telescope Compact Array radio survey catalogue (AT20G) composed by 5890 sources at declination <0 deg. Among the 738 Fermi sources distributed in the…
With a decade of gamma-ray data from the Fermi-LAT telescope, we can now hope to answer how well we know the local Universe at gamma-ray frequencies. On the other hand, with gamma-ray data alone it is not possible to directly access the…
In the recently published 3FGL catalogue, the Fermi/LAT collaboration reports the detection of $\gamma$-ray emission from 3034 sources obtained after four years of observations. The nature of 1010 of those sources is unknown, whereas 2023…
The study of machine learning (ML) techniques for the autonomous classification of astrophysical sources is of great interest, and we explore its applications in the context of a multifrequency data-frame. We test the use of supervised ML…
Spatial extension is an important characteristic for correctly associating gamma-ray-emitting sources with their counterparts at other wavelengths and for obtaining an unbiased model of their spectra. We present a new method for quantifying…