Related papers: Investigating source confusion in PMN J1603$-$4904
We present high spatial resolution MERLIN 1.4GHz radio observations of two high redshift (z~2) sources, RGJ123623 (HDF147) and RGJ123617 (HDF130), selected as the brightest radio sources from a sample of submillimetre-faint radio galaxies.…
For the duration of the Fermi Gamma-Ray Space Telescope's mission, approximately one-third of the point sources detected have been noted as "unassociated," meaning that they seem to have no known counterpart at any other…
Low-luminosity Active Galactic Nuclei (LLAGN) represent a unique class of AGN in the local universe. Extensive studies of these objects are essential for a comprehensive understanding of jet physics, as past research has largely focused on…
We present very long baseline interferometry (VLBI) observations of 179 radio sources in the COSMOS field with extremely high sensitivity using the Green Bank Telescope (GBT) together with the Very Long Baseline Array (VLBA) (VLBA+GBT) at…
Many sources in the fourth INTEGRAL/IBIS catalogue are still unidentified, since they lack an optical counterpart. An important tool that can help in identifying/classifying these sources is the cross-correlation with radio catalogues,…
We aim to spectroscopically confirm the nature of VVV-J181258.71-314346.7, a candidate counterpart to the unassociated gamma-ray source 4FGLJ1812.8-3144. This object was selected based on its near-infrared photometric properties and…
We apply a number of statistical and machine learning techniques to classify and rank gamma-ray sources from the Third Fermi Large Area Telescope (LAT) Source Catalog (3FGL), according to their likelihood of falling into the two major…
We report on a new method to identify Active Galactic Nuclei (AGN) among unidentified INTEGRAL sources. This method consists of cross-correlating unidentified sources listed in the fourth IBIS Survey Catalogue first with infrared and then…
PKS J2310-437 is an AGN with bright X-ray emission relative to its weak radio emission and optical continuum. It is believed that its jet lies far enough from the line of sight that it is not highly relativistically beamed. It thus provides…
A 10-arcmin field around the HDF(N) contains 92 radio sources >40 uJy, resolved by MERLIN+VLA at 0".2-2".0 resolution. 55 have Chandra X-ray counterparts including 18 with a hard X-ray photon index and high luminosity characteristic of a…
Machine learning has emerged as a powerful tool in the field of gamma-ray astrophysics. The algorithms can distinguish between different source types, such as blazars and pulsars, and help uncover new insights into the high-energy universe.…
In 8 years of operation, the Large Area Telescope (LAT) on the Fermi satellite has impacted our understanding of gamma-ray pulsars dramatically. The LAT now sees over two hundred pulsars: the largest class of GeV sources in the Milky Way.…
In search of the counterpart to the brightest unidentified gamma-ray source 3EG J2020+4017 we report on new X-ray and radio observations of the gamma-Cygni field with the Chandra X-ray Observatory and with the Green Bank Telescope. We also…
The Fermi Large Area Telescope First Source Catalog (1FGL) provided spatial, spectral, and temporal properties for a large number of gamma-ray sources using a uniform analysis method. After correlating with the most-complete catalogs of…
Variable gamma-ray emission has been discovered in five Radio-loud Narrow Line Seyfert 1 (NLSy1) galaxies by the Large Area Telescope (LAT) onboard the Fermi Gamma-Ray Space Telescope. This has clearly demonstrated that these NLSy1 galaxies…
We present a new method to interpret the $\gamma$-ray data of our inner Galaxy as measured by the Fermi Large Area Telescope (Fermi LAT). We train and test convolutional neural networks with simulated Fermi-LAT images based on models tuned…
Submillimetre-selected galaxies (SMGs) at high redshift ($z$ $\sim$ 2) are potential host galaxies of active galactic nuclei (AGN). If the local Universe is a good guide, $\sim$ 50$\%$ of the obscured AGN amongst the SMG population could be…
We present a statistical characterization of the $\gamma$-ray emission from the four \emph{Fermi}-LAT sources: FR I radio galaxy NGC 1275, BL Lac Mrk 421, FSRQs B2 1520+31 and PKS 1510-089 detected almost continuously over a time…
Recent studies have found a positive correlation between the star-formation rate of galaxies and their gamma-ray luminosity. Galaxies with a high star-formation rate are expected to produce a large amount of high-energy cosmic rays, which…
3C 84 is a nearby Active Galactic Nucleus (AGN) that is unique in that is believed that we are observing near the true jet launching region - unlike blazars. The source is active in Gamma rays and has been detected with Fermi since its…