Related papers: Swift observations of IBL and LBL objects

Extreme high-frequency peaked BL Lac objects (EHBLs) are blazars which exhibit extremely energetic synchrotron emission. They also feature non-thermal gamma-ray emission whose peak lies in the very high-energy (VHE, E > 100 GeV) range, and…

We present the analysis of archival data from ROSAT and ASCA of a serendipitous source PKS 2316-423. According to its featureless non-thermal radio/optical continuum, the object has been assumed as a BL Lac candidate in the literature. It…

Through an optical campaign performed at the San Pedro Martir (Mexico) Telescope and using the 6dF archive (http://www.aao.gov.au/local/www/6df, Jones et al. 2004), we determine or give a better classification for 8 newly discovered Active…

Aims: Active Galactic Nuclei are known to be variable throughout the electromagnetic spectrum. An energy domain poorly studied in this respect is the hard X-ray range above 20 keV. Methods: The first 9 months of the Swift/BAT all-sky survey…

IGR J16195-4945 is a hard X-ray source discovered by INTEGRAL during the Core Program observations performed in 2003. We analyzed the X-ray emission of this source exploiting the Swift-BAT survey data from December 2004 to March 2015, and…

We present a comprehensive 20-year multiwavelength variability study of the blazar PKS 2155-304, one of the most luminous and extensively monitored high-frequency-peaked BL Lac objects in the southern hemisphere. Using Fermi-LAT…

We report on Suzaku observations of four unidentified sources from the INTEGRAL and Swift BAT Galactic plane surveys. All the sources have a large neutral hydrogen column density and are likely members of an emerging class of heavily…

As a radio-loud narrow-line Seyfert 1 galaxy (NLS1) detected by Fermi/LAT in GeV $\gamma$-rays, 1H 0323+342 is a remarkable Active Galactic Nucleus (AGN) showing properties characteristic of both NLS1s and blazars. Here we present results…

(Abridged) Since its launch in October 2002, the INTEGRAL satellite has revolutionized our knowledge of the hard X-ray sky thanks to its unprecedented imaging capabilities and source detection positional accuracy above 20 keV. Nevertheless,…

Analysis of INTEGRAL Core Program and public Open Time observations performed up to April 2005 provides a sample of 62 active galactic nuclei in the 20-100 keV band above a flux limit of ~1.5x10^-11 erg/cm2/s. Most(42) of the sources in the…

We systematically investigate the near- (NIR) to far-infrared (FIR) photometric properties of a nearly complete sample of local active galactic nuclei (AGN) detected in the Swift/Burst Alert Telescope (BAT) all-sky ultra hard X-ray (14-195…

We present the X-ray analysis of the most luminous obscured active galactic nuclei (AGN) inside local ultraluminous infrared galaxies (ULIRGs). Our sample consists of ten sources, harbouring AGN components with estimated luminosity in…

We present the first analysis of the all-sky Swift BAT ultra hard X-ray (14-195 keV) data for a targeted list of objects. We find the BAT data can be studied at 3x fainter limits than in previous blind detection catalogs based on prior…

The SWIFT gamma ray observatory's Burst Alert Telescope (BAT) has detected a sample of active galactic nuclei (AGN) based solely on their hard X-ray flux (14-195 keV). In this paper, we present for the first time {\it XMM-Newton} X-ray…

In this work we present the most comprehensive INTEGRAL AGN sample which lists 272 objects. Here we mainly use this sample to study the absorption properties of active galaxies, to probe new AGN classes and to test the AGN unification…

We report the finding of four changing-look (CL) active galactic nuclei (AGN). We selected these sources due to their potential as interesting targets when considering their relatively-large optical flux variations and related mid-infrared…

The blazar PKS0537-441 has been observed by Swift between the end of 2004 and November 2005. The BAT monitored it recurrently for a total of 2.7 Ms, and the XRT and UVOT pointed it on seven occasions for a total of 67 ks, making it one of…

Extragalactic nuclear activity is best explored with observations at high energies, where the most extreme flux and spectral variations are expected to occur, witnessing changes in the accretion flow or in the kinematics of the plasma. In…

We present a sample of twenty-one ROSAT bright active galactic nuclei (AGN), representing a range of spectral classes, and selected for follow-up snap-shot observations with XMM-Newton. The typical exposure was between 5-10 ks. The objects…

We present the results of our optical identifications of several hard X-ray sources from the INTEGRAL all-sky survey obtained over 14 years of observations. Having improved the positions of these objects in the sky with the X-ray telescope…