Angela Malizia

3C 403 is a well-known FR II radio galaxy with jets extending up to kiloparsec scales. We report its identification as the second most significant candidate among more than 150 sources examined using the 15-year neutrino dataset from the ANTARES collaboration, making it one of the most promising radio-galaxy candidates for high-energy neutrino emission. Motivated by previous associations between blazars and neutrino events, we investigated the jet properties of 3C 403 and their possible role in neutrino production. Multi-scale radio observations, from parsec to kiloparsec scales, reveal a stable, two-sided jet lying close to the plane of the sky, with no evidence of strong Doppler boosting, while X-ray data indicate a dominant, heavily absorbed accretion-related component. We also examined the recently proposed correlation between neutrino and hard X-ray fluxes — originally identified in blazars and Seyfert galaxies — and find that 3C 403 occupies an intermediate location in the L _ν – L _hX plane between jet-dominated and corona-dominated systems. However, the current upper limit on its neutrino flux prevents a firm assessment of whether it follows the proposed relation. With radiatively efficient accretion (λ _Edd ∼ 10 ^-2 ), strong hard X-ray emission, and a powerful but misaligned jet, 3C 403 provides a physically motivated laboratory for exploring the interplay between coronal activity and jet environments in multimessenger scenarios of neutrino production in active galaxies.

The International Gamma-ray Astrophysics Laboratory (INTEGRAL) has been surveying the sky above 20 keV since its launch in 2002 providing new insights into the nature of the sources that populate our Universe at soft gamma-ray energies. The latest IBIS/ISGRI survey lists 929 hard X-ray sources, of which 113 are reported as unidentified, i.e. lacking a lower energy counterpart or simply not studied in other wavebands. To overcome this lack of information, we either browsed the X-ray archives, or, if no data in the X-ray band were available, we requested Target of Opportunity (ToO) observations with the X-ray Telescope (XRT) on-board the Neil Gehrels Swift Observatory. Following this approach, we selected a sample of 10 objects for which X-ray data were key to investigate their nature. We found a single X-ray association for all of the sources, except for IGR J16267-3303, for which two X-ray detections were spotted within the IBIS positional uncertainty. We then browsed multi-waveband archives to search for counterparts to these X-ray detections at other wavelengths and analysed X-ray spectral properties to determine their nature and association with the high-energy emitter. As a result of our analysis, we identified the most likely counterpart for 7 sources, although in some cases its nature/class could not be definitely assessed on the basis of the information collected. Interestingly, SWIFT J2221.6+5952, first reported in the 105-month Swift/Burst Alert Telescope (BAT) survey, is the only source of the sample for which we did not find any counterpart at radio/optical/IR wavebands. Finally, we found that two IBIS source, IGR J17449-3037 and IGR J17596-2315 are positionally associated with a Fermi Large Area Telescope (LAT) object.

We present an analysis of the gas kinematics in NGC 2992 based on VLT/MUSE, ALMA, and VLA data. Our aim is to characterise the disc, the wind, and their interplay in the cold molecular and warm ionised phases. NGC 2992 is a changing-look Seyfert known to host both a nuclear ultrafast outflow (UFO), and an AGN-driven kiloparsec-scale ionised wind. CO(2−1) and Hα arise from a multiphase disc with an inclination of 80 deg and radii of 1.5 and 1.8 kpc, respectively. By modelling the gas kinematics, we find that the velocity dispersion of the cold molecular phase, σ_gas, is consistent with that of star forming galaxies at the same redshift, except in the inner 600 pc region, and in the region between the cone walls and the disc, where σ_gas is a factor of 3−4 larger than in star forming galaxies for both the cold molecular and the warm ionised phases. This suggests that a disc–wind interaction locally boosts the gas turbulence. We detect a clumpy ionised wind in Hβ, [O III], Hα, and [N II] distributed in two wide-opening-angle ionisation cones reaching scales of 7 kpc (40 arcsec). The [O III] wind expands with a velocity exceeding −1000 km s⁻¹ in the inner 600 pc, which is a factor of approximately five greater than the previously reported wind velocity. Based on spatially resolved electron density and ionisation parameter maps, we infer an ionised outflow mass of M_of, ion = (3.2 ± 0.3)×10⁷ M_⊙, and a total ionised outflow rate of Ṁ_of,ion = 13.5 ± 1 M_⊙ yr⁻¹. We detected ten clumps of cold molecular gas located above and below the disc in the ionisation cones, reaching maximum projected distances of 1.7 kpc and showing projected bulk velocities of up to 200 km s⁻¹. On these scales, the wind is multiphase, with a fast ionised component and a slower molecular one, and a total mass of M_{of, ion + mol} = 5.8 × 10⁷ M_⊙, of which the molecular component carries the bulk of the mass, namely M_of, mol = 4.3 × 10⁷ M_⊙. The dusty molecular outflowing clumps and the turbulent ionised gas are located at the edges of the radio bubbles, suggesting that the bubbles interact with the surrounding medium through shocks, as also supported by the [O I]/Hα ratio. Conversely, both the large opening angle and the dynamical timescale of the ionised wind detected in the ionisation cones on 7 kpc scales indicate that this is not related to the radio bubbles but instead likely associated with a previous AGN episode. Finally, we detect a dust reservoir that is co-spatial with the molecular disc, with a cold dust mass of M_dust = (4.04 ± 0.03)×10⁶ M_⊙, which is likely responsible for the extended Fe Kα emission seen on 200 pc scales in hard X-rays and interpreted as reflection by cold dust.

In this work, we analyse three average-luminosity hard X-ray selected AGN: ESO 506-G27, IGR J19039+3344, and NGC 7465. They have simultaneous Swift/XRT and NuSTAR data never published before and have been poorly studied at X-ray energies. These sources make for interesting targets both from a methodological and scientific point of view. Scientifically, they are of interest since they are possibly heavily absorbed objects, belong to a peculiar class and are variable both in flux and in spectral shape. Methodologically, because it is an interesting exercise to understand how existing spectral models can be applied to faint sources and how the use of NuSTAR data alone and then simultaneous and/or average data impacts on the spectral parameters determination. In this work, we demonstrate that simultaneous data are not sufficient if their statistical quality is poor. Moreover, we show that also the use of time-averaged data when dealing with faint AGN does not always provide confident results as for brighter AGN. Regardless of the poor data quality employed in our analysis, we are able to provide insights into the spectral characteristics of each source. We analyse in detail for the first time the iron line complex of ESO 506-G27, finding not only the presence of the iron K α and K β lines, but also of the iron K edge around 7 keV in the NuSTAR data. We also highlight changes in the absorption properties of IGR J19039+3344 and confirm NGC 7465 to be an unabsorbed type 1 LINER.

In this work we have updated the list of active galactic nuclei (AGN) detected by INTEGRAL taking into account the new objects listed in the last published INTEGRAL/IBIS survey. We have collected 83 new AGN, increasing the number of INTEGRAL-detected active galaxies (436) by 19%. Half of these new additions are located behind the Galactic plane, and for most of them we have full X-ray coverage, obtained through archival data from Swift/XRT, XMM-Newton, and NuSTAR. The soft X-ray data allowed us to associate each high-energy emitter with a single or multiple X-ray counterpart(s) and characterise the spectral shape of these new AGN by estimating the photon index, the intrinsic absorption, and the 2–10 keV flux. A few cases where two soft X-ray counterparts fall within the INTEGRAL error circle and at least one is classified as an AGN have been found and discussed in detail. Thirty-four sources originally listed as AGN candidates or unidentified objects have been recognised as AGN by employing three diagnostic tests: WISE colours, radio emission, and morphology. For 12 sources among the 34 AGN candidates, we reduced the optical spectra and confirmed their AGN nature, providing also their optical class and redshift. This paper is part of an ongoing effort to keep the INTEGRAL AGN catalogue updated in order to provide the scientific community with a hard X-ray selected sample of well-classified and spectrally characterised active galaxies.

In this work we have updated the list of AGN detected by INTEGRAL taking into account the new objects listed in the last published INTEGRAL/IBIS survey. We have collected 83 new AGN increasing the number of INTEGRAL detected active galaxies (436) by 19%. Half of these new additions are located behind the Galactic plane; for most of them we have full X-ray coverage obtained through archival data from Swift/XRT, XMM-Newton and NuSTAR. This allowed us to associate each high-energy emitter with a single or multiple X-ray counterpart/s and characterise the spectral shape of these new AGN by estimating the photon index, the intrinsic absorption and the 2-10 keV flux. A few cases where two soft X-ray counterparts fall within the INTEGRAL error circle and at least one is classified as an AGN have been found and discussed in detail. Thirty-four sources originally listed as AGN candidates or unidentified objects have been recognised as AGN by employing three diagnostic tests: WISE colours, radio emission and morphology. For 12 sources, among the 34 AGN candidates, we reduced optical spectra and confirmed their AGN nature, providing also their optical class and redshift. This paper is part of an on-going effort to keep the INTEGRAL AGN catalogue updated in order to provide the scientific community with a hard X-ray selected sample of active galaxies well classified and spectrally characterised.

Many of the new high energy sources discovered both by INTEGRAL/IBIS and Swift/BAT have been characterized thanks to extensive, multiband follow-up campaigns, but there are still objects whose nature remains to be asserted. In this paper, we investigate the true nature of three high energy sources, IGR J12134−6015, IGR J16058−7253, and Swift J2037.2+4151, employing multiwavelength data from the near-infrared to the X-rays. Through Gaia and ESO-VLT measurements and through Swift/XRT X-ray spectral analysis, we re-evaluate the classification for IGR J12134−6015, arguing that the source is a Galactic object and in particular a cataclysmic variable. We were able to confirm, thanks toNuclear Spectroscopic Telescope Array(NuSTAR) observations, that the hard X-ray emission detected by INTEGRAL/IBIS and Swift/BAT from IGR J16058−7253 is coming from two Seyfert 2 galaxies which are both counterparts for this source. Through optical and X-ray spectral analysis of SwiftJ2037.2+4151 we find that this source is likely part of the rare and peculiar class of symbiotic X-ray binaries and displays flux and spectral variability as well as interesting spectral features, such as a blending of several emission lines around the iron line complex.

Investigations that were carried out over the last two decades with novel and more sensitive instrumentation have dramatically improved our knowledge of the more violent physical processes taking place in galactic and extra-galactic Black-Holes, Neutron Stars, Supernova Remnants/Pulsar Wind Nebulae, and other regions of the Universe where relativistic acceleration processes are in place. Simultaneous and/or combined observations with gamma-ray satellites and ground based high-energy telescopes, have clarified the scenario of the mechanisms responsible for high energy photon emission by leptonic and hadronic accelerated particles in the presence of magnetic fields. Specifically, the European Space Agency INTEGRAL soft gamma-ray observatory has detected more than 1000 sources in the soft gamma-ray band, providing accurate positions, light curves and time resolved spectral data for them. Space observations with Fermi-LAT and observations that were carried out from the ground with H.E.S.S., MAGIC, VERITAS, and other telescopes sensitive in the GeV-TeV domain have, at the same time, provided evidence that a substantial fraction of the cosmic sources detected are emitting in the keV to TeV band via Synchrotron-Inverse Compton processes, in particular from stellar galactic BH systems as well as from distant black holes. In this work, employing a spatial cross correlation technique, we compare the INTEGRAL/IBIS and TeV all-sky data in search of secure or likely associations. Although this analysis is based on a subset of the INTEGRAL all-sky observations, we find that there is a significant correlation: 39 objects show emission in both soft gamma-ray and TeV wavebands. The full INTEGRAL database, now comprising almost 19 years of public data available, will represent an important legacy that will be useful for the Cherenkov Telescope Array (CTA) and other ground based large projects.

We present an update on the sample of soft gamma-ray selected giant radio galaxies (GRGs) extracted from INTEGRAL/IBIS and Swift/BAT surveys; it includes eight new sources and one candidate object. In the new sample, all but one source display FR II radio morphologies; the only exception is B21144+35B, which is an FR I. The objects belong to both type 1 and type 2 active galactic nucleus (AGN) optical classes and have redshifts in the range 0.06–0.35, while the radio sizes span from 0.7 to 1 Mpc. In this study, we present for the first time two objects that were never discussed as GRGs before and propose a new candidate GRG. We confirm the correlation between the X-ray luminosity and the radio core luminosity found for other soft gamma-ray selected GRGs and expected for AGNs powered by efficient accretion. We also corroborate previous results that indicate that the luminosity of the radio lobes is relatively low compared with the nuclear X-ray emission. This supports the idea that the nucleus of these GRGs is now more powerful than in the past, consistent with a restarting activity scenario.