We present the spectral and timing analysis of X-ray observations performed on the Galactic black hole transient GRS 1716-249 during the 2016-2017 outburst. The source was almost continuously observed with the Neil Gehrels Swift Observatory from December 2016 until October 2017. The X-ray hardness ratio and timing evolution indicate that the source approached the soft state three times during the outburst, even though it never reached the canonical soft spectral state. Thus, GRS 1716-249 increases the number of black hole transients showing outbursts with "failed" state transition. During the softening events, XRT and BAT broadband spectral modeling, performed with thermal Comptonization plus a multicolor disc black-body, showed a photon index (Γ < 2) and an inner disc temperature (kT in = 0.2-0.5 keV) characteristic of the hard intermediate state. This is in agreement with the root mean square amplitude of the flux variability (rms > 10%). We find that, coherently with a scenario in which the disc moves closer to the compact object, the accretion disc inner radius decreases with the increase of the inner disc temperature, until a certain point when the temperature starts to increase at constant radius. This, in addition with the spectral analysis results, suggests that either the accretion disc reached the innermost stable circular orbit during the hard intermediate state or the hot accretion flow might re-condensate in an inner mini-disc. We report on the radio observations performed during the outburst finding that GRS 1716-249 is located on the radio-quiet "outlier" branch of the radio/X-ray luminosity plane.

The black hole transient GRS 1716−249 was monitored from the radio to the γ-ray band during its 2016–2017 outburst. This paper focuses on the spectral energy distribution (SED) obtained in 2017 February–March, when GRS 1716−249 was in a bright hard spectral state. The soft γ-ray data collected with the INTEGRAL/SPI telescope show the presence of a spectral component that is in excess of the thermal Comptonization emission. This component is usually interpreted as inverse Compton emission from a tiny fraction of non-thermal electrons in the X-ray corona. We find that hybrid thermal/non-thermal Comptonization models provide a good fit to the X-/γ-ray spectrum of GRS 1716−249. The best-fitting parameters are typical of the bright hard state spectra observed in other black hole X-ray binaries. Moreover, the magnetized hybrid Comptonization model belm provides an upper limit on the intensity of the coronal magnetic field of about 106 G. Alternatively, this soft γ-ray emission could originate from synchrotron emission in the radio jet. In order to test this hypothesis, we fit the SED with the irradiated disc plus Comptonization model combined with the jet internal shock emission model ishem. We found that a jet with an electron distribution of p ≃ 2.1 can reproduce the soft γ-ray emission of GRS 1716−249. However, if we introduce the expected cooling break around 10 keV, the jet model can no longer explain the observed soft γ-ray emission, unless the index of the electron energy distribution is significantly harder (p &lt; 2).

We present a multi-wavelength study of IC 1531 (z=0.02564), an extragalactic radio source associated with the γ-ray object 3FGL J0009.9−3206 and classified as a blazar of uncertain type in the Third Fermi Large Area Telescope AGN Catalog (3LAC). A core-jet structure, visible in radio and X-rays, is enclosed within a ∼220 kpc wide radio structure. The morphology and spectral characteristics of the kiloparsec jet in radio and X-rays are typical of Fanaroff-Riley type I galaxies. The analysis of the radio data and optical spectrum and different diagnostic methods based on the optical, infrared and γ-ray luminosities also support a classification as a low-power radio galaxy seen at moderate angles (θ =10 • -20 • ). In the framework of leptonic models, the high-energy peak of the non-thermal nuclear spectral energy distribution can be explained in terms of synchrotron-self-Compton emission from a jet seen at θ ∼15 • . Similarly to other misaligned AGNs detected by Fermi, the required bulk motion is lower (Γ bulk =4) than the values inferred in BL Lac objects, confirming that, because of the de-boosting of emission from the highly-relativistic blazar region, these nearby systems are valuable targets to probe the existence of multiple sites of production of the most energetic emission in the jets.

Context. The X-ray transient eclipsing source MXB 1659-298 went in outburst in 1999 and 2015, respectively. During these two outbursts the source was observed by XMM-Newton, NuSTAR and Swift/XRT . Aims. Using these observations we studied the broadband spectrum of the source to constrain the continuum components and to verify the presence of a reflection component as recently observed in the X-ray eclipsing transient source AX J1745.6-2901. Methods. We combined the available spectra studying the soft and hard state of the source in the 0.4-35 keV and 0.45-55 keV energy range, respectively. Results. We find that the soft state can be modelled with a thermal component associated with the inner accretion disk plus a Comptonized component. A broad emission line at 6.6 keV and narrow absorption lines associated with highly ionized ions of oxygen, neon and iron are observed. We obtain a best-fit model using a smeared reflection component that fits a reflection emission from the innermost region of the system and adding a component that takes into account the ionized absorber where the narrow absorption lines forms. The equivalent hydrogen column density associated with the absorber is close to 6 × 10 23 cm −2 . On the other hand, the direct continuum emission in the hard state can be described by a comptonized component with a temperature larger than 150 keV. Also in this state a reflection component and a ionized absorber are observed. The equivalent hydrogen column density associated with the absorber is close to 1.3 × 10 23 cm −2 .

The X-ray transient eclipsing source MXB 1659-298 went in outburst in 1999 and 2015, respectively, during which it was observed by XMM-Newton, NuSTAR and Swift. Using these observations we studied the broadband spectrum of the source to constrain the continuum components and to verify the presence of a reflection component. We analysed the soft and hard state of the source, finding that the soft state can be modelled with a thermal component associated with the inner accretion disc plus a Comptonised component. A smeared reflection component and the presence of an ionised absorber are also requested in the best-fit model. On the other hand, the direct continuum emission in the hard state can be described by a Comptonised component with a temperature larger than 150 keV. Also in this case a reflection component and a ionised absorber are observed.

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