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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. [ABSTRACT FROM AUTHOR]

Context. High-resolution X-ray spectroscopy has advanced our understanding of the hot Universe by revealing physical properties like kinematics, temperature, and abundances of the astrophysical plasmas. Despite technical and scientific achievements, the lack of scientific products at a level higher than count spectra is hampering complete scientific exploitation of high-quality data. This paper introduces the Catalog of Ionized Emission Lines Observed by the Reflection Grating Spectrometer (CIELO-RGS) onboard the XMM-Newton space observatory. Aims. The CIELO-RGS catalog aims to facilitate the exploitation of emission features in the public RGS spectra archive. In particular, we aim to analyze the relationship between X-ray spectral diagnostics parameters and measurements at other wavelengths. This paper focuses on the methodology of catalog generation, describing the automated line-detection algorithm. Methods. A moderate sample (∼2400 observations) of high-quality RGS spectra available at XMM-Newton Science Archive is used as our starting point. A list of potential emission lines is selected based on a multi-scale peak-detection algorithm in a uniform and automated way without prior assumption on the underlying astrophysical model. The candidate line list is validated via spectral fitting with simple continuum and line profile models. We also compare the catalog content with published literature results on a small number of exemplary sources. Results. We generate a catalog of emission lines (1.2 × 104) detected in ∼1600 observations toward stars, X-ray binaries, supernovae remnants, active galactic nuclei, and groups and clusters of galaxies. For each line, we report the observed wavelength, broadening, energy and photon flux, equivalent width, and so on. [ABSTRACT FROM AUTHOR]

Context. Large-amplitude, longitudinal filament oscillations triggered by solar flares have been well established in the literature. However, filament oscillations enhanced by flares have never been reported. Aims. In this paper we report the multiwavelength observations of a very long filament in active region (AR) 11112 on 2010 October 18. The filament was composed of two parts, the eastern part (EP) and the western part (WP). We focus on longitudinal oscillations of the EP, which were enhanced by two homologous C-class flares in the same AR. Methods. The filament was observed in Hff wavelength by the Global Oscillation Network Group and in extreme ultraviolet wavelengths by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory (SDO). Line-of-sight magnetograms were provided by the Helioseismic and Magnetic Imager on board SDO. The global three-dimensional magnetic fields were obtained using the potential field source surface modeling. Soft X-ray light curves of the two flares were recorded by the GOES spacecraft. White light images of the corona were observed by the LASCO/C2 coronagraph on board SOHO. To reproduce part of the observations, we perform one-dimensional, hydrodynamic numerical simulations using the MPI-AMRVAC code. Results. The C1.3 flare was confined without a coronal mass ejection (CME). Both EP and WP of the filament were slightly disturbed and survived the flare. After 5 h, eruption of the WP generated a C2.6 flare and a narrow jet-like CME. Three oscillating threads (thda, thdb, thdc) are obviously identified in the EP, and their oscillations are naturally divided into three phases by the two flares. The initial amplitude ranges from 1.6 to 30Mm with a mean value of ~14 Mm. The period ranges from 34 to 73 min with a mean value of ~53 min. The curvature radii of the magnetic dips are estimated to be 29 to 133Mm with a mean value of ~74 Mm. The damping times ranges from ~62 to ~96 min with a mean value of ~82 min. The value of =P is between 1.2 and 1.8. For thda in the EP, the amplitudes were enhanced by the two flares from 6.1Mm to 6.8Mm after the C1.3 flare, and further to 21.4Mm after the C2.6 flare. The period variation as a result of perturbation from the flares was within 20%. The attenuation became faster after the C2.6 flare. Conclusions. To the best of our knowledge, this is the first report of large-amplitude, longitudinal filament oscillations enhanced by flares. Numerical simulations reproduce the oscillations of thda very well. The simulated amplitudes and periods are close to the observed values, while the damping time in the last phase is longer, implying additional mechanisms should be taken into account apart from radiative loss. [ABSTRACT FROM AUTHOR]

Context. Pre-main sequence stars are variable sources. The main mechanisms responsible for their variability are variable extinction, unsteady accretion, and rotational modulation of both hot and dark photospheric spots and X-ray-active regions. In stars with disks, this variability is related to the morphology of the inner circumstellar region (≤0.1AU) and that of the photosphere and corona, all impossible to be spatially resolved with present-day techniques. This has been the main motivation for the Coordinated Synoptic Investigation of NGC 2264, a set of simultaneous observations of NGC 2264 with 15 different telescopes. Aims. In this paper, we focus on the stars with disks. We analyze the X-ray spectral properties extracted during optical bursts and dips in order to unveil the nature of these phenomena. Stars without disks are studied in a companion paper. Methods. We analyze simultaneous CoRoT and Chandra/ACIS-I observations to search for coherent optical and X-ray flux variability in stars with disks. Then, stars are analyzed in two different samples. In stars with variable extinction, we look for a simultaneous increase of optical extinction and X-ray absorption during the optical dips; in stars with accretion bursts, we search for soft X-ray emission and increasing X-ray absorption during the bursts. Results. We find evidence for coherent optical and X-ray flux variability among the stars with variable extinction. In 9 of the 24 stars with optical dips, we observe a simultaneous increase of X-ray absorption and optical extinction. In seven dips, it is possible to calculate the NH/AVV ratio in order to infer the composition of the obscuring material. In 5 of the 20 stars with optical accretion bursts, we observe increasing soft X-ray emission during the bursts that we associate to the emission of accreting gas. It is not surprising that these properties are not observed in all the stars with dips and bursts, since favorable geometric configurations are required. Conclusions. The observed variable absorption during the dips is mainly due to dust-free material in accretion streams. In stars with accretion bursts, we observe, on average, a larger soft X-ray spectral component not observed in non-accreting stars. [ABSTRACT FROM AUTHOR]

Two-thirds of long duration gamma-ray bursts (GRBs) show soft X-ray absorption in excess of the Milky Way. The column densities of metals inferred from UV and optical spectra differ from those derived from soft X-ray spectra, at times by an order of magnitude, with the latter being higher. The origin of the soft X-ray absorption excess observed in GRB X-ray afterglow spectra remains a heavily debated issue, which has resulted in numerous investigations on the effect of hot material both internal and external to the GRB host galaxy on our X-ray afterglow observations. Nevertheless, all models proposed so far have either only been able to account for a subset of our observations (i.e. at z > 2), or they have required fairly extreme conditions to be present within the absorbing material. In this paper, we investigate the absorption of the GRB afterglow by a collisionally ionised and turbulent interstellar medium (ISM). We find that a dense (3 cm-3) collisionally ionised ISM could produce UV/optical and soft X-ray absorbing column densities that differ by a factor of 10. However the UV/optical and soft X-ray absorbing column densities for such sightlines are 2-3 orders of magnitude lower in comparison to the GRB afterglow spectra. For those GRBs with a larger soft X-ray excess by up to an order of magnitude, the contribution in absorption from a turbulent ISM as considered here would ease the required conditions of additional absorbing components, such as the GRB circumburst medium and intergalactic medium. [ABSTRACT FROM AUTHOR]