247 research outputs found

    The XMM-Newton view of the relativistic spectral features in AXJ0447-0627

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    The XMM-Newton observation of the optically Type 1 AGN AXJ0447-0627 (z=0.214) unambiguously reveals a complex, bright and prominent set of lines in the 4-8 keV rest frame energy range. Although, from a phenomenological point of view, the observed properties can be described by a simple power law model plus 5 narrow Gaussian lines (at rest frame energies of nearly 4.49, 5.55, 6.39, 7.02 and 7.85 keV), we find that a model comprising a power law (Gamma of the order of 2.2), a reflected relativistic continuum, a narrow Fe I Kalpha line from neutral material as well as a broad Fe Kalpha relativistic line from a ionized accretion disk represents a good physical description of the data. The ''double horned'' profile of the relativistic line implies an inclination of the accretion disk of the order of 45 degree, and an origin in a narrow region of the disk, from R_in of the order of 19 GM/c^2 to R_out of the order of 30 GM/c^2. The narrow Fe I Kalpha line from neutral material is probably produced far from the central black hole, most likely in the putative molecular torus. Although some of these properties have been already found in other Type 1 AGN and discussed in the literature, at odd with the objects reported so far we measure high equivalent widths (EWs) of the observed lines: nearly 1.4 keV for the ``double horned'' relativistic line and nearly 0.4 keV for the narrow line.Comment: 16 pages, 3 figures, Latex manuscript; accepted for publication in Ap

    WISE colours and star-formation in the host galaxies of radio-loud narrow-line Seyfert 1

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    We investigate the mid-infrared properties of the largest (42 objects) sample of radio-loud narrow-line Seyfert 1 (RL NLS1) collected to date, using data from the Wide-field Infrared Survey Explorer (WISE). We analyse the mid-IR colours of these objects and compare them to what is expected from different combinations of AGN and galaxy templates. We find that, in general, the host-galaxy emission gives an importan contribution to the observed mid-IR flux in particular at the longest wavelengths (W3, at 12micron, and W4, at 22micron). In about half of the sources (22 objects) we observe a very red mid-IR colour (W4-W3>2.5) that can be explained only using a starburst galaxy template (M82). Using the 22micron luminosities, corrected for the AGN contribution, we have then estimated the star-formation rate for 20 of these "red" RL NLS1, finding values ranging from 10 to 500 Msun/y. For the RL NLS1 showing bluer colours, instead, we cannot exclude the presence of a star-forming host galaxy although, on average, we expect a lower star-formation rate. Studying the radio (1.4GHz) to mid-IR (22micron) flux ratios of the RL NLS1 in the sample we found that in ~10 objects the star-forming activity could represent the most important component also at radio frequencies, in addition (or in alternative) to the relativistic jet. We conclude that both the mid-IR and the radio emission of RL NLS1 are a mixture of different components, including the relativistic jet, the dusty torus and an intense star-forming activity.Comment: Accepted for publication in MNRAS, 11 pages, 7 figures, 2 table

    SDSSJ143244.91+301435.3: a link between radio-loud narrow-line Seyfert 1 galaxies and compact steep-spectrum radio sources?

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    We present SDSSJ143244.91+301435.3, a new case of radio-loud narrow line Seyfert 1 (RL NLS1) with a relatively high radio power (P1.4GHz=2.1x10^25 W Hz^-1) and large radioloudness parameter (R1.4=600+/-100). The radio source is compact with a linear size below ~1.4 kpc but, contrary to most of the RL NLS1 discovered so far with such a high R1.4, its radio spectrum is very steep (alpha=0.93) and not supporting a 'blazar-like' nature. Both the small mass of the central super-massive black-hole and the high accretion rate relative to the Eddington limit estimated for this object (3.2x10^7 Msun and 0.27, respectively, with a formal error of ~0.4 dex on both quantities) are typical of the class of NLS1. Through a modeling of the spectral energy distribution of the source we have found that the galaxy hosting SDSSJ143244.91+301435.3 is undergoing a quite intense star-formation (SFR=50 Msun y^-1) which, however, is expected to contribute only marginally (~1 per cent) to the observed radio emission. The radio properties of SDSSJ143244.91+301435.3 are remarkably similar to those of compact steep spectrum (CSS) radio sources, a class of AGN mostly composed by young radio galaxies. This may suggest a direct link between these two classes of AGN, with the CSS sources possibly representing the misaligned version (the so-called parent population) of RL NLS1 showing blazar characteristics.Comment: 14 pages, 7 figures, 4 tables, accepted for publication in MNRA

    XR in Aviation Training: Insight from Academia, Industry, and Non-Profit Institutions

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    The COVID-19 pandemic had a profound impact on education and training. Institutions that relied heavily on face-to-face instruction suddenly needed alternative modalities to keep students on course, forcing educators and trainers to employ a variety of educational techniques via technologies that they may not have had experience with. This shift has brought the advantages – and disadvantages – of augmented, mixed, and virtual reality technologies (collectively, extended reality or XR) for education and training into sharp focus. Programs were quickly assembled, and not always with consideration of learning theories. As learning and training were resumed in in-person settings, academics and industry alike were faced with a new challenge: How do we continue to develop XR technologies to leverage efficiencies and expand opportunities without sacrificing learning and training outcomes? This question has brought researchers, practitioners, developers, and innovators together into an XR Research Consortium to advocate for the design, evaluation, implementation, and sharing of findings of XR technology in a variety of learning and training environments. Although many of the members have a background in aviation and aerospace, a goal of the Consortium is to expand into other industries and promote XR technologies as educational tools. Members of the Consortium will discuss: Current research, gaps in the research, potential for XR Using XR to make learning/training more accessible Choosing an XR technology that aligns with learning/training outcomes Cybersecurity considerations of XR in a learning/training environment Demonstrations of XR applications for training will be included. The session will include time for an open discussion

    The radio core and jet in the broad absorption line quasar PG 1700+518

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    The blue-shifted broad absorption lines (BAL) or troughs are observed in Active Galactic Nuclei (AGNs) when our line of sight is intercepted by a high speed outflow (wind), likely originating in the accretion disc. The outflow or wind can shed light on the internal structure obscured by the AGN torus. Recently, it has been shown that this outflow is rotating in the BAL quasar PG 1700+518, further supporting the accretion disc origin of the wind. With the purpose of giving independent constraints on the wind geometry, we performed high-resolution European VLBI Network (EVN) observations at 1.6 GHz in 2010. Combining the VLBI (Very Long Baseline Interferometry) results with the Very Large Array (VLA) archival data at 8.4 GHz, we present its jet structure on scales of parsec (pc) to kiloparsec (kpc) for the first time. The source shows two distinct jet features in East-West direction with a separation of around 4 kpc. The Eastern feature, which has so far been assumed to hide the core, is a kpc-scale hot spot, which is completely resolved out in the EVN image. In the western jet feature, we find a compact jet component, which pinpoints the position of the central black hole in the galaxy. Jet components on both sides of the core are additionally detected in the Northwest-Southeast direction, and they show a symmetric morphology on scale of <1 kpc. This two-sided jet feature is not common in the known BAL quasars and indicates that the jet axis is far away from the line of sight. Furthermore, it is nearly parallel to the scattering plane revealed earlier by optical polarimetry. By analogy to polar-scattered Seyfert 1 galaxies, we conclude that the jet likely has a viewing angle around 45 degree. The analogy is further supported by the recent report of significant cold absorption in the soft X-rays, a nearly unique feature to polar-scattered Seyfert galaxies.Comment: Accepted for publication in MNRAS Letters, 5 pages, 1 figure

    A new powerful and highly variable disk wind in an AGN-star forming galaxy, the case of MCG-03-58-007

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    We present the discovery of a new candidate for a fast disk wind, in the nearby Seyfert 2 galaxy MCG-03-58-007. This wind is discovered in a deep Suzaku observation that was performed in 2010. Overall the X-ray spectrum of MCG-03-58-007 is highly absorbed by a neutral column density of NH~10^23 cm^-2, in agreement with the optical classification as a type 2 AGN. In addition, this observation unveiled the presence of two deep absorption troughs at E = 7.4 +- 0.1 keV and E = 8.5 +- 0.2 keV. If associated with blue-shifted FeXXVI, these features can be explained with the presence of two highly ionised (log \xi/(erg cm/s)~ 5.5) and high column density (NH~5-8 x 10^23cm^-2) outflowing absorbers with v_out1~ -0.1c and v_out2~ -0.2c. The disk wind detected during this observation is most likely launched from within a few hundreds gravitational radii from the central black and has a kinetic output that matches the prescription for significant feedback. The presence of the lower velocity component of the disk wind is independently confirmed by the analysis of a follow-up XMM-Newton & NuSTAR observation. A faster (v_out~ -0.35 c) component of the wind is also seen in this second observation. During this observation we also witnessed an occultation event lasting \Delta t ~ 120 ksec, which we ascribe to an increase of the opacity of the disk wind (\Delta NH~1.4x10^24 cm^-2). Our interpretation is that the slow zone (v_out~ -0.1c) of the wind is the most stable but inhomogeneous component, while the faster zones could be associated with two different inner streamlines of the wind.Comment: 12 pages, 10 figures, 3 tables. Accepted for publication in MNRA

    1H0707-495 in 2011: An X-ray source within a gravitational radius of the event horizon

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    The Narrow Line Seyfert 1 Galaxy 1H0707-495 went in to a low state from 2010 December to 2011 February, discovered by a monitoring campaign using the X-Ray Telescope on the Swift satellite. We triggered a 100 ks XMM-Newton observation of the source in 2011 January, revealing the source to have dropped by a factor of ten in the soft band, below 1 keV, and a factor of 2 at 5 keV, compared with a long observation in 2008. The sharp spectral drop in the source usually seen around 7 keV now extends to lower energies, below 6 keV in our frame. The 2011 spectrum is well fit by a relativistically-blurred reflection spectrum similar to that which fits the 2008 data, except that the emission is now concentrated solely to the central part of the accretion disc. The irradiating source must lie within 1 gravitational radius of the event horizon of the black hole, which spins rapidly. Alternative models are briefly considered but none has any simple physical interpretation.Comment: 9 pages, 19 figures, MNRAS in pres
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