247 research outputs found
The XMM-Newton view of the relativistic spectral features in AXJ0447-0627
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
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?
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
Time-course of left ventricle function during mild therapeutic hypothermia in out-of-hospital cardiac arrest patients
Peer reviewe
XR in Aviation Training: Insight from Academia, Industry, and Non-Profit Institutions
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
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
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
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
Prevention and management of dermatologic adverse events associated with Tumor Treating Fields in patients with glioblastoma
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