311 research outputs found
The properties of the clumpy torus and BLR in the polar-scattered Seyfert 1 galaxy ESO 323-G77 through X-ray absorption variability
We report results from multi-epoch X-ray observations of the polar-scattered
Seyfert 1 galaxy ESO 323-G77. The source exhibits remarkable spectral
variability from months to years timescales. The observed spectral variability
is entirely due to variations of the column density of a neutral absorber
towards the intrinsic nuclear continuum. The column density is generally
Compton-thin ranging from a few times 10 cm to a few times
10 cm. However, one observation reveals a Compton-thick state
with column density of the order of 1.5 10 cm. The
observed variability offers a rare opportunity to study the properties of the
X-ray absorber(s) in an active galaxy. We identify variable X-ray absorption
from two different components, namely (i) a clumpy torus whose individual
clumps have a density of 1.7 10 cm and an average
column density of 4 10 cm, and (ii) the broad
line region (BLR), comprising individual clouds with density of 0.1-8
10 cm and column density of 10-10 cm. The
derived properties of the clumpy torus can also be used to estimate the torus
half-opening angle, which is of the order of 47 . We also confirm the
previously reported detection of two highly ionized warm absorbers with outflow
velocities of 1000-4000 km s. The observed outflow velocities are
consistent with the Keplerian/escape velocity at the BLR. Hence, the warm
absorbers may be tentatively identified with the warm/hot inter-cloud medium
which ensures that the BLR clouds are in pressure equilibrium with their
surroundings. The BLR line-emitting clouds may well be the cold, dense clumps
of this outflow, whose warm/hot phase is likely more homogeneous, as suggested
by the lack of strong variability of the warm absorber(s) properties during our
monitoring.Comment: 15 pages, 4 tables, and 9 figures. Accepted for publication in MNRA
High resolution X-ray spectroscopy of the Seyfert 1 Mrk841: insights into the warm absorber and warm emitter
The Seyfert 1 galaxy Mrk841 was observed five times between 2001 and 2005 by
the XMM-Newton X-ray observatory. The source is well known for showing spectral
complexity in the variable iron line and in the soft X-ray excess. This paper
reports on the first study of Mrk841 soft X-ray spectrum at high spectral
resolution. The availability of multiple exposures obtained by the Reflection
Grating Spectrometer (RGS) cameras allows a thorough study of the complex
absorption and emission spectral features in the soft X-ray band.The three
combined exposures obtained in January 2001 and the two obtained in January and
July 2005 were analysed using the SPEX software. We detect a two-phase warm
absorber: a medium ionisation component (logxi~1.5-2.2 ergs s cm^{-1}) is
responsible for a deep absorption feature in the Unresolved Transition Array of
the Fe M-shell and for several absorption lines in the OVI-VIII band; a higher
ionisation phase with logxi~3 ergs s cm^{-1} is required to fit absorption in
the NeIX-X band. The ionisation state and the column density of the gas present
moderate variation from 2001 to 2005 for both phases. The high ionisation
component of the warm absorber has no effect in the Fe K band. No significant
velocity shift of the absorption lines is measured in the RGS data. Remarkably,
the 2005 spectra show emission features consistent with photoionisation in a
high density (n_e>10^{11} cm^{-3}) gas: a prominent OVII line triplet is
clearly observed in January 2005 and narrow Radiative Recombination Continua
(RRC) of OVII and CVI are observed in both 2005 data sets. A broad Gaussian
line around 21.7 Angstrom is also required to fit all the data sets. The
derived radial distance for the emission lines seems to suggest that the
photoionisation takes place within the optical Broad Line Region of the source.Comment: In press on A&A, replaced version includes language editing and typo
on velocities corrected in Table
The nature of the torus in the heavily obscured AGN Markarian 3: an X-ray study
In this paper we report the results of an X-ray monitoring campaign on the
heavily obscured Seyfert galaxy Markarian 3 carried out between the fall of
2014 and the spring of 2015 with NuSTAR, Suzaku and XMM-Newton. The hard X-ray
spectrum of Markarian 3 is variable on all the time scales probed by our
campaign, down to a few days. The observed continuum variability is due to an
intrinsically variable primary continuum seen in transmission through a large,
but still Compton-thin column density (N_H~0.8-1.110 cm).
If arranged in a spherical-toroidal geometry, the Compton scattering matter has
an opening angle ~66 degrees and is seen at a grazing angle through its upper
rim (inclination angle ~70 degrees). We report a possible occultation event
during the 2014 campaign. If the torus is constituted by a system of clouds
sharing the same column density, this event allows us to constrain their number
(175) and individual column density, [~(4.91.5)10
cm]. The comparison of IR and X-ray spectroscopic results with
state-of-the art "torus" models suggests that at least two thirds of the X-ray
obscuring gas volume might be located within the dust sublimation radius. We
report also the discovery of an ionized absorber, characterised by variable
resonant absorption lines due to He- and H-like iron. This discovery lends
support to the idea that moderate column density absorbers could be due to
clouds evaporated at the outer surface of the torus, possibly accelerated by
the radiation pressure due to the central AGN emission leaking through the
patchy absorber.Comment: Accepted for publication in MNRAS, 17 pages, 11 figures, 5 table
Extreme Warm Absorber variability in the Seyfert Galaxy Mrk 704
In about half of Seyfert galaxies, the X-ray emission is absorbed by an
optically thin, ionized medium, the so-called "Warm Absorber", whose origin and
location is still a matter of debate. The aims of this paper is to put more
constraints on the warm absorber by studying its variability. We analyzed the
X-ray spectra of a Seyfert 1 galaxy, Mrk 704, which was observed twice, three
years apart, by XMM-Newton. The spectra were well fitted with a two zones
absorber, possibly covering only partially the source. The parameters of the
absorbing matter - column density, ionization state, covering factor - changed
significantly between the two observations. Possible explanations for the more
ionized absorber are a torus wind (the source is a polar scattering one) or, in
the partial covering scenario, an accretion disk wind. The less ionized
absorber may be composed of orbiting clouds in the surroundings of the nucleus,
similarly to what already found in other sources, most notably NGC 1365.Comment: 10 pages. Accepted for publication in Astronomy & Astrophysic
The broad-band X-ray spectrum of the Seyfert 1 galaxy, MCG+8-11-11
We present a long (100 ks) Suzaku observation of one of the X-ray brightest
AGN, MCG+8-11-11. These data were complemented with the 54-month Swift BAT
spectrum, allowing us to perform a broad-band fit in the 0.6-150 keV range. The
fits performed in the 0.6-10 keV band give consistent results with respect to a
previous XMM-Newton observation, i.e. the lack of a soft excess, warm
absorption along the line of sight, a large Compton reflection component (R~1)
and the absence of a relativistic component of the neutral iron K
emission line. However, when the PIN and Swift BAT data are included, the
reflection amount drops significantly (R~0.2-0.3), and a relativistic iron line
is required, the latter confirmed by a phenomenological analysis in a
restricted energy band (3-10 keV). When a self-consistent model is applied to
the whole broadband data, the observed reflection component appears to be all
associated to the relativistic component of the iron K line. The
resulting scenario, though strongly model-dependent, requires that all the
reprocessing spectral components from Compton-thick material must be associated
to the accretion disc, and no evidence for the classical pc-scale torus is
found. The narrow core of the neutral iron K line is therefore produced
in a Compton-thin material, like the BLR, similarly to what found in another
Seyfert galaxy, NGC7213, but with the notable difference that MCG+8-11-11
presents spectral signatures from an accretion disc. The very low accretion
rate of NGC7213 could explain the lack of relativistic signatures in its
spectrum, but the absence of the torus in both sources is more difficult to
explain, since their luminosities are comparable, and their accretion rates are
completely different.Comment: 8 pages, 6 figure, accepted for publication in Astronomy and
Astrophysic
Probing the unified model in NGC 7314
We present a study of the complex absorbed X-ray spectrum of the Narrow Line
Seyfert 1 galaxy NGC 7314. We collected available public X-ray data from the
archives of XMM-Newton, Suzaku, and ASCA. The spectra were analyzed using the
fitting package SPEX. We find evidence of intrinsic neutral and ionized
absorption in the XMM-Newton EPIC-pn spectrum. The ionized gas presents three
significantly distinct ionization phases, although its kinematic properties
could not be disentangled. At least two of these phases are also detected in
the RGS spectrum, although with less significance due to the low statistics.
The ASCA and Suzaku spectra show larger neutral absorption but no ionized gas
signatures. The Fe Kalpha emission line is detected in all the observations
and, additionally, Fe XXVI in the EPIC-pn spectrum, and Fe Kbeta in the Suzaku
XIS spectrum. Using this observational evidence we construct a consistent
picture of the geometry of the system in the context of the unified model of
active galactic nuclei. The different observational properties are thus
interpreted as clouds of neutral gas moving across our line of sight, which
would be grazing a clumpy dusty torus.Comment: 9 pages, 8 figures. Accepted for publication in Astronomy and
Astrophysic
Transapical off-pump echo-guided mitral valve repair with neochordae implantation mid-term outcomes
Background: The NeoChord echo-guided transapical beating heart repair is a promising early-stage
minimally invasive surgical procedure for degenerative mitral valve (MV) regurgitation (DMR) correction.
The technique has been improved since its inception following procedure standardization, patient selection
optimization, and learning curve stabilization. We hereby present the mid-term clinical results through three
years of our large single center experience.
Methods: All consecutive patients with severe symptomatic DMR due to prolapse or flail of one or both
mitral leaflets that underwent the NeoChord procedure between November 2013 and June 2019 were
included. Patients were categorized according to MV anatomy; Type A isolated central posterior leaflet
prolapse and/or flail, Type B posterior multi-segment prolapse and/or flail, Type C anterior and/or bi-leaflet
prolapse or flail, Type D paracommissural prolapse and/or flail and/or significant leaflet and/or annular
calcifications. Patients underwent clinical and echocardiographic follow-up at one, three, six, twelve months
and yearly thereafter. Clinical outcomes and the composite primary endpoint (patient success) were defined
according to Mitral Valve Academic Research Consortium (MVARC) criteria. Mitral regurgitation (MR)
severity was graded as absent, mild, moderate and severe according to American Society of Echocardiography
(ASE) and European Society of Cardiology (ESC) guidelines.
Results: Two hundred and three patients were included; median follow-up was 24 months [interquartile
range (IQR), 9–36]. Median age was 64 years (IQR, 54–74 years), median Society of Thoracic Surgeons
(STS) Predicted Risk of Mortality (PROM) was 0.60% (IQR, 0.32–1.44%). There were 106 Type A patients
(52.2%), 68 Type B (33.5%), 16 Type C (7.9%), and 13 Type D (6.4%). Kaplan-Meier estimate of survival
was 99.0%±0.7% at one and two years and 94.0%±2.9% at three years. At one-year follow-up patient success
was 91.2%±2.0% and 111 patients (74%) presented a residual MR mild or less (1+). At three-year follow-up
patient success was 81.2%±3.8% and 32 patients (64%) had a residual MR mild or less (1+). Patient success
was significantly different according to anatomical type (P=0.001). Echocardiographic analysis showed a
significant acute left ventricle and left atrial reverse remodeling that was maintained up to three years.
Conclusions: The NeoChord echo-guided transapical beating heart repair procedure demonstrated good
clinical outcomes and echocardiographic results up to three-year follow-up
Early Science with the Large Millimeter Telescope: an energy-driven wind revealed by massive molecular and fast X-ray outflows in the Seyfert Galaxy IRAS 17020+4544
We report on the coexistence of powerful gas outflows observed in millimeter
and X-ray data of the Radio-Loud Narrow Line Seyfert 1 Galaxy IRAS 17020+4544.
Thanks to the large collecting power of the Large Millimeter Telescope, a
prominent line arising from the 12CO(1-0) transition was revealed in recent
observations of this source. The complex profile is composed by a narrow
double-peak line and a broad wing. While the double-peak structure may be
arising in a disk of molecular material, the broad wing is interpreted as the
signature of a massive outflow of molecular gas with an approximate bulk
velocity of -660 km/s. This molecular wind is likely associated to a
multi-component X-ray Ultra-Fast Outflow with velocities reaching up to ~0.1c
and column densities in the range 10^{21-23.9} cm^-2 that was reported in the
source prior to the LMT observations. The momentum load estimated in the two
gas phases indicates that within the observational uncertainties the outflow is
consistent with being propagating through the galaxy and sweeping up the gas
while conserving its energy. This scenario, which has been often postulated as
a viable mechanism of how AGN feedback takes place, has so far been observed
only in ULIRGs sources. IRAS 17020+4544 with bolometric and infrared luminosity
respectively of 5X10^{44} erg/s and 1.05X10^{11} L_sun appears to be an example
of AGN feedback in a NLSy1 Galaxy (a low power AGN). New proprietary
multi-wavelength data recently obtained on this source will allow us to
corroborate the proposed hypothesis.Comment: Accepted for publication on ApJ Letters, 9 pages, 4 figure
First high-resolution detection of a warm absorber in the Broad Line Radio Galaxy 3C 382
Recent high-resolution measurements suggest that the soft X-ray spectrum of
obscured Radio Galaxies (RG) exhibits signatures of photoionised gas (e.g. 3C
445 and 3C 33) similar to those observed in radio-quiet obscured Active
Galactic Nuclei (AGN). While signatures of warm absorbing gas covering a wide
range of temperature and ionisation states have been detected in about one half
of the population of nearby Seyfert 1 galaxies, no traces of warm absorber gas
have been reported to date in the high-resolution spectra of Broad Line Radio
Galaxies (BLRG). We present here the first detection of a soft X-ray warm
absorber in the powerful FRII BLRG 3C 382 using the Reflection Grating
Spectrometer (RGS) on-board XMM-Newton. The absorption gas appears to be highly
ionised, with column density of the order of 10^{22} cm^{-2}, ionisation
parameter log\xi>2 erg cm s^{-1} and outflow velocities of the order of 10^{3}
km s^{-1}. The absorption lines may come from regions located outside the
torus, however at distances less than 60 pc. This result may indicate that a
plasma ejected at velocities near the speed of light and a photoionised gas
with slower, outflow velocities can coexist in the same source beyond the Broad
Line Regions.Comment: 5 pages, 3 figures, 1 table, accepted for publication in MNRAS
Letter
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