9 research outputs found
Time Evolving Photo Ionisation Device (TEPID): a novel code for out-of-equilibrium gas ionisation
Photoionisation is one of the main mechanisms at work in the gaseous
environment of bright astrophysical sources. Many information on the gas
physics, chemistry and kinematics, as well as on the ionising source itself,
can be gathered through optical to X-ray spectroscopy. While several public
time equilibrium photoionisation codes are readily available and can be used to
infer average gas properties at equilibrium, time-evolving photoionisation
models have only very recently started to become available. They are needed
when the ionising source varies faster than the typical gas equilibration
timescale. Indeed, using equilibrium models to analyse spectra of
non-equilibrium gas may lead to inaccurate results and prevents a solid
assessment of the gas density, physics and geometry. We present our novel
Time-Evolving PhotoIonisation Device (TEPID), which self-consistently solves
time evolving photoionisation equations (thermal and ionisation balance) and
follows the response of the gas to changes of the ionising source. The code can
be applied to a variety of astrophysical scenarios and produces time-resolved
gas absorption spectra to fit the data. To describe the main features of TEPID,
we apply it to two dramatically different astrophysical scenarios: a typical
ionised absorber observed in the X-ray spectra of Active Galactic Nuclei (e.g.
Warm Absorbers and UFOs) and the circumburst environment of a Gamma-Ray Burst.
In both cases, the gas energy and ionisation balances vary as a function of
time, gas density and distance from the ionising source. Time evolving
ionisation leads to unique ionisation patterns which cannot be reproduced by
stationary codes when the gas is out of equilibrium. This demonstrates the need
for codes such as TEPID in view of the up-coming high-resolution X-ray
spectrometers onboard missions like XRISM or Athena.Comment: Accepted for publication on Astronomy & Astrophysics. 23 pages, 25
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The lively accretion disc in NGC 2992. III. Tentative evidence of rapid Ultra Fast Outflow variability
We report on the 2019 XMM-Newton+NuSTAR monitoring campaign of the Seyfert
galaxy NGC 2992, observed at one of its highest flux levels in the X-rays. The
time-averaged spectra of the two XMM-Newton orbits show Ultra Fast Outflows
(UFOs) absorbing structures above 9 keV with significance. A
detailed investigation of the temporal evolution on a 5 ks time scale
reveals UFO absorption lines at a confidence level 95% (2) in 8 out
of 50 XMM-Newton segments, estimated via Monte Carlo simulations. We observe a
wind variability corresponding to a length scale of 5 Schwarzschild radii
. Adopting the novel Wind in the Ionised Nuclear Environment (WINE) model,
we estimate the outflowing gas velocity (), column density
() and ionisation state ($\log(\xi_0/erg\ cm\
s^{-1})=3.7-4.7\dot{M}_{out}\simeq0.3-0.8 M_{\odot} yr^{-1}\dot{p}_{out}\simeq 20-90 L_{Bol}/c\dot{E}_K \simeq 2-25 L_{Bol}\approx\approx\approx 5 r_S, 10^{11} {cm}^{-3}$, respectively.Comment: Accepted for publication in the Astrophysical Journal. 21 pages, 11
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The WISSH quasars project XI. The mean Spectral Energy Distribution and Bolometric Corrections of the most luminous quasars
Hyper-luminous Quasi-Stellar Objects (QSOs) represent the ideal laboratory to
investigate Active Galactic Nuclei (AGN) feedback mechanism since their
formidable energy release causes powerful winds at all scales and thus the
maximum feedback is expected.
We aim at deriving the mean Spectral Energy Distribution (SED) of a sample of
85 WISE-SDSS Selected Hyper-luminous (WISSH) quasars. Since the SED provides a
direct way to investigate the AGN structure, our goal is to understand if
quasars at the bright end of the luminosity function have peculiar properties
compared to the bulk of the population. We built a mean intrinsic SED after
correcting for the dust extinction, absorption and emission lines and
intergalactic medium absorption. We also derived bolometric, IR band and
monochromatic luminosities together with bolometric corrections at lambda =
5100 A and 3 micron. We define a new relation for the 3 micron bolometric
correction. We find that the mean SED of hyper-luminous WISSH QSOs is different
from that of less luminous sources, i.e. a relatively lower X-ray emission and
a near and mid IR excess which can be explained assuming a larger dust
contribution. WISSH QSOs have stronger emission from both warm and very hot
dust, the latter being responsible for shifting the typical dip of the AGN SED
from 1.3 to 1.1 micron. We also derived the mean SEDs of two sub-samples
created according to the presence of Broad Absorption Lines and equivalent
width of CIV line. We confirm that BALs are X-ray weak and that they have a
reddened UV-optical continuum. We also find that BALs tend to have stronger
emission from the hot dust component. This analysis suggests that
hyper-luminous QSOs have a peculiar SED compared to less luminous objects. It
is therefore critical to use SED templates constructed exclusively from very
bright quasars samples when dealing with particularly luminous sources.Comment: Accepted for publication in A&A. 20 pages, 15 figure
The Athena X-ray Integral Field Unit: a consolidated design for the system requirement review of the preliminary definition phase
The Athena X-ray Integral Unit (X-IFU) is the high resolution X-ray
spectrometer, studied since 2015 for flying in the mid-30s on the Athena space
X-ray Observatory, a versatile observatory designed to address the Hot and
Energetic Universe science theme, selected in November 2013 by the Survey
Science Committee. Based on a large format array of Transition Edge Sensors
(TES), it aims to provide spatially resolved X-ray spectroscopy, with a
spectral resolution of 2.5 eV (up to 7 keV) over an hexagonal field of view of
5 arc minutes (equivalent diameter). The X-IFU entered its System Requirement
Review (SRR) in June 2022, at about the same time when ESA called for an
overall X-IFU redesign (including the X-IFU cryostat and the cooling chain),
due to an unanticipated cost overrun of Athena. In this paper, after
illustrating the breakthrough capabilities of the X-IFU, we describe the
instrument as presented at its SRR, browsing through all the subsystems and
associated requirements. We then show the instrument budgets, with a particular
emphasis on the anticipated budgets of some of its key performance parameters.
Finally we briefly discuss on the ongoing key technology demonstration
activities, the calibration and the activities foreseen in the X-IFU Instrument
Science Center, and touch on communication and outreach activities, the
consortium organisation, and finally on the life cycle assessment of X-IFU
aiming at minimising the environmental footprint, associated with the
development of the instrument. Thanks to the studies conducted so far on X-IFU,
it is expected that along the design-to-cost exercise requested by ESA, the
X-IFU will maintain flagship capabilities in spatially resolved high resolution
X-ray spectroscopy, enabling most of the original X-IFU related scientific
objectives of the Athena mission to be retained. (abridged).Comment: 48 pages, 29 figures, Accepted for publication in Experimental
Astronomy with minor editin
The Athena X-ray Integral Field Unit: a consolidated design for the system requirement review of the preliminary definition phase
The Athena X-ray Integral Unit (X-IFU) is the high resolution X-ray spectrometer studied since 2015 for flying in the mid-30s on the Athena space X-ray Observatory. Athena is a versatile observatory designed to address the Hot and Energetic Universe science theme, as selected in November 2013 by the Survey Science Committee. Based on a large format array of Transition Edge Sensors (TES), X-IFU aims to provide spatially resolved X-ray spectroscopy, with a spectral resolution of 2.5 eV (up to 7 keV) over a hexagonal field of view of 5 arc minutes (equivalent diameter). The X-IFU entered its System Requirement Review (SRR) in June 2022, at about the same time when ESA called for an overall X-IFU redesign (including the X-IFU cryostat and the cooling chain), due to an unanticipated cost overrun of Athena. In this paper, after illustrating the breakthrough capabilities of the X-IFU, we describe the instrument as presented at its SRR (i.e. in the course of its preliminary definition phase, so-called B1), browsing through all the subsystems and associated requirements. We then show the instrument budgets, with a particular emphasis on the anticipated budgets of some of its key performance parameters, such as the instrument efficiency, spectral resolution, energy scale knowledge, count rate capability, non X-ray background and target of opportunity efficiency. Finally, we briefly discuss the ongoing key technology demonstration activities, the calibration and the activities foreseen in the X-IFU Instrument Science Center, touch on communication and outreach activities, the consortium organisation and the life cycle assessment of X-IFU aiming at minimising the environmental footprint, associated with the development of the instrument. Thanks to the studies conducted so far on X-IFU, it is expected that along the design-to-cost exercise requested by ESA, the X-IFU will maintain flagship capabilities in spatially resolved high resolution X-ray spectroscopy, enabling most of the original X-IFU related scientific objectives of the Athena mission to be retained. The X-IFU will be provided by an international consortium led by France, The Netherlands and Italy, with ESA member state contributions from Belgium, Czech Republic, Finland, Germany, Poland, Spain, Switzerland, with additional contributions from the United States and Japan.The French contribution to X-IFU is funded by CNES, CNRS and CEA. This work has been also supported by ASI (Italian Space Agency) through the Contract 2019-27-HH.0, and by the ESA (European Space Agency) Core Technology Program (CTP) Contract No. 4000114932/15/NL/BW and the AREMBES - ESA CTP No.4000116655/16/NL/BW. This publication is part of grant RTI2018-096686-B-C21 funded by MCIN/AEI/10.13039/501100011033 and by âERDF A way of making Europeâ. This publication is part of grant RTI2018-096686-B-C21 and PID2020-115325GB-C31 funded by MCIN/AEI/10.13039/501100011033
Perception of hepatitis B virus infection reactivation-related issues among specialists managing hematologic malignancies: result of an Italian survey
Hepatitis B virus (HBV) reactivation strongly affects the practice of physicians dealing with hematological malignancies. In this respect, in collaboration with the Italian Lymphoma Foundation we developed a descriptive study of the real-life approach of physicians caring for patients with these diseases. A questionnaire was designed to explore the perception of HBV reactivation-related issues. Fifty-nine Italian Lymphoma Foundation-affiliated institutions participated, and 504 questionnaires were sent out. Forty institutions (67.8%) returned 154 (30.5%) completed questionnaires. The largest majority (91.5%, 141/154) were aware of possible HBV reactivation as a consequence of immunosuppression. Most of the participants providing an answer (93.3%; 126/135) performed universal screening, and were aware of strategies for managing reactivation (96.4%, 132/137). Specialists treating lymphoma show a high level of awareness concerning the management of HBV reactivation under immunosuppression. However, uncertainties regarding the issue of HBV reactivation still emerge in this setting, and thus continuing collaborative effort between hepatologists and hematologists is necessary
The Athena X-ray Integral Field Unit: a consolidated design for the system requirement review of the preliminary definition phase
48 pages, 29 figures, submitted for publication in Experimental AstronomyThe Athena X-ray Integral Unit (X-IFU) is the high resolution X-ray spectrometer, studied since 2015 for flying in the mid-30s on the Athena space X-ray Observatory, a versatile observatory designed to address the Hot and Energetic Universe science theme, selected in November 2013 by the Survey Science Committee. Based on a large format array of Transition Edge Sensors (TES), it aims to provide spatially resolved X-ray spectroscopy, with a spectral resolution of 2.5 eV (up to 7 keV) over an hexagonal field of view of 5 arc minutes (equivalent diameter). The X-IFU entered its System Requirement Review (SRR) in June 2022, at about the same time when ESA called for an overall X-IFU redesign (including the X-IFU cryostat and the cooling chain), due to an unanticipated cost overrun of Athena. In this paper, after illustrating the breakthrough capabilities of the X-IFU, we describe the instrument as presented at its SRR, browsing through all the subsystems and associated requirements. We then show the instrument budgets, with a particular emphasis on the anticipated budgets of some of its key performance parameters. Finally we briefly discuss on the ongoing key technology demonstration activities, the calibration and the activities foreseen in the X-IFU Instrument Science Center, and touch on communication and outreach activities, the consortium organisation, and finally on the life cycle assessment of X-IFU aiming at minimising the environmental footprint, associated with the development of the instrument. It is expected that thanks to the studies conducted so far on X-IFU, along the design-to-cost exercise requested by ESA, the X-IFU will maintain flagship capabilities in spatially resolved high resolution X-ray spectroscopy, enabling most of the original X-IFU related scientific objectives of the Athena mission to be retained (abridged)
The Athena X-ray Integral Field Unit: a consolidated design for the system requirement review of the preliminary definition phase
48 pages, 29 figures, submitted for publication in Experimental AstronomyThe Athena X-ray Integral Unit (X-IFU) is the high resolution X-ray spectrometer, studied since 2015 for flying in the mid-30s on the Athena space X-ray Observatory, a versatile observatory designed to address the Hot and Energetic Universe science theme, selected in November 2013 by the Survey Science Committee. Based on a large format array of Transition Edge Sensors (TES), it aims to provide spatially resolved X-ray spectroscopy, with a spectral resolution of 2.5 eV (up to 7 keV) over an hexagonal field of view of 5 arc minutes (equivalent diameter). The X-IFU entered its System Requirement Review (SRR) in June 2022, at about the same time when ESA called for an overall X-IFU redesign (including the X-IFU cryostat and the cooling chain), due to an unanticipated cost overrun of Athena. In this paper, after illustrating the breakthrough capabilities of the X-IFU, we describe the instrument as presented at its SRR, browsing through all the subsystems and associated requirements. We then show the instrument budgets, with a particular emphasis on the anticipated budgets of some of its key performance parameters. Finally we briefly discuss on the ongoing key technology demonstration activities, the calibration and the activities foreseen in the X-IFU Instrument Science Center, and touch on communication and outreach activities, the consortium organisation, and finally on the life cycle assessment of X-IFU aiming at minimising the environmental footprint, associated with the development of the instrument. It is expected that thanks to the studies conducted so far on X-IFU, along the design-to-cost exercise requested by ESA, the X-IFU will maintain flagship capabilities in spatially resolved high resolution X-ray spectroscopy, enabling most of the original X-IFU related scientific objectives of the Athena mission to be retained (abridged)