513 research outputs found
Human rights in health systems frameworks: what is there, what is missing and why does it matter?
Global initiatives and recent G8 commitments to health systems strengthening have brought increased attention to factors affecting health system performance. While equity concerns and human rights language appear often in the global health discourse, their inclusion in health systems efforts beyond rhetorical pronouncements is limited. Building on recent work assessing the extent to which features compatible with the right to health are incorporated into national health systems, we examine how health systems frameworks have thus far integrated human rights concepts and human rights-based approaches to health in their conceptualisation. Findings point to the potential value of the inclusion of human rights in these articulations to increase the participation or involvement of clients in health systems, to broaden the concept of equity, to bring attention to laws and policies beyond regulation and to strengthen accountability mechanisms
The Soft-Excess in Mrk 509: Warm Corona or Relativistic Reflection?
We present the analysis of the first NuSTAR observations ( ks),
simultaneous with the last SUZAKU observations ( ks), of the active
galactic nucleus of the bright Seyfert 1 galaxy Mrk 509. The time-averaged
spectrum in the keV X-ray band is dominated by a power-law continuum
(), a strong soft excess around 1 keV, and signatures of
X-ray reflection in the form of Fe K emission ( keV), an Fe K
absorption edge ( keV), and a Compton hump due to electron scattering
( keV). We show that these data can be described by two very
different prescriptions for the soft excess: a warm ( keV) and
optically thick () Comptonizing corona, or a relativistically
blurred ionized reflection spectrum from the inner regions of the accretion
disk. While these two scenarios cannot be distinguished based on their fit
statistics, we argue that the parameters required by the warm corona model are
physically incompatible with the conditions of standard coronae. Detailed
photoionization calculations show that even in the most favorable conditions,
the warm corona should produce strong absorption in the observed spectrum. On
the other hand, while the relativistic reflection model provides a satisfactory
description of the data, it also requires extreme parameters, such as maximum
black hole spin, a very low and compact hot corona, and a very high density for
the inner accretion disk. Deeper observations of this source are thus necessary
to confirm the presence of relativistic reflection, and to further understand
the nature of its soft excess.Comment: Accepted for publication in ApJ, 18 pages, 7 figure
Evidence for Returning Disk Radiation in the Black Hole X-Ray Binary XTE J1550–564
We explore the accretion properties of the black hole X-ray binary XTE J1550−564 during its outbursts in 1998/99 and 2000. We model the disk, corona, and reflection components of X-ray spectra taken with the Rossi X-ray Timing Explorer, using the relxill suite of reflection models. The key result of our modeling is that the reflection spectrum in the very soft state is best explained by disk self-irradiation, i.e., photons from the inner disk are bent by the strong gravity of the black hole and reflected off the disk surface. This is the first known detection of thermal disk radiation reflecting off the inner disk. There is also an apparent absorption line at ~6.9 keV, which may be evidence of an ionized disk wind. The coronal electron temperature (kT_e) is, as expected, lower in the brighter outburst of 1998/99, explained qualitatively by more efficient coronal cooling due to irradiating disk photons. The disk inner radius is consistent with being within a few times the innermost stable circular orbit throughout the bright-hard-to-soft states (10 s of r_g in gravitational units). The disk inclination is low during the hard state, disagreeing with the binary inclination value, and very close to 90° in the soft state, recovering to a lower value when adopting a blackbody spectrum as the irradiating continuum
Reflection Spectroscopy of the Black Hole Binary XTE J1752-223 in its Long-Stable Hard State
We present a detailed spectral analysis of the Black Hole Binary XTE
J1752-223 in the hard state of its 2009 outburst. Regular monitoring of this
source by RXTE provided high signal-to-noise spectra along the outburst rise
and decay. During one full month this source stalled at 30\% of its peak
count rate at a constant hardness and intensity. By combining all the data in
this exceptionally-stable hard state, we obtained an aggregate PCA spectrum
(3-45 keV) with 100 million counts, and a corresponding HEXTE spectrum (20-140
keV) with 5.8 million counts. Implementing a version of our reflection code
with a physical model for Comptonization, we obtain tight constraints on
important physical parameters for this system. In particular, the inner
accretion disk is measured very close in, at .
Assuming , we find a relatively high black hole
spin (). Imposing a lamppost geometry, we obtain a low
inclination ( deg), which agrees with the upper limit found in the
radio ( deg). However, we note that this model cannot be statistically
distinguished from a non-lamppost model with free emissivity index, for which
the inclination is markedly higher. Additionally, we find a relatively cool
corona ( keV), and large iron abundance ( solar). We further
find that properly accounting for Comptonization of the reflection emission
improves the fit significantly and causes an otherwise low reflection fraction
() to increase by an order of magnitude, in line with geometrical
expectations for a lamppost corona. We compare these results with similar
investigations reported for GX 339-4 in its bright hard state.Comment: Accepted for publication in ApJ. 11 pages, 7 figure
The 2017 Failed Outburst of GX 339-4: Relativistic X-ray Reflection near the Black Hole Revealed by NuSTAR and Swift Spectroscopy
We report on the spectroscopic analysis of the black hole binary GX 339−4 during its recent 2017–2018 outburst, observed simultaneously by the Swift and NuSTAR observatories. Although during this particular outburst the source failed to make state transitions, and despite Sun constraints during the peak luminosity, we were able to trigger four different observations sampling the evolution of the source in the hard state. We show that even for the lowest-luminosity observations the NuSTAR spectra show clear signatures of X-ray reprocessing (reflection) in an accretion disk. Detailed analysis of the highest signal-to-noise spectra with our family of relativistic reflection models RELXILL indicates the presence of both broad and narrow reflection components. We find that a dual-lamppost model provides a superior fit when compared to the standard single lamppost plus distant neutral reflection. In the dual-lamppost model two sources at different heights are placed on the rotational axis of the black hole, suggesting that the narrow component of the Fe K emission is likely to originate in regions far away in the disk, but still significantly affected by its rotational motions. Regardless of the geometry assumed, we find that the inner edge of the accretion disk reaches a few gravitational radii in all our fits, consistent with previous determinations at similar luminosity levels. This confirms a very low degree of disk truncation for this source at luminosities above ~1% Eddington. Our estimates of R_(in) reinforce the suggested behavior for an inner disk that approaches the innermost regions as the luminosity increases in the hard state
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