461 research outputs found
The Nature of the Near-IR Core Source in 3C 433
We report the analysis of near-infrared imaging, polarimetric and
spectroscopic observations of the powerful radio galaxy 3C433, obtained with
the HST and UKIRT telescopes. The high spatial resolution of HST allows us to
study the near-nuclear regions of the galaxy (<1 kpc). In line with previous
observations, we find that 3C433 has an unresolved core source that is detected
in all near-IR bands, but dominates over the host galaxy emission at 2.05 um.
Our analysis reveals: (1) the presence of a dust lane aligned close to
perpendicular (PA=70\pm5\degr) to the inner radio jet axis
(PA=-12\pm2\degr); (2) a steep slope to the near-IR SED (;
F); (3) an apparent lack of broad permitted
emission lines at near-IR wavelengths, in particular the absence of a broad
Pa emission line; and (4) high intrinsic polarization for the
unresolved core nuclear source ( per cent), with an E-vector
perpendicular (PA=83.0\pm 2.3\degr) to the inner radio jet. Using five
independent techniques we determine an extinction to the compact core source in
the range 3<A_V<67 mag. An analysis of the long wavelength SED rules out a
synchrotron origin for the high near-IR polarization of the compact core
source. Therefore, scattering and dichroic extinction are plausible polarizing
mechanisms, although in both of these cases the broad permitted lines from the
AGN are required to have a width >10^4 km/s (FWHM) to escape detection in our
near-IR spectrum. Dichroic extinction is the most likely polarization mechanism
because it is consistent with the various available extinction estimates. In
this case, a highly ordered, coherent toroidal magnetic field must be present
in the obscuring structure close to the nucleus.Comment: 12 pages, 5 figures, accepted for publication in MNRA
Cystourethrography: The effect of reservoir height upon intravesical pressure
The effect of infusion height upon intravesical pressure during cystography was studied in three dogs and three patients. Results indicate that during bladder filling the intravesical pressure is independent of the reservoir height.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46721/1/247_2004_Article_BF00973671.pd
Chandra Observations of 3C Radio Sources with z<0.3: Nuclei, Diffuse Emission, Jets and Hotspots
We report on our Chandra Cycle 9 program to observe half of the 60
(unobserved by Chandra) 3C radio sources at z<0.3 for 8 ksec each. Here we give
the basic data: the X-ray intensity of the nuclei and any features associated
with radio structures such as hot spots and knots in jets. We have measured
fluxes in soft, medium and hard bands and are thus able to isolate sources with
significant intrinsic column density. For the stronger nuclei, we have applied
the standard spectral analysis which provides the best fit values of X-ray
spectral index and column density. We find evidence for intrinsic absorption
exceeding a column density of 10^{22} cm^{-2} for one third of our sources.Comment: 12 pages, 37 figures (the complete version of the paper with all
figures is available on line, see appendix for details), ApJ accepte
Supernovae 2016bdu and 2005gl, and their link with SN 2009ip-like transients: another piece of the puzzle
Supernova (SN) 2016bdu is an unusual transient resembling SN 2009ip. SN
2009ip-like events are characterized by a long-lasting phase of erratic
variability which ends with two luminous outbursts a few weeks apart. The
second outburst is significantly more luminous (about 3 mag) than the first. In
the case of SN 2016bdu, the first outburst (Event A) reached an absolute
magnitude M(r) ~ -15.3 mag, while the second one (Event B) occurred over one
month later and reached M(r) ~ -18 mag. By inspecting archival data, a faint
source at the position of SN 2016bdu is detectable several times in the past
few years. We interpret these detections as signatures of a phase of erratic
variability, similar to that experienced by SN 2009ip between 2008 and
mid-2012, and resembling the currently observed variability of the luminous
blue variable SN 2000ch in NGC 3432. Spectroscopic monitoring of SN 2016bdu
during the second peak initially shows features typical of a SN IIn. One month
after the Event B maximum, the spectra develop broad Balmer lines with P Cygni
profiles and broad metal features. At these late phases, the spectra resemble
those of a typical Type II SN. All members of this SN 2009ip-like group are
remarkably similar to the Type IIn SN 2005gl. For this object, the claim of a
terminal SN explosion is supported by the disappearance of the progenitor star.
The similarity with SN 2005gl suggests that all members of this family may
finally explode as genuine SNe, although the unequivocal detection of
nucleosynthesised elements in their nebular spectra is still missing.Comment: Submitted to MNRAS on April 10, 2017; re-submitted on June 23
including suggestions from the referee. 24 pages, 12 figures, 5 table
Lament as Transitional Justice
Works of human rights literature help to ground the formal rights system in an informal rights ethos. Writers have developed four major modes of human rights literature: protest, testimony, lament, and laughter. Through interpretations of poetry in Carolyn Forché’s anthology, Against Forgetting, and novels from Rwanda, the United States, and Bosnia, I focus on the mode of lament, the literature of mourning. Lament is a social and ritualized form, the purposes of which are congruent with the aims of transitional justice institutions. Both laments and truth commissions employ grieving narratives to help survivors of human rights trauma bequeath to the ghosts of the past the justice of a monument while renewing the survivors’ capacity for rebuilding civil society in the future. Human rights scholars need a broader, extra-juridical meaning for “transitional justice” if we hope to capture its power
A comparative HST imaging study of the host galaxies of radio-quiet quasars, radio-loud quasars and radio galaxies: Paper I
We present the first results from a major HST WFPC2 imaging study aimed at
providing the first statistically meaningful comparison of the morphologies,
luminosities, scalelengths and colours of the host galaxies of radio-quiet
quasars, radio-loud quasars, and radio galaxies. We describe the design of this
study and present the images which have been obtained for the first half of our
33-source sample. We find that the hosts of all three classes of luminous AGN
are massive elliptical galaxies, with scalelengths ~=10 kpc, and R-K colours
consistent with mature stellar populations. Most importantly this is the the
first unambiguous evidence that, just like radio-loud quasars, essentially all
radio-quiet quasars brighter than M_R = -24 reside in massive ellipticals. This
result removes the possibility that radio `loudness' is directly linked to host
galaxy morphology, but is however in excellent accord with the
black-hole/spheroid mass correlation recently highlighted by Magorrian et al.
(1998). We apply the relations given by Magorrian et al. to infer the expected
Eddington luminosity of the putative black hole at the centre of each of the
spheroidal host galaxies we have uncovered. Comparison with the actual nuclear
R-band luminosities suggests that the black holes in most of these galaxies are
radiating at a few percent of the Eddington luminosity; the brightest host
galaxies in our low-z sample are capable of hosting quasars with M_R = -28,
comparable to the most luminous quasars at z = 3. Finally we discuss our
host-derived black-hole masses in the context of the
radio-luminosity:black-hole mass correlation recently uncovered for nearby
galaxies by Franceschini et al. (1998), and the resulting implications for the
physical origin of radio loudness.Comment: Submitted for publication in the Astrophysical Journal, 55 pages of
latex, plus 12 postscript figures (Figures 1a-1s (greyscales of images and
model fits, and Figures 2a-2g (luminosity profiles and model fits) can be
downloaded from http://www.roe.ac.uk/astronomy/html/rjm1.shtml
Extended soft X-ray emission in 3CR radio galaxies at z < 0.3: High Excitation and Broad Line Galaxies
We analyze Chandra observations of diffuse soft X-ray emission associated
with a complete sample of 3CR radio galaxies at z < 0.3. In this paper we focus
on the properties of the spectroscopic sub-classes of high excitation galaxies
(HEGs) and broad line objects (BLOs). Among the 33 HEGs we detect extended (or
possibly extended) emission in about 40% of the sources; the fraction is even
higher (8/10) restricting the analysis to the objects with exposure times
larger than 10 ks. In the 18 BLOs, extended emission is seen only in 2 objects;
this lower detection rate can be ascribed to the presence of their bright X-ray
nuclei that easily outshine any genuine diffuse emission.
A very close correspondence between the soft X-ray and optical line
morphology emerges. We also find that the ratio between [O III] and extended
soft X-ray luminosity is confined within a factor of 2 around a median value of
5. Both results are similar to what is seen in Seyfert galaxies.
We discuss different processes that could explain the soft X-ray emission and
conclude that the photoionization of extended gas, coincident with the narrow
line region, is the favored mechanism.Comment: 15 pages, 11 figures. Accepted for publication on A&
Core components for effective infection prevention and control programmes: new WHO evidence-based recommendations
Abstract
Health care-associated infections (HAI) are a major public health problem with a significant impact on morbidity, mortality and quality of life. They represent also an important economic burden to health systems worldwide. However, a large proportion of HAI are preventable through effective infection prevention and control (IPC) measures. Improvements in IPC at the national and facility level are critical for the successful containment of antimicrobial resistance and the prevention of HAI, including outbreaks of highly transmissible diseases through high quality care within the context of universal health coverage. Given the limited availability of IPC evidence-based guidance and standards, the World Health Organization (WHO) decided to prioritize the development of global recommendations on the core components of effective IPC programmes both at the national and acute health care facility level, based on systematic literature reviews and expert consensus. The aim of the guideline development process was to identify the evidence and evaluate its quality, consider patient values and preferences, resource implications, and the feasibility and acceptability of the recommendations. As a result, 11 recommendations and three good practice statements are presented here, including a summary of the supporting evidence, and form the substance of a new WHO IPC guideline
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