463 research outputs found
Disc-Jet coupling in the LMXB 4U1636-53 from INTEGRAL
We report on the spectral analysis results of the neutron star, atoll type,
low mass X-ray Binary 4U1636-53 observed by INTEGRAL and BeppoSAX satellites.
Spectral behavior in three different epochs corresponding to three different
spectral states has been deeply investigated. Two data set spectra show a
continuum well described by one or two soft blackbody plus a Comptonized
components with changes in the Comptonizing electrons and black body
temperature and the accretion rates, which are typical of the spectral
transitions from high to low state. In one occasion INTEGRAL spectrum shows,
for first time in this source, a hard tail dominating the emission above 30
keV. The total spectrum is fitted as the sum of a Comptonized component similar
to soft state and a power-law component (Gamma=2.76), indicating the presence
of a non thermal electron distribution of velocities. In this case, a
comparison with hard tails detected in soft states from neutron stars systems
and some black hole binaries suggests that a similar mechanism could originate
these components in both cases.Comment: 6 pages, 4 figures, 2 tables. accepted Ap
Swift-XRT observation of 34 new INTEGRAL/IBIS AGNs: discovery of Compton thick and other peculiar sources
For a significant number of the sources detected at high energies (>10 keV)
by the INTEGRAL/IBIS and Swift/BAT instruments there is either a lack
information about them in the 2-10 keV range or they are totally unidentified.
Herein, we report on a sample of 34 IBIS AGN or AGN candidate objects for which
there is X-ray data in the Swift/XRT archive. Thanks to these X-ray follow up
observations, the identification of the gamma ray emitters has been possible
and the spectral shape in terms of photon index and absorption has been
evaluated for the first time for the majority of our sample sources. The
sample, enlarged to include 4 more AGN already discussed in the literature, has
been used to provide photon index and column density distribution. We obtain a
mean value of 1.88 with a dispersion of 0.12, i.e. typical of an AGN sample.
Sixteen objects (47%) have column densities in excess of 10^{22} cm^{-2} and,
as expected, a large fraction of the absorbed sources are within the Sey 2
sample. We have provided a new diagnostic tool (NH versus
F(2-10)keV/F(20-100)keV softness ratio) to isolate peculiar objects; we find at
least one absorbed Sey 1 galaxy, 3 Compton thick AGN candidates; and one secure
example of a "true" type 2 AGN. Within the sample of 10 still unidentified
objects, 3 are almost certainly AGN of type 2; 3 to 4 have spectral slopes
typical of AGN; and two are located high on the galactic plane and are strong
enough radio emitters so that can be considered good AGN candidates.Comment: 15 pages, 5 figures, ApJ accepte
Precautionary labelling of foods for allergen content: are we ready for a global framework?
© 2014 Allen et al.; licensee BioMed Central Ltd.Food allergy appears to be on the rise with the current mainstay of treatment centred on allergen avoidance. Mandatory allergen labelling has improved the safety of food for allergic consumers. However an additional form of voluntary labelling (termed precautionary allergen labelling) has evolved on a wide range of packaged goods, in a bid by manufacturers to minimise risk to customers, and the negative impact on business that might result from exposure to trace amounts of food allergen present during cross-contamination during production. This has resulted in near ubiquitous utilisation of a multitude of different precautionary allergen labels with subsequent confusion amongst many consumers as to their significance. The global nature of food production and manufacturing makes harmonisation of allergen labelling regulations across the world a matter of increasing importance. Addressing inconsistencies across countries with regards to labelling legislation, as well as improvement or even banning of precautionary allergy labelling are both likely to be significant steps forward in improved food safety for allergic families. This article outlines the current status of allergen labelling legislation around the world and reviews the value of current existing precautionary allergen labelling for the allergic consumer. We strongly urge for an international framework to be considered to help roadmap a solution to the weaknesses of the current systems, and discuss the role of legislation in facilitating this
IGR J22517+2218=MG3 J225155+2217: a new gamma-ray lighthouse in the distant Universe
We report on the identification of a new soft gamma ray source, namely IGR
J22517+2218, detected with IBIS/INTEGRAL. The source, which has an observed
20-100 keV flux of ~4 x10^-11 erg cm-2 s-1, is spatially coincident with MG3
J225155+2217, a quasar at z=3.668. The Swift/XRT 0.5-10 keV continuum is flat
(Gamma=1.5) with evidence for a spectral curvature below 1-2 keV either due to
intrinsic absorption (NH=3 +/- 2 x 10^22 cm-2) or to a change in slope (Delta
Gamma= 0.5). X-ray observations indicate flux variability over a 6 days period
which is further supported by a flux mismatch between Swift and INTEGRAL
spectra. IGR J22517+2218 is radio loud and has a flat radio spectrum; optically
it is a broad line emitting quasar with the atypical property of hosting a
narrow line absorption system. The Source Spectral Energy Distribution is
unusual compared to blazars of similar type: either it has the synchrotron peak
in the X/gamma-ray band (i.e. much higher than generally observed) or the
Compton peak in the MeV range (i.e. lower than typically measured). IGR
J22517+2218=MG3 J225155+2217 is the second most distant blazar detected above
20 keV and a gamma-ray lighthouse shining from the edge of our Universe.Comment: 4 pages, 4 figures, Accepted for publication in Astrophysical Journal
Letter
BL Lacertae identifications in a ROSAT-selected sample of Fermi unidentified objects
The optical spectroscopic followup of 27 sources belonging to a sample of 30
high-energy objects selected by positionally cross correlating the first
Fermi/LAT Catalog and the ROSAT All-Sky Survey Bright Source Catalog is
presented here. It has been found or confirmed that 25 of them are BL Lacertae
objects (BL Lacs), while the remaining two are Galactic cataclysmic variables
(CVs). This strongly suggests that the sources in the first group are
responsible for the GeV emission detected with Fermi, while the two CVs most
likely represent spurious associations. We thus find an 80% a posteriori
probability that the sources selected by matching GeV and X-ray catalogs belong
to the BL Lac class. We also show suggestions that the BL Lacs selected with
this approach are probably high-synchrotron-peaked sources and in turn good
candidates for the detection of ultra-high-energy (TeV) photons from them.Comment: 16 pages, 9 figures, 4 tables, one appendix, accepted for publication
on A&A, main journal. Tables 1-3 and Figures 2-6 will only be published in
the electronic edition of the journa
The 3rd IBIS/ISGRI soft gamma-ray survey catalog
In this paper we report on the third soft gamma-ray source catalog obtained
with the IBIS/ISGRI gamma-ray imager on board the INTEGRAL satellite. The
scientific dataset is based on more than 40 Ms of high quality observations
performed during the first three and a half years of Core Program and public
IBIS/ISGRI observations. Compared to previous IBIS/ISGRI surveys, this catalog
includes a substantially increased coverage of extragalactic fields, and
comprises more than 400 high-energy sources detected in the energy range 17-100
keV, including both transients and faint persistent objects which can only be
revealed with longer exposure times.Comment: Accepted for publication in ApJ Suppl.; 11 pages; 4 figures Minor
changes to conten
PIPE-cloned human IgE, IgG1 and IgG4 antibodies: New tools for investigating cowâs milk allergy and tolerance
Cow's milk (CM) allergy (CMA) is defined as an immune-mediated adverse response to CM proteins. 2% to 3% of children are suffering from CMA, but many develop natural tolerance after 3-4 years.1,S01 Food allergen immunotherapy (FA-AIT) applying increasing antigen doses (oral immunotherapy, OIT) can contribute to improvement of CMA,S02 with variable clinical efficacy,2,S03 but immunologically often resulting in decreased specific IgE levels and increased specific IgG4 levelsS04,S05. IgG4 is (a) anti-inflammatory as it does not activate the complement system; (b) bi-specific due to fab-arm exchange and, thus, has less crosslinking capacity than IgE, but has (c) blocking capacity.3 The interplay of IgE and IgG4 may hence be decisive for the immune balance in CMA.This work was supported by the Austrian Science Fund (FWF) grants MCCA W1248-B30 and SFB F4606-B28 to EJJ. CP received an EFIS-IL short-term research fellowship for a research visit at Biocruces Bizkaia Health Research Institute, Barakaldo, Spain. The research was funded by the National Institute for Health Research (NIHR) Biomedical Research Centre (BRC) based at Guy's and St Thomas' NHS Foundation Trust and King's College London (IS-BRC-1215-20006) (SNK). The authors acknowledge support by the Medical Research Council (MR/L023091/1) (SNK); Breast Cancer Now (147), working in partnership with Walk the Walk (SNK); Cancer Research UK (C30122/A11527; C30122/A15774) (SNK); Cancer Research UK Kingâs Health Partners Centre at Kingâs College London (SNK); CRUK/NIHR in England/DoH for Scotland, Wales and Northern Ireland Experimental Cancer Medicine Centre (C10355/A15587) (SNK). The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health. Additionally, was this work funded by Instituto de Salud Carlos III through the project "PI16/01223" (Co-funded by European Regional Development Fund; âA way to make Europeâ) to FB and by the Department of Health, Basque Government through the project â2019111031â to OZ. OZ is recipient of a Sara Borrell 2017 postdoctoral contract âCD17/00128â funded by Instituto de Salud Carlos III (Co-funded by European Social Fund; âInvesting in your future")
The first detection of Compton Reflection in the Low-Mass X-ray Binary 4U1705-44 with INTEGRAL and BeppoSAX
We present data from INTEGRAL and BeppoSAX satellites showing spectral state
transitions of the neutron-star, atoll-type, low-mass X-ray binary 1705-44. Its
energy spectrum can be described as the sum of one or two blackbody components,
a 6.4-keV Fe line, and a component due to thermal Comptonization. In addition,
and for the first time in this source, we find a strong signature of Compton
reflection, presumably due to illumination of the optically-thick accretion
disk by the Comptonization spectrum. The two blackbody components, which the
soft-state data require, presumably arise from both the disk and the
neutron-star surface. The Comptonization probably takes place in a hot inner
flow irradiated by some of the blackbody photons. The spectral transitions are
shown to be associated with variations in the bolometric luminosity, most
likely proportional to the accretion rate. Indipendentely from the spectral
state, we also see changes in the temperature of the Comptonizing electrons and
the strength of Compton reflection.Comment: accepted Ap
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