176 research outputs found
Discovery of the lensed quasar eRASS1 J050129.5-073309 with eROSITA and
We report the discovery and spectroscopic identification of the bright doubly
lensed quasar eRASS1 J050129.5-073309 at redshift , selected from the
first all-sky survey of the eROSITA
telescope and the EDR3 catalog. We systematically search for
extragalactic sources with eROSITA X-ray positions having multiple
counterparts and have started spectroscopic follow-up of the most promising
candidates using long-slit spectroscopy with NTT/EFOSC2 to confirm the lens
nature. The two images are separated by and their average
-band magnitudes are 16.95 and 17.33. Legacy Survey DR10 imaging and
image modeling reveal both the lensing galaxy and tentatively the lensed image
of the quasar host galaxy. Archival optical light curves show evidence of a
variability time delay with the fainter component lagging the brighter by about
100 days. The fainter image has also decreased its brightness by about 1
magnitude since 2019. This dimming was still obvious at the time of the
spectroscopic observations and is probably caused by microlensing. The optical
spectroscopic follow-up obtained from NTT/EFOSC2 and the evidence provided by
the imaging and timing analysis allow us to confirm the lensed nature of eRASS1
J050129.5-073309.Comment: Accepted for publication in A&
The Subaru Coronagraphic Extreme Adaptive Optics system: enabling high-contrast imaging on solar-system scales
The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument is a
multipurpose high-contrast imaging platform designed for the discovery and
detailed characterization of exoplanetary systems and serves as a testbed for
high-contrast imaging technologies for ELTs. It is a multi-band instrument
which makes use of light from 600 to 2500nm allowing for coronagraphic direct
exoplanet imaging of the inner 3 lambda/D from the stellar host. Wavefront
sensing and control are key to the operation of SCExAO. A partial correction of
low-order modes is provided by Subaru's facility adaptive optics system with
the final correction, including high-order modes, implemented downstream by a
combination of a visible pyramid wavefront sensor and a 2000-element deformable
mirror. The well corrected NIR (y-K bands) wavefronts can then be injected into
any of the available coronagraphs, including but not limited to the phase
induced amplitude apodization and the vector vortex coronagraphs, both of which
offer an inner working angle as low as 1 lambda/D. Non-common path, low-order
aberrations are sensed with a coronagraphic low-order wavefront sensor in the
infrared (IR). Low noise, high frame rate, NIR detectors allow for active
speckle nulling and coherent differential imaging, while the HAWAII 2RG
detector in the HiCIAO imager and/or the CHARIS integral field spectrograph
(from mid 2016) can take deeper exposures and/or perform angular, spectral and
polarimetric differential imaging. Science in the visible is provided by two
interferometric modules: VAMPIRES and FIRST, which enable sub-diffraction
limited imaging in the visible region with polarimetric and spectroscopic
capabilities respectively. We describe the instrument in detail and present
preliminary results both on-sky and in the laboratory.Comment: Accepted for publication, 20 pages, 10 figure
Low-lying quadrupole collective states of the light and medium Xenon isotopes
Collective low lying levels of light and medium Xenon isotopes are deduced
from the Generalized Bohr Hamiltonian (GBH). The microscopic seven functions
entering into the GBH are built from a deformed mean field of the Woods-Saxon
type. Theoretical spectra are found to be close to the ones of the experimental
data taking into account that the calculations are completely microscopic, that
is to say, without any fitting of parameters.Comment: 8 pages, 4 figures, 1 tabl
Central radio galaxies in galaxy clusters: Joint surveys by eROSITA and ASKAP
The extended ROentgen Survey with an Imaging Telescope Array (eROSITA)
telescope onboard the Spectrum-Roentgen-Gamma (SRG) mission has finished the
first eROSITA All-Sky Survey (eRASS:1), and detected 10 galaxy clusters in
the western Galactic hemisphere. In the radio band, the Australian Square
Kilometre Array Pathfinder (ASKAP) telescope finished its pilot 1 phase of the
project 'Evolutionary Map of the Universe' (EMU) with 220.000 sources in a 270
deg field overlapping with eRASS:1. These two surveys are used to study
radio-mode Active Galactic Nuclei (AGN) in clusters. In order to understand the
efficiency of radio-mode feedback at the centers of galaxy clusters, we relate
the radio properties of brightest cluster galaxies (BCG) to the X-ray
properties of the host clusters. We identify the central radio sources in
eRASS:1 clusters or calculate corresponding upper limits on the radio
luminosity. Then, we derive relations between the X-ray properties of the
clusters and the radio properties of the corresponding central radio source. We
also apply a mid-infrared color criterion using WISE colors to identify AGN. In
total we investigate a sample of 75 clusters. We find a statistically
significant correlation between the X-ray luminosity of the cluster and the 944
MHz radio luminosity of the corresponding central radio galaxy. There is also a
positive trend between the radio power and the largest linear size (LLS) of the
radio source. The density and the LLS do not show any correlation. We find that
in high luminosity clusters with L_X > erg s the kinetic
luminosity of the radio jets is not longer correlated with the X-ray luminosity
and discuss various reasons. We find an anti-correlation between the central
cooling time t_cool and the radio luminosity L_R indicating a need for more
powerful AGN in clusters with short central cooling times.Comment: 16 pages, 12 figures, accepted for publication in A&
Effects of acute glucocorticoid blockade on metabolic dysfunction in patients with type 2 diabetes with and without fatty liver
To investigate the potential of therapies which reduce glucocorticoid action in patients with Type 2 diabetes we performed a randomized, double-blinded, placebo-controlled crossover study of acute glucocorticoid blockade, using the glucocorticoid receptor antagonist RU38486 (mifepristone) and cortisol biosynthesis inhibitor (metyrapone), in 14 men with Type 2 diabetes. Stable isotope dilution methodologies were used to measure the rates of appearance of glucose, glycerol, and free fatty acids (FFAs), including during a low-dose (10 mU·m −2·min−1) hyperinsulinemic clamp, and subgroup analysis was conducted in patients with high or low liver fat content measured by magnetic resonance spectroscopy (n = 7/group). Glucocorticoid blockade lowered fasting glucose and insulin levels and improved insulin sensitivity of FFA and glycerol turnover and hepatic glucose production. Among this population with Type 2 diabetes high liver fat was associated with hyperinsulinemia, higher fasting glucose levels, peripheral and hepatic insulin resistance, and impaired suppression of FFA oxidation and FFA and glycerol turnover during hyperinsulinemia. Glucocorticoid blockade had similar effects in those with and without high liver fat. Longer term treatments targeting glucocorticoid action may be useful in Type 2 diabetes with and without fatty liver
Glutamine supplementation
Intravenous glutamine supplementation is standard care when parenteral nutrition is given for critical illness. There are data of a reduced mortality when glutamine supplementation is given. In addition, standard commercial products for parenteral nutrition do not contain any glutamine due to glutamine instability in aqueous solutions. For the majority of critical ill patients who are fed enterally, the available evidence is insufficient to recommend glutamine supplementation. Standard formulation of enteral nutrition contains some glutamine: 2-4 g/L. However, this dose is insufficient to normalize glutamine plasma concentration
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