Aims. We study the circumstellar evolution of the binary HD 101584, consisting of a post-AGB star and a low-mass companion, which is most likely a post-common-envelope-evolution system. Methods. We ...used ALMA observations of the 12CO, 13CO, and C18O J = 2−1 lines and the 1.3 mm continuum to determine the morphology, kinematics, masses, and energetics of the circumstellar environment. Results. The circumstellar medium has a bipolar hour-glass structure, seen almost pole-on, formed by an energetic jet, ≈150 km s-1. We conjecture that the circumstellar morphology is related to an event that took place ≈500 yr ago, possibly a capture event where the companion spiraled in towards the AGB star. However, the kinetic energy of the accelerated gas exceeds the released orbital energy, and, taking into account the expected energy transfer efficiency of the process, the observed phenomenon does not match current common-envelope scenarios. This suggests that another process must augment, or even dominate, the ejection process. A significant amount of material resides in an unresolved region, presumably in the equatorial plane of the binary system.
This paper presents a survey of microwave front-end receivers installed at radio telescopes throughout the world. This unprecedented analysis was conducted as part of a review of front-end ...developments for Italian radio telescopes, initiated by the Italian National Institute for Astrophysics in 2016. Fifteen international radio telescopes have been selected to be representative of the instrumentation used for radio astronomical observations in the frequency domain from 300 MHz to 116 GHz. A comprehensive description of the existing receivers is presented and their characteristics are compared and discussed. The observing performances of the complete receiving chains are also presented. An overview of ongoing developments illustrates and anticipates future trends in front-end projects to meet the most ambitious scientific research goals.
Context. During the asymptotic giant branch (AGB) phase, stars undergo thermal pulses − short-lived phases of explosive helium burning in a shell around the stellar core. Thermal pulses lead to the ...formation and mixing-up of new elements to the stellar surface. They are hence fundamental to the chemical evolution of the star and its circumstellar envelope. A further consequence of thermal pulses is the formation of detached shells of gas and dust around the star, several of which have been observed around carbon-rich AGB stars. Aims. We aim to determine the physical properties of the detached gas shell around R Sculptoris, in particular the shell mass and temperature, and to constrain the evolution of the mass-loss rate during and after a thermal pulse. Methods. We analyse 12CO(1−0), 12CO(2−1), and 12CO(3−2) emission, observed with the Atacama Large Millimeter/submillimeter Array (ALMA) during Cycle 0 and complemented by single-dish observations. The spatial resolution of the ALMA data allows us to separate the detached shell emission from the extended emission inside the shell. We perform radiative transfer modelling of both components to determine the shell properties and the post-pulse mass-loss properties. Results. The ALMA data show a gas shell with a radius of 19.̋5 expanding at 14.3 km s-1. The different scales probed by the ALMA Cycle 0 array show that the shell must be entirely filled with gas, contrary to the idea of a detached shell. The comparison to single-dish spectra and radiative transfer modelling confirms this. We derive a shell mass of 4.5 × 10-3 M⊙ with a temperature of 50 K. Typical timescales for thermal pulses imply a pulse mass-loss rate of 2.3 × 10-5 M⊙ yr-1. For the post-pulse mass-loss rate, we find evidence for a gradual decline of the mass-loss rate, with an average value of 1.6 × 10-5 M⊙ yr-1. The total amount of mass lost since the last thermal pulse is 0.03 M⊙, a factor four higher compared to classical models, with a sharp decline in mass-loss rate immediately after the pulse. Conclusions. We find that the mass-loss rate after a thermal pulse has to decline more slowly than generally expected from models of thermal pulses. This may cause the star to lose significantly more mass during a thermal pulse cycle, which affects the lifetime on the AGB and the chemical evolution of the star, its circumstellar envelope, and the interstellar medium.
Context.
Flares in radio-loud active galactic nuclei are thought to be associated with the injection of fresh plasma into the compact jet base. Such flares are usually strongest and appear earlier at ...shorter radio wavelengths. Hence, very long baseline interferometry (VLBI) at millimeter(mm)-wavelengths is the best-suited technique for studying the earliest structural changes of compact jets associated with emission flares.
Aims.
We study the morphological changes of the parsec-scale jet in the nearby (
z
= 0.049)
γ
-ray bright radio galaxy 3C 111 following a flare that developed into a major radio outburst in 2007.
Methods.
We analyse three successive observations of 3C 111 at 86 GHz with the Global mm-VLBI Array (GMVA) between 2007 and 2008 which yield a very high angular resolution of ∼45
μ
as. In addition, we make use of single-dish radio flux density measurements from the F-GAMMA and POLAMI programmes, archival single-dish and VLBI data.
Results.
We resolve the flare into multiple plasma components with a distinct morphology resembling a bend in an otherwise remarkably straight jet. The flare-associated features move with apparent velocities of ∼4.0
c
to ∼4.5
c
and can be traced also at lower frequencies in later epochs. Near the base of the jet, we find two bright features with high brightness temperatures up to ∼10
11
K, which we associate with the core and a stationary feature in the jet.
Conclusions.
The flare led to multiple new jet components indicative of a dynamic modulation during the ejection. We interpret the bend-like feature as a direct result of the outburst which makes it possible to trace the transverse structure of the jet. In this scenario, the components follow different paths in the jet stream consistent with expectations for a spine-sheath structure, which is not seen during intermediate levels of activity. The possibility of coordinated multiwavelength observations during a future bright radio flare in 3C 111 makes this source an excellent target for probing the radio-
γ
-ray connection.
Rheumatoid Arthritis (RA) is a chronic inflammatory disease. This study evaluates the effect of blue mussel intake on disease activity and quality of life in women with RA. Thirty-nine women with ...established RA and a disease activity score 28 (DAS28) >3.0 were recruited to a randomized 2 × 11-week cross-over dietary intervention. The participants continued with their medication and habitual diet and exchanged one cooked meal a day, five days a week, with a meal including 75 g blue mussels or 75 g meat. Diets were switched after an eight week washout period. Data regarding quality of life (SF-36), blood lipids, erythrocyte sediment rate (ESR), C-reactive protein (CRP) and tender and swollen joints were examined at the start and end of each dietary period. Thirty women completed one period, and twenty-three completed both. Intake of the blue mussel diet led to a significant reduction of DAS28-CRP (
= 0.048), but not DAS28. The number of EULAR (European League Against Rheumatism) criteria moderate and good responders were higher when consuming blue mussel diet (
= 0.036). Blood lipids did not change. To conclude, blue mussel intake reduced disease symptoms in women with RA and improved perceived health. The reported effects need to be confirmed by non-patient reported outcomes, such as inflammation markers.
Summary
Background
Adverse events leading to discontinuation or dose reduction of thiopurine therapy occur in 9–28% of patients with inflammatory bowel disease.
Aims
To evaluate the influence of ...thiopurine methyltransferase status and thiopurine metabolites in a large patient population for the risk of developing adverse event.
Methods
Three hundred and sixty‐four patients with inflammatory bowel disease and present or previous thiopurine therapy were identified from a local database.
Results
The adverse event observed in 124 patients (34%) were more common in adults than children (40% vs. 15%; P < 0.001) and in low to intermediate (≤9.0 U/mL red blood cell) than normal thiopurine methyltransferase activity (P = 0.02). Myelotoxicity developed later than other types of adverse event. An increased frequency of adverse event was observed in patients with tioguanine (thioguanine) nucleotide above 400 or methylated thioinosine monophosphate above 11 450 pmol/8 × 108 red blood cell. A shift to mercaptopurine was successful in 48% of azathioprine‐intolerant patients and in all cases of azathioprine‐induced myalgia or arthralgia.
Conclusions
A pre‐treatment determination of thiopurine methyltransferase status might be appropriate as patients with low to intermediate thiopurine methyltransferase activity are more prone to develop an adverse event; determination of metabolite levels can be useful in the case of an adverse event. Mercaptopurine therapy should be considered in azathioprine‐intolerant patients.
Context.
The observed orbital characteristics of post-asymptotic giant branch and post-red giant branch (post-RGB) binaries are not understood. We suspect that the missing ingredients needed to ...explain them probably lie in the continuous interaction of the central binary with its circumstellar environment.
Aims.
We aim at studying the circumbinary material in these complex systems by investigating the connection between the innermost structures and large-scale structures.
Methods.
We perform high-angular resolution observations of HD 101584 in the near-infrared continuum. HD 101584 has a complex structure as seen at millimeter wavelengths, with a disk-like morphology and a bipolar outflow due to an episode of a strong binary interaction. To account for the complexity of the target, we first perform an image reconstruction and use this result to fit a geometrical model to extract the morphological and thermal features of the environment.
Results.
The image reveals an unexpected double ring structure. We interpret the inner ring as having been produced by emission from dust located in the plane of the disk, and the outer ring having been produced by emission from dust that is located 1.6 D/1kpc au above the disk plane. The inner ring diameter (3.94 D/1kpc au) and temperature (
T
= 1540 ± 10 K) are compatible with the dust sublimation front of the disk. The origin of the out-of-plane ring (with a diameter of 7.39 D/1kpc au and a temperature of 1014 ± 10 K) could be episodic ejection or a dust condensation front in the outflow.
Conclusions.
The observed outer ring is possibly linked with the blue-shifted side of the large-scale outflow seen by the Atacama Large Millimeter/submillimeter Array and may trace its launching location to the central star. Such observations place morphological constraints on the ejection mechanism. Additional observations are needed to constrain the origin of the out-of-plane structure.
In 2016 September, the microquasar Cygnus X-3 underwent a giant radio flare, which was monitored for 6 d with the Medicina Radio Astronomical Station and the Sardinia Radio Telescope. Long ...observations were performed in order to follow the evolution of the flare on an hourly scale, covering six frequency ranges from 1.5 to 25.6 GHz. The radio emission reached a maximum of 13.2 +/- 0.7 Jy at 7.2 GHz and 10 +/- 1 Jy at 18.6 GHz. Rapid flux variations were observed at high radio frequencies at the peak of the flare, together with rapid evolution of the spectral index: α steepened from 0.3 to 0.6 (with Sν ∝ ν −α) within 5 h. This is the first time that such fast variations are observed, giving support to the evolution from optically thick to optically thin plasmons in expansion moving outward from the core. Based on the Italian network (Noto, Medicina and SRT) and extended to the European antennas (Torun, Yebes, Onsala), very long baseline interferometry (VLBI) observations were triggered at 22 GHz on five different occasions, four times prior to the giant flare, and once during its decay phase. Flux variations of 2 h duration were recorded during the first session. They correspond to a mini-flare that occurred close to the core 10 d before the onset of the giant flare. From the latest VLBI observation we infer that 4 d after the flare peak the jet emission was extended over 30 mas.
Context.
We report the detection of two lines at millimetre wavelengths towards the immediate surroundings of the post-giant and most likely post-common-envelope star HD 101584 using ...high-angular-resolution ALMA observations. The circumstellar environment of this object is rich in different molecular species, but we find no viable identifications in terms of molecular lines.
Aims.
We aim to determine whether or not these lines can be attributed to the Rydberg transitions – X30
α
and X26
α
– of neutral atoms of elements heavier than carbon.
Methods.
A simple model in strict local thermodynamic equilibrium for a warm-gas environment of the moderate-temperature star (
T
eff
≈ 8500 K) was constructed to corroborate our findings. A geometrically thin, disc-like geometry seen face-on was chosen and a distance of 1 kpc.
Results.
The observed flux densities of the lines and the continuum at 232 and 354 GHz can be reproduced using ≈10
−3
M
⊙
of gas at a temperature of ≈2800 K and a hydrogen density of ≈10
12
cm
−3
, assuming solar abundances for the elements. The gas lies within a distance of about 5 au from the star (assuming a distance of 1 kpc). The ionisation fraction is low, ≈3 × 10
−5
. The origin of such a region is not clear, but it may be related to a common-envelope-evolution phase. With these conditions, the line emissions are dominated by Rydberg transitions within the stable isotopes of Mg. A turbulent velocity field in the range 5.5–7.5 km s
−1
is required to fit the Gaussian line shapes. An upper limit to the average magnetic field in the line-emitting region of 1 G is set using the Zeeman effect in these lines.
Conclusions.
We speculate that Rydberg transitions of heavy elements may be an interesting probe for the close-in environments of other moderate-temperature objects like AGB stars, red supergiants, yellow hypergiants, and binaries of various types.
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