3,367 research outputs found

    The dense molecular gas in the z∼6\rm z\sim6 QSO SDSS J231038.88+185519.7 resolved by ALMA

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    We present ALMA observations of the CO(6-5) and [CII] emission lines and the sub-millimeter continuum of the z∼6z\sim6 quasi-stellar object (QSO) SDSS J231038.88+185519.7. Compared to previous studies, we have analyzed a synthetic beam that is ten times smaller in angular size, we have achieved ten times better sensitivity in the CO(6-5) line, and two and half times better sensitivity in the [CII] line, enabling us to resolve the molecular gas emission. We obtain a size of the dense molecular gas of 2.9±0.52.9\pm0.5 kpc, and of 1.4±0.21.4\pm0.2 kpc for the 91.5 GHz dust continuum. By assuming that CO(6-5) is thermalized, and by adopting a CO--to--H2H_2 conversion factor αCO=0.8 M⊙ K−1 (km/s)−1 pc2\rm \alpha_{CO} = 0.8~ M_{\odot}~K^{-1}~ (km/s)^{-1} ~pc^{2}, we infer a molecular gas mass of M(H2)=(3.2±0.2)×1010M⊙\rm M(H_2)=(3.2 \pm0.2) \times 10^{10}\rm M_{\odot}. Assuming that the observed CO velocity gradient is due to an inclined rotating disk, we derive a dynamical mass of Mdyn sin2(i)=(2.4±0.5)×1010 M⊙\rm M_{dyn}~sin^2(i) = (2.4\pm0.5) \times 10^{10}~ M_{\odot}, which is a factor of approximately two smaller than the previously reported estimate based on [CII]. Regarding the central black hole, we provide a new estimate of the black hole mass based on the C~IV emission line detected in the X-SHOOTER/VLT spectrum: MBH=(1.8±0.5)×109 M⊙\rm M_{BH}=(1.8\pm 0.5) \times 10^{9}~ M_{\odot}. We find a molecular gas fraction of μ=M(H2)/M∗∼4.4\rm \mu=M(H_2)/M^*\sim4.4, where M∗≈Mdyn−M(H2)−M(BH)\rm M^*\approx M_{dyn} - M(H_2)-M(BH). We derive a ratio vrot/σ≈1−2v_{rot}/\sigma \approx 1-2 suggesting high gas turbulence, outflows/inflows and/or complex kinematics due to a merger event. We estimate a global Toomre parameter Q∼0.2−0.5Q\sim 0.2-0.5, indicating likely cloud fragmentation. We compare, at the same angular resolution, the CO(6-5) and [CII] distributions, finding that dense molecular gas is more centrally concentrated with respect to [CII]. We find that the current BH growth rate is similar to that of its host galaxy.Comment: A&A in pres

    Speed limits for radiation-driven SMBH winds

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    Context. Ultra-fast outflows (UFOs) have become an established feature in analyses of the X-ray spectra of active galactic nuclei (AGN). According to the standard picture, they are launched at accretion disc scales with relativistic velocities, up to 0.3-0.4 times the speed of light. Their high kinetic power is enough to induce an efficient feedback on a galactic scale, possibly contributing to the co-evolution between the central supermassive black hole (SMBH) and the host galaxy. It is, therefore, of paramount importance to gain a full understanding of UFO physics and, in particular, of the forces driving their acceleration and the relation to the accretion flow from which they originate.Aims. In this paper, we investigate the impact of special relativity effects on the radiative pressure exerted onto the outflow. The radiation received by the wind decreases for increasing outflow velocity, v, implying that the standard Eddington limit argument has to be corrected according to v. Due to the limited ability of the radiation to counteract the black hole gravitational attraction, we expect to find lower typical velocities with respect to the non-relativistic scenario.Methods. We integrated the relativistic-corrected outflow equation of motion for a realistic set of starting conditions. We concentrated on a range of ionisations, column densities, and launching radii consistent with those typically estimated for UFOs. We explore a one-dimensional, spherical geometry and a three-dimensional setting with a rotating, thin accretion disc.Results. We find that the inclusion of special relativity effects leads to sizeable differences in the wind dynamics and that v is reduced up to 50% with respect to the non-relativistic treatment. We compare our results with a sample of UFOs from the literature and we find that the relativistic-corrected velocities are systematically lower than the reported ones, indicating the need for an additional mechanism, such as magnetic driving, to explain the highest velocity components. Finally, we note that these conclusions, derived for AGN winds, are generally applicable

    On the importance of special relativistic effects in modelling ultra-fast outflows

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    Outflows are observed in a variety of astrophysical sources. Remarkably, ultra-fast (v≥0.1cv\geq 0.1c), outflows in the UV and X-ray bands are often seen in AGNs. Depending on their energy and mass outflow rate, respectively E˙out,M˙out\dot{E}_{out}, \dot{M}_{out}, such outflows may play a key role in regulating the AGN-host galaxy co-evolution process through cosmic time. It is therefore crucial to provide accurate estimates of the wind properties. Here, we concentrate on special relativistic effects concerning the interaction of light with matter moving at relativistic speed relatively to the source of radiation. Our aim is to assess the impact of these effects on the observed properties of the outflows and implement a relativistic correction in the existing spectral modelling routines. We define a simple procedure to incorporate relativistic effects in radiative transfer codes. Following this procedure, we run a series of simulations to explore the impact of these effects on the simulated spectra, for different vv and column densities of the outflow. The observed optical depth is usually considered a proxy for the wind NHN_H, independently on its velocity. However, our simulations show that the observed optical depth of an outflow with a given column density NHN_H decreases rapidly as the velocity of the wind approaches relativistic values. This, in turn, implies that when estimating NHN_H from the optical depth, it is necessary to include a velocity-dependent correction, already for moderate velocities (e.g. v≥0.05cv \geq 0.05c). This correction linearly propagates to the derived M˙out,E˙out\dot{M}_{out}, \dot{E}_{out}. As an example of these effects, we calculate the relativistically corrected values of M˙out\dot{M}_{out} and E˙out\dot{E}_{out} for a sample of ∼30\sim 30 Ultra-Fast Outflows taken from the literature, and find correction factors of 20−120%20-120 \% within the observed range of outflowing velocities.Comment: 6 pages, 5 figures. Accepted for publication in A&

    A multicenter retrospective clinical study of CD5/CD10-negative chronic B cell leukemias.

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    CD5-negative chronic B cell lymphoproliferative disorders in leukemic phase (B-CLPD) are heterogeneous and relatively uncommon pathologies that often lack a histopathological definition because of the absence of accessible pathological tissue. We describe the clinical features and evolution-related variables of 156 patients with CD5/CD10-negative B-CLPD (median age 66 years, range 25-86). The median follow-up was 51 months (range 6-216), and overall 3- and 5-year survival was respectively 87 and 76%; 50 patients needed therapy at diagnosis, 56 during follow-up, and 50 remained untreated until the last control. A combined clinical, histological, cytomorphological, immunophenotypical, and cytogenetic diagnostic approach allowed the complete classification of only a minority of patients as being affected by splenic marginal zone or lymphoplasmacytic lymphoma; the majority of cases remained unclassifiable. Multivariate analysis showed that the clinicohematological variables adversely related to overall survival were serum LDH levels and age, whereas high serum LDH levels, hemoglobin levels of <11 g/dl, and splenomegaly related to treatment-free time (in "wait and see" cases); only splenomegaly related to time to progression (in treated patients). In conclusion, our retrospective study describes the clinical features and variables related to evolution in a large group of patients with CD5/CD10-negative chronic B-cell lymphoid leukemias and underlines the fact that a probable lymphoplasmacytic or marginal zone normal cell origin can be supposed in such leukemic forms, but never surely demonstrated

    ABVD plus radiotherapy versus EVE plus radiotherapy in unfavorable stage IA and IIA Hodgkin's lymphoma: results from an Intergruppo Italiano Linfomi randomized study.

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    BACKGROUND: In 1997, the Intergruppo Italiano Linfomi started a randomized trial to evaluate, in unfavorable stage IA and IIA Hodgkin's lymphoma (HL) patients, the efficacy and toxicity of the low toxic epirubicin, vinblastine and etoposide (EVE) regimen followed by involved field radiotherapy in comparison to the gold standard doxorubicin, bleomycin, vinblastine and dacarbazine (ABVD) regimen followed by the same radiotherapy program. PATIENTS AND METHODS: Patients should be younger than 65 years with unfavorable stage IA and IIA HL (i.e. stage IA or IIA with bulky disease and/or subdiaphragmatic disease, erythrocyte sedimentation rate higher than 40, extranodal (E) involvement, hilar involvement and more than three involved lymph node areas). RESULTS: Ninety-two patients were allocated to the ABVD arm and 89 to the EVE arm. Complete remission (CR) rates at the end of treatment program [chemotherapy (CT) + RT] were 93% and 92% for ABVD and EVE arms, respectively (P = NS). The 5-year relapse-free survival (RFS) rate was 95% for ABVD and 78% for EVE (P < 0.05). As a consequence of the different relapse rate, the 5-year failure-free survival (FFS) rate was significantly better for ABVD (90%) than for EVE (73%) arm (P < 0.05). No differences in terms of overall survival (OS) were observed for the two study arms. CONCLUSIONS: In unfavorable stage IA and IIA HL patients, no differences were observed between ABVD and EVE arms in terms of CR rate and OS. EVE CT, however, was significantly worse than ABVD in terms of RFS and FFS and cannot be recommended as initial treatment for HL

    Prevalence and distribution of vascular calcifications at CT scan in patients with and without large vessel vasculitis: A matched cross-sectional study

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    Objectives The aim of this study was to compare the prevalence, entity and local distribution of arterial wall calcifications evaluated on CT scans in patients with large vessel vasculitis (LVV) and patients with lymphoma as reference for the population without LVV. Methods All consecutive patients diagnosed with LVVs with available baseline positron emission tomography-CT (PET-CT) scan performed between 2007 and 2019 were included; non-LVV patients were lymphoma patients matched by age (±5 years), sex and year of baseline PET-CT (≤2013; &gt;2013). CT images derived from baseline PET-CT scans of both patient groups were retrospectively reviewed by a single radiologist who, after setting a threshold of minimum 130 Hounsfield units, semiautomatically computed vascular calcifications in three separate locations (coronaries, thoracic and abdominal arteries), quantified as Agatston and volume scores. Results A total of 266 patients were included. Abdominal artery calcifications were equally distributed (mean volume 3220 in LVVs and 2712 in lymphomas). Being in the LVVs group was associated with the presence of thoracic calcifications after adjusting by age and year of diagnosis (OR 4.13, 95% CI 1.35 to 12.66; p=0.013). Similarly, LVVs group was significantly associated with the volume score in the thoracic arteries (p=0.048). In patients &gt;50 years old, calcifications in the coronaries were more extended in non-LVV patients (p=0.027 for volume). Conclusion When compared with patients without LVVs, LVVs patients have higher calcifications in the thoracic arteries, but not in coronary and abdominal arteries

    The Muon Spectrometer Barrel Level-1 Trigger of the ATLAS Experiment at LHC

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    The proton-proton beam crossing at the LHC accelerator at CERN will have a rate of 40 MHz at the project luminosity. The ATLAS Trigger System has been designed in three levels in order to select only interesting physics events reducing from that rate of 40 MHz to the foreseen storage rate of about 200 Hz. The First Level reduces the output rate to about 100 kHz. The ATLAS Muon Spectrometer has been designed to perform stand-alone triggering and measurement of muon transverse momentum up to 1 TeV/c with good resolution (from 3% at 10 GeV/c up to 10% at 1 TeV/c). In the Barrel region of the Muon Spectrometer the Level-1 trigger is given by means of three layers of Resistive Plate Chamber detectors (RPC): a gaseous detector working in avalanche mode composed by two plates of high-resistivity bakelite and two orthogonal planes of read-out strips. The logic of the Level-1 barrel muon trigger is based on the search of patterns of RPC hits in the three layers consistent with a high transverse momentum muon track originated from the interaction vertex. The associated trigger electronics is based on dedicated processors, the Coincidence Matrix boards, performing space coincidences and time gates and providing the RPC readout as well. A detailed simulation of the ATLAS Experiment and of both the hardware components and the logic of the Level-1 Muon Trigger in the barrel of the Muon Spectrometer has been performed. This simulation has been used not only to evaluate the performances of the system but also to define the hardware set-up such as the cabling of both the trigger detectors and the trigger electronics modules. A description of both the Level-1 Muon Trigger system in the barrel and the RPC detectors, with their cosmic rays quality tests, will be presented together with the trigger performances and rates calculations evaluated for muons over a wide range of pT and preliminary studies on the impact of accidental triggers due to low energy background particles in the experimental area

    The use of FDG-PET in the initial staging of 142 patients with follicular lymphoma: a retrospective study from the FOLL05 randomized trial of the Fondazione Italiana Linfomi

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    BACKGROUND: The role of [(18)F] fluorodeoxyglucose (FDG)-positron emission tomography (PET) in follicular lymphoma (FL) staging is not yet determined. PATIENTS AND METHODS: The aim of the present study was to investigate the role of PET in the initial staging of FL patients enrolled in the FOLL05-phase-III trial that compared first-line regimens (R-CVP, R-CHOP and R-FM). Patients should have undergone conventional staging and have available PET baseline to be included. RESULTS: A total of 142 patients were analysed. PET identified a higher number of nodal areas in 32% (46 of 142) of patients and more extranodal (EN) sites than computed tomography (CT) scan. Also, the Follicular Lymphoma International Prognostic Index (FLIPI) score increased in 18% (26 of 142) and decreased in 6% (9 of 142) of patients. Overall, the impact of PET on modifying the stage was highest in patients with limited stage. Actually, 62% (15 of 24) of cases with limited disease were upstaged with PET. CONCLUSIONS: The inclusion of PET among staging procedures makes the evaluation of patients with FL more accurate and has the potential to modify therapy decision and prognosis in a moderate proportion of patients. Further prospective clinical trials on FL should incorporate PET at different moments, and the therapeutic criteria to start therapy should be re-visited in the views of this new tool
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