729 research outputs found

    Unification of X-ray winds in Seyfert galaxies: from ultra-fast outflows to warm absorbers

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    The existence of ionized X-ray absorbing layers of gas along the line of sight to the nuclei of Seyfert galaxies is a well established observational fact. This material is systematically outflowing and shows a large range in parameters. However, its actual nature and dynamics are still not clear. In order to gain insights into these important issues we performed a literature search for papers reporting the parameters of the soft X-ray warm absorbers (WAs) in 35 type 1 Seyferts and compared their properties to those of the ultra-fast outflows (UFOs) detected in the same sample. The fraction of sources with WAs is >60%, consistent with previous studies. The fraction of sources with UFOs is >34%, >67% of which also show WAs. The large dynamic range obtained when considering all the absorbers together allows us, for the first time, to investigate general relations among them. In particular, we find significant correlations indicating that the closer the absorber is to the central black hole, the higher the ionization, column, outflow velocity and consequently the mechanical power. The absorbers continuously populate the whole parameter space, with the WAs and the UFOs lying always at the two ends of the distribution. This strongly suggest that these absorbers, often considered of different types, could actually represent parts of a single large-scale stratified outflow observed at different locations from the black hole. The observed parameters and correlations are consistent with both radiation pressure through Compton scattering and MHD processes contributing to the outflow acceleration, the latter playing a major role. Most of the absorbers, especially the UFOs, have a sufficiently high mechanical power to significantly contribute to AGN feedback.Comment: Manuscript updated to match the MNRAS published version. Link to the related INAF news: http://www.media.inaf.it/2013/02/05/warm-absorbers

    Digging for red nuggets: Discovery of hot haloes surrounding massive, compact, relic galaxies

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    We present the results of Chandra X-ray observations of the isolated, massive, compact, relic galaxies MRK 1216 and PGC 032873. Compact massive galaxies observed at z > 2, also called red nuggets, formed in quick dissipative events and later grew by dry mergers into the local giant ellipticals. Due to the stochastic nature of mergers, a few of the primordial massive galaxies avoided the mergers and remained untouched over cosmic time.We find that the hot atmosphere surrounding MRK 1216 extends far beyond the stellar population and has a 0.5-7 keV X-ray luminosity of LX = (7.0 ± 0.2) × 1041 erg s-1, which is similar to the nearby X-ray bright giant ellipticals. The hot gas has a short central cooling time of ~50 Myr and the galaxy has an ~13-Gyr-old stellar population. The presence of an X-ray atmosphere with a short nominal cooling time and the lack of young stars indicate the presence of a sustained heating source, which prevented star formation since the dissipative origin of the galaxy 13 Gyr ago. The central temperature peak and the presence of radio emission in the core of the galaxy indicate that the heating source is radio-mechanical active galactic nucleus (AGN) feedback. Given that both MRK 1216 and PGC 032873 appear to have evolved in isolation, the order of magnitude difference in their current X-ray luminosity could be traced back to a difference in the ferocity of the AGN outbursts in these systems. Finally, we discuss the potential connection between the presence of hot haloes around such massive galaxies and the growth of super-/overmassive black holes via chaotic cold accretion. © 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society

    Laparoscopic single-port sleeve gastrectomy for morbid obesity: preliminary series

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    Laparoscopic sleeve gastrectomy has been recently proposed as a sole bariatric procedure because of the resulting considerable weight loss in morbidly obese patients. Traditionally, laparoscopic sleeve gastrectomy requires 5-6 skin incisions to allow for placement of multiple trocars. With the introduction of single-incision laparoscopic surgery, multiple abdominal procedures have been performed using a sole umbilical incision, with good cosmetic outcomes. The purpose of our study was to evaluate the feasibility and safety of laparoscopic single incision sleeve gastrectomy for morbid obesity

    Expressão gênica em grãos de café submetidos a diferentes tratamentos pós-colheita-uma análise preliminar.

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    O conhecimento sobre como os tipos de processamento pós-colheita interferem na qualidade final de bebida é essencial para que cafés com qualidades especiais possam ser desenvolvidos. Dentre as características que podem ser diretamente influenciadas pelo processamento, a composição química do grão é a de maior interesse. Fatores como a regulação da expressão de genes e a atividade de enzimas específicas são determinantes para esta composição. Neste contexto, o objetivo deste estudo preliminar foi avaliar como os processamentos por via seca e úmida afetam o padrão de expressão dos genes isocitrato liase (ICL), ?-mananase (MAN) e ?-galactosidase (GAL). Frutos cereja foram submetidos a condições de secagem natural, despolpamento e desmucilamento. A expressão dos genes foi quantificada pela metodologia de RT-PCR em tempo real. A análise comparativa da expressão dos 3 genes indicou que no processamento via seca a expressão de ICL e MAN nas sementes foi maior do que em sementes de frutos processados por via úmida. Para o gene GAL, não foram observadas diferenças expressivas no perfil de expressão em sementes dos frutos submetidos aos diferentes tratamentos. Esses resultados diferiram dos obtidos em outros estudos já descritos na literatura, em que, apesar de ter sido avaliada a expressão de genes, foram utilizadas etapas de processamento distintas das utilizadas neste trabalho. Esses resultados revelaram, portanto, que há necessidade de se padronizarem os processamentos experimentais em pesquisas visando avaliar efeitos dos tratamentos pós-colheita sobre a qualidade do café

    Produção de anticorpos monoclonais anti-cisticercos de Taenia crassiceps com reatividade cruzada com antígenos de Taenia solium

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    We describe the production of the potential monoclonal antibodies (MoAbs) using BALB/c mice immunized with vesicular fluid (VF)-Tcra (T. crassiceps) antigen. Immune sera presented anti-VF-Tcra (É descrita a produção de potenciais anticorpos monoclonais (MoAbs) usando camundongos BALB/c imunizados com antígenos de líquido vesicular de T. crassiceps (VF-Tcra). O soro imune apresentou anticorpos IgM e IgG anti-VF-Tcra para os peptídeo

    Cooling in the X-ray halo of the rotating, massive early-type galaxy NGC 7049

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    The relative importance of the physical processes shaping the thermodynamics of the hot gas permeating rotating, massive early-type galaxies is expected to be different from that in non-rotating systems. Here, we report the results of the analysis of XMM-Newton data for the massive, lenticular galaxy NGC 7049. The galaxy harbours a dusty disc of cool gas and is surrounded by an extended hot X-ray emitting gaseous atmosphere with unusually high central entropy. The hot gas in the plane of rotation of the cool dusty disc has a multi-temperature structure, consistent with ongoing cooling. We conclude that the rotational support of the hot gas is likely capable of altering the multiphase condensation regardless of the tcool/tfft_{\rm cool}/t_{\rm ff} ratio, which is here relatively high, 40\sim 40. However, the measured ratio of cooling time and eddy turnover time around unity (CC-ratio 1\approx 1) implies significant condensation, and at the same time, the constrained ratio of rotational velocity and the velocity dispersion (turbulent Taylor number) Tat>1{\rm Ta_t} > 1 indicates that the condensing gas should follow non-radial orbits forming a disc instead of filaments. This is in agreement with hydrodynamical simulations of massive rotating galaxies predicting a similarly extended multiphase disc.Comment: 11 pages, 12 figures, accepted for publication in MNRA

    Evidence for ultra-fast outflows in radio-quiet AGNs: III - location and energetics

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    Using the results of a previous X-ray photo-ionization modelling of blue-shifted Fe K absorption lines on a sample of 42 local radio-quiet AGNs observed with XMM-Newton, in this letter we estimate the location and energetics of the associated ultra-fast outflows (UFOs). Due to significant uncertainties, we are essentially able to place only lower/upper limits. On average, their location is in the interval ~0.0003-0.03pc (~10^2-10^4 r_s) from the central black hole, consistent with what is expected for accretion disk winds/outflows. The mass outflow rates are constrained between ~0.01-1 M_{\odot} yr^{-1}, corresponding to >5-10% of the accretion rates. The average lower-upper limits on the mechanical power are log\dot{E}_K~42.6-44.6 erg s^{-1}. However, the minimum possible value of the ratio between the mechanical power and bolometric luminosity is constrained to be comparable or higher than the minimum required by simulations of feedback induced by winds/outflows. Therefore, this work demonstrates that UFOs are indeed capable to provide a significant contribution to the AGN cosmological feedback, in agreement with theoretical expectations and the recent observation of interactions between AGN outflows and the interstellar medium in several Seyferts galaxies.Comment: 5 pages, 3 figures, accepted for publication in MNRA

    Cosmological hydrodynamical simulations of galaxy clusters: X-ray scaling relations and their evolution

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    We analyse cosmological hydrodynamical simulations of galaxy clusters to study the X-ray scaling relations between total masses and observable quantities such as X-ray luminosity, gas mass, X-ray temperature, and YXY_{X}. Three sets of simulations are performed with an improved version of the smoothed particle hydrodynamics GADGET-3 code. These consider the following: non-radiative gas, star formation and stellar feedback, and the addition of feedback by active galactic nuclei (AGN). We select clusters with M500>1014ME(z)1M_{500} > 10^{14} M_{\odot} E(z)^{-1}, mimicking the typical selection of Sunyaev-Zeldovich samples. This permits to have a mass range large enough to enable robust fitting of the relations even at z2z \sim 2. The results of the analysis show a general agreement with observations. The values of the slope of the mass-gas mass and mass-temperature relations at z=2z=2 are 10 per cent lower with respect to z=0z=0 due to the applied mass selection, in the former case, and to the effect of early merger in the latter. We investigate the impact of the slope variation on the study of the evolution of the normalization. We conclude that cosmological studies through scaling relations should be limited to the redshift range z=01z=0-1, where we find that the slope, the scatter, and the covariance matrix of the relations are stable. The scaling between mass and YXY_X is confirmed to be the most robust relation, being almost independent of the gas physics. At higher redshifts, the scaling relations are sensitive to the inclusion of AGNs which influences low-mass systems. The detailed study of these objects will be crucial to evaluate the AGN effect on the ICM.Comment: 24 pages, 11 figures, 5 tables, replaced to match accepted versio

    Mass\u2013metallicity relation from cosmological hydrodynamical simulations and X-ray observations of galaxy groups and clusters

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    Recent X-ray observations of galaxy clusters show that the distribution of intra-cluster medium (ICM) metallicity is remarkably uniform in space and time. In this paper, we analyse a large sample of simulated objects, from poor groups to rich clusters, to study the dependence of the metallicity and related quantities on the mass of the systems. The simulations are performed with an improved version of the smoothed-particle-hydrodynamic GADGET-3 code and consider various astrophysical processes including radiative cooling, metal enrichment and feedback from stars and active galactic nuclei (AGNs). The scaling between the metallicity and the temperature obtained in the simulations agrees well in trend and evolution with the observational results obtained from two data samples characterized by a wide range of masses and a large redshift coverage. We find that the iron abundance in the cluster core (r < 0.1R500) does not correlate with the temperature nor presents a significant evolution. The scale invariance is confirmed when the metallicity is related directly to the total mass. The slope of the best-fitting relations is shallow (\u3b2 \u2dc -0.1) in the innermost regions (r < 0.5R500) and consistent with zero outside. We investigate the impact of the AGN feedback and find that it plays a key role in producing a constant value of the outskirts metallicity from groups to clusters. This finding additionally supports the picture of early enrichment

    Role of 0.4% glyceryl trinitrate ointment after haemorrhoidectomy: results of a prospective randomised study

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    INTRODUCTION: Conventional haemorrhoidectomy (CH) is well known to cause significant post-operative pain and delayed return to daily activities. Both surgical wounds and sphincterial apparatus spasms are likely responsible for the pain. In this study, we evaluated the role of glyceryl trinitrate ointment (GTN) in reducing post-operative pain, ameliorating wound healing and recovery after CH. PATIENTS AND METHODS: Between 01/08 and 12/11, 203 patients with symptomatic haemorrhoids were enrolled in the study and received (103 patients) or not (100 patients) 0.4 % GTN ointment for 6 weeks after surgery. Pain was assessed using a 10-cm linear visual analogue scale (VAS). Data on post-operative pain, wound secretion and bleeding, return to normal activities and complications were recorded. Data were analysed using Fisher's exact and Mann-Whitney tests. RESULTS: GTN-treated group experienced significantly less pain during the first week after surgery (p < 0.0001). This difference was more evident starting from post-operative day 4 (p < 0.0001). A significant higher percentage of untreated patients experienced severe pain (mean VAS score > 7) (10 % vs 31 %). There were significant differences in terms of secretion time (p = 0.0052) and bleeding time (p = 0.02) in favor of GTN. In addition, the duration of itching was less in the GTN group (p = 0.0145). Patients treated with GTN were able to an early return to daily activities compared to untreated (p < 0.0001). Fifteen GTN-treated patients (14.6 %) discontinued the application because of local discomfort and headache. CONCLUSIONS: GTN ointment enhances significantly post-operative recovery, reducing pain in terms of duration and intensity. This effect might be secondary to a faster wound healing expressed by reduced secretion, bleeding and itching time
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