41 research outputs found

    Counter-rotation and High-velocity Outflow in the Parsec-scale Molecular Torus of NGC 1068

    Get PDF
    We present 1.4 pc resolution observations of 256 GHz nuclear radio continuum and HCN (J=3→2J=3 \to 2) in the molecular torus of NGC 1068. The integrated radio continuum emission has a flat spectrum consistent with free-free emission and resolves into an X-shaped structure resembling an edge-brightened bicone. HCN is detected in absorption against the continuum, and the absorption spectrum shows a pronounced blue wing that suggests a high-velocity molecular outflow with speeds reaching 450 km/s. Analysis of the off-nucleus emission line kinematics and morphology reveals two nested, rotating disk components. The inner disk, inside r∌1.2r\sim 1.2 pc, has kinematics consistent with the nearly edge-on, geometrically thin water megamaser disk in Keplerian rotation around a central mass of 1.66\times 10^7\,\mbox{M}_\odot. The outer disk, which extends to ∌7\sim 7~pc radius, counter-rotates relative to the inner disk. The rotation curve of the outer disk is consistent with rotation around the same central mass as the megamaser disk but in the opposite sense. The morphology of the molecular gas is asymmetric around the nuclear continuum source. We speculate that the outer disk formed from more recently introduced molecular gas falling out of the host galaxy or from a captured dwarf satellite galaxy. In NGC 1068, we find direct evidence that the molecular torus consists of counter-rotating and misaligned disks on parsec scales.ERC grant 695671 'QUENCH

    “People say men don’t talk, well that’s bullshit”: A focus group study exploring challenges and opportunities for men’s mental health promotion

    Get PDF
    Men’s mental health promotion presents unique challenges including gender-related barriers and stigmas, which demand novel approaches to prevention, treatment, and management. The aim of this study was to explore men’s perceptions of mental health and preferences for mental health promotion. Seven focus groups (N = 59) were conducted in Sydney, Australia, including 5 groups of men (M = 50.65, SD = 13.75 years) and 2 groups of stakeholders who had frontline experience working with men (e.g., men’s groups, health clubs, mental health advocates). Data were analysed using thematic analysis and interpreted using a gender relations approach to explore connections between gender roles, relations and identities, and men’s mental health. Three overarching themes were identified; (1) Roles, identities and the conceptualisation and concealment of mental health challenges, revealing challenges to mental health promotion related to perceptions of men’s restrictive emotionality and emotional awareness as well as difficulties with conceptualising the internalised experiences of mental health, (2) Constraining social contexts of stigma and gender relations, identifying how social context and the policing of gender roles often obscured opportunities for discussing mental health and help-seeking behaviour, (3) Anchoring mental health promotion to acceptable lifestyle practices, highlighting potential remedies included leveraging men’s social practices related to reciprocity, normalising mental health promotion relative to other behaviours, and embedding mental health promotion within acceptable masculine practices. Discussed are directions for men’s community-based mental health promotion and opportunities for how masculinities may be negotiated and expanded to embody mental health promoting values

    Kinetic temperature of massive star-forming molecular clumps measured with formaldehyde IV. The ALMA view of N113 and N159W in the LMC

    Get PDF
    We mapped the kinetic temperature structure of two massive star-forming regions, N113 and N159W, in the Large Magellanic Cloud (LMC). We have used ~1.â€Čâ€Č6 (~0.4 pc) resolution measurements of the para-H2CO JKaKc = 303–202, 322–221, and 321–220 transitions near 218.5 GHz to constrain RADEX non local thermodynamic equilibrium models of the physical conditions. The gas kinetic temperatures derived from the para-H2CO line ratios 322–221/303–202 and 321–220/303–202 range from 28 to 105 K in N113 and 29 to 68 K in N159W. Distributions of the dense gas traced by para-H2CO agree with those of the 1.3 mm dust and Spitzer 8.0 ÎŒm emission, but they do not significantly correlate with the Hα emission. The high kinetic temperatures (Tkin ≳ 50 K) of the dense gas traced by para-H2CO appear to be correlated with the embedded infrared sources inside the clouds and/or young stellar objects in the N113 and N159W regions. The lower temperatures (Tkin < 50 K) were measured at the outskirts of the H2CO-bearing distributions of both N113 and N159W. It seems that the kinetic temperatures of the dense gas traced by para-H2CO are weakly affected by the external sources of the Hα emission. The non thermal velocity dispersions of para-H2CO are well correlated with the gas kinetic temperatures in the N113 region, implying that the higher kinetic temperature traced by para-H2CO is related to turbulence on a ~0.4 pc scale. The dense gas heating appears to be dominated by internal star formation activity, radiation, and/or turbulence. It seems that the mechanism heating the dense gas of the star-forming regions in the LMC is consistent with that in Galactic massive star-forming regions located in the Galactic plane

    Polarimetric properties of Event Horizon Telescope targets from ALMA

    Get PDF
    High Energy Astrophysic

    Resolving the Inner Parsec of the Blazar J1924-2914 with the Event Horizon Telescope

    Get PDF
    The blazar J1924-2914 is a primary Event Horizon Telescope (EHT) calibrator for the Galactic center's black hole Sagittarius A*. Here we present the first total and linearly polarized intensity images of this source obtained with the unprecedented 20 mu as resolution of the EHT. J1924-2914 is a very compact flat-spectrum radio source with strong optical variability and polarization. In April 2017 the source was observed quasi-simultaneously with the EHT (April 5-11), the Global Millimeter VLBI Array (April 3), and the Very Long Baseline Array (April 28), giving a novel view of the source at four observing frequencies, 230, 86, 8.7, and 2.3 GHz. These observations probe jet properties from the subparsec to 100 pc scales. We combine the multifrequency images of J1924-2914 to study the source morphology. We find that the jet exhibits a characteristic bending, with a gradual clockwise rotation of the jet projected position angle of about 90 degrees between 2.3 and 230 GHz. Linearly polarized intensity images of J1924-2914 with the extremely fine resolution of the EHT provide evidence for ordered toroidal magnetic fields in the blazar compact core

    First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole

    Get PDF
    When surrounded by a transparent emission region, black holes are expected to reveal a dark shadow caused by gravitational light bending and photon capture at the event horizon. To image and study this phenomenon, we have assembled the Event Horizon Telescope, a global very long baseline interferometry array observing at a wavelength of 1.3 mm. This allows us to reconstruct event-horizon-scale images of the supermassive black hole candidate in the center of the giant elliptical galaxy M87. We have resolved the central compact radio source as an asymmetric bright emission ring with a diameter of 42 ± 3 ÎŒas, which is circular and encompasses a central depression in brightness with a flux ratio 10:1. The emission ring is recovered using different calibration and imaging schemes, with its diameter and width remaining stable over four different observations carried out in different days. Overall, the observed image is consistent with expectations for the shadow of a Kerr black hole as predicted by general relativity. The asymmetry in brightness in the ring can be explained in terms of relativistic beaming of the emission from a plasma rotating close to the speed of light around a black hole. We compare our images to an extensive library of ray-traced general-relativistic magnetohydrodynamic simulations of black holes and derive a central mass of M = (6.5 ± 0.7) × 109 Me. Our radiowave observations thus provide powerful evidence for the presence of supermassive black holes in centers of galaxies and as the central engines of active galactic nuclei. They also present a new tool to explore gravity in its most extreme limit and on a mass scale that was so far not accessible
    corecore