50 research outputs found

    Adolescent Risk Behaviors and Religion: Findings from a National Study

    Get PDF
    Too few studies have assessed the relationship between youth risk behaviors and religiosity using measures which captured the varied extent to which youth are engaged in religion. This study applied three measures of religiosity and risk behaviors. In addition, this study ascertained information about youths’ participation in religious activities from a parent or caretaker. Based on a national random sample of 2,004 teens (ages 11-18), this study indicates that youth perceive religion as important, are active in religious worship and activities, and further shows that perceived importance of religion as well as participation in religious activities are associated with decreased risk behaviors. Looking at ten risk behaviors, religiosity variables were consistently associated with reduced risk behaviors in the areas of: smoking, alcohol use, truancy, sexual activity, marijuana use, and depression. In the case of these six risk variables, religiosity variables were significantly associated with reduced risk behaviors when controlling for family background variables and self esteem. The study highlights the importance of further understanding the relationship between religious variables, background variables, self esteem, and youth risk behaviors

    Youth and Religion: The Gameboy Generation Goes to Church

    Get PDF
    Using the secularization theory and the Marxist notion of religion as masking class conscience one would expect the importance of religion and religious involvement today to wane and be limited to lower class members. To challenge this expectation, using a representative national telephone survey of 2004 youth (ages 11–18) and their parents, we attempt to answer the following two questions: How religious are teenagers, and what may explain variation in religious perception and involvement among teens. Findings suggest that religion remains perceived as very important by most teenagers and parents report that about two-thirds of teenagers attended a place of worship at least monthly and that two out of five attended a social group sponsored by a religious organization. These findings do not support the secularization theory. As expected, parental attendance of religious worship, teen’s age, and teen’s ethnicity and gender were significantly associated with three variables of religious behavior and attendance. In contrast to the Marxist notion of religion, measures of socio-economic status indicate that, in the contemporary United States, religious participation, but not beliefs, is largely the domain of the middle-upper classes

    The Polarized Image of a Synchrotron-emitting Ring of Gas Orbiting a Black Hole

    Get PDF
    Abstract: Synchrotron radiation from hot gas near a black hole results in a polarized image. The image polarization is determined by effects including the orientation of the magnetic field in the emitting region, relativistic motion of the gas, strong gravitational lensing by the black hole, and parallel transport in the curved spacetime. We explore these effects using a simple model of an axisymmetric, equatorial accretion disk around a Schwarzschild black hole. By using an approximate expression for the null geodesics derived by Beloborodov and conservation of the Walker–Penrose constant, we provide analytic estimates for the image polarization. We test this model using currently favored general relativistic magnetohydrodynamic simulations of M87*, using ring parameters given by the simulations. For a subset of these with modest Faraday effects, we show that the ring model broadly reproduces the polarimetric image morphology. Our model also predicts the polarization evolution for compact flaring regions, such as those observed from Sgr A* with GRAVITY. With suitably chosen parameters, our simple model can reproduce the EVPA pattern and relative polarized intensity in Event Horizon Telescope images of M87*. Under the physically motivated assumption that the magnetic field trails the fluid velocity, this comparison is consistent with the clockwise rotation inferred from total intensity images

    The polarized image of a synchrotron-emitting ring of gas orbiting a black hole

    Get PDF
    Synchrotron radiation from hot gas near a black hole results in a polarized image. The image polarization is determined by effects including the orientation of the magnetic field in the emitting region, relativistic motion of the gas, strong gravitational lensing by the black hole, and parallel transport in the curved spacetime. We explore these effects using a simple model of an axisymmetric, equatorial accretion disk around a Schwarzschild black hole. By using an approximate expression for the null geodesics derived by Beloborodov and conservation of the Walker–Penrose constant, we provide analytic estimates for the image polarization. We test this model using currently favored general relativistic magnetohydrodynamic simulations of M87*, using ring parameters given by the simulations. For a subset of these with modest Faraday effects, we show that the ring model broadly reproduces the polarimetric image morphology. Our model also predicts the polarization evolution for compact flaring regions, such as those observed from Sgr A* with GRAVITY. With suitably chosen parameters, our simple model can reproduce the EVPA pattern and relative polarized intensity in Event Horizon Telescope images of M87*. Under the physically motivated assumption that the magnetic field trails the fluid velocity, this comparison is consistent with the clockwise rotation inferred from total intensity images.http://iopscience.iop.org/0004-637Xam2023Physic

    Event Horizon Telescope observations of the jet launching and collimation in Centaurus A

    Get PDF
    Abstract: Very-long-baseline interferometry (VLBI) observations of active galactic nuclei at millimetre wavelengths have the power to reveal the launching and initial collimation region of extragalactic radio jets, down to 10–100 gravitational radii (rg ≡ GM/c2) scales in nearby sources1. Centaurus A is the closest radio-loud source to Earth2. It bridges the gap in mass and accretion rate between the supermassive black holes (SMBHs) in Messier 87 and our Galactic Centre. A large southern declination of −43° has, however, prevented VLBI imaging of Centaurus A below a wavelength of 1 cm thus far. Here we show the millimetre VLBI image of the source, which we obtained with the Event Horizon Telescope at 228 GHz. Compared with previous observations3, we image the jet of Centaurus A at a tenfold higher frequency and sixteen times sharper resolution and thereby probe sub-lightday structures. We reveal a highly collimated, asymmetrically edge-brightened jet as well as the fainter counterjet. We find that the source structure of Centaurus A resembles the jet in Messier 87 on ~500 rg scales remarkably well. Furthermore, we identify the location of Centaurus A’s SMBH with respect to its resolved jet core at a wavelength of 1.3 mm and conclude that the source’s event horizon shadow4 should be visible at terahertz frequencies. This location further supports the universal scale invariance of black holes over a wide range of masses5, 6
    corecore