3,700 research outputs found

    The nature of the ultraluminous X-ray sources inside galaxies and their relation to local QSOs

    Get PDF
    It is suggested that many of the ultraluminous compact x-ray sources now being found in the main bodies of galaxies, particularly those that are active, like M82, NGC 3628 and others, are "local" QSOs, or BL Lac objects, with high intrinsic redshifts in the process of being ejected from those galaxies. Evidence in support of this hypothesis is summarized.Comment: submitted to A&A Letter

    Ionized gas in the nuclei of elliptical, so, spiral, and irregular galaxies

    Get PDF
    Ionized gas in elliptical, SO, spiral, and irregular galaxy nucle

    The Nature of the Quasi-stellar Objects

    Get PDF
    Quasi-stellar objects analyzed stressing theory of local versus cosmological phenomeno

    Phase Locked Loop Test Methodology

    Get PDF
    Phase locked loops are incorporated into almost every large-scale mixed signal and digital system on chip (SOC). Various types of PLL architectures exist including fully analogue, fully digital, semi-digital, and software based. Currently the most commonly used PLL architecture for SOC environments and chipset applications is the Charge-Pump (CP) semi-digital type. This architecture is commonly used for clock synthesis applications, such as the supply of a high frequency on-chip clock, which is derived from a low frequency board level clock. In addition, CP-PLL architectures are now frequently used for demanding RF (Radio Frequency) synthesis, and data synchronization applications. On chip system blocks that rely on correct PLL operation may include third party IP cores, ADCs, DACs and user defined logic (UDL). Basically, any on-chip function that requires a stable clock will be reliant on correct PLL operation. As a direct consequence it is essential that the PLL function is reliably verified during both the design and debug phase and through production testing. This chapter focuses on test approaches related to embedded CP-PLLs used for the purpose of clock generation for SOC. However, methods discussed will generally apply to CP-PLLs used for other applications

    Theoretical Ideas Concerning X-ray Sources

    Get PDF
    Black body radiation, inverse Compton effect, thermal brehmsstrahlung, and synchrotron radiation which may give rise to hard proton

    Ultraviolet emission from galaxies

    Get PDF
    Ultraviolet radiation emission from normal elliptical, spiral, and irregular galaxie

    X-ray Bright QSO's around NGC 3079

    Full text link
    NGC 3079 is a very active, disturbed galaxy which has been observed to have X-ray and radio ejections from it as well as an optical superbubble along its minor axis. Here we show that the brightest X-ray sources within about 40 arcmin are in large excess of background values. The X-ray sources are identified as quasars and AGN's which are aligned and spaced across the Seyfert nucleus to a degree which is unlikely to be due to chance. The famous double quasar which has been interpreted as a gravitational lens is discussed in terms of the the X - ray and ULX sources which appear associated with NGC 3079.Comment: 6 figures, submitted to Ap

    Capital Tax Competition and Returns to Scale

    Get PDF
    There is a gap between the predictions of capital tax competition models and the reality they purport to describe. In a standard capital-tax model, with head taxes, capital-importing regions tax capital and capital-exporting regions subsidize capital. In the real-world, competing regions appear to subsidize capital whether or not they are capital importers. We show that by relaxing the standard assumption of constant returns to scale symmetric regions in a Nash equilibrium may all subsidize capital.We also prove that any ine±ciencies in a non-symmetric Nash equilibria arise entirely from regions’ incentives to manipulate the terms of trade, and not from increasing returns.We also compare our results to those in captial tax competition models without head taxes.

    Portable Gamma Spectrometry Surveys of Sites in Portugal in Support of the VADOSE Project

    Get PDF
    The VADOSE project involves the use of multiple techniques to evaluate dose rate variability on different spatial scales. Several sites in central northern Portugal, mostly in the vicinity of Aveiro, have been investigated. As part of this investigation, portable gamma spectrometry techniques were used to map areas of approximately 100x100m around each sampling location. The SUERC portable gamma spectrometry system used consists of a 3x3” NaI(Tl) spectrometer with integral GPS receiver. Measurements were conducted with 10s integration time. Maps of the dose rate variability in each area were generated in the field, and used to confirm data quality and coverage and identify any remaining locations that would benefit from further measurements prior to leaving the site. Maps of natural radionuclide distribution (40K, 214Bi from the 238U decay series, and 208Tl from the 232Th decay series) were produced after the conclusion of measurements each day. Natural radionuclide specific activities (Bq kg-1 ) were estimated using a spectral windows method with stripping1 , using a working calibration assuming planar geometry and uniform activity distribution. As agreed prior to the start of work, a working calibration derived from field measurements and photon fluence calculations conducted for similar detectors in the 1990s2 has been used here, with calibration parameters given in the appendix. This report presents the dose rate maps produced during the field work, with a very brief description of the data. Summary statistics for each data set are presented in Table 1. All data have been mapped using a UTM (zone 29T) grid, with the approximate location of ground features added by hand as a guide. Further work could be conducted to produce more accurate overlays of ground features. At each site in-situ gamma spectrometry measurements were also conducted by ITN, and the data collected by the two detector systems and the soil samples will be compared at a later date
    • 

    corecore