7,626 research outputs found

    The extraordinary mid-infrared spectral properties of FeLoBAL Quasars

    Get PDF
    We present mid-infrared spectra of six FeLoBAL QSOs at 1<z<1.8, taken with the Spitzer space telescope. The spectra span a range of shapes, from hot dust dominated AGN with silicate emission at 9.7 microns, to moderately obscured starbursts with strong Polycyclic Aromatic Hydrocarbon (PAH) emission. The spectrum of one object, SDSS 1214-0001, shows the most prominent PAHs yet seen in any QSO at any redshift, implying that the starburst dominates the mid-IR emission with an associated star formation rate of order 2700 solar masses per year. With the caveats that our sample is small and not robustly selected, we combine our mid-IR spectral diagnostics with previous observations to propose that FeLoBAL QSOs are at least largely comprised of systems in which (a) a merger driven starburst is ending, (b) a luminous AGN is in the last stages of burning through its surrounding dust, and (c) which we may be viewing over a restricted line of sight range.Comment: ApJ, accepte

    Rights of passage: law and the biopolitics of dying

    Get PDF
    Deleuze and Law: Forensic Futures explores the relation between law and life and the advent of a politics of 'life'. How have recent events focused social, political and cultural attention on the living body and its maintenance and management? The central concept, through which the embodiment of the subject will be examined will be that of 'bio-power'. Articulated by Michel Foucault, but brought to attention more recently in the work of Giorgio Agamben, this concept recognises that the relation between life and law is both historical and necessary: the law must operate on bodies but can only do so by establishing a border between the body of the polity, and the mere life excepted from political concern. The contemporary advent of bio-politics occurs when the polity increasingly and invasively operates on this 'mere' life, and the body or organism – rather than the self – becomes the object of political management. The manner in which the body becomes the focus of contemporary power has led legal theory to explore new questions of the threshold between life and death and has led social theory to question the new extensions of the law and the polity into embodied life. The contributors explore the forensic shift in contemporary social theory and cultural sensibility from a number of perspectives. Description of book from publisher website at: http://www.palgrave.com

    The Statistical Approach to Quantifying Galaxy Evolution

    Get PDF
    Studies of the distribution and evolution of galaxies are of fundamental importance to modern cosmology; these studies, however, are hampered by the complexity of the competing effects of spectral and density evolution. Constructing a spectroscopic sample that is able to unambiguously disentangle these processes is currently excessively prohibitive due to the observational requirements. This paper extends and applies an alternative approach that relies on statistical estimates for both distance (z) and spectral type to a deep multi-band dataset that was obtained for this exact purpose. These statistical estimates are extracted directly from the photometric data by capitalizing on the inherent relationships between flux, redshift, and spectral type. These relationships are encapsulated in the empirical photometric redshift relation which we extend to z ~ 1.2, with an intrinsic dispersion of dz = 0.06. We also develop realistic estimates for the photometric redshift error for individual objects, and introduce the utilization of the galaxy ensemble as a tool for quantifying both a cosmological parameter and its measured error. We present deep, multi-band, optical number counts as a demonstration of the integrity of our sample. Using the photometric redshift and the corresponding redshift error, we can divide our data into different redshift intervals and spectral types. As an example application, we present the number redshift distribution as a function of spectral type.Comment: 40 pages (LaTex), 21 Figures, requires aasms4.sty; Accepted by the Astrophysical Journa

    Accurate molecular energies by extrapolation of atomic energies using an analytic quantum mechanical model

    Full text link
    Using a new analytic quantum mechanical method based on Slater's Xalpha method, we show that a fairly accurate estimate of the total energy of a molecule can be obtained from the exact energies of its constituent atoms. The mean absolute error in the total energies thus determined for the G2 set of 56 molecules is about 16 kcal/mol, comparable to or better than some popular pure and hybrid density functional models.Comment: 5 pages, REVTE
    • 

    corecore