1,619 research outputs found

    Temperature Variation of Debye-Waller Factor and Mean Square Displacement for some Transition Metals

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    A General Precipitation-Limited L_X-T-R Relation Among Early-Type Galaxies

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    The relation between X-ray luminosity (L_X) and ambient gas temperature (T) among massive galactic systems is an important cornerstone of both observational cosmology and galaxy-evolution modeling. In the most massive galaxy clusters, the relation is determined primarily by cosmological structure formation. In less massive systems, it primarily reflects the feedback response to radiative cooling of circumgalactic gas. Here we present a simple but powerful model for the L_X-T relation as a function of physical aperture R within which those measurements are made. The model is based on the precipitation framework for AGN feedback and assumes that the circumgalactic medium is precipitation-regulated at small radii and limited by cosmological structure formation at large radii. We compare this model with many different data sets and show that it successfully reproduces the slope and upper envelope of the L_X-T-R relation over the temperature range from ~0.2 keV through >10 keV. Our findings strongly suggest that the feedback mechanisms responsible for regulating star formation in individual massive galaxies have much in common with the precipitation-triggered feedback that appears to regulate galaxy-cluster cores.Comment: Submitted to ApJ, 9 pages, 3 figures (v2 fixes a few small typos

    Računanje vrpčaste strukture nelokalnim pseudopotencijalima

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    Energy bands of Rb and Cs have been calculated for the first time using average or effective pseudopotentials obtained from non-local ones. It is shown that the results so obtained compare well to those obtained with full non-local calculations.Načinili smo prve račune energijskih vrpci Rb i Cs primjenom prosječnog ili efektivnog pseudopotencijala koji smo izveli iz nelokalnih pseudopotencijala. Pokazuje se dobra suglasnost ishoda tih računa i računa primjenom potpunih nelokalnih pseudopotencijala

    Diferencijalni udarni presjeci za rašprsenje elektrona atomima iterbija

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    Electron scattering by ytterbium atom is studied at energies 10, 20, 40, 60 and 80 eV, by applying a parameter-free complex optical potential. The real part of the complex optical potential includes the static potential Vst(r), the polarization potential Vpol(r) that consists of the short range correlation and long-range polarization effects and Vex(r) term consisting of electron exchange interaction which is modelled by assuming the electron charge cloud as a free electron gas. The loss of flux into the inelastic channels is included via a phenomenological absorption potential. Our results are compared with the recent experimental measurements.Proučavamo raspršenje elektrona na enegijama 10, 20, 40, 60 i 80 eV primjenom bezparametarskog kompleksnog optičkog potencijala. Realni dio optičkog potencijala uključuje statički potencijal Vst(r), polarizacijski potencijal Vpol(r) koji se sastoji od kratko-dosežnih korelacija i dugo-dosežnih polarizacijskih efekata i član Vex(r) koji se sastoji od elektronskog međudjelovanja izmjene, a izražen je pretpostavivši oblak elektronskog naboja kao slobodan elektronski plin. Gubitak toka u neelastične kanale uključuje se preko fenomenološkog apsorpcijskog potencijala. Postignuti ishodi uspoređuju se s nedavnim eksperimentalnim podacima

    Računanje vrpčaste strukture nelokalnim pseudopotencijalima

    Get PDF
    Energy bands of Rb and Cs have been calculated for the first time using average or effective pseudopotentials obtained from non-local ones. It is shown that the results so obtained compare well to those obtained with full non-local calculations.Načinili smo prve račune energijskih vrpci Rb i Cs primjenom prosječnog ili efektivnog pseudopotencijala koji smo izveli iz nelokalnih pseudopotencijala. Pokazuje se dobra suglasnost ishoda tih računa i računa primjenom potpunih nelokalnih pseudopotencijala

    Ukupni (elastični i neelastični) udarni presjeci raspršenja elektrona na molekulama N2O, CF4, NO I F2

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    Electron impact total (elastic + inelastic) cross sections and total ionization cross sections are calculated for N2O, CF4, NO and F2 molecules from the thresholds to 5 keV. A model complex optical potential is calculated for each collision system from the corresponding molecular wave function at the Hartree-Fock level. The resulting complex optical potential, free from any adjustable parameter, is treated exactly in a variable-phase approach to calculate scattering complex phase shifts and the total cross sections. The present results are found to be consistent with the existing experimental measurements.Izračunali smo ukupne elektronske sudarne (elastične i neelastične) i ukupne ionizacijske udarne presjeke za molekule N2O, CF4, NO i F2 za energije od praga do 5 keV. Modelske kompleksne optičke potencijale smo izračunali za svaki sustav na osnovi odgovarajućih molekulskih Hartree-Fockovih valnih funkcija. Postignute optičke potencijale, bez parametara za podešavanje, primijenili smo egzaktno s promjenljivim fazama u računima kompleksnih faznih pomaka i ukupnih udarnih presjeka. Ishodi računa su u skladu s dostupnim rezultatima mjerenja

    Diferencijalni udarni presjeci za rašprsenje elektrona atomima iterbija

    Get PDF
    Electron scattering by ytterbium atom is studied at energies 10, 20, 40, 60 and 80 eV, by applying a parameter-free complex optical potential. The real part of the complex optical potential includes the static potential Vst(r), the polarization potential Vpol(r) that consists of the short range correlation and long-range polarization effects and Vex(r) term consisting of electron exchange interaction which is modelled by assuming the electron charge cloud as a free electron gas. The loss of flux into the inelastic channels is included via a phenomenological absorption potential. Our results are compared with the recent experimental measurements.Proučavamo raspršenje elektrona na enegijama 10, 20, 40, 60 i 80 eV primjenom bezparametarskog kompleksnog optičkog potencijala. Realni dio optičkog potencijala uključuje statički potencijal Vst(r), polarizacijski potencijal Vpol(r) koji se sastoji od kratko-dosežnih korelacija i dugo-dosežnih polarizacijskih efekata i član Vex(r) koji se sastoji od elektronskog međudjelovanja izmjene, a izražen je pretpostavivši oblak elektronskog naboja kao slobodan elektronski plin. Gubitak toka u neelastične kanale uključuje se preko fenomenološkog apsorpcijskog potencijala. Postignuti ishodi uspoređuju se s nedavnim eksperimentalnim podacima

    Ukupni (elastični i neelastični) udarni presjeci raspršenja elektrona na molekulama N2O, CF4, NO I F2

    Get PDF
    Electron impact total (elastic + inelastic) cross sections and total ionization cross sections are calculated for N2O, CF4, NO and F2 molecules from the thresholds to 5 keV. A model complex optical potential is calculated for each collision system from the corresponding molecular wave function at the Hartree-Fock level. The resulting complex optical potential, free from any adjustable parameter, is treated exactly in a variable-phase approach to calculate scattering complex phase shifts and the total cross sections. The present results are found to be consistent with the existing experimental measurements.Izračunali smo ukupne elektronske sudarne (elastične i neelastične) i ukupne ionizacijske udarne presjeke za molekule N2O, CF4, NO i F2 za energije od praga do 5 keV. Modelske kompleksne optičke potencijale smo izračunali za svaki sustav na osnovi odgovarajućih molekulskih Hartree-Fockovih valnih funkcija. Postignute optičke potencijale, bez parametara za podešavanje, primijenili smo egzaktno s promjenljivim fazama u računima kompleksnih faznih pomaka i ukupnih udarnih presjeka. Ishodi računa su u skladu s dostupnim rezultatima mjerenja

    Spatially resolved kinematics in the central 1 kpc of a compact star-forming galaxy at z=2.3 from ALMA CO observations

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    We present high spatial resolution (FWHM\sim0.14'') observations of the CO(878-7) line in GDS-14876, a compact star-forming galaxy at z=2.3z=2.3 with total stellar mass of log(M/M)=10.9\log(M_{\star}/M_{\odot})=10.9. The spatially resolved velocity map of the inner r1r\lesssim1~kpc reveals a continous velocity gradient consistent with the kinematics of a rotating disk with vrot(r=1kpc)=163±5v_{\rm rot}(r=1\rm kpc)=163\pm5 km s1^{-1} and vrot/σ2.5v_{\rm rot}/\sigma\sim2.5. The gas-to-stellar ratios estimated from CO(878-7) and the dust continuum emission span a broad range, fgasCO=Mgas/M=1345%f^{\rm CO}_{\rm gas}=M_{\rm gas}/M_{\star}=13-45\% and fgascont=5067%f^{\rm cont}_{\rm gas}=50-67\%, but are nonetheless consistent given the uncertainties in the conversion factors. The dynamical modeling yields a dynamical mass oflog(Mdyn/M)=10.580.2+0.5\log(M_{\rm dyn}/M_{\odot})=10.58^{+0.5}_{-0.2} which is lower, but still consistent with the baryonic mass, log\log(Mbar_{\rm bar}= M_{\star} + MgasCO^{\rm CO}_{\rm gas}/M_{\odot})=11.0=11.0, if the smallest CO-based gas fraction is assumed. Despite a low, overall gas fraction, the small physical extent of the dense, star-forming gas probed by CO(878-7), 3×\sim3\times smaller than the stellar size, implies a strong concentration that increases the gas fraction up to fgasCO,1kpc85%f^{\rm CO, 1\rm kpc}_{\rm gas}\sim 85\% in the central 1 kpc. Such a gas-rich center, coupled with a high star-formation rate, SFR\sim 500 M_{\odot} yr1^{-1}, suggests that GDS-14876 is quickly assembling a dense stellar component (bulge) in a strong nuclear starburst. Assuming its gas reservoir is depleted without replenishment, GDS-14876 will quickly (tdepl27t_{\rm depl}\sim27 Myr) become a compact quiescent galaxy that could retain some fraction of the observed rotational support.Comment: Accepted for Publication in ApJL. Kinematic maps are shown in Figures 2 and
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