962 research outputs found

    Constraints on hot metals in the Vicinity of the Galaxy

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    We have searched for evidence of soft X-ray absorption by hot metals in the vicinity of the Galaxy in the spectra of a small sample of fifteen Type I AGN observed with the high resolution X-ray gratings on board Chandra. This is an extension of our previous survey of hot OVII and OVIII absorbing gas in the vicinity of the Galaxy. The strongest absorption signatures within a few hundred km/s of their rest-frame energies are most likely due to warm absorbing outflows from the nearest AGN, which are back-lighting the local hot gas. We emphasize that absorption signatures in the spectra of some distant AGN that are kinematically consistent with the recessional velocity of the AGN are most likely to be due to hot local gas. Along the sightline towards PG 1211+143, PDS 456 and MCG-6-30-15 there is a very large absorbing Fe column density which is kinematically consistent with absorption by hot, local Fe. The sightlines to these three AGN pass through the limb of the Northern Polar Spur (NPS), a local bubble formed from several supernovae which, if rich in Fe, may account for a large local Fe column. We obtain limits on the column density of local, highly ionized N, Ne, Mg, Si along all of the sightlines in our sample. We correlate the column density limits with those of highly ionized O along the same sightlines. Assuming the hot local gas is in collisionally ionized equilibrium, we obtain limits on the temperature and relative abundances of the metals in the hot local gas. Our limits on the ionic column densities in the local hot gas seem to be consistent with those observed in the hot halo gas of edge-on normal spiral galaxies.Comment: 9 pages,2 figures, MNRAS (accepted

    NGC 4388: A Test Case for Relativistic Disk Reflection and Fe K Fluorescence Features

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    We present a new analysis of the Suzaku X-ray spectrum of the Compton-thin Seyfert 2 galaxy NGC 4388. The spectrum above ∼\sim2 keV can be described by a remarkably simple and rather mundane model, consisting of a uniform, neutral spherical distribution of matter, with a radial column density of 2.58±0.02×10232.58 \pm 0.02 \times 10^{23} cm−2^{-2}, and an Fe abundance of 1.102−0.021+0.0241.102^{+0.024}_{-0.021} relative to solar. The model does not require any phenomenological adjustments to self-consistently account for the low-energy extinction, the Fe Kα\alpha and Fe Kβ\beta fluorescent emission lines, the Fe K edge, and the Compton-scattered continuum from the obscuring material. The spherical geometry is not a unique description, however, and the self-consistent, solar abundance MYTORUS model, applied with toroidal and non-toroidal geometries, gives equally good descriptions of the data. In all cases, the key features of the spectrum are so tightly locked together that for a wide range of parameters, a relativistic disk-reflection component contributes no more than ∼\sim2% to the net spectrum in the 2-20 keV band. We show that the commonly invoked explanations for weak X-ray reflection features, namely a truncated and/or very highly ionized disk, do not work for NGC 4388. If relativistically-broadened Fe Kα\alpha lines and reflection are ubiquitous in Seyfert 1 galaxies, they should also be ubiquitous in Compton-thin Seyfert 2 galaxies. The case of NGC 4388 shows the need for similar studies of more Compton-thin AGN to ascertain whether this is true.Comment: MNRAS accepted. 21 pages, 7 figures, 4 tables; Appendix with historical notes and 1 table. This version: Corrected minor typo and affiliatio

    The Ubiquity and Magnitude of Large FeKα\alpha Equivalent Widths in AGN Extended Regions

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    Narrow Fe Kα\alpha fluorescent emission lines arising at ∼\simkpc-scale separations from the nucleus have only been detected in a few AGN. The detections require that the extended line emission be spatially resolved and sufficiently bright. Compared to narrow Fe Kα\alpha lines arising closer to the nucleus, they have much lower fluxes but show substantially larger equivalent widths, EWFeKα_{\rm Fe K\alpha}. We show that, in the optically-thin limit, a purely analytical argument naturally predicts large, EWFeKα∼_{\rm FeK\alpha}\sim1 keV, values for such lines, regardless of the details of equivalent hydrogen column density, NHN_H, or reprocessor geometry. Monte Carlo simulations corroborate this result and show that the simple analytic EWFeKα_{\rm FeK\alpha} prescription holds up to higher NHN_H approaching the Compton-thick regime. We compare to ChandraChandra observations from the literature and discuss that our results are consistent with the large EWFeKα_{\rm FeK\alpha} values reported for local AGN, for which the line is detected in extended, up to ∼\simkpc-scale, regions. We argue that large EWFeKα_{\rm FeK\alpha} from kpc-scale regions in AGN should be ubiquitous, because they do not depend on the absolute luminosity of the central X-ray source, and are measured only against the scattered continuum. We predict values to be of the order of ∼\sim1 keV or larger, even for covering factors ≪\ll1, and for arbitrarily small column densities. We propose that the large-scale molecular material that is now routinely being detected with the Atacama Large Millimeter/Submillimeter Array (ALMA) may act as an extended X-ray scattering reprocessor giving rise to ∼\simkpc-scale Fe Kα\alpha emission.Comment: Accepted for publication in Physical Review D. 9 pages, 6 figure

    A Highly Doppler Blueshifted Fe-K Emission Line in the High-Redshift QSO PKS 2149-306

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    We report the results from an \asca observation of the QSO PKS 2149-306 (z=2.345). We detect an emission line centered at ∼17\sim 17 keV in the quasar frame. Line emission at this energy has not been observed in any other active galaxy or quasar to date. We present evidence rejecting the possibility that this line is the result of instrumental artifacts, or a serendipitous source. The most likely explanation is blueshifted Fe-K emission (the EW is 300+/-200 eV, QSO frame). Bulk velocities of the order of 0.75c are implied by the data. We show that Fe-K line photons originating in an accretion disk and Compton-scattering off a leptonic can account for the emission line. Curiously, if the emission-line feature recently discovered in another quasar PKS 0637−-752, z=0.654z=0.654, is blueshifted Ovii, the Doppler factor is the same (~2.7) for both.Comment: 15 pages plus 3 figures. Latex with separate .ps files (Accepted by Astrophysical Journal Letters

    Effects of Economic and Population Factors on Health Expenditures: Special Case of Pakistan

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    This paper aims to explore the factors affecting the health care expenditures of Pakistan by employing the Multivariate techniques for the annual data series from 1960 to 2010 .The variables we considered are Gross Domestic Product (GDP) as an economic indicator, Population of age 65 and above (P≥65), Population of age 0 to 14 (P(0-14)), Life expectancy at Birth (LE), Crude Birth rate (CBR) and population growth rate (GR) as population indicator and Total Health Expenditure (THE) as an influencing factor. Multiple regression considering Total Health Expenditure (THE) is applied as dependent on the variables mentioned above. Since Variance Inflation Factor (VIF) for all independent variables are very high, the smallest VIF is around 11 goes up to 65. The results obtained by Principal components reveal the effect of population structure and the age factor effect oppositely on Total Health Expenditures (THE). Factor Analysis suggests that the behavior of Health Expenditures is common with Gross Domestic Product (GDP), population of age 65 and above (P≥65) and life expectancy at Birth (LE) in Pakistan while population of age 0 to 14 (P (0-14)), population growth rate (GR) and Crude Birth rate (CBR) are moving in opposite direction i.e. as GDP, P≥65 and LE of Pakistan increases P (0-14), GR and CBR will decreases

    Mammary echinococcosis: Two cases and literature review

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    Inflammatory myofibroblastic tumor of the lung in an adolescent boy

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    Inflammatory myofibroblastic tumors of the lung are rare, here, an unusual case is described. A 14-year-old boy presented with a history of weight loss and clubbing and was found to have a solitary circumscribed mass in right lower lobe treated with lobectomy. This case indicates the need for early and complete removal of the inflammatory myofibroblastic tumor of the lung

    MOLECULAR CHARACTERIZATION BY USING RANDOM AMPLIFIED POLYMORPHIC DNA (RAPD) ANALYSIS OF SALMONELLA ENTERITIDIS ISOLATES RECOVERED FROM AVIAN AND HUMAN SOURCES

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    Random amplified polymorphic DNA (RAPD) analysis was applied for molecular characterization of five Salmonella enteritidis strains from different avian sources and human cases of infection. A total of 16 primers were used and only five primers showed good discriminatory power for all five isolates. Dendrogram showed a common lineage among all five isolates. There was a close genetic relationship among isolates of eggs and human sources, while there was less pronounced homology among isolates of broiler meat and human sources. On the basis of results we have found that an endemic strain of S. enteritidis is prevalent between the poultry derived food and humans which gives us an insight to genetic diversity of S. enteritidis from these sources

    Probing the unified model in NGC 7314

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    We present a study of the complex absorbed X-ray spectrum of the Narrow Line Seyfert 1 galaxy NGC 7314. We collected available public X-ray data from the archives of XMM-Newton, Suzaku, and ASCA. The spectra were analyzed using the fitting package SPEX. We find evidence of intrinsic neutral and ionized absorption in the XMM-Newton EPIC-pn spectrum. The ionized gas presents three significantly distinct ionization phases, although its kinematic properties could not be disentangled. At least two of these phases are also detected in the RGS spectrum, although with less significance due to the low statistics. The ASCA and Suzaku spectra show larger neutral absorption but no ionized gas signatures. The Fe Kalpha emission line is detected in all the observations and, additionally, Fe XXVI in the EPIC-pn spectrum, and Fe Kbeta in the Suzaku XIS spectrum. Using this observational evidence we construct a consistent picture of the geometry of the system in the context of the unified model of active galactic nuclei. The different observational properties are thus interpreted as clouds of neutral gas moving across our line of sight, which would be grazing a clumpy dusty torus.Comment: 9 pages, 8 figures. Accepted for publication in Astronomy and Astrophysic

    Simultaneous X-ray and UV spectroscopy of the Seyfert 1 galaxy NGC 5548.II. Physical conditions in the X-ray absorber

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    We present the results from a 500 ks Chandra observation of the Seyfert 1 galaxy NGC 5548. We detect broadened emission lines of O VII and C VI in the spectra, similar to those observed in the optical and UV bands. The source was continuously variable, with a 30 % increase in luminosity in the second half of the observation. No variability in the warm absorber was detected between the spectra from the first 170 ks and the second part of the observation. The velocity structure of the X-ray absorber is consistent with the velocity structure measured simultaneously in the ultraviolet spectra. We find that the highest velocity outflow component, at -1040 km/s, becomes increasingly important for higher ionization parameters. This velocity component spans at least three orders of magnitude in ionization parameter, producing both highly ionized X-ray absorption lines (Mg XII, Si XIV) as well as UV absorption lines. A similar conclusion is very probable for the other four velocity components. Based upon our observations, we argue that the warm absorber probably does not manifest itself in the form of photoionized clumps in pressure equilibrium with a surrounding wind. Instead, a model with a continuous distribution of column density versus ionization parameter gives an excellent fit to our data. From the shape of this distribution and the assumption that the mass loss through the wind should be smaller than the accretion rate onto the black hole, we derive upper limits to the solid angle as small as 10^{-4} sr. From this we argue that the outflow occurs in density-stratified streamers. The density stratification across the stream then produces the wide range of ionization parameter observed in this source. Abridged.Comment: 21 pages, 12 figures accepted for publication in A&
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