10 research outputs found

    BASS. XXV. DR2 broad-line-based black hole mass estimates and biases from obscuration

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    We present measurements of broad emission lines and virial estimates of supermassive black hole masses (MBHM_{BH}) for a large sample of ultra-hard X-ray selected active galactic nuclei (AGNs) as part of the second data release of the BAT AGN Spectroscopic Survey (BASS/DR2). Our catalog includes MBHM_{BH} estimates for a total 689 AGNs, determined from the Hα\alpha, Hβ\beta, MgIIλ2798MgII\lambda2798, and/or CIVλ1549CIV\lambda1549 broad emission lines. The core sample includes a total of 512 AGNs drawn from the 70-month Swift/BAT all-sky catalog. We also provide measurements for 177 additional AGNs that are drawn from deeper Swift/BAT survey data. We study the links between MBHM_{BH} estimates and line-of-sight obscuration measured from X-ray spectral analysis. We find that broad Hα\alpha emission lines in obscured AGNs (log(NH/cm2)>22.0\log (N_{\rm H}/{\rm cm}^{-2})> 22.0) are on average a factor of 8.02.4+4.18.0_{-2.4}^{+4.1} weaker, relative to ultra-hard X-ray emission, and about 3512 +735_{-12}^{~+7}\% narrower than in unobscured sources (i.e., log(NH/cm2)<21.5\log (N_{\rm H}/{\rm cm}^{-2}) < 21.5). This indicates that the innermost part of the broad-line region is preferentially absorbed. Consequently, current single-epoch MBHM_{BH} prescriptions result in severely underestimated (>>1 dex) masses for Type 1.9 sources (AGNs with broad Hα\alpha but no broad Hβ\beta) and/or sources with log(NH/cm2)>22.0\log (N_{\rm H}/{\rm cm}^{-2}) > 22.0. We provide simple multiplicative corrections for the observed luminosity and width of the broad Hα\alpha component (L[bHα]L[{\rm b}{\rm H}\alpha] and FWHM[bHα\alpha]) in such sources to account for this effect, and to (partially) remedy MBHM_{BH} estimates for Type 1.9 objects. As key ingredient of BASS/DR2, our work provides the community with the data needed to further study powerful AGNs in the low-redshift Universe.Comment: published in ApJ

    Consenso colombiano de atención, diagnóstico y manejo de la infección por SARS-COV-2/COVID-19 en establecimientos de atención de la salud Recomendaciones basadas en consenso de expertos e informadas en la evidencia

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    The “Asociación Colombiana de Infectología” (ACIN) and the “Instituto de Evaluación de Nuevas Tecnologías de la Salud” (IETS) created a task force to develop recommendations for Covid 19 health care diagnosis, management and treatment informed, and based, on evidence. Theses reccomendations are addressed to the health personnel on the Colombian context of health services. © 2020 Asociacion Colombiana de Infectologia. All rights reserved
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