The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Katja Pottschmidt - One of the best experts on this subject based on the ideXlab platform.
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the Causal Connection between disc and power law variability in hard state black hole x ray binaries
Monthly Notices of the Royal Astronomical Society: Letters, 2011Co-Authors: P Uttley, T J Wilkinson, P Cassatella, J Wilms, Katja Pottschmidt, Manfred Hanke, M BockAbstract:We use the XMM–Newton EPIC-pn instrument in timing mode to extend spectral time-lag studies of hard state black hole X-ray binaries into the soft X-ray band. We show that variations of the disc blackbody emission substantially lead variations in the power-law emission, by tenths of a second on variability time-scales of seconds or longer. The large lags cannot be explained by Compton scattering but are consistent with time delays due to viscous propagation of mass accretion fluctuations in the disc. However, on time-scales less than a second the disc lags the power-law variations by a few milliseconds, consistent with the disc variations being dominated by X-ray heating by the power law, with the short lag corresponding to the light traveltime between the power-law emitting region and the disc. Our results indicate that instabilities in the accretion disc are responsible for continuum variability on time-scales of seconds or longer and probably also on shorter time-scales.
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the Causal Connection between disc and power law variability in hard state black hole x ray binaries
arXiv: High Energy Astrophysical Phenomena, 2011Co-Authors: P Uttley, T J Wilkinson, P Cassatella, J Wilms, Katja Pottschmidt, Manfred Hanke, M BoeckAbstract:We use the XMM-Newton EPIC-pn instrument in timing mode to extend spectral time-lag studies of hard state black hole X-ray binaries into the soft X-ray band. We show that variations of the disc blackbody emission substantially lead variations in the power-law emission, by tenths of a second on variability time-scales of seconds or longer. The large lags cannot be explained by Compton scattering but are consistent with time-delays due to viscous propagation of mass accretion fluctuations in the disc. However, on time-scales less than a second the disc lags the power-law variations by a few ms, consistent with the disc variations being dominated by X-ray heating by the power-law, with the short lag corresponding to the light-travel time between the power-law emitting region and the disc. Our results indicate that instabilities in the accretion disc are responsible for continuum variability on time-scales of seconds or longer and probably also on shorter time-scales.
M Bock - One of the best experts on this subject based on the ideXlab platform.
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the Causal Connection between disc and power law variability in hard state black hole x ray binaries
Monthly Notices of the Royal Astronomical Society: Letters, 2011Co-Authors: P Uttley, T J Wilkinson, P Cassatella, J Wilms, Katja Pottschmidt, Manfred Hanke, M BockAbstract:We use the XMM–Newton EPIC-pn instrument in timing mode to extend spectral time-lag studies of hard state black hole X-ray binaries into the soft X-ray band. We show that variations of the disc blackbody emission substantially lead variations in the power-law emission, by tenths of a second on variability time-scales of seconds or longer. The large lags cannot be explained by Compton scattering but are consistent with time delays due to viscous propagation of mass accretion fluctuations in the disc. However, on time-scales less than a second the disc lags the power-law variations by a few milliseconds, consistent with the disc variations being dominated by X-ray heating by the power law, with the short lag corresponding to the light traveltime between the power-law emitting region and the disc. Our results indicate that instabilities in the accretion disc are responsible for continuum variability on time-scales of seconds or longer and probably also on shorter time-scales.
P Uttley - One of the best experts on this subject based on the ideXlab platform.
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the Causal Connection between disc and power law variability in hard state black hole x ray binaries
Monthly Notices of the Royal Astronomical Society: Letters, 2011Co-Authors: P Uttley, T J Wilkinson, P Cassatella, J Wilms, Katja Pottschmidt, Manfred Hanke, M BockAbstract:We use the XMM–Newton EPIC-pn instrument in timing mode to extend spectral time-lag studies of hard state black hole X-ray binaries into the soft X-ray band. We show that variations of the disc blackbody emission substantially lead variations in the power-law emission, by tenths of a second on variability time-scales of seconds or longer. The large lags cannot be explained by Compton scattering but are consistent with time delays due to viscous propagation of mass accretion fluctuations in the disc. However, on time-scales less than a second the disc lags the power-law variations by a few milliseconds, consistent with the disc variations being dominated by X-ray heating by the power law, with the short lag corresponding to the light traveltime between the power-law emitting region and the disc. Our results indicate that instabilities in the accretion disc are responsible for continuum variability on time-scales of seconds or longer and probably also on shorter time-scales.
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the Causal Connection between disc and power law variability in hard state black hole x ray binaries
arXiv: High Energy Astrophysical Phenomena, 2011Co-Authors: P Uttley, T J Wilkinson, P Cassatella, J Wilms, Katja Pottschmidt, Manfred Hanke, M BoeckAbstract:We use the XMM-Newton EPIC-pn instrument in timing mode to extend spectral time-lag studies of hard state black hole X-ray binaries into the soft X-ray band. We show that variations of the disc blackbody emission substantially lead variations in the power-law emission, by tenths of a second on variability time-scales of seconds or longer. The large lags cannot be explained by Compton scattering but are consistent with time-delays due to viscous propagation of mass accretion fluctuations in the disc. However, on time-scales less than a second the disc lags the power-law variations by a few ms, consistent with the disc variations being dominated by X-ray heating by the power-law, with the short lag corresponding to the light-travel time between the power-law emitting region and the disc. Our results indicate that instabilities in the accretion disc are responsible for continuum variability on time-scales of seconds or longer and probably also on shorter time-scales.
Joshua Shemer - One of the best experts on this subject based on the ideXlab platform.
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deaths following influenza vaccination background mortality or Causal Connection
Vaccine, 2007Co-Authors: Ehud Kokia, Barbara Silverman, Manfred S Green, Hagai Kedem, Michal Guindy, Joshua ShemerAbstract:Abstract In October 2006, four deaths occurred in Israel shortly after influenza immunization, resulting in a temporary halt to the vaccination campaign. After an epidemiologic investigation, the Ministry of Health concluded that these deaths were not related to the vaccine itself and the campaign resumed; however, vaccine uptake was markedly reduced. Estimates of true background mortality in this high-risk population would aid in public education and quell unnecessary concerns regarding vaccine safety. We used data from a large HMO to estimate mortality in influenza vaccine recipients aged 55 and over during four consecutive winters (2003, 2004, 2005 and 2006). Date of immunization was ascertained from patient treatment files, vital status through Israeli National Insurance Institute data. We calculated crude death rates within 7, 14 and 30 days of influenza immunization, and used a Cox Proportional Hazards Model to estimate the risk of death within 14 days of vaccination, adjusting for age and comorbid conditions (age over 75, history of diabetes or cardiovascular disease, status as homebound patient) in 2006. The death rate among influenza vaccine recipients ranged from 0.01 to 0.02% within 7 days and 0.09–0.10% at 30 days. Influenza immunization was associated with a decreased risk of death within 14 days after adjustment for comorbidities (Hazard ratio, 0.33, 95% CI, 0.18–0.61). Our findings support the assumption that influenza vaccination is not associated with increased risk of death in the short term.
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Deaths following influenza vaccination—background mortality or Causal Connection?
Vaccine, 2007Co-Authors: Ehud Kokia, Manfred S Green, Hagai Kedem, Michal Guindy, Barbara G. Silverman, Joshua ShemerAbstract:Abstract In October 2006, four deaths occurred in Israel shortly after influenza immunization, resulting in a temporary halt to the vaccination campaign. After an epidemiologic investigation, the Ministry of Health concluded that these deaths were not related to the vaccine itself and the campaign resumed; however, vaccine uptake was markedly reduced. Estimates of true background mortality in this high-risk population would aid in public education and quell unnecessary concerns regarding vaccine safety. We used data from a large HMO to estimate mortality in influenza vaccine recipients aged 55 and over during four consecutive winters (2003, 2004, 2005 and 2006). Date of immunization was ascertained from patient treatment files, vital status through Israeli National Insurance Institute data. We calculated crude death rates within 7, 14 and 30 days of influenza immunization, and used a Cox Proportional Hazards Model to estimate the risk of death within 14 days of vaccination, adjusting for age and comorbid conditions (age over 75, history of diabetes or cardiovascular disease, status as homebound patient) in 2006. The death rate among influenza vaccine recipients ranged from 0.01 to 0.02% within 7 days and 0.09–0.10% at 30 days. Influenza immunization was associated with a decreased risk of death within 14 days after adjustment for comorbidities (Hazard ratio, 0.33, 95% CI, 0.18–0.61). Our findings support the assumption that influenza vaccination is not associated with increased risk of death in the short term.
J Wilms - One of the best experts on this subject based on the ideXlab platform.
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the Causal Connection between disc and power law variability in hard state black hole x ray binaries
Monthly Notices of the Royal Astronomical Society: Letters, 2011Co-Authors: P Uttley, T J Wilkinson, P Cassatella, J Wilms, Katja Pottschmidt, Manfred Hanke, M BockAbstract:We use the XMM–Newton EPIC-pn instrument in timing mode to extend spectral time-lag studies of hard state black hole X-ray binaries into the soft X-ray band. We show that variations of the disc blackbody emission substantially lead variations in the power-law emission, by tenths of a second on variability time-scales of seconds or longer. The large lags cannot be explained by Compton scattering but are consistent with time delays due to viscous propagation of mass accretion fluctuations in the disc. However, on time-scales less than a second the disc lags the power-law variations by a few milliseconds, consistent with the disc variations being dominated by X-ray heating by the power law, with the short lag corresponding to the light traveltime between the power-law emitting region and the disc. Our results indicate that instabilities in the accretion disc are responsible for continuum variability on time-scales of seconds or longer and probably also on shorter time-scales.
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the Causal Connection between disc and power law variability in hard state black hole x ray binaries
arXiv: High Energy Astrophysical Phenomena, 2011Co-Authors: P Uttley, T J Wilkinson, P Cassatella, J Wilms, Katja Pottschmidt, Manfred Hanke, M BoeckAbstract:We use the XMM-Newton EPIC-pn instrument in timing mode to extend spectral time-lag studies of hard state black hole X-ray binaries into the soft X-ray band. We show that variations of the disc blackbody emission substantially lead variations in the power-law emission, by tenths of a second on variability time-scales of seconds or longer. The large lags cannot be explained by Compton scattering but are consistent with time-delays due to viscous propagation of mass accretion fluctuations in the disc. However, on time-scales less than a second the disc lags the power-law variations by a few ms, consistent with the disc variations being dominated by X-ray heating by the power-law, with the short lag corresponding to the light-travel time between the power-law emitting region and the disc. Our results indicate that instabilities in the accretion disc are responsible for continuum variability on time-scales of seconds or longer and probably also on shorter time-scales.
