| 报告题目： |
Quasars and the dark energy |
| 报告人： |
Bozena Czerny |
| 报告人单位： |
Center for Theoretical Physics, Warsaw, Poland |
| 报告时间： |
4月22号上午10:30 |
| 报告地点： |
科技北楼410 |
| 报告摘要： |
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Dark energy can be studied with a number of probes, broadly classified as standard candles and standard rulers. The use of several independent probes is needed to get accurate and reliable results since every probe has its particular systematic problems/biases. Quasars do not seem to be obvious standard candles but there are two ways to pursue. The first method is based on the selection of special sub-class of quasars, which radiate precisely at Eddington ratio. The second method can use all quasars, but requires to perform the monitoring of the quasar variability of the continuum and of the emission lines. Reverberation studies (i.e. the measurements of the time delay of the line emission with respect to the continuum) allow to establish the absolute monochromatic luminosity of a given source independently of its redshift. We developed a theory which explains the delay-luminosity relation known for nearby sources and allows to extrapolate this type of relation towards higher black hole mass sources, like quasars at redshifts of a few. Preliminary studies are being done using our data from the dedicated campaign with the 11-m SALT telescope. These high-quality data allow to study the spectra in much detail (including the spectra decomposition into lines and Fe II pseudo-continuum) in order to determine the possible systematic errors. Later the method will be applied to expected spectroscopic surveys; in addition, current estimates indicate that the project can also be undertaken with a photometric survey of the quality of LSST. The advantage of using quasars lies in their broad range of redshifts, large number of available sources and weak evolution of their metallicity with redshift. |
| 报告人简介： |
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Education:
1974 M.S. in Department of Physics, University of Warsaw
1984 PhD in astrophysics, Copernicus Astronomy center, Poland
Positions and other activities:
1977-1996 assistant and associate professor, Copernicus Astronomical Center
1996 awarded the title of full professor by the President of Poland
1996-2015 professor, Copernicus Astronomical Center
2016-present, Center for Theoretical Physics, Warsaw, Poland
The Scientific Editor of the Astrophysical Journal
Research Interests:
General relativity, particularly the properties of the Kerr metric representing a rotating black hole; Accretion disk and corona properties surrounding the BH and their applications in high-energy objects (X-ray binaries and Active galaxies); The formation mechanism of the broad emission lines in quasars, and the use of quasars as probes of the dark energy. Publish over 200 papers which were quoted above 4700 times, and Hirsch index is 37. |
