Talk detail

Participant	Zhang, Shuang-Nan
Institution	Institute of High Energy Physics - 19B Yu-Quang-Lu - Beijing - Beijing - China

Session	SO2	Accepted	No	Order		Time
Talk	Oral abstract	Title	Quasars' Optical Polarization and Balmer Edge Feature Revealed by Ultra-Violet, and Polarized Visible to Near Infrared Emissions
Co-authors	Renyu Hu
Abstract	Polarized emission from a quasar is produced by wavelength-independent electron scattering surrounding its accretion disc, and thus avoid the contamination from its host galaxy and reveal the intrinsic emission spectrum of the accretion disc. Ultra-violet (UV) emission from a quasar is normally free from the contamination from its host galaxy. Polarization fraction of the quasar's disc emission can therefore be determined by comparing the total UV emission to the polarized visible to near infrared (NIR) emission; and the resulting continuum spectrum from UV to infrared can reveal the theoretically expected Balmer edge absorption feature. We fit the polarized spectra in visible and NIR bands together with the total UV spectra of two type-1 quasars (3C 95, 4C 09.72), to an extended geometrically thin and optically thick accretion disc model. In addition to the standard model, we include the Balmer edge absorption due to co-rotational neutral gas on a narrow annulus of the accretion disc. We find that the extended thin accretion disc model provides adequate description on the continuum spectra of the two quasars from UV to NIR wavelengths. A Monte-Carlo-Markov-Chain fitting to the continuum spectra is able to well constrain the polarization, which allows the Balmer edge feature to be completely revealed in both the UV and polarized visible continua. The Balmer edge feature is prominent in both quasars' spectra, and is significantly broadened due to the orbital motion of gas in the accretion disc. The broadening of the Balmer edge feature is therefore related to the quasar's inclination. This work proves the concept of determining quasar's inclination from the Balmer edge feature in their continuum spectra.

Session	SO5	Accepted	Yes	Order	3	Time	15.10 - 15.45
Talk	Oral abstract	Title	Current status and future plan of China's space astronomy program
Co-authors
Abstract	I will review the current status and future plan of China's space astronomy program, including both satellite missions and asrtonomy experiments onboard China's spacelab and space station.