4 papers
Principal Component Analysis of AGN Spectra
Zhaohui Shang, Beverley J. Wills
We discuss spectral principal component analysis (SPCA) and show examples of its application in analyzing AGN spectra in both small and large samples. It can be used to identify pe…
Indicators of Black Hole Mass and Eddington Accretion Ratio from QSO X-ray and UV Spectra
Beverley J. Wills, Zhaohui Shang
The evolution of luminous QSOs is linked to the evolution of massive galaxies. We know this because the relic black-holes found locally have masses dependent on the properties of t…
The PG X-ray QSO sample: Links between the UV-X-ray Continuum and Emission Lines
Beverley J. Wills, M. S. Brotherton, A. Laor +4
The UV to soft X-rays of luminous AGNs dominate their bolometric luminosity, driven by an accretion-powered dynamo at the center. These photons ionize the surrounding gas, thereby…
Deep Intermediate-Band Surface Photometry of NGC 5907
BATC Collaboration, Z. Y. Zheng, Z. H. Shang +3
We obtained very deep exposures of NGC 5907 with a Schmidt telescope, large-format CCD, and intermediate-band filters centered at 6660A and 8020A. These two filters, part of a 15-f…